Interspinous process devices versus standard conventional surgical decompression for lumbar spinal stenosis: cost-utility analysis

Spine J. 2016 Jun;16(6):702-10. doi: 10.1016/j.spinee.2014.10.017. Epub 2014 Oct 23.


Background context: In the 1980s, a new implant was developed to treat patients with intermittent neurogenic claudication caused by lumbar spinal stenosis (LSS). This implant is now widely used.

Purpose: The objective of this study is to determine whether a favorable cost-effectiveness for interspinous process devices (IPDs) compared with conventional bony decompression is attained.

Study design/setting: Cost-utility analysis was performed alongside a double-blind randomized controlled trial. Five neurosurgical centers (including one academic and four secondary level care centers) included participants for this study.

Patient sample: One hundred fifty-nine patients with LSS were treated with the implantation of IPD and with bony decompression. Eighty participants received an IPD, and seventy-nine participants underwent spinal bony decompression.

Outcome measures: Outcome measures were quality-adjusted life-years (QALYs) and societal costs in the first year (estimated per quarter), estimated from patient-reported utilities (US and The Netherlands EuroQol 5D [EQ-5D] and EuroQol visual analog scale) and diaries on costs (health-care costs, patient costs, and productivity costs).

Methods: All analyses followed the intention-to-treat principle. Given the statistical uncertainty of differences between costs and QALYs, cost-effectiveness acceptability curves graph the probability that a strategy is cost effective, as a function of willingness to pay. Paradigm Spine funded this trial but did not have any part in data analysis or the design and preparation of this article.

Results: According to the EQ-5D, the valuation of quality of life after IPD and decompression was not different. Mean utilities during all four quarters were, not significantly, less favorable after IPD according to the EQ-5D with a decrease in QALYs according to the US EQ-5D of 0.024 (95% confidence interval, -0.031 to 0.079). From a health-care perspective, the costs of IPD treatment were higher (difference €3,030 per patient, 95% confidence interval, €561-€5,498). This significant difference is mainly because of additional cost of implants of €2,350 apiece. From a societal perspective, a nonsignificant difference of €2,762 (95% confidence interval, -€1,572 to €7,095) in favor of conventional bony decompression was found.

Conclusions: Implantation of IPD as indirect decompressing device is highly unlikely to be cost effective compared with bony decompression for patients with intermittent neurogenic claudication caused by LSS.

Trial registration: Dutch Trial Register Number: NTR1307.

Keywords: Cost-utility; Degenerative disease; Health-care costs; Lumbar spinal stenosis; Societal costs; Spinal implants.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Cost-Benefit Analysis*
  • Decompression, Surgical / economics*
  • Decompression, Surgical / instrumentation
  • Decompression, Surgical / methods
  • Double-Blind Method
  • Female
  • Humans
  • Lumbar Vertebrae / surgery*
  • Male
  • Middle Aged
  • Netherlands
  • Prostheses and Implants / adverse effects
  • Prostheses and Implants / economics*
  • Quality of Life
  • Quality-Adjusted Life Years
  • Spinal Stenosis / surgery*