EVALUATION OF TISSUE ADHESIVE TO CONTAIN AXONAL REGENERATION IN HORSES

Bilateral palmar and plantar digital neurectomies were completed in 10 horses (a total of 80 neurectomies) using one of three methods: (1) s imple transection (guillotine method): (2) epineural capping; (3) n-bu tyl cyanoacrylate injected into the epineural sheath to act as a nerve sealant. Horses were regularly evaluated clinically for tenderness in and around the surgical site, as well as skin sensation at the corona ry band in the heel region, during the 1 a-week course of the study. N one of the surgical sites exhibited any signs of drainage or infection . Horses were then euthanatized, the nerve stumps were dissected from surrounding tissues, and the length and width of the tissue mass that had formed on the end of the nerve was recorded. Longitudinal and tran sverse sections of the nerve endings were examined histologically for numbers of proliferating axon sprouts (neuroma formation); whether the axons had penetrated the epineurium: degree of Schwann cell prolifera tion; degree of chronic inflammation; extent of foreign body reaction; extent of retrograde degeneration of the nerve bundles; and amount of fibrovascular proliferation. The proportion of legs exhibiting tender ness or heel sensation did not differ significantly between the three different treatments at any of the six different times they were exami ned. There was no difference between the three treatments in the lengt h or width of the fibrous tissue scar on the ends of the nerves or in the number of sprouting axons from the ends of the nerves. Of 80 nerve s examined, only two nerves were not confined to the epineurium. Both these nerves had been treated by simple transection. Statistically the re was more chronic inflammation and foreign body reaction in the acry lic treated nerves, but no difference in Schwann cell proliferation or retrograde degeneration between the three treatments. There was sligh tly less fibrovascular proliferation in the transected nerves than in those subjected to epineural capping or acrylic, but the difference wa s not statistically significant. The use of the tissue adhesive n-buty l cyanoacrylate to prevent the continuous growth of axons after digita l neurectomy seems to offer little advantage over more traditional met hods of neurectomy. (C)Copyright 1995 by The American College of Veter inary Surgeons