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Articles Included in This Study, Ranked by Level of Evidence, Study Design, Follow-up, and Outcome Measures. ( All studies from Pub Med search in English language peer reviewed journal for Therapeutic Studies . Studies without functional outcome measures and with abstracts only excluded)

Favorable Studies : Two 2 Star**
Unfavorable Studies: Three : One 3 Star***, Two 2 Star**

OVERALL AME Rating : 2 Star ** POOR predictive value for success of procedure
Preponderance of studies are unfavorable. Strength of favorable studies is 2 star.

AEM Rating 1 star – POOR : less than 50% are Level III or greater. Total studies less than 10

Note: FDA advisory panel voted NON-APPROVAL based on study #1, Zucherman, et al.

1. A Multicenter, Prospective, Randomized Trial Evaluating the X STOP Interspinous Process Decompression System for the Treatment of Neurogenic Intermittent Claudication

Two-Year Follow-Up Results James F. Zucherman, MD, Ken Y. Hsu, MD,* Charles A. Hartjen, MD, Thomas F. Mehalic, MD, Dante A. Implicito, MD, Michael J. Martin, MD, Donald R. Johnson II, MD, Grant A. Skidmore, MD, Paul P. Vessa, MD, James W. Dwyer, MD, Stephen T. Puccio, MD, Joseph C. Cauthen MD, and Richard M. Ozuna, MD

2. One-Year Results of X STOP Interspinous Implant for the Treatment of Lumbar Spinal Stenosis

Manal Siddiqui, FRCS,* Francis W. Smith, MD,† and Douglas Wardlaw, FRCS, ChM*

One-Year Results of X STOP Interspinous Implant for the Treatment of Lumbar Spinal Stenosis

Manal Siddiqui, FRCS,* Francis W. Smith, MD, and Douglas Wardlaw, FRCS, ChM*

3. Lee J, Hida K, Seti T, et al. An interspinous process distractor (X STOP) for lumbar spinal stenosis in elderly patients: preliminary experience in 10 consecutive cases. J Spinal Disord 2004;17:72–82.

4. Eur Spine J. 2008 Feb;17(2):200-3. Epub 2007 Oct 31. Links.

Self-rated evaluation of outcome of the implantation of interspinous process distraction (X-Stop) for neurogenic claudication.

Brussee P, Hauth J, Donk RD, Verbeek AL, Bartels RH.

Faculty of Medical Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands.

The treatment of lumbar spinal stenosis is either conservative or surgical decompression. Recently, an interspinous decompression device (X-Stop) has been developed as an alternative. Patients treated with an X-Stop between 2003 and 2006 are subject of this study. The SF-36 Health Survey and Zürich Questionnaires are used. The data of pre- and post-operative self-rated questionnaires are collected and analysed by independent investigators. The data were statistically analysed. A good outcome was defined when the mean score at the ZQ for satisfaction was at maximal 2.0, and the mean improvement of the severity score was at least 0.5, and also for vitality score. For relations between outcome and gender, smoking, BMI, orthopaedic co-morbidity, number of implanted X-Stops were sought. The change in SF-36 scales was related to the outcome. Sixty-five patients did undergo implantation of an X-Stop. The mean age was 64.4 +/- 10.0 years (range: 37.0-85.0 years). 31.1% Of the patients had a good outcome. A good outcome was not related to smoking, BMI, number of implanted X-Stops. However, a good outcome was related to the absence of orthopaedic co-morbidity or male gender. Patients with a good outcome had significantly a better improvement of the scales of the SF-36 concerning physical pain or impairment. The X-Stop does improve the clinical situation. However, a good outcome is achieved less often than previously reported. Probable explanations are discussed.

PMID: 17972111 [PubMed - indexed for MEDLINE]

5. Eur Spine J. 2008 Feb;17(2):188-92. Epub 2007 Sep 11. Links

High failure rate of the interspinous distraction device (X-Stop) for the treatment of lumbar spinal stenosis caused by degenerative spondylolisthesis.

Verhoof OJ, Bron JL, Wapstra FH, van Royen BJ

Department of Orthopaedic Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands.

The X-Stop interspinous distraction device has shown to be an attractive alternative to conventional surgical procedures in the treatment of symptomatic degenerative lumbar spinal stenosis. However, the effectiveness of the X-Stop in symptomatic degenerative lumbar spinal stenosis caused by degenerative spondylolisthesis is not known. A cohort of 12 consecutive patients with symptomatic lumbar spinal stenosis caused by degenerative spondylolisthesis were treated with the X-Stop interspinous distraction device. All patients had low back pain, neurogenic claudication and radiculopathy. Pre-operative radiographs revealed an average slip of 19.6%. MRI of the lumbosacral spine showed a severe stenosis. In ten patients, the X-Stop was placed at the L4-5 level, whereas two patients were treated at both, L3-4 and L4-5 level. The mean follow-up was 30.3 months. In eight patients a complete relief of symptoms was observed post-operatively, whereas the remaining 4 patients experienced no relief of symptoms. Recurrence of pain, neurogenic claudication, and worsening of neurological symptoms was observed in three patients within 24 months. Post-operative radiographs and MRI did not show any changes in the percentage of slip or spinal dimensions. Finally, secondary surgical treatment by decompression with posterolateral fusion was performed in seven patients (58%) within 24 months. In conclusion, the X-Stop interspinous distraction device showed an extremely high failure rate, defined as surgical re-intervention, after short term follow-up in patients with spinal stenosis caused by degenerative spondylolisthesis. We do not recommend the X-Stop for the treatment of spinal stenosis complicating degenerative spondylolisthesis.

PMID: 17846801 [PubMed - indexed for MEDLINE]
PMCID: PMC2226191
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PMID: 16776357 [PubMed - indexed for MEDLINE]