Vertebral Columns, Winter 2019

Vertebral Columns International Society for the Advancement of Spine Surgery

ISASS19

Winter 2019

April 3-5, 2019 Anaheim, CA

Grand Plaza at Anaheim, Home of ISASS19. Cover: Grand Plaza at Anaheim. Credit: Visit Anaheim

In This Issue EDITORIAL Acquisition of Orthopedic Practices by Private Equity Investors........... 3 REIMBURSEMENTS Strategies for Success with Spine Bundled Payments............................. 5 CONTINUING EDUCATION Challenges in Postgraduate Spine Surgery Training............................... 7 REVIEW Use of Zero Profile Devices for Multilevel ACDF: What Does the Literature Say? ......................................................................................11

Editor in Chief Kern Singh Editorial Board Peter Derman, MD, MBA Brandon Hirsch, MD Sravisht Iyer, MD Safdar Khan, MD Yu-Po Lee, MD Grant Shifflett, MD Sheeraz Qureshi, MD Publisher Jonny Dover

COMPLICATIONS Minimizing Blood Loss in Spine Surgery............................................. 16

Vertebral Columns is published quarterly by the International Society for the Advancement of Spine Surgery. © 2019 ISASS. All rights reserved.

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

This publication is available digitally at http://vertebralcolumns.com.

ISSN 2414-6277.

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Vertebral Columns • Winter 2019

EDITORIAL

Acquisition of Orthopedic Practices by Private Equity Investors Kern Singh, MD

Orthopedic surgery is one of the fastest growing healthcare segments. Primarily driven by the aging population, orthopedics generates more than 137 million visits to physicians’ offices, hospital outpatient clinics, and emergency departments annually. This rapidly growing field has become a spotlight of attention for investors. According to experts, a surge of investments from venture capitalists and private equity firms is expected to occur in orthopedic practices in the near future. In recent years, specialties such as dermatology, ophthalmology, and urology have transcended into non-hospital based practices and are increasingly being acquired by private equity investors. The rise of ambulatory surgical centers translates to reduced costs associated with surgeries and larger compensations for physicians. Investors have quickly realized the revenue generated by these fields and their future earning potential. The main goal for investors is to continue growth in the practice, increase their stock share value, and then sell for a profit.

Private investors consider Earnings Before Interest, Taxes, Depreciation, and Amortization (EBITDA) before making an initial investment. Investors seek out

“platform practices” which have a well-established management, numerous ancillary services, and a strong community presence.

These private equity firms will partner with physician shareholders and strive to continue the current reimbursement environment. In the process, platform practices will often receive attractive offers from investors seeking partnership. Most of this payment will be cash and the remaining amount is in stock of the new entity. The investment is then dispersed to all shareholders in the practice and physicians then take a reduced salary to enable better cash flow. After a few years of growth, including expansion by acquiring smaller practice groups, newer infrastructure, and higher productivity, investors strive to increase the EBITDA with hopes that they can sell the practice at a premium, resulting in a large return of investment.

With the advancements of surgical techniques and technology, subspecialties such as spine surgery are experiencing a movement from the inpatient to outpatient setting, allowing for quicker, safer, and more efficient procedures. Reimbursements remain the same for these procedures when performed at ambulatory centers, but the cost to perform the surgery decreases, resulting in larger compensation for the surgeon and shareholders. This transition is viewed favorably in the eyes of private equity investors

who seek further growth and profit margins. In relation, private equity investors are mainly involved with the financial aspects of the practice and are historically hands-off when it comes to practice management.

Private equity can also provide the necessary capital for practices to hold ownership stake in the trending outpatient surgery centers, which may require expansion of infrastructure, additional personnel, and newer technology. Thus, practices can increase infrastructure and embrace opportunity for growth, while physicians maintain the ability to run their practice the way they prefer.

Physicians are becoming more open to consolidating practices in order to resist economic pressures from administrators and gain leverage with insurance companies. Over the last few decades, the number of physicians practicing as a sole entity has dropped tremendously.

This number continues to decrease as private equity firms advance in acquiring practices. Deals with private equity firms are more attractive to platform practices that have struggled with inefficient business management and may benefit significantly from business-oriented investor acquisitions. The consolidation of other practices and onboarding of new physicians may allow for purchase of newer technology, which can result in higher quality care, greater efficiency, and more revenue. As these platform Vertebral Columns • Winter 2019

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practices grow in size after acquisition, historically less busy subspecialties will begin to see an increase in volume as referrals within the practice grows. Additionally, physicians who worked as a sole entity in the past but have now been recruited to these platform practices may be able to practice with newer technology that was previously not available.

With the trend in investors acquiring private practices, there will be a continued increase in large orthopedic groups. Â Within orthopedics, an increase in infrastructure will be likely with the rise of ancillary services, such as surgery centers, physical therapy centers, and satellite clinics. Physicians who have significant partnership and stock shares may benefit tremendously with this change in infrastructure, while maintaining autonomy on how their practice is run during the process of acquisition.

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REIMBURSEMENT

Strategies for Success with Spine Bundled Payments Peter Derman, MD, MBA, & Sara Brice, BA Bundled payment is a reimbursement model in which all expenses related to an episode of care are reimbursed at a pre-specified rate.

This system is meant to promote efficiency in healthcare delivery by aligning various providers and healthcare facilities toward a common goal of providing high-quality care while simultaneously streamlining costs. If the actual expenses are less than the set price of the bundle, providers and facilities keep the difference. Conversely, they are responsible for excess costs if expenditures exceed the bundle price.

Early experiments with this payment model began in the 1980s,1,2 but the system reached more widespread adoption with the Center for Medicare & Medicaid Services’ (CMS) implementation of the Bundled Payment for Care Improvement (BPCI) initiative3 in 2013, followed by the Comprehensive Care for Joint Replacement model4 in 2015. Orthopedic and cardiac practices were early participants, but spine bundles have not gained significant traction until recently.

With the start of Bundled Payments for Care Improvement – Advanced (BPCI-A)5 on October 1, 2018, spine practices are increasingly getting involved. There are four spine-related inpatient bundles (non-cervical spinal fusion, com-

bined anterior and posterior fusion, back and neck without fusion, cervical fusion) and one outpatient spine bundle (back and neck except fusion). The deadline for the first round of applications has passed, but CMS will provide a second application opportunity in January 2020. This voluntary program is currently slated to run through December 31, 2023. With the help of a third-party convener, physician group practices can “opt in” to any or all bundles and may re-evaluate their participation at predetermined times.

There are seven quality measures in this model, but only a select few pertain to spine: All-Cause Hospital Readmission Measure, Advanced Care Plan, and CMS Patient Safety Indicators. Payments to participants (or money owed to CMS) will be adjusted based on performance on these metrics.

For physician group practices (PGP) to be successful in the BPCI-A program, physicians must take a more active role in managing each patient’s 90-day episode of care. This requires involvement not only in the acute care setting but in every subsequent interaction the patient has with the healthcare system. Recent studies suggest that discharge to rehabilitation facilities is associated with increased complication rates, unplanned hospital readmissions, and cost of care.6–8 While each patient should be evaluated individually, PGPs

might consider utilizing lower cost services such as home health care to facilitate discharge home after surgery.

The groundwork is laid pre-operatively – physicians should discuss anticipated hospital length of stay and discharge disposition with surgical patients well before the day of surgery. This should be communicated to office staff, physician extenders and the acute care team so that consistent, coordinated messaging can be provided on these topics. These conversations set appropriate patient expectations from the start.

Careful selection of the surgical setting as well as implant and graft options can significantly impact overall cost. Post-operatively, it is important to engage with the acute care hospital or surgical center to ensure that the pre-operative plan of care is followed and that potential deviations from it are communicated to the PGP so that they may be addressed.

The physician group should identify and develop a preferred list of post-acute providers who align their goals with those of the PGP. Online reviews, average length of stay, and rate of transfer to higher acuity settings are important factors to consider. It is often helpful to have a member of the PGP visit rehab centers to see them first hand and develop close working relationships.

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During the 90-day episode of care, it is beneficial for the PGP to regularly communicate with patients and post-acute providers to ensure that appropriate care is being delivered. Keeping close tabs on patients allows the PGP to intervene when necessary to avoid unnecessary ER visits and hospital admissions, which are key drivers of post-operative expenditure.7 While CMS is a key player promoting bundled payments, this model has spread to other insurers and would be expected to become increasingly popular if successful.

Providers, patients and the healthcare system stand to benefit if the incentives provided by bundled payments motivate physicians, facilities, and other providers to align to develop ways to provide quality care at lower cost.

References 1. Edmonds C, Hallman GL. CardioVascular Care Providers. A pioneer in bundled services, shared risk, and single payment. Tex Heart Inst J. 1995;22(1):72-76.

2. Miller HD. From volume to value: better ways to pay for health care. Health Aff Proj Hope. 2009;28(5):1418-1428. doi:10.1377/ hlthaff.28.5.1418 3. Bundled Payments for Care Improvement (BPCI) Initiative: General Information | Center for Medicare & Medicaid Innovation. https:// innovation.cms.gov/initiatives/bundled-payments/. Accessed November 28, 2018.

4. Comprehensive Care for Joint Replacement Model | Center for Medicare & Medicaid Innovation. https://innovation.cms.gov/initiatives/CJR. Accessed November 28, 2018.

5. BPCI Advanced | Center for Medicare & Medicaid Innovation. https://innovation. cms.gov/initiatives/bpci-advanced. Accessed November 28, 2018.

6. Passias PG, Poorman GW, Bortz CA, et al. Predictors of adverse discharge disposition in adult spinal deformity and associated costs. Spine J Off J North Am Spine Soc. 2018;18(10):1845-1852. doi:10.1016/j. spinee.2018.03.022 7. Stephens BF, Khan I, Chotai S, Sivaganesan

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A, Devin CJ. Drivers of Cost in Adult Thoracolumbar Spine Deformity Surgery. World Neurosurg. 2018;118:e206-e211. doi:10.1016/j. wneu.2018.06.155 8. Khormaee S, Samuel AM, Schairer WW, et al. Discharge to Inpatient Facilities After Lumbar Fusion Surgery is Associated with Increased Postoperative Venous Thromboembolism and Readmissions. Spine J Off J North Am Spine Soc. June 2018. doi:10.1016/j. spinee.2018.05.044

CONTINUING EDUCATION

Challenges in Postgraduate Spine Surgery Training Brandon P. Hirsch, MD Today, the practice of spine surgery is more varied and complex than ever before. An explosion of new techniques and technologies in the field has substantially altered the learning curve associated with spine surgery training. Unfortunately, the vast majority of training programs that produce spine surgeons today are very similar in structure and case volume to what they were several decades ago. As a result, a proportion of graduating residents receive suboptimal exposure to the field in comparison to other subspecialties. The increased risk and technical difficulty inherent to spine surgery make this particularly problematic.

Neurosurgical vs. Orthopaedic spine training The path to becoming a spine surgeon is vastly different for neurological and orthopaedic surgical trainees. Neurosurgery residency typically involves seven years of training with most neurosurgeons going on to practice spine surgery without additional fellowship training. Orthopaedic spine surgeons complete a five-year residency program followed by a year of dedicated spine fellowship training. Because a greater proportion of academic neurosurgical practice involves spine procedures than in academic orthopaedic surgery, rotations that involve spine surgery encompass a significantly

greater percentage of time during neurological compared to orthopaedic surgical residency (26 vs. 7 months).1 As one might expect, trainees’ spine procedure volume in each specialty mirrors the amount of time spent on rotations where spine surgery is performed. Daniels et al. completed the most comprehensive study of trainee’s case exposure in the literature, reviewing data from all ACGME-accredited programs in both specialties over four years.2 Neurosurgical residents performed more than twice as many spine surgery cases each year when compared to their orthopaedic colleagues (375 cases vs. 160 cases, p=0.002). Differences in exposure to instrumented cases were less, but neurosurgeons still performed significantly more of these procedures (142 vs. 101 cases, p=0.002). It was only in spinal deformity where orthopaedic surgical residents gained more exposure than neurosurgical residents (9.5 vs. 2.0 deformity arthrodesis cases, p<0.0001).

Even more dramatic was the disparity amongst programs in the same specialty. Within neurosurgery, the programs in the top 10% of spine volume performed 4 times as many spine cases as did the programs in the bottom 10% (665 vs. 166 procedures). Within orthopaedic surgery, the programs in the top 10% of spine volume performed 5.5 times as many spine cases as did the programs in the bottom 10% (316

vs. 57 procedures). The difference in number of instrumented cases between high and low volume programs in each specialty was even larger.

The discrepancy in spine case volume between neurosurgery and orthopaedic surgery trainees is reflected in residents’ own self-assessment of their competency to perform spine procedures. In a 2006 study, Dvorak et al. determined that neurosurgery residents on average described their competence in performing a comprehensive list of 25 spine procedures as “somewhat competent” whereas orthopaedic trainees tended to describe themselves as “a little competent.”1 In a subset of 9 core procedures, neurosurgery residents felt they were on average “very competent” whereas orthopaedic surgery residents described themselves as “somewhat competent.” Neurosurgery residents also perceived less need for additional training in all listed procedures as well as the 9 core procedures. This study has limitations inherent to its design, but contains the only published data on trainee’s perceived aptitude for performing spine surgery following residency. The analyses performed to date in the literature also evaluate the experience of orthopaedic surgery residents prior to completing a spine fellowship, when they have not truly finished spine training. While it would be more apropos to compare the case exposure and perceived preparedVertebral Columns • Winter 2019

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ness of orthopaedic spine surgeons graduating fellowship to neurosurgeons graduating residency, no such studies have been performed to date.

Experience of other surgical specialties The problem of variability in case exposure and concerns about competence of graduating residents is not unique to spine surgery.3-5 As rapid advancements in technique are moving away from traditional open abdominal/thoracic approaches, our colleagues in general surgery have grappled with ensuring both adequate breadth of cases and sufficient volume of each case type.

A 2009 study evaluated the case logs of graduating general surgery residents in the US to determine the level of exposure to 121 case types deemed essential by program directors.6 Essential case types were defined as procedures that a general surgery resident should be competent to perform at graduation. The authors determined that 83 of these 121 case types were performed an average of less than 5 times during training. Forty-seven of the 121 essential cases were performed, on average, less than twice during residency. Furthermore, substantial variation was established amongst individual residentsâ&#x20AC;&#x2122; case exposure.

Quillin et al analyzed the case logs of a residents in a single general surgery program between 1992 and 2015, before and after the 2003 implementation of work hour restrictions.5 The authors concluded that although overall case volume did not change after work hour restrictions took effect, there was a significant increase in variability of residentsâ&#x20AC;&#x2122; operative volume amongst peers in the same graduating class. This cause for this dis8

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parity in experience was thought to be multifactorial but likely related to the natural tendency of talented residents to seek out more operative volume whereas less skilled residents might not do so.

Laboratory-based surgical simulation training allows for a repetitive, risk-free, learner-focused experience while alleviating concerns for patient safety, liability, and operating room efficiency inherent to on-the-job training.

Opportunities for improving spine surgery training Other surgical subspecialties have adapted to the perceived inadequacy in training by moving from traditional general surgery residency programs into separate integrated programs with early subspecialization (plastic surgery, vascular surgery, etc.). Many have suggested that spine surgery follow a similar path, with or without shorter general training in orthopaedics or neurosurgery.7 While this would be an ideal improvement upon the current system, several obstacles have prevented this from happening. Such an effort would require significant restructuring of both academic departments currently responsible for training spine surgeons. These departments tend to be part of larger organizations that by their nature are resistant to change in the status quo. Most senior leaders responsible for training programs today became spine surgeons via the current system and may feel that because they did so

successfully that change is unnecessary. A new training pathway would also require additional financial resources, diverting significant revenue generated by spine surgery away from neurosurgery or orthopaedic departments where it is needed. Lastly, as a separate subspecialty, spine surgery would require recognition from the ACGME, as well as creating a new medical board to supervise certification. Achieving both would involve a lengthy, resource-intensive administrative effort.

These obstacles in and of themselves are not a reason to forego development of a more focused, effective training pathway for spine surgeons, but there may be other opportunities for improvement that are more easily achievable in the short term. One promising alternative is the development of simulation platforms for spine surgery. Laboratory-based surgical simulation training allows for a repetitive, risk-free, learner-focused experience while alleviating concerns for patient safety, liability, and operating room efficiency inherent to on-the-job training. A variety of options exist for surgical simulation training ranging from simple use of hardware store materials to three-dimensional virtual reality platforms with haptic feedback. The efficacy and cost effectiveness of simulation has been studied in many procedurally-based fields, including orthopaedic surgery.8-13 While some questions exist about long term durability of skills acquired via simulation, there are clear benefits to laboratory based technical training for residents.9,14,15 Orthopaedic residency programs have embraced simulation such that structured surgical motor skills training was

made a requirement for accreditation by the ACGME in 2013.

starting point accuracy, both groups allowed to train with 3D navigation feedback improved their angular trajectory accuracy.

while the control subjects did not.

Treatment group participants also significantly improved their ability to detect pedicle breaches whereas “Lower-tech” opcontrol subjects were less accurate While high-fidelity options for in doing so. In both papers, authors tions for spine surgery simulation are effective in spine concluded that Sawbones skills simulation exist and surgery training they require signifi- simulation in spine training could have also been shown cant financial resources, a barrier be a powerful tool to augment the to improve the skills of to implementation in an era of cost surgical education of residents and constraints on residency training. fellows. trainees. Boody et al “Lower-tech” options for spine used a Sawbones model surgery simulation exist and have Conclusion of degenerative lumbar also been shown to improve the skills of trainees. Boody et al used As in other surgical subspecialstenosis augmented with a Sawbones model of degenerative ties, a combination of pressure on a water balloon simulumbar stenosis augmented with a clinical productivity, heightened lating the thecal sac to water balloon simulating the thecal patient safety/medicolegal contrain 20 residents on sac to train 20 residents on lumbar cerns, and budgetary constraints 20 laminectomy. Treatment group limit the intraoperative experience lumbar laminectomy. subjects trained for 40 minutes of spine surgery trainees. As a on the model guided by a senior result, spine surgery education A variety of simulation platforms resident while controls spent 40 today varies significantly in quality for spine surgery training have been minutes reading a spine surgery and causes many graduating trainstudied, with promising results.16,17 textbook chapter on lumbar deees to shift their experience with Luciano et al analyzed the impact compression. The authors deterthe technical learning curve to their of training with a three dimension- mined that when compared with early practice. In order to produce al, haptic feedback virtual reality controls, treatment group subjects the next generation of safe, compesystem on thoracic pedicle screw improved significantly more, both tent spine surgeons, educators and placement accuracy for 51 neuon objective skills scoring by a pupils alike must embrace changes rosurgery trainees.18 The authors blinded evaluator and on self-asto the traditional model of training. discovered a 15% improvement in sessed rating of knowledge and Our colleagues in other surgical accuracy of starting point and screw skill. The same investigators also fields have done so successfully by tip position with a 50% reduction in conducted a study on simulation of adopting integrated subspecialized standard deviation amongst partici- lumbar pedicle screw placement in residency programs and incorporat21 pants after training with the system. a Sawbones model. In this analying simulation as a cornerstone of A 2015 study supported by the sis, treatment subjects underwent a postgraduate education. A similar Cervical Spine Research Society 20-minute technical demonstration evolution in spine surgery training evaluated the effect of training with using the model while controls is inevitable and would be best lead a conventional 3D navigation on utilized a standard text book during from within rather than mandated orthopaedic surgery residents and the same time period. Subjects by an external regulatory body. fellows’ ability to place lateral mass were then asked to place pedicle screws.19 This study randomized screws from L1 to L5 on the model. References three groups of trainees to either no Additionally, subjects were asked 1. Dvorak MF, Collins JB, Murnaghan L, et training, navigation training with to use a ball-tip probe to identify al. Confidence in spine training among senior neurosurgical and orthopedic residents. Spine a cadaver, or navigation training intentional pedicle wall breaches (Phila Pa 1976) 2006;31:831-7. with a Sawbones model. Starting created by the authors on separate point and angular screw trajectomodel. Trainees who underwent 2. Daniels AH, Ames CP, Smith JS, et al. Variability in spine surgery procedures performed ries were measured and compared skills training using the model during orthopaedic and neurological surgery amongst groups. While no differsignificantly decreased their rate of residency training: an analysis of ACGME case ence between groups was seen with breach on post-intervention testing log data. J Bone Joint Surg Am 2014;96:e196.

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3. Cairo SB, Craig W, Gutheil C, et al. Quantitative Analysis of Surgical Residency Reform: Using Case-Logs to Evaluate Resident Experience. J Surg Educ 2018.

4. Fingeret AL, Stolar CJ, Cowles RA. Trends in operative experience of pediatric surgical residents in the United States and Canada. J Pediatr Surg 2013;48:88-94.

5. Quillin RC, 3rd, Cortez AR, Pritts TA, et al.

Operative Variability Among Residents Has Increased Since Implementation of the 80-Hour Workweek. J Am Coll Surg 2016;222:1201-10.

6. Bell RH, Jr., Biester TW, Tabuenca A, et al.

Operative experience of residents in US general surgery programs: a gap between expectation and experience. Ann Surg 2009;249:719-24.

7. Daniels AH, Ames CP, Garfin SR, et al. Spine surgery training: is it time to consider categorical spine surgery residency? Spine J 2015;15:1513-8.

8. Stirling ER, Lewis TL, Ferran NA. Surgical skills simulation in trauma and orthopaedic training. J Orthop Surg Res 2014;9:126.

9. Atesok K, Mabrey JD, Jazrawi LM, et al.

Surgical simulation in orthopaedic skills training.

J Am Acad Orthop Surg 2012;20:410-22.

10. Pedowitz RA, Marsh JL. Motor skills training

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in orthopaedic surgery: a paradigm shift toward a simulation-based educational curriculum. J Am Acad Orthop Surg 2012;20:407-9.

11. Atesok K, Satava RM, Van Heest A, et al. Retention of Skills After Simulation-based Training in Orthopaedic Surgery. J Am Acad Orthop Surg 2016;24:505-14.

12. Franzeck FM, Rosenthal R, Muller MK, et al. Prospective randomized controlled trial of simulator-based versus traditional in-surgery laparoscopic camera navigation training. Surg Endosc 2012;26:235-41.

13. Zendejas B, Cook DA, Bingener J, et al.

Simulation-based mastery learning improves patient outcomes in laparoscopic inguinal hernia repair: a randomized controlled trial. Ann Surg 2011;254:502-9; discussion 9-11.

14. Coughlin RP, Pauyo T, Sutton JC, 3rd, et al.

A Validated Orthopaedic Surgical Simulation Model for Training and Evaluation of Basic Arthroscopic Skills. J Bone Joint Surg Am 2015;97:1465-71.

15. Lopez G, Wright R, Martin D, et al. A cost-effective junior resident training and assessment simulator for orthopaedic surgical skills via fundamentals of orthopaedic surgery: AAOS exhibit selection. J Bone Joint Surg Am 2015;97:659-66.

16. Ryu WHA, Mostafa AE, Dharampal N, et al. Design-Based Comparison of Spine Surgery Simulators: Optimizing Educational Features of Surgical Simulators. World Neurosurg 2017;106:870-7 e1.

17. Pfandler M, Lazarovici M, Stefan P, et al. Virtual reality-based simulators for spine surgery: a systematic review. Spine J 2017;17:1352-63.

18. Luciano CJ, Banerjee PP, Bellotte B, et al.

Learning retention of thoracic pedicle screw placement using a high-resolution augmented reality simulator with haptic feedback. Neurosurgery 2011;69:ons14-9; discussion ons9.

19. Gottschalk MB, Yoon ST, Park DK, et al. Surgical training using three-dimensional simulation in placement of cervical lateral mass screws: a blinded randomized control trial. Spine J 2015;15:168-75.

20. Boody BS, Rosenthal BD, Jenkins TJ, et al. The Effectiveness of Bioskills Training for Simulated Open Lumbar Laminectomy. Global Spine J 2017;7:794-800.

21. Boody BS, Hashmi SZ, Rosenthal BD, et al.

The Effectiveness of Bioskills Training for Simulated Lumbar Pedicle Screw Placement. Global Spine J 2018;8:557-62.

REVIEW

Use of Zero Profile Devices for Multilevel ACDF: What Does the Literature Say? Philip J York MD, Yoshihiro Katsuura MD, Sheeraz A Qureshi MD MBA

Introduction Since the first documented description of the anterior cervical discectomy and fusion (ACDF) procedure in 1958 by both Smith and Robinson1 and Cloward,2 there has been a variety of implants and techniques described to obtain targeted alignment and to promote an interbody fusion.

Standalone grafts were initially used independently followed by the development of anterior cervical plates to prevent graft displacement and to provide a means of controlling sagittal alignment. The use of anterior plates, however, has been established to enhance early fusion with decreased overall risk of pseudarthrosis and graft subsidence,3,4 both of which are particularly relevant in the case of multi-level fusions. While anterior cervical plates are now widely implanted based on long-standing success, there has been some concern regarding the effects that they can have on adjacent level ossification (ALO),5 dysphagia,6 and rare, but potentially catastrophic complications, such as esophageal perforation or visceral injury due to hardware failure or screw backout.7 Even with historically excellent outcomes with ACDF performed with cage and plate (CP) techniques in terms of fusion rates, patient-reported outcomes, and low complication profile,8 zero profile (ZP)

devices for interbody graft fixation in ACDF procedures have become increasingly popular in recent years.

The purpose behind the advent of these devices was to improve the ease of insertion and further decrease complications seen with prominent anterior cervical plates, all while maintaining the established success regarding patient outcomes.

Early studies focused their use in single-level procedures, with many reporting decreased rates of ALO9 and dysphagia.10,11 Additionally, these devices have been promoted as an effective and safe means of addressing adjacent segment degeneration (ASD), especially in cases where it may not be desirable to remove a previous anterior plate.12 With encouraging early reports of their efficacy in single-level or even multiple, noncontiguous-level surgeries, there has been a desire by many to push the envelope to implement these devices in multi-level disease. The potential promise of decreasing dysphagia rates, avoiding long anterior plates that increase the complexity of revisions, and decreasing surgical time and blood loss in these cases is appealing. The obvious concern with any multilevel procedure, however, is the increasing rates of pseudarthrosis.13 Therefore, we aim to summarize key topics discussed in the current literature regarding the use of ZP devices in the setting of multilevel ACDF to provide the surgeon with current evidence of the pros and cons and to provide suggestions regarding future investigations.

Dysphagia There is growing evidence that ZP decreases the rates of dysphagia compared to CP. This is of particular interest in regards to multilevel cervical surgery which, in and of itself, has been directly linked to an increased risk for dysphagia.15,16 There have been recent reports that the incidence is as high as 70%,17 with resolution in most cases within 2-3 months.6 However, patients who undergo surgery involving more than 2-levels are at significant risk of prolonged dysphagia lasting over two years.18 A 2017 investigation of the safety and feasibility of 3 and 4-level ZP ACDF utilizing the Zero-P (DePuy Synthes, West Chester, PA) reported a 20.8% incidence of dysphagia, mostly mild with only 2 patients having midterm dysphagia lasting 6 months. They reported no long term or moderate-severe dysphagia.19 Since 2017, there have been a number of comparative studies that have reported lower rates of dysphagia in multilevel surgeries utilizing ZP devices compared to CP at all time points postoperatively.9,20–24 However, there have been several studies which failed to demonstrate a difference in dysphagia rates.25,26 A well-designed 2016 comparison

by Chen et al26 of 54 patients who underwent 3-level ACDF by the same surgeon using either a PEEKZP device (ROI-C® or ROI-MC+®, LDR, France; 28 patients) vs CP (26 patients) reported no differences in Vertebral Columns • Winter 2019

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dysphagia rates.

Based on the current available data, it is clear that the rates of dysphagia in multilevel ACDF with ZP devices are at least equivalent to if not significantly better than those reported with CP. There are several reasons for this phenomenon. First, it has been suggested that, even with lower profile anterior plates, the presence of the plate might cause mechanical irritation,11,27 although this theory is debated in the literature.28 Secondly, it has been reported that incision length has demonstrated to be an independent risk factor associated with dysphagia29 which might be related to a greater exposure required for CP vs ZP fixation. Finally, some have suggested that the shorter operative time that has been reported with the use of ZP devices might indirectly be a marker of decreased esophageal retraction which could affect dysphagia rates, especially in multilevel procedures.30 Clinical Outcomes and Complications Early reports showed significant improvement in a number of clinical outcome parameters including JOA, NDI, VAS neck and arm, Nurick score and SF-36 mental and physical components following multilevel ZP

Figure 1. Example radiographs of patients treated with multilevel zero-profile ACDF. (Top) 3 consecutive level cervical degeneration and (Bottom) 2-level degeneration distal to a prior standard ACDF with a cage and plate.

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ACDF.19 Numerous comparative studies demonstrated these improvements are equivalent to those seen with standalone cages without fixation and/or CP constructs in multilevel ACDF.21â&#x20AC;&#x201C;23,31 Shorter operative time21,23,25,26 and decreased complication rates26 have been reported with the use of ZP devices for multilevel surgeries in a number of recent studies. To our knowledge, there have been no comparative studies that have established inferior clinical outcomes or higher rates of complications with ZP apart from those that relate to pseudarthrosis or subsidence (discussed below).

Adjacent Level Ossification The risk ALO in ACDF with an anterior plate is technique dependent and related to the proximity of the plate to the adjacent cranial or caudal endplate.5,32 ZP devices, do not encroach on the adjacent disc space and are theorized to decrease rates of ALO. A 2018 study of the efficacy of ZP devices in the case of skip level cervical degeneration with non-contiguous ACDF revealed that the ZP device group had significantly lower ALO with no cases identified compared to 19% of cases in the non-contiguous CP group.21 In two studies comparing ZP with ACDF, ZP had a lower rate of ALO (1-2%) compared with CP (18%) at 1 to 3 years postoperatively.9,26 These results, however, were not broken down by number of levels fused.

Ultimately, ZP devices are advantageous as they avoid close proximity to the adjacent, unfused segments which can decrease ALO. Alignment and Subsidence ZP devices have been capable of generating significant cervical lordosis postoperatively.19 Howev-

er, similar to other techniques, ZP devices undergo some degree of subsidence over time with a slight loss of final lordosis compared to the early postoperative lordosis.22 The comparative studies have revealed mixed results as to whether ZP or CP is superior regarding lordosis creation and maintenance in the face of graft subsidence. Yun et al in 201825 reported significantly greater increase in segmental cervical lordosis and intervertebral height both at 3 months and at final follow up in the ZP compared to CP group with no differences in subsidence rates. Other studies have reported no significant differences either in postoperative alignment or in rates of subsidence.20,22,23 While Chen et al in 2016 reported that ZP patients exhibited a greater loss in lordosis from immediately postop to 2-year follow up radiographs with greater subsidence seen at the 3-month postoperative mark, a difference between ZP and CP groups which was maintained through final follow up.26 Currently, the data is inconclusive in regards to whether or not there is a difference in the ability to introduce changes in sagittal alignment between ZP and CP devices. ZP devices appear to be capable of introducing and maintaining reasonable alignment without an unacceptable rate of graft subsidence compared to other options.

Fusion Rates There are a number of challenges in evaluating the rates of fusion following ACDF presented in the current literature. First, various studies report fusion rates with inconsistent length of follow up which has been shown to directly affect reported rates.33 At 1 year postoperatively, it is expected that approximately 30% of patients will have evidence of

pseudarthrosis and this incidence is correlated with the number of levels fused.34 However, a majority of patients with pseudarthrosis at 1 year will go on to fuse by 2 years.

Previous reports have also suggested that only 30% of pseudarthroses following ACDF are asymptomatic.35 However, this leaves a majority of cases in which pseudarthrosis results in compromised outcomes.3,36 While some have suggested that patients with evidence of painful pseudarthrosis at 1-year might be candidates for revision fusion, the question remains as to when the appropriate time to intervene as well as if and how delayed fusion alters patient outcomes.

The current literature examining fusion rates of ZP devices in multilevel ACDF highlights these challenges.

A recent study evaluating patients with minimum of 3-year follow up reported no differences in fusion rates between ZP and CP in 2-3 level fusions with no evidence of pseudarthrosis in either group.31 Another study of two-level, noncontiguous ACDF with ZP versus CP also reported no evidence of pseudarthrosis in either group at minimum 1-year follow up. This differs from another recent report by Albanese et al19 of multilevel (contiguous 3 and 4 level) ZP ACDF in 24 patients with mean follow up of 39 months where just less than 50% of patient achieved a solid fusion at final follow up based on CT scan, although this study had no comparison group and included patients with a minimum follow up of 12 months. In a more recent investigation comparing 1-4 level fusions using the ZP device, Fidji cervical cage (Abbott Spine, Bordeaux, France), and CP constructs in 138 patients reported that there was no significant difference in fusion rates (91.2% vs 92.9%) at Vertebral Columns â&#x20AC;˘ Winter 2019

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final follow up ranging from 24-48 months.22 While it has been suggested that CP devices lead to earlier and higher fusion rates over time, the available literature does not fully support this.22 Recommendations for Future Investigation While there have been numerous studies investigating outcomes regarding ZP and CP ACDF, there is still much to learn and additional studies to fully elucidate differences in performance or indications between these implants are required.

There is a paucity of well-designed, randomized trials looking at patients of comparable degrees of pathology to elucidate these differences in a more meaningful way. Additionally, in terms of topics such as dysphagia and ALO, both of which are known to be technique-dependent complications, an effort to control for this could be warranted (eg. looking at cases of ALO in CP versus ZP when the plate to end-plate distance is measured to be greater than 5mm). Prospective studies should standardize the surgical technique, have clearly defined timelines for radiographic analysis of and criteria for pseudarthrosis, and match these outcomes based on location and number of surgical levels while controlling for other potential causes of pseudarthrosis or subsidence.

Conclusion ZP devices have demonstrated to be safe and effective for the treatment of multilevel cervical spondylosis.

Clinical outcomes are comparable to those seen with CP use. The current literature is most consistent in terms of ZP devices having an advantage in regards to postoperative dysphagia, operative time, and 14

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decreased rates of ALO. While there is concern over the ability to control sagittal alignment, achieve sufficient fusion and avoid untoward graft subsidence with the use of ZP for multilevel disease, the current literature does not support superiority of ZP or CP in this regard.

Additional studies with appropriate methodology and increased patient numbers are warranted.

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2. Cloward RB. The Anterior Approach for Removal of Ruptured Cervical Disks. J Neurosurg Spine. 1958;15(6):601-617. doi:10.3171/ spi.2007.6.5.496 3. Kaiser MG, Haid RW, Subach BR, Barnes B, Rodts GE. Anterior cervical plating enhances arthrodesis after discectomy and fusion with cortical allograft. Neurosurgery. 2002;50(2):22936; discussion 236-8. http://www.ncbi.nlm.nih. gov/pubmed/11844257. Accessed November 13, 2018.

4. Oliver JD, Goncalves S, Kerezoudis P, et al. Comparison of Outcomes for Anterior Cervical Discectomy and Fusion With and Without Anterior Plate Fixation. Spine (Phila Pa 1976). 2018;43(7):E413-E422. doi:10.1097/ BRS.0000000000002441 5. Park J-B, Cho Y-S, Riew KD. Development of Adjacent-Level Ossification in Patients with an Anterior Cervical Plate. J Bone Jt Surg.

2005;87(3):558-563. doi:10.2106/JBJS.C.01555 6. Cho SK, Lu Y, Lee D-H. Dysphagia following anterior cervical spinal surgery. Bone Joint J. 2013;95-B(7):868-873. doi:10.1302/0301620X.95B7.31029 7. Fountas KN, Kapsalaki EZ, Machinis T, Robinson JS. Extrusion of a Screw Into the Gastrointestinal Tract After Anterior Cervical Spine Plating. J Spinal Disord Tech. 2006;19(3):199203. doi:10.1097/01.bsd.0000164164.11277.49 8. Mullins J, Pojskić M, Boop FA, Arnautović KI. Retrospective single-surgeon study of 1123 consecutive cases of anterior cervical discectomy and fusion: a comparison of clinical outcome parameters, complication rates, and costs between outpatient and inpatient surgery groups, with a literature review. J Neurosurg Spine. 2018;28(6):630-641. doi:10.3171/2017.10.

SPINE17938 9. Yang H, Chen D, Wang X, Yang L, He H. Zero-profile integrated plate and spacer device reduces rate of adjacent-level ossification development and dysphagia compared to ACDF with plating and cage system. Arch Orthop Trauma Surg. 2015;(415):781-787. doi:10.1007/s00402015-2212-z 10. Liu W, Hu L, Wang J, Liu M, Wang X. Comparison of zero-profile anchored spacer versus plate-cage construct in treatment of cervical spondylosis with regard to clinical outcomes and incidence of major complications: a meta-analysis. Ther Clin Risk Manag. 2015;11:1437. doi:10.2147/TCRM.S92511 11. Scholz M, Schnake KJ, Pingel A, Hoffmann R, Kandziora F. A New Zero-profile Implant for Stand-alone Anterior Cervical Interbody Fusion.

Clin Orthop Relat Res. 2011;469(3):666-673. doi:10.1007/s11999-010-1597-9 12. Wang F, Wang P, Miao D, Du W, Shen Y. Different surgical approaches for the treatment of adjacent segment diseases after anterior cervical fusion. Medicine (Baltimore).

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13. Lu DC, Tumialán LM, Chou D. Multilevel anterior cervical discectomy and fusion with and without rhBMP-2: a comparison of dysphagia rates and outcomes in 150 patients. J Neurosurg Spine. 2013;18(1):43-49. doi:10.3171/2012.10.

SPINE10231 14. Edwards CC, Karpitskaya Y, Cha C, et al.

Accurate identification of adverse outcomes after cervical spine surgery. J Bone Joint Surg Am. 2004;86-A(2):251-256. http://www.ncbi.nlm. nih.gov/pubmed/14960668. Accessed November 14, 2018.

15. Wu B, Song F, Zhu S. Reasons of Dysphagia After Operation of Anterior Cervical Decompression and Fusion. Clin Spine Surg. 2017;30(5):E554-E559. doi:10.1097/ BSD.0000000000000180 16. Bazaz R, Lee MJ, Yoo JU. Incidence of dysphagia after anterior cervical spine surgery: a prospective study. Spine (Phila Pa 1976).

2002;27(22):2453-2458. doi:10.1097/01.

BRS.0000031407.52778.4B 17. Rihn JA, Kane J, Albert TJ, Vaccaro AR, Hilibrand AS. What Is the Incidence and Severity of Dysphagia After Anterior Cervical Surgery?

Clin Orthop Relat Res. 2011;469(3):658-665. doi:10.1007/s11999-010-1731-8 18. Lee MJ, Bazaz R, Furey CG, Yoo J. Risk factors for dysphagia after anterior cervical spine surgery: a two-year prospective cohort study. Spine J. 2007;7(2):141-147. doi:10.1016/j. spinee.2006.02.024 19. Albanese V, Certo F, Visocchi M, Barbagallo GM V. Multilevel Anterior Cervical Diskectomy and Fusion with Zero-Profile Devices: Analysis of Safety and Feasibility, with Focus on Sagittal

Alignment and Impact on Clinical Outcome: Single-Institution Experience and Review of Literature. World Neurosurg. 2017;106:724-735. doi:10.1016/j.wneu.2017.06.051 20. Lu Y, Bao W, Wang Z, et al. Comparison of the clinical effects of zero-profile anchored spacer (ROI-C) and conventional cage-plate construct for the treatment of noncontinguous bilevel of cervical degenerative disc disease (CDDD). A minimum 2-year follow-up. Medicine (Baltimore). 2018;5(May 2017):1-7.

21. Zhang Z, Li Y, Jiang W. A comparison of zero-profile anchored spacer ( ROI-C ) and plate fixation in 2-level noncontiguous anterior cervical discectomy and fusion- a retrospective study.

BMC Musculoskelet Disord. 2018;119(19):1-7.

22. Li Z, Zhao Y, Tang J, Ren D. A comparison of a new zero-profile , stand-alone Fidji cervical cage and anterior cervical plate for single and multilevel ACDF : a minimum 2-year follow-up study. Eur Spine J. 2017:1129-1139. doi:10.1007/ s00586-016-4739-2 23. He S, Feng H, Lan Z, et al. A Randomized Trial Comparing Clinical Outcomes Between Zero-Profile and Traditional Multilevel Anterior Cervical Discectomy and Fusion Surgery for Cervical Myelopathy. Spine (Phila Pa 1976). 2018;43(5):259-266. doi:10.1097/ BRS.0000000000002323 24. Overley SC, Merrill RK, Leven DM, Meaike JJ, Kumar A, Qureshi SA. A Matched Cohort Analysis Comparing Stand-Alone Cages and Anterior Cervical Plates Used for Anterior Cervical Discectomy and Fusion. Glob Spine J. 2017;7(5):394-399. doi:10.1177/2192568217699211 25. Yun D, Lee S, Park S, et al. Use of a Zero-Profile Device for Contiguous 2-Level Anterior Cervical Diskectomy and Fusion: Comparison with Cage with Plate Construct. World Neurosurg. 2018;97( Jan):189-198. doi:10.1016/j. wneu.2016.09.065 26. Chen Y, Lü G, Wang B, Li L, Kuang L. A comparison of anterior cervical discectomy and fusion (ACDF) using self-locking standalone polyetheretherketone (PEEK) cage with ACDF using cage and plate in the treatment of three-level cervical degenerative spondylopathy:

a retrospective study with 2-year follow-up. Eur Spine J. 2016;25(7):2255-2262. doi:10.1007/ s00586-016-4391-x 27. Lee MJ, Bazaz R, Furey CG, Yoo J. Influence of anterior cervical plate design on Dysphagia: a 2-year prospective longitudinal follow-up study. J Spinal Disord Tech. 2005;18(5):406-409. http:// www.ncbi.nlm.nih.gov/pubmed/16189451.

Accessed November 14, 2018.

28. Chin KR, Eiszner JR, Adams SB. Role of plate thickness as a cause of dysphagia after anterior cervical fusion. Spine (Phila Pa 1976). 2007;32(23):2585-2590. doi:10.1097/ BRS.0b013e318158dec8 29. Wang T, Wang H, Bai Z, Zhang L, Ding W. Factors predicting dysphagia after anterior cervical surgery. Medicine (Baltimore). 2017;34(August):1-7.

30. Saville P, Vaishnav AS, McAnany S, Gang CH, Qureshi SA. Predictive Factors of Post-operative Dysphagia in Single-level Anterior Cervical Discectomy and Fusion (ACDF). Spine (Phila Pa 1976). 2018;Epub ahead. doi:10.1097/ BRS.0000000000002865 31. Chen Y, Chen H, Wu X, Wang X, Lin W, Yuan W. Comparative analysis of clinical outcomes between zero-profile implant and cages with plate fixation in treating multilevel cervical spondilotic myelopathy : A three-year follow-up.

Clin Neurol Neurosurg. 2018;144(2016):72-76. doi:10.1016/j.clineuro.2016.03.010 32. Park J-H, Hyun S-J, Lee C-H, et al. Efficacy of a Short Plate With an Oblique Screw Trajectory for Anterior Cervical Plating: A Comparative Study With a 2-Year Minimum Follow-Up. Clin spine Surg. 2016;29(1):E43-8. doi:10.1097/ BSD.0000000000000111 33. Shriver MF, Lewis DJ, Kshettry VR, Rosenbaum BP, Benzel EC, Mroz TE. Pseudoarthrosis rates in anterior cervical discectomy and fusion: a meta-analysis. Spine J. 2015;15(9):2016-2027. doi:10.1016/j.spinee.2015.05.010

35. Bohlman HH. Cervical spondylosis and myelopathy. Instr Course Lect. 1995;44:81-97. http://www.ncbi.nlm.nih.gov/pubmed/7797895.

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36. Newman M. The outcome of pseudarthrosis after cervical anterior fusion. Spine (Phila Pa 1976). 1993;18(16):2380-2382. http://www. ncbi.nlm.nih.gov/pubmed/8303436. Accessed November 13, 2018.

37. Riederman BD, Butler BA, Lawton CD, Rosenthal BD, Balderama ES, Bernstein AJ. Recombinant human bone morphogenetic protein-2 versus iliac crest bone graft in anterior cervical discectomy and fusion: Dysphagia and dysphonia rates in the early postoperative period with review of the literature. J Clin Neurosci.

2017;44:180-183. doi:10.1016/j.jocn.2017.06.034 38. Eastlack RK, Garfin SR, Brown CR, Meyer SC. Osteocel Plus Cellular Allograft in Anterior Cervical Discectomy and Fusion. Spine (Phila Pa 1976). 2014;39(22):E1331-E1337. doi:10.1097/ BRS.0000000000000557 39. Zadegan SA, Abedi A, Jazayeri SB, Bonaki HN, Vaccaro AR, Rahimi-Movaghar V. Clinical Application of Ceramics in Anterior Cervical Discectomy and Fusion: A Review and Update. Glob Spine J. 2017;7(4):343-349. doi:10.1177/2192568217699201 40. Arnold PM, Sasso RC, Janssen ME, et al. i-FactorTM Bone Graft vs Autograft in Anterior Cervical Discectomy and Fusion: 2-Year Follow-up of the Randomized Single-Blinded Food and Drug Administration Investigational Device Exemption Study. Neurosurgery.

2018;83(3):377-384. doi:10.1093/neuros/nyx432 41. Wen Z, Lu T, Wang Y, Liang H, Gao Z, He X. Anterior Cervical Corpectomy and Fusion and Anterior Cervical Discectomy and Fusion Using Titanium Mesh Cages for Treatment of Degenerative Cervical Pathologies: A Literature Review. Med Sci Monit. 2018;24:6398-6404. doi:10.12659/MSM.910269

34. Lee D-H, Cho JH, Hwang CJ, et al. What Is the Fate of Pseudarthrosis Detected 1 Year After Anterior Cervical Discectomy and Fusion?

Spine (Phila Pa 1976). 2018;43(1):E23-E28. doi:10.1097/BRS.0000000000002077

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COMPLICATIONS

Minimizing Blood Loss in Spine Surgery Yu-Po Lee, MD Introduction Over the last few decades, the number of spine surgeries worldwide has dramatically increased and this trend is likely to continue with an aging population. A large dilemma in spine surgery is blood loss and the need for transfusions. Increased blood loss leads to higher rates of morbidity and mortality, so strategies aimed at decreasing blood loss are likely to improve surgical and clinical outcomes. This article will review preoperative, intraoperative, and postoperative strategies that have been successful in minimizing blood loss in spine surgery.

Preoperative Strategies One strategy to prevent postoperative anemia is to have normal hemoglobin levels at the time of surgery.

As a standard preoperative protocol, blood tests should be performed for all patients. Anemia has been defined by the World Health Organization as < 13.0 g/dL for males and < 12.0 g/dL for females. In the case of low preoperative hemoglobin, additional lab tests may be warranted including a complete blood count, serum ferritin, transferrin saturation index (TSAT), vitamin B12, folic acid, inflammatory markers (e.g. serum C-reactive protein), and renal function (e.g. serum creatinine). It has been reported that up to 50% of cases of low hemoglobin may be due to iron deficiency anemia. Replacement with oral or even intravenous iron is a simple but effective solu16

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tion. Most people with iron deficiency need 150-200 mg of elemental iron per day. Additionally, causes of anemia aside from iron deficiency should be carefully investigated.

Erythropoietin is an effective method to increase preoperative hemoglobin. Three or four weekly subcutaneous injections (600 IU/kg) is the most frequently used protocol and has demonstrated excellent outcomes. However, a major disadvantage of erythropoietin is the high cost. For this reason, erythropoietin use is suggested when the patient has anemia and meets the criteria for blood transfusion but a compatible blood type is not available or the patient declines a blood transfusion because of religious beliefs (e.g.

Jehovah’s Witness). Adverse events have been reported in 5% of patients that have been treated with erythropoietin including deep venous thrombosis (DVT), pulmonary embolism (PE), fever, hypokalemia, urinary tract infections, nausea, hypoxia, and vomiting.

Cardiovascular disease is common in patients planning to undergo spine surgery. With an aging population, many of these patients have coronary artery disease with stenting or other cardiac conditions that require antiplatelet therapy. When possible, elective surgeries should be avoided within the first year of stent implantation, as there is a potential 5- to 10-fold increase in acute stent thrombosis. After the first year, most of these patients continue with single antiplatelet therapy. The main concern regarding antiplatelet

agents is the perioperative bleeding that can occur during the procedure, which may be increased up to 50% in patients with dual antiplatelet therapy. Additionally, formation of epidural hematomas is a concern with antiplatelet therapy. The two most commonly prescribed antiplatelet drugs are aspirin and clopidogrel.

Aspirin should be discontinued 7-10 days before surgery and resumed within 24 hours following surgery in patients with a low bleeding risk.

Regarding clopidogrel, most guidelines suggest discontinuation of clopidogrel 5 days prior to surgery, and if additional DVT prophylaxis is needed, a low molecular weight heparin (LMWH) should be used.

Intraoperative Strategies Patients deciding to have spine surgery might consider a minimally invasive procedure which uses smaller incisions and requires less muscle dissection to achieve equivalent results to open spine surgery.

The main advantages of minimally invasive spine surgery are less blood loss, fewer complications, and a shorter hospital stay. For these reason, minimally invasive spine surgery is gaining popularity. In addition to the shift of minimally invasive techniques, there are several intraoperative agents that may reduce blood loss.

The use of tranexamic acid (TXA) has become a popular option when blood loss is anticipated. Many studies have proven its efficacy without an increased risk of complications such as DVT, PE, or wound

infection. The typical dosing of TXA includes a 10 mg/kg intravenous (IV) loading dose followed by 1 mg/kg/hour IV maintenance dose, however, there are some variances to this regimen. The maximum plasma concentration of TXA is reached within 5-15 min after IV injection compared to 30 min after intramuscular (IM) injection and 2 hours after oral tablets. Currently, there are studies that are evaluating topical TXA in decreasing postoperative blood loss.

Hemostatic matrices with thrombin have become popular options in addition to fibrin sealants, which have recently increased in use in other surgical fields. A fibrin sealant is comprised mostly of fibrinogen and human thrombin, forming a stable clot upon application. Many studies have proven its efficacy without increasing the risk of DVTs, PEs, hematomas, wound infections or other complications. However, the main disadvantage with fibrin sealants is the high cost compared

to other hemostatic agents. At this time, further studies are necessary to determine if fibrin sealants have a role in spine surgery.

In addition to hemostatic agents, vasoconstrictors such as epinephrine may also be used to decrease blood loss. In large, open approaches, sponges soaked in epinephrine may be used as packing material at the source of the blood loss. This is a fairly effective strategy in cases where blood continuously oozes from the incision site.

Various techniques have been developed to assist in recycling the patientâ&#x20AC;&#x2122;s own whole blood. Intraoperative red blood cell salvage is a medical procedure involving recovering blood lost during surgery and re-infusing it into the patient. At this time, it is uncertain whether or not the use of red blood cell salvaging techniques decrease the rate of transfusions. Nevertheless, this is a viable option in cases where major blood loss is anticipated.

Postoperative Strategies Postoperative precautions may also reduce further blood loss following spine surgery. Although it is commonly believed that a suction drain placed intraoperatively reduces the formation of a hematoma, many studies have yielded controversial results regarding its use. If a drain is placed, the output should be monitored during the first few hours after surgery. If the output is excessive then releasing the suction and allowing the blood to flow out under gravity is advised.

Conclusion In conclusion, controlling blood loss decreases morbidity and mortality in patients undergoing spine surgery. This review discussed various preoperative, intraoperative, and postoperative measures available to decrease blood loss. Implementation of these strategies may aid in decreasing complications and improving patient outcomes.

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