Venous thromboembolism occurs frequently in patients undergoing brain tumor surgery despite prophylaxis.

Most Neurosurgical Service patients at our hospital receive venous thromboembolism prophylaxis. In 1995-96, the rate of clinically overt venous thromboembolism was 3.7% among patients undergoing neurosurgery. However, rates were much higher when craniotomy was undertaken for brain tumor. Of 497 who underwent craniotomy for primary (429) or metastatic (68) brain tumor, 47 (9.5%) developed clinically overt venous thromboembolism: 7.5% after primary brain tumor resection and 19% after craniotomy for metastatic cancer. The high rate of venous thromboembolism in craniotomy patients with brain tumor warrants study of alternative measures for preventing thrombus, such as prophylaxis with low molecular weight heparin.