Lateral Femoral Cutaneous Nerve Entrapment

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Lateral Femoral Cutaneous Nerve Entrapment

The lateral femoral cutaneous nerve (LFCN) is a pure sensory nerve that is vulnerable to compression. Its course begins at the lumbosacral plexus, travels down through the retroperitoneum, under the inguinal ligament, and into the subcutaneous tissue of the thigh. Meralgia paraesthetica (MP), also known as Bernhardt-Roth syndrome refers to nerve compression causing the clinical syndrome of pain, dysaesthesia, or both in the anterolateral thigh. MP was first described by Werner Hager in 1885. It was later named "meralgia," with the etymology stemming from the Greek words "meros" (thigh), and "algos" (pain). This article deals with the clinical syndrome of LFCN entrapment. Full discussion of injection treatments and the anatomy are discussed elsewhere (See Lateral Femoral Cutaneous Nerve Injection and Lateral Femoral Cutaneous Nerve.)

Epidemiology and Risk Factors

Nontraumatic MP has an incidence of 3.4–4.3/10,000 person-years. It is significantly linked to carpal tunnel syndrome, pregnancy, obesity, and diabetes mellitus (DM). Diabetes mellitus confers a 7 times higher rate of MP. Conversely, for those without DM, patients with MP are twice as likely to be lateral diagnosed with DM. There is a male predominance.

Clinical Features

History

Symptoms are classically subacute on onset, and involve burning pain, dysaesthesia (paraesthesia and hypoaesthesia), or both. The affected area is the anterolateral thigh. Pain can be felt anywhere from the anterior to the lateral hip, the anterior and lateral thigh, and distally down to the anterior knee. Some patients feel a coldness, deep muscle aching, profoundly reduced sensation, or hair loss in the area due to stroking it. The symptoms are purely sensory in nature, because the LFCN doesn't have any motor fibres. Symptoms tend to be aggravated by prolonged standing and walking. Relieving factors are typically sitting down, but some patients describe sitting worsening the pain. Patients may modify their gait to reduce symptoms and develop secondary hip, knee, and calf pain.

The occupational, exercise, and trauma history that is relevant to LFCNE is below.

• Compression
  • Obesity
  • Pregnancy
  • Abdominal masses (uterine myoma, retroperitoneal lipofibrosarcoma)
  • Ascites, large abdomen
  • Tight garments or seat belts, especially in thin individuals
  • Leg length discrepancy
  • Lumbar herniated disk
  • Psoas tumor/infection/spasm
• Trauma
  • “Hip-checked”
• Surgery
  • Laparoscopic appendectomy, cholecystectomy, hernia repair
  • Iliac crest graft
  • Lumbar sympathetic block or neurolysis
  • Femoral artery catheterization
  • Occurs in 20 % of spinal surgeries
  • Total hip arthroplasty
  • Ilioinguinal repair of a pelvic fracture
• Infection/inflammation
  • Diabetes mellitus
  • Periostitis of the ilium
  • Retrocecal tumor
  • Appendicitis
• Exercise
  • Strenuous abdominal or lower body exercise

Treatment

Lateral Femoral Cutaneous Nerve Injection

Literature Review

Literature Review

Reviews from the last 7 years: review articles, free review articles, systematic reviews, meta-analyses, NCBI Bookshelf

Articles from all years: PubMed search, Google Scholar search.

TRIP Database: clinical publications about evidence-based medicine.

Other Wikis: Radiopaedia, Wikipedia Search, Wikipedia I Feel Lucky, Orthobullets,