Comparison of rivaroxaban and parnaparin for preventing venous thromboembolism after lumbar spine surgery

Safety and efficacy of apixaban vs. enoxaparin in thromboprophylaxis after spinal stenosis and degenerative spine surgery

INTRODUCTION

Degenerative spine surgeries often require postoperative immobilization or reduced mobility, predisposing patients to the formation of thrombosis and higher risk of thromboembolic complications. Despite the significance of this issue, there remains a lack of consensus on the optimal anticoagulant agent for postoperative thromboprophylaxis in spinal stenosis and degenerative spine surgeries. Low molecular weight heparins and direct Xa inhibitors represent two anticoagulant groups with high chemoprophylactic potential.

METHODS

This study included a prospective cohort of patients undergoing posterior decompressive surgery with or without instrumentation for degenerative spine disease and/or spinal stenosis. Patients receiving postoperative prophylactic Enoxaparin and Apixaban were selected to evaluate the rate of complications, as assessed by Clavien-Dindo classification, thromboembolic events, and 30-day mortality, readmission, and reoperation rate between the two anticoagulants.

RESULTS

130 patients were included in the analysis. 65 patients received Apixaban and Enoxaparin in each group. Mean age of the participants was 57.6±11.0. 83.1% underwent laminectomy and posterior spinal fusion, while 22 patients underwent decompressive surgery only. The incidence of venous thromboembolism (P-value=0.403), deep vein thrombosis (p-value=0.999), hematoma formation (p-value=0.403), surgical site infection (p-value=0.901), readmission (p-value=0.545), reoperation (p=0.510), mortality (p=0.648), and complications rate (p-value=0.232) were not statistically different between Enoxaparin and Apixaban.

DISCUSSION

Both Apixaban and Enoxaparin may be viable options for postoperative thromboprophylaxis in spine surgeries with comparable efficacy and safety profile. Future research endeavors should investigate the efficacy of these agents in comparison to placebo in a randomized setting.

Chemical prophylaxis and venous thromboembolism following elective spinal surgery: A systematic review and meta-analysis

Background

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is a potentially devastating complication after surgery. Spine surgery is associated with an increased risk of postoperative bleeding, such as spinal epidural hematomas (SEH), which complicates the use of anticoagulation. Despite this dilemma, there is a lack of consensus around perioperative VTE prophylaxis. This systematic review investigates the relationship between chemoprophylaxis and the incidence rates of VTE and SEH in the elective spine surgical population.

Methods

A comprehensive literature search was performed using PubMed, Embase, and Cochrane databases to identify studies published after 2,000 that compared VTE chemoprophylaxis use in elective spine surgery. Studies involving patients aged < 18 years or with known trauma, cancer, or spinal cord injuries were excluded. Pooled incidence rates of VTE and SEH were calculated for all eligible studies, and meta-analyses were performed to assess the relationship between chemoprophylaxis and the incidences of VTE and SEH.

Results

Nineteen studies met our eligibility criteria, comprising a total of 220,932 patients. The overall pooled incidence of VTE was 3.2%, including 3.3% for DVT and 0.4% for PE. A comparison of VTE incidence between patients that did and did not receive chemoprophylaxis was not statistically significant (OR 0.97, p=.95, 95% CI 0.43-2.19). The overall pooled incidence of SEH was 0.4%, and there was also no significant difference between patients that did and did not receive chemoprophylaxis (OR 1.57, p=.06, 95% CI 0.99-2.50).

Conclusions

The use of perioperative chemoprophylaxis may not significantly alter rates of VTE or SEH in the elective spine surgery population. This review highlights the need for additional randomized controlled trials to better define the risks and benefits of specific chemoprophylactic protocols in various subpopulations of elective spine surgery.

An Updated Systematic Review and Meta-analysis of the Impact of Graduated Compression Stockings in Addition to Pharmacological Thromboprophylaxis for Prevention of Venous Thromboembolism in Surgical Inpatients

OBJECTIVE

To compare the rate of venous thromboembolism (VTE) in surgical inpatients with pharmacological thromboprophylaxis and additional graduated compression stockings (GCSs) versus pharmacological thromboprophylaxis alone.

BACKGROUND

Surgical inpatients have elevated VTE risk; recent studies cast doubt on whether GCS confers additional protection against VTE, compared with pharmacological thromboprophylaxis alone.

METHODS

The review followed "Preferred Reporting Items for Systematic Reviews and Meta-analyses" guidelines using a registered protocol (CRD42017062655). The MEDLINE and Embase databases were searched up to November 2022. Randomized trials reporting VTE rate after surgical procedures, utilizing pharmacological thromboprophylaxis, with or without GCS, were included. The rates of deep venous thrombosis (DVT), pulmonary embolism, and VTE-related mortality were pooled through fixed and random effects.

RESULTS

In a head-to-head meta-analysis, the risk of DVT for GCS and pharmacological thromboprophylaxis was 0.85 (95% CI: 0.54-1.36) versus for pharmacological thromboprophylaxis alone (2 studies, 70 events, 2653 participants). The risk of DVT in pooled trial arms for GCS and pharmacological thromboprophylaxis was 0.54 (95% CI: 0.23-1.25) versus pharmacological thromboprophylaxis alone (33 trial arms, 1228 events, 14,108 participants). The risk of pulmonary embolism for GCS and pharmacological prophylaxis versus pharmacological prophylaxis alone was 0.71 (95% CI: 0.0-30.0) (27 trial arms, 32 events, 11,472 participants). There were no between-group differences in VTE-related mortality (27 trial arms, 3 events, 12,982 participants).

CONCLUSIONS

Evidence from head-to-head meta-analysis and pooled trial arms demonstrates no additional benefit for GCS in preventing VTE and VTE-related mortality. GCS confer a risk of skin complications and an economic burden; current evidence does not support their use for surgical inpatients.

Narrative Review of Antiplatelet and Anticoagulant Medications for Venous Thromboembolism Prevention in Spine Surgery

STUDY DESIGN

This was a narrative review.

OBJECTIVE

The objective of this study was to identify commonly utilized venous thromboembolism (VTE) prophylactic measures, spine surgeon perspective, and provide pharmacologic recommendations from the literature.

SUMMARY OF BACKGROUND DATA

Considered a preventable cause of morbidity and mortality, VTE remains an important iatrogenic diagnosis of concern. Reported rates of VTE following spine surgery vary widely (0.3%-31.0%).

MATERIALS AND METHODS

A MEDLINE query identified literature reporting on VTE prevention and outcomes in the setting of spine surgery. Findings extracted from the included articles were summarized in a narrative review format to identify salient aspects of the current literature.

RESULTS

Sixty articles were summarized. Many anticoagulation medications that are described in the literature target factors involved in the coagulation cascade common pathway including aspirin and other antiplatelet medications, heparins, and warfarin. Newer direct inhibitors of thrombin and factor Xa are now being utilized for VTE prevention, although with limited use specifically in spine surgery.

CONCLUSIONS

Perioperative management of antiplatelet and anticoagulation medications in spine surgery requires evidence-based protocols that can account for patient comorbidities and surgery-specific features. Future studies should prospectively focus on establishing stronger recommendations based on pathology, surgical indications, patient comorbidities, region of the spine, and broad surgical intervention to enable effective prophylaxis for VTE.

LEVEL OF EVIDENCE

Level II.

THE USE OF CHEMOPROPHYLAXIS OR NOT FOR DVT IN SPINE SURGERY: A SYSTEMATIC REVIEW

ABSTRACT Objective: To compare pharmacological and non-pharmacological prophylaxis in elective spine surgery to determine the risks of DVT, PTE, and epidural hematoma (EH) in both groups, as well as their respective treatment effectiveness. Methods: Systematic review and meta-analysis based on systematically searched articles, using combinations of MeSH terms related to chemoprophylaxis and non-chemoprophylaxis for prevention of deep vein thrombosis and pulmonary embolism in elective spine surgery. Adult patients were eligible for inclusion in the study, except for those with trauma, spinal cord injury, neoplasms, or those using vena cava filters. Results: Five studies were selected for this systematic review and meta-analysis: 3 retrospective studies, 1 prospective study, and 1 case series. Data analysis showed that 4.64% of patients treated with chemoprophylaxis had an unfavorable outcome regarding DVT, while this outcome occurred in 1.14% of patients not treated with chemoprophylaxis (p=0.001). Among patients using chemoprophylaxis, only 0.1% developed epidural hematoma and 0.38% developed PTE. Among those on non-pharmaceutical prophylaxis, 0.04% had EH (p=0.11) and 0.42% had PTE (p=0.45). Conclusions: No benefits were found for chemoprophylaxis as compared to non-chemoprophylaxis in preventing DVT in elective spine surgery, nor was there an increased risk of epidural hematoma or fatal thromboembolic events. Level of evidence III; Therapeutic studies; Investigation of treatment results.

Is there consensus on the perioperative management of Xa inhibitors in patients undergoing elective spine surgery?-A survey of current spine surgeon practices

BACKGROUND

Factor Xa inhibitors (Xai) are an increasingly common consideration in perioperative anticoagulation management. However, there no existing guidelines established for use in Spine Surgery. This survey study aims to capture current practice trends regarding the perioperative management of Xai among spine surgeons.

METHODS

An 11-question survey was sent to all surgeon members of 3 spinal surgery societies. Responses were remitted anonymously. Questions characterized the background and experience of the respondent and inquired into their current perioperative Xai and other anticoagulant management. Questions were all single-best option, multiple-choice.

RESULTS

A total of 116 surveys were received. Twenty-six (22.4%) were from neurosurgeons and 90 (77.6%) were from orthopedic surgeons. Practiced preoperative Xai hold length tended to be longer than recommended by the respondent's medical colleagues. Only 65.2% (P≤0.0001) of respondents practiced in agreement with the recommendations of their medical colleagues. Postoperative Xai holds trended toward longer holds than that of other anticoagulants with 37.9% (P=0.0125) of respondents showed differences within their own practice between length of Xai hold and length of other anticoagulant holds. One out of four respondents reported noticing a change in the rate of perioperative bleeding complications among Xai patients. Despite reported increased bleeding issues, only 39% of those who noted this increase in bleeding complications reported they would hold a Xai longer than other anticoagulants.

CONCLUSIONS

There exists a wide range of recommended and practiced chronic anticoagulant hold lengths. This inconsistency likely highlights conflicting risk aversion among surgeons, between complications which are viewed as medical (i.e., thromboembolism and stroke) vs. surgical (i.e., compressive hematoma). Yet, survey responses suggest the length of Xai hold times did not necessarily reflect the surgeon's experience with postoperative bleeding complications in Xai patients. These inconsistent practices highlight the need for further research that can establish guidelines for perioperative management of Xai patients undergoing spine surgery.

KEYWORDS

Anticoagulants; factor Xa inhibitors (factor Xai); spine; orthopedic surgery; neurosurgery.

Venous Thromboembolism Prophylaxis in Elective Spine Surgery

STUDY DESIGN

Review.

OBJECTIVE

Venothromboembolic (VTE) complications, composed of deep vein thrombosis and pulmonary embolism are commonly observed in the perioperative setting. There are approximately 500 000 postoperative VTE cases annually in the United States and orthopedic procedures contribute significantly to this incidence. Data on the use of VTE prophylaxis in elective spinal surgery is sparse. This review aims to provide an updated consensus within the literature defining the risk factors, diagnosis, and the safety profile of routine use of pharmacological prophylaxis for VTE in elective spine surgery patients.

METHODS

A comprehensive review of the literature and compilation of findings relating to current identified risk factors for VTE, diagnostic methods, and prophylactic intervention and safety in elective spine surgery.

RESULTS

VTE prophylaxis use is still widely contested in elective spine surgery patients. The outlined benefits of mechanical prophylaxis compared with chemical prophylaxis varies among practitioners.

CONCLUSION

The benefits of any form of VTE prophylaxis continues to remain a controversial topic in the elective spine surgery setting. A specific set of guidelines for implementing prophylaxis is yet to be determined. As more risk factors for thromboembolic events are identified, the complexity surrounding intervention selection increases. The benefits of prophylaxis must also continue to be balanced against the increased risk of bleeding events and neurologic injury.

Consensus statement for perioperative care in lumbar spinal fusion: Enhanced Recovery After Surgery (ERAS®) Society recommendations

BACKGROUND

Enhanced Recovery After Surgery (ERAS) evidence-based protocols for perioperative care have led to improvements in outcomes in numerous surgical areas, through multimodal optimization of patient pathway, reduction of complications, improved patient experience and reduction in the length of stay. ERAS represent a relatively new paradigm in spine surgery.

PURPOSE

This multidisciplinary consensus review summarizes the literature and proposes recommendations for the perioperative care of patients undergoing lumbar fusion surgery with an ERAS program.

STUDY DESIGN

This is a review article.

METHODS

Under the impetus of the ERAS® society, a multidisciplinary guideline development group was constituted by bringing together international experts involved in the practice of ERAS and spine surgery. This group identified 22 ERAS items for lumbar fusion. A systematic search in the English language was performed in MEDLINE, Embase, and Cochrane Central Register of Controlled Trials. Systematic reviews, randomized controlled trials, and cohort studies were included, and the evidence was graded according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. Consensus recommendation was reached by the group after a critical appraisal of the literature.

RESULTS

Two hundred fifty-six articles were included to develop the consensus statements for 22 ERAS items; one ERAS item (prehabilitation) was excluded from the final summary due to very poor quality and conflicting evidence in lumbar spinal fusion. From these remaining 21 ERAS items, 28 recommendations were included. All recommendations on ERAS protocol items are based on the best available evidence. These included nine preoperative, eleven intraoperative, and six postoperative recommendations. They span topics from preoperative patient education and nutritional evaluation, intraoperative anesthetic and surgical techniques, and postoperative multimodal analgesic strategies. The level of evidence for the use of each recommendation is presented.

CONCLUSION

Based on the best evidence available for each ERAS item within the multidisciplinary perioperative care pathways, the ERAS® Society presents this comprehensive consensus review for perioperative care in lumbar fusion.

Are the correct outcomes being measured in studies of oral anticoagulants? A systematic survey

INTRODUCTION

Oral anticoagulant (OAC) intervention trials have typically included clinical event outcomes. However, there is no standard list of outcomes to be used in OAC research. This study aimed to describe and classify the outcomes used in recent prospective clinical studies involving OACs.

MATERIALS AND METHODS

We searched MEDLINE, EMBASE, and CINAHL databases from January 2009 to July 2019 for prospective studies with an intervention or control group that included one or more oral anticoagulants. We abstracted details about each included study and the outcomes used from the study report and its accompanying protocol. Using the Core Outcome Measures in Effectiveness Trials (COMET) Initiative recommendations, we categorised each outcome into one of five domains (mortality/survival, physiological/clinical, life impact, resource use, and adverse events). Our primary outcome was the prevalence of use of an outcome domain across studies.

RESULTS

We included 70 prospective studies, including 52 randomized controlled trials and 18 prospective cohort studies. A total of 121 different outcomes were reported. The COMET domains were represented in the 70 studies as follows: mortality (63/70, 90.0%); physiological/clinical domain (70/70, 100%), life impact domain (43/70, 61.4%), resource use domain (26/70, 37.1%), and adverse events domain (55/70, 78.6%).

CONCLUSION

Outcome reporting in prospective studies of OACs more frequently concentrates on mortality, physiological/clinical domains, and adverse events compared to life impact and resource utilization domains, the latter uncommonly used. A priority for future research includes developing a core outcome set (COS) for OAC research that represents all domains.

Risk of intracranial hemorrhage with direct oral anticoagulants: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

We performed a systematic review and meta-analysis to compare the risk of intracranial hemorrhage (ICH) between direct oral anticoagulants (DOACs) and other antithrombotic drugs in detail across all diseases.

METHODS

PubMed, EMBASE, Web of Science, and the Cochrane Library were searched for relevant randomized controlled trials (RCTs). Heterogeneity was examined using the I² statistic. Risk ratio (RR) and 95% confidence interval (CI) were calculated using random-effects meta-analysis.

RESULTS

Fifty-five RCTs were included in this meta-analysis. Compared with vitamin K antagonists (VKAs), dabigatran reduced the risk of ICH by 60% (RR 0.40; 95% CI 0.28-0.57), apixaban by 57% (RR 0.43; 95% CI 0.31-0.58), edoxaban by 56% (RR 0.44; 95% CI 0.29-0.67) and rivaroxaban by 41% (RR 0.59; 95%CI 0.44-0.80). Compared with low-molecular-weight heparins (LMWHs), apixaban, edoxaban and rivaroxaban had a similar risk of ICH. Compared with aspirin, dabigatran and apixaban had a similar risk of ICH, while rivaroxaban posed an increased risk of ICH (RR 2.12; 95% CI 1.31-3.44). For secondary prevention stroke, DOACs reduced the risk of ICH by 46% compared with warfarin (RR 0.54; 95% CI [0.42-0.70]) and had a similar risk of ICH compared with aspirin.

CONCLUSION

All DOACs had a lower risk of ICH than VKAs. In terms of the risk of ICH, DOACs were overall as safe as LMWHs, and apixaban and dabigatran were as safe as aspirin, but rivaroxaban was not. For secondary prevention stroke, the risk of ICH with DOACs was overall lower than warfarin and similar to aspirin, but it should be noted that compared with aspirin, rivaroxaban may increase the risk of ICH. This is the first pair-wise meta-analysis that compares the risk of ICH between DOACs and other antithrombotic drugs in detail across all diseases, which may have certain significance for patients with high risk of ICH to choose antithrombotic drugs in clinical practice.

Thromboprophylaxis for orthopedic surgery; An updated meta-analysis

BACKGROUND

Venous thromboembolism (VTE) is a serious complication of orthopedic surgery. Low molecular weight heparin (LMWH) has been the standard of care for thromboprophylaxis in this population. However, direct oral anticoagulants (DOACs) are increasingly being used as alternatives.

OBJECTIVE

To assess the efficacy and safety of DOACs versus LMWH for thromboprophylaxis in orthopedic surgery.

METHODS

We searched MEDLINE, Embase, and the Cochrane Collaboration Central Register of Controlled Trials from inception until April 2020, for randomized controlled trials (RCTs) comparing DOACs with LMWH for thromboprophylaxis in orthopedic surgery.

RESULTS

Twenty-five RCTs met inclusion criteria, including 40,438 patients, with a mean age of 68 years and 50% were males. Compared to LMWH, DOACs were associated with a significant reduction of major VTE; defined as the composite events of proximal deep vein thrombosis (DVT), pulmonary embolism (PE), and VTE-related mortality (RR 0.33; 95% CI: 0.20-0.53; P<0.01), and total DVT (RR: 0.59; 95% CI: 0.48-0.73; P<0.01), but not PE (RR 0.81; 95% CI: 0.49-1.34; P=0.42). There was no statistically significant difference between both groups on the incidence of major bleeding (RR 0.99; 95% CI: 0.77-1.27; P=0.92), clinically relevant non-major bleeding (RR 1.04; 95% CI: 0.92-1.17; P=0.52), all-cause mortality (RR 1.06; 95% CI: 0.64-1.76; P=0.83), VTE-related mortality (RR 0.84; 95% CI: 0.40-1.74; P=0.64) and bleeding-related mortality (RR 1.24; 95% CI: 0.30-5.18; P=0.77).

CONCLUSION

For patients undergoing orthopedic surgery, thromboprophylaxis with DOACs is associated with a significant reduction of major VTE and DVT, compared to LMWH. Safety outcomes were not significantly different between both treatment groups.

Use of Fondaparinux Following Elective Lumbar Spine Surgery Is Associated With a Reduction in Symptomatic Venous Thromboembolism

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To assess the impact of fondaparinux on venous thromboembolism (VTE) following elective lumbar spine surgery in high-risk patients.

METHODS

Matched patient cohorts who did or did not receive inpatient fondaparinux starting postoperative day 2 following elective lumbar spine surgery were compared. All patients received 1 month of acetyl salicylic acid 325 mg following discharge. The primary outcome was a symptomatic DVT (deep vein thrombosis) or PE (pulmonary embolus) within 30 days of surgery. Secondary outcomes included prolonged wound drainage, epidural hematoma, and transfusion.

RESULTS

A significantly higher number of DVTs were diagnosed in the group that did not receive inpatient VTE prophylaxis (3/102, 2.9%) compared with the fondaparinux group (0/275, 0%, P = .02). Increased wound drainage was seen in 18.5% of patients administered fondaparinux, compared with 25.5% of untreated patients (P = .15). Deep infections were equivalent (2.2% with fondaparinux vs 4.9% control, P = .18). No epidural hematomas were noted, and the number of transfusions after postoperative day 2 and 90-day return to operating room rates were equivalent.

CONCLUSIONS

Patients receiving fondaparinux had lower rates of symptomatic DVT and PE and a favorable complication profile when compared with matched controls. The retrospective nature of this work limits the safety and efficacy claims that can be made about the use of fondaparinux to prevent VTE in elective lumbar spine surgery patients. Importantly, this work highlights the potential safety of this regimen, permitting future high-quality trials.

Perioperative Anticoagulation Management in Spine Surgery: Initial Findings From the AO Spine Anticoagulation Global Survey

STUDY DESIGN

Cross-sectional, international survey.

OBJECTIVES

This study addressed the global perspectives concerning perioperative use of pharmacologic thromboprophylaxis during spine surgery along with its risks and benefits.

METHODS

A questionnaire was designed and implemented by expert members in the AO Spine community. The survey was distributed to AO Spine's spine surgeon members (N = 3805). Data included surgeon demographic information, type and region of practice, anticoagulation principles, different patient scenarios, and comorbidities.

RESULTS

A total of 316 (8.3% response rate) spine surgeons completed the survey, representing 64 different countries. Completed surveys were primarily from Europe (31.7%), South/Latin America (19.9%), and Asia (18.4%). Surgeons tended to be 35 to 44 years old (42.1%), fellowship-trained (74.7%), and orthopedic surgeons (65.5%) from academic institutions (39.6%). Most surgeons (70.3%) used routine anticoagulation risk stratification, irrespective of geographic location. However, significant differences were seen between continents with anticoagulation initiation and cessation methodology. Specifically, the length of a procedure (P = .036) and patient body mass index (P = .008) were perceived differently when deciding to begin anticoagulation, while the importance of medical clearance (P < .001) and reference to literature (P = .035) differed during cessation. For specific techniques, most providers noted use of mobilization, low-molecular-weight heparin, and mechanical prophylaxis beginning on postoperative 0 to 1 days. Conversely, bridging regimens were bimodal in distribution, with providers electing anticoagulant initiation on postoperative 0 to 1 days or days 5-6.

CONCLUSION

This survey highlights the heterogeneity of spine care and accentuates geographical variations. Furthermore, it identifies the difficulty in providing consistent perioperative anticoagulation recommendations to patients, as there remains no widely accepted, definitive literature of evidence or guidelines.

Thromboprophylaxis in elective spinal surgery: A protocol for systematic review

BACKGROUND

Venous thromboembolism (VTE) is a serious, sometimes life-threatening complication that can occur following spine surgery. The incidence of VTE, and the optimal type and timing of thromboprophylaxis for this complication in elective spine surgery is a matter of debate.

OBJECTIVE

To perform a systematic review with the aim of clarifying the efficacy and adverse effects of mechanical and chemical prophylaxis for preventing thromboembolic complications in elective spine surgery for conditions other than trauma and malignant disease.

METHODS/DESIGN

A search strategy of related articles up to March 2018 was designed and executed in Medline and Embase.

PATIENTS

adolescents (>10 years) and adults undergoing elective surgery for spinal deformity or degenerative disease (from C1 to S1).

INTERVENTION

Perioperative mechanical and chemical thromboprophylaxis. Studies could be randomized controlled trials or observational studies that reported data on any relevant clinical outcomes.

RESULTS

In total, 2451 uniquecitations were identified and 35 studies were ultimately included in the systematic review. The overall mean incidence of complications was 3.7% for deep venous thrombosis, 0.0% for pulmonary embolism, and 3.7% for bleeding in chemoprophylaxis group; 2.9% for deep venous thrombosis, 0.4% for pulmonary embolism and 0.0% for bleeding in mechanoprophylaxis; and 0.7% for deep venous thrombosis, 0.1% for pulmonary embolism and 0.2% for bleeding in mixed prophylaxis group with no specific data on these rates for the type of patient and type and location of surgery. None of the articles retrieved provided information on the adolescent population.

DISCUSSION AND CONCLUSIONS

The poor design and high variability among the studies regarding characteristics of study population, details of interventions, and definitions of outcomes, determines a low quality of the available evidence and limits the interpretation of the results. We were unable to identify a clear advantage of one type of thromboprophylaxis over the other, although there was an increased risk of bleeding with chemoprophylaxis, which could favor the use of mechanoprophylaxis in this scenario.

Venous Thromboembolism Prophylaxis in Spine Surgery

Venous thromboembolism (VTE) is a source of morbidity and mortality in patients undergoing orthopaedic surgery. A substantial body of literature supports the use of VTE prophylactic agents in patients undergoing lower extremity surgery. Treatment options include early mobilization, mechanical prophylaxis via pneumatic compression devices, pharmacologic agents, and venous filters. No consensus has been established regarding utilization or timing of VTE prophylaxis measures after spine surgery. The risk of VTE in patients undergoing spine surgery is not well characterized and varies substantially by the procedure and degree of neurologic compromise. In addition, the risk of clinically notable VTE must be weighed against the risk of postoperative bleeding and epidural hematoma after spine surgery. A standardized approach to VTE prophylaxis in patients undergoing spine surgery must take into account the available studies of risk factors, choice of prophylactic agents, and timing of prophylaxis.

Risk factors and pharmacologic prophylaxis for venous thromboembolism in elective spine surgery

BACKGROUND CONTEXT

Venous thromboembolism (VTE) is a known complication after spine surgery, but prophylaxis guidelines are ambiguous for patients undergoing elective spine surgery.

PURPOSE

The objective of this study was to characterize the incidence and risk factors for VTE and the association of pharmacologic prophylaxis with VTE and bleeding complications after elective spine surgery.

STUDY DESIGN/SETTING

This is a retrospective cohort study of patients undergoing elective spine surgery in the National Surgical Quality Improvement Program (NSQIP) database and a retrospective cohort analysis at an academic medical center.

PATIENT SAMPLE

This study included 109,609 patients in the NSQIP database from 2005 to 2014 and 2,855 patients at the authors' institution from January 2013 to March 2016 who underwent elective spine surgery.

OUTCOME MEASURES

The incidence and risk factors for VTE were assessed in both cohorts based on the NSQIP criteria. The incidence of bleeding complications requiring reoperation was assessed based on operative reports in the institutional cohort.

MATERIALS AND METHODS

Associations of patient and procedure factors with VTE were characterized in the NSQIP population. In the single-institution cohort, in addition to NSQIP variables, a chart review was completed to determine the use of VTE prophylaxis, the history of prior VTE, and the incidence of hematoma requiring reoperation. The association of patient and procedure variables, including pharmacologic prophylaxis and history of prior VTE, with VTE and hematoma requiring reoperation were determined with multivariate regression.

RESULTS

Among 109,609 elective spine surgery patients in NSQIP, independent risk factors for VTE were greater age, male gender, increasing body mass index, dependent functional status, lumbar spine surgery, longer operative time, perioperative blood transfusion, longer length of stay, and other postoperative complications. There were 2,855 patients included in the institutional cohort. Pharmacologic prophylaxis was performed in 56.3% of the institutional patients, of whom 97.1% received unfractionated heparin. When controlling for patient and procedural variables, pharmacologic prophylaxis did not significantly influence the rate of VTE, but was associated with a significant increase in hematoma requiring a return to the operating room (relative risk=7.37, p=.048).

CONCLUSIONS

Pharmacologic prophylaxis, primarily with unfractionated heparin, after elective spine surgery was not associated with a significant reduction in VTE. However, there was a significant increase in postoperative hematoma requiring reoperation among patients undergoing prophylaxis. This raises questions about the routine use of unfractionated heparin for VTE prophylaxis and supports the need for further consideration of risks and benefits of chemoprophylaxis after elective spine surgery.

Thromboprophylaxis in Spinal Surgery

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

Determine the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) in spinal surgery patients receiving no thromboprophylaxis, mechanoprophylaxis, and chemoprophylaxis.

SUMMARY OF BACKGROUND DATA

The incidence of thromboembolic complications after spinal surgery is not well established. Although a variety of effective mechanical and chemical thromboprophylaxis interventions exist, their role in spinal surgery remains unclear. Spine surgeons are faced with the difficult decision of balancing the risk of death from a thromboembolic complication against the risk of permanent neurological damage from an epidural hematoma (EDH).

METHODS

The Medline database was queried using combinations of the terms related to the aforementioned subject matter. Articles meeting our predetermined inclusion criteria were reviewed and relevant data extracted. Meta-analyses were created using a random-effects model for incidence of DVT and PE by type of thromboprophylaxis, method of screening, and study type.

RESULTS

Twenty-eight articles were included in the final analyses. The higher mean incidence of DVT and PE in the mechanoprophylaxis group (DVT: 1%, PE: 0.81%) compared to the chemoprophylaxis group (DVT: 0.85%, PE: 0.58%) was not observed to be statistically significant. Six percent of PEs was fatal; the rate of EDHs was 0.3%. The incidence of DVT was higher in prospective studies (1.4%) compared to retrospective studies (0.61%); the incidence of DVT was not affected by whether the study screened only symptomatic patients.

CONCLUSION

Although the incidence of DVT and PE was relatively low regardless of prophylaxis type, the true incidence is difficult to determine given the heterogeneous nature of the small number of studies available in the literature. Our findings suggest there may be a role for chemoprophylaxis given the relatively high rate of fatal PE. Future studies are needed to determine which patient population would benefit most from chemoprophylaxis.

LEVEL OF EVIDENCE

2.

Timing and risks of chemoprophylaxis after spinal surgery: a single-center experience with 6869 consecutive patients

OBJECTIVE

Venous thromboembolism (VTE) after spinal surgery is a major cause of morbidity, but chemoprophylactic anticoagulation can prevent it. However, there is variability in the timing and use of chemoprophylactic anticoagulation after spine surgery, particularly given surgeons’ concerns for spinal epidural hematomas. The goal of this study was to provide insight into the safety, efficacy, and timing of anticoagulation therapy after spinal surgery.

METHODS

The authors retrospectively examined records from 6869 consecutive spinal surgeries performed in their departments at Northwestern University. Data on patient demographics, surgery, hospital course, timing of chemoprophylaxis, and complications, including deep venous thrombosis (DVT), pulmonary embolism (PE), and spinal epidural hematomas requiring evacuation, were collected. Data from the patients who received chemoprophylaxis (n = 1904) were compared with those of patients who did not (n = 4965). The timing of chemoprophylaxis, the rate of VTEs, and the incidence of spinal epidural hematomas were analyzed.

RESULTS

The chemoprophylaxis group had more risk factors, including greater age (59.70 vs 51.86 years, respectively; p < 0.001), longer surgery (278.59 vs 145.66 minutes, respectively; p < 0.001), higher estimated blood loss (995 vs 448 ml, respectively; p < 0.001), more comorbid diagnoses (2.69 vs 1.89, respectively; p < 0.001), history of VTE (5.8% vs 2.1%, respectively; p < 0.001), and a higher number were undergoing fusion surgery (46.1% vs 24.7%, respectively; p < 0.001). The prevalence of VTE was higher in the chemoprophylaxis group (3.62% vs 2.03%, respectively; p < 0.001). The median time to VTE occurrence was shorter in the nonchemoprophylaxis group (3.6 vs 6.8 days, respectively; p = 0.0003, log-rank test; hazard ratio 0.685 [0.505–0.926]), and the peak prevalence of VTE occurred in the first 3 postoperative days in the nonchemoprophylaxis group. The average time of initiation of chemoprophylaxis was 1.46 days after surgery. The rates of epidural hematoma were 0.20% (n = 4) in the chemoprophylaxis group and 0.18% (n = 9) in the nonchemoprophylaxis group (p = 0.622).

CONCLUSIONS

The risks of spinal epidural hematoma among patients who receive chemoprophylaxis and those who do not are low and equivalent. Administering anticoagulation therapy from 1 day before to 3 days after surgery is safe for patients at high risk for VTE.