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Pain Research and Treatment
Volume 2012, Article ID 823509, 10 pages
Clinical Study

Interspinous Spacer Implant in Patients with Lumbar Spinal Stenosis: Preliminary Results of a Multicenter, Randomized, Controlled Trial

1Miller Scientific Consulting, Inc., 26 Portobello Road, Arden, NC 28704, USA
2The Jon Block Group, 2210 Jackson Street, Suite 401, San Francisco, CA 94115, USA

Received 24 June 2011; Revised 26 September 2011; Accepted 24 October 2011

Academic Editor: Howard S. Smith

Copyright © 2012 Larry E. Miller and Jon E. Block. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A prospective, randomized, controlled trial was conducted to compare clinical outcomes in patients treated with an investigational interspinous spacer (Superion) versus those treated with an FDA-approved spacer (X-STOP). One hundred sixty-six patients with moderate lumbar spinal stenosis (LSS) unresponsive to conservative care were treated randomly with the Superion or X-STOP interspinous spacer. Study subjects were followed through 6 months posttreatment. Zurich Claudication Questionnaire (ZCQ) symptom severity scores improved 30% with Superion and 25% with X-STOP (both ). Similar changes were noted in ZCQ physical function with improvements of 32% with Superion and 27% with X-STOP (both ). Mean ZCQ patient satisfaction score ranged from 1.7 to 2.0 in both groups at all follow-up visits. The proportion of subjects that achieved at least two of three ZCQ clinical success criteria at 6 months was 75% with Superion and 67% with X-STOP. Axial pain decreased from  mm at pretreatment to  mm at 6 months in the Superion group ( ) and from  mm to  mm with X-STOP ( ). Extremity pain decreased from  mm at pretreatment to  mm at 6 months in the Superion group ( ) and from  mm to  mm with X-STOP ( ). Back function improved from % to % with Superion ( ) and from % to % with X-STOP ( ). Preliminary results suggest that the Superion interspinous spacer and the X-STOP each effectively alleviate pain and improve back function in patients with moderate LSS who are unresponsive to conservative care.