Transdiscal C6-C7 contralateral C7 nerve root transfer in the surgical repair of brachial plexus avulsion injuries

Repair of complete brachial plexus avulsion injuries may require contralateral C-7 nerve root transfer. The available techniques might allow direct neuroraphy in about 50 % of cases but the others require interposing nerve grafts or humeral shaft shortening. We aimed to see if transdiscal C-6-C-7 contralateral C-7 nerve root transfer is technically feasible and if it allows direct coaptation with the contralateral nerve roots in 100 % of cases. In ten fresh-frozen adult cadavers, the C-7 nerve root was sectioned just before it connects with other brachial plexus branches and re-routed though the C-6-C-7 disc space to the contralateral side. A complete C-6-C-7 discectomy was performed and the disc space kept open with the aid of an autologous iliac crest bone graft. Transdiscal C-6-C-7 contralateral C-7 nerve root transfer is technically feasible. In our cadavers, it provided 5.3 +/- 1.2 SDcm of extra length that allowed direct coaptation with the contralateral nerve roots, mainly C-8 and T-1. Transdiscal C-6-C-7 contralateral C-7 nerve root transfer is technically feasible. In our dissections it lengthens the available C-7 nerve root stump by 5.3 +/- 1.2SDcm. The increase was 4 cm versus the retropharyngeal route making direct coaptation with the contralateral C-8 and T-1 nerve roots possible.