Venous Thromboembolism: A Comparison of Chronic Spinal Cord Injury and General Surgery Patients in a Metropolitan Veterans Affairs Hospital

Background: Venous thromboembolic events result in significant morbidity, mortality, and costly therapeutic interventions. As medical resource allocation strategies are becoming more pervasive, appropriate risk stratification and prophylactic regimens are essential. Previous studies have shown a decreased incidence of perioperative venous thromboembolism in the chronic spinal cord injury population. The question remains of whether chronic spinal cord injury is protective against venous thromboembolism. Methods: A retrospective review of all cases involving chronic spinal cord injury patients who underwent plastic and reconstructive surgery operations (n = 424) and general surgery patients (n = 777) with a primary outcome of deep venous thrombosis or pulmonary embolism within 90 days of surgery was performed. Results: The incidence of postoperative deep venous thrombosis in the control and spinal cord injury groups was 1.7 percent and 0.2 percent, respectively (p = 0.027). However, such significance was not observed with regard to postoperative pulmonary embolism incidence (p = 0.070). Collectively, the incidence of postoperative venous thromboembolism-specifically, deep venous thrombosis or pulmonary embolism-was significantly greater in the general surgery population (p = 0.014). A nearly 10-fold increased risk of venous thromboembolism was seen among the control group (1.9 percent versus 0.2 percent) despite administration of optimal prophylaxis. Conclusions: This study demonstrates a profoundly low incidence of venous thromboembolism among chronic spinal cord injury patients compared with general surgery patients. Future efforts to elucidate how chronic spinal cord injury confers a protective mechanism may potentially influence the evolution of venous thromboembolism prevention guidelines, and spark the development of alternative prophylactic agents or customized application of prevention efforts.