Meralgia Paresthetica

What is meralgia paresthetica?

A mononeuropathy of a purely sensory nerve, presenting with “burning” pain and paresthesias over the thigh without muscle weakness.

Meralgia paresthetica results from dysfunction of the lateral femoral cutaneous nerve (LFCN), a nerve that transmits exclusively sensory information from the skin of the anterolateral/lateral thigh. The most common pathophysiologic mechanism is mechanical compression of the nerve as it passes beneath/through the inguinal ligament.

Key point: because the LFCN is a purely sensory nerve, meralgia paresthetica does not cause muscle weakness. If weakness, reflex changes, or atypical symptoms are present, evaluation for an alternative etiology is required.

How common is it & who is at risk?

It is more common in middle-aged adults and in conditions that increase pressure or mechanical friction at the level of the inguinal ligament.

Meralgia paresthetica most often occurs in the third to fourth decade of life and is typically unilateral. Risk factors include:

• External compression: belts, braces, tight trousers.
• Increased intra-abdominal pressure/volume: obesity, pregnancy, ascites.
• Metabolic/toxic factors: diabetes mellitus, alcohol use (and rarely toxic exposures).
• Post-operative states: groin surgery (e.g., hernia repair), iliac crest bone graft harvest, pelvic surgery.
• Operative positioning: prolonged prone positioning with pressure near the ASIS during spine surgery.

What is the anatomy of the lateral femoral cutaneous nerve (LFCN)?

Anatomic variations at the nerve’s exit beneath the inguinal ligament explain why some patients are more vulnerable to entrapment.

The LFCN typically arises from the L2–L3 roots of the lumbar plexus. It courses retroperitoneally, crosses the anterior surface of the iliacus muscle, and as it approaches the anterior superior iliac spine (ASIS), passes beneath the inguinal ligament into the thigh, through a fibrous tunnel.

Clinically important: the point of passage can vary substantially among individuals (e.g., more medial, more superficial, or dividing into one or more branches). These variations influence where the nerve is compressed and why certain surgical procedures or sites of external pressure affect patients differently.

What are the most common triggers and causes?

In most cases there is functional/mechanical entrapment, but in persistent symptoms other causes should be excluded.

Meralgia paresthetica is often idiopathic and associated with factors that produce acute or chronic mechanical irritation of the LFCN or increase its vulnerability:

• Compression from clothing/equipment (belts, harnesses, tight garments).
• Weight gain or conditions associated with increased intra-abdominal pressure.
• Diabetes and other metabolic disorders affecting peripheral nerves.
• Post-surgical states in the groin/pelvis or prolonged prone positioning.

If symptoms are persistent or “atypical,” alternative etiologies should be considered (e.g., lumbar radiculopathy or, rarely, an intrapelvic mass).

What are the symptoms and where are they located?

Symptoms are purely cutaneous: burning pain/numbness over the anterolateral thigh, often extending toward the knee.

Typical clinical features:

• Burning, “pins-and-needles,” or “electric” sensations over the anterolateral thigh.
• Numbness or decreased sensation in the same region.
• Discomfort may extend to the knee, but usually not below it.
• Often worsened by prolonged standing or activities that place tension on the nerve.
• Many patients improve with sitting, though in some symptoms may worsen.
• In some, pressure/percussion near the inguinal ligament may reproduce symptoms (positive Tinel sign).

Hallmark: no muscle weakness and no major neurologic deficits.

What can it be confused with (differential diagnosis)?

Accurate differentiation is essential, as other causes of lower-limb pain require entirely different management.

Conditions that may mimic it clinically:

• L2–L3 lumbar radiculopathy from disc herniation or stenosis.
• Femoral neuropathy (often with quadriceps weakness or reflex changes).
• Lumbar plexopathy (e.g., diabetic or post-surgical/hemorrhagic pelvic complications).
• Intrapelvic/retroperitoneal masses (compressive phenomena, rarely tumors).
• Orthopedic causes (e.g., hip pathology) when pain is vague or mixed.

Findings such as weakness, reflex changes, pronounced low-back pain with a classic radicular pattern, or urologic/gastrointestinal symptoms are not consistent with meralgia paresthetica and warrant further evaluation.

How is the diagnosis made in practice?

The diagnosis is primarily clinical: history, symptom localization, and neurologic examination.

Assessment includes:

• Focused history (tight belts/clothing, recent weight gain, pregnancy, diabetes, recent surgery).
• Clinical examination with sensory testing in the distribution of the LFCN.
• Confirmation of absence of muscle weakness and normal reflexes.
• Tenderness at the nerve’s passage near the inguinal ligament (and possibly a Tinel sign).

The characteristic presentation (purely sensory symptoms, well-defined distribution, no weakness) is usually sufficient to establish a confident diagnosis.

When is imaging or further evaluation needed?

In persistent, atypical, or worsening symptoms, the goal is to exclude alternative causes from the spine, pelvis, or another nerve.

Further evaluation is recommended when:

• Symptoms persist despite appropriate conservative measures.
• There are atypical features (extensive distribution, night pain, systemic symptoms).
• Weakness, reflex changes, or signs of radicular involvement are present.
• There is clinical suspicion of an intrapelvic/retroperitoneal cause.

Suggested investigations (case-by-case):

• Lumbar spine MRI to exclude disc herniation/stenosis mimicking L2–L3 radiculopathy.
• Pelvic/retroperitoneal imaging (ultrasound or MRI) if indicated.
• Laboratory testing for metabolic factors (e.g., diabetes) as appropriate.
• Electrodiagnostic studies (selected cases) to support the diagnosis or exclude another neuropathy.

What is conservative treatment (what can you do immediately)?

In most patients, improvement follows simple, targeted measures that reduce pressure on the nerve.

First-line practical steps:

• Avoid compression at the groin: looser clothing, no tight belts/harnesses.
• Weight reduction when obesity is present (gradual, realistic plan).
• Optimize metabolic factors (especially diabetes control).
• Activity modification that exacerbates symptoms (e.g., prolonged standing).
• Gentle physical therapy where appropriate (mobility/ergonomics), particularly if there is associated myofascial strain.

In a large proportion of patients, symptoms are mild and improve gradually. Post-operative/iatrogenic cases often show complete recovery over time with appropriate nerve off-loading.

What is the role of medications and local nerve blocks?

When neuropathic pain affects daily life, targeted non-surgical options are available.

Depending on symptom severity, options may include:

• Pharmacologic management of neuropathic pain, individualized by the treating physician.
• Local diagnostic/therapeutic nerve block of the LFCN with local anesthetic ± corticosteroid.

A nerve block can serve two purposes: (a) confirm that the LFCN is indeed the pain generator, and (b) provide meaningful relief to facilitate off-loading and rehabilitation.

If the presentation is not typical or there is suspicion of radiculopathy/another neuropathy, thorough evaluation should precede attribution of symptoms to meralgia paresthetica.

When do we consider surgery and what are the goals?

Surgical treatment is uncommon and reserved for symptoms that persist despite appropriate conservative care.

In most cases, conservative management is effective. Surgery may be discussed when:

• Symptoms are persistent and function-limiting despite appropriate therapy.
• Alternative diagnoses (radiculopathy, pelvic mass, other neuropathy) have been excluded.
• There is clear clinical correlation and, ideally, positive response to a diagnostic nerve block.

Surgical options (individualized):

• Neurolysis/decompression of the LFCN at the level of the inguinal ligament (release of fibrous bands/compressive structures).
• Neurectomy (transection of the nerve) in select cases: associated with high success rates, but results in permanent sensory loss over the anterolateral thigh.