Postoperative Pain Medication Requirements in Patients Undergoing Computer-Assisted (“Robotic”) and Standard Laparoscopic Procedures for Newly Diagnosed Endometrial Cancer

Abstract

Laparoscopy (LSC) offers superior patient outcomes compared to laparotomy. Small retrospective/prospective series have suggested robotics offers further reduction in postoperative pain and pain medication use compared to standard LSC. Our objective was to compare postoperative pain in patients undergoing robotically assisted (RBT) versus standard LSC for newly diagnosed endometrial cancer. All preoperative endometrial cancer cases scheduled for RBT and LSC from May 1, 2007 to June 9, 2010 were identified. For this analysis, we only included cases not requiring conversion to laparotomy. All patients were offered intravenous (IV) patient-controlled analgesia (PCA) postoperatively. Intraoperative equivalent fentanyl doses (IEFDs) and pain scores in the postanesthesia care unit (PACU) were assessed. IV PCA was used in 206 RBTs (86 %) and 208 LSCs (88 %). Median IEFD was 425 μg for LSCs and 500 μg for RBTs (P = 0.03). Median pain scores on PACU arrival were similar in both groups. Median highest pain score was 5 for LSCs and 4 for RBTs (P = 0.007). Linear regression demonstrated that the IEFD was not correlated with the highest pain score (R = 0.09; P = 0.07). Fentanyl was used postoperatively in 196 of 206 RBTs (95 %) and 187 of 208 LSCs (90 %). The total fentanyl doses were 242.5 (range 0-2705) μg and 380 (range 0-2625) μg, respectively (P < 0.001). The median hourly fentanyl doses were 16.7 (range 0-122.5) μg and 23.5 (range 0-132.4) μg, respectively (P = 0.005). Simultaneous multiple regression analysis further demonstrated RBT was independently associated with a lower total fentanyl dose compared to LSC (P = 0.02). RBT is independently associated with significantly lower postoperative pain and pain medication requirements compared to LSC. The amount of intraoperative fentanyl analgesia does not appear to correlate with postoperative pain.Endometrial cancer is the most common gynecologic malignancy in the United States, with an estimated 47,130 new cases in 2012.1 An estimated 287,100 women were diagnosed with endometrial cancer worldwide in 2008.2 Surgery is the primary treatment of choice for the majority of these women.3 The standard surgical approach has been total abdominal hysterectomy, bilateral salpingo-oophorectomy, and staging via laparotomy. Multiple retrospective series have shown that a less invasive surgical approach via laparoscopy (LSC) is feasible and safe, and also associated with improved perioperative outcomes compared to laparotomy in these patients.4 The Gynecologic Oncology Group (GOG) published results of the largest randomized trial (LAP2) comparing LSC to laparotomy in patients with newly diagnosed endometrial carcinoma in 2009.5,6 This landmark study essentially changed the accepted standard surgical approach in this group. Postoperative complications, median blood loss, and median length of stay (LOS), despite increased operative time, were significantly lower in LSC patients despite 25 % requiring conversion to laparotomy.5 The first 802 eligible patients randomized in LAP2 also participated in a quality-of-life (QOL) study. Within 6 weeks of surgery, patients assigned to LSC reported significantly better QOL on all scales other than fear of recurrence.6 Overall, during this 6-week postoperative period, patients assigned to LSC had superior QOL, fewer physical symptoms, less pain and pain-related interference with functioning, better physical functioning and emotional state, earlier resumption of normal activities, earlier return to work, and better body image compared to those assigned to laparotomy.6 Recurrence-free and overall survivals were the same in both groups.7 Multiple published retrospective series have shown possible benefits, such as reduced postoperative pain, using the robotic (RBT) platform compared to LSC or laparotomy in patients with endometrial cancer.8-11 In a randomized trial, LSC was found to be associated with less postoperative pain compared to vaginal approaches in patients undergoing hysterectomy for benign gynecologic disease.12 A small retrospective series reported further reductions in postoperative pain in patients who had undergone an RBT hysterectomy compared to a standard total LSC hysterectomy for benign indications.13 A recent cost analysis suggested that patients experienced less pain and required less pain medication use after RBT procedures compared to LSC for endometrial cancer.14 Based on these reports, we sought to analyze postoperative pain and the use of pain medication in patients undergoing RBT compared to standard transperitoneal LSC procedures for newly diagnosed endometrial cancer during a concurrent time period. Of note, current RBT surgery is not truly robotic in that it is not autonomous. A more appropriate term is “computer-assisted surgery,” but to satisfy current convention, we refer to it as “robotic surgery” in this manuscript.