Locating tibial nerve bifurcation in tarsal tunnel syndrome
Tarsal tunnel syndrome is a disorder that affects the tibial nerve or its branches: the medial plantar nerve, the lateral plantar nerve, the medial calcaneal nerve, the motor branch of the abductor muscle to the fifth toe, and the first calcaneal branch.
This peripheral neuropathy is considered less common than carpal tunnel syndrome but is much more complicated to diagnose, so its true incidence may be underestimated. Diagnostic imaging can help identify the site of compression.
In this study, 12 cadaveric specimens were used. Musculoskeletal ultrasound (US) and dissection were performed, and correlation between the 2 methods and distribution and anatomic variability of branches of the tibial nerve were determined.
It was found that, regarding the location of the bifurcation of the tibial nerve, with US a 100% agreement was obtained between US and dissection. Moreover, 91% of tibial nerve bifurcations were in the areas corresponding to types IA and IB: 1 cm distal and 1 cm proximal to the malleolar-calcaneal axial line, respectively. The US topography and the anatomic dissection were completely correlated.
This study provides information for establishing a working method in the surgical setting, as the surgeon can perform a study and design the surgery with US support, observing the patient’s anatomy and anatomic variations before proceeding to surgical dissection, which could prevent intraoperative complications.
> From: Iborra, J Ultrasound Med (2017) (Epub ahead of print). All rights reserved to the American Institute of Ultrasound in Medicine. Click here for the online summary.