Hydrodissection as a therapeutic and diagnostic modality in treating peroneal nerve compression

A 51-year-old man presented with pain in the region of his left patellar tendon and fibular head. He had previously undergone three L5 epidural steroid injections and physical therapy without relief. Prior magnetic resonance imaging was significant only for fat pad impingement, and electromyography and nerve conduction studies were negative. Ultrasound demonstrated an enlarged peroneal nerve suggestive of peroneal nerve entrapment. Three ultrasound-guided hydrodissection procedures offered symptomatic improvement and identified an area posterior to the fibular head that was unable to be hydrodissected, indicating scar tissue causing peroneal nerve compression. The patient was referred for peroneal nerve decompression at the area of entrapment with complete symptom relief. This case is unique in describing the ability of hydrodissection to identify nerve compression not visualized with other diagnostic tests.