Two-year clinical outcomes of a multicenter randomized controlled trial comparing two interspinous spacers for treatment of moderate lumbar spinal stenosis

BMC Musculoskelet Disord. 2014 Jul 5;15:221. doi: 10.1186/1471-2474-15-221.

Abstract

Background: Interspinous spacers are a minimally invasive surgical alternative for patients with lumbar spinal stenosis (LSS) unresponsive to conservative care. The purpose of this prospective, multicenter, randomized, controlled trial was to compare 2-year clinical outcomes in patients with moderate LSS treated with the Superion(®) (Experimental) or the X-Stop(®), a FDA-approved interspinous spacer (Control).

Methods: A total of 250 patients with moderate LSS unresponsive to conservative care were randomly allocated to treatment with the Experimental (n = 123) or Control (n = 127) interspinous spacer and followed through 2 years post-treatment. Complication data were available for all patients and patient-reported outcomes were available for 192 patients (101 Experimental, 91 Control) at 2 years.

Results: Zurich Claudication Questionnaire (ZCQ) Symptom Severity and Physical Function scores improved 34% to 36% in both groups through 2 years (all p < 0.001). Patient Satisfaction scores at 2 years were 1.8 ± 0.9 with Experimental and 1.6 ± 0.8 with Control. Axial pain decreased from 59 ± 26 mm at baseline to 21 ± 26 mm at 2 years with Experimental and from 55 ± 26 mm to 21 ± 25 mm with Control (both p < 0.001). Extremity pain decreased from 67 ± 24 mm to 14 ± 22 mm at 2 years with Experimental and from 63 ± 24 mm to 18 ± 23 mm with Control (both p < 0.001). Back function assessed with the Oswestry Disability Index similarly improved with Experimental (37 ± 12% to 18 ± 16%) and Control (39 ± 12% to 20 ± 16%) (both p < 0.001). Freedom from reoperation at the index level was 84% for Experimental and 83% for Control (log-rank: p = 0.38) at 2 years.

Conclusions: Both interspinous spacers effectively alleviated pain and improved back function to a similar degree through 2 years in patients with moderate LSS who were unresponsive to conservative care.

Trial registration: NCT00692276.

Publication types

  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Back Pain / etiology
  • Back Pain / prevention & control
  • Disability Evaluation
  • Equipment Design
  • Female
  • Humans
  • Lumbar Vertebrae / diagnostic imaging
  • Lumbar Vertebrae / physiopathology
  • Lumbar Vertebrae / surgery*
  • Male
  • Orthopedic Procedures / adverse effects
  • Orthopedic Procedures / instrumentation*
  • Pain Measurement
  • Pain, Postoperative / etiology
  • Pain, Postoperative / prevention & control
  • Patient Satisfaction
  • Predictive Value of Tests
  • Prospective Studies
  • Radiography
  • Recovery of Function
  • Spinal Stenosis / complications
  • Spinal Stenosis / diagnosis
  • Spinal Stenosis / physiopathology
  • Spinal Stenosis / surgery*
  • Surveys and Questionnaires
  • Time Factors
  • Treatment Outcome
  • United States

Associated data

  • ClinicalTrials.gov/NCT00692276