The risk of thromboembolism in patients undergoing colorectal surgery.

Patients undergoing colorectal surgical procedures are at a moderately high risk for the development of thromboembolic events. Possible reasons may be that the procedures tend to be long in duration, patients are often placed in the lithotomy position, a pelvic dissection may be performed, and the indication is often inflammatory bowel disease or cancer. While prophylaxis with low dose heparin is effective at reducing this risk, approximately 10% of patients may still develop a thromboembolic event. Results on the effectiveness of low molecular weight heparin in this cohort of patients are pending.