Bilateral superficial peroneal nerve compression secondary to peroneus muscle herniations mimicking spinal...

Muscle herniation is an uncommon musculoskeletal condition that may present with non-specific lower limb symptoms and, in rare cases, result in peripheral nerve compression. We report the case of a 32-year-old woman who presented with a two-year history of progressive exertional bilateral lateral calf pain and dysesthesia initially suspected to represent neurogenic claudication. Lumbar spine magnetic resonance imaging (MRI) demonstrated no evidence of spinal canal stenosis, intervertebral disc herniation or nerve root compression. Subsequent MRI of both calves performed on a 1.5-T MRI system revealed bilateral focal fascial defects (measuring approximately 5-8 mm) within the lateral compartments with herniation of the peroneus longus muscles and associated compression of the superficial peroneal nerves at their fascial exit points. No vascular compression or alternative cause of nerve entrapment was identified. The patient underwent bilateral fasciotomy with superficial peroneal nerve decompression, resulting in complete resolution of symptoms. This case highlights an uncommon cause of bilateral exertional leg pain mimicking spinal claudication and emphasizes the importance of considering peripheral nerve entrapment secondary to muscle herniation when spinal investigations are inconclusive. MRI plays a key role in identifying fascial defects, muscle herniation and associated nerve compression, thereby facilitating appropriate surgical management.