Anatomical variations of the lateral femoral cutaneous nerve and the consequences for surgery.

PURPOSE: This two-part study was undertaken to (a) determine the course and variations of the lateral femoral cutaneous nerve in a cadaver study and (b) develop prospectively the preoperative protocol to diminish the possibility of a postoperative meralgia paresthetica; the latter was achieved by reviewing the patient series retrospectively for complaints of a lateral femoral cutaneous nerve (LFCN) lesion and by studying the relation of the course of the LFCN and meralgia paresthetica.

METHODS: Anatomical studies were performed on 200 recently deceased patients. After exploring the LFCN from its origin to the inguinal region to determine its course, we classified 149 patients as "normal" and fifty-one as abnormal. We then identified eighty-two patients who, between 1989 and 1994, experienced LFCN lesion as a complication of pelvic surgery following an ilioinguinal approach.

RESULTS: Thirty-seven of these patients reported altered sensation for several years postoperatively (minimum follow-up one year), including eleven patients whose complaints persisted. In five of these cases, symptoms prompted an eventual exploration of the nerve, and nerve entrapment was confirmed. Between 1994 and 1996, perioperative care intended to lessen the chance of future LFCN problems was administered to forty patients. Thirty-three patients underwent neurolysis, and seven underwent nerve transection because an LFCN lesion occurred during the operation. Within a twelve-month follow-up period, no meralgia paresthetica was noted.

CONCLUSION: The practical importance of the present study lies in alerting the surgeon to a possible anatomical variation of the LFCN in about 25 percent of the patient population. It also confirms that the new perioperative protocol lowers the incidence of meralgia paresthetica.