Meralgia paresthetica: diagnosis and treatment.

Meralgia paresthetica is a symptom complex that includes numbness, paresthesias, and pain in the anterolateral thigh, which may result from either an entrapment neuropathy or a neuroma of the lateral femoral cutaneous nerve (LFCN). The condition can be differentiated from other neurologic disorders by the typical exacerbating factors and the characteristic distribution of symptoms. The disease process can be either spontaneous or iatrogenic. The spontaneous form is usually mechanical in origin. The LFCN is subject to compression throughout its entire course. Injuries most commonly occur as the nerve exits the pelvis. The regional anatomy of the LFCN is highly varied and may account for its susceptibility to local trauma. Relief of pain and paresthesias after injection of a local anesthetic agent is helpful in establishing the diagnosis. If no improvement is found, proximal LFCN irritation should be sought. Idiopathic meralgia paresthetica usually improves with nonoperative modalities, such as removal of compressive agents, nonsteroidal anti-inflammatory drugs, and, if necessary, local corticosteroid injections. If intractable pain persists despite such measures, surgery can be considered, although whether neurolysis or transection is the procedure of choice is still controversial. Iatrogenic meralgia paresthetica has been found to occur after a number of orthopaedic procedures, such as anterior iliac-crest bone-graft harvesting and anterior pelvic procedures. Prone positioning for spine surgery has also been implicated. Variations in the anatomy of the LFCN about the anterior superior iliac spine may place the nerve at higher risk for damage. Although nonoperative management usually results in satisfactory results, efforts should be made to avoid injury at the time of surgery.