Proximal motor branches from the tibial nerve as direct donors to restore function of the deep fibular nerve for treatment of high sciatic nerve injuries: a cadaveric feasibility study.

OBJECTIVE: The results of surgical repair of the fibular division of the sciatic nerve have been considered unsatisfactory, especially if grafts are necessary to reconstruct the nerve. To consider the clinical application of the concept of distal nerve transfer for the treatment of high sciatic nerve injuries, this study aimed to determine detailed anatomic data about the possible donor branches from the tibial nerve that are available for reinnervation of the deep fibular nerve at the level of the popliteal fossa.

METHODS: An anatomic study was performed that included the dissection of the popliteal fossa in 12 lower limbs of 6 formalin-fixed adult cadavers. It focused on the detailed anatomy of the tibial nerve and its branches at the level of the proximal leg as well as the anatomy of the common fibular nerve and its largest divisions at the level of the neck of the fibula, i.e., the deep and superficial fibular nerves.

RESULTS: The branches of the tibial nerve destined to the lateral and medial head of the gastrocnemius had a mean length of 43 mm and 35 mm, respectively. The branch to the posterior soleus muscle had a mean length of 65 mm. Intraneural dissection of the common fibular nerve, isolating its deep and superficial fibular divisions, was possible to a proximal mean distance of 71 mm. A tensionless direct suture to the deep fibular nerve was made possible by using the nerve to the lateral head of the gastrocnemius and the nerve to the posterior soleus muscle in all specimens. Direct suture of the nerve to the medial head of the gastrocnemius was possible in all cases except 1.

CONCLUSION: The nerve to the lateral and medial heads of the gastrocnemius and the nerve to the posterior soleus muscle can be used as donors to restore function of the deep fibular nerve in cases of high sciatic nerve injury. However, proximal intraneural dissection of the deep fibular division of the common fibular nerve must also be performed. We recommend that the nerve to the posterior soleus muscle should be the first choice for a donor in the proposed transfer.