Oophorectomy by natural orifice transluminal endoscopic surgery: feasibility study in dogs

Background: Natural orifice transluminal endoscopic surgery (NOTES) represents a potentially less-invasive alternative to conventional or laparoscopic surgery. Objective: Our purpose was to develop a canine oophorectomy model for prospective evaluation of intraoperative complications, surgical stress, and postoperative pain and recovery with NOTES. Design: Feasibility study. Setting: Academic preclinical research. Patients: Ten healthy female dogs. Interventions: NOTES procedures were performed through gastric access with an electrocautery snare to resect and retrieve the ovaries. The gastrotomy was closed with prototype T-fasteners. Main Outcome Measurements: Operative time; complications; postoperative pain scores, and nociceptive threshold; surgical stress markers (interleukin-6 [IL-6], C-reactive protein); systemic stress parameters (cortisol, glucose); necropsy evaluation at 10 to 14 days. Results: The mean operative time was 154 minutes (SD ± 58 minutes) and no animals died as a result of complications from the procedure. The primary difficulty was incomplete ovarian excision and conversion to an open procedure in 1 dog. Serum glucose concentrations increased after surgery and remained elevated for at least 36 hours. The serum cortisol concentration was transiently increased from baseline at 2 hours after surgery. The serum IL-6 concentration peaked at 2 hours after surgery and returned to the baseline value by 18 hours. The serum C-reactive protein concentration increased significantly from baseline, peaked at 12 hours after surgery, and then slowly declined toward baseline but remained elevated at 72 hours after surgery. Nociceptive threshold measurements indicated increased sensitivity to pain for 2 to 24 hours after surgery. At necropsy, surgical sites were healing uneventfully with no significant damage to surrounding organs, no significant growth on bacterial cultures, and no evidence of peritonitis. Limitations: Small number of animals, single center. Conclusions: The NOTES approach to oophorectomy in dogs appears to be a reasonable alternative to traditional surgery. Attention must be paid to ensure complete excision of the ovaries.