title: Clinical outcomes of robot-assisted intersphincteric resection for low rectal cancer: comparison with conventional laparoscopy and multifactorial analysis of the learning curve for robotic surgery.
abstract: BACKGROUND
  This study evaluated the feasibility of robot-assisted intersphincteric resection (ISR) for low rectal cancer. Further, we attempted to analyze the learning curve for robotic surgery.
  
  
  METHODS
  A total of 64 patients were retrospectively chart-reviewed. Patients were classified into a laparoscopic procedure (n = 28) group and a robot-assisted (n = 36) group. Comparisons of age, gender, clinical staging, operating time, complications, and pathologic status were analyzed. Besides, we used a seventh-order moving average method for the construction of a learning curve in robotic surgery.
  
  
  RESULTS
  Operating time was 374.3 min (range, 210-570 min) in the laparoscopic group and 485.8 min (range, 315-720 min) in the robotic group, with statistical difference between these two groups (P < 0.001). Thirteen patients (46.4 %) received diverting stoma in the laparoscopic group and seven patients (19.4 %) in the robotic group, with statistical difference between these two groups (P = 0.021). Operative experience of robotic ISR showed that the mean operating time was 519.5 min (range, 360-720 min) in the first stage and 448.2 min (range, 315-585 min) in the second stage, with statistical difference between these two stages (P = 0.02). Multifactorial analysis showed that protective diverting stoma creation or neorectum necrosis was not associated with age, sex, pretreatment T stage, or surgeons' experience.
  
  
  CONCLUSIONS
  Our data shows that robot-assisted ISR for low rectal cancer is feasible and safe with no compromising oncological outcomes. The surgeons' experience improves operating time in robotic surgery.
authors.affiliation: Division of General Surgery, Department of Surgery, Taipei Medical University Hospital, Taipei, Taiwan, kuolijen@gmail.com.
authors.forename: Li-Jen
authors.initials: LJ
authors.lastname: Kuo
authors.forename: Yen-Kuang
authors.initials: YK
authors.lastname: Lin
authors.forename: Chun-Chao
authors.initials: CC
authors.lastname: Chang
authors.forename: Cheng-Jeng
authors.initials: CJ
authors.lastname: Tai
authors.forename: Jeng-Fong
authors.initials: JF
authors.lastname: Chiou
authors.forename: Yu-Jia
authors.initials: YJ
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000473:pathology / Q000601:surgery*; D005240:Feasibility Studies; D006801:Humans; D010535:Laparoscopy / Q000009:adverse effects / Q000379:methods*; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D061646:Operative Time; D011183:Postoperative Complications; D012004:Rectal Neoplasms / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D012371:Robotics; D054047:Surgical Stomas; D016896:Treatment Outcome; D055815:Young Adult