1319 - Double Trouble: A Case of Meralgia paresthetica and Facetogenic back pain

Patient presented with chronic, aching, and intermittently sharp bilateral low back pain radiating into the anterior thighs (R >L) beginning during pregnancy several years prior. Symptoms were triggered by prolonged standing, with no known alleviating factors. Physical examination revealed tenderness over bilateral facet joints and paravertebral muscles, positive facet loading R >L, negative dural tension signs, intact strength, reflexes, and gait. Pain was suspected to be facet-mediated with referred anterior thigh pain. She completed a course of PT without low back pain relief and had persistent anterior thigh numbness. Repeat exam was notable for decreased sensation over the right anterior thigh and a positive Tinel sign over the right LFCN. Given these findings, she subsequently underwent right LFCN hydrodissection for suspected meralgia paresthetica with 80% relief of right anterior thigh pain. MRI was notable for multilevel facet arthrosis (L3/4, L5/S1).

Discussions: Facet-mediated low back pain can radiate to the anterior thighs (L3-S1). In this case, the patient had meralgia paresthetica, a separate, co-contributing diagnosis manifesting as anterior thigh pain. It was on the basis of reassessment and comprehensive physical examination of this patient with persistent symptoms and poor response to PT that this diagnosis was made.

Conclusions: Lumbar pathologies have overlapping symptoms with peripheral neuropathies due to referred pain patterns. It is essential for the Physiatrist to perform a comprehensive exam, maintain a broad differential including multiple pain generators, and reassess response to treatment to ensure accurate diagnosis and treatment.