Laser nerve welding

Microsurgial suture (Conventional microsurgical suture repair, CMSR) is the most commonly used method for anastomosis of severed peripheral nerves. Functional recovery after this type of repair is often inadequate, however, even though the peripheral nervous system has a remarkable ability to regenerate adequate sizes and numbers of axons. The most significant problems with microsuture repair are inherent in the technique: (1) surgery traumatizes the nerve by repeated introduction of a needle; (2) suture material at the anastomotic site presents a focus for scar and neuroma formation that may impede the growth of regenerating axons from the proximal segment into the proper distal segment endoneurial tubes and, ultimately, the neuromuscular junction; (3) microsurgical repair inevitably leaves small gaps that allow entry of fibroblasts and other scar tissue forming cells, permit regenerating axons to escape into an improper extraneural space, and promote loss of neurotrophic hormones that may be secreted locally to aid in the conduction of regenerating axons to their proper target; and (4) microsurgery is time-consuming and may be difficult to perform in restricted areas, particularly when supportive epineurial material is scarce. Also, especially in the head and neck region, there are often areas in which poor exposure or difficult surgical access precludes the placement of microsutures in nerve repair (Korff et al., 1992; Eppley et al., 1989; Huang et al., 1992). A major focus of nerve repair research has been the development of procedures with which to avoid or minimize the use of sutures and prevent fibrous ingrowth at the repair site (Menovsky & Beek, 2001; Maragh et al., 1988). Several sutureless methods have been developed, although none of them has been demonstrated to be consistently superior to sutures. Most importantly, sutureless methods must fulfill several criteria to have an advantage over suture repair. First, the procedure must result in a sufficient acute tensile strength. Second, it must not compress the nerve and must not involve increased severity of trauma compared with sutures. Third, the early and late tissue reaction of the nerve must be kept to a minimum and the axonal regeneration must not be impaired (Menovsky & Beek, 2001). The laser was introduced in 1960s and is now widely used in medicine and surgery for the cutting, coagulation, and vaporization of various tissues. At low powers, thermal lasers, such as CO2, argon, and YAG, can be used to ‘weld’ tissue together by local protein coagulation. This property of the laser has been applied to nerve anastomosis as well as other tubular structures, such as vessel, bowl (Huang et al., 1992; Okada et al.,1987; Neblett 2