An Iatrogenic Cause of Proximal Tibial Mononeuropathy Resulting in Undiagnosed Foot Pain
Austin Priaulx1, John Evans2
1Philadelphia College of Osteopathic Medicine, 2Mayo Clinic
Objective:
N/A
Background:
Tibial neuropathies are a relatively uncommon cause of lower extremity mononeuropathies. Unlike distal tibial nerve injuries, proximal tibial nerve palsies are less commonly associated with compression, and more often associated with trauma. This is a case report of a proximal tibial nerve injury secondary to a regional anesthesia procedure.
Design/Methods:
N/A
Results:
A 43 year old man presented to an outpatient PM&R clinic as a forth opinion for persistent left foot pain after surgical removal of a broken sewing needle. Eighteen months prior, the patient had stepped on a sewing needle resulting in a fragment to be lodged in the soft tissue of the left heel. The patient underwent a tibial nerve block and the fragment was surgically removed. After the surgery, the heel pain resolved, but the patient developed burning pain in the plantar aspect of their left forefoot. The patient saw multiple local providers, including a neurologist who performed an EMG that showed a chronic, inactive medial plantar neuropathy. Examination in PM&R clinic demonstrated a normal neurological examination aside from atrophy of the left gastrocnemius and foot intrinsic muscles, and a reduced achilles reflex. The patient subsequently underwent a second EMG that showed a chronic left tibial mononeuropathy proximal to the innervation of the medial head of the gastrocnemius
Conclusions:
Proximal tibial mononeuropathies are rare due to the nerve being located deep in the popliteal fossa and well protected. While distal tibial neuropathies are more common, they are not associated with changes to the gastrocnemius muscle. Regional anesthesia has the risk of injuring the nerve being anesthetized, and can be an iatrogenic cause of pain and neurologic impairment.  Appropriate localization of tibial nerve lesions is important to direct treatment in cases that are refractory to treatment.
10.1212/WNL.0000000000203216