title: A perioperative cost analysis comparing single-level minimally invasive and open transforaminal lumbar interbody fusion.
abstract: BACKGROUND
  Emerging literature suggests superior clinical short- and long-term outcomes of MIS (minimally invasive surgery) TLIFs (transforaminal lumbar interbody fusion) versus open fusions. Few studies to date have analyzed the cost differences between the two techniques and their relationship to acute clinical outcomes.
  
  
  OBJECTIVE
  The purpose of the study was to determine the differences in hospitalization costs and payments for patients treated with primary single-level MIS versus open TLIF. The impact of clinical outcomes and their contribution to financial differences was explored as well.
  
  
  METHODS
  This study was a nonrandomized, nonblinded prospective review.
  
  
  METHODS
  Sixty-six consecutive patients undergoing a single-level TLIF (open/MIS) were analyzed (33 open, 33 MIS). Patients in either cohort (MIS/open) were matched based on race, sex, age, smoking status, medical comorbidities (Charlson Comorbidity index), payer, and diagnosis. Every patient in the study had a diagnosis of either degenerative disc disease or spondylolisthesis and stenosis.
  
  
  METHODS
  Operative time (minutes), length of stay (LOS, days), estimated blood loss (EBL, mL), anesthesia time (minutes), Visual Analog Scale (VAS) scores, and hospital cost/payment amount were assessed.
  
  
  METHODS
  The MIS and open TLIF groups were compared based on clinical outcomes measures and hospital cost/payment data using SPSS version 20.0 for statistical analysis. The two groups were compared using bivariate chi-squared analysis. Mann-Whitney tests were used for non-normal distributed data. Effect size estimate was calculated with the Cohen d statistic and the r statistic with a 95% confidence interval.
  
  
  RESULTS
  Average surgical time was shorter for the MIS than the open TLIF group (115.8 minutes vs. 186.0 minutes respectively; p=.001). Length of stay was also reduced for the MIS versus the open group (2.3 days vs. 2.9 days, respectively; p=.018). Average anesthesia time and EBL were also lower in the MIS group (p<.001). VAS scores decreased for both groups, although these scores were significantly lower for the MIS group (p<.001). Financial analysis demonstrated lower total hospital direct costs (blood, imaging, implant, laboratory, pharmacy, physical therapy/occupational therapy/speech, room and board) in the MIS versus the open group ($19,512 vs. $23,550, p<.001). Implant costs were similar (p=.686) in both groups, although these accounted for about two-thirds of the hospital direct costs in the MIS cohort ($13,764) and half of these costs ($13,778) in the open group. Hospital payments were $6,248 higher for open TLIF patients compared with the MIS group (p=.267).
  
  
  CONCLUSIONS
  MIS TLIF technique demonstrated significant reductions of operative time, LOS, anesthesia time, VAS scores, and EBL compared with the open technique. This reduction in perioperative parameters translated into lower total hospital costs over a 60-day perioperative period. Although hospital reimbursements appear higher in the open group over the MIS group, shorter surgical times and LOS days in the MIS technique provide opportunities for hospitals to reduce utilization of resources and to increase surgical case volume.
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St, Chicago, IL 60612, USA. Electronic address: kernsingh@hotmail.com.
authors.forename: Kern
authors.initials: K
authors.lastname: Singh
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St, Chicago, IL 60612, USA.
authors.forename: Sreeharsha V
authors.initials: SV
authors.lastname: Nandyala
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St, Chicago, IL 60612, USA.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Marquez-Lara
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St, Chicago, IL 60612, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Fineberg
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St, Chicago, IL 60612, USA.
authors.forename: Mathew
authors.initials: M
authors.lastname: Oglesby
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St, Chicago, IL 60612, USA.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Pelton
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St, Chicago, IL 60612, USA.
authors.forename: Gunnar B
authors.initials: GB
authors.lastname: Andersson
authors.affiliation: Rush University Medical Center, 1611 W. Harrison St, Chicago, IL 60612, USA.
authors.forename: Darya
authors.initials: D
authors.lastname: Isayeva
authors.affiliation: Rush University Medical Center, 1611 W. Harrison St, Chicago, IL 60612, USA.
authors.forename: Briana J
authors.initials: BJ
authors.lastname: Jegier
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St, Chicago, IL 60612, USA.
authors.forename: Frank M
authors.initials: FM
authors.lastname: Phillips
mesh_terms: D000328:Adult; D003365:Costs and Cost Analysis; D005260:Female; D017721:Hospital Costs; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000191:economics* / Q000601:surgery; D007902:Length of Stay / Q000191:economics; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000191:economics* / Q000379:methods; D011446:Prospective Studies; D013123:Spinal Fusion / Q000191:economics* / Q000379:methods; D013168:Spondylolisthesis / Q000191:economics* / Q000601:surgery; D013995:Time; D016896:Treatment Outcome
keywords: Costs; Minimally invasive spine surgery; Outcomes; Payments; Reimbursements; TLIF