Ideal intraspinal implantation site for the repair of ventral root avulsion after brachial plexus injury in humans. A preliminary anatomical study.

The advances made to date in root reimplantation for avulsion of the brachial plexus are modest considering that there are only reports from ten patients in the literature. However, the results are promising and should be applauded. The problem with reimplantation, in addition to the difficult surgical exposure, is to determine the ideal intraspinal implantation site for the graft. Given the non-permissive substrate properties of the CNS white matter, the outcome of grafts elsewhere in the spinal cord need to be evaluated. An inappropriate implantation site might explain the still modest recovery in this challenging group of patients. Consequently the microscopic anatomy of the cervical spinal cord segments C5 to T1 was studied. The aims were to 1--determine the relationships between the ventral gray horn and the ventrolateral sulcus of the spinal cord, and 2--analyse the location and course of the motoneuron fibres passing through the white matter to reach the ventral root. On the basis of the present findings it is proposed that reimplantation of nerve grafts or rootlets should be performed directly through the ventral root exit zone in contact with the ventromedial region of the ventral gray horn at a depth of 2 mm, rather than into the white matter of the lateral aspect of the cord. Initially we used a posterior approach with total facetectomies. An anterior approach is now evaluated for current use.