Hybrid natural orifice transluminal endoscopy surgery (NOTES) to perform bilateral ovariectomy in mares.

Objectives: To combine laparoscopic techniques with natural orifice transluminal endoscopic surgery (hybrid NOTES) to minimize number and enlargement of paralumbar laparoscopic portals for bilateral ovariectomy in standing, sedated mares.

Study design: Case series.

Animals: Six horses.

Materials and methods: Six mares with palpably normal ovaries were restrained in stocks, sedated, and had caudal epidural anesthesia performed. A 7.5 MHz ultrasound probe was used transvaginally to select placement of vaginotomy. An attempt was made to remove both ovaries with 70 cm esophageal forceps through the vaginotomy, while visualized and transected via ipsilateral paralumbar fossa laparoscopic portals. Surgical time, intraoperative, and postoperative complications were recorded. Vaginoscopy was performed at days 0, 3, 7, and 14 postoperatively. After 14 days, mares were euthanized and necropsied.

Results: Hybrid NOTES allowed successful bilateral ovariectomy in all six mares, with a mean surgical time of 70 ± 25 min. In two mares, one ovary was dislodged from the forceps during vaginotomy extraction. Abdominal retrieval of the ovary was successful with reapplication of forceps or a surgeon's hand via vaginotomy. At necropsy, five mares had no adhesions within the abdominal cavity or at the vaginotomy site. One mare in which hand retrieval of the ovary was necessary, developed an adhesion between the bladder and the vaginotomy.

Conclusions: This technique appears to offer a safe alternative for bilateral ovariectomy with minimal postoperative complications.

Clinical significance: Decreased number and size of paralumbar laparoscopic incisions could decrease complications associated with exteriorization of ovaries through the flank.