Sciatic nerve block by the anterior and posterior approach for operations on the lower extremity. A comparative study.

The results of the analgesic block of the lower extremity by means of an anterior (150 patients) or a posterior (114 patients) approach to the sciatic nerve, associated to a "3 in 1 block" were compared. The anterior approach technique was associated with a higher incidence of failures, insufficient analgesia and hence a higher demand for intraoperative analgesic and sedative drugs. Also tolerance to a pneumatic tourniquet over the proximal thigh was less than with the posterior approach. However, the sciatic nerve block by anterior approach granted a more prolonged analgesia. This technique was suitable for trauma patients immobilized in the supine position, for patients with skeletal traction on Zupinger frame, both for surgery and for closed reduction of lower extremity fractures.