X-STOP for Spinal Stenosis: Research
As part of the FDA approval process, a multi-center, prospective, randomized controlled study was conducted in which 191 subjects were enrolled and treated at 9 centers. Control group treatment consisted of continued non-operative therapy, (e.g. use of bed rest, a lumbar corset, and varied number of epidural steroid injections). In both groups, NSAIDs, analgesics, and physical therapy were prescribed as needed. There was no statistical difference in the amount of analgesics used by both groups during the 24 month period. Patients must have already had at least 6 months of non-operative treatment in both groups, without symptom relief. Success was measured as a combination of symptom relief, functional improvement, and patient satisfaction.
The X-STOP was implanted in 100 subjects, compared to 91 control subjects who were treated with continued non-operative therapy. In the study submitted to the FDA, here were the results:
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47% in the X-STOP group achieved an overall successful outcome, measured in terms of pain relief and ability to function (this drops to 37% if one of the nine investigating sites that had much better outcomes than the other 8 is excluded)
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5% in the control group of continued non-operative care achieved overall successful outcome (or 3%, excluding the one investigating site that had much better outcomes than the others)
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Six X-STOP patients and 24 non-operative patients underwent a laminectomy for continued spinal stenosis symptoms during the course of the study, based on a determination made by the individual physician and patient.
In 10 to 15% of the X-STOP treated patients who initially improved, lumbar spinal stenosis symptoms returned during the course of the study. Other complications in the study include:
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One patient died after congestive heart failure complications following the X-STOP surgery
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Four X-STOP implant patients had re-operations: 3 for wound-related issues, and 1 implant was removed after it dislodged subsequent to a fall
Comparing X-STOP to other treatments and surgeries
Although the X-STOP device has helped relieve pain and improve function in many lumbar spinal stenosis patients, many surgeons believe that decompression, possibly including fusion, remains the gold standard for foraminal or central spinal stenosis at a single or even multiple levels. Other reasons that some surgeons do not use the X-STOP include:
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The devices do not directly address the underlying spinal pathology
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Many spinal stenosis patients have multiple-level disease and elements of spinal instability and thus are not good candidates for use of the X-STOP
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The device forces a patient’s already degenerative and flattened lumbar spine into further focal kyphosis, which is thought to add further stress to the lower back
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Payment may be an issue since Medicare does not clearly reimburse facilities and surgeons for their costs in implanting this device
Although it might not be the best or only treatment approach for patients with lumbar spinal stenosis, the X-STOP represents another option for subset of spinal stenosis patients. Similar devices may soon be available. Reimbursement issues continue to be argued with insurance carriers, including Medicare (CMS).