Review of Clinical Studies for X-STOP

There are currently only a limited number of relatively short term clinical studies based on small study populations available to evaluate the effectiveness of the X-STOP in long term symptomatic relief.

This article presents a distillation of the clinical trial results available to date, highlighting several areas that have been established and several areas where the results are contradictory and/or not conclusive.

Review of the available studies at the time of this article suggests the following:

• The X-stop procedure is a safe treatment for lumbar spinal stenosis, and the risk of significant surgical complications is small.
• The procedure demonstrated superior relief of symptoms compared to non-operative treatment based on validated outcome measures with post operative follow up between 1 and 4 years. The benefits of the X-STOP procedure were demonstrated in reduction of pain, improved function, and improved quality of life.
• The percent of patients who had the procedure and reported good satisfaction ranges in the 70-78% up to four years after the procedure. Currently, there is no published long term data available for follow up more than 4 years.
• However, some studies report significantly reduced success rates for X-stop treated patients – e.g. less than 50% of patients in the study reported pain relief. This is particularly true for patients in the studies who had spondylolisthesis (slipped vertebra).

• The currently available clinical literature offers a relatively wide range of surgical success rates.
• There are no good studies currently available that directly compare the X-stop procedure to the traditional surgical treatment for spinal stenosis, a decompressive laminectomy (an open decompression). Some of the available studies seem to suggest comparable surgical outcomes in the short term (up to 4 years.)

In addition to knowing about clinical trial success rates, when making a decision about the X-STOP it is important for patients to also talk with their surgeon about the individual surgeon’s success rates in treating patients with similar symptoms and clinical presentation of lumbar stenosis, as results vary both among surgeons and for different clinical situations.

References

1. 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.Eur Spine J. 2008 Feb;17(2):200-3. Epub 2007 Oct 31.
2. 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. Eur Spine J. 2008 Feb;17(2):188-92. Epub 2007 Sep 11.
3. One-year results of X Stop interspinous implant for the treatment of lumbar spinal stenosis. Siddiqui M, Smith FW, Wardlaw D. Spine. 2007 May 20;32(12):1345-8.
4. Quality of life of lumbar stenosis-treated patients in whom the X STOP interspinous device was implanted. Hsu KY, Zucherman JF, Hartjen CA, Mehalic TF, Implicito DA, Martin MJ, Johnson DR 2nd, Skidmore GA, Vessa PP, Dwyer JW, Cauthen JC, Ozuna RM. J Neurosurg Spine. 2006 Dec;5(6):500-7.
5. Interspinous process decompression with the X-STOP device for lumbar spinal stenosis: a 4-year follow-up study. Kondrashov DG, Hannibal M, Hsu KY, Zucherman JF. J Spinal Disord Tech. 2006 Jul;19(5):323-7.

• Article written by:
• Rafael Levin, MD

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