title: Learning curve of single port laparoscopic cholecystectomy determined using the non-linear ordinary least squares method based on a non-linear regression model: An analysis of 150 consecutive patients.
abstract: BACKGROUND
  Single port laparoscopic surgery has come to the forefront of minimally invasive surgery. For those familiar with conventional techniques, however, this type of operation demands a different type of eye/hand coordination and involves unfamiliar working instruments. Herein, the authors describe the learning curve and the clinical outcomes of single port laparoscopic cholecystectomy for 150 consecutive patients with benign gallbladder disease.
  
  
  METHODS
  All patients underwent single port laparoscopic cholecystectomy using a homemade glove port by one of five operators with different levels of experiences of laparoscopic surgery. The learning curve for each operator was fitted using the non-linear ordinary least squares method based on a non-linear regression model.
  
  
  RESULTS
  Mean operating time was 77.6 ± 28.5 min. Fourteen patients (6.0%) were converted to conventional laparoscopic cholecystectomy. Complications occurred in 15 patients (10.0%), as follows: bile duct injury (n = 2), surgical site infection (n = 8), seroma (n = 2), and wound pain (n = 3). One operator achieved a learning curve plateau at 61.4 min per procedure after 8.5 cases and his time improved by 95.3 min as compared with initial operation time. Younger surgeons showed significant decreases in mean operation time and achieved stable mean operation times. In particular, younger surgeons showed significant decreases in operation times after 20 cases.
  
  
  CONCLUSIONS
  Experienced laparoscopic surgeons can safely perform single port laparoscopic cholecystectomy using conventional or angled laparoscopic instruments. The present study shows that an operator can overcome the single port laparoscopic cholecystectomy learning curve in about eight cases.
authors.affiliation: Department of Surgery, Korea University Ansan Hospital, Ansan, Gyeonggi-do, 425-707, Republic of Korea.
authors.forename: Hyung Joon
authors.initials: HJ
authors.lastname: Han
authors.forename: Sae Byeol
authors.initials: SB
authors.lastname: Choi
authors.forename: Man Sik
authors.initials: MS
authors.lastname: Park
authors.forename: Jin Suk
authors.initials: JS
authors.lastname: Lee
authors.forename: Wan Bae
authors.initials: WB
authors.lastname: Kim
authors.forename: Tae Jin
authors.initials: TJ
authors.lastname: Song
authors.forename: Sang Yong
authors.initials: SY
authors.lastname: Choi
mesh_terms: D017081:Cholecystectomy, Laparoscopic / Q000193:education* / Q000295:instrumentation; D005260:Female; D005705:Gallbladder Diseases / Q000601:surgery*; D006801:Humans; D020706:Laparoscopes; D059032:Learning Curve; D008297:Male; D015233:Models, Statistical; D012189:Retrospective Studies