Anticoagulation in spinal surgery. A critical review of the literature.

OBJECTIVE: To determine the natural incidence of thromboembolic complications and the effect of thromboprophylaxis associated with elective spinal surgery. DATA SOURCES: A search of the MEDLINE database, using the key words anticoagulation, deep vein thrombosis (DVT) and spine, alone and in different combinations. Individual journals were also searched. Articles investigating the incidence or treatment (or both) of thromboembolism in elective spinal surgery were identified. STUDY SELECTION: Studies describing elective spinal surgery. The type of surgery, days of recumbency, methods of thromboprophylaxis, study design, surveillance methods, rates of DVT and pulmonary embolism (PE), and type and rates of complications of thromboprophylaxis were determined. DATA EXTRACTION: Single observer. DATA SYNTHESIS: Only 15 studies were found. Most were of poor statistical quality: 5 were level IV quality (nonrandomized, historic controls), 8 were level V quality (no controls, cases series), 1 was a level III study (nonrandomized, contemporaneous controls) and 1 was a level II study (small randomized study, moderate to high risk of error). The raw incidence of thromboembolic complications derived from these studies was 7.1% (14.1%) (mean [and SD]). However, because of the poor quality of these studies, this figure is suspect.
CONCLUSIONS: The true incidence of thromboembolic complication in spinal surgery remains unknown. Recommendations for thromboprophylaxis cannot be made from the findings of these studies. There is a need for a well-designed, randomized controlled study to define the efficacy of thromboprophylaxis in elective spinal surgery.