Title : Peroneal nerve entrapment masquerading as lumbar stenosis: A diagnostic and therapeutic challenge
Abstract:
Foot drop can stem from central or peripheral neurological pathologies, requiring comprehensive evaluation to guide management. This case report describes the diagnostic journey of a 72-year-old female with a medical history of diabetes, hyperlipidemia, and hypertension, who was initially diagnosed with lumbar stenosis but later found to have peroneal nerve entrapment. This case reinforces the importance of a thorough clinical assessment in distinguishing between central and peripheral nerve disorders, which may have major implications for treatment and prognosis.
Case Description: A 72-year-old female presented with a 5-month history of progressive left foot weakness, pain, and numbness. Her medical history was notable for previous transient right foot drop. She described a progressive foot "drag" that evolved into a "flap" when walking and subsequent left side fall resulting in a severe foot drop. An initial MRI suggested L3-L4 disc protrusion and L5-S1 disc involvement, yet her symptomatology—pain radiating from the groin to the lateral thigh and calf, nocturnal cramping, and lateral calf numbness—was incongruent with radicular patterns. Lumbar radiograph findings were significant for L4 on L5 anterolisthesis without any change in flexion or extension. The patient had previously declined an ankle-foot orthosis and engaged only in limited physical therapy, which provided minimal relief. A meticulous neurological examination revealed complete foot drop with an inability to evert the foot, prompting further investigation. Electromyography confirmed peroneal nerve denervation without considerable lumbar radiculopathy. Her nonresponsive history to epidural steroid injections, gabapentin, celecoxib, and methylprednisolone emphasized the need for an alternative treatment strategy. Based on a comprehensive review of her history, clinical presentation, and diagnostic findings, a left peroneal nerve release was deemed the most appropriate intervention.
Discussion: This case exemplifies the intricacies involved in diagnosing neuro-orthopedic conditions. The comprehensive neurological assessment was critical in differentiating between lumbar spine pathology and peripheral neuropathy. This led to a targeted peroneal nerve decompression, and avoided an unnecessary invasive spinal decompression that was initially considered. The successful outcome—complete resolution of foot drop and return of lower extremity strength—validates this approach. Postoperatively, the patient's enhanced ambulatory capabilities and absence of complications speak to the efficacy and safety of the procedure. The case illustrates the essential role of clinical evaluation over imaging in certain neuropathic presentations. It also demonstrates the value of patient-centered decision-making, as the patient's refusal of an orthosis and limited response to conservative therapy guided the clinical team towards a surgical option, which ultimately proved to be curative. This case highlights the need for a high index of suspicion for potential peripheral nerve entrapment in patients with foot drop and lumbar spine abnormalities on imaging. It showcases the importance of a detailed clinical examination and the integration of diagnostic modalities to elucidate the true etiology of neurologic deficits.
Audience Take Away:
- Follows a 72-year-old initially diagnosed with lumbar stenosis but later found to have peroneal nerve entrapment, illustrating the complexities in differentiating central and peripheral nerve disorders.
- Underscores the indispensable role of clinical evaluation over imaging in neuropathic presentations, aligning with the need for suspicion of peripheral nerve entrapment in patients with foot drop and lumbar spine abnormalities.
- Highlights the intricacies in diagnosing neurological conditions, emphasizing the critical role of comprehensive neurological assessments in distinguishing between spinal pathology and peripheral neuropathy.
