Also known as lateral femoral cutaneous nerve entrapment, meralgia paresthetica is a benign condition caused by the compression of this nerve at any point along its course.
It can present with a burning sensation, paraesthesia, or hyperesthesia over the distribution of the nerve on the anterolateral aspect of the thigh. The patients usually rub the area as they describe the pain. The sensory loss is quite distinct and borders can be demarcated easily. The presentation is usually restricted to sensory symptoms due to the pure sensory nature of the nerve [6].
Neurologic exam usually reveals abnormal sensations of pinprick and touch in the distribution of the nerve. The rest of the lower limb examination (motor and tendon reflexes) is normal.
The diagnosis can be made clinically if the distribution and presentation are classic with absence of other neurologic abnormalities of the lower leg. Other tests may be required to rule out other associated factors.
This condition is usually self-limiting in most patients. Most patients respond to conservative management. The treatment is mainly directed towards reducing the pressure over the area of compression; for instance, in obese patients, weight loss is indicated.
If the problem persists then drugs such as carbamazepine or gabapentin can be used to reduce the discomfort.
Surgery is rarely used but if indicated, decompression may be done. The success rates are variable. Nerve blocks may also be tried in unresponsive cases. There have been reports of use of radio-frequency ablation in resistant cases.
Treatment of associated factors such as diabetes is also advised [8] [9] [10].
The prognosis is excellent in over 90% of the patients. Improvements are seen if the right causes and associated factors are found and dealt with appropriately. Some patient may have persistent mild loss of sensation that is not uncomfortable.
Most of the patients have compression of the nerve on its course as it goes below the inguinal ligament. There are a number of causes or precipitants that may cause compression including tight belts and garments, scars near the Poupart’s ligament and pregnancy. There have been noted associations with obesity and old age. Iatrogenic causes secondary to surgery near the Poupart’s ligament and spinal surgery have been noted [2].
The incidence has been reported at 4.3 per 10,000 patient years. The incidence is much higher in the diabetic population with rates as high as 240 per 100,000 patient years. There is no gender or race predominance. The incidence rises with advancing age [3].
The anatomy and course of the nerve is important in understanding the condition. The lateral femoral cutaneous nerve has root innervations from L2-3. It runs along the lateral border of the psoas muscle to the lateral part of the inguinal ligament. It then passes in a tunnel made by the Poupart’s ligament and anterior superior iliac spine. It then crosses over into the thigh. This is the most common site of entrapment [4] [5].
Advice on avoidance of tight garments and weight loss strategies should be encouraged to prevent the development of meralgia paresthetica and other nerve compression syndromes.
Meralgia paresthetica (lateral femoral cutaneous nerve entrapment) is the term used to describe the clinical condition comprising of pain, dysesthesia or both of the area supplied by the nerve, particularly the lateral aspect of thigh. It is a benign condition usually caused by pressure on of the nerve [1].
Meralgia paresthetica is a condition when there is abnormal uncomfortable burning sensation, increased touch sensation or reduced sensation on the outer side of the thigh. The condition is not serious and does not indicate an ominous back problems. It is caused by pressure on the nerve that supplies the affected area. The compression may be due to tight clothes, garments or fat in obese people. It is also much more common in diabetics. There is also an association with pregnancy. It may also be caused by surgery around the groin area.
In the majority of the patients, the condition goes away on its own when the inciting event has been dealt with. In those cases that do not respond, drugs may be given to reduce the discomfort. The final step in difficult cases is surgery to relieve the pressure on the nerve.