A novel extradural nerve transfer technique by coaptation of C4 to C5 and C7 to C6 for treating isolated upper trunk avulsion of the brachial plexus.

The study aimed to demonstrate the feasibility of an extradural nerve anastomosis technique for the restoration of a C5 and C6 avulsion of the brachial plexus. Nine fresh frozen human cadavers were used. The diameters, sizes, and locations of the extradural spinal nerve roots were observed. The lengths of the extradural spinal nerve roots and the distance between the neighboring nerve root outlets were measured and compared in the cervical segments. In the spinal canal, the ventral and dorsal roots were separated by the dura and arachnoid. The ventral and dorsal roots of C7 had sufficient lengths to anastomose those of C6. The ventral and dorsal of C4 had enough length to be transferred to those of C5, respectively. The feasibility of this extradural nerve anastomosis technique for restoring C5 and C6 avulsion of the brachial plexus in human cadavers was demonstrated in our anatomical study.