title: Conversion-to-open in laparoscopic appendectomy: A cohort analysis of risk factors and outcomes.
abstract: BACKGROUND
  Identifying risk factors for conversion from laparoscopic to open appendectomy could select patients who may benefit from primary open appendectomy. We aimed to develop a predictive scoring model for conversion from laparoscopic to open based on pre-operative patient characteristics.
  
  
  METHODS
  A retrospective review of the State Inpatient Database (2007-2011) was performed using derivation (N = 71,617) and validation (N = 143,235) cohorts of adults ≥ 18 years with acute appendicitis treated by laparoscopic-only (LA), conversion from laparoscopic to open (CA), or primary open (OA) appendectomy. Pre-operative variables independently associated with CA were identified and reported as odds ratios (OR) with 95% confidence intervals (CI). A weighted integer-based scoring model to predict CA was designed based on pre-operative variable ORs, and complications between operative subgroups were compared.
  
  
  RESULTS
  Independent predictors of CA in the derivation cohort were age ≥40 (OR 1.67; CI 1.55-1.80), male sex (OR 1.25; CI 1.17-1.34), black race (OR 1.46; CI 1.28-1.66), diabetes (OR 1.47; CI 1.31-1.65), obesity (OR 1.56; CI 1.40-1.74), and acute appendicitis with abscess or peritonitis (OR 7.00; CI 6.51-7.53). In the validation cohort, the CA predictive scoring model had an optimal cutoff score of 4 (range 0-9). The risk of conversion-to-open was ≤5% for a score <4, compared to 10-25% for a score ≥4. On composite outcomes analysis controlling for all pre-operative variables, CA had a higher likelihood of infectious/inflammatory (OR 1.44; CI 1.31-1.58), hematologic (OR 1.31; CI 1.17-1.46), and renal (OR 1.22; CI 1.06-1.39) complications compared to OA. Additionally, CA had a higher likelihood of infectious/inflammatory, respiratory, cardiovascular, hematologic, and renal complications compared to LA.
  
  
  CONCLUSIONS
  CA patients have an unfavorable complication profile compared to OA. The predictors identified in this scoring model could help select for patients who may benefit from primary open appendectomy.
authors.affiliation: Department of Surgery, New York Presbyterian Hospital - Weill Cornell Medicine, 525 E. 68th Street, New York, NY 10065, United States. Electronic address: bmf9002@nyp.org.
authors.forename: Brendan M
authors.initials: BM
authors.lastname: Finnerty
authors.affiliation: Department of Healthcare Policy and Research, Division of Biostatistics and Epidemiology, Weill Cornell Medicine, 402 East 67th Street, New York, NY 10065, United States. Electronic address: xiw2011@med.cornell.edu.
authors.forename: Xian
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Anesthesia, New York Presbyterian Hospital - Weill Cornell Medicine, 525 E. 68th Street, New York, NY 10065, United States. Electronic address: grg2010@med.cornell.edu.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Giambrone
authors.affiliation: Department of Anesthesia, New York Presbyterian Hospital - Weill Cornell Medicine, 525 E. 68th Street, New York, NY 10065, United States. Electronic address: lig3001@med.cornell.edu.
authors.forename: Licia K
authors.initials: LK
authors.lastname: Gaber-Baylis
authors.affiliation: Department of Computer Science, Cornell University, 402 Gates Hall, Ithaca, NY 14853, United States. Electronic address: rdz@cs.cornell.edu.
authors.forename: Ramin
authors.initials: R
authors.lastname: Zabih
authors.affiliation: Department of Computer Science, Cornell University, 402 Gates Hall, Ithaca, NY 14853, United States. Electronic address: akshayubhat@gmail.com.
authors.forename: Akshay
authors.initials: A
authors.lastname: Bhat
authors.affiliation: Department of Surgery, New York Presbyterian Hospital - Weill Cornell Medicine, 525 E. 68th Street, New York, NY 10065, United States. Electronic address: raz2002@med.cornell.edu.
authors.forename: Rasa
authors.initials: R
authors.lastname: Zarnegar
authors.affiliation: Department of Surgery, New York Presbyterian Hospital - Weill Cornell Medicine, 525 E. 68th Street, New York, NY 10065, United States. Electronic address: alp2014@med.cornell.edu.
authors.forename: Alfons
authors.initials: A
authors.lastname: Pomp
authors.affiliation: Department of Anesthesia, New York Presbyterian Hospital - Weill Cornell Medicine, 525 E. 68th Street, New York, NY 10065, United States. Electronic address: pmf9003@med.cornell.edu.
authors.forename: Peter
authors.initials: P
authors.lastname: Fleischut
authors.affiliation: Department of Surgery, New York Presbyterian Hospital - Weill Cornell Medicine, 525 E. 68th Street, New York, NY 10065, United States. Electronic address: cha9043@med.cornell.edu.
authors.forename: Cheguevara
authors.initials: C
authors.lastname: Afaneh
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D001062:Appendectomy / Q000009:adverse effects* / Q000379:methods; D001064:Appendicitis / Q000601:surgery*; D005260:Female; D006801:Humans; D010535:Laparoscopy / Q000009:adverse effects* / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
keywords: Appendectomy; Conversion to open; Laparoscopic; State inpatient database