title: Perioperative characteristics and outcomes of patients undergoing anterior cervical fusion in July: analysis of the "July effect".
abstract: METHODS
  Retrospective national database analysis.
  
  
  OBJECTIVE
  A national population-based database was analyzed to characterize the "July effect" on the perioperative outcomes of anterior cervical fusions (ACFs).
  
  
  BACKGROUND
  Perception biases exist regarding the outcomes of cervical spine surgery based upon the month of admission.
  
  
  METHODS
  The Nationwide Inpatient Sample database was queried from 2009-2011. Patients who underwent an ACF in teaching and nonteaching hospitals were identified and separated into cohorts. Patients who were admitted in July were then compared with non-July admissions in both cohorts. Demographics, Charlson Comorbidity Index, length of stay, costs, postoperative complications, and mortality were assessed.
  
  
  RESULTS
  A total of 52,499 ACF cases were identified in the Nationwide Inpatient Sample of which 26,831 (51.2%) were performed in teaching hospitals and 25,668 (48.8) in nonteaching institutions. July admissions represented 6.8% and 7.4% of cases in the teaching and nonteaching hospital cohorts, respectively. Among July admissions, the teaching cohort incurred a longer hospitalization than the nonteaching cohort (P < 0.05). In contrast, no significant differences in mortality or total hospital costs were demonstrated. In teaching institutions, the in-hospital complications associated with July patients included deep vein thrombosis and surgical site infection (P < 0.05), but this did not reach significance in nonteaching hospitals. Postoperative dysphagia and deep vein thromboses were also significantly more prevalent among July admissions in teaching hospitals compared with nonteaching institutions.
  
  
  CONCLUSIONS
  This national study demonstrated that the early resident academic year was associated with a greater length of stay among July patients in teaching hospitals. This study did not demonstrate an increase in mortality or total hospital costs among July patients in either hospital cohort. In teaching hospitals, ACF-treated patients in July were associated with a greater incidence of postoperative thromboses and surgical site infection. In addition, the incidence of dysphagia was significantly greater among July patients in teaching hospitals than nonteaching hospitals.
authors.affiliation: From the Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL.
authors.forename: Sreeharsha V
authors.initials: SV
authors.lastname: Nandyala
authors.forename: Alejandro
authors.initials: A
authors.lastname: Marquez-Lara
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Fineberg
authors.forename: Kern
authors.initials: K
authors.lastname: Singh
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D017721:Hospital Costs / Q000706:statistics & numerical data; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data; D006784:Hospitals, Teaching / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007297:Inpatients; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D059035:Perioperative Period; D012189:Retrospective Studies; D012621:Seasons; D013123:Spinal Fusion / Q000009:adverse effects* / Q000191:economics / Q000401:mortality*; D016896:Treatment Outcome; D020246:Venous Thrombosis / Q000209:etiology; D055815:Young Adult