Any syndrome presenting clinically with numbness, paresthesias, and pain in the region over the anterolateral and lateral aspect of the thigh is suspicious of an inflammatory, degenerative lesion of the lateral femoral cutaneous nerve and is referred to as meralgia paresthetica.This syndrome may present clinically as sensations which are described as burning, or tingling, or hyperesthetic, or as numbness, or severe pain. Pain may occur after physical activity, or direct pressure against the thigh which is relieved by rest. A reduction in tactile sensibility may be demonstrated over the lateral aspect of the thigh.
Although it is commonly idiopathic, it may be due to kinking and constriction of the nerve where it exits the pelvis. The nerve arises from the posterior divisions of the second and third lumbar nerves and appears at the lateral border of the psoas muscle passing obliquely across the iliacus to the anterior superior iliac spine where it passes beneath the inquinal ligament where it proceeds down the anterolateral aspect of the thigh. If the nerve happens to penetrate between the two fasciculi of the inquinal ligament, when the hip is fully extended, it may be compressed by the posterior fibers of the ligament.
Although symptoms may persist for many months, they commonly subside over time. If the pain persists and is intolerable, conservative care involves application of interferential current with the electrodes placed with the point of intersection located at the position where the nerve emerges from the pelvis. The Davis procedure is recommended for actual clinical application of the current. Also, pulsed 2.5 percent lidocaine phonophoresis at 0.75 W/cm2 for 8-10 minutes p.r.n. for pain may also be applied, directing the cone of the ultrasonic beam at the point of emergence of the nerve from the pelvis. When at home, the patient may apply moist cryotherapy for 8-10 minutes at each treatment, allowing for 10 minute intervals prior to reapplying the moist cryotherapy p.r.n. over the area characteristic of the anatomic site where the nerve emerges from the pelvis.
In the unusual event that the pain should persist, referral for surgical division of the inquinal ligament, or neurectomy may become necessary.
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