During this procedure, a catheter is inserted behind the knee so that the lower branches of the sciatic nerve can be bathed in a continuous flow of anesthetic solution. Typically, it is used to numb the leg for surgery on the lower leg, ankle and foot and to manage pain following surgery.
In preparation for the procedure, the patient is positioned to expose the back of the knee. The physician determines the precise entry point for the needle on the back of the knee. The tissue at the entry point is numbed with an injection of local anesthesia.
The physician will use a needle connected to an electric nerve stimulator to ensure correct placement of the catheter. The needle is carefully advanced through the numbed skin and guided to the sciatic nerve. The nerve stimulator administers weak electric pulses. When these pulses cause the muscles of the foot to twitch, the needle is positioned correctly.
Once the needle is in place, the physician pushes a thin catheter through the needle and down to the nerve. The needle is removed, and the catheter is secured against the leg.
The anesthetic solution may now be injected as needed through the catheter, bathing the nerve and temporarily blocking sensation in the lower leg, ankle and foot. The catheter may be left in place for several days to alleviate pain.