Sciatic nerve block: a new midfemoral lateral approach. Benefit of the combination with a (3 in 1) block for invasive knee surgery

Objective: To describe a new midfemoral lateral approach for the sciatic nerve block. Its combination with the "3 in 1" block was tested for postoperative analgesia following major surgery of the knee. Study design: Descriptive, anatomical and clinical study prospective. Patients: After testing in four unembalmed corpses the new approach was applied to 42 ASA 1-2 patients, in combination with a continuous "3 in 1" block. Methods: The new approach was analysed for reliability of the surface landmarks (a line drawn from the posterior margin of the greater trochanter towards the knee and parallel to the femur) and block extent assessed on the foot. Its combination with the "3 in 1" block was evaluated with a visual analogue scale (VAS) scoring, for postoperative analgesia after total knee arthroplasty. Results: The sciatic nerve was located in less than 10 min. A block of the sciatic nerve was fully achieved in all patients. Its median duration was 16 h. The median VAS score at rest was 0 mm (sciatic bloc + continuous block "3 in 1"), but increased to 40 mm (block "3 in 1" alone). Conclusion: The new lateral midfemoral sciatic block is easy to master. Combined with a continuous "3 in 1" block, it provides excellent analgesia during the early postoperative period after major surgery of the knee. (C) 2000 Editions scientifiques et medicates Elsevier SAS.