A Comparison of Two Injection Locations in Obese Patients Having Lower Leg/Foot Surgery

Overview

One technique for the nerve block involves injecting the numbing medicine where the nerve is together (higher up in the back of the thigh). The other technique involves injecting the numbing medicine where the nerve splits into two parts. By injecting numbing medication around the nerve(s), there will be less pain after the procedure. It is thought that the numbing medicine will be easier to inject in the group that the nerves are split. It is expected that subjects may need less pain medication and have lower pain ratings in this group too.

The purpose of this study is to compare two different techniques for placement of nerve blocks for your foot or ankle procedure. A nerve block involves injecting numbing medications around a nerve to decrease pain after surgery. An ultrasound machine is often used to help see the nerve before injecting the numbing medicine. When an ultrasound machine is used during a block it is called an ultrasound-guided block. Many studies of ultrasound-guided nerve blocks have involved mostly thin patients, especially from foreign countries. This study is different because the investigators are looking at patients living in America with a body mass index (a measure of the amount of body fat a person has) of more than 35. The Sciatic nerve is a large nerve that provides most of the feeling and all of the movement to the foot and ankle. The nerve travels under the back of the leg, and splits into two smaller nerves slightly above the knee.

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