End-to-side anastomosis of transected nerves to prevent neuroma formation

Neuroma can be painful and physically and psychologically disabling. Among the many methods of treatment available, one of the more successful is cent rocentral nerve union with an autologous graft. However, it cannot be used in small nerves that lack two fascicles, This study evaluated neuroma preve ntion in an end-to-side anastomosis, a new technique applicable to all nerv es. The lateral branch of the right sciatic nerve in 20 rats was transected at the midthigh level. The proximal segment was looped back to the main ne rve and an end-to-side epineural anastomosis was performed. The lateral bra nch of the left sciatic nerve was transected to serve as a control, and the proximal nerve stump was closed by interrupted epineural sutures. The anim als were sacrificed 12 weeks after the operation. Histologic analysis of sp ecimens from the 12 controls showed neuroma formation. Specimens from 12 si de-to-end anastomoses contained regenerated nerve tissues and formed smalle r masses compared with that of the controls. The regenerated tissues at the anastomoses were orientated more orderly than were tissues from the contro ls in 75% of cases. The differences were statistically significant. Electro n microscopic study on specimens from the remaining eight controls showed t he presence of abundant large abnormal myelinated fibers (10-15 mu m) with thick irregular myelin sheaths scattered among smaller myelinated fibers (2 -10 mu m) that had thin myelin sheaths, In the remaining eight end-to-side anastomoses, large abnormal myelinated fibers were absent. The myelinated f ibers were 2 to 10 mu m in diameters and had a normal appearance with thin myelin sheaths. End-to-side anastomosis formed a smaller mass of regenerate d nerve tissues. Ultrastructurally they were formed better and orientated m ore orderly resembling normal nerve.