Abstract:
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Purpose: To describe the potential use of high-frequency US for evaluation of tibial nerve.
Methods and Materials: The anatomy of the tibial nerve and perineural structures was evaluated at the tarsal tunnel on 2 cadaveric ankles and correlated with the US images obtained in 10 healthy subjects. Then, 14 consecutive patients with numbness or pain in the foot and ankle and paresthesias in the sole of the foot suggesting dysfunction of the tibial nerve were evaluated using 12-5MHz linear transducers. All patients had electromyographic studies and underwent MR imaging on a 1.5T unit. Seven were operated and followed-up with US.
Results: One-to-one comparison between cadaveric specimens and US scans showed the tibial nerve and its divisional branches (medial plantar nerve, lateral plantar nerve, calcanear nerve) can be reliably identified with US throughout the tarsal tunnel. US allowed detection of a wide spectrum of nerve abnormalities. Lesions included: tenosynovitis of the flexor hallucis longus tendon (n=2); ganglia related to the subtalar joint (n=3); lipoma (n=1); venous engorgement of the posterior tibial veins (n=1); anomalous muscle (flexor digitorum accessorius longus) (n=1); schwannomas (n=2) focal abnormalities following trauma (n=4), including open wound from knife (n=1), foreign body (n=1), closed traction injury associated with fracture dislocation (n=1), and prominent bony spur at the posteromedial talus (n=1). Of these lesions, all but one involved the main trunk of the tibial nerve in the retromalleolar area and 5 were palpable. US gave useful information on level of compression, nature of constricting findings and continuity of the nerve.
Conclusion: US is promising for evaluating the tibial nerve. It can identify and characterize a variety of nerve abnormalities. By providing unique information on the entire course of the tibial nerve, US has potential for major impact on treatment planning.
Questions about this event email: lorenzobacigalupo@yahoo.com
Bacigalupo MD, L,
High-Frequency Ultrasound of Tibial Nerve Entrapment at the Tarsal Tunnel. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3107475.html
