The use of coaxially aligned freeze-thawed skeletal muscle autografts in the repair of the cauda equina--in the sheep.

The aim was to develop a model for study of nerve regeneration in nerve roots above the level of the dorsal root ganglion and to investigate the use of freeze-thawed muscle autografts for repair of nerve roots at this level. Four adult sheep were used for the experiment. A laminectomy was performed at the lumbosacral junction and the S2 root identified. Both the dorsal and ventral S2 roots were divided unilaterally within the dura and a freeze-thawed muscle graft was inserted into the nerve gap. When assessed at 6 months an action potential was recordable from the ventral root in one sheep. Histological examination of the nerve roots showed evidence of regeneration across the graft in the ventral roots of all the sheep and the dorsal roots of some. This preliminary work indicates a capacity for regeneration of the cauda equina and that freeze-thawed muscle can support this. It provides a useful model for further study of nerve root repair.