[Regeneration of the cauda equina after transection and end-to-end anastomosis in the dog].

This study was designed to test surgical techniques for reconstruction of an injured cauda equina. After transection of the intradural lumbar nerve root, end-to-end anastomosis was performed under surgical microscope in the dog. To preserve accurate adaptation of the transected nerve root, the root sheath and the funiculi were carefully sutured with a minimal number of stitches. Regenerated axons in the ventral root appeared distal from the suture at five weeks postoperatively, whereas those in the dorsal root appeared at seven weeks after anastomosis. The histogram and regrowth rate of the ventral root showed regenerative processes similar to those of peripheral nerves, though a little slower. The fact that an evoked potential from the sutured ventral root was recordable after stimulation of the sciatic nerve indicated restoration of nerve conduction. Although further experimental studies are required to develop adequate surgical techniques, microsurgical anastomosis of the transected cauda equina is potentially applicable for appropriate clinical cases of a cauda equina injury.