Meralgia paraesthetica G57.1

Meralgia paraesthetica is considered the third most common bottleneck syndrome and therefore a possible cause of persistent pain in the outer and anterior thigh area (the lateral cutaneous femoral nerve, a purely cutaneous nerve, is affected). Meralgia is particularly common in the 30 to 40 age group and is often associated with diabetes, pregnancy and obesity. The pain usually arises spontaneously.

The causes of the development of compression syndrome can be mechanical or metabolic: mechanical reasons are considered too tight clothes, rapid weight gain and increased pressure in the abdomen. Metabolic causes are mainly due to diabetes and alcohol. Another, rarer cause can be an iatrogenic injury, i.e. caused by a surgical procedure (e.g. osteotomies).

Characteristic are paresthesias, i.e. superficial, stabbing, burning or tingling pains (often described as "running ants") on the outer - front thigh, in the area between hip and knee. Affected individuals can usually localize the paresthetic pain well. Thus, the diagnosis can either be made clinically or suspected. Another indication is an intensification of the pain when pressure is exerted on the inguinal ligament and often when stretching the leg backwards or when sitting.

Neurosurgical or conservative (avoidance of mechanical triggers).

However, surgical intervention is only necessary in the fewest cases. 85 to 90 percent of patients with meralgia paraesthetica can be successfully treated with conservative measures after correct diagnosis. The exact cause of the pain is always decisive in planning the therapy, which is why mechanical problems (e.g. pressure on the nerve due to too tight clothing, overweight) must also be taken into account as a first step.

The following therapies are used:

• Ultrasound-targeted local infiltration (e.g. with cortisone)
• Physical medicine (e.g. physiotherapy, massage etc.)
• Medicinal pain therapy
• Surgical intervention (neurolysis or neurectomy) is the last treatment option (in 10% of cases). Neurectomy effectively terminates pain conduction in 70-80%. Because the lateral cutaneal femoral nerve is a purely sensory nerve supplying skin and subcutaneous tissue, numbness remains on the lateral thigh. However, the neurectomy has no effect on motor function (Schuh A et al. 2017).

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2. Bernhardt M (1895) On isolated paresthesias occurring in the region of the external cutaneus femoris nerve. Neurol Zentralbl (Berlin) 14: 242-244
3. Joshi A et al (2004) An investigation of post-operative morbidity following iliac crest graft harvesting. Br Dent J 196: 167-171
4. Kitson J et al (2002) Meralgia paraesthetica. A complication of a patient-positioning device in total hip replacement. J Bone Joint Surg Br 84: 589-590
5. Roth WK (1895) Meralgia paraesthetica. Karger, Berlin
6. Schuh A et al (2017) Meralgia paraesthetica (Bernhardt-Roth syndrome). MMW Fortschr Med 159:66-68.