Raveen R. Sugantharaj, DO
Resident Physician 4
UNC PMR
Durham, North Carolina, United States
Sidney Tucker, MD
Resident PGY3 Physician
UNC Hospitals – PM&R
Chapel Hill, North Carolina, United States
Presented with acute on chronic left medial heel/arch pain and numbness. Previous work-up for plantar fasciitis was negative and related treatments ineffective. Later she endorsed radicular symptoms and weakness of left leg which prompted urgent neurosurgical evaluation via NCS/EMG (EDx) to assess. Exam remarkable only for diminished sensation to light touch of medial foot. EDx study showed normal motor and sensory NCS except low SNAP amplitude of medial calcaneal nerve when compared contralaterally. Ultrasound of fibular and tarsal tunnels were unremarkable, however, an enlarged, hypoechoic structure was identified peri-neurally to a terminal branch adjacent to the medial calcaneal tuberosity.
Discussions: Typically, heel pain is secondary to degenerative structural changes (plantar fasciitis, calcaneal osteophytes, and stress fractures). Pathognomonically patients experience pain with ambulation after prolonged non-weightbearing. Neuropathic heel pain is convoluted, the pain referral differs by involving the medial heel and arch predominantly, not dependent on weight bearing, and less responsive to standard treatments. Differential includes tarsal tunnel syndrome and inferior calcaneal nerve entrapment (Baxter’s neuritis). However, we overlook potential entrapment of other distal branches of posterior tibial nerve, including medial calcaneal nerve. In this case, use of EDx in combination with sonographic studies demonstrated an unlikely culprit, compression neuropathy of the medial calcaneal nerve secondary to a neuroma. Patient returned to neurosurgical follow-up after restarting alpha lipoic acid, Lyrica, and custom orthotics which improved her symptoms. Ultimately, the neurosurgeon continued conservative management.
Conclusions:
Diagnosing neuropathic heel pain is challenging. While the inferior calcaneal nerve is a notorious source, other terminal branches of the posterior tibial nerve are overlooked. Though less common, the medial calcaneal nerve should also be considered with EDx and sonographic evaluation.
