An Investigation of the Potential for Laser Nerve Welding.

Suture repair of a severed peripheral nerve is cumbersome, presents a focus for infection and neuroma formation, and does not always produce adequate stump alignment. An alternative form of repair is laser nerve welding which is attractive because it does not introduce foreign material into the anastomotic site, it forms a circumferential seal, and it can be performed in difficult to reach areas. Laser repair has not been widely accepted both because the effect of laser irradiation on intact nerves is not well documented, and the anastomotic strength of the weld has been inferior to suture repair. In the first part of the present study, rat sciatic nerves were exposed and irradiated with increasing intensities from a Sharplan C02 and a KTP laser to document nerve damage as recorded by decreases in the peak compound action potential (CAP). A new technique of laser repair (S-Q weld) was then developed which involved harvesting subcutaneous tissue from the adjacent dermis, wrapping it around the two opposed nerve stumps, and lasering it to the epineurium to effect a weld. The strength of the S-Q weld (6.1 grams) was considerably greater than that produced by laser welding alone. The third phase of the study compared regeneration at two months in severed rat sciatic nerves repaired by either microsuture or S-Q weld. Analysis of the CAP values indicated that the number of regenerating fibers following laser repair was greater than that following suture repair, although a significant difference could not be demonstrated. The rate of nerve dehiscence in the laser repair was unacceptably high, but the observed advantages of the technique indicate a need for further investigation.
Presented at Washington, DC on 27 Sep 88.