447 - Minimally Invasive versus Open Transforaminal Lumbar Interbody Fusion...

#447 Minimally Invasive versus Open Transforaminal Lumbar Interbody Fusion (TLIF) for Degenerative Spondylolisthesis: Comparative Effectiveness and Cost-utility Analysis

General Session: Advocacy of MIS

Presented by: S. Parker

Author(s):

S.L. Parker (1)
S. Godil (1)
S. Mendenhall (1)
D. Shau (1)
S. Zuckerman (1)
M.J. McGirt (1)

(1) Vanderbilt University Medical Center, Neurological Surgery, Nashville, TN, USA

Abstract

Background: Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) for spondylolisthesis allows for surgical treatment of back and leg pain while theoretically minimizing tissue injury and accelerating overall recovery. Although prior results have consistently shown shorter hospital stays and decreased intraoperative blood loss for MIS vs. open TLIF, short- and long-term outcomes have been similar. The effect of MIS vs. open TLIF on comprehensive healthcare cost is poorly understood. We performed a two-year prospective comparative effectiveness and cost-utility study for MIS vs. open TLIF.

Methods: 100 patients (50 MIS, 50 open) undergoing TLIF for degenerative lumbar spondylolisthesis-associated back and leg pain were entered into an institutional registry and prospectively followed. Baseline, 3-month, and 2-year patient-reported outcomes (PRO) were prospectively assessed via phone interviews. Total back-related medical resource utilization, missed work, and health-state values (quality adjusted life years (QALYs) were assessed by patient interview. Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts and work-day losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). Difference in mean total cost per QALY gained for MIS- versus open-TLIF was assessed as incremental cost-effectiveness ratio (ICER: 2-year costMIS-2-year costopen / QALY gainedMIS-QALY gainedopen).

Results: MIS vs. open TLIF cohorts were similar at baseline. Median [IQR] length of hospitalization and time to return to work were both less for MIS vs. open TLIF: 3 [2-4] days vs. 4 [3-5] days, p=0.006 and 7 [4-11] weeks vs. 11 [9-16] weeks; p=0.03, respectively. MIS vs. open TLIF patients demonstrated similar 3-month and 2-year improvement in all PRO measures assessed, Figure 1. MIS vs. open TLIF was associated with an $8,474 reduction in mean indirect cost (p=0.06), but similar 2-year direct healthcare cost, Figure 2. MIS vs. open TLIF was associated with a reduced total two-year societal cost: $38,563 ± 10,594 vs. $47,858 ± 20,148 (p=0.03) with a similar QALY-gained: 0.771 vs. 0.695 (p=0.343), Figure 1.

Conclusions: MIS TLIF resulted in reduced operative blood loss, reduced hospital stay, accelerated return to work, and reduced two-year cost. Surgical morbidity, hospital re-admission, and short- and long-term clinical effectiveness were similar for MIS and open TLIF. Both MIS and open TLIF are effective treatments for degenerative spondylolisthesis. MIS TLIF may represent a valuable and cost saving advancement.

Figure 1

Figure 2