Vertebral COLUMNS 2022SUMMER International Society for the Advancement of Spine Surgery SHIFT IN USAGE OF SurgicalAmbulatoryCenters FOR SPINE SURGERY INSIDE Stem Cells ForaminotomyPosteriorEndoscopicPolicyMalpracticeAboutShouldSpineCorner:MedicolegalSurgeryImagingIntraoperativeTheSpineUpperDiscDegenerativeinDiseaseCervicalFracturesFutureofinSpineWhatSurgeonsKnowTheirCervical PLUS
Vertebral Columns is published quarterly by the International Society for the Advancement of Spine ©2022Surgery.ISASS. All rights reserved. Opinions of authors and editors do not necessarily reflect positions taken by the Society. This publication is available digitally at columns-Summer-2022www.isass.org/news/vertebralEditor in Chief Kern Singh, MD Editorial Board Peter Derman, MD, MBA Brandon Hirsch, MD Sravisht Iyer, MD Yu-Po Lee, MD Sheeraz Qureshi, MD, MBA Managing Editor Audrey Lusher Designer CavedwellerStudio.com2118151173 isass.orgSpring 2022 Vertebral Columns EDITORIAL Shift in Usage of Ambulatory Surgical Centers for Spine Surgery BIOLOGICS Stem Cells in Degenerative Disc Disease TRAUMA Upper Cervical Spine Fractures LOOKING FORWARD The Future of Intraoperative Imaging in Spine Surgery BUSINESS Medicolegal Corner: What Spine Surgeons Should Know About Their Malpractice Policy ENDOSCOPY Endoscopic Posterior Cervical Foraminotomy: Stealth Surgery for the Treatment of Cervical Radiculopathy todayaBecomemember https://www.isass.org/about/membership/
EDITORIAL
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Kern Singh, MD Eileen Zheng, BS Keith R. MacGregor, BS Omolabake O. Oyetayo, BS
Timothy J. Hartman, BS James W. Nie, BS
Patient Selection Patient selection remains essential in minimizing risk of poor outcomes and complications in the ASC. One study of 708 patients eligible for outpatient spine surgery proposed patient se lection criteria for performing spine surgery in the ASC. 8 These criteria considered proximity of 30 minutes to a hospital, body mass index (BMI) <42 kg/m 2 , medical clearance in patients with chronic conditions, clearance from a cardiologist in patients with heart disease, ability for a caretaker to be present for at least 24 hours after surgery, and an American Society of Anesthesiologists (ASA) classification of less than or equal to 3. 8 A sepa rate study utilized a Delphi panel to determine safe patient selection in performing ACDF and CDR in the
5–7 Advancements in minimally invasive techniques have permitted more complex procedures in the ASC setting, such as multilev el lumbar fusion and 3-level ACDF. 5 Adoption of nonfusion techniques, such as cervical disc replacement (CDR), have also introduced new types of procedures performed in the ASC.
In 2018, more than 23 million surger ies were performed in an ambulatory surgical center (ASC) in the United States. 1,2 Many of these surgeries consisted of cataract, arthroscopic, peripheral nerve, or soft tissue cases.1–3 In comparison to these other proce dures, spine surgery has historically comprised a smaller proportion of am bulatory procedures. 3 However, with an estimated cost of $90 billion per year in the diagnosis and management of low back pain, performing spine surgery safely in the ASC has become an increasingly promising method of cost reduction. 3,4 During the previous 2 decades, anterior cervical discectomy and fusion (ACDF), lumbar decompres sion, and single-level lumbar fusion comprised the majority of ASC-based spine procedures.
From the Department of Orthopedic Surgery, Rush University Medical Center, 1611 W Harrison St, Chicago, Illinois.
This article examines the emergence of patient selection criteria in ambulatory spine surgery, ASC-based cervical and lumbar procedures, postoperative pain management, and future directions of performing spine surgery in the ASC.
Shift in Usage of Ambulatory Surgical Centers for Spine Surgery
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Cervical Surgery
Multiple studies have compared the safety profile and clinical outcomes of patients undergoing ambulatory versus hospital ACDF. Most of these studies concluded that performing outpatient ACDF is safe and has similar clinical outcomes compared to the hospital setting. 3,12–17 However, these studies noted that patients should be observed 4-6 hours postoperatively to monitor for neck hematoma and airway compromise. 3,16 With the adoption of nonfusion techniques over the past 2 decades, CDR has become an alternative procedure in treating discogenic pathologies of the cervical spine.18 In articles comparing CDR versus ACDF, multiple stud ies reported that patients undergoing CDR demonstrated similar to superior clinical outcomes of pain, physical function, and disability.18–21 Furthermore, patients under going CDR had preserved range of motion, decreased adjacent segment disease, and decreased dysphagia, and they were less likely to undergo further surgery.18 In the outpatient setting, one study of 26 patients undergoing CDR in the ASC reported no complications or readmissions. 22 A separate
The senior author’s (K.S.) patient selection criteria considers similar factors.10 Specifi cally, age older than 65 years, BMI >40 kg/ m 2 , elevated risk of postoperative nausea and vomiting, functional dependence, inacces sibility of a reliable caregiver at home, and presence of severe medical comorbidities (eg, congestive heart failure, myocardial infarction within 6 months, angina, ASA ≥3, elevated risk of thromboembolism, or obstructive sleep apnea) are factors that preclude patients undergoing surgery in the ASC.10 Operative considerations that may preclude patients from undergoing surgery in the ASC include operative duration greater than 2 hours, increased surgical invasiveness, and spinal deformity.10 The criteria proposed and Delphi panel indicate the biopsychosocial factors, comorbidities, and operative factors that must be considered when selecting patients for the ambulatory setting.
4 isass.orgSpring 2022 Vertebral Columns EDITORIAL ASC. 9 Here, the panel consensus determined that patients with severe cardiopulmonary comorbidities of a New York Heart Associ ation class of III-IV, myocardial infarction within 6 months, severe angina, and/or ASA classification of 4 should preclude patients from undergoing surgery at an ASC. 9
From 1994 to 2006, ACDF comprised 5% to 17% of all spine cases performed in the ASC. 7 In 2014, 30% of ACDF procedures were performed in the outpatient setting.11
retrospective cohort study of 55 patients comparing single-level CDR against ACDF in the ASC reported no serious complications within 90 days of surgery, no incidence of hematoma formation, and significantly improved clinical outcomes.
5 isass.org Spring 2022Vertebral Columns EDITORIAL
Looking Forward Although performing spine surgery in the ASC is promising as an effective cost-reduction strategy and a method of improving value-based care, consideration of the patient’s comorbidities and support system and the operative complexity must be considered prior to intervention.
Advancements in minimally invasive techniques and nonfusion techniques have shifted the landscape of ASC-based spine surgery to involve more complex procedures and to introduce alternative surgical interventions. As additional studies continue to confirm the safety, efficacy, and decreased economic burden of these procedures in the hands of an experienced spine surgeon, the ambu latory setting will likely continue to see an increase in the frequency of common cervical and lumbar procedures. n
“Consideration of the patient’s comorbidities and support system and the operative complexity must be considered prior to intervention.”
23 Although current review of the literature for CDR in the ASC remains limited, the benefits of CDR along with initial safety assessments suggest increasing adoption of this surgical technique in the ASC. Lumbar Fusion In the lumbar spine, lumbar decompres sion was one of the earliest procedures transitioned to the ambulatory setting and remains the most common spine procedure performed in the ASC. 3,5 Prior studies have consistently demonstrated favorable clini cal outcomes and safety profile in patients undergoing lumbar decompression in the ASC. 3,5,24–27 The introduction of minimally invasive surgical techniques has increased the utilization and viability of performing ASC-based lumbar fusion. 3,5 First introduced in the early 2000s, the minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) represents 1 minimally inva sive technique performed in the ASC. 28,29 In comparison to the open approach, patients undergoing MIS-TLIF had less postoperative pain, decreased postoperative narcotic us age, lower estimated blood loss, and shorter length of stay. 30–32 In addition, the lateral lumbar interbody fusion (LLIF) represents a different minimally invasive technique that has been performed in the outpatient setting. 33,34 Several articles examining MISTLIF and LLIF in the ASC reported that these lumbar fusion procedures may be performed safely in the ambulatory setting and demonstrate favorable clinical out comes. 5,10,33,34 Despite the limited number of studies, performing lumbar fusion in the ASC has become increasingly feasible.
5. Gerling MC, Hale SD, White-Dzuro C, et al. Ambulatory spine surgery. J Spine Surg. 2019;5:S147–S153.
9. Mohandas A, Summa C, Worthington WB, et al. Best practices for outpatient anterior cervical surgery: results from a Delphi Panel. Spine . 2017;42:E648–E659.
11. Idowu OA, Boyajian HH, Ramos E, Shi LL, Lee MJ. Trend of spine surger ies in the outpatient hospital setting versus ambulatory surgical center. Spine . 2017;42:E1429–E1436.
33. Smith WD, Wohns RNW, Christian G, Rodgers EJ, Rodgers WB. Outpatient minimally invasive lumbar interbody: fusion predictive factors and clinical results. Spine . 2016;41 (suppl 8):S106–S122.
20. Zigler JE, Delamarter R, Murrey D, Spivak J, Janssen M. ProDisc-C and anterior cervical discectomy and fusion as sur gical treatment for single-level cervical symptomatic degenerative disc disease: five-year results of a Food and Drug Admin istration study. Spine . 2013;38:203–209.
2. Hall MJ, Schwartzman A, Zhang J, Liu X. Ambulatory surgery data from hospitals and ambulatory surgery centers: United States, 2010. Natl Health Stat Report . 2017;1–15.
3. Pendharkar AV, Shahin MN, Ho AL, et al. Outpatient spine surgery: defining the outcomes, value, and barriers to imple mentation. Neurosurg Focus . 2018;44:E11.
24. Helseth Ø, Lied B, Halvorsen CM, Ekseth K, Helseth E. Outpatient cervical and lumbar spine surgery is feasible and safe: a consecutive single center se ries of 1449 patients. Neurosurgery 2015;76:728–737; discussion 737–738.
30. Hammad A, Wirries A, Ardeshiri A, Nikiforov O, Geiger F. Open versus minimally invasive TLIF: literature review and meta-analy sis. J Orthop Surg Res . 2019;14:229. 31. Kim CH, Easley K, Lee JS, et al. Compar ison of minimally invasive versus open transforaminal interbody lumbar fusion. Global Spine J. 2020;10:143S–150S.
34. Chin KR, Pencle FJR, Coombs AV, et al. Lateral lumbar interbody fusion in ambu latory surgery centers: patient selection and outcome measures compared with an inhospital cohort. Spine . 2016;41:686–692.
10. Parrish JM, et al. Outpatient mini mally invasive lumbar fusion using multimodal analgesic management in the ambulatory surgery setting. Int J Spine Surg. 2020;14:970–981.
8. Chin KR, Pencle FJR, Coombs AV, Packer CF, Hothem EA, Seale JA. Eligi bility of outpatient spine surgery candi dates in a single private practice. Clin Spine Surg. 2017;30:E1352–E1358.
16. Lied B, Sundseth J, Helseth E. Immediate (0-6 h), early (6-72 h) and late (>72 h) com plications after anterior cervical discecto my with fusion for cervical disc degenera tion; discharge six hours after operation is feasible. Acta Neurochir. 2018;150:111–118.
18. Findlay C, Ayis S, Demetriades AK. Total disc replacement versus anterior cervi cal discectomy and fusion: a systematic review with meta-analysis of data from a total of 3160 patients across 14 random ized controlled trials with both shortand medium- to long-term outcomes. Bone Joint J. 2018;100-B:991–1001.
26. Asch HL, Lewis PJ, Moreland DB, et al. Prospective multiple outcomes study of outpatient lumbar microdiscectomy: should 75 to 80% success rates be the norm? J Neurosurg. 2002;96:34–44.
6. Gray DT, Deyo RA, Kreuter W, et al. Popu lation-based trends in volumes and rates of ambulatory lumbar spine surgery. Spine 2006;31:1957–1963, discussion 1964.
27. Pugely AJ, Martin CT, Gao Y, Men doza-Lattes SA. Outpatient surgery reduces short-term complications in lumbar discectomy: an analysis of 4310 patients from the ACS-NSQIP database. Spine . 2013;38:264–271. 28. Foley KT, Lefkowitz MA. Advances in minimally invasive spine surgery. Clin Neurosurg. 2002;49:499–517.
EDITORIAL
23. Chin KR, Pencle FJR, Seale JA, Pencle FK. Clinical outcomes of outpatient cervical total disc replacement compared with outpatient anterior cervical discectomy and fusion. Spine . 2017;42:E567–E574.
22. Wohns R. Safety and cost-effective ness of outpatient cervical disc arthro plasty. Surg Neurol Int . 2010;1:77.
25. Best NM, Sasso RC. Success and safety in outpatient microlumbar discectomy. J Spinal Disord Tech. 2006;19:334–337.
12. Walid MS, Robinson JS 3rd, Robinson ERM, Brannick BB, Ajjan M, Robinson JS Jr. Com parison of outpatient and inpatient spine surgery patients with regards to obesity, comorbidities and readmission for infec tion. J Clin Neurosci. 2010;17:1497–1498.
13. Silvers HR, Lewis PJ, Suddaby LS, Asch HL, Clabeaux DE, Blumenson LE. Day surgery for cervical microdiscectomy: is it safe and effective? J Spinal Disord. 1996;9:287–293.
19. Janssen ME, Zigler JE, Spivak JM, Delamarter RB, Darden BV 2nd, Kopjar B. ProDisc-C total disc replacement versus anterior cervical discectomy and fusion for single-level symptomatic cervical disc disease: seven-year follow-up of the prospective randomized U.S. Food and Drug Administration Investiga tional Device Exemption study. J Bone Joint Surg Am. 2015;97:1738–1747.
14. Trahan J, Abramova MV, Richter EO, Steck JC. Feasibility of anterior cervical discec tomy and fusion as an outpatient proce dure. World Neurosurg. 2011;75:145–148.
29. Basques BA, Ferguson J, Kunze KN, Phillips FM. Lumbar spinal fusion in the outpatient setting: an update on manage ment, surgical approaches and planning. J Spine Surg. 2019;5:S174–S180.
32. Qin R, Wu T, Liu H, Zhou B, Zhou P, Zhang X. Minimally invasive versus traditional open transforaminal lumbar interbody fusion for the treatment of low-grade degenerative spondylolisthesis: a retro spective study. Sci Rep. 2020;10: 21851.
7. Best MJ, Buller LT, Eismont FJ. Na tional trends in ambulatory surgery for intervertebral disc disorders and spinal stenosis: a 12-year analysis of the National Surveys of Ambulatory Surgery. Spine . 2015;40:1703–1711.
17. Sheperd CS, Young WF. Instrumented outpatient anterior cervical discectomy and fusion: is it safe? Int Surg. 2021;97:86–89.
21. Delamarter RB, Murrey D, Janssen ME, et al. Results at 24 months from the prospec tive, randomized, multicenter Investiga tional Device Exemption trial of ProDisc-C versus anterior cervical discectomy and fusion with 4-year follow-up and continued access patients. SAS J. 2010;4:122–128.
15. Lied B, Rønning PA, Halvorsen CM, Ekseth K, Helseth E. Outpatient ante rior cervical discectomy and fusion for cervical disk disease: a prospec tive consecutive series of 96 patients. Acta Neurol Scand. 2013;127:31–37.
1. Young S, Pollard RJ, Shapiro FE. Pushing the envelope: new patients, pzrocedures, and personal protective equipment in the ambulatory surgical center for the COVID-19 Era. Adv Anesth. 2021;39:97–112.
4. Martin BI, Deyo RA, Mirza SK, et al. Expenditures and health status among adults with back and neck prob lems. JAMA . 2008;299:656–664.
6 isass.orgSpring 2022 Vertebral Columns References
Basic Science Findings
Degenerative disc disease (DDD) is one of the more common causes of chronic low back pain, disc herniation, spinal stenosis, and paresthe sia. In fact, more than 90% of adults aged 50 years old and up have disc degeneration,1 often resulting in a significant decrease in quality of life. Current treatments for DDD include either conservative or surgical approaches, both of which aid in relieving the symptoms of ongoing disc degeneration. Intervertebral discs are complicated structures, and disc de generation is usually a multifactorial process that may involve many different aspects of the disc. Because these current approaches fail to treat the underlying degenerative etiology, the clinical outcomes can vary. Biological approaches to the treatment of DDD have therefore become a field of increasing inter est. Therapies including platelet-rich plasma, protein injections, gene therapies, and stem cells have all been researched to varying clinical success.
2 Stem cells are undifferentiated and therefore can mature into a variety of specialized cells. Because of the vast possibilities, employing stem cell therapy (SCT) has become one of the fastest emerging fields in medicine. Mes enchymal stem cells (MSCs) are a subset of nonhematopoietic stem cells that can be found in bone marrow and adipose tissue. These cells can differentiate into a variety of cells within the mesenchymal lineage, including chondrocytes, adipocytes, and osteoblasts. Because of the variety of terminal differentiation pathways for these cells as well as the relative ease of extraction, culture, and use, MSCs have become very popular thera peutic tools. 3 Within the realm of degenerative spinal pathologies, these therapies hold great prom ise in treatment, whereas current treatment modalities remain mostly ineffective. In this review we discuss both the basic science and clinical literature in SCT for the treatment of DDD.
Tejas Subramanian, BE Eric Zhao, BS Sravisht Iyer, MD
BIOLOGICS
The therapeutic potential of MSCs in DDD comes from the differ entiation into cells with the ability to pro liferate within intervertebral discs, increase extracellular matrix (ECM) remodeling, and inhibit inflammation. In the basic science literature, cell and animal models have shown very promising results. Yang et al studied MSCs’ ability to arrest disc degeneration in a mouse model.4 The stem cells underwent chondrocytic differentiation within the disc and increased autonomous differentiation of notochordal cells, resulting in regeneration of the nucleus pulposus (NP) with upregulation of extracellular matrix promoting factors.4 In a rat model, Ekram et al found that MSCs differentiated into functional NP cells, which Stem Cells in Degenerative Disc Disease
From the Hospital for Special Surgery (Mr Subramanian, Mr Zhao, and Dr Iyer) and the Weill Cornell Medical College (Mr Subramanian and Mr Zhao), both in New York, New York. All authors contributed equally to this article.
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Despite its gradual onset in clinical practice, applications of stem cell transplantation in treating DDD have shown promising results. Treatment often involves the injection of either autologous or allogeneic stem cells into the symptomatic disc, which can be a less invasive alternative to surgery. In a study conducted by Pettine et al, 26 patients were referred for surgical consultation but opted for autologous bone marrow MSC injections at either 1 or 2 affected levels. 9 Throughout the 12-month follow-up, no adverse events were reported, and 21 out of 26 patients demonstrated statis tically significant improvements in pain and disability based on the visual analog scale (VAS) and the Oswestry Disability Index (ODI).9
In another study by Kumar et al, 10 chronic low back pain patients were followed for 12 months following disc injections of autologous adipose-derived MSCs. ODI, VAS, 36-Item Short Form Survey (SF-36), and magnetic resonance imaging (MRI) were used to track patient progress.10 At 6 months, 7 patients had achieved greater than 50% reductions in VAS and ODI, which was sustained through 12 months in 6 of the patients.10 Adipose MSCs
The basic science literature across medicine is ripe with promising results for the use of MSCs in the treatment of pathologies. We have described just some of these results for the treatment of DDD in animal models. However, there has generally been a slow adoption of these therapies in clinical practice. In the next section we will look at the preliminary clinical results utilizing MSC therapy for treatment of DDD in humans.
8 isass.orgSpring 2022 Vertebral Columns BIOLOGICS also downregulated various pain and inflam mation genes. 5 Wang et al investigated one of the therapeutic mechanisms.6 Certain aberrant miRNA pathways have been implicated in disc degeneration and NP cell apoptosis. 6 They found that MSCs upregulate and activate the miR-101-3p/EIF4G2 axis, thereby promoting ECM remodeling and repair in degenerated discs.6 Biglycan is another important com ponent of the ECM; when it is deficient, it has been shown to lead to the progression of degenerative discs.7 Marfia et al found that by implanting MSCs into degenerative discs of biglycan-deficient mice, disc damage was improved and biglycan expression was increased.7 Studies have also analyzed pain and “clinical” outcomes in animal models utilizing stem cells for treatment of DDD. In a study of 4 canines with DDD presenting with chronic spinal cord injury, Penha et al treated them with MSCs. 8 Each of the dogs demonstrated symptomatic improvements over time.8 Within 10 days after the procedure, they experienced recovery of the panniculus reflex and decreased pain response. 8 By 18 months, the researchers observed significant clinical improvements, including improved movement.8
Preliminary Clinical Results
Another similar study by Elabd et al followed 5 patients with DDD for 4 to 6 years after treatment with autologous bone marrow MSCs.13 The authors found that all patients reported overall improvement based on quality-of-life questionnaires and improvements in strength and mobility in 4 out of 5 patients.13 Zero adverse events were reported during the treatment and follow-up period, and no neoplasms were noted based on MRI imaging.13
In addition to autologous cell transplants, transplants of allogeneic stem cells and nucleus pulposus (NP) cells are also possible treatments for DDD. While studies of allogeneic stem cell transplants are less common, Noriega et al demonstrated that DDD patients who received allogeneic stem cell treatment experienced significant improvements in VAS and ODI at months 3, 6, and 12 that were not reported in the control group.14 The MSC-treated group also reported improvements in disc degeneration as measured by the Pfirrmann scale, while the control group experienced worsening disc degeneration.14 Transplantation of nucleus pulposus cells is also an option for treating DDD by reducing inflammation and producing proteoglycans and collagen—2 components of healthy disc tissue. Mochida et al found that when autologous NP cells are co-cultured with autologous bone marrow MSCs, the MSCs were able to increase the viability and proliferation of NP cells in vitro.15 Additionally, out of 9 patients with Pfirrmann’s grade III disc degeneration treated with NP cells pre viously co-cultured with MSCs, average low back pain scores and Japanese Orthopaedic Association (JOA) clinical symptom scores both improved, and no further worsening of disc health was noted in any patient during the 3-year follow-up period.15
While the study reported positive outcomes, it is limited by its small sample size and lack of randomization.
Additional considerations in SCT are the ability of the transplanted cells to survive over time and the long-term safety of transplant ed stem cells. One study by Henriksson et al reported that stem cells were able to survive in a degenerated intervertebral disc environ ment 8 months after transplantation.11 These transplanted cells differentiated into chondro cyte-like cells and were dispersed throughout the disc.11 These cells also stimulated native disc cells to produce ECM components, which may contribute positively to the health of de generated discs.11 Indeed, transplanted stem cells in the long term may continue to help with symptom reduction in DDD. In a pilot study of 33 patients with DDD conducted by Centeno et al, patients were followed for up to 6 years after receiving autologous bone mar row MSCs.12 Patient-reported outcomes were measured using net promoter score (NPS), modified single assessment numeric evalu ation (SANE) rating, functional rating index (FRI), and intervertebral disc measurements.12 In addition to there being no serious adverse events, post-transplant NPS reductions at months 3, 36, 48, 60, and 72 were significant relative to baseline.12 Improvements in SANE scores and FRI were also noted at multiple time points, and 17 of the 20 patients who opted to undergo MRI experienced an average disc bulge reduction of 23%.12
9 isass.org Spring 2022Vertebral Columns BIOLOGICS are also harvested via a less-invasive process compared to bone marrow MSCs, and they produce a larger number of viable cells.10
References
J Transl Med. 2017;15(1):197.
1. Cheung KMC, Karppinen J, Chan D, et al. Prevalence and pattern of lumbar magnetic resonance imaging changes in a population study of one thousand forty-three individ uals. Spine . 2009;34(9):934940. BRS.0b013e3181a01b3fdoi:10.1097/
7. Marfia G, Campanella R, Navone SE, et al. Poten tial use of human adipose mesenchymal stromal cells for intervertebral disc regeneration: a preliminary study on biglycan-deficient murine model of chronic disc degeneration. Arthritis Res Ther. 2014;16(5):457.
4. Yang F, Leung VY, Luk KD, Chan D, Cheung KM. Mes enchymal stem cells arrest intervertebral disc degener ation through ofdifferentiationchondrocyticandstimulationendogenouscells. Mol Ther. 2009;17(11):1959-1966.
6. Wang Z, Ding X, Cao F, Zhang X, Wu J. Bone mesenchymal stem cells promote extracel lular matrix remodeling of degenerated nucleus pulpo sus cells via the miR-101-3p/ EIF4G2 Axis. Front Bioeng Biotechnol. 2021;9:642502.
Disc degeneration is a highly common oc currence with aging, and symptomatic disc degeneration can be a painful and debili tating cause of chronic low back pain. SCT has the potential to be an effective surgical adjuvant or nonsurgical treatment option for patients; however, safety and ethical factors must be taken into consideration. Though studies of MSC therapy have generally been safe, MSCs can still undergo malignant transformations when exposed to a tumor microenvironment.16 Additionally, the field of SCT is saturated with ethical dilemmas, including—but not limited to—donation of biological tissue, use of different stem cell sources, and weighing of risks and balances of SCT, all of which must be careful navigated if SCT is to grow in impact.17 Overall, SCT has shown great promise in treating DDD, and while the studies mentioned above have shown encouraging results, larger random ized double-blind studies are needed to further explore this field of great potential.
10. Kumar H, Ha DH, Lee EJ, et al. Safety and tolerability of in tradiscal implantation of com bined autologous adipose-de rived mesenchymal stem cells and hyaluronic acid in patients with chronic discogenic low back pain: 1-year follow-up of a phase I study. Stem Cell Res Ther. 2017;8(1):262.
J Transl Med. 2016;14:253.
16. Zhang YM, Zhang ZM, Guan QL, et al. Co-culture with lung cancer A549 cells promotes the proliferation and migration of mesenchy mal stem cells derived from bone marrow. Exp Ther Med 2017;14(4):2983-2991.
12. Centeno C, Markle J, Dod son E, et al. Treatment of lumbar degenerative disc disease-associated radicular pain with onstemautologousculture-expandedmesenchymalcells:apilotstudysafetyandefficacy.
2. Moriguchi Y, Alimi M, Khair T, et al. Biological treatment approaches for degenerative disk disease: a literature review of in vivo animal and clinical data. Glob Spine J. 2016;6(5):497-518.
17. Lo B, Parham L. Ethical issues in stem cell research. Endocr Rev. 2009;30(3):204-213.
9. Pettine KA, Murphy MB, Suzuki RK, Sand TT. Percutaneous injection of autologous bone marrow concentrate cells significantly reduces lumbar discogenic pain through 12 months. Stem Cells Dayt Ohio. 2015;33(1):146-156.
10 isass.orgSpring 2022 Vertebral Columns BIOLOGICS Additional Considerations
5. Ekram S, Khalid S, Bashir I, Salim A, Khan I. Human umbili cal cord-derived mesenchymal stem cells and their chondro progenitor derivatives reduced pain and inflammation signal ing and promote regeneration in a rat intervertebral disc de generation model. Mol Cell Bio chem. 2021;476(8):3191-3205.
11. Henriksson HB, Papadimitri ou N, Hingert D, Baranto A, Lindahl A, Brisby H. The trace ability of mesenchymal stro mal cells after injection into degenerated discs in patients with low back pain. Stem Cells Dev. 2019;28(17):1203-1211.
n
15. Mochida J, Sakai D, Nakamura Y, Watanabe T, Yamamoto Y, Kato S. Intervertebral disc repair with activated nucleus pulposus cell transplantation: a three-year, prospective clinical study of its safety. Eur Cell Mater. 2015;29:202212; discussion 212.
14. Noriega DC, Ardura F, Hernández-Ramajo R, et al. Intervertebral disc repair by allogeneic mesenchymal bone marrow cells: a randomized controlled trial. Transplanta tion. 2017;101(8):1945-1951.
13. Elabd C, Centeno CJ, Schul tz JR, Lutz G, Ichim T, Silva FJ. Intra-discal injection of autologous, hypoxic cul tured bone safetylowerfivemesenchymalmarrow-derivedstemcellsinpatientswithchronicbackpain:along-termandfeasibilitystudy.
3. Minguell JJ, Erices A, Conget P. Mesenchymal stem cells. Exp Biol Med Maywood NJ 2001;226(6):507-520.
8. Penha EM, Meira CS, Guim arães ET, et al. Use of autolo gous mesenchymal stem cells derived from bone marrow for the treatment of naturally in jured spinal cord in dogs. Stem Cells Int . 2014;2014:437521.
Atlanto-Occipital Dislocations
2 Occipital Condyle Fractures
Upper Cervical Spine Fractures
The upper cervical spine has a unique anatomy to help provide the majority of the range of motion of the cervical spine. The upper cervical spine, which consists of the occiput to C3 bones and joints, provides more than half of the flexion, extension, and rotation of the cervical spine. 1 The bony anatomy of the upper cervical spine protects the spinal cord and the vertebral artery in this transitional area between the skull and spine. To allow this motion, the upper cervical spine is dependent on ligamentous integrity for mechanical sta bility. As a result, the upper cervical spine is prone to injury. Upper cervical spine injuries are potentially devastating inju ries that spine surgeons must understand in order to provide appropriate treatment. This article will highlight the classifica tions and treatments for atlanto-occipital dislocation (AOD), occipital condyle frac ture, atlas fractures, C2 fractures, and C2 pars interarticularis fractures (Hangman’s fracture).
Occipital condyle fractures are uncommon injuries usually re sulting from high-energy blunt trauma. They are considered a type of basilar skull fracture and can be seen along with craniocervical dissociation.
Treatment of isolated occipital condyle fractures is generally conservative, unless there is craniocervical junction instability. The Anderson and Montesano classification is used for describing occipi tal condyle fractures based on morpholog ical variation and is separated into three categories: type I fractures are described as impacted-type occipital condylar fractures with little to no displacement of fragments 3 ; type II fractures involve extension of the condylar fracture to the basilar skull with out loss of ligamentous integrity 3 ; and type III fractures are classified as inferomedial avulsion-type injuries of the occipital condyle with potential loss of stability due to concomitant injury of the contralateral alar ligament and tectorial membrane.
3
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From UCI Health in Orange County, California. TRAUMA Sohaib Hashmi, MD Yu-Po Lee, MD
Atlanto-occipital dislocations are highly unstable, often fatal injuries arising from the osseoligamentous disruption of the major stabilizers of the atlanto-occipital joint. There is injury to the alar ligaments, the tectorial membrane, and the atlan to-occipital joint capsule. Treatment is surgical with occipital cervical instrumentation and fusion, usually occipital-C1 or occipi tal-C2 posterior instrumented fixation.
4 Isolated anterior or posterior arch fractures are the most common. Iso lated burst fractures are the second most commonly seen C1 fracture. Neurological injury, while rare, may occur if the burst fracture expands into the spinal canal. The treatment of C1 fractures is based on whether they occur in isolation or in com bination with other cervical spine injuries.
Figure 1 Figure 2 Figure 3
12 isass.orgSpring 2022 Vertebral Columns TRAUMA Atlas Fractures Atlas (C1) fractures are generally the result of high-energy trauma, such as from falls or motor vehicle accidents. The mechanism is generally due to hyperextension or axi al loading.
C2 Fractures
4 The type of surgical fixation is determined by the presence of any concurrent occipitocervical injuries.
8
Common mechanisms of injury include motor vehicle accidents, diving injuries, or falls from significant height in younger patients with high bone mineral density. In older patients, lower energy events, such as ground-level falls, may result in a similar pattern of injury.
7
8 Developed in 1974, Anderson and D’Alonzo developed a classification system of 3 types of C2 fracture, described by increasing severity:
• Type 1: avulsion fracture of the rostral tip of the odontoid
Also, treatment is based on the integrity of the transverse ligament. Isolated atlas fractures without injury of the transverse ligament or bony avulsion of the transverse ligament can be treated with bracing. Sur gical fixation is recommended if there is disruption of the transverse ligament or if instability is present.
There are several classification systems for atlas fractures. The Jefferson classifi cation is the most commonly used scheme in the United States and is separated into four types: type 1 and 2 fractures involve isolated injury to the posterior or anterior arches, respectively; type 3 fractures are a combination of types 1 and 2, involving injury to both the anterior and posterior arches; and type 4 fractures are classified as either unilateral or bilateral injury to the lateral mass or masses of the C1 vertebra. 5,6 Treatment of atlas fractures is dependent on the stability of the atlantodens interval (ADI). An ADI interval <3 mm (<5 mm in children) is normal, 3-5 mm represents injury to the transverse ligament with intact alar and apical ligaments, and >5 mm represents injury to the transverse ligament, alar ligament, and tectorial membrane.
• Type 3: fracture through the body of the C2 vertebrae Hard collar or halo immobilization is recommended for types 1 and 3 odontoid fractures. In patients with type 2 odontoid fractures, a hard collar is recommended in patients who are older than 80 years or who are poor surgical candidates. With hard collar management, patients risk de velopment of a fibrous nonunion; however, not all of the fibrous nonunions will go on to develop a symptomatic nonunion. 9 A posterior C1-2 fusion is recommended for C2 fractures in patients who are able to undergo surgery or have late dysfunction.10
First described in 1910 by Mixter and Os good, fractures of the C2 dens, known as odontoid fractures, are typically the result of high-energy trauma to the cervical spine, resulting in forced hyperextension.
• Type 2: fracture through the waist of the odontoid process
One additional measure of stability is measuring the displacement of the C1 lateral masses, where a displace ment >6.9 mm may indicate a transverse ligament injury. Treatment of stable type 1, 2, and 3 fractures includes use of a hard collar or halo immobilization for 6 to 12 weeks. For unstable type 2 and 3 fractures, treatment involves posterior C1-2 fusion or occipitocervical fusion.7
13 isass.org Spring 2022Vertebral Columns TRAUMA
C2
14 isass.orgSpring 2022 Vertebral Columns TRAUMA
Type Description Treatment 1 <3 mm subluxation of C2 on C3. Conservative management with rigid cervical collar 2 Disruption of the C2 to C3 disc, >4 mm subluxation, greater than 11° angulation <5 mm requires reduction and halo fixation for 6-12 weeks while >5 mm may require surgery
Bilateral fracture of the pars interarticu laris of C2 is commonly referred to as a Hangman’s fracture. These injuries are relatively common cervical spine fractures. Several fracture classifications have been proposed. However, atypical Hangman’s fracture variants may cause spinal canal compromise rather than canal expansion. The atypical Hangman’s variants often have coronal or sagittal plane fractures of the posterior body of the dens. This fragment may cause neurological deficits with this injury (Figure 1).11 A summary of the Levine and Edwards classification and management of Hangman’s fracture is provided in the Table. n
References
7. Kim D, Viswanathan VK, Menger RP. C1 Fractures . StatPearls Publishing. 2022. 8. Pryputniewicz DM, Hadley MN. Axis fractures. Neurosurgery. 2010;66:68–82.
6. Kontautas E, Ambrozaitis KV, Kales inskas RJ, Spakauskas B. Management of acute traumatic atlas fractures. J Spinal Disord Tech. 2005;18:402–405.
5. Landells CD, Van Peteghem PK. Fractures of the atlas: classification, treatment and morbidity. Spine . 1988;13:450–452.
4. Kandziora F, Scholz M, Pingel A, et al. Treatment of atlas fractures: rec ommendations of the Spine Section of the German Society for Ortho paedics and Trauma (DGOU). Global Spine J. 2018;8(2 suppl):5S–11S.
9. Tenny S, Varacallo M. Odontoid Frac tures . StatPearls Publishing. 2022.
2a Less displacement than type 2 but with more angular deformity Treatment in a halo fixation or surgical management 3 C2 to C3 facet capsule disrupted, anterior longitudinal ligament also disrupted Surgical treatment may be necessary; options include C2-3, anterior cervical discectomy and fusion, isolated C2 fixation, C1-2 posterior fusion, or C1-3 posterior fusion depending on integrity of the C2-3 disc and facets (Figures 2 and 3)
1. Whitcroft KL, Massouh L, Amirfeyz R, Bannister G. Comparison of methods of measuring active cervical range of motion. Spine . 2010;35:E976–E980.
3. Anderson PA, Montesano PX. Morphol ogy and treatment of occipital condyle fractures. Spine . 1988;13:731–736.
Pars Interarticularis Fracture (Hangman’s Fracture)
10. Hsu WK, Anderson PA. Odontoid frac tures: update on management. J Am Acad Orthop Surg. 2010;18:383–394. 11. Murphy H, Schroeder GD, Shi WJ, et al. Management of Hangman’s frac tures: a systematic review. J Orthop Trauma. 2017;31(suppl 4):S90–S95.
Table. Levine and Edwards Classification and Management of Hangman’s Fracture
2. Joaquim AF, Schroeder GD, Vaccaro AR. Traumatic atlanto-occipital dislocation-a comprehensive analysis of all case series found in the spinal trauma literature. Int J Spine Surg. 2021;15:724–739.
for Special Surgery in New York, New York. LOOKING FORWARD
The ability to objectively determine the amount of tissue removal, correctly position different implants, and assess the degree of deformity correction are only a few of the many advan tages that imaging techniques have provided. These techniques have ultimately allowed spine surgeons to track the position of surgical instruments, provide multiplanar views of the anatomy, and aid in preoperative planning.2
The Future of Intraoperative Imaging in Spine Surgery
From Hospital
the
15 isass.org Spring 2022Vertebral Columns
There is ongoing research to improve the intra operative imaging modalities in spine surgery that can eventually improve patient outcomes.2 Spine surgeries have transitioned from the use of radiography, ultrasonography, com puted tomography (CT), magnetic resonance imaging (MRI), and fluoroscopy to various types of navigation and robotic systems.1,2 Yet, more recently, the use of machine-learning algorithms, augmented reality systems, and virtual reality systems are becoming more scrutinized and seem to be paving the way for future modalities.3 This article gives a brief overview of the possible future of intraoperative imaging in spine surgery. Machine Learning Machine-learning algorithms are codes created in an artificial intelligence (AI) computer pro gram that can perform various tasks based on any data provided by an investigator.4 Numer ous algorithms, which range from simply labeling vertebral levels on patients to AI-guided pedicle screw placement, have already been cre ated.5 In 2017, one study created an AI capable of identifying vertebral levels and intervertebral discs in 96% to 97% of cases.6 In a separate study, an algorithm was created capable of enhancing radiographic files for increased image resolution that was able to provide automatic conversion of various imaging modality files (eg, radiography to MRI and MRI to CT).7 Further studies demonstrated a pedicle screw algorithm system that could properly suggest screw entry points with 95.4% accuracy in patients undergoing corrective deformity surgery with Cobb angles less than 75%.8 Notably, their entire algorithm was able to create these projections at a mean of 11 seconds.8 These self-learning computers are of great interest in spine surgery because they can facilitate better surgical planning, aid in the prediction of postoperative alignment, and provide computerized consistency among treatments. Although the use of such tools con tinues to be time-consuming, as the amount of available data for these machine-learning algorithms increases, their capabilities will exponentially increase as well.9
Intraoperative imaging has played a vital role in spine surgery over the past several decades.1
Robert Kamil, BS Pratyush Shahi, MBBS, MS Sheeraz(Ortho)A. Qureshi, MD, MBA
A recent prospective clinical trial of 20 patients undergoing AR-guided spinal fixation reported an overall thoracic pedicle screw accuracy level of 94.1%. Another study reported that AR was helpful for ACDF and posterior cervical laminotomy and foramino tomy.12 Kosterhon et al utilized AR to visu alize resection planes of an intraoperative osteotomy in a live spinal deformity patient to determine whether it could help increase accuracy and patient safety.13 Ultimately, the authors determined that surgeons benefit ted from the display and were able to turn the display off if it was ever found to be too distracting. While AR prototype systems are still continuously being developed, their wide range of applications in spine surgery should certainly be anticipated in the coming years.
LOOKING FORWARD
Virtual Reality Interactive feedback-based virtual reality (VR) systems have recently moved to the forefront of spine surgery. VR has been proven to aid with surgical training, preoperative planning, and complex spinal deformity cases. The main benefit of the VR concept is the opportunity to improve one’s surgical technique while minimizing the possibility of mistakes and often reducing costs. Gasco et al compared the performance of a group of medical students utilizing traditional visual and verbal instructions for lumbar pedicle screw placements in sawbones with another group of medical students utilizing a VR simulator for the same task. The study concluded that the simulation group out performed the traditional learning group in all variables, including trajectory, depth of screw error, and breach. 14 The results were attributed to sequential learning, en hanced depth perception, and increased 3D anatomical understanding.14 Similarly, Gottschalk et al provided further credence to the applicability of VR through a blinded, randomized controlled trial that examined whether VR helped orthopedic residents improve lateral mass screw insertion in the cervical spine of cadavers and sawbones.15 It was found that the residents significant ly improved when previously trained with VR.15 Complementary to VR training, more recent efforts have tried expanding the uses of VR into the practice of experienced spine surgeons.16Zhouetal combined VR with navigation for minimally invasive lumbar transforam inal microdiscectomy and had the same surgeon place L3–S1 screws on the left side of a cadaver without the use of VR and nav igation, then had them do a VR simulation for surgical planning and place screws on the right side.17 The VR-planned side was
Augmented reality (AR) systems allow the projection of virtual 3-dimensional (3D) images onto a user’s real-time view of the surgical field. The current commercial prototypes that exist have improved the efficiency of instrumentation placement in fusion surgeries, increased patient safety outcomes, optimized ergonomics in the surgical suite, and ultimately lowered var ious procedural costs.10
Current published literature on AR-guided navigation for spine surgery has explored the application of AR for pedicle screw fixation, anterior cervical discectomy and fusion (ACDF) procedures, and spinal deformity cases with promising results.10,11
16 isass.orgSpring 2022 Vertebral AugmentedColumnsReality
n LOOKING FORWARD
7. Galbusera F, Bassani T, Casaroli G, et al. Generative models: an upcoming innovation in mus culoskeletal radiology? A pre liminary test in spine imaging. Eur Radiol Exp. 2018;2(1):29.
J Am Acad Or thop Surg. 2014;22(12):800-809.
14. Gasco J, Patel A, Ortega-Barnett J, et al. Virtual reality spine surgery simulation: an empirical study of its usefulness. Neurol Res. 2014;36(11):968-973.
9. Lafage R, Pesenti S, Lafage V, Schwab FJ. Self-learning computers for surgical planning and prediction of postoper ative alignment. Eur Spine J 2018;27(suppl 1):123-128.
The future of intraoperative imaging in spine surgery is exciting. The clear applicability of machine-learning algorithms, AR proto types, and VR-based simulators has been rapidly growing and has certainly shown very promising results. As research on these different prototypes continues to expand, their wide utilization should be expected to increase in the very near future.
8. Burström G, Buerger C, Hop penbrouwers J, et al. Machine learning for automated 3-di mensional segmentation of the spine and suggested placement of pedicle screws based on intraoperative cone-beam com puter tomography. J Neurosurg Spine. 2019;31(1):147-154.
13. Kosterhon M, Gutenberg A, Kan telhardt SR, Archavlis E, Giese A. Navigation and image injection for control of bone removal and osteotomy planes in spine surgery. Oper Neurosurg (Hag erstown). 2017;13(2):297-304.
Conclusion
11. Yoo JS, Patel DS, Hrynewycz NM, Brundage TS, Singh K. The utility of virtual reality and augmented reality in spine surgery. Ann Transl Med. 2019;7(Suppl 5):S171.
15. Gottschalk MB, Yoon ST, Park DK, Rhee JM, Mitchell PM. Surgi cal training using three-dimen sional simulation in placement of cervical lateral mass screws: a blinded randomized control tri al. Spine J. 2015;15(1):168-175.
19. Lafage R, Bess S, Glassman S, et al. Virtual modeling of post operative alignment after adult spinal deformity surgery helps predict associations between compensatory spinopelvic alignment changes, overcor rection, and proximal junctional kyphosis. Spine (Phila Pa 1976) 2017;42(19):E1119-E1125.
1. Qureshi S, Lu Y, McAnany S, Baird E. intraoperativeThree-dimensionalimagingmodalitiesinorthopaedicsurgery:anarrativereview.
4. Bajwa A. Artificial intelli gence vs robotics vs machine learning vs deep learning vs data science. Medium. March 11, 2021. datadriveninvestor.com/https://medium. artificial-intelligence-vs-ro ta-science-70ff828cdf39ing-vs-deep-learning-vs-dabotics-vs-machine-learn
10. Yanni DS, Ozgur BM, Louis RG, et al. Real-time navigation guidance with intraoperative CT imaging for pedicle screw placement using an augmented reality head-mounted display: a proof-of-concept study. Neu rosurg Focus. 2021;51(2):E11.
Another study explored the use of VR for comparing preoperative and postoperative imaging of patients with adult spinal deformity.19 They demonstrated that the use of VR for 3D reconstruction greatly benefitted the assessment and decision-mak ing processes.19 VR has demonstrated better preoperative planning in minimally invasive spinal procedures and should be anticipated to be in more spine training modules and complex spine cases in the near future.
6. Forsberg D, Sjöblom E, Sunshine JL. Detection and labeling of vertebrae in MR images using deep learning with clinical anno tations as training data. J Digit Imaging. 2017;30(4):406-412.
17 isass.org Spring 2022Vertebral Columns found to have better exposure and punc ture-to-channel times.17 Similarly, Zheng et al compared percutaneous endoscopic lumbar discectomies with and without preoperative VR planning for thirty randomized patients and found improved location timing when VR planning was used.18
References
5. Harada GK, Siyaji ZK, Younis S, Louie PK, Samartzis D, An HS. Imaging in spine surgery: current concepts and future directions. Spine Surg Relat Res. 2019;4(2):99-110.
12. Mascitelli JR, Schlachter L, Chartrain AG, et al. Naviga tion-linked heads-up display in intracranial surgery: early ex perience. Oper Neurosurg (Hag erstown). 2018;15(2):184-193.
16. Yuk FJ, Maragkos GA, Sato K, Steinberger J. Current innova tion in virtual and augmented reality in spine surgery. Ann Transl Med. 2021;9(1):94.
17. Zhou Z, Hu S, Zhao YZ, et al. Feasibility of virtual reality combined with isocentric navigation in discectomy:percutaneoustransforaminalendoscopicacadaverstudy. Orthop Surg. 2019;11(3):493-499.
18. Zheng C, Li J, Zeng G, et al. Development of a virtual reality preoperative planning system for postlateral endoscopic lumbar discectomy surgery and its clinical application. World Neurosurg. 2019;123:e1-e8.
2. Nimsky C, Carl B. Historical, cur rent, and future intraoperative imaging modalities. Neurosurg Clin N Am. 2017;28(4):453-464.
3. Yuk FJ, Maragkos GA, Sato K, Steinberger J. Current innova tion in virtual and augmented reality in spine surgery. Ann Transl Med. 2021;9(1):94.
From The Core Institute in Mesa, Arizona.
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Corner
3
The frequency of claims and high dollar value of adverse judgments tend to make malpractice insurance costly for spine surgeons. In a 2012 study, 70% of respondents in a large survey reported that they spend more than 10% of their gross annual practice revenue on premiums. 4
2
What Spine Surgeons Should Know About Their Malpractice Policy
Malpractice claims are common occurrences for spine surgeons, with an estimated annual inci dence between 14% and 19%. 1
BUSINESS
Brandon P. Hirsch, MD
Professional liability insurance is generally structured as either an “occurrence” or a “claims-made” policy. Occurrence policies cover claims made for any event that oc curred during the period that the policy was in effect, regardless of when a claim was filed. Occurrence policies tend to have significantly higher premiums and have become uncom mon. The majority of physician malpractice policies in effect today are “claims-made” policies. These policies will cover claims only if they are made during the period of coverage AND if the event pertaining to the claim also occurred during the time that the policy was in effect. Coverage under claimsmade policies may end at the termination of the policy or may include what is known as “tail-coverage” that covers claims for a set period of time after the policy ends. Surgeons who are changing practices (or insurance carriers) must be aware of how their policy is worded in this regard, as they will often be required to arrange their own “tail-cov erage” or ensure that their new practice has arranged to provide this coverage.
The quantity of coverage offered in a li ability policy is particularly important for spine surgeons to be aware of given the large dollar amounts typically associated with settlements and defense verdicts in the field.
Although spine surgeons often prevail in malpractice litigation, set tlements and plaintiff’s verdicts can involve large sums. A recent analysis of 103 cases found an average settlement amount of $2.4 million with an average plaintiff’s verdict of $3.9 million.
Despite its importance, most surgeons receive minimal education on the pertinent aspects of malpractice insurance during training. With the continued trend toward surgeon employment or its variants, many spine surgeons are now covered by policies that were chosen on their behalf by a larger entity, further limiting their familiarity with policy details.
Despite the frequency of claims related to spine surgeons, ver dicts in favor of the plaintiff are uncommon, with a 2018 analysis of the Westlaw database reporting that more than 71% of cases being decided in the de fendant’s favor.
MedicolegalColumns
Referred to as “policy limits,” these values are typically expressed as both a per-claim
It is also important to understand whether your policy provides the right to select your own counsel. Commonly, insurers assign attorneys on behalf of the insured. Cases involving spine surgery tend to involve mul tiple co-defendants (assistant, anesthesia, neuromonitoring technician/physician, employer, hospital), sometimes covered by the same insurance carrier. In these sce narios, co-defendants are often assigned the same firm or attorney to reduce cost to the carrier. In cases involving multiple co-defendants, conflicts of interest may exist in the representation of each party.
19 isass.org Spring 2022Vertebral Columns BUSINESS amount and an aggregate annual amount. When settlements or verdicts exceed these thresholds, the insured are responsible for the remaining amount. Most carriers offer a standard limit of $1 million per claim and $3 million aggregate annual coverage. In some scenarios, it may be advantageous for spine surgeons to have higher policy limits. Many factors, some of which are state-specific, can affect this decision. Sur geons should consult with a knowledgeable insurance agent or experienced colleague when determining how much coverage to obtain. It is also important to understand whether legal fees are considered “inside” or “outside” the policy limits. When defense costs are considered inside the policy lim its, they are included in the total coverage offered by the policy, reducing the amount the insurer will pay toward a settlement or defense verdict. Policies where defense costs apply outside the limits are advantageous in that they do not reduce coverage amounts due to legal fees.
Defense strategies that are advantageous to the hospital may not be advantageous to the surgeon. Such conflicts can be harmful to a defendant’s case and should always be avoided. While a clause specifying the right to select counsel ensures this right, it is not necessarily required in order to obtain independent representation. When a conflict of interest becomes evident, it is important to express this in writing, to both the attorney and the insurer. Attorneys are ethically bound to recuse themselves from representing a party when these conflicts exist. Failure to do so runs the risk of in curring additional liability for legal mal practice or being sanctioned by the state bar
Anotherassociation.important feature in a liability pol icy is a clause that protects the right to refuse settlement. In essence, this clause prevents the insurer from electing to settle the case
Malpractice liability in spine surgery is a complex and constantly evolving topic. A basic understanding of liability policy struc ture and content is useful to all spine sur geons, perhaps more so than physicians in any other specialty. Due to the potential for large plaintiff’s judgements, spine surgeons should be aware of their policy limits and consider whether they are adequate. Clauses protecting the right to choose counsel and the right to refuse settlement can be very important components of a liability policy, particularly in cases involving multiple or corporate co-defendants. Spine surgeons can save tremendous cost, frustration, and potential reputational harm by taking the time to investigate these aspects of a policy in advance of encountering a malpractice claim. n
1. Jena AB, Seabury S, Lak dawalla D, et al. Malpractice risk according to physician specialty. N Engl J Med 2011;365:629–636.
“Due to the potential for large plaintiff’s judgements, spine surgeons should be aware of their policy limits and consider whether they are adequate. Clauses protecting the right to choose counsel and the right to refuse settlement can be very important components of a liability policy, particularly in cases involving multiple or corporatedefendants.”co-
References
20 isass.orgSpring 2022 Vertebral Columns without your consent. For many defendants, a settlement is preferable to proceeding to trial and risking a jury verdict that exceeds policy limits. While settlements may not involve financial cost to the defendant, they can still have other untoward effects on a spine surgeon’s career. The National Practi tioner Data Bank (NPDB) is a federal online database of adverse actions taken against healthcare professionals. The database contains state medical board complaints, sanctions levied by professional societies, licensure revocation or restriction, and all plaintiff’s judgments and malpractice set tlements on a physician’s behalf. While an individual listing in the database may not be problematic, multiple occurrences can affect a physician’s ability to obtain future employment and/or professional liability coverage. Preserving the right to refuse settlement allows the surgeon to control whether or not their case will appear in the NPDB, which in many cases is more valuable than the outcome of the claim itself.
2. Agarwal N, Gupta R, Agarwal P, et al. Descriptive analysis of state and federal spine sur gery malpractice litigation in the United States. Spine (Phila Pa 1976). 2018;43:984–990. 3. Makhni MC, Park PJ, Jimenez J, et al. The medicolegal landscape of spine surgery: how do surgeons fare? Spine J. 2018;18:209–215. 4. Nahed BV, Babu MA, Smith TR, et al. Malpractice liability and defensive medicine: a national survey of neurosurgeons. PLoS One . 2012;7:e39237.
BUSINESS
The operative technique is likewise similar to open or tubular PCF. My technique is briefly described as follows:
Peter B. Derman, MD, MBA
The benefit of the endoscopic approach extends beyond simply preservation of the paraspinal soft tissues, however. The angled optics of the endoscope facilitate viewing deeper within the foraminal space, and the narrow endoscop ic cannula can be directed in a more medial-to-lateral trajectory before abutting the spinous process than can a conventional tubular retractor. Both of these features permit more extensive under cutting of the facet joint, which allows for adequate expansion of the foraminal area while minimizing the degree of facet joint resection and may reduce the incidence of postoperative segmental hypermobility.
The surgical indications for endoscopic PCF are identical to those established for open or tubular approaches: foraminal ste nosis due to disc herniation and/or osseous overgrowth in the absence of significant central stenosis, instability, or deformity.4
From Texas Back Institute in Plano, Texas.
21 isass.org Spring 2022Vertebral Columns
Posterior cervical foraminotomy (PCF) with or without discectomy is a well-established treatment for cervical radiculopathy. Unlike anterior cervical discectomy and fusion (ACDF), the traditional gold standard sur gical treatment, PCF allows for nerve root decompression without the need for instru mentation and without sacrificing motion. It has been studied extensively and has been found to have clinical outcomes that are generally comparable to ACDF.1–3 One barrier to the more widespread utili zation of PCF may be the increased muscle spasm, neck pain, and blood loss associated with open posterior approaches to the cer vical spine.4,5 However, the development of less invasive techniques has decreased ap proach-related morbidity and made PCF a more appealing option than it had been in the past. Minimally invasive tubular approaches produce similar degrees of symptomatic relief to open foraminotomy but with less blood loss, immediate postoperative neck pain, analgesic use, and hospital length of stay.6,7 Endoscopic techniques allow surgeons to perform PCF in an even more atraumatic fashion. As might be expected, full-en doscopic PCF produces shorter hospital stays and less postoperative neck pain than other techniques without sacrificing clinical effectiveness. 8,9
ENDOSCOPY
Endoscopic Posterior Cervical Foraminotomy Stealth Surgery for the Treatment of Cervical Radiculopathy
the
• The patient is positioned prone on a Jackson frame with the head resting on a foam head holder and the arms down by the patient’s sides. Cranial traction is not employed.
8
22 isass.orgSpring 2022 Vertebral Columns ENDOSCOPY
• The disc space can be explored and herniated disc fragments removed with a micro-pituitary rongeur, if Visualizationpresent. during an endoscopic PCF tends to be excellent for a number of rea sons. Modern endoscopic systems feature Figure posteriorthecalallyIntraoperative1.photographlookingmeditowardthesacduringaleftC6-7endoscopiccervicalforaminotomy.
• After fluoroscopic localization and infiltration of local anesthetic, an 8-mm longitudinal paramedian skin and fascial incision is made overlying the laminar facet junction on the side of the approach in line with the disc space at the operative level.
• The medial border of the facet joint (known as the “interlaminar V”) is identified.
The superior articular process of the caudal vertebra can be undercut to further expand the foraminal dimensions without sacrificing an additional facet joint. Decompression should span from cranial to caudal pedicle and to the lateral margin of these pedicles.
• A burr and Kerrison rongeur are used to complete the dorsal decompression as they would be open—the medial approximately one-third of the inferior and superior articular processes are resected, unroofing the foramen and revealing the exiting nerve root (Figure 1).
• Sequential dilators, followed by the working cannula and endoscope, are inserted.
5. Skovrlj B, Gologorsky Y, Haque R, Fessler RG, Qureshi SA. Complications, out comes, and need for fusion after minimally invasive posterior cervical foraminotomy and microdiscectomy. Spine J. 2014;14(10):2405-2411.
ENDOSCOPY
6. Kim KT, Kim YB. Comparison between open procedure and tubular retractor assisted procedure for cervical radiculopathy: results of a randomized controlled study. J Korean Med Sci. 2009;24(4):649-653.
7. Winder MJ, Thomas KC. Minimally in vasive versus open approach for cervical laminoforaminotomy. Can J Neurol Sci. 2011;38(2):262-267.
9. Tacconi L, Signorelli F, Giordan E. Cervical foraminotomy by full-endoscopic posterior cervical approach: a randomized study. Interdiscip Neurosurg. 2021;26:101287. high-definition optics and displays with crisp resolution. Additionally, the hydrostatic pressure afforded by the continual irrigation reduces bleeding from the venous plexus that can be problematic during an open or tubu lar PCF. Furthermore, the off-axis viewing angle of the endoscope allows the surgeon to see around corners and even turn and look laterally back out the foramen (Figure 2). The lateral aspects of the pedicles can be directly visualized as they slope away, confirming that de compression is complete. Despite the benefits of endoscopic PCF, it is not an entry-level endoscop ic procedure, as the can nula must remain safe ly docked on the dorsal osseous structures while instruments are carefully advanced into the canal and foramen. Failing to do so could result in neurologic injury. This challenge is certainly surmountable as surgeons become more experienced and comfortable with endoscopic techniques in the lumbar spine. Once mastered, endoscopic PCF can become a valuable, ultra-minimally invasive tool for the treatment of cervical radiculopathy. l
2. Liu WJ, Hu L, Chou PH, Wang JW, Kan WS. Comparison of anterior cervical discectomy and fusion versus posterior cervical foraminotomy in the treatment of cervical radiculopathy: a systematic review. Orthop Surg. 2016;8(4):425-431.
Figure 2. Intra operative pho tograph looking laterally out the foramen during a left endoscopicC6-7 pos terior view.totionfromisTheforaminotomy.cervicalendoscoperotated180°itsorientainFigure1achievethis
1. Guo L, Wang J, Zhao Z, et al. Microscop ic anterior cervical discectomy and fusion versus posterior percutaneous endoscopic cervical keyhole foramino tomy for single-level unilateral cervical radiculopathy: a systematic review and meta-analysis [published online March 29, 2022]. Clin Spine Surg
4. Bhatia S, Brooks NP. Posterior endo scopic cervical foraminotomy. Neu rosurg Clin N Am. 2020;31(1):9-16.
8. Kim JY, Hong HJ, Lee DC, Kim TH, Hwang JS, Park CK. Comparative analysis of 3 types of minimally invasive pos terior cervical foraminotomy for fo raminal stenosis, uniportal-, biportal endoscopy, and microsurgery: radio logic and midterm clinical outcomes. Neurospine . 2022;19(1):212-223.
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3. Sahai N, Changoor S, Dunn CJ, et al. Minimally invasive posterior cervical foraminotomy as an alternative to anterior cervical discectomy and fusion for unilateral cervical radiculopathy: a systematic review and meta-analy sis. Spine . 2019;44(24):1731-1739.
References
