Brian Karamian, Tony Tannoury, Khoa Tran, Alexander R. Vaccaro.

Response/Recommendation: Following spine surgery,the rate of venous thromboembolism (VTE) is significantly higher in patients with incidental durotomy (almost 1.5 times) compared to patients without. Therefore, in patients with dural tears post spine surgery, vigorous VTE prophylaxis therapies should be considered.

Strength of Recommendation: Limited.

Rationale: Complications in spine surgery tend to occur in clusters as complex spinal pathologies lead to higher rate of successive undesirable events. Inadvertent dural tears during spine surgery are associated with increased in-hospital complications, health care burden, and readmission rates^1-3. In a retrospective analysis, Alluri et al., found that VTE occurred in 1.3% of patients with a dural tear in contrast to 0.9% of patients without (odds ratio [OR] 1.46, p < 0.001)⁴. Similarly, deep venous thrombosis (DVT) and pulmonary embolism (PE) occurred in 1% and 1% of patients with a dural tear and only in 0.7% and 0.7% of patients without durotomy (OR 1.36, p = 0.03 for DVT, OR 1.48, p = 0.01 for PE) respectively. This relationship was seen after matching specific demographic and comorbidity variables that were associated with VTE complications. Another observational cohort study by Durand et al., studied 86,212 patients who underwent spine surgery using the National Surgical Quality Improvement Program (NSQIP) dataset from 2012 to 2015⁵. The authors identified late-presenting dural tears (LPDT) using reoperation or readmission procedures defined by durotomy-specific Current Procedural Terminology (CPT) codes. After adjusting for patient and procedure-level factors, patients with LPDT had higher rates of surgical site infection (OR 2.54, p < 0.0001), wound disruption (OR 2.24, p < 0.0001), sepsis (OR 2.19, p < 0.0001), and VTE (OR 1.71, p < 0.0001). The authors suggested that predisposition of LPDT patients to wound infection and subsequent bacteremia may lead to higher risks of thromboembolic events⁶. Although the underlying pathogenesis of VTE development in sepsis remains unclear, the etiology is thought to be the result of several factors associated with dural tears including immobility and activation of thrombo-inflammatory pathways^7-9.

In another retrospective study using the Nationwide Inpatient Sample (NIS) database, Yoshihara et al., analyzed patient outcomes after incidental durotomies in cervical spine surgery¹. In this study, the mean hospital stay was 1.4 days longer in patients with dural tears than in those without (4.6 vs. 3.0 days, p < 0.001). Rates of neurologic (3.0 vs. 0.4 %, p < 0.001) complications (including transitory ischemic attack [TIA]/stroke) and PE (1.8 vs. 0.2%, p < 0.001) were significantly higher in the dural tear group.

Current postoperative managements of dural tears include subarachnoid lumbar drainage and/or postoperative bed rest, which can lead to extended immobilization and subsequent venous stasis, thereby increasing the odds of VTE^1,3,10-12. In a study investigating bedrest greater or less than 24 hours for incidental lumbar dural tear after laminectomy, there was a statistically significant increase in the incidence of medical complications in the bed rest group > 24 hours (p = 0.0003), which included greater rates of DVT (4.2 vs. 0%)¹³. However, this study was underpowered to statistically compare DVT rates.

In addition to postoperative immobility, increased rates of VTE in patients with dural tears may be attributed to increase in operative times. In a prospective cohort study of patients undergoing discectomy or laminectomy procedures, Smorgick et al., found that intraoperative repair of an incidental durotomy significantly increased operative duration (146 ± 59 vs. 110 ± 54 minutes; p = 0.0025)¹⁴. Another prospective, observational study by Weber et al., showed that an incidental dural tear prolonged surgical duration from 116 to 153 minutes (p < 0.0001) in patients undergoing elective spinal surgery for degenerative disorders of the cervical, thoracic, or lumbar spine¹⁵. Inflammation and endothelial damage that occurs during surgery, in combination to immobility associated with prolonged surgical duration, can initiate the clotting cascade, and increase thrombus formation^16-20. It has been shown that ischemia and venous stasis, which occur during surgery, can also lead to DVT formation via the upregulation of P-selectin and local prothrombotic microparticles^21,22. Few studies within the spine literature have investigated the direct effect of longer operative times on VTE risk²³. A prospective cohort study by Inoue et al., using indirect multidetector computed tomography (MDCT) in 100 patients undergoing spine surgery found that operative duration was not significantly different in patients that did (87) and did not (13) develop VTE²⁴. However, this study was limited in cohort size and surgical durations. Schoenfeld et al., using the NSQIP dataset investigating 27,730 patients determined that operative time exceeding 261 minutes was associated with risk of developing DVT (OR: 3.1 95% confidence interval [CI]: 2.3 – 4.1) and PE (OR: 3.15 95% CI: 2.1 – 4.7); however, this operative time is significantly higher than those found in previous incidental durotomy studies²⁵. Further studies focusing on the relationship between operating time and VTE risk in spine surgery are needed to determine a threshold duration of surgery.

The relationship between dural tears and VTE development is likely multifactorial and can be attributed to more complex pathology, longer operative duration, prolonged postoperative immobility, and risk for post-surgical infection. As such, a standardized approach to VTE prophylaxis in patients undergoing elective spine surgery must consider these risk factors as well as preexisting individual risk factors and comorbidities to guide appropriate post-operative prophylaxis. Currently, risk stratification tools such as the Rogers and Caprini scores do not adequately factor in intraoperative variables, such as the complexity of the procedure, especially in the event of a dural tear^26,27. Data in dural tear studies were also limited to in-hospital events which may underestimate the true incidences of complications and mortality. In view of these limitations, clinicians should factor in identifiable preoperative and intraoperative risk factors in the event of a dural tear to guide prophylactic measures such as more aggressive and evidence-based anticoagulation therapy for patients at risk.

References:

1.         Yoshihara H, Yoneoka D. Incidental dural tear in cervical spine surgery: analysis of a nationwide database. J Spinal Disord Tech. 2015;28(1):19-24. doi:10.1097/BSD.0000000000000071

2.         Takenaka S, Makino T, Sakai Y, et al. Dural tear is associated with an increased rate of other perioperative complications in primary lumbar spine surgery for degenerative diseases. Medicine (Baltimore). 2019;98(1):e13970. doi:10.1097/MD.0000000000013970

3.         Wang JC, Bohlman HH, Riew KD. Dural tears secondary to operations on the lumbar spine. Management and results after a two-year-minimum follow-up of eighty-eight patients. J Bone Joint Surg Am. 1998;80(12):1728-1732. doi:10.2106/00004623-199812000-00002

4.         Alluri R, Kang HP, Bouz G, Wang J, Hah RJ. The True Effect of a Lumbar Dural Tear on Complications and Cost. Spine (Phila Pa 1976). 2020;45(3):E155-E162. doi:10.1097/BRS.0000000000003213

5.         Durand WM, DePasse JM, Kuris EO, Yang J, Daniels AH. Late-presenting dural tear: incidence, risk factors, and associated complications. Spine J. 2018;18(11):2043-2050. doi:10.1016/j.spinee.2018.04.004

6.         Kaplan D, Casper TC, Elliott CG, et al. VTE Incidence and Risk Factors in Patients With Severe Sepsis and Septic Shock. Chest. 2015;148(5):1224-1230. doi:10.1378/chest.15-0287

7.         Attia J, Ray JG, Cook DJ, Douketis J, Ginsberg JS, Geerts WH. Deep vein thrombosis and its prevention in critically ill adults. Arch Intern Med. 2001;161(10):1268-1279. doi:10.1001/archinte.161.10.1268

8.         Cook D, Attia J, Weaver B, McDonald E, Meade M, Crowther M. Venous thromboembolic disease: an observational study in medical-surgical intensive care unit patients. J Crit Care. 2000;15(4):127-132. doi:10.1053/jcrc.2000.19224

9.         Ribic C, Lim W, Cook D, Crowther M. Low-molecular-weight heparin thromboprophylaxis in medical-surgical critically ill patients: a systematic review. J Crit Care. 2009;24(2):197-205. doi:10.1016/j.jcrc.2008.11.002

10.       Cammisa FP Jr, Girardi FP, Sangani PK, Parvataneni HK, Cadag S, Sandhu HS. Incidental durotomy in spine surgery. Spine (Phila Pa 1976). 2000;25(20):2663-2667. doi:10.1097/00007632-200010150-00019

11.       Eismont FJ, Wiesel SW, Rothman RH. Treatment of dural tears associated with spinal surgery. J Bone Joint Surg Am. 1981;63(7):1132-1136.

12.       Yang SD, Ding WY, Yang DL, et al. Prevalence and Risk Factors of Deep Vein Thrombosis in Patients Undergoing Lumbar Interbody Fusion Surgery: A Single-Center Cross-Sectional Study. Medicine (Baltimore). 2015;94(48):e2205. doi:10.1097/MD.0000000000002205

13.       Radcliff KE, Sidhu GD, Kepler CK, Gruskay J, Anderson DG, Hilibrand A, Albert TJ, Vaccaro AR (2012) Complications of Flat Bedrest Following Incidental Dural Repair. J Spinal Disord Tech (epub ahead of print)

14.       Smorgick Y, Baker KC, Herkowitz H, et al. Predisposing factors for dural tear in patients undergoing lumbar spine surgery. J Neurosurg Spine. 2015;22(5):483-486. doi:10.3171/2015.1.SPINE13864

15.       Weber C, Piek J, Gunawan D. Health care costs of incidental durotomies and postoperative cerebrospinal fluid leaks after elective spinal surgery. Eur Spine J. 2015;24(9):2065-2068. doi:10.1007/s00586-014-3504-7

16.       Jaffer AK, Barsoum WK, Krebs V, Hurbanek JG, Morra N, Brotman DJ. Duration of Anesthesia and Venous Thromboembolism After Hip and Knee Arthroplasty. Mayo Clinic Proceedings 2005;80:732–8. https://doi.org/10.4065/80.6.732.

17.       Xenos ES, Vargas HD, Davenport DL. Association of blood transfusion and venous thromboembolism after colorectal cancer resection. Thrombosis Research 2012;129:568–72. https://doi.org/10.1016/j.thromres.2011.07.047.

18.       Turpie AG, Chin BS, Lip GY. Venous thromboembolism: pathophysiology, clinical features, and prevention. BMJ 2002;325:887–90.

19.       Kroegel C, Reissig A. Principle Mechanisms Underlying Venous Thromboembolism: Epidemiology, Risk Factors, Pathophysiology and Pathogenesis. Respiration 2003;70:7–30. https://doi.org/10.1159/000068427.

20.       Peterson CW. Venous Thrombosis: An Overview. Pharmacotherapy: The Journal of Human Pharmacology and Drug Therapy 1986;6:12S-17S. https://doi.org/10.1002/j.1875-9114.1986.tb04025.x.

21.       Eppihimer MJ, Schaub RG. P-Selectin–Dependent Inhibition of Thrombosis During Venous Stasis. Arteriosclerosis, Thrombosis, and Vascular Biology 2000;20:2483–8. https://doi.org/10.1161/01.atv.20.11.2483.

22.       Wakefield TW, Myers DD, Henke PK. Mechanisms of Venous Thrombosis and Resolution. Arteriosclerosis, Thrombosis, and Vascular Biology 2008;28:387–91. https://doi.org/10.1161/atvbaha.108.162289.

23.       McLynn RP, Diaz-Collado PJ, Ottesen TD, et al. Risk factors and pharmacologic prophylaxis for venous thromboembolism in elective spine surgery. Spine J. 2018;18(6):970-978. doi:10.1016/j.spinee.2017.10.013

24.       Inoue H, Watanabe H, Okami H, Kimura A, Takeshita K. The Rate of Venous Thromboembolism Before and After Spine Surgery as Determined with Indirect Multidetector CT. JB JS Open Access. 2018;3(3):e0015. Published 2018 Aug 15. doi:10.2106/JBJS.OA.18.00015

25.       Schoenfeld AJ, Herzog JP, Dunn JC, Bader JO, Belmont PJ Jr. Patient-based and surgical characteristics associated with the acute development of deep venous thrombosis and pulmonary embolism after spine surgery. Spine (Phila Pa 1976). 2013;38(21):1892-1898. doi:10.1097/BRS.0b013e31829fc3a0

26.       Rogers SO, Kilaru RK, Hosokawa P, Henderson WG, Zinner MJ, Khuri SF. Multivariable Predictors of Postoperative Venous Thromboembolic Events after General and Vascular Surgery: Results from the Patient Safety in Surgery Study. Journal of the American College of Surgeons 2007;204:1211–21. https://doi.org/10.1016/j.jamcollsurg.2007.02.072.

27.       Bahl V, Hu HM, Henke PK, Wakefield TW, Campbell DA, Caprini JA. A Validation Study of a Retrospective Venous Thromboembolism Risk Scoring Method. Annals of Surgery 2010;251:344–50. https://doi.org/10.1097/SLA.0b013e3181b7fca6.