An FDA investigational device exemption study on the Superion interspinous process spacer outcomes compared to X-Stop spacer outcomes was published in Spine.
The study followed patients for two years. The 391 patients were randomly selected to receive the Superion spacer or X-Stop spacer. There were 190 who received the Superion spacer and 201 that received X-Stop at 29 sites across the United States.
The researchers found:
1. The implants were successfully implanted with:
• 99.5 percent of Superion patients
• 99 percent of X-Stop patients
2. The researchers met the composite endpoint of the study demonstrating the Superion spacer was not inferior to the X-Stop spacer.
3. The patients in both groups reported leg pain decreased in severity by 70 percent by two years after surgery. Leg pain was the predominant patient complaint.
4. There were 77 percent of patients who achieved leg pain clinical success after two years and 68 percent who reported back pain clinical success.
5. There were 65 percent of patients who reported Oswestry Disability Index clinical success.
6. Complication rate was similar between both patient groups.
The researchers concluded, "The Superion interspinous process spacer relieves symptoms of intermittent neurologic claudication secondary to moderate LSS in the majority of patients through two years."