title: Multivariate analysis of risk factors for postoperative complications after laparoscopic liver resection.
abstract: BACKGROUND
  The identification of modifiable perioperative risk factors in patients undergoing laparoscopic liver resection (LLR) should aid the selection of appropriate surgical procedures and thus improve further the outcomes associated with LLR. The aim of this retrospective study was to determine the risk factors for postoperative morbidity associated with laparoscopic liver surgery.
  
  
  METHODS
  All patients who underwent elective LLR between January 1999 and December 2012 were included. Demographic data, preoperative risk factors, operative variables, histological analysis, and postoperative course were recorded. Multivariate analysis was carried out using an unconditional logistic regression model.
  
  
  RESULTS
  Between January 1999 and December 2012, 140 patients underwent LLR. There were 56 male patients (40%) and mean age was 57.8 ± 17 years. Postoperative complications were recorded in 30 patients (21.4%). Postoperative morbidity was significantly higher after LLR of malignant tumors [n = 26 (41.3%)] when compared to LLR of benign lesions [n = 4 (5.2%) (P < 0.0001)]. By multivariate analysis, operative time [OR = 1.008 (1.003-1.01), P = 0.001] and LLR performed for malignancy [OR = 9.8 (2.5-37.6); P = 0.01] were independent predictors of postoperative morbidity. In the subgroup of patients that underwent LLR for malignancy using the same multivariate model, operative time was the sole independent predictor of postoperative morbidity [OR = 1.008 (1.002-1.013); P = 0.004].
  
  
  CONCLUSIONS
  Postoperative complication rate increases by 60% with each additional operative hour during LLR. Therefore, expected operative time should be assessed before and during LLR, especially when dealing with malignant tumor.
authors.affiliation: Department of Minimally Invasive Digestive Surgery, Antoine Béclère Hospital, AP-HP, 92140, Clamart, France.
authors.forename: Hadrien
authors.initials: H
authors.lastname: Tranchart
authors.forename: Martin
authors.initials: M
authors.lastname: Gaillard
authors.forename: Mircea
authors.initials: M
authors.lastname: Chirica
authors.forename: Stefano
authors.initials: S
authors.lastname: Ferretti
authors.forename: Gabriel
authors.initials: G
authors.lastname: Perlemuter
authors.forename: Sylvie
authors.initials: S
authors.lastname: Naveau
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Dagher
mesh_terms: D000368:Aged; D019540:Area Under Curve; D016208:Databases, Factual; D005260:Female; D005602:France; D006498:Hepatectomy / Q000009:adverse effects*; D006801:Humans; D010535:Laparoscopy / Q000009:adverse effects*; D008113:Liver Neoplasms / Q000601:surgery*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D061646:Operative Time; D011183:Postoperative Complications / Q000209:etiology* / Q000401:mortality; D012189:Retrospective Studies; D012307:Risk Factors