Comparison of microscopic and macroscopic repair in rabbit urethral fistulae.

Two fistulae were created in each of 26 adult male New Zealand rabbits. In six, no closure was carried out. In 20 rabbits subsequent closure was carried out using, alternately, a macroscopic and microscopic technique. We were then able to evaluate a total of 26 repaired fistulae using several parameters. Patency of the fistulae was present after 3 months in all six rabbits in which no closure was carried out. Comparison of the two techniques showed nine recurrences or persistent fistulae in the ten repaired by standard macroscopic techniques, and one fistulae still present after closure of 16 fistulae using microsurgical principles. This preliminary study emphasizes the potential improvement in urethral fistula repair using the operating microscope. Direct transfer into the clinical setting is underway with the use of techniques used in the Microsurgical Laboratory at the University of British Columbia.