Perioperative Anticoagulation and Anti-Platelet Medications in Spine Surgery

BY DR PHILIP LOUIE

What we have learned over the last few years and how AO Spine is leading this charge

Considered as one of the most preventable causes of hospital morbidity and mortality following spine surgery, venous thromboembolism (VTE) remains an important concern. In literature, the incidence of VTE after spine surgery ranges anywhere between 0.3% and 31%.1–5 This wide range is due to many factors. Research studies have often grouped patients undergoing surgery for elective, trauma, or oncologic problems. Additionally, there appears to be a lack of consistency in the method and timing of diagnosis. This isn’t an indictment on our ability to perform high-quality research on this topic, but rather it highlights the difficulty in understanding the nuances of this important topic.

So, let’s review what we have learned over the past decade and highlight the global work that AO Spine has performed understanding perspectives of anticoagulation management in spine surgery.

What are the rates and risk factors of VTE in Spine Surgery?

  • Overall spine surgery, VTE incidence following surgery range from 0.3–31%. 1–5
  • Cervical spine surgery demonstrate lower rates of VTE (2.4%) compared to the thoracic (3.6%) and lumbar surgery (7.0%). 6
  • Within cervical spine surgery, posterior cervical fusions had highest rates of VTE (13.4 per 1,000 patients; 2.3 times greater than those undergoing an anterior approach).7
  • Within thoracolumbar spine surgeries, anterior thoracolumbar approaches were associated with the highest VTE risk (13.6%). 8
  • Multi-staged procedures are higher risk for VTE compared to single-staged surgeries (19% vs. 7%). 9
  • When comparing instrumented fusion to decompression-only surgeries, multiple studies have suggested that patients who underwent fusions may bear a greater risk of VTE, and even more so when the fusions spans more than 4 levels. 3,7,10
  • Medical comorbidities associated with increased perioperative VTE risks in spine surgery patients: hypertension, diabetes, and malignancy. 11,12

What are these medications?

  • Antiplatelet: Aspirin, Clopidogrel, Cilostazol
  • Warfarin
  • Unfractionated heparin
  • Low molecular weight heparin (LMWH): Enoxaparin, Dalteparin, Nadroparin
  • Factor Xa inhibitors: Rivaroxaban, Apixaban

Several groups have developed algorithms to guide perioperative anti-coagulation/platelet medication use in spine surgery

  • Antithrombotic Therapies Work Group of the North American Spine Society Evidence-Based Guideline Development Committee 13
    • 14 clinically based questions were devised and reviewed, specifically directed towards the prevalence of DVT and PE in spine surgery and recommendations regarding the use of mechanical and pharmacologic prophylaxis in spine surgery
  • American College of Chest Physicians (ACCP) for non-orthopaedic surgeries 14
  • VTE Risk Index for spinal fusions based on independent risk factors identified in the Nationwide Inpatient Sample 2
    • Created based on the results of a logistic regression model and included components related to the surgical approach, primary diagnosis, ethnicity, and medical comorbidities.
  • VTE Prophylaxis Risk/Benefit Score 15
    • The score incorporates factors associated with patient-specific comorbidity, surgical, and bleeding risks. A final score is established that places patients in 1 of 3 groups.

The AO Spine Global Survey

In 2020, I led an effort with the AO Spine to evaluate the understanding and use of anticoagulation and antiplatelet medications in spine surgery.16 Specifically, alongside several expert members of the AO Spine community (Global Spine Journal Editorial Board and the Regional Research Chairs of AO Spine), we designed and implemented a questionnaire in which 316 spine surgeons across 64 countries participated in. Ultimately, our survey highlighted the heterogeneity of spine care and accentuated wide geographical variations. The one area of agreement across various backgrounds was the thromboprophylaxis treatment plan in patients presenting with spinal cord injury. What became widely apparent, was the difficulty in providing consistent perioperative anticoagulation recommendations to patients, as there remains no widely accepted, definitive literature of evidence or guidelines.

What’s next?

Given the heterogeneity of medical comorbidities, spinal pathology, and surgical techniques, there is certainly a need for patient-specific anticoagulation guidelines in the perioperative setting. My hope is that the recent focus by AO Spine on this important topic will serve as a launching pad for future studies that can apply this data to better understand global-, training-, and practice-specific indications for perioperative thromboprophylaxis. Robust future study designs, such as prospective randomized trials, can help develop guidelines and algorithms, and subsequent updated expert group consensus recommendations for anticoagulation/antiplatelet management in spine surgery.

About the author

Philip Louie, MD is a Spine Surgeon at Virginia Mason Franciscan Health, where he is the Medical Director of Research and Academics for the Center of Neurosciences and Spine. He also serves as the Chief Operating Officer and Co-Founder of STREAMD (AI-powered physician chatbots, clinically proven to engage patients and improve outcomes after surgery). He received his bachelor's degree in Business Administration and Developmental Biology as well as his Medical Degree (MD) at the University of Washington. He subsequently completed his Orthopaedic Surgery Residency at Rush University Medical Center with Midwest Orthopaedics and spine surgery fellowship at the Hospital for Special Surgery in New York City. He has authored over 110 peer-reviewed publications as well as numerous abstracts, book chapters, and regularly presents research at both national and international conferences. He is active with AO and serves as the Spine Representative for the ITC Clinical Science Advisory Commission.

References and further reading:

  1. Oda T, Fuji T, Kato Y, Fujita S, Kanemitsu N. Deep venous thrombosis after posterior spinal surgery. Spine (Phila Pa 1976). 2000;25(22). doi:10.1097/00007632-200011150-00019
  2. Goz V, McCarthy I, Weinreb JH, et al. Venous thromboembolic events after spinal fusion: Which patients are at high risk? J Bone Jt Surg - Am Vol. 2014;96(11). doi:10.2106/JBJS.L.01602
  3. Fineberg SJ, Oglesby M, Patel AA, Pelton MA, Singh K. The incidence and mortality of thromboembolic events in lumbar spine surgery. Spine (Phila Pa 1976). 2013;38(13). doi:10.1097/BRS.0b013e318286b7c0
  4. Sansone JM, Del Rio AM, Anderson PA. The prevalence of and specific risk factors for venous thromboembolic disease following elective spine surgery. J Bone Jt Surg - Ser A. 2010;92(2). doi:10.2106/JBJS.H.01815
  5. Akeda K, Matsunaga H, Imanishi T, et al. Prevalence and countermeasures for venous thromboembolic diseases associated with spinal surgery: A follow-up study of an institutional protocol in 209 patients. Spine (Phila Pa 1976). 2014;39(10). doi:10.1097/BRS.0000000000000295
  6. Smith JS, Fu KMG, Polly DW, et al. Complication rates of three common spine procedures and rates of thromboembolism following spine surgery based on 108,419 procedures: A report from the scoliosis research society morbidity and mortality committee. Spine (Phila Pa 1976). 2010;35(24). doi:10.1097/BRS.0b013e3181cbc8e7
  7. Oglesby M, Fineberg SJ, Patel AA, Pelton MA, Singh K. The incidence and mortality of thromboembolic events in cervical spine surgery. Spine (Phila Pa 1976). 2013;38(9). doi:10.1097/BRS.0b013e3182897839
  8. Piasecki DP, Poynton AR, Mintz DN, et al. Thromboembolic disease after combined anterior/posterior reconstruction for adult spinal deformity: A prospective cohort study using magnetic resonance venography. Spine (Phila Pa 1976). 2008;33(6). doi:10.1097/BRS.0b013e318166dfa3
  9. Edwards CC, Lessing NL, Ford L, Edwards CC. Deep Vein Thrombosis After Complex Posterior Spine Surgery: Does Staged Surgery Make a Difference? Spine Deform. 2018;6(2). doi:10.1016/j.jspd.2017.08.012
  10. Yoshioka K, Murakami H, Demura S, Kato S, Tsuchiya H. Prevalence and Risk Factors for Development of Venous Thromboembolism after Degenerative Spinal Surgery. Spine (Phila Pa 1976). 2015;40(5). doi:10.1097/BRS.0000000000000727
  11. Wang T, Yang SD, Huang WZ, Liu FY, Wang H, Ding WY. Factors predicting venous thromboembolism after spine surgery. Med (United States). 2016;95(52). doi:10.1097/MD.0000000000005776
  12. Piper K, Algattas H, DeAndrea-Lazarus IA, et al. Risk factors associated with venous thromboembolism in patients undergoing spine surgery. J Neurosurg Spine. 2017;26(1). doi:10.3171/2016.6.SPINE1656
  13. Bono CM, Watters WC, Heggeness MH, et al. An evidence-based clinical guideline for the use of antithrombotic therapies in spine surgery. Spine J. 2009;9(12). doi:10.1016/j.spinee.2009.09.005
  14. Gould MK, Garcia DA, Wren SM, et al. Prevention of VTE in nonorthopedic surgical patients. Antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest. 2012;141(2 SUPPL.). doi:10.1378/chest.11-2297
  15. Eskildsen SM, Moll S, Lim MR. An algorithmic approach to venous thromboembolism prophylaxis in spine surgery. J Spinal Disord Tech. 2015;28(8). doi:10.1097/BSD.0000000000000321
  16. Louie P, Harada G, Harrop J, et al. Perioperative Anticoagulation Management in Spine Surgery: Initial Findings From the AO Spine Anticoagulation Global Survey. Glob Spine J. 2020;10(5). doi:10.1177/2192568219897598