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Interspinous Spacers Compared With Decompression or Fusion for Lumbar Stenosis: Complications and Repeat Operations in the Medicare Population

Deyo, Richard A., MD, MPH*,†,‡,§; Martin, Brook I., PhD, MPH¶,‖; Ching, Alex, MD**; Tosteson, Anna N. A., ScD; Jarvik, Jeffrey G., MD, MPH‡‡; Kreuter, William, MPA††; Mirza, Sohail K., MD, MPH¶,‖

doi: 10.1097/BRS.0b013e31828631b8

Study Design. Retrospective cohort analysis of Medicare claims for 2006–2009.

Objective. To examine whether interspinous distraction procedures are used selectively in patients with more advanced age or comorbidity, and whether they are associated with fewer complications, lower costs, and less revision surgery than laminectomy or fusion surgery.

Summary of Background Data. A manufacturer-sponsored randomized trial suggested an advantage of interspinous spacer surgery compared with nonsurgical care, but there are few comparisons with other surgical procedures. Furthermore, there are few population-based data evaluating patterns of use of these devices.

Methods. We used Medicare inpatient claims data to compare age and comorbidity for patients with spinal stenosis undergoing surgery (n = 99,084) with (1) an interspinous process spacer alone; (2) laminectomy and a spacer; (3) decompression alone; or (4) lumbar fusion (1–2 level). We also compared these 4 groups for cost of surgery and rates of revision surgery, major medical complications, wound complications, mortality, and 30-day readmission rates.

Results. Patients who received spacers were older than those undergoing decompression or fusion, but had little evidence of greater comorbidity. Patients receiving a spacer alone had fewer major medical complications than those undergoing decompression or fusion surgery (1.2% vs. 1.8% and 3.3%, respectively), but had higher rates of further inpatient lumbar surgery (16.7% vs. 8.5% for decompression and 9.8% for fusion at 2 yr). Hospital payments for spacer surgery were greater than those for decompression alone but less than for fusion procedures. These associations persisted in multivariate models adjusting for patient age, sex, comorbidity score, and previous hospitalization.

Conclusion. Compared with decompression or fusion, interspinous distraction procedures pose a trade-off in outcomes: fewer complications for the index operation, but higher rates of revision surgery. This information should help patients make more informed choices, but further research is needed to define optimal indications for these new devices.

Level of Evidence: 4

Using Medicare data, we compared patients with lumbar stenosis who received an interspinous process spacer alone; spacer plus decompression; decompression alone; or who underwent a procedure involving fusion. Patients receiving a spacer alone had fewer medical complications than those undergoing decompression or fusion surgery, but had higher rates of revision surgery.

*Department of Family Medicine

Department of Medicine

Department of Public Health and Preventive Medicine

§Center for Research in Occupational and Environmental

Department of Orthopaedics, The Dartmouth Institute for Health Policy and Clinical Practice;

Multidisciplinary Clinical Research Center in Musculoskeletal Diseases, The Geisel School of Medicine at Dartmouth, Hanover, NH;

**Department of Orthopaedics, Oregon Health and Science Univeristy, Portland, OR; and

††Departments of Health Services and

‡‡Department of Radiology, University of Washington, Seattle, WA

Address correspondence and reprint requests to Richard A. Deyo, MD, MPH, Department of Family Medicine, Mail Code FM, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239; E-mail:

Acknowledgment date: August 10, 2012. First revision date: October 19, 2012. Acceptance date: November 17, 2012.

The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication.

The Agency for Health Care Policy Research Grant's funds (1R01AR054912-01A2, NIH/NIAMS, 1 UL1 RR024140–01, NIH/NCRR, NIH/NIA RC1AG036268, and R01HS018405) were received to support this work.

Relevant financial activities outside the submitted work: consultancy, board membership, payment for manuscript preparation, patents, royalties, stock/stock options, and travel accommodations/meeting expenses.

© 2013 by Lippincott Williams & Wilkins