Anatomic and Ultrasonic Study Based on Selective Tibial Neurotomy.

BACKGROUND: Selective tibial neurotomy (STN) was considered as an effective procedure for the treatment of spastic feet. It is also widely used for treating obese calves in some Asian countries. This study aimed to provide morphologic measurement data and theoretical support for the operation and intraoperative localization.

METHODS: Fifty lower legs from 20 embalmed cadavers and 5 fresh corpses were dissected to observe and record the relationship of 4 branches of the tibial nerve, as well as the length, width, and thickness of the triceps surae. An ultrasonic transducer was also used to measure the thickness of muscles of 50 volunteers and acquire the ultrasonic image of muscles and nerve branches.

RESULTS: Anatomic results showed that the tibial nerve gave off 4 branches in a proximal to distal direction: the medial sural cutaneous nerve, the motor branches innervating the medial and lateral gastrocnemius, and the motor branch innervating the soleus. These nerve branches had 8 patterns of origin. A significant finding was that the nerve innervating the soleus consisted of 2 branches. Ultrasonic measurement results showed that the thickness of the gastrocnemius and the soleus were positively related to the circumference of the calf.

CONCLUSIONS: The calf circumference was positively related to the thickness of the soleus and the gastrocnemius. Diverging patterns of tibial nerve branches were multiple, and caution should be used to prevent damaging other branches. Tibial nerve, branches, and diverging sites could be seen clearly in the ultrasonic image. A preoperational ultrasonic examination is recommended.