Elsevier

The Spine Journal

Volume 14, Issue 8, 1 August 2014, Pages 1694-1701
The Spine Journal

Clinical Study
A perioperative cost analysis comparing single-level minimally invasive and open transforaminal lumbar interbody fusion

https://doi.org/10.1016/j.spinee.2013.10.053Get rights and content

Abstract

Background context

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.

Purpose

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.

Study design/setting

This study was a nonrandomized, nonblinded prospective review.

Patient sample

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.

Outcome measures

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.

Introduction

Evidence & Methods

Open and MIS TLIF have become popular fusion techniques for degenerative conditions. The authors aimed to assess their relative costs.

The group found that MIS TLIF, in their hands, afforded shorter operative times, LOS, and improved VAS scores. They also noted a reduction in hospital costs.

The findings are logical and intuitive. MIS should be less morbid, afford more rapid mobilization, and result in less short term costs. However the question of whether less surgery is enough (ie, is the decompression adequate; is solid fusion achieved with a unilateral approach) can be a concern. The ideal method to answer the question would be an RCT. The current study is a comparison of cohorts. Controversy around this methodology and the specifics of this study are discussed in the commentary.

—The Editors

As health care costs continue to grow in the United States, attention has been increasingly focused on evaluating the efficacy, value, and cost-effectiveness of treatments patients receive. Approximately 200,000 lumbar fusions are performed in the United States each year to treat disorders of the spine [1], [2], [3], [4]. As such, it is not surprising that there has been considerable interest in reducing the costs of these procedures [5], [6], [7].

Transforaminal lumbar interbody fusion (TLIF) is commonly used to treat degenerative pathologies of the lumbar spine. Traditionally, TLIF procedures have been performed via an open approach involving retraction of the paraspinal muscles from the midline for the duration of the procedure. With recent advances in microscopy, tissue retractors, and other specialized instruments, spine surgeons can perform this procedure with a minimally invasive surgical (MIS) approach. Reports of MIS TLIF have noted superior results to the traditional open procedure in terms of injury to soft tissue, postoperative back pain, blood loss, need for transfusion, time to ambulation, length of stay (LOS), and functional restoration [8], [9], [10], [11]. Theoretically, these advantages should result in cost savings during the perioperative period.

Although both MIS and open procedures have been shown to safely and effectively treat disorders of the lumbar spine, concerns exist with respect to the costs associated with performing MIS procedures [12], [13], [14]. Furthermore, published data in reference to costs associated with MIS in the lumbar spine are limited [10], [11], [15], [16]. We hypothesize that hospital costs would be decreased for the MIS technique, as LOS, blood loss, and postoperative pain are expected to be less. The purpose of this study was to determine if there are differences in the perioperative costs and charges for patients treated with primary single-level MIS compared with open TLIF. In addition, the cost and charge data will be analyzed to determine factors that contribute to any differences noted.

Section snippets

Patient selection

After obtaining institutional review board approval, we performed a retrospective analysis of hospital costs and payments for patients undergoing TLIF with a diagnosis of either lumbar degenerative disc disease (DDD), degenerative spondylolisthesis, or spinal stenosis. All patients had failed conservative management, including medications, a minimum of 6 weeks of physical therapy, and epidural injections when indicated. All patients were treated at a single academic medical center by two

Demographic characteristics

Sixty-six patients with a mean age of 51 years were treated with a single-level TLIF. Thirty-three patients underwent an MIS TLIF and 33 patients underwent an open TLIF (Figs. 2 and 3). Patients were equally matched according to demographic characteristics (race, age, gender), CCI, diagnosis, smoking status, and type of insurance (Table 2).

Clinical outcomes

The mean surgical time (skin to skin) and anesthesia time (induction of patient to patient's arrival to the postanesthesia care unit) differed significantly

Discussion

The United States is reported to have one of the highest rates of low back surgery in the world [17]. In addition, rates of back surgeries have increased by 55% from 1979 to 1990, and now 21 per 100,000 Medicare beneficiaries undergo a spinal fusion [5], [17], [18]. Furthermore, the complexity of spinal fusions has increased, and Deyo et al. [5] reported that hospital costs associated with complex spine fusions can amount to $80,000 per patient. As a result of the significant resources

Conclusion

MIS TLIF demonstrated a reduction of inpatient resource utilization, resulting in significant cost savings to the hospital when compared with the open procedure. Ironically, hospital profitability was greater with open TLIFs demonstrating the margins that are apparent with increased acute surgical charges. In light of the continued increase in health care expenditure, it becomes imperative to evaluate and understand the efficacy, value, and cost-effectiveness of the surgical interventions that

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    Author disclosures: KS: Royalties: Zimmer (C), Stryker (D), Lippincott (C), Thieme (C); Consulting: Depuy (B), Zimmer (B), Stryker (B). SVN: Nothing to disclose. AM-L: Nothing to disclose. SJF: Nothing to disclose. MO: Nothing to disclose. MAP: Nothing to disclose. GBA: Consulting: Fziomed (B), BioSet (B); Scientific Advisory Board/Other Office: Zimmer, Inc. (C), Pioneer Surgical (B), AlloSource (B); Research Support (Investigator Salary, Staff/Materials): NIH/NIAMS (I, Paid directly to employer); Grants: NIH/NIAMS (I, Paid directly to employer). DI: Nothing to disclose. BJJ: Nothing to disclose. FMP: Royalties: Nuvasive (H), Depuy (E), Medtronic (C), Stryker (C); Stock Ownership: SI Bone (<1%), Axiomed (<1%), Spinal Motion (<1%), Spinal Kinetics (<1%), Pioneer (<1%), Facet Solutions (<1%), Cross Trees (<1%), Flexuspine (<1%), Pearl Diver (<1%).

    The disclosure key can be found on the Table of Contents and at www.TheSpineJournalOnline.com.

    Disclosure: No funds were received in support of this work. No benefits in any form have been or will be received from any commercial party related directly or indirectly to the subject of this manuscript.

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