Meralgia is pain in the area of ​​the femoral-cutaneous nerve which is accompanied by tingling, numbness and decreased sensitivity along this nerve path. Often caused by compression of the nerve, meralgia is treated by treating the cause. At the same time, drug solutions help reduce pain. 

Definition

Meralgia paresthetica, also called femoro-cutaneous neuralgia, is a neurological condition. It groups together all the symptoms encountered following an injury to the tissues constituting the femorocutaneous nerve located on the outside of the thigh.

Causes

Meralgia can be of mechanical origin. It then results from compression of the femoro-cutaneous nerve along its path which can be caused by various factors:

• Obesity
• Pregnancy
• Tight clothing (jeans, police uniforms, military armor)
• Seat belts
• Scoliosis
• Hematoma on the psoas iliac muscle
• Trauma
• Muscle spasms
• Unequal leg length
• Rapid weight loss

In some cases, meralgia can be caused by an act or measure performed or prescribed by a health professional:

• Post-surgical complication after hip joint replacement or spine surgery
• More rarely following a bone graft taken from the iliac bone, an appendectomy, a cesarean section with epidural or obstetric or gynecological surgery.

Finally, meralgia can be a complication of endocrine diseases such as diabetes or infectious diseases such as typhus.

Diagnostic

The diagnosis of meralgia is complicated because the condition mimics neurological symptoms (numbness, tingling, etc.) which are also associated with other common causes of pain on the outside of the thigh such as lumbar stenosis, a herniated disc or compression of a nerve root. A differential diagnosis should be conducted to rule out these options.

Along with the differential diagnosis, the practitioner can conduct a series of specific clinical tests:

• Pelvic compression
• A neurodynamic test
• Compression neuropalpation

Meralgia can also be diagnosed using neurophysiological studies such as nerve conduction tests or evoked somatosensory potential. The latter examines the nerve pathways from the arms and legs by measuring the change in electrical potential produced by the nervous system in response to external stimulation.

More recently, magnetic resonance neurography has been used to capture live images of nerves.

At the same time, practitioners can also opt for an infiltration test of the femoro-cutaneous nerve. This practice involves putting the nerve to sleep using numbing products (for example, 1% Lidocaine). In this case, the test is considered positive if the patient has immediate relief which lasts 30 to 40 minutes after the injection.

The people concerned

Although it can occur at all ages, meralgia mainly affects individuals aged 30 to 40 years with an incidence of 4.3 cases per 10 patients per year. For people with diabetes, this incidence climbs to 000 cases per 24.7. The disease affects men more than women.

Risk factors

The most common factors favoring meralgia are:

• obesity
• Diabetes
• Wearing tight clothes

Meralgia is a sharp, intense pain, with twitching, which sits on the path of the femoro-cutaneous nerve. Pain sometimes occurs when the person is sitting or standing for a long time.

The pain is often accompanied by a series of symptoms located on the outside of the thigh:

• Tingling
• burns
• Numbness
• Decreased sensitivity along the path of the nerve

Treatment of meralgia is often that of the cause.

At the same time, analgesics (aspirin if there is no contraindication, paracetamol) can be prescribed to calm the pain. For intractable pain, antiepileptics (such as clonazepam) are a possible alternative. Some medical teams also offer cortisone injections, or local anesthetics (procaine, lidocaine) in contact with the anterosuperior iliac spine. Finally, a supply of vitamin B1 (thiamine) reduces pain while improving nervous functioning.

In some cases, osteopathy and functional rehabilitation bring good results.

More rarely, the treatment of meralgia may require neurolysis of the femorocutaneous nerve. This surgery involves freeing the stuck nerve, or cutting part of the nerve.

To prevent meralgia, wearing tight clothing at the waist should be avoided.