Anticoagulation in Elective Spine Cases

Rates of Hematomas Versus Thromboembolic Disease

Dharani Rohit Thota, BA; Carlos A. Bagley, MD; Mazin Al Tamimi, MD; Paul A. Nakonezny, PhD; Michael Van Hal, MD


Spine. 2021;46(13):901-906. 

In This Article

Abstract and Introduction


Study Design: Retrospective cohort study with propensity matched cohorts.

Objective: The purpose of this study was to evaluate the association of anticoagulation with VTE and hematoma complications after spine surgery.

Summary of Background Data: One of the major complications of surgery is VTE which can range in presentation. Spine surgery is an especially complex balance between minimizing the risk of a VTE event and also the increased risk of a hematoma which can lead to devastating neurological outcomes.

Methods: The elective spine surgery cases at a single academic center between 2015 and 2017 were identified. A total of 3790 patients were initially identified. Two hundred sixty patients were excluded. The cohort was then matched using a propensity score. This matched a single patient who did not receive anticoagulation to a single patient who did within the institution. This left a total of 1776 patients with 888 patients in each arm.

Results: The incidence of VTE, PE, and unplanned reoperation for hematoma in this cohort was 0.96%, 0.34%, and 1.13%, respectively. Predicted odds of VTE and PE were not significantly different; however, the odds of an unplanned reoperation for hematoma (odds ratio [OR] = 7.535, 95% confidence interval [CI]: 2.004–28.340, P = 0.002) were greater for those who received pharmacological anticoagulation in our institutional cohort.

Conclusion: In this study, anticoagulation does not lead to lower rates of VTE events, but it increases the risk of symptomatic hematomas which require a return trip to the OR. While this was not a randomized controlled trial, we attempted to correct for this with propensity matching. Future randomized control trials would be needed.

Level of Evidence: 3


One of the major complications of surgery is venous thromboembolism (VTE) which can range in presentation from a relatively asymptomatic blood clot in the extremity to a life-threatening pulmonary embolism (PE). These thankfully are very rare events.[1] Traditionally deep vein thrombosis (DVT), while not inherently dangerous, has been used as a risk factor and predictor of the more feared and deadly PE. While all surgical specialties have to balance the risks and benefits of anticoagulation after surgery, spine surgery is an especially delicate balance between properly preventing and minimizing the risk of a thromboembolic event along with the risk of a hematoma at the surgical site which can result in devastating neurological consequences. These can be anywhere from pain, weakness, bowel and bladder dysfunction, and even paralysis. There have been many approaches aimed at achieving this balance; however, little consensus exists in the spine literature on this very important issue.

When studying rare events, an aggregate sample can shed light on the factors and rates that otherwise appear to be random and coincidental. The incidence and risk factors for VTE have been reported using national databases of surgeries.[2–6] One of the most well-known of these databases is the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP).

Our study aimed to evaluate our institutional experience with anticoagulation. We hypothesized that pharmacologic anticoagulation would increase the rates of bleeding complications requiring reoperation, but not change the risk of VTE in our patient population. We secondarily sought to compare our intuitional experience with anticoagulation to the larger NSQIP database. In particular, we evaluated the rates of our institution for PE and return to OR as markers vis-à-vis a similar patient population in the larger NSQIP dataset.