Standing ovariectomy in mares using a transvaginal natural orifice transluminal endoscopic surgery (NOTES®) approach.

Objective: To develop and assess the feasibility of standing transvaginal Natural Orifice Transluminal Endoscopic Surgery (NOTES®) ovariectomy in the mare.

Study Design: Descriptive study.

Animals: Mares (n=10).

Methods: The technique was developed in 6 mares and then evaluated in a short-term study in 4 mares. Abdominal access was developed using controlled access vaginal cannula placement under endoscopic guidance. With viewing provided by a flexible endoscope, hemostasis, and transection of ovarian pedicles was performed using a customized bipolar vessel-sealing device. The ovaries were retrieved and the colpotomy was sutured. Surgical time, intra-, and postoperative complications were recorded. Necropsy was performed immediately after surgery in 6 mares and 15 days after surgery in 4 mares to assess short-term complications.

Results: After the instruments and techniques were developed, transvaginal NOTES® ovariectomy was successfully performed. Analgesia during the procedure was adequate in all cases. The visual field provided by the endoscope was acceptable. The customized 60 cm vessel-sealing device provided good hemostasis and a comfortable working length. Intraoperative complications included difficult viewing that prolonged operative time and inability to remove the second ovary in 1 mare. Postoperative recovery was excellent. Postmortem findings of 1 true positive microbial culture, elevated cell counts in abdominal fluid, and adhesion formation raise questions that must be addressed in future studies.

Conclusion: Using specialized instruments, transvaginal NOTES® ovariectomy is technically feasible in mares.