Laser-activated protein solder for peripheral nerve repair

A 100 pm core optical fibre-coupled 75 mW diode laser operating at a wavelength of 800 nm has been used in conjunction with a protein solder to stripe weld severed rat tibia! nerves, reducing the long operating time required for microsurgical nerve repair. Welding is produced by selective laser denaturation of the albumin based solder which contains the dye indocyanine green. Operating time for laser soldering was 10 ± 5 mm. (n20) compared to 23 ± 9 mm. (n10) for microsuturing. The laser solder technique resulted in patent welds with a tensile strength of 15 ± 5 g, while microsutured nerves had a tensile strength of 40 ± 10 g. Histopathology of the laser soldered nerves, conducted immediately after surgery, displayed solder adhesion to the outer membrane with minimal damage to the inner axons of the nerves. An in vivo study is under way comparing laser solder repaired tibial nerves to conventional microsuture repair. At the time of submission 15 laser soldered nerves and 7 sutured nerves were characterised at 3 months and showed successful regeneration with compound muscle action potentials of 27 ± 8 mV and 29 ± 8 mV respectively. A faster, less damaging and long lasting laser based anastomotic technique is presented.