Duration of Sciatic Nerve Block After Injection of Local Anesthetic In or Around the Nerve

This study was designed to assess whether the injection of local anesthetic into the nerve (intraneural), as opposed to around it (perineural), leads to longer anesthesia and analgesia of the leg. Some reports of accidental intraneural injection mention an extremely long duration. When different drugs and doses were evaluated in a clinical trial of intraneural injection, a longer-than-expected duration was reported. The investigators will compare the two types of injection using the same drug, so as to determine if there is an actual difference in duration.