Comparison of Pain and Postoperative Stress in Dogs Undergoing Natural Orifice Translumenal Endoscopic Surgery (NOTES)®, Laparoscopic, or Open Bilateral Oophorectomy

Abstract

Background: Few studies are available to compare the potential benefits of NOTES to traditional surgery. Objective: Compare intra-operative complications, markers of surgical stress, and post-operative pain and recovery with NOTES versus laparoscopic and open abdominal oophorectomy. Design: Prospective study; Setting: Academic center; Subjects: 30 healthy female dogs underwent bilateral oophorectomy procedures performed via NOTES (n=10), laparoscopic (n=10) and traditional open (n=10) approaches. Main outcome measurements: Operative time; surgical and postoperative complications; postoperative pain scores and nociceptive threshold; surgical stress markers (IL-6, C-reactive protein); systemic stress parameters (cortisol, glucose); 3 day clinical observation. Results: Mean operative times were 80 (STD ±30), 44 (STD ±9), and 37 (STD ±12) minutes for the NOTES, laparoscopic and open procedures, respectively. All of the ovaries were completely excised and all dogs survived. One of the dogs in the NOTES group was excluded from postoperative monitoring due to temperament. Except for postoperative hypothermia, all physiologic parameters remained within expected limits in all animals. Serum glucose concentrations increased (P<0.05) after surgery and remained elevated for at least 36 hours with no differences between groups. Serum cortisol concentrations increased (P<0.05) from baseline at 2 hours after surgery in the laparoscopic group and at 2 and 4 hours after surgery in the open and NOTES groups. Serum IL-6 concentration was increased at 2, 6, and 12 hours compared to baseline in the NOTES group, but not in the open or laparoscopic groups, with no statistically significant differences between groups. Serum C-reactive protein concentration was significantly elevated in the NOTES animals from 6 to 72 hours compared to baseline and in the laparoscopic group at 12 hours. The mean pain score and the nociceptive threshold measurements revealed that the NOTES group demonstrated less evidence of pain than either the laparoscopic or open groups. Conclusions: NOTES oophorectomy in dogs appears to be as safe but presents a steep learning curve, requiring more time to perform than traditional surgery. Despite relative elevations of surgical stress markers, NOTES animals appeared less painful and experienced an uneventful postoperative recovery. Therefore NOTES may represent an alternative to open or laparoscopic surgery in these animals. Further studies are warranted. ∗This study was conducted in compliance with the Purdue Animal Care and Use Committee, Purdue University, West Lafayette, IN.∗∗The study is supported by a grant from NOSCAR/ASGE