title: Learning Curve for Single-Incision Laparoscopic Anterior Resection for Sigmoid Colon Cancer.
abstract: BACKGROUND
  Compared with conventional laparoscopic surgery, single-incision laparoscopic surgery produces better cosmetic benefits. The aim of this study was to investigate the learning curve for single-incision laparoscopic anterior resection (SILAR) for sigmoid colon cancer using multidimensional methods.
  
  
  METHODS
  From September 2009 through May 2014, one hundred and thirteen patients underwent SILAR for sigmoid colon cancer by a single surgeon at Severance Hospital. The learning curve was analyzed using moving average, cumulative sum control chart (CUSUM), and risk-adjusted CUSUM methods. For risk-adjusted CUSUM, surgical failure was defined as conversion to open surgery or conventional laparoscopic surgery, morbidity within 30 days after surgery, <12 harvested lymph nodes, or local recurrence.
  
  
  RESULTS
  Using the moving average method, the peak point for operation time occurred at the 65(th) case (173 minutes). The CUSUM method also showed the operation time peak point at the 65(th) case. However, the risk-adjusted CUSUM curve did not ascend after the 61st case. The operation time and hospital stay for the 60 phase 1 patients (cases 1 to 60) were longer than for 53 phase 2 patients (cases 61 to 113) (166.6 vs 140 minutes; p < 0.001 and 7.1 vs 5.5 days; p = 0.009). Phase 2 patients had a significantly larger tumor diameter and more harvested lymph nodes.
  
  
  CONCLUSIONS
  The learning curve for SILAR for sigmoid colon cancer was 61 to 65 cases according to multidimensional statistical analyses. Single-incision laparoscopic anterior resection is feasible for surgeons experienced in laparoscopic surgery. However, SILAR required more cases for proficiency than the number previously reported for conventional laparoscopic surgery, likely because of its technical challenges.
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Chang Woo
authors.initials: CW
authors.lastname: Kim
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Woo Ram
authors.initials: WR
authors.lastname: Kim
authors.affiliation: Biostatistics Collaboration Unit, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ha Yan
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jeonghyun
authors.initials: J
authors.lastname: Kang
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea. Electronic address: hhyuk@yuhs.ac.
authors.forename: Hyuk
authors.initials: H
authors.lastname: Hur
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Byung Soh
authors.initials: BS
authors.lastname: Min
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seung Hyuk
authors.initials: SH
authors.lastname: Baik
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kang Young
authors.initials: KY
authors.lastname: Lee
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Nam Kyu
authors.initials: NK
authors.lastname: Kim
mesh_terms: D000230:Adenocarcinoma / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003082:Colectomy / Q000193:education / Q000379:methods* / Q000523:psychology; D061887:Conversion to Open Surgery / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D010535:Laparoscopy / Q000193:education / Q000379:methods* / Q000523:psychology; D059032:Learning Curve; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D061646:Operative Time; D056910:Republic of Korea; D012189:Retrospective Studies; D020379:Risk Adjustment; D012811:Sigmoid Neoplasms / Q000601:surgery*; D016896:Treatment Outcome