Vertebral Columns Winter 2024

INSIDE

Cervical Disc Replacement: Biomechanics, Constraint, and Stability

Vertebral

COLUMNS International Society for the Advancement of Spine Surgery

Photobiomodulation Therapy: Lasers for Low Back Pain?

The Future Role of AI Chatbots in Spine Surgery Preserving Privacy in Big Data Spine Surgery Research: Exploring Federated Learning Solutions Pain Interventionalists and Spine Surgery— Where Is the Line Drawn?

Healthcare Reform and Access to Spine Care in the United States

PLUS

How to Handle Peer-toPeer Calls Aetna’s Policy Threatens Patient Choice and Clinical Excellence

Non-FDA Approved Applications of Cervical Disc Replacement

WINTER 2024

Beyond the Surface: Exploring Cervical Muscle Health in Spine Surgery

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EDITORIAL Non-FDA Approved Applications of Cervical Disc Replacement

CERVICAL SPINE Beyond the Surface: Exploring Cervical Muscle Health in Spine Surgery

Editor in Chief

CERVICAL SPINE

Editorial Board

Cervical Disc Replacement: Biomechanics, Constraint, and Stability

PAIN MANAGEMENT Photobiomodulation Therapy: Lasers for Low Back Pain?

Kern Singh, MD

Peter Derman, MD, MBA Brandon Hirsch, MD Sravisht Iyer, MD Yu-Po Lee, MD

ARTIFICIAL INTELLIGENCE

Sheeraz Qureshi, MD, MBA

The Future Role of AI Chatbots in Spine Surgery

Managing Editor

BIG DATA

Audrey Lusher

Preserving Privacy in Big Data Spine Surgery Research: Exploring Federated Learning Solutions

Designer CavedwellerStudio.com

TRAINING Pain Interventionalists and Spine Surgery—Where Is the Line Drawn?

POLICY Healthcare Reform and Access to Spine Care in the United States

CLINICAL PRACTICE How to Handle Peer-to-Peer Calls

ISASS COMMUNICATION Aetna’s Policy Threatens Patient Choice and Clinical Excellence

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Vertebral Columns is published quarterly by the International Society for the Advancement of Spine Surgery. ©2024 ISASS. All rights reserved.

Opinions of authors and editors do not necessarily reflect positions taken by the Society.

This publication is available digitally at www.isass.org/news/vertebralcolumns-Winter-2024

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EDITORIAL

From the Department of Orthopaedic Surgery at Rush University Medical Center in Chicago, Illinois.

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Non-FDA Approved Applications of Cervical Disc Replacement The first attempt to perform a cervical disc replacement (CDR) was performed in 1966 utilizing a basic ball-bearing device called a Fernstrom cage.1 In 1991, modern CDR was introduced and represented a substantial advancement in implant technology by incorporating an articulated coupling fixated to the vertebral bodies.2 The early iterations of this device yielded unsatisfactory outcomes and various complications.

However, the continued advancement of research devices has demonstrated improvement most noticeably through more favorable improvements in outcomes. 3-5 In contrast to anterior cervical discectomy and fusion (ADCF), CDR distinguishes itself by preserving range of motion (ROM) at the treated spinal level by avoiding the need for fusion.

Several meta-analyses have found that patients who undergo CDR report lower disability and pain, increased ROM, and improved quality of life scores compared to ACDF in the context of degenerative disc disease (DDD) and spondylosis up to 10 years later. 6 –9 Additionally, radiographic analysis found that at 20-year follow-up, seg-

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mental and total cervical ROM were higher and ASD lower in CDR patients compared to in ACDF patients.10 Currently, CDR is only approved by the Food and Drug Administration (FDA) for indications including cervical DDD, spondylotic deformities, intractable radiculopathy, and myelopathy only up to 2 contiguous levels.11 Treatment at 3 contiguous or 2 noncontiguous levels, conversion of nonunion, or treatment of adjacent segment degeneration (ASD) are not FDA approved. Due to the potential benefit of CDR for expanding these indications, we review the current evidence for these off-label uses of CDR.

Treating MCDD Mu lt i le vel c er v ic a l d i sc d i sea se (MCDD) presents unique challenges to spine surgeons aiming to maintain joint stabilit y and achieve proper cer vical lordosis.12 The most commonly performed treatment is ACDF; however, fusion across multiple levels significantly reduces cervical ROM and increases t he risk of ASD. 12,13 The use of CDR in the treatment of 1 and 2 levels is well studied in the

Ishan Khosla, BS

Andrea M. Roca, MS

Fatima N. Anwar, BA

Alexandra C. Loya, BS

Srinath S. Medakkar, BS

Kern Singh, MD

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EDITORIAL

underwent 3-level ACDF and demonstrated similar complication rates, operative time, and blood loss between groups. The authors noted significant improvements in pain and disability scores for both groups and enhanced mobility in the CDR group.19 The best results are strongly associated with optimal patient selection; patients who tend to achieve better outcomes are those with a preoperative disc height of 3 mm, minimal facet degeneration, and a T-score greater than −1.5, indicating no osteoporosis.20

literature. In combination with the widely acknowledged difficulties associated with ACDF and the substantial body of evidence affirming the safety of CDR, many surgeons lean toward CDR for pathologies at >2 levels.13-15 One study investigating CDR across 3 and 4 levels noted significant improvements in neck and arm pain, physical function, mental health, and disability scores across a 10-year follow-up.16,17 Complication and revision rates have demonstrated that multilevel CDR outcomes are less likely to require revision surgery as compared to multilevel ACDF regardless of surgical setting.13,17,18 Another study that matched 50 patients who received 3-level CDR with patients who

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Treating Nonunion via Conversion to CDR Several studies have reported rates of nonunion around 10%-15% at 1 year after cervical fusion. 21-23 Clinically, these patients often present with recurrent radicular or neck pain. 22 In the case of revision ACDF, fusion rates are estimated to be only 44%45%. 24-26 Patients who are noncompliant or have significant risk factors for nonunion such as smoking or diabetes are encouraged to consider CDR, as these factors have less impact on outcomes after disc replacement.22,27-29 Converting a failed ACDF to CDR has several theoretical advantages such as improvement in motion, decreased risk of nonunion, diminished strain on adjacent levels, and speedier recovery. In a case series by the Maryland Spine Center, investigators reviewed 5 ACDF to CDR revisions with a reported 75% decrease in disability scores and an improvement in range of motion of 5° across 4 levels in 3 patients. The most notable case was the conversion 18 years after initial fusion, double the length of time

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EDITORIAL

compared to the previously documented interval of 9 years. 22 Contraindications to converting to CDR include the poor integrity of the endplates at the level of the fusion and facet joint arthrosis. 30

Treating ASD CDR as a compelling alternative to ACDF, the long-standing gold standard procedure, comes due to postfusion complications such as ASD. 3,31-33 While ASD may be a part of the normal aging process, the degenerative process is accelerated following fusion procedures that alter the natural biomechanics of the spine. The current treatment for ASD is additional fusion above and/or below the affected level. However, CDR diminishes biomechanical stress on adjacent joints, thereby mitigating the risk of ASD while also providing heightened patient satisfaction and quality of life. 3,34 As such, CDR offers theoretical advantages over ACDF in the treatment of ASD. A systematic review evaluated evidence of this off-label indication and found that there were significant postoperative improvements in pain and disability.

CDR helped to maintain or improve ROM postoperatively. There were low complication and revision rates in the studies included.

However, only 1 randomized controlled trial was included, with the remaining studies being case series. 35 In the randomized trial, the authors reported that CDRs performed at levels adjacent to prior fusion can still yield similar absolute patient-reported outcomes and improvements in outcomes compared to patients undergoing primary CDR. Two out of 126 patients in the primary group and

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CDR offers similar, if not superior, outcomes compared to ACDF. However, current FDA-approved indications are limited based on the exclusion criteria of the initial FDA trials. While ACDF has been the gold standard, its higher rate of undesirable outcomes and complications continues to influence surgeons to shift toward CDR.

two out of 26 patients in the adjacent level group required revision surgery. 36 Further high-quality evidence with longer-term clinical and radiographic follow-up is required to confirm these findings.

Conclusions CDR offers similar, if not superior, outcomes compared to ACDF. However, current FDA-approved indications are limited based on the exclusion criteria of the initial FDA trials. While ACDF has been the gold standard, its higher rate of undesirable outcomes and complications continues to influence surgeons to shift toward CDR. There remains a need for continued validation of these results with robust prospective studies needed to further explore the use of CDR in these unique indications. Nevertheless, the preliminar y data are promising and offer spine surgeons a unique and effective treatment modality. l

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References 1. Chapman JR, Riew D. Cervical artificial disc replacement: still experimental? Introduction and perspectives on cervical artificial disc replacement.

Evid Based Spine Care J. 2012;3:5–8.

2. Cummins BH, Robertson JT, Gill SS. Surgical experience with an implanted artificial cervical joint. J Neurosurg. 1998;88:943–948.

3. Leven D, Meaike J, Radcliff K, Qureshi S. Cervical disc replacement surgery: indications, technique, and technical pearls. Curr Rev Musculoskelet Med. 2017;10:160–169.

4. Bohlman HH, Anderson PA. Anterior decompression and arthrodesis of the cervical spine: long-term motor improvement. Part I--improvement in incomplete traumatic quadriparesis. J Bone Joint Surg Am. 1992;74:671–682.

5. Seng C, Tow BPB, Siddiqui MA, et al. Surgically treated cervical myelopathy: a functional outcome comparison study between multilevel anterior cervical decompression fusion with instrumentation and posterior laminoplasty. Spine J. 2013;13:723–731.

6. Coric D, ed. Update on Motion Preservation Technologies, An Issue of Neurosurgery Clinics of North America (e-book).

Elsevier Health Sciences, 2021.

7. Luo J, Huang S, Gong M, et al. Comparison of artificial cervical arthroplasty versus anterior cervical discectomy and fusion for one-level cervical degenerative disc disease: a meta-analysis of randomized controlled trials. Eur J Orthop Surg Traumatol. 2015;25(suppl 1):115–125.

8. Gao Y, Liu M, Li T, Huang F, Tang T, Xiang Z. A meta-analysis comparing the results of cervical disc arthroplasty with anterior cervical discectomy and fusion (ACDF) for the treatment of symptomatic cervical disc disease. J Bone Joint Surg Am. 2013;95:555–561.

9. Alluri RK, Vaishnav AS, Fourman MS, et al. Anterior cervical discectomy and fusion versus cervical disc replacement in patients with significant cervical spondylosis. Clin Spine Surg. 2022;35:E327–E332.

10. Foley DP, Sasso WR, Ye JY, et al. 20year radiographic outcomes following single level cervical disc arthroplasty: results from a prospective randomized controlled trial. Spine. Advance online publication November 29, 2023. https:// doi.org/10.1097/BRS.0000000000004888.

11. Cervical disc replacement. Centers for Medicare & Medicaid Services. https://

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www.cms.gov/medicare-coverage-database/view/lcd.aspx?lcdid=38033&ver=13&.

12. Lu VM, Zhang L, Scherman DB, Rao PJ, Mobbs RJ, Phan K. Treating multi-level cervical disc disease with hybrid surgery compared to anterior cervical discectomy and fusion: a systematic review and meta-analysis. Eur Spine J. 2017;26:546–557.

13. Wu T-K, Wang B-Y, Meng Y, et al. Multilevel cervical disc replacement versus multilevel anterior discectomy and fusion: a meta-analysis. Medicine. 2017;96:e6503.

14. Wang X-F, Meng Y, Liu H, Hong Y, Wang B-Y. Surgical strategy used in multilevel cervical disc replacement and cervical hybrid surgery: four case reports. World J Clin Cases. 2020;8:3890–3902.

15. Roussouly P, Pinheiro-Franco JL, Labelle H. Sagittal Balance of the Spine: From Normal to Pathology: A Key for Treatment Strategy. Thieme; 2019.

16. Gornet MF, Schranck FW, Sorensen KM, Copay AG. Multilevel cervical disc arthroplasty: long-term outcomes at 3 and 4 levels. Int J Spine Surg. 2000;14:S41–S49.

17. Tu T-H, Wang C-Y, Chen Y-C, Wu J-C. Multilevel cervical disc arthroplasty: a review of optimal surgical management and future directions. J Neurosurg Spine. 2023;38:372–381.

18. Ifarraguerri AM, Malyavko A, Stoll WT, Gu A, Thakkar SC, Patel T. No significant differences in postoperative complications between outpatient and inpatient single-level or multiple-level cervical disk replacement for cervical radiculopathy. Spine. 2022;47:1567–1573.

19. Joaquim AF, Riew KD. Multilevel cervical arthroplasty: current evidence. A systematic review. Neurosurg Focus. 2017;42:E4.

20. Chang H-K, Huang W-C, Tu T-H, et al.

Radiological and clinical outcomes of 3-level cervical disc arthroplasty. J Neurosurg Spine. 2109;32:174–181.

21. Rhee JM, Ju KL. Anterior cervical discectomy and fusion. JBJS Essent Surg Tech. 2016;6:e37.

22. Kujala ST, Song H, Curto RA, Edwards CC 2nd. Treatment of cervical non-union with cervical disc replacement: a case series.

Int J Surg Case Rep. 2022;93:106922.

23. van Eck CF, Regan C, Donaldson WF, Kang JD, Lee JY. The revision rate and occurrence of adjacent segment disease after anterior cervical discectomy and fusion: a study of 672 consecutive

patients. Spine. 2014;39:2143–2147.

24. Carreon L, Glassman SD, Campbell MJ. Treatment of anterior cervical pseudoarthrosis: posterior fusion versus anterior revision. Spine J. 2006;6:154–156.

25. Koerner JD, Kepler CK, Albert TJ. Revision surgery for failed cervical spine reconstruction: review article. HSS J. 2015;11:2–8.

26. Lowery GL, Swank ML, McDonough RF. Surgical revision for failed anterior cervical fusions. Articular pillar plating or anterior revision? Spine. 1995;20:2436–2441.

27. Ryu WHA, Richards D, Kerolus MG, et al.

Nonunion rates after anterior cervical discectomy and fusion: comparison of polyetheretherketone vs structural allograft implants. Neurosurgery. 2021;89:94–101.

28. Tu T-H, Kuo C-H, Huang W-C, Fay L-Y, Cheng H, Wu J-C. Effects of smoking on cervical disc arthroplasty. J Neurosurg Spine. 2019;30:168–174.

29. Mai E, Shahi P, Lee R, et al. Risk factors for failure to achieve minimal clinically important difference following cervical disc replacement. Spine J. 2023;23:1808–1816.

30. Lanman TH, Cuéllar JM. Restoration of spinal motion: conversion of anterior cervical fusion with pseudarthrosis to artificial disc replacement. Int J Spine Surg. 2020;14:483–487.

31. Steinberger J, Qureshi S. Cervical disc replacement. Neurosurg Clin N Am. 2020;31:73–79.

32. Sharrak S, Al Khalili Y. Cervical disc herniation [updated 2023 Aug 28].

In: StatPearls [Internet]. StatPearls Publishing; 2023. https://www.ncbi. nlm.nih.gov/books/NBK546618/.

33. Virk SS, Niedermeier S, Yu E, Khan SN. Adjacent segment disease. Orthopedics. 2014;37:547–555.

34. Robertson JT, Papadopoulos SM, Traynelis VC. Assessment of adjacent-segment disease in patients treated with cervical fusion or arthroplasty: a prospective 2-year study. J Neurosurg Spine. 2005;3:417–423.

35. Wu T-K, et al. Cervical disc arthroplasty for the treatment of adjacent segment disease: a systematic review of clinical evidence. Clin Neurol Neurosurg. 2017;162;1–11.

36. Phillips FM, et al. Cervical disc replacement in patients with and without previous adjacent level fusion surgery: a prospective study. Spine. 2009;34:556–565.

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¹From the Hospital for Special Sugery in New York, New York; ²From the University Medical Center Hamburg-Eppendorf, HH, in Germany; ³From the University of Tsukuba, Institute of Medicine, in Japan.

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Beyond the Surface Exploring Cervical Muscle Health in Spine Surgery Navigating Neck Stability The dynamic mechanical stability of the neck is intricately governed by two primary elements: the cervical muscles (CMs), which account for 80% of stability, and the osteoligamentous system.1 Although Panjabi first presented the conceptual basis of this active support system in the early 1990s, literature has just recently begun to emphasize CMs’ pivotal functions in maintaining alignment and to link their dysfunction to various pathologies, including neck pain, segmental spinal instability, and compromised postoperative outcomes.1-4 The decline in the structural integrity of muscles is not solely a consequence of aging; it is also directly associated w it h spinal pat holog y.

Studies focusing on the cervical spine speculate that alterations in the struct ure and f unct ion of t he CMs are intricately associated with sagittal balance disorders, reduced spinal mobility, and the onset of chronic neck pain.2,4 Furthermore, the reduction in muscle mass, as a manifestation of musculoskeletal and overall frailty, is independently linked to adverse events in medical and surgical specialties. 3,5

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Beneath the Surface The musculature in the cervical region remains a less studied component of the cervical spine anatomical compartments. The coordination of CMs ensures dynamic spine stability during neck movements, which is built on a complex equilibrium of more than 20 pairs of CMs, which can be categorized according to their primary function as flexors, extensors, lateral flexors, or rotators.

The cervical region is further divided into a suboccipital and mid-to-lower cervical area with distinct layering of the CM. The latter is further separated into a ventral and dorsal compartment.

The ventral muscle layer is composed of superficial muscles (eg, platysma and sternocleidomastoid muscle) and a deep muscle layer (including the scalenus group, longus group, and infrahyoid group).6 Similarly, the dorsal muscle layer is categorized into a superficial layer originating from the occiput, the ligamentum nuchae and spinous processes of the upper spine (t rapezius, splenius, and elevator scapulae muscles), an intermediate layer k now n as the erector spinae group (comprising semispinalis, iliocostalis, and longissimus muscles),

Annika Heuer, MD1,2

Justin Samuel, BS1

Joshua Zhang, BS1

Tomoyuki Asada, MD1,3

Sheeraz A. Qureshi, MD, MBA1

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and a deep layer that encompasses the transversospinalis muscle group. 6 In the upper cervical region, the dorsal paraspinal muscles (CPMs) support the midline tension band, which is crucial for counterbalancing the weight of the cranium and sustaining a horizontal gaze.7 Acc u rate pla n n i ng of cer v ica l spi ne surgery relies on recognizing the variable landmarks of neck muscles. W hile sexbased dimorphism in cer v ical osseous morpholog y is well established, muscle differences are scarcely examined. Male vertebrae differ significantly from female vertebrae, and male posture shows a reduced upper cervical lordosis compared to female alignment. Furthermore, male CPMs generate stronger torque, attributed to a larger cross-sectional area (cSA). Postural differences, increased head circumference, and varied bony anatomy contribute to distinct mechanical demands and promote differing geometric moment arm variations in CMs.8 A cadaver study by Keidan et al identified sex-based dimorphism in the spinotransversales (splenius capitis and cervicis) and the multifidus muscles and suggested that specific differences in muscle attachment sites may explain sex-related disparities in muscle torque production and movement.

Current literature reinforces the notion that the female neck is not a scaled version of the male neck. 8

Assessment of Muscle Health Recent studies demonstrated that the assessment of cSA and fatty infiltration (FI) as parameters for CM health can serve as pre-

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dictive indicators for postoperative outcome.

While the individual cSA also depends on sex and body shape, it correlates with the gradual decrease in muscle mass (atrophy) that starts from the third decade of life, with up to 50% of mass being lost by the eighth decade of life. 9 The evaluation of CM-cSA primarily involves manual encircling of the fascial boundaries of the CM (longus colli, multifidus, and sternocleidomastoid muscles) in magnetic resonance imaging (MRI) slices.10 More recently, growing emphasis has focused on overall muscle quality and function instead of solely muscle mass. FI in skeletal muscle plays a crucial role in reducing both muscle strength and function. 2 With aging, the extracellular matrix is transformed to contain a higher proportion of fat, which is a distinct structural change in the skeletal muscle, known as myosteatosis. While this process is inherently natural, FI is linked to spinal pathologies such as chronic back pain, spinal deformit y, and immobilit y.

Another mechanism for FI over time is disuse-induced atrophy.11 The assessment of FI commonly ut ilizes t he Goutallier classification system. In this approach, qualitative analysis of MRI is used to assign grades regarding the degree of FI, utilizing a numeric scale ranging from 0 to 4, where 0 signifies lean and 4 indicates a higher fat than muscle proportion.12 Excessive loss of muscle strength and power itself has been recognized as a serious debilitating condition.3,5,13 Such age-related, involuntary loss of skeletal muscle mass and strength can be referred to as sarcopenia.

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Advocacy for assessing paraspinal sarcopenia has shifted toward the qualitative evaluation of FI as the comparability of cSA measurements is largely dependent on exact axial slicing at the same level/landmark.

FI in sarcopenic patients was show n to strongly correlation with patient-reported outcome measures and can be conveniently acquisitioned on preoperative MRIs. 3,14

Recovery Roadblocks: Pre- and Postoperative Considerations While muscle health of the paravertebral lumbar region has been extensively evaluated, few studies have focused on postoperative outcomes and CM health, but a similar effect on outcomes has been described in small scale studies.

Choi et al assessed the correlation between the preoperative cSA of the deep CPM and bone union in individuals who underwent C5/6 single-level anterior cervical decompression and fusion (ACDF) without anterior plate fixation. In their study, the CPM-cSA measurements at C5/6 correlated with a decreased risk of nonunion in both women and men. As ventral muscle groups recover, deep CPMs are the primary stabilizers during the early postoperative phase. Moreover, the study showed that as the CPM-cSA increased, fusion time decreased.10 Another study conducted a retrospective examination of preoperative MRIs, which revealed that multifidus and semispinalis muscles’ cSA, along with unilateral asymmetries, were linked to early-onset adjacent segment disease (ASD) after 2-level ACDF in the lower cervical spine. The authors

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postulated that the correlation between cSA measurements and early-onset ASD implies that the relative composition/quality and size of deep CPM influences cervical spine recovery on a biomechanical level.15 Virk et a l inter preted CPM hea lt h as the maintained ability of neck extension needed to sustain horizontal gaze. Their study findings indicated a protective effect of muscle density in relation to range of motion (extension reserve) while CPM-FI was associated with a decline in neck extension. The research demonstrated a positive correlation of cSA and muscle density with overall cer vical alignment. In addition, CPM-FI was tied to a postoperative loss of cervical alignment in their study cohort.7 Suppor t i ng t he l i n k bet ween FI a nd alignment, Kim et al tied extensor FI at a C2/3 level of nonsurgically treated neck pain patients to a loss of cervical lordosis.

Moreover, extensor FI at a C6/7 level was associated w it h higher VAS scores and poorer neck function.16 Additionally, in a group of patients undergoing imaging due to conservatively treated cervical spondylosis, a greater CPM-FI was linked to a higher probability of sagittal imbalance compared with healthy subjects. 2 He et al further showed a positive correlation between severe CPM-FI and postoperative sagittal balance disorder as well as worse segmental alignment after continuous 2-level hybrid surgery in patients treated due to refractory degenerative disc disease with radiculopathy and/or myelopathy.4 Weakness associated with CPM-FI decreases spinal stability, which has been

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associated with degenerative osteoarthritis of the spine, directly tying muscle quality changes to mechanical neck pain. In terms of clinical results, study data could show an existing connection between higher CPM degeneration and worsened patient-reported outcomes after ACDF. Hence, preoperative assessment of FI is recommended to improve patient-centered care. 2,4 In patients undergoing double-floor cervical laminoplasty, the C2-C7 sagittal vertical axis was shown to be higher and postoperative outcomes found to be worse when sarcopenia was diagnosed. The authors indicated the need to screen for sarcopenia because it can negatively impact cervical

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alignment and overall surgical outcome. 5 Moreover, the severity of age-related muscle loss/sarcopenia was associated with heightened neck disability and diminished physical function following C2-T1 posterior cervical decompression and fusion. 3 Paraspinal muscular degeneration/atrophy in the lumbar spine was shown to be multifactorial caused by mechanical injury, ischemia, denervation, retraction time, a midline approach, and disuse associated with bracing.11,17 Depending on the surgical approach, the intervention, and individual preferences, patients sometimes receive soft or stiff braces during postoperative care, restricting movement to facilitate healing

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and bony fusion. Research demonstrated that postoperative bracing for 4-6 weeks after a CPM-sparing ventral approach (ACDF) did not result in persisting disuse atrophy w it h no sig n i f ica nt CPM-cSA cha nges postoperatively.10 Another study indicates that HALO west fixation for 3 months did lead to a 15% and 22% atrophic reduction for the sternocleidomastoid muscle and the nuchal muscle group, respectively, but that atrophy was fully reversible upon removal.

Recovery potential might be dependent on the individual preoperative muscle health outset.10

Tomorrow’s Tools Minimally invasive surgical (MIS) techniques are an expanding innovation to spine surger y, characterized by smaller incisions, minimized muscle disruption, and accelerated postoperative recover y.

MIS for pathologies of the cervical spine were linked to notable enhancements in patient-reported outcome measures, range of motion, alignment, and preserved tissue.18 In animal studies, lumbar paraspinal atrophy due to late denervation could be reduced by releasing retractors regularly and shorter retraction times. The CPMs are innervated by the medial branch of the posterior rami, which passes slightly lateral to the pars interarticularis and facet joints.

Sangala et al described a ner ve sparing cervical technique, which limited lateral exposure to the medial two-thirds of the lateral mass and decreased secondary atrophy.17 In another study, laminectomy with fusion was shown to be an independent risk

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factor for secondary atrophy compared to a laminoplasty approach alone in patients w ith cer vical spondylotic myelopathy.11 Implementation of MIS techniques might further reduce postoperative atrophy by minimizing tissue damage and pain/function-related immobilization.

Personalized preoperative and postoperative rehabilitation programs are emerging advancements to patient care. Although the irreversible degenerative changes in myofascial tissue progress over time, the impact of aging can be slowed, and muscle function can be preserved. It is established that maintaining even a minimal level of physical activity can slow the accumulation of connective tissue in aging muscles and delay qualitative decline.13 Strengthening and conditioning exercises tailored to individual patient needs can enhance muscle health, improve recovery, and potentially minimize postoperative complications.

Pre-rehabilitation prior to spine surgery has been shown to slightly improve pain, disability, strength, endurance, ambulation, and mobility.19 In addition, early structured rehabilitation after surgery demonstrated improved outcomes and shortened hospital stay without increasing complication rates, pain scores, or dissatisfaction. 20 Assessment of muscle health, especially cSA, is a time-consuming process of muscle segmentation and is mostly done manually by medical staff.14 Artificial intelligence (AI) holds promise in revolutionizing the screening and interpretation of imaging studies, including MRIs and computed tomography images. Recently, AI demon-

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strated success in quantifying and assessing muscle parameters using MR I and computed tomography images, including muscle density, cSAs, and FI.15 AI-powered algorithms can assist surgeons in efficient muscle health analysis and risk detection and facilitate more efficient tailoring of individualized treatment plans. 21

A comprehensive assessment of patients’ muscle function is crucial in prevention and treatment of patients w ith cer vical pathologies. Personalized pre-rehabilitation might further enhance both muscle streng t h and qualit y, which ultimately improves muscle health and delays muscle degeneration. 2 l

References 1. Panjabi MM, Cholewicki J, Nibu K, Grauer J, Babat LB, Dvorak J. Critical load of the human cervical spine: an in vitro experimental study.

Clin Biomech. 1998;13(1):11-17.

2. Li Z, Liang Q, Li H, et al. Fatty infiltration of the cervical multifidus musculature and its clinical correlation to cervical spondylosis. BMC Musculoskelet Disord. Jul 27 2023;24(1):613.

3. Pinter ZW, Salmons HIt, Townsley S, et al. Multifidus sarcopenia is associated with worse patient-reported outcomes following posterior cervical decompression and fusion. Spine (Phila Pa 1976). Oct 15 2022;47(20):1426-1434.

4. He J, Wu T, Ding C, Wang B, Hong Y, Liu H. The fatty infiltration into cervical paraspinal muscle as a predictor of postoperative outcomes: a controlled study based on hybrid surgery. Front Endocrinol. 2023;14.

5. Koshimizu H, Sakai Y, Harada A, Ito S, Ito K, Hida T. The impact of sarcopenia on cervical spine sagittal alignment after cervical laminoplasty. Clin Spine Surg. 2018;31(7):E342-e346.

6. Pawl RP. Surgical exposure of the spine: an extensile approach.

Surg Neurol. 1997;1(47):96.

7. Virk S, Lafage R, Elysee J, et al. Cervical paraspinal muscle fatty infiltration is directly related to extension reserve in patients with cervical spine pathology.

Clin Spine Surg. 2023;36(1):e22-e28.

8. Keidan L, Barash A, Lenzner Z, Pick CG, Been E. Sexual dimorphism of the posterior cervical spine muscle attachments. J Anat. 2021;239(3):589-601.

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9. Bafei SEC, Yang S, Chen C, et al. Sex and age differences in the association between high sensitivity C-reactive protein and all-cause mortality: a 12-year prospective cohort study.

Mech Ageing Dev. 2023;211:111804.

15. Wong AYL, Harada G, Lee R, et al. Preoperative paraspinal neck muscle characteristics predict early onset adjacent segment degeneration in anterior cervical fusion patients: a machine-learning modeling analysis. J Orthop Res. 2021;39(8):1732-1744.

10. Choi MK, Kim SB, Park CK, Lee SH, Jo DJ. Relation of deep paraspinal muscles’ cross-sectional area of the cervical spine and bone union in anterior cervical decompression and fusion: a retrospective study. World Neurosurg. 2016;96:91-100.

16. Kim CY, Lee SM, Lim SA, Choi YS. Impact of fat infiltration in cervical extensor muscles on cervical lordosis and neck pain: a cross-sectional study.

Clin Orthop Surg. 2018;10(2):197-203.

11. Ashana AO, Ajiboye RM, Sheppard WL, Sharma A, Kay AB, Holly LT. Cervical paraspinal muscle atrophy rates following laminoplasty and laminectomy with fusion for cervical spondylotic myelopathy.

World Neurosurg. 2017;107:445-450.

12. Slabaugh MA, Friel NA, Karas V, Romeo AA, Verma NN, Cole BJ. Interobserver and intraobserver reliability of the Goutallier classification using magnetic resonance imaging: proposal of a simplified classification system to increase reliability. Am J Sports Med. 2012;40(8):1728-1734.

13. Kocur P, Tomczak M, Wiernicka M, Goliwąs M, Lewandowski J, Łochyński D. Relationship between age, BMI, head posture and superficial neck muscle stiffness and elasticity in adult women. Sci Rep. 2019;9(1):8515.

14. Elliott JM, Cornwall J, Kennedy E, Abbott R, Crawford RJ. Towards defining muscular regions of interest from axial magnetic resonance imaging with anatomical cross-reference: part II - cervical spine musculature. BMC Musculoskelet Disord. 2018;19(1):171.

17. Sangala JR, Nichols T, Freeman TB. Technique to minimize paraspinal muscle atrophy after posterior cervical fusion.

Clin Neurol Neurosurg. 2011;113(1):48-51.

19. Szewczyk BS, Riccio AR, Entezami P, German JW. The effect of minimally invasive dorsal cervical decompression for myelopathy on spinal alignment and range of motion. Clin Neurol Neurosurg. 2020;196:105967.

20. Marchand AA, Houle M, O’Shaughnessy J, Châtillon C, Cantin V, Descarreaux M. Effectiveness of an exercise-based prehabilitation program for patients awaiting surgery for lumbar spinal stenosis: a randomized clinical trial. Sci Rep. 2021;11(1):11080.

21. Nielsen PR, Jørgensen LD, Dahl B, Pedersen T, Tønnesen H. Prehabilitation and early rehabilitation after spinal surgery: randomized clinical trial.

Clin Rehabil. 2010;24(2):137-148.

22. Weber KA, 2nd, Abbott R, Bojilov V, et al. Multi-muscle deep learning segmentation to automate the quantification of muscle fat infiltration in cervical spine conditions. Sci Rep. 2021;11(1):16567.

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CERVICAL SPINE

From Midwest Orthopaedic at Rush, Rush University Medical Center, in Chicago, Illinois.

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Cervical Disc Replacement Biomechanics, Constraint, and Stability

The convent ional met hodolog y for addressing degenerative cervical pathology involves a fusion procedure, often utilizing an anterior approach, discectomy, and static implants. Several notable drawbacks from this approach include the loss of cervical motion and inducement of adjacent segment pathology.1 In response to these challenges, cervical disc arthroplasty has emerged as an alternative to fusion, with the primary goal of preserving physiologic motion while still addressing spondylotic pathology.

The first cervical disc arthroplasty was conceived in the 1960’s with the insertion of a metallic sphere within the annulus fibrosis, sustaining motion following the removal of a symptomatic disc. 2 Despite initial successes, the approach resulted in significant complication rates, particularly with subsidence and loss of motion. 3 Modern implant designs have improved clinical outcomes compared to their early counterparts. These contemporary designs vary in terms of degree of constraint, number of components, mode of articulation, materials used, and mechanisms of osteointegration.4 While technique is of utmost importance in its success, significant challenges persist in disc replacement, necessitating ongoing efforts to optimize implants, reduce wear, prevent migration, and prevent adjacent segment disease.

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Design Mechanics Cervical disc arthroplasty implants are classified as single unit or multicomponent designs.

Initial designs of nonarticulating and monoblock designs William Conaway, MD included t he R hine (Str yker) and Bryan (Medtronic) implants.

These implants allowed for compressibility in 3 axes and thus allowed 6 deg rees of mot ion freedom (DOF), mimicking native disc mechanical properties. However, this also led to Arash J. Sayari, MD increased constraint and often failures. More recently, M6 (Orthofix) has incorporated an artificial fiber annulus around the polycarbonate urethane polymeric center, which increases resistance to bending in a manner similar to the native annulus. These monoblock designs inherently direct shear stresses to the implant-bone interface, potentially increasing the risk for migration and failure. 5 Additionally, as the center of rotation is fixed in these designs, placement of the implant at the native center of rotation is crucial.

Multicomponent designs directly address these design limitations inherent to monoblock designs by translating shear force to motion at one or more articulating surfaces.

This reduces strain at the implant-bone in-

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terface. Additionally, the center of rotation in some of these designs can mobilize with translation at the articulating surfaces, allowing for restoration of physiologic motion, somewhat regardless of implant position.6 With articulating designs, function is defined by form and the specifics of that form have significant implications for implant motion.

Three-component devices, such as the Simplify (Nuvasive) and Mobi-C (Zimmer) artificial cervical discs, typically involve 2 articulating bearings, providing a total of 5 DOF. In comparison to the monoblock designs, these articulating designs lack compressibility along the cranial-caudal

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axis. The Simplify Artificial Cervical Disc incorporates a biconvex mobile core sandwiched between two PEEK ceramic endplates. This core allows for angulating in flexion-extension and lateral bending while also being able to translate anterior-posterior and right-left, thus moving the center of rotation while also self-centering the implant.7 In a similar fashion, the Mobi-C device forms a ball-and-socket bearing with the mobile core in its more cranial articulation to provide flexion-extension, lateral bending, and axial rotation, while the caudal articulation provides only translation.8 This configuration where the convex surface or ‘ball’ is allowed to translate is referred to as ‘ball in trough’ and is defined by the mobile center of rotation.

In 2-component devices such as the Discover Artificial Cervical Disc (Depuy) and ProDisc-C (Centinel), the ball and socket joint is not mobile and therefore only allows for rotation, lateral bending, and flexion-extension in the absence of translation. This design mitigates less of the transferred shear forces on the bone-implant interface and must be placed as close to the exact center of rotation of the native spinal unit given that the center of rotation cannot move.7

Constraint Disc arthroplast y implants can also be broadly categorized as unconstrained or constrained with unconstrained implants allowing for beyond physiologic range of motion and constrained implants limiting range of motion by design.9 More constrained designs may offer better initial stability but

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will transmit greater shear forces to adjacent levels. The Mobi-C, for example, is less constrained, while the ProDisc-C is more constrained. Less constrained designs will offer less stability but transmit less shear force, as previously described.

Stability Implant stability in the short term is determined by fixation. Some designs utilize keels or rails for a press-fit mechanism that provides immediate vertebral fixation. The drawback of these enhanced stability devices is the disruption of the endplate cortical surface and release of mesenchymal substrates from the cancellous bone into the wound bed. This has been shown to increase the rate of heterotopic ossification and iatrogenic fusion.10 Implants with spikes or teeth offer less initial stability but with the added benefit of less endplate disruption. Implant stability in the long term is dependent on osseous integration to the adjacent verte-

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bral bodies. Material characteristics, initial fixation, and avoidance of complications such as infection or aseptic loosening are essential in this process.11

Materials The materials used in cervical disc arthroplasty implants play a pivotal role in determining their mechanical properties and biocompatibility. Common materials include stainless steel, polyethylene, polyurethanes, titanium, and cobalt-chromium alloys.11 Titanium and cobalt-chromium alloys are particularly favored for their robust mechanical properties and resistance to corrosion.

Titanium implants may exhibit wear-related issues with their oxide surface layer, potentially leading to particulate debris generation and inf lammatory reactions. In contrast, cobalt-chromium alloys are renowned for their durability and resistance to wear. This metal is utilized in the Secure-C, Mobi-C, and ProDisc-C. l

References ment of 2-level symptomatic degenerative disc disease: a prospective, randomized, controlled multicenter clinical trial. J Neurosurg Spine. 2013;19(5):532-545.

1. Epstein NE. A review of complication rates for anterior cervical diskectomy and fusion (ACDF). Surg Neurol Int. 2019;10:100.

5. Staudt MD, Das K, Duggal N. Does design matter? Cervical disc replacements under review. Neurosurg Rev. 2018;41(2):399-407.

2. Fernström U. Arthroplasty with intercorporal endoprothesis in herniated disc and in painful disc. Acta Chir Scand Suppl. 1966;357:154-159.

6. Maayan O, Shafi I, Qureshi S. Update on design and biomechanics of cervical disc arthroplasty. Semin Spine Surg. 2023;35(1):101009.

9. Patwardhan AG, Havey RM. Biomechanics of cervical disc arthroplasty devices.

Neurosurg Clin N Am. 2021;32(4):493-504.

3. Bono CM, Garfin SR. History and evolution of disc replacement. Spine J. 2004;4(6 suppl):S145-S150.

7. Patwardhan AG, Havey RM. Biomechanics of cervical disc arthroplasty—a review of concepts and current technology. Int J Spine Surg. 2020;14(s2):S14-S28.

10. Mehren C, Suchomel P, Grochulla F, et al.

Heterotopic ossification in total cervical artificial disc replacement. Spine (Phila Pa 1976). 2006;31(24):2802-2806.

8. Davis RJ, Kim KD, Hisey MS, et al. Cervical total disc replacement with the Mobi-C cervical artificial disc compared with anterior discectomy and fusion for treat-

11. Saini M. Implant biomaterials: a comprehensive review. World J Clin Cases. 2015;3(1):52.

4. Leven D, Meaike J, Radcliff K, Qureshi S. Cervical disc replacement surgery: indications, technique, and technical pearls. Curr Rev Musculoskelet Med. 2017;10(2):160-169.

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PAIN MANAGEMENT

From the Texas Back Institute in Plano, Texas.

Photobiomodulation Therapy Lasers for Low Back Pain?

Photobiomodulation t herapy (PBMT) is a light-based intervention that has gained attention as a noninvasive treatment for musculoskeletal disorders.

It involves the application of Peter B. Derman, MD, light to the skin, typically via MBA lasers. Low-level laser therapy, also known as cold laser, does not produce heat. Hight-intensity laser therapy involves the use of a more powerful laser (>500 mW) and can produce thermal effects. Multiple mechanisms of action have been proposed, but light may interact with photoreceptors

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within the mitochondria of various tissues to stimulate positive effects such as increases in cellular metabolism.1 Proponents claim a wide variety of benefits including positive anti-inflammatory, analgesic, metabolic, immunologic, neurologic, and vascular effects.

Basic science and animal investigations have suggested that PBMT may modulate the cellular response to inflammatory cytokines, reduce neuropathic pain, counteract muscle atrophy, and promote tendon healing. 2–5 Furthermore, clinical studies have observed positive effects of PBMT for the treatment of a variety of musculoskeletal

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PAIN MANAGEMENT

disorders, including knee osteoarthritis, shoulder tendinopathy, and temporomandibular disorders.6–8 The American Academy of Orthopaedic Surgeons now includes laser therapy in its clinical practice guidelines for the nonoperative management of knee osteoarthritis (limited strength recommendation),9 and the Centers for Disease Control and Prevention lists laser therapy as an alternative to opioids for the treatment of subacute and chronic pain.10 However, questions remain regarding the utility of PBMT for low back pain. While the American College of Physicians includes laser therapy in their guidelines for the treatment of low back pain (LBP), they note that the existing evidence is of low quality and the treatment effect is not large.11 This may be because the penetration depth required to reach the spine is greater than that of peripheral joints and superficial tissues.

Penetration depths of up to 1-2 cm reported in the literature would seem inadequate to impact the deep spinal structures.12 Promotional materials for laser therapy13 quote a penetration of up to 4-5 cm; but no evidence is provided to support these claims, and this distance would still be insufficient to reach the spine in many instances.

Several systematic reviews have been published on the impact of light-based therapy on patients with low back pain. A 2008 Cochrane review found insufficient data to support the clinical use of PBMT for the treatment of acute, subacute, or chronic LBP.14 Additional systematic reviews were published in 2015 and 2016 looking specifically at the effectiveness of PBMT for chronic LBP; these

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While questionably effective, this therapeutic modality does seem to be safe, so the main risks of trying it are likely the potential for wasted time and money. Interested patients may therefore consider it as a potential adjunct to more established conservative care modalities. included 7 and 15 randomized controlled trials (RCTs), respectively.15,16 Authors of both studies concluded that there was a positive treatment effect.

Tomazoni et al published a systematic review of PBMT for LBP in 2020.1 They identified 12 RCTs containing a total of 1,046 patients and determined that PBMT did not provide a clinically important effect on pain and disability in patients with LBP of any duration. Authors concluded that there was not sufficient evidence for PBMT to support its use in patients with LBP. Meanwhile, a 2021 systematic review and meta-analysis analyzing 19 RCTs concluded that laser therapy reduced low back pain in the short term, but this effect did not persist beyond 3 months. Improvements in range of motion and Oswestry Disability Index scores were also observed.17 Even more recently, a 2023 systematic review and meta-analysis by Abdildin et al reported statistically significant improvements in chronic low back pain as well as in disability scores for patients treated with laser therapy.18

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It is difficult to draw definitive conclusions on the effectiveness of PBMT from such conflicting reports. The lack of standardized protocols as well as a variety of laser types certainly contribute to the heterogeneity observed in the data. Non-specific LBP itself is a catch-all diagnosis that encompasses multiple etiologies for pain, some of which may be amenable to light-based therapies while others might not. Because PBMT does not tend to be covered by health insurance in the United States, patients who desire

it generally must pay out of pocket. While questionably effective, this therapeutic modality does seem to be safe, so the main risks of trying it are likely the potential for wasted time and money. Interested patients may therefore consider it as a potential adjunct to more established conservative care modalities. However, healthcare specialists would be prudent to await more convincing evidence before officially endorsing the use of lasers for the nonsurgical treatment of low back pain. l

References 1. Tomazoni SS, Almeida MO, Bjordal JM, et al. Photobiomodulation therapy does not decrease pain and disability in people with non-specific low back pain: a systematic review. J Physiother. 2020;66(3):155-165.

2. Genah S, Cialdai F, Ciccone V, Sereni E, Morbidelli L, Monici M. Effect of NIR laser therapy by MLS-MiS source on fibroblast activation by inflammatory cytokines in relation to wound healing. Biomedicines. 2021;9(3):307.

3. Micheli L, Cialdai F, Pacini A, et al.

Effect of NIR laser therapy by MLSMiS source against neuropathic pain in rats: in vivo and ex vivo analysis. Sci Rep. 2019;9(1):9297.

4. Monici M, Cialdai F, Romano G, et al.

Effect of IR laser on myoblasts: prospects of application for counteracting microgravity-induced muscle atrophy. Microgravity Sci Technol. 2013;25(1):35-42.

5. Iacopetti I, Perazzi A, Maniero V, et al. Effect of MLS® laser therapy with different dose regimes for the treatment of experimentally induced tendinopathy in sheep: pilot study. Photomed Laser Surg. 2015;33(3):154-163.

6. Stausholm MB, Naterstad IF, Joensen J, et al. Efficacy of low-level laser therapy on pain and disability in knee osteoarthritis: systematic review and meta-analysis of randomised placebo-controlled

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trials. BMJ Open. 2019;9(10):e031142.

7. Haslerud S, Magnussen LH, Joensen J, Lopes-Martins RAB, Bjordal JM. The efficacy of low-level laser therapy for shoulder tendinopathy: a systematic review and meta-analysis of randomized controlled trials. Physiother Res Int J Res Clin Phys Ther. 2015;20(2):108-125.

8. Shukla D, Muthusekhar MR. Efficacy of low-level laser therapy in temporomandibular disorders: a systematic review.

Natl J Maxillofac Surg. 2016;7(1):6266. doi:10.4103/0975-5950.196127 9. American Academy of Orthopaedic Surgeons. Management of Osteoarthritis of the Knee (Non-Arthroplasty): Evidence-Based Clinical Practice Guideline. Published online August 31, 2021. https://www.aaos.org/oak3cpg 10. Dowell D. CDC clinical practice guideline for prescribing opioids for pain — United States, 2022. MMWR Recomm Rep. 2022;71. doi:10.15585/mmwr.rr7103a1 11. Qaseem A, Wilt TJ, McLean RM, et al. Noninvasive treatments for acute, subacute, and chronic low back pain: a clinical practice guideline from the American College of Physicians. Ann Intern Med. 2017;166(7):514-530.

12. Vignali L, Cialdai F, Monici M. Effects of MLS laser on myoblast cell line

C2C12. Energy Health. 7:12-18.

13. MLS Laser Therapy. Accessed November 24, 2023. https://www.thefootanklecenter.com/mls-laser-therapy.html 14. Yousefi-Nooraie R, Schonstein E, Heidari K, et al. Low level laser therapy for nonspecific low-back pain. Cochrane Database Syst Rev. 2008;2008(2):CD005107.

15. Huang Z, Ma J, Chen J, Shen B, Pei F, Kraus VB. The effectiveness of low-level laser therapy for nonspecific chronic low back pain: a systematic review and meta-analysis. Arthritis Res Ther. 2015;17:360.

16. Glazov G, Yelland M, Emery J. Low-level laser therapy for chronic non-specific low back pain: a meta-analysis of randomised controlled trials. Acupunct Med J Br Med Acupunct Soc. 2016;34(5):328-341.

17. Chen YJ, Liao CD, Hong JP, Hsu WC, Wu CW, Chen HC. Effects of laser therapy on chronic low back pain: A systematic review and meta-analysis of randomized controlled trials.

Clin Rehabil. 2022;36(3):289-302.

18. Abdildin Y, Tapinova K, Jyeniskhan N, Viderman D. High-intensity laser therapy in low back pain management: a systematic review with meta-analysis.

Lasers Med Sci. 2023;38(1):166.

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From the Hospital for Special Surgery in New York, New York.

ARTIFICIAL INTELLIGENCE

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The Future Role of AI Chatbots in Spine Surgery Hea lt hca re i n novat ion is ex per iencing a remarkable surge due to recent breakt hroughs in artif icial intelligence (AI) technology, notably in the form of readily available large language models (LLMs). LLMs such as ChatGPT (Chat Generative PreTrained Transformer) seek to mimic human language processing abilities.1 A variety of recent publications have showcased ChatGPT’s potential in tasks rang ing from responding to patients’ clinical inquiries to passing medical examinations. 2–5 While the practically unlimited future applications of ChatGPT are promising, it is uncertain when surgeons can expect to see widespread implementation of its capabilities. The utilization of chatbots to facilitate patient communication has already begun, and it likely represents one of the uses that will see the earliest widespread adoption in the field of spine surgery.

Given the expected increased utilization of AI chatbots as a conduit for patient communication, we explore its possibilities in the present article.

Patient Communication The integration of AI in spine surgery can significantly alter patient com-

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munication, making it more efficient and diverse. The initial contact of scheduling an appointment can be supplemented with a chatbot, enabling the user to initiate a dialog to which the chatbot can provide a tailored response. Furthermore, a chatbot can prioritize appointments based on a patient’s responses and even guide patients to the most appropriate specialty. 5 For example, Subramanian et al 2 reported several responses ChatGPT provided when asked spine surgery– related questions. In response to the question “I have back pain radiating down my leg. What should I do and what type of doctor should I see?”, ChatGPT concluded its response by writing, “In summary, it’s important to seek medical attention if you have back pain radiating down your leg, and your primary care physician or a specialist such as a spine specialist, orthopedist, or neurologist can help determine the best course of treatment for you.”2 This ability has the potential to reduce the number of unnecessar y referrals, which is critical given that orthopedic surgeons have one of the busiest clinic schedules with significant wait times.6 As intelligent conversational agents,

Kasra Araghi, BS

Amy Z. Lu, BS

Eric Kim, BS

Tomoyuki Asada, MD

Sravisht Iyer, MD

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chatbots can educate patients about their concerns, preparing them to engage in a deeper and more educated discussion with their providers.7 In post-visit situations, these chatbots provide an accessible platform for patients to seek information and clarification. For example, a chatbot can answer questions about side effects or interactions a prescribed medication may have. Rather than referencing websites with general information like WebMD, a chatbot could theoretically reference its continuously updated repository of knowledge or available clinical documentation to provide individualized information in an understandable style for the patient. Given that orthopedic surgeons tend to receive more questions than other surgical specialties, 6 an innovation that minimizes the burden of electronic health

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record (HER) messages would be a welcome shift. Implementation of a chatbot does not imply they have to fully replace this responsibility; physicians can also utilize ChatGPT to augment their normal workflow of responding to patients. However, with limited time in busy clinics, it is difficult to provide patients with a response that is both engaging and empathetic. Although privacy concerns must be considered, ChatGPT can solve this problem by restyling a provider’s response to add more empathy and engagement, and studies have shown that patients prefer ChatGPT-authored responses. 8 Despite the efficiency of AI in handling routine tasks and explaining clinical documentation, its role in the informed consent process is limited. 9,10 In spine surgery, where patients require a comprehensive understanding of their procedures, AI tools

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may fall short in delivering the nuanced and personalized information necessary for informed consent. Human intervention remains crucial to fill this gap, ensuring patients are well-informed and engaged in their healthcare decisions. ChatGPT and other technologies can enhance a surgeon’s practice, but they cannot replace human interaction.

Medical Documentation The burden of documentation, from writing office visit notes and patient letters to interpreting test results, is a laborious responsibilit y. A 2016 survey found that at least 70% of physicians attributed their administrative burden to their EHR use.11 Reports have show n the majorit y of an academ ic or t hoped ic su rgeon’s day is spent completing EHR tasks compared to face-to-face patient time. 6 Chatbots offer the potential to reduce this signif icant administrative time commitment, which is vital as the burden increases the risk of physician burnout.12 Companies like Microsoft, Amazon, and Google have all introduced their own AI tools to improve the efficiency of physician medical documentation. By using natural language processing, the subfield of AI that focuses on the recognition of human language, these tools are particularly useful for processing speech into medical records.13 For example, through a partnership with Nuance, Microsoft launched Dragon Ambient eXperience Express (DAX), an automated clinical documentation app that is “the first application to combine proven conversa-

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tional and ambient AI with the advanced reasoning and natural language capabilities of OpenAI’s GPT-4.”14 They found the technology saved physicians 7 minutes on average per encounter; in turn, physicians reported a 70% decrease in feelings of burnout and fatigue.15 Amazon developed a tool called HealthScribe, which uses generative AI to create patient transcripts and visit summaries that can be uploaded to EHR.16 Google partnered with Suki to develop a voice-enabled assistant that uses AI to help physicians with administrative tasks and found it resulted in a 76% decrease in physician’s average time per note.17 Even in the early stages of clinical use, these tools have shown improved efficiency in the medical documentation process. ChatGPT can also lighten the burden of documentation by generating clinic letters. In pilot studies, ChatGPT has shown promising results in this task, producing letters with high overall correctness and humanness.18

Present and Future of Chatbots One of the primary concerns with the use of AI chatbots is the quality of the information they provide. AI chatbots generate responses based on the data with which they were trained, which gives it the potential to provide biased, incomplete, and inaccurate responses.19 Previous investigations, for example, have described ChatGPT’s propensity toward making conclusive statements in response to spine surgery questions that lack a consensus answer in the literature. 2 The conclusive statements also demonstrate its capacity for bias, as ChatGPT described

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minimally invasive spine surgery as a superior approach compared to the traditional open approach. While there are certain advantages of minimally invasive techniques, such a statement does not account for the many patient-specific nuances in spine surgery. These answers, which are often presented in a confident and convincing manner, highlight the necessity of exercising caution when using chatbots and maintaining a thorough understanding of their potential and limitations.

Conclusion AI has undoubtedly begun to transform patient communication in spine surgery, offering streamlined processes and enhanced information accessibility. However, the present integrations of AI must not substitute for the essential traditional patient-physician interaction, especially in areas requiring personalized communication such as informed consent. As AI continues to evolve, its synergistic use with human oversight will be key to maximizing its benefits in spine surgery. l

References 1. Cascella M, Montomoli J, Bellini V, Bignami E. Evaluating the feasibility of ChatGPT in healthcare: an analysis of multiple clinical and research scenarios. J Med Syst. 2023;47(1):33.

2. Subramanian T, Shahi P, Araghi K, et al.

Using artificial intelligence to answer common patient-focused questions in minimally invasive spine surgery. J Bone Joint Surg Am. 2023;105(20):1649-1653.

3. Lum ZC. Can artificial intelligence pass the American Board of Orthopaedic Surgery examination? Orthopaedic residents versus ChatGPT. Clin Orthop Relat Res. 2023;481(8):1623-1630.

4. Kuroiwa T, Sarcon A, Ibara T, et al.

The potential of ChatGPT as a self-diagnostic tool in common orthopedic diseases: exploratory study. J Med Internet Res. 2023;25:e47621.

5. Chatterjee S, Bhattacharya M, Pal S, Lee SS, Chakraborty C. ChatGPT and large language models in orthopedics: from education and surgery to research. J Exp Orthop. 2023;10(1):128.

6. Kesler K, Wynn M, Pugely AJ. Time and clerical burden posed by the current electronic health record for orthopaedic surgeons. J Am Acad Orthop Surg. 2022;30(1):e34-e43.

7. Shahi P, Vaishnav AS, Mai E, et al. Practical answers to frequently asked questions in

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minimally invasive lumbar spine surgery.

The Spine Journal. 2023;23(1):54-63.

8. Ayers JW, Poliak A, Dredze M, et al. Comparing physician and artificial intelligence chatbot responses to patient questions posted to a public social media forum.

JAMA Intern Med. 2023;183(6):589-596.

9. Andreotta AJ, Kirkham N, Rizzi M. AI, big data, and the future of consent.

AI Soc. 2022;37(4):1715-1728.

10. Weckbach S, Kocak T, Reichel H, Lattig F. A survey on patients’ knowledge and expectations during informed consent for spinal surgery: can we improve the shared decision-making process? Patient Saf Surg. 2016;10:15.

11. Jamoom EW, Heisey-Grove D, Yang N, Scanlon P. Physician opinions about EHR use by EHR experience and by whether the practice had optimized its EHR use. J Health Med Inform. 2016;7(4):1000240.

12. Shanafelt TD, Dyrbye LN, Sinsky C, et al. Relationship between clerical burden and characteristics of the electronic environment with physician burnout and professional satisfaction. Mayo Clin Proc. 2016;91(7):836-848.

13. Katsuura Y, Colón LF, Perez AA, Albert TJ, Qureshi SA. A primer on the use of artificial intelligence in spine surgery.

Clin Spine Surg. 2021;34(9):316-321.

14. McGuinness T, Nole D. Breaking new ground in healthcare with the next evolution of AI [blog]. Microsoft. March 21, 2023. https://blogs.microsoft.com/ blog/2023/03/20/breaking-new-ground-inhealthcare-with-the-next-evolution-of-ai/ 15. Harper K. The impact of technological advancements in healthcare [blog].

Nuance. April 10, 2023. https://whatsnext. nuance.com/healthcare-ai/transforming-medical-documentation-ai-technology/ 16. Pifer R. Amazon launches generative AI-based clinical documentation service. Healthcare Dive. July 26, 2023. https://www.healthcaredive.com/news/ amazon-generative-ai-clinical-documentation-healthscribe/688996/ 17. Suki. Suki Partners with Google Cloud [news release]. October 28, 2019. https://www.suki.ai/news/ suki-partners-with-google-cloud/ 18. Ali SR, Dobbs TD, Hutchings HA, Whitaker IS. Using ChatGPT to write patient clinic letters. Lancet Digit Health. 2023;5(4):e179-e181.

19. Garg RK, Urs VL, Agarwal AA, Chaudhary SK, Paliwal V, Kar SK. Exploring the role of ChatGPT in patient care (diagnosis and treatment) and medical research: a systematic review. Health Promot Perspect. 2023;13(3):183-191.

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BIG DATA

From 1the University of California Davis in Sacramento, California; 2The Ohio State University College of Medicine in Columbus, Ohio; and 3The Ohio State University College of Engineering in Columbus, Ohio.

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Preserving Privacy in Big Data Spine Surgery Research Exploring Federated Learning Solutions Hania Shahzad, MD1

In the dynamic landscape of spine surger y research, the burgeoning utilization of national databases and registries has endowed orthopedic spine surgeons w it h an unprecedented wealth of patient data. This influx of medical information, stemming from diverse diagnostic tools and integrated healthcare systems, forms the bedrock for informed decision-making in patient care. As treatment guidelines increasingly rely on patterns discerned from datasets, the accurate interpretation of these colossal data becomes imperative, inf luencing healthcare operations and patient outcomes. The surge in data and the need to reliably analyze the data has given rise to the fields of big data, data mining, machine learning, and predictive modeling.

What Are Big Data, Data Mining, and Machine Learning?

Big dat a refers to ex tensive a nd intricate datasets that are so large they require sophisticated software for interpretation, originating from diverse sources such as social media and business t ransact ions, char-

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acterized by high volume, variety, a nd velocit y. 1 Big data a na ly t ics extracts valuable insights, patterns, a nd k now le dge. Dat a m i n i ng i s a cr ucia l process w it hin t his domain, where meaningful patterns and correlations in large datasets are determined w it hout t he need for disclosing information that is deemed to be pr ivate. 2 Mach i ne learning (ML), a subset of artificial intelligence (AI), employs algorithmic approaches that enable machines to solve complex problems without explicit programming in medicine. In spine surgery, ML holds substantial promise for tasks such as diagnosis and outcome prediction where it can identify high-risk scenarios, offering potential insights into complications and revisions. 3,4 The computational process and data-driven nature of ML mark a t ransformat ive era in leveraging technology for improved postoperative outcomes.

What Is Predictive Modeling?

To combat rising healthcare costs and introduce value into the healthcare system, policymakers, surgeons,

Cole Veliky, BS2

Eugine Shin, BS3

Aylin Yener, PhD3

Safdar N Khan, MD1

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Figure 1. Diagrammatic representation of predictive modeling framework.

and public health scientists are increasingly applying AI to big data. Predictive modeling, a key component of this approach, integrates various outcome measures as dependent variables in clinical decision support tools using AI.5 Predictive modeling in healthcare and spine surgery develops models based on historical data to predict future patient outcomes or treatment responses based on historical patient data. 6

How Does Predictive Modeling Work?

Predict ive modeling beg ins w it h comprehensive data acquisition. The journey from data acquisition to model deployment involves several crucial steps. Patient data, including medical histor y, preoperative markers, surgical techniques, and postoperative outcomes, as well as radiographic imaging data, are meticulously gathered.

Electronic health records (EHRs) play a pivotal role in providing a holistic view of a patient’s health journey.

Local databases ser ve as repositories for storing pat ient data w it hin inst itu-

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tions. These databases are structured to facilitate easy access and analysis. Data preprocessing is initiated to clean and transform raw data into a format suitable for analysis. The ML model is then trained on a subset of the collected data, learning to recognize patterns, relationships, and features that correlate with specific outcomes in spine surger y. The model’s performance is rigorously validated using datasets not used during training, with iterative refinement based on feedback.

Once the model demonstrates satisfactory accuracy, it is deployed for real-time use, offering personalized predictions and decision support to spine surgeons.

Issues With Current Predictive Modeling in Spine Surgery The introduction of EHRs has made acquiring substantial medical data much easier, but it has also raised significant concerns regarding data protection and pr iv ac y. I nst a nces of hea lt hc a re dat a breaches affecting millions underscore the vulnerabilit y of private information

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BIG DATA

i n t hese dataset s. Cha l lenges a r ise i n ownership of data and in analyzing relevant portions of patient medical records approved by institutional review boards.

Collaborative efforts have established the creation of “data lakes,” serving as a unified source for training ML models and pooling data from multiple institutions.

Data lakes encourage collaboration while adhering to stringent patient confidentiality through encryption, access controls, and regular audits to maintain standards of optimum privacy regularities. However, without proper governance and structure, the management of data lakes poses significant challenges as well. In the context of spine surger y, developing AI models

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for tasks such as detecting anomalies or predicting outcomes requires extensive datasets. However, acquiring such data is challenging due to its sensitive nature and tight regulation. Even anonymization may not fully guarantee privacy; reconstruction of a patient’s face from CT or MRI data showcases this. Additionally, the meticulous curation and maintenance of high-qualit y healthcare data pose challenges, mak ing data collectors hesitant to freely share valuable datasets. These limitations in data sharing, compounded by biases in algorithms evaluated on selectively sourced datasets, underscore the necessity of exposing ML models to diverse cases for comprehensive understanding.

Figure 2. Diagrammatic representation of the machine learning vs federated learning paradigm.

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BIG DATA

The integration of predictive analytics has significantly advanced spine surgery research, offering unprecedented insights and opportunities for informed decisionmaking. However, challenges such as data privacy, security, and ethical considerations underscore the need for ongoing developments.

Federated Learning: A Solution to Privacy Concerns Fe der ate d lea r n i ng (F L) repre s ent s a pioneering approach in ML, specifically desig ned to add ress pr ivac y concer ns in predictive modeling.7 In FL, a central server trains an algorithm by collecting feedback from numerous sites where the program is operational. Unlike conventional ML models that aggregate data into a centralized location, FL permits local users to t rain a shared model collaboratively without sharing their raw data, preserving both security and privacy. The central server then consolidates updates from diverse local users, creating a global model. This global model is subsequently distributed to all local clients, initiating a cycle of refinement in each subsequent iteration. FL’s innovation lies in its capacity to leverage extensive data for ML without compromising the safet y and privacy of patient information. By prioritizing the sharing of algorithms over patient data, FL

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fosters substantial collaborations across institutions while mitigating privacy risks.

This methodolog y not only fortifies the efficacy of predictive modeling in spine surger y research but also establishes a precedent for secure and collaborative advancements in healthcare analytics. 8–10

Success stories FL has been used in medical research for predicting mortality, duration of hospital stays, and pre-term birth, as well as for performing a meta-analysis while concealing patient information, and most importantly allow ing for multicenter collaborations while ensuring data privacy.11 FL could have a significant impact on improving minimally invasive spine surgery.12–15 What the robot needs to learn, much like a good spine surgeon, is fine-tuned through repetition. FL can allow a robot to be trained on a model formulated from many more surgeries than one institution could ever prov ide, expediting t he learning cur ve g reat ly. T he robot s ca n be selec t ively trained on t he federated global model, benefiting from the surgeries performed at other institutions without exposing those patients to the potential breach of their private information. This would be highly beneficial in spine surgery procedures such as pedicle screw placement, where the efficacy of robots has been proven repeatedly, and newer applications such as deformity correction surgery and interbody fusion.16 Potential future applications in spine surgery include any procedure where precision and reproducibility are at a pre-

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mium, especially in the implementation of new techniques and procedures that would benefit from the rapid accumulation of trustworthy and secure data. This will allow spine surgery to stay on the cutting edge of medical science.

Conclusion In conclusion, the integration of predictive analytics has significantly advanced spine surgery research, offering unprecedented insights and opportunities for informed decision-making. However, challenges such as data privacy, security, and ethical consid-

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erations underscore the need for ongoing developments. The federated learning paradigm has the potential to utilize sensitive patient-related information to provide tailored management recommendations and enable collaboration among multiple organizations without sharing raw data, ensuring patient privacy while building a robust predictive model. Continued innovation in machine learning and federated learning holds the promise of furthering the integration of artificial intelligence into spine surgery research, ultimately shaping the future of personalized and data-driven healthcare. l

References 1. Pencheva I, Esteve M, Mikhaylov SJ. Big data and AI – a transformational shift for government: so, what next for research?

Public Policy Adm. 2020;35(1):24-44.

2. Haoxiang DW, Smys DS. Big data analysis and perturbation using data mining algorithm. J Soft Comput Paradigm. 2021;3(1):19-28.

3. Sidey-Gibbons JAM, Sidey-Gibbons CJ. Machine learning in medicine: a practical introduction. BMC Med Res Methodol. 2019;19(1):64.

4. Rajula HSR, Verlato G, Manchia M, Antonucci N, Fanos V. Comparison of conventional statistical methods with machine learning in medicine: diagnosis, drug development, and treatment.

Medicina (Mex). 2020;56(9):455.

5. Malik AT, Khan SN. Predictive modeling in spine surgery. Ann Transl Med. 2019;7(Suppl 5):S173.

6. Galbusera F, Casaroli G, Bassani T. Artificial intelligence and machine learning in spine research.

JOR SPINE. 2019;2(1):e1044.

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7. McMahan B, Moore E, Ramage D, Hampson S, Arcas BA y. Communication-efficient learning of deep networks from decentralized data. In: Proceedings of the 20th International Conference on Artificial Intelligence and Statistics.

PMLR. 2017:1273-1282. Accessed December 14, 2023. https://proceedings. mlr.press/v54/mcmahan17a.html 8. Xu J, Glicksberg BS, Su C, Walker P, Bian J, Wang F. Federated learning for healthcare informatics. J Healthc Inform Res. 2021;5(1):1-19.

9. Antunes RS, André da Costa C, Küderle A, Yari IA, Eskofier B. Federated learning for healthcare: systematic review and architecture proposal. ACM Trans Intell Syst Technol. 2022;13(4):54:1-54:23.

10. Nguyen DC, Pham QV, Pathirana PN, et al. Federated learning for smart healthcare: a survey. ACM Comput Surv. 2022;55(3):60:1-60:37.

12. Farhadi F, Barnes MR, Sugito HR, Sin JM, Henderson ER, Levy JJ. Applications of artificial intelligence in orthopaedic surgery. Front Med Technol. 2022;4.

13. Kurmis AP, Ianunzio JR. Artificial intelligence in orthopedic surgery: evolution, current state and future directions. Arthroplasty. 2022;4(1):9.

14. Lalehzarian SP, Gowd AK, Liu JN. Machine learning in orthopaedic surgery. World J Orthop. 2021;12(9):685699. doi:10.5312/wjo.v12.i9.685 15. Innocenti B, Radyul Y, Bori E. The use of artificial intelligence in orthopedics: applications and limitations of machine learning in diagnosis and prediction. Appl Sci. 2022;12(21):10775.

16. Wang TY, Park C, Dalton T, et al. Robotic navigation in spine surgery: where are we now and where are we going?

J Clin Neurosci. 2021;94:298-304.

11. Rahman A, Hossain MdS, Muhammad G, et al. Federated learning-based AI approaches in smart healthcare: concepts, taxonomies, challenges and open issues.

Clust Comput. 2023;26(4):2271-2311.

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TRAINING

From Midwest Orthopaedics at Rush in Chicago, Illinois.

Pain Interventionalists and Spine Surgery—Where Is the Line Drawn?

Chronic pain secondary to spine pathology is one of the leading contributors of national health expenditure and a common reason for physician office visits.1,2 The field of interventional pain Gregory Lopez, MD management originated in the late 20th century in response to this increasing burden of chronic pain on patients and the rising cost of healthcare.3 Interventional pain medicine is defined as a field of medicine devoted to the diagnosis and treatment of pain and related Ekamjeet Dhillon, MD disorders by the application of interventional techniques. These techniques can be broadly categorized into 3 main categories: injection therapy, neuromodulation, and percutaneous spine procedures.4 Injection therapy includes epidural steroid injections, transforaminal steroid injections, medial bundle branch blocks, and sacroiliac joint injections. These interventions grew by more than 200% in the early 2000s after the Center for Medicare & Medicaid Services published current procedure terminology (CPT) codes for procedures to be performed by interventionalists. 5,6 Neuromodulation includes insertion of spinal cord stimulation and radiofrequency ablation and similarly increased in popularity in the 2010s, especially after several randomized controlled trials supported their efficacy.5-7

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Percutaneous spine procedures include percutaneous image-guided lumbar decompression, stand-alone interspinous spacers, interspinous-interlaminar fusion, and sacroiliac joint fusion. These procedures were developed by multiple disciplines to address morbidity and complications associated with traditional spine surgery.8 However, they have recently been recognized as official interventional treatment modalities by the American Society of Pain & Neuroscience.4,7 In addition, they were intended to be used for patients in whom less invasive interventions, including PT, injection therapy, and neuromodulation, have failed. Unfortunately, they have been increasingly marketed as being first-line treatments for spine pathology.18 This has led to increasing criticism from surgical professional societies, which believe spinal instrumentation and arthrodesis should only be performed by spine surgeons.

Specialty overlap is not new in medicine or in the specialty of surgery. Hand procedures are performed by both plastic surgeons and orthopedic surgeons, with some peripheral nerve decompressions also performed by neurosurgeons. Vascular procedures, such as carotid endarectomies, are performed by general surgeons, neurosurgeons, and vascular surgeons.9 Facial procedures, such as rhinoplasties and facial fracture fixation, can be performed by plastic surgeons, otolaryngologists, and oral maxillofacial surgeons.10 Orthopedic surgeons specializing in foot and

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ankle often overlap procedures with podiatrists.

Although the type of subspecialist in each of these examples likely leads to minor differences in treatment decisions, surgical technique, and postoperative care, there is an expectation that these surgeons should receive training in their residencies and fellowships to be able to take care of any complications that may arise from the procedures they perform.

Although the introduction of these percutaneous decompression and fusion procedures allows interventionalists to perform procedures that were previously only performed by spine surgeons, there is concern that these procedures are being performed by interventionalists who may not be adequately trained to treat complications that arise from these procedures. This is largely because these percutaneous spine procedures are not listed in the ACGME’s list of interventional competencies for pain fellowship programs.11 As a result, there are no standardized case minimums for these procedures in pain fellowship training. Instead, fellowship programs are left on their own to determine whether training in these interventions should be a part of their curriculum. In fact, a 2018 survey reported that graduating and past fellows strongly supported direct training of pain fellows by implant companies as many learn these techniques through courses offered by these companies over the weekend.14 In contrast, spine surgeons have previously completed a residency in either neurosurgery or orthopedic surgery where they were required to perform a minimum number of spine decompressions and fusions. Furthermore, many spine surgeons follow their residency training with fellowship in spine surgery where they are

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exclusively performing procedures on the spine and are well equipped to treat complications that may arise from their index procedures.12,13 Due to the significant differences in the training between interventionalists and spine surgeons, the American Association of Neurological surgeons and Congress of Neurological Surgeons released a statement regarding the scope of interventionalists in 2021 that advocated for a clear delineation between surgery and intervention. They stated that “optimal patient care and patient safety are best served when surgical diseases affecting the spine are managed by neurosurgeons and orthopedic spinal surgeons trained in the full spectrum of spinal biomechanics, including instrumentation and fusion techniques.” They reiterated that the lack of formal surgical training in pain medicine fellowships prevents interventionalists from being able to appropriately manage surgical complications. This statement was endorsed by several other prominent spine surgery societies, including the American Academy of Orthopedic Surgeons, the Cervical Spine Research Society, and the International Society for the Advancement of Spine Surgery.15 A comparison of procedures that are currently being performed by both interventionalists and spine surgeons demonstrates differences in outcomes between specialties. A study comparing outcomes in patients undergoing kyphoplasty and vertebroplasty with either nonsurgical or surgical specialties found higher reoperation rates at 30 days for nonsurgeons.16 Another study looked at spinal cord stimulators implanted by interventionalists, and spine surgeons found higher trial-to-permanent conversion rates and fewer reoperations when

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performed by spine surgeons.17 These studies suggest that more invasive interventions, including percutaneous spine procedures, may be associated with fewer complications if performed by spine surgeons.

Interventional pain medicine has grown significantly over the past 3 decades, which has increased access of care and helped provide less invasive interventions for patients with chronic pain secondary to spine pathology. Injection therapy and neuromodulation are mainstays of

the field in both diagnosing and treating many spine pathologies and will continue to increase in volume according to recent trends. However, until there is an established system of providing education and measuring clinical competency in performing these more invasive percutaneous spine procedures, these should be considered as surgical interventions that are performed by or in conjunction with spine surgeons who feel comfortable in treating any complication that may arise from these procedures. l

References 1. Day M. Pain medicine: a medical specialty?

Pain Pract. 2004;4(1): 1–6, discussion 10.

2. Dieleman JL, Baral R, Birger M, et al.

US spending on personal health care and public health, 1996–2013. JAMA. 2016;316(24):2627–2646. https:// doi.org/10.1001/jama.2016.16885.

3. Hart LG, Deyo RA, Cherkin DC. Physician office visits for low back pain: frequency, clinical evaluation, and treatment patterns from a US national survey.

Spine (Phila Pa 1976). 1995;20(1):11–19.

4. Sayed D, Grider J, Strand N, et al. The American Society of Pain and Neuroscience (ASPN) evidence-based clinical guideline of interventional treatments for low back pain (published correction in J Pain Res. 2022;15:4075- 4076).

J Pain Res. 2022;6(15):3729–832.

5. Manchikanti L. The growth of interventional pain management in the new millennium: a critical analysis of utilization in the Medicare population.

Pain Physician. 2004;7(4):465–482.

6. Levinson DR. Medicare Payments for Facet Joint Injection Services. Department of Health and Human Services Office of Inspector General.

September 2008. https://oig.hhs.gov/ oei/reports/oei-05-07-00200.pdf 7. Naidu RK, Chaturvedi R, Engle AM, et al. Interventional spine and pain procedure credentialing: guidelines from the American Society of Pain & Neuroscience.

J Pain Res. 2021;8(14):2777–2791.

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8. Smith ZA, Fessler RG. Paradigm changes in spine surgery: evolution of minimally invasive techniques. Nat Rev Neurol. 2012;8(8):443–450.

14. Agarwal S, Cicone C, Chang P. Interventional pain procedures in physical medicine and rehabilitation residencies. Am J Phys Med Rehabil. 2018;97(4):298–303.

9. Enomoto LM, Hill DC, Dillon PW, Han DC, Hollenbeak CS. Surgical specialty and outcomes for carotid endarterectomy: evidence from the National Surgical Quality Improvement Program.

J Surg Res. 2014;188(1):339–348.

15. AANS Board of Directors and CNS Executive committee. Position Statement on Arthrodesis of the Spine by the Non-spine Surgeon. October 21, 2021. https:// www.aans.org/-/media/Files/AANS/ Advocacy/PDFS/AANS_and_CNS_Position_Statement_on_Arthrodesis_of_ the_Spine_FINAL-APPROVED_082121. ashx. Accessed December 24, 2023.

10. Doval AF, Ourian A, Boochoon KS, Chegireddy V, Lypka MA, Echo A. Comparing plastic surgery and otolaryngology surgical outcomes and cartilage graft preferences in pediatric rhinoplasty: a retrospective cohort study analyzing 1839 patients. Medicine (Baltimore). 2021;100(25):e26393.

11. Accreditation Council for Graduate Medical Education. ACGME Program Requirements for Graduate Medical Education in Pain Medicine. 2020. https://www.acgme. org/globalassets/pfassets/programrequirements/530_painmedicine_2023. pdf. Accessed December 21, 2023.

12. Silvestre J, Qureshi SA, Fossett D, Kang JD. Impact of spe- cialty on cases performed during spine surgery training in the United States. World Neurosurg.

2023;S1878–8750(23)00545–4. https:// doi.org/10.1016/j.wneu.2023.04.060.

13. 27. Daniels AH, DePasse JM, Magill ST, et al. The current state of United States spine surgery training: a survey of residency and spine fellowship pro- gram directors.

Spine Deformity. 2014;2(3):176–85.

16. Hogan WB, Philips A, Alsoof D, et al. Kyphoplasty and vertebroplasty performed by surgeons versus nonsurgeons: trends in procedure rates, complications, and revisions. World Neurosurg. 2022;164:e518–e524.

17. Babu R, Hazzard MA, Huang KT, Ugiliweneza B, Patil CG, Boakye M, Lad SP. Outcomes of percutaneous and paddle lead implantation for spinal cord stimulation: a comparative analysis of complications, reoperation rates, and health-care costs. Neuromodulation.

2013;16(5):418–426; discussion 426–427.

18. Staats PS, Hagedorn JM, Reece DE, Strand NH, Poree L. Percuta- neous image-guided lumbar decompression and interspinous spac- ers for the treatment of lumbar spinal stenosis: a 2-year Medicare claims benchmark study (published online ahead of print May 30, 2023). Pain Pract. 2023. doi:10.1111/papr.13256.

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From The CORE Institute in Phoenix, Arizona.

POLICY

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Healthcare Reform and Access to Spine Care in the United States During the past 2 decades, utilization of spine surgery in the United States has increased significantly.1 Many factors have contributed to this growth, among them the increasing age of the population, technological advances, and healthcare reform legislation.

Reform efforts during this time frame have primarily focused on increasing access to healthcare by increasing the proportion of insured patients in the US. After many attempts across multiple administrations, these efforts culminated in the landmark Affordable Care Act (ACA) in 2010.

While complex and controversial, the ACA achieved one of its primary goals in that it allowed a much larger proportion of the population to obtain insurance coverage.

In doing so, this legislation also increased access to subspecialty spine care. Greenberg et al studied a national database of more than 200,000 procedures bet ween 2011 and 2016 and found a 17% increase in spine surgical volume following enactment of the ACA. 2 A sub-analysis demonstrated a 23% increase in volume among patients with Medicaid insurance. While the ACA was successful in broadening coverage for Americans, much of the newly insured population still faces significant obstacles to accessing the healthcare they have now purchased. Two common characteristics of plans created by the ACA are significant

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cost sharing by beneficiaries (ie, high deductibles) and narrow prov ider net works. 3 As a result, these patients often find that they are “underinsured.”

This term refers to the fact that Brandon P. Hirsch, MD while they do have healthcare coverage, high deductibles make it too costly for them to use (beyond basic primary care) and they face limited choices with long wait times to access care.

In 2016, Segal et al conducted a study of 234 orthopedic spine practices across all 50 states to determine how patient’s payor category influenced their ability to obtain an appointment. Scripts describing fictitious patients with private insurance, Medicare, and Medicaid were used. Without a primary care provider (PCP) referral, 86% of callers with private insurance, 81% of callers with Medicare, and 0% of callers with Medicaid were given an appointment. When providing a PCP referral, these numbers improved to 99%, 95%, and 55% for private insurance, Medicare and Medicaid, respectively. A study by Anandasivam et al evaluated a similar question for a hypothetical patient seeking care for a lumbar disc herniation.

In this study, callers requesting an appointment w it h commercial insurance were given appointments at 95% of the offices that were contacted, whereas callers with

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POLICY

Medicaid callers were provided an appointment at only 0.8% of offices. When given an appointment, 93% of callers with Medicaid were required to obtain a referral, whereas 4% of callers with commercial insurance were asked to provide a referral.

These disparities in access and wait time for surgical treatment of spinal disorders have been demonstrated in real-world patient data. Durand et al analyzed the IBM MarketScan database with regard to the incidence and time to surgery for patients with diagnoses of cervical myelopathy and/ or radiculopathy.4 The authors compared patients with capitated plans (ie, HMO) vs high deductible and non–high deductible plans without capitation, including more than 750,000 patients. They found that pa-

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tients with capitated health plans were less likely to have had surgery for a diagnosis of myelopathy at 2 years from diagnosis when compared with non-capitated plans, regardless of deductible status. Patients with radiculopathy and a capitated plan had a sig nif icant ly lower likelihood of having surgery at 2 years post-diagnosis when compared to non-capitated patients.

Furthermore, among patients with non-capitated plans, those with a high-deductible plan were significantly less likely to have had surgery for radiculopathy than those in a non–hig h-deduct ible pla n 2 yea rs post-diagnosis. The authors found a similar impact of plan type on the time between diagnosis and surgery, with patients with capitated plans having the longest dura-

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POLICY

tion to surgery, followed by patients with high-deductible plans, followed by patients with non–high-deductible plans.

The findings of these studies are related in large part to several decades of reduction in professional fees that serve as the primary revenue source for spine surgery practices. As the largest payor in the US, Medicare’s professional fee schedule sets reimbursement levels for the majority of the patients in the US. This fee schedule is then used by commercial insurers as a benchmark to which their fee schedules are tied. A recent study of inf lation-adjusted reductions in Medicare reimbursement calculated an average decline of 26% in professiona l fees for common cer v ica l a nd lu mba r procedu res bet ween 2000 and 2020. 5 The declining reimbursement rates driven by these yearly reductions to the Medicare fee schedule continue to be a critical challenge for spine surgeons, prompting many to reconsider their participation in these government healthcare programs. As reimbursement rates continue to fall and the costs of operating a surgical practice continue to rise, spine surgeons find themselves grappling with financial

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constraints that impact the sustainability of their practices. These practices generally have two options to address this problem.

The first is acquisition by a large health system, which further increases healthcare consolidation and reduces competition. The other, increasingly popular, path is to opt out of federal healthcare programs. Both scenarios worsen the existing disparities in access to spine care in the US. The confluence of these factors underscores the urgent need for reform of the Medicare fee schedule to ensure that spine surgeons can sustain their practices while continuing to provide essential services to patients in need. The delicate balance between affordability for the healthcare system and fair compensation for medical professionals remains a major consideration in addressing the broader issues of healthcare accessibility and quality. Ongoing efforts by spine surgery specialty societies in Washington, DC, will be essential to bring this issue to the forefront in upcoming election cycles. Regardless of practice model, it will be important for spine surgeons and their patients to be politically active to preserve access to high quality spine care in the years to come. l

References 1. Badin D, Ortiz-Babilonia C, Musharbash FN, et al. Disparities in elective spine surgery for Medicaid beneficiaries: a systematic review. Global Spine J. 2023;13:534–546.

3. Sommers BD. Health care reform’s unfinished work—remaining barriers to coverage and access. N Eng J Med. 2015;373:2395-2397.

2. Greenberg JK, Brown DS, Olsen MA, et al. Association of Medicaid expansion under the Affordable Care Act with access to elective spine surgical care.

J Neurosurg Spine. 2021;36:336–344.

4. Durand WM, Ortiz-Babilonia C, Raad M, et al. Variation in commercial insurance type impacts access to cervical spine surgery.

Spine (Phila Pa 1976). 2023;48:1003-1008.

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5. Honarpisheh P, Parker SL, Conner CR, et al. 20-year inflation-adjusted Medicare reimbursements (years: 2000-2020) for common lumbar and cervical degenerative disc disease procedures.

Global Spine J. 2024;14:211.

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CLINICAL PRACTICE

From UCI Health in Orange County, California.

How to Handle Peer-to-Peer Calls One of t he most challeng ing and vexing issues that a surgeon may encounter are peer-to-peer calls. Such calls introduce an additional layer of complexity that surgeons must navigate to provide optimal care to patients.

Yu-Po Lee, MD Furthermore, these consultations necessitate our attention during the standard workday, posing a considerable inconvenience. Time, a finite and invaluable resource in our profession, becomes even scarcer due to the demands of peer-to-peer calls. Further exacerbating the issue, these calls may not yield a reversal of the original denial decision that prompted the call in the first place. These various factors collectively contribute to the frustration that often accompanies the handling of peer-to-peer consultations. However, by grasping a few pivotal concepts, we can facilitate a more streamlined approach to managing these calls.

The increasing prevalence of medical rev iews is driven by t he rising costs of healthcare, placing a significant strain on the healthcare system overall.1-3 Insurance companies and hospitals must figure out how to deliver the best possible care to the most patients with the limited budgets they have.4 However, wage growth has not kept pace with inflation, preventing insurance companies from raising premiums accordingly. This forces insurance companies to

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do more with less. In that environment, insurance companies must be more judicious with their budget because these companies must deliver the same quality of care despite the decreased purchasing power of the dollar. It is important to keep in mind that there is a reason why insurance companies are utilizing peer-to-peer calls and to recognize that many healthcare professionals are facing similar challenges when dealing with these calls.

To effectively handle peer-to-peer calls, it is crucial to understand the general criteria that insurance companies use for approving the procedure being discussed. Most insurance companies have a set criterion that patients must satisfy before they will approve the surgery. In most cases, nurses and physicians will provide the initial review and deny coverage if inclusion criteria are not met or exclusion criteria are identified.

For example, indications for lumbar fusion would include fracture, tumor, spondylolisthesis, or scoliosis. If a patient does not have any of these diagnoses, booking a patient for a fusion may result in denial or a peer-to-peer call. A commonly met exclusion criterion for fusion is smoking.

Therefore, making sure that your patients do not have any reasons for exclusion prior to scheduling their surgery will decrease the need for peer-to-peer calls. If a peer-to-peer is requested, it provides an opportunity to explain your rationale to another qualified

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surgeon. For instance, you may be able to proceed with an anterior cervical discectomy and fusion despite a patient being a smoker if the patient has severe stenosis and myelopathic findings. In this case, a peer-to-peer call allows you to clarify your reasoning and potentially gain support in overturning the denial.

Another important part of having a good outcome with peer-to-peer calls is to make sure that all the information that is required is provided. Instances of case denials often stem from missing MRI reports, incomplete documentation of nonoperative measures tried, or an unclear surgical plan. Retrieving imaging reports can be difficult to track down sometimes because patients may be coming from a different facility or city. However, these reports hold vital significance for insurance evaluations because they

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aid in whether a patient meets the criteria for surgery. Meticulous documentation of nonoperative treatments attempted and the precise surgical plan are important for risk management and for insurance approval. There is the old saying that if it is not in the medical record, then it was not done. In elective surgery cases, there is an expectation that patients with failed nonoperative treatments is why surger y was ultimately necessary. Therefore, documenting the nonoperative treatments will save surgeons the aggravation of having their cases denied. Leveraging electronic medical records and the use of templates with smart phrases should assist in ensuring the completeness of documentation and making it easier for surgeons. Additionally, if a L4-5 laminectomy and fusion is planned, then it should be documented as

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Meticulous documentation of nonoperative treatments attempted and the precise surgical plan are important for risk management and for insurance approval. There is the old saying that if it is not in the medical record, then it was not done. such so that the insurance companies can be sure to apply the appropriate codes to the cases so that you can be reimbursed properly. Simply stating that a patient has failed nonoperative treatment and is now ready for surgery will most likely lead to denial of the surgery because the insurance company cannot decipher whether the plan meets the requested codes.

Ensuring the accurate use of procedural codes is vital in navigating the world of coding and reimbursement that undergoes a n nua l rev isions. Stay ing in for mat ion rega rd i ng t hese updates is i mperat ive for surgeons. For instance, it is crucial to recognize that code 63047 is not the appropriate decompression code when used for a transforaminal lumbar interbody fusion

and will be denied if submitted despite a laminectomy being performed. Familiarity with the proper codes will decrease the likelihood of a surgery being denied. It is also best practice to keep up to date on coding rules to be sure that you are getting reimbursed fully for your work.

Furthermore, involv ing the patient is paramount as the ultimate beneficiary of these efforts is the patient. For instance, if a patient is a smoker, it can be very helpful to let them know that if they need a cervical fusion, their surgery will probably be denied if they do not commit to smoking cessation. Presurgical smoking cessation has demonstrated numerous positive effects on surgical outcomes. 5-6 In summary, several strategies exist for achieving favorable outcomes in peer-to-peer calls. Most important is recognizing that these calls provide an opportunity to present a compelling case to a peer regarding the benefit of the procedure to the patient. Adequate planning and adherence to coding is a crucial element of success with these calls. Ultimately, a patient’s well-being remains at the center of these efforts and makes it an essential component of achieving optimal outcomes in spine surgery. l

References 1. Bush M. Addressing the root cause: rising health care costs and social determinants of health. N C Med J. 2018;79(1):26-29.

2. Peeler AW. Strategies for cost saving through social determinants of health.

J Healthc Manag. 2019;64(4):222-230.

3. Sabatino MJ, Mick EO, Ash AS, Himmelstein J, Alcusky MJ. Changes in

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health care utilization during the first 2 years of Massachusetts Medicaid accountable care organizations. Popul Health Manag. 2023;26(6):420–429.

4. Zhou LL, Ampon-Wireko S, Brobbey EW, Dauda L, Owusu-Marfo J, Tetgoum ADK. The role of macroeconomic indicators on healthcare cost. Health-

care (Basel). 2020 May 4;8(2):123.

5. Berman D, Oren JH, Bendo J, Spivak J. The effect of smoking on spinal fusion. Int J Spine Surg. 2017;11(4):29.

6. Khurana VG. Adverse impact of smoking on the spine and spinal surgery. Surg Neurol Int. 2021;12:118

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Drs. Lorio and Tumialán are members of the ISASS Executive Board of Directors.

ISASS COMMUNICATION

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Aetna’s Policy Threatens Patient Choice and Clinical Excellence As an organization deeply committed to advancing spine surgery and advocating for the best interests of spine patients, we, the International Society for the Advancement of Spine Surgery (ISASS), along with Disorders of the Spine and Peripheral Nerves, feel compelled to address a pressing issue that has significant ramifications for both the medical community and the patients we serve. It is a matter of grave concern that Aetna, a prominent health insurance provider, has chosen to apply downward pressure on the standard of care for cervical arthrodesis—a decision that not only

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impacts spine surgeon choice but also undermines clinical best practices, disregards patient-consumer choice, and neglects the diversity of cultural preferences.

The complex landscape of cervical ar t hrodesis, a surg ical procedure aimed at spinal f usion to address various cervical spine conditions, has been subject to ongoing debate and research. In the midst of this discussion, one critical choice remains: the selection of cage-spacers, specifically between allografts and synthetic cages.

The spine literature is equally divided

Morgan P. Lorio, MD

Luis M. Tumialan, MD

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on this matter, inf luenced largely by the heterogeneous use of bone graft fillers as adjuncts rather than the type of cage chosen.

However, the distinction becomes clear when we examine the outcomes. Synthetic cages, as opposed to structural allografts, offer a means to reliably restore cervical lordosis and biomechanical stability that is superior to what is achievable with crude structural allografts. In essence, synthetic cages make the work of a spine surgeon more effective, enabling us to provide our patients with optimal care.

This is where the issue with Aetna’s reimbursement policy arises. Currently, CPT code 20931, which is used to report the placement of structural allografts during cervical arthrodesis, is limited to a single use, regardless of the number of allografts required in the same surgical session. In contrast, CPT code 22853, designated exclusively for cage use, offers higher reimbursement and may be reported for each inner space where a cage is employed.

The result is a financial disincentive for surgeons to choose sy nt het ic cages, as some payers, including Aetna, consider “spine cages NOT medically necessary for cervical fusion.”

This policy not only presents a financial burden for surgeons but, more importantly, it limits the surgeon’s ability to make decisions in the best interest of their patients.

By creating a financial incentive to favor allografts, which may not always be the most appropriate choice for a given patient, insurers like Aetna are compromising the doctor-patient relationship and the overall qualit y of care that patients receive.

Patient choice is being undermined, and their access to the latest advancements in spinal surgery is at risk.

In the ever-evolving field of spine surgery, it is crucial that healthcare policies align with clinical best practices and the preferences of patients and their surgeons.

Aet na’s cu r rent rei mbu rsement pol ic y does the opposite. It stif les innovation, restricts surgeon choice, and jeopardizes the well-being of spine patients.

We ca l l upon Aet na to reconsider its policy and recognize that synthetic cages can be a vital part of cervical arthrodesis, fostering better outcomes and promoting t he highest standards of care. Patients deserve nothing less than the best, and we, their spine surgeons, should have the freedom to make decisions that ref lect the latest advancements in our field.

In closing, we encourage Aetna to revisit its stance on this issue, ensuring that it aligns with the principles of patient choice, clinical excellence, and a commitment to advancing the field of spine surger y for the benefit of all those who entrust their health to our care. l

References 1

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Singh K, Qureshi S. ISASS policy statement – cervical interbody. Int J Spine Surg. 2014;8:13.

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