While femoral and sciatic blocks have been used effectively to provide anesthesia for operations on the lower leg and foot, block anesthesia for procedures on or above the knee has not been used extensively because of the necessity to also block the obturator and lateral femoral cutaneous nerves. Even in experienced hands, if blockade of all four nerves is attempted, it requires a large number of injections and large volumes of local anesthetic; thus, not only may the failure rate be high but the complication rate as well. A reexamination of the anatomy would seem to indicate that the three nerves to the leg arising from the lumbar plexus can be blocked by a single injection, for the lumbar plexus arises in a fascial envelope, from which an extension accompanies the femoral nerve. Thus, if this fascial extension is identified by the production of a paresthesia of the femoral nerve and if a sufficient volume of anesthetic solution is injected to reach the plexus, anesthesia of all three nerves does result. Clinical experience has shown such a technic to be extremely effective, safe, and simple; and volume anesthesia studies have indicated that to block all three nerves consistently a minimum of 20 ml. of anesthetic must be utilized. On the other hand, additional studies showed that even with the use of volumes two or three times this minimum volume, anesthesia over the distribution of the sciatic nerve did not result; this nerve had to be blocked separately if anesthesia in that distribution was necessary.
|Original language||English (US)|
|Number of pages||8|
|Journal||Anesthesia and Analgesia|
|State||Published - Dec 1 1973|
ASJC Scopus subject areas
- Anesthesiology and Pain Medicine