What is meralgia paresthetica?
Meralgia paresthetica results from compression, stretch or injury of the lateral femoral cutaneous nerve (LFCN). The nerve usually arises from L2–L3, crosses the pelvis and approaches the anterior superior iliac spine before entering the thigh.
The LFCN is sensory only. Typical symptoms are burning, tingling, numbness or pain from light clothing over the anterolateral thigh. True hip-flexion or knee-extension weakness is not typical and should prompt evaluation for another or additional lesion.
Causes and mechanism
External pressure from a belt, tight clothing, safety equipment or a seatbelt may irritate the nerve. Weight gain, pregnancy, diabetes, direct trauma, pelvic or hernia surgery, fixation near the ASIS and prolonged operative positioning are other possibilities. Sometimes no single cause is found.
After surgery, distinguishing scar entrapment, traction and a painful neuroma is important because the mechanism changes the reconstructive options.
Diagnosis and differential
Assessment maps the painful and numb area, looks for focal tenderness or a Tinel sign near the ASIS, and examines the spine, hip, strength and reflexes. Weakness, an altered knee reflex, substantial radicular back pain, deep groin pain or bilateral symptoms require a broader work-up.
Nerve studies may help but are not always definitive for a small sensory nerve with variable anatomy. Ultrasound can show the nerve, scar or a mass and guide a block; MRI is selected when the pattern is atypical.
Nonoperative treatment
Initial care removes external pressure and adapts activity, clothing and equipment. Weight management, diabetes control, tailored physiotherapy, medication for neuropathic pain and a nerve block may be appropriate. Many cases improve without surgery.
Surgical options
Persistent, disabling pain with a coherent examination and block response may lead to surgery after adequate conservative care. Options include decompression (neurolysis), medial transposition, neuroma excision with reconstruction when feasible, or selective neurectomy.
Decompression preserves the nerve and its sensory potential but symptoms may persist or recur. Neurectomy creates permanent numbness and may create another neuroma, so it is not an automatic choice.
When to seek assessment
Assessment is reasonable when pain persists, affects sleep or walking, begins after an operation or injury, or does not improve with conservative care. Weakness, bladder or bowel disturbance, fever, progressive night pain or unexplained weight loss are not typical of uncomplicated meralgia and require prompt medical review.
References
- Gomez YDC, Remotti E, Momah DU, et al. Meralgia Paresthetica Review: Update on Presentation, Pathophysiology, and Treatment. Orthopedic Reviews. 2023;15:71454. doi:10.52965/001c.71454
- Scholz C, Hohenhaus M, Pedro MT, et al. Meralgia paresthetica: relevance, diagnosis, and treatment. Deutsches Ärzteblatt International. 2023. doi:10.3238/arztebl.m2023.0170
- Lu VM, Burks SS, Heath RN, et al. Meralgia paresthetica treated by injection, decompression, and neurectomy. Journal of Neurosurgery. 2021;135(3):912–922. doi:10.3171/2020.7.JNS202191