Distraction Neurogenesis in the Upper and Lower Extremities

Management of peripheral nerve injury with a segmental loss of nerve tissue, caused either by trauma or tumor excision, is a difficult reconstructive problem for many surgeons. The current standard clinical treatment for reconstruction of large peripheral nerve defects is autogenous nerve graft; absorbable and non-absorbable conduits are also used with variable success. From another viewpoint, the widely accepted Ilizarov procedure used for limb lengthening not only stretches the callused bone; it also causes lengthening of the soft tissue of the extremity and the nerve, without functional loss of neural tissue. In the authors' procedure, when the nerve defect is not excessive and the nerve passes across a joint, a microsurgical end-to- end-repair is performed after the joint is placed in position. Then, a special splint designed for lengthening purposes is used, and a gradual nerve-lengthening process is accomplished.

From March 1, 2003 to December 30, 2004, all patients who came to Hazrat Fatemeh Hospital in Tehran for nerve reconstruction, with the nerve defect less than requiring grafting and with the nerve passing across a joint, were repaired by maximal positioning of the joint. The nerve with a tolerable tension was repaired and nerve elongation was commenced after 7 days using a special splint which had an adjustable articulation joint.

Thirteen patients were treated with this procedure. Eight of them had nerve interruption in the wrist, four in the elbow, and one of them in the distal thigh. The length of the nerve varied from 3 to 8.5 cm. The ulnar nerve was elongated in 7 patients, the median nerve in 5 patients, and the sciatic nerve in one patient. Duration of elongation was 4 to 8 weeks. All patients tolerated this procedure very well, and the results were good to excellent.

An end-to-end nerve repair is the best method for peripheral nerve injury. In cases with paucity of nerve length, reconstruction by this method is not possible. In those instances, nerve grafting was undertaken. The results were poor, and morbidity at the donor area was a further complication. In the extremities, especially at the knee and elbow, the authors repair the nerve defect by fixing the joint and carrying out an end-to end-repair, and then lengthening the nerve gradually. In this study with this method, the nerve can be elongated up to 8.5 cm.