Elsevier

The Spine Journal

Volume 16, Issue 1, 1 January 2016, Pages 23-31
The Spine Journal

Clinical Study
Economic evaluation comparing intraoperative cone beam CT-based navigation and conventional fluoroscopy for the placement of spinal pedicle screws: a patient-level data cost-effectiveness analysis

https://doi.org/10.1016/j.spinee.2015.09.062Get rights and content

Abstract

Background Context

Pedicle screws are routinely used in contemporary spinal surgery. Screw misplacement may be asymptomatic but is also correlated with potential adverse events. Computer-assisted surgery (CAS) has been associated with improved screw placement accuracy rates. However, this technology has substantial acquisition and maintenance costs. Despite its increasing usage, no rigorous full economic evaluation comparing this technology to current standard of care has been reported.

Purpose

Medical costs are exploding in an unsustainable way. Health economic theory requires that medical equipment costs be compared with expected benefits. To answer this question for computer-assisted spinal surgery, we present an economic evaluation looking specifically at symptomatic misplaced screws leading to reoperation secondary to neurologic deficits or biomechanical concerns.

Study Design/Setting

The study design was an observational case-control study from prospectively collected data of consecutive patients treated with the aid of CAS (treatment group) compared with a matched historical cohort of patients treated with conventional fluoroscopy (control group).

Patient Sample

The patient sample consisted of consecutive patients treated surgically at a quaternary academic center.

Outcome Measures

The primary effectiveness measure studied was the number of reoperations for misplaced screws within 1 year of the index surgery. Secondary outcome measures included were total adverse event rate and postoperative computed tomography usage for pedicle screw examination.

Methods

A patient-level data cost-effectiveness analysis from the hospital perspective was conducted to determine the value of a navigation system coupled with intraoperative 3-D imaging (O-arm Imaging and the StealthStation S7 Navigation Systems, Medtronic, Louisville, CO, USA) in adult spinal surgery. The capital costs for both alternatives were reported as equivalent annual costs based on the annuitization of capital expenditures method using a 3% discount rate and a 7-year amortization period. Annual maintenance costs were also added. Finally, reoperation costs using a micro-costing approach were calculated for both groups. An incremental cost-effectiveness ratio was calculated and reported as cost per reoperation avoided. Based on reoperation costs in Canada and in the United States, a minimal caseload was calculated for the more expensive alternative to be cost saving. Sensitivity analyses were also conducted.

Results

A total of 5,132 pedicle screws were inserted in 502 patients during the study period: 2,682 screws in 253 patients in the treatment group and 2,450 screws in 249 patients in the control group. Overall accuracy rates were 95.2% for the treatment group and 86.9% for the control group. Within 1 year post treatment, two patients (0.8%) required a revision surgery in the treatment group compared with 15 patients (6%) in the control group. An incremental cost-effectiveness ratio of $15,961 per reoperation avoided was calculated for the CAS group. Based on a reoperation cost of $12,618, this new technology becomes cost saving for centers performing more than 254 instrumented spinal procedures per year.

Conclusions

Computer-assisted spinal surgery has the potential to reduce reoperation rates and thus to have serious cost-effectiveness and policy implications. High acquisition and maintenance costs of this technology can be offset by equally high reoperation costs. Our cost-effectiveness analysis showed that for high-volume centers with a similar case complexity to the studied population, this technology is economically justified.

Section snippets

Background

The insertion of pedicle screws within the thoracolumbar spine is routinely performed. There are two main methods of spinal pedicle screw insertion: the computer-assisted surgery (CAS) (“navigated”) technique and the traditional free-hand (“non-navigated”) method. Fluoroscopy-assisted screw insertion is the most popular method when intraoperative navigation is not used. The CAS technique involves the use of intraoperative navigation that necessitates preoperative or intraoperative 2-D or 3-D

Research objective or hypothesis

The goal of this study was to perform a patient-level cost-effectiveness analysis to determine the value of a navigation system coupled with intra-operative 3-D imaging (O-arm and the S7 StealthStation navigation system, Medtronic, Louisville, CO, USA) in adult spinal surgery. By potentially preventing reoperation for symptomatic hardware malposition, we hypothesized that the use of the O-arm and the StealthStation navigation system would be associated with better outcomes and decreased costs

Methods

A patient-level data cost-effectiveness analysis was conducted as described below. This study was based on a single center observational study of prospectively collected data.

Results

Our study comprised a total of 502 patients in whom 5,132 pedicle screws were inserted. The mean age of the study population was 55 years and 51% of the population was male. There were 253 patients who had 2,682 screws inserted using the O-arm or StealthStation navigation system (Group 1), whereas 249 patients had 2,450 screws inserted with the conventional fluoroscopy-assisted method (Group 2). As per our case-matching process, there were no significant differences in age, sex, number of

Discussion

Using rigorous patient-level data and outcomes methodology, we showed that the use of a more accurate technology for spine pedicle screw placement is more cost-effective than previously anticipated. To our knowledge, this report is the first full economic evaluation comparing the usage of cone-beam CT-guided navigation and conventional fluoroscopy for the placement of pedicle screws. Numerous other economic evaluations of adjunct technologies for pedicle screw insertion placement have been

Conclusions

Computer-assisted spinal surgery has the potential to reduce reoperation rates and thus to have important cost-effectiveness implications. High acquisition and maintenance costs of CAS can be offset by high reoperation costs. Our cost-effectiveness analysis has also shown that for high-volume centers (greater than 250 spinal instrumentations annually) with a case-mix and complexity similar to the patient cohort of the present study, this technology is economically justified. We believe that

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  • Cited by (0)

    FDA device/drug status: Approved (O-Arm Imaging system, StealthStation S7 Navigation System, C-Arm Imaging System).

    Author disclosures: ND: Grant: Medtronic (E, Paid directly to institution/employer), pertaining to the submitted work; Speaking and/or Teaching Arrangements (B, Paid directly to author), outside the submitted work. CGF: Board membership: Medtronic, Inc (Grant, Personal fees, Non-financial support, Other), outside the submitted work. JB: Nothing to disclose. JS: Nothing to disclose. DM: Nothing to disclose. SJP: Grant: Medtronic Navigation (F, Paid directly to institution/employer), pertaining to the submitted work. BKK: Grant: Medtronic Navigation (F, Paid directly to institution/employer), pertaining to the submitted work; Fellowship Support: Medtronic, Depuy-Synthes (F, Paid directly to institution/employer), outside the submitted work. MDB: Nothing to disclose. MFSD: Grant: Medtronic (Personal fees, Non-financial support), outside the submitted work. JTS: Grant: Medtronic, Inc, (F, during conduct of the study).

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

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