26. Does anticoagulant thromboprophylaxis increase bleeding complications in spinal surgery and spinal cord injury? A systematic review and meta-analysis

Abstract

BACKGROUND CONTEXT The routine use of anticoagulants for the prevention of venothromboembolism in spinal patients is controversial and the risk benefit analysis is poorly described. PURPOSE The objective of this systematic review and meta-analysis is to collate the current evidence and quantify the risk of bleeding associated with anticoagulant thromboprophylaxis in the spinal patient, both in the elective and trauma settings. STUDY DESIGN/SETTING Spinal surgery and trauma inpatients. PATIENT SAMPLE A total of 92,406 patients. OUTCOME MEASURES Outcomes of interest were the number of patients with spinal epidural hematoma or wound hemorrhagic complications that were associated with neurological symptoms or required treatment, including either operative or nonoperative intervention. METHODS MEDLINE, EMBASE, Cochrane Trial Register databases and the grey literature were searched. Data were pooled via a meta-analysis from randomized trials and cohort studies comparing the rates of spinal epidural hematoma and wound hemorrhagic complications in spinal surgery patients receiving low molecular weight and low dose unfractionated heparin (LMWH/UFH) thromboprophylaxis and those not anticoagulated. The risk of bias within individual studies and across all the studies was assessed using the Cochrane risk of bias tools and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool, respectively. RESULTS The meta-analysis included 11 studies of 92,406 patients with 1,007 relevant bleeding complications. A significant increase in the risk of extra-spinal wound hemorrhage was found in patients receiving perioperative LMWH/UFH thromboprophylaxis compared to controls (OR 1.56, 95% CI 1.18 - 2.06, p=0.002, I2=8%). The same comparison revealed no significant increase in the risk of spinal epidural hemorrhage (OR 1.20, 95% CI 0.65 - 2.22, p=0.56, I2=0%). The quality of evidence for both outcomes was low. There was insufficient data to conclude about the risk of hemorrhagic complications in spinal trauma and in patients receiving nonheparin thromboprophylaxis agents. CONCLUSIONS Our results raise concern about a possible increased risk of extraspinal wound hemorrhage associated with LMWH/LDUFH thromboprophylaxis in spinal surgery. FDA DEVICE/DRUG STATUS low molecular weight heparin (Approved for this indication), low dose unfractionated heparin (Approved for this indication)