X-STOP® for the Treatment of Lumbar Spinal Stenosis

The X-STOP® IPD® spacer fits between two bones in the lower spine, called spinous processes, to limit spinal movement or extension that causes painful pinching of spinal nerves.

Image courtesy of Kyphon Inc.

The X-STOP® Interspinous Process Decompression (IPD®) System is a titanium alloy metal spacer that is surgically implanted between the vertebrae to alleviate symptoms of lumbar spinal stenosis.

Lumbar spinal stenosis (LSS) is a narrowing of the spinal canal, which results in pinching of the spinal cord and nerves. This causes numbness, weakness, cramping or pain in the legs, feet or buttocks upon walking or standing. Symptoms of LSS are relieved by sitting, or bending forward while walking.

Surgical Procedure

The X-STOP® device is inserted by an orthopedic surgeon, or neurosurgeon, through a two- to five-centimetre incision. The procedure takes less than one hour, and is typically performed under local anesthesia.[1]

Who Might Benefit?

LSS is associated with age-related disc degeneration and osteoarthritis of the spine; therefore, the prevalence is expected to increase with an aging population.[1]

The X-STOP device is indicated for patients 50 years or older who have LSS that has not responded to at least six months of treatment with physical therapy, analgesics, non-steroidal anti-inflammatory drugs, and intraspinal steroid injections.[1] X-STOP may be an alternative treatment to more invasive surgeries, such as laminectomy, where the spinal canal is decompressed by removing bone and tissue.

Regulatory Status

The X-STOP Interspinous Process Decompression (IPD) System (Kyphon Inc., Sunnyvale, CA) was approved for marketing in Europe and Japan in 2001, and by the US Food and Drug Administration (FDA) in November of 2005.[1] Health Canada licensing has not yet been sought.

Evidence

A prospective, randomized controlled trial reported improved clinical symptoms and physical function in 100 patients who received X-STOP implants, compared with 91 control patients who received medical therapy.[2-4] Outcomes were reported as changes in the Zurich Claudication Questionnaire, which measures symptom severity, physical function, and post-treatment patient satisfaction. At two-year follow-up, there was a mean improvement of 45.4% in the symptom severity score over baseline in the X-STOP group, compared with a 7.4% improvement in the control group (p<0.001). The mean improvement in the physical function score was 44.3% in the X-STOP group, whereas scores in the control group deteriorated by 0.4% (p<0.001). In the X-STOP group, 73.1% of patients were satisfied with the treatment compared with 35.9% of control patients (p<0.001).[3]

Six patients (6%) in the X-STOP group and 24 patients (26%) in the control group underwent decompressive laminectomy surgery for unresolved symptoms during the two-year follow-up period.[3]

Cost

In the United States, the list price for each X-STOP is US$5,500.[1] An X-STOP spacer may be implanted at one or two lumbar levels.[1]

References

[1] Interspinous process decompression to treat spinal stenosis. [Target database]. Plymouth Meeting (PA): ECRI; 2006.

[2] Zucherman JF, et al. Eur Spine J 2004;13(1):22-31.

[3] Zucherman JF, et al. Spine 2005;30(12):1351-8.

[4] Kondrashov DG, et al. J Spinal Disord Tech 2006;19(5):323-7.