Repair of the rectovaginal fistula in the mare – a new surgical approach

Abstract

SummaryIt was the aim of the study to develop a new surgical method to repair the so called rectovestibulum fistula (RVF) in the horse: In this context it was intended to combine and take up advantageous aspects of methods already established in plastic surgery for this traumatically caused defect. Known disadvantages of the different methods such as surgical transfer of the fistula to a third degree perineal laceration, difficult practicability and high incidence of recidives were minimized. The primary aspect of the new surgical method is the surgical transfer and inclusion of a second degree perineal laceration by which main parts of the perineal body and shincter ani in toto are maintained. After training phases for general feasability of the new procedure surgery was simulated on isolated pelvic organs (n = 15) and in straight before sacrified animals (n= 8) the operations were performed on 6 experimental and 4 client mares. The healing process until the removal of the sutures was without any clinical complications. On the average the clinical healing of the fistula operated was completed after two weeks. Complications such as intestinal constipation, tenesmus, excessive inflammatory reactions or general worsening of well-being of the mares did not show up in any case. In 8 of 10 cases the fistula was completely closed after a first surgery. In two (experimental mares) of the 10 cases there was a recidive of a now considerable smaller fistula which was in one mare closed and healed after a second surgery. In one of these two mares a second recidive occured demanding a third surgery session. Ultrasound measurements revealed a remarkable increase of the interrectovestibular tissue. After euthanasia of the experimental mares pathologicalanatomical and histological examinations of the rectal bottom and vestibulum roof within the area of the surgical site revealed similar results in all samples prooving a definite healing with scars which has to be regarded as stable. As a conclusion it can be stated that the new established plastic surgery of RVF can be recommended for practical use as it fulfilled the main aims of (1) durable and stable surgical closure of the RVF, (2) maintenance of integrity of the closing function of the anal sphincter, and (3) reliable external genital closure. Keywords:mare, rectovaginal fistula, plastic surgery, perineal integrity

A Vaginal Mucosal Pedicle Flap Technique for Repair of Rectovaginal Fistula in Mares

“…Other principles that are critical to successful outcome are appropriate fecal consistency during the perioperative and early healing period, adequate debridement of the RVF, and secure closure of the defect to avoid fecal contamination of the wound tissues and vagina. There is general agreement that repair of RVF should respect the integrity of the anal sphincter and perineal body to prevent contamination of the urogenital tract 2 . This principle is observed with our technique and with adequate perineal relaxation from epidural anesthesia and retraction of the labia, observation of, and access to, the operative field was acceptable.…”

“…RECTOVAGINAL FISTULAE (RVF) are a challenging surgical problem in mares because of less than optimal operative visibility, bacterial contamination, and continued rectal peristalsis. Various techniques for repair of RVF have been reported 1–3 . Dehiscence is a relatively common problem that results from a combination of factors including the continued stress of peristalsis on the healing wound and in primary appositional techniques, tension on the suture line 4–7 …”

A modified surgical technique for repairing third-degree perineal lacerations in mares

“…Epidural and infiltration anaesthesia of the vulva and the perivestibular and perineal region maintained the mare in a standing position and achieved sufficient immobilisation (Trotter, 1992;Le Blanc, 1999;Klug et al, 2001). Vestibular shelves are sutured reciprocally by different sutures and the suture line of the rectovestibular septum is parallel to the median line in the method of Aanes and Goetze method (Turner and McIlwraith, 1989;Trotter, 1992;Le Blanc, 1999;Adams and Fessler, 2000).…”

“…The method of Aanes and its modifications are also commonly employed (Turner and McIlwraith, 1989). In these methods, surgery is two staged and the affected tissues are sutured in such a way that the suture line is parallel to the median line (McIlwraith and Robertson, 1986;Arthur et al, 1989;Le Blanc, 1999;Adams and Fessler, 2000;Klug et al, 2001).…”

Rectovaginal Fistula Repair

“…7 The Klug technique provides good visualization, a durable and stable closure, and good first-time healing success rate without disrupting the integrity of the anal sphincter. Repairing a large fistula using this technique should be attempted with caution.…”