✓ Studies on the peripheral nerves in rats and other species have helped in the development of laser-assisted nerve anastomosis (LANA), but offer little in evaluating the efficacy of this technique in primates. The authors present a study of LANA in the peripheral nerves of rhesus monkeys. Twelve adult rhesus monkeys underwent bilateral resection of a portion of the peroneal nerve followed by placement of autogenous sural nerve interposition fascicular grafts. The grafts were completed with conventional microsurgical suture technique on one side and with LANA on the other. At 5, 8, 10, and 12 months, the grafted nerves were evaluated for continuity, nerve conduction, and histology (both light and electron microscopy). No significant difference in continuity, conduction velocity, nerve degeneration, nerve regeneration, axon fiber number, or axon fiber density was found in any animal between grafts performed by conventional microsuture and LANA grafts. There was no difference in distal or proximal myelinated fiber density between the LANA grafts and the conventional microsuture grafts. It was concluded that LANA is as effective as microsurgical suture nerve anastomosis in a primate model of nerve repair and grafting.
Julian E. Bailes, Jeffrey W. Cozzens, Alan R. Hudson, David G. Kline, Ivan Ciric, Peter Gianaris, Lawrence P. Bernstein and Daniel Hunter
Alan R. Hudson, Daniel Hunter, David G. Kline and Bert R. Bratton
✓ Biopsies of sutured and grafted primate peripheral nerves were examined by light and electron microscopy after the final set of electrical measurements had been recorded. Inspection of all proximal stumps showed the expected regenerative activity which was not affected by the nature of the nerve repair. Transverse sections through the epineurial, interfascicular, and graft suture lines showed a similar pattern in all animals and at this site nerves sutured by epineurial technique could only be distinguished from those sutured by fascicular technique by loci of the non-absorbable suture. Fascicular repairs, whether done fascicle-to-fascicle or with interposition of grafts, had a more lengthy neuroma than did the epineurial repairs. Maintenance of fascicular architecture through the course of the grafts was variable. Fascicular structure was frequently absent in the central graft segments and in segments close to the second suture site. The method of repair used more proximally could not be distinguished by evaluation of distal stump segments. Measurements of myelinated fiber size made of distal stump axons revealed no statistical difference between the methods of repair.