339 - Non-surgical management of intraneural fibular ganglion related foot drop. Two case reports

Friday, February 23, 2024

5:00 PM – 6:30 PM EDT

Presenting Author(s)

BB

Barent A.G. Bradt, DO

Resident Physician
Wayne State University/ Detroit Medical Center
Traverse City, Michigan, United States

Co-Author(s)

IA

Ian Ackers, DO, PhD

Resident
Michigan State University/Sparrow Hospital
Lansing, Michigan, United States
MA

Michael T. Andary, MD

Professor
MSU Rehabilitation
East Lansing, Michigan, United States
MS

Mathew J. Seidel, n/a

Undergraduate Assistant
Oakland University
Troy, Michigan, United States
GS

Geoffrey K. Seidel, MD

Physician
Wayne State University, Michigan State University
Troy, Michigan, United States

Case Diagnosis: Foot drop is a common condition evaluated by physiatrists clinically and electrodiagnostically. An uncommon cause of foot drop is fibular nerve ganglion, often associated with arthritis, at the proximal tibiofibular joint. Current literature discusses only surgical management of this condition. We present two cases of successful non-surgical management of a suspected intraneural fibular ganglion related foot drop.

Case Description: Both patients presented with leg weakness, paresthesias of the dorsum of the foot, worse with activity. Examination revealed foot drop with heel walking, 4/5 weakness in tibialis anterior, peroneal muscles, extensor hallucis longus with dorsal foot and first web space sensory loss. Knee X-ray was normal. Electrodiagnostic assessment revealed abnormalities of fibular nerve across the knee. Needle EMG revealed denervation with chronic motor unit changes isolated in clinically weak muscles distal to the knee. Knee MRI demonstrated cyst-like enlargement of the fibular nerve suspected to be an intraneural ganglion. Treatment included rest, an oral prednisone taper, and NSAIDS. Both cases had full motor recovery and full sensory recovery. MRI images and EMG data will be presented.

Discussions: Fibular neuropathy secondary to ganglion cysts at the proximal tibio-fibular joint are relatively uncommon but should be considered in the differential diagnosis. To our knowledge these are the first reported cases of a presumed intraneural ganglion cyst causing fibular neuropathy that was successfully treated conservatively. Further investigation into the conservative management of fibular neuropathy from ganglion cyst compression is needed.

Conclusions: Electromyography can be useful to localize lesions related to foot drop. In this case the limited axon loss allowed for a conservative management decision for activity modification rather than more interventional treatment.