title: Safety of Overlapping Surgery at a High-volume Referral Center.
abstract: OBJECTIVE
  To compare safety profiles of overlapping and nonoverlapping surgical procedures at a large tertiary-referral center where overlapping surgery is performed.
  
  
  BACKGROUND
  Surgical procedures are frequently performed as overlapping, wherein one surgeon is responsible for 2 procedures occurring at the same time, but critical portions are not coincident. The safety of this practice has not been characterized.
  
  
  METHODS
  Primary analyses included elective, adult, inpatient surgical procedures from January 2013 to September 2015 available through University HealthSystem Consortium. Overlapping and nonoverlapping procedures were matched in an unbalanced manner (m:n) by procedure type. Confirmatory analyses from the American College of Surgeons-National Surgical Quality Improvement Program investigated elective surgical procedures from January 2011 to December 2014. We compared outcomes mortality and length of stay after adjustment for registry-predicted risk, case-mix, and surgeon using mixed models.
  
  
  RESULTS
  The University HealthSystem Consortium sample included 10,765 overlapping cases, of which 10,614 (98.6%) were matched to 16,111 nonoverlapping procedures. Adjusted odds ratio for inpatient mortality was greater for nonoverlapping procedures (adjusted odds ratio, OR = 2.14 vs overlapping procedures; 95% confidence interval, CI 1.23-3.73; P = 0.007) and length of stay was no different (+1% for nonoverlapping cases; 95% CI, -1% to +2%; P = 0.50). In confirmatory analyses, 93.7% (3712/3961) of overlapping procedures matched to 5,637 nonoverlapping procedures. The 30-day mortality (adjusted OR = 0.69 nonoverlapping vs overlapping procedures; 95% CI, 0.13-3.57; P = 0.65), morbidity (adjusted OR = 1.11; 95% CI, 0.92-1.35; P = 0.27) and length of stay (-4% for nonoverlapping; 95% CI, -4% to -3%; P < 0.001) were not clinically different.
  
  
  CONCLUSIONS
  These findings from administrative and clinical registries support the safety of overlapping surgical procedures at this center but may not extrapolate to other centers.
authors.affiliation: *Department of Anesthesiology, Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN †Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN ‡Department of Anesthesiology, Mayo Clinic, Rochester, MN §Department of Surgery, Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Hyder
authors.forename: Kristine T
authors.initials: KT
authors.lastname: Hanson
authors.forename: Curtis B
authors.initials: CB
authors.lastname: Storlie
authors.forename: Amy
authors.initials: A
authors.lastname: Glasgow
authors.forename: Nageswar R
authors.initials: NR
authors.lastname: Madde
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Brown
authors.forename: Daryl J
authors.initials: DJ
authors.lastname: Kor
authors.forename: Robert R
authors.initials: RR
authors.lastname: Cima
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Habermann
mesh_terms: D000328:Adult; D016001:Confidence Intervals; D017558:Elective Surgical Procedures / Q000009:adverse effects / Q000379:methods / Q000401:mortality; D005260:Female; D017052:Hospital Mortality / Q000639:trends*; D061847:Hospitals, High-Volume; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care; D061214:Patient Safety; D011183:Postoperative Complications / Q000453:epidemiology / Q000503:physiopathology; D012017:Referral and Consultation; D012042:Registries; D012189:Retrospective Studies; D018570:Risk Assessment; D017751:Safety Management; D013514:Surgical Procedures, Operative / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D014481:United States