Superion(®) InterSpinous Spacer for treatment of moderate degenerative lumbar spinal stenosis: durable three-year results of a randomized controlled trial.

PURPOSE: This report provides the 3-year clinical outcomes from the randomized, controlled US Food and Drug Administration Investigational Device Exemption trial of the Superion(®) for the treatment of moderate degenerative lumbar spinal stenosis. PATIENTS AND METHODS: The Superion(®) was evaluated in the treatment of subjects aged 45 years or older suffering from symptoms of intermittent neurogenic claudication, secondary to a confirmed diagnosis of moderate degenerative lumbar spinal stenosis at one or two contiguous levels from L1 to L5. Patients were treated between June 2008 and December 2011 at 31 investigational sites. Three hundred ninety-one subjects were included in the randomized study group consisting of 190 Superion(®) and 201 X-STOP(®) control subjects. The primary composite endpoint was individual patient success based on four components: improvement in two of three domains of the Zurich Claudication Questionnaire, no reoperations at the index level, no major implant/procedure-related complications, and no clinically significant confounding treatments. RESULTS: At 3 years, the proportion of subjects achieving the primary composite endpoint was greater for Superion(®) (63/120, 52.5%) than for X-STOP(®) (49/129, 38.0%) (P=0.023) and the corresponding success rates exceeded 80% for each of the individual components of the primary endpoint in the Superion(®) group (range: 81%-91%). Improvements in back and leg pain severity as well as back- and disease-specific functional outcomes were also maintained through 36 months. CONCLUSION: The 3-year outcomes from this randomized controlled trial demonstrate durable clinical improvement consistently across all clinical outcomes for the Superion(®) in the treatment of patients with moderate degenerative lumbar spinal stenosis.

Superion interspinous process spacer for intermittent neurogenic claudication secondary to moderate lumbar spinal stenosis: two-year results from a randomized controlled FDA-IDE pivotal trial.

STUDY DESIGN: Prospective, multicenter, randomized, controlled, investigational device exemption noninferiority trial. OBJECTIVE: To determine 2-year outcomes in patients with intermittent neurogenic claudication secondary to moderate lumbar spinal stenosis (LSS) who were treated with the Superion interspinous process spacer. SUMMARY OF BACKGROUND DATA: Interspinous spacers are a less-invasive treatment alternative compared with surgical decompression for patients with LSS unresponsive to conservative care. High-quality comparative data with these devices are lacking. METHODS: Patients presenting with intermittent neurogenic claudication secondary to moderate LSS who failed at least 6 months of nonsurgical management were randomly allocated to treatment with the Superion spacer or a control spacer (X-Stop) and followed for 2 years. RESULTS: A total of 391 randomized patients were implanted with Superion (n = 190) or control (n = 201) spacers at 29 sites in the United States between August 2008 and December 2011. Implants were successfully implanted in 99.5% of patients with Superion and 99.0% of control patients. The primary composite endpoint of this study was met, which demonstrated that the Superion spacer was noninferior to the X-Stop spacer. Leg pain, the predominant patient complaint, decreased in severity by 70% during 2 years in each group. Most (77%) patients achieved leg pain clinical success (improvement ≥20 mm) at 2 years. Back pain clinical success (improvement ≥20 mm) was 68%, with no differences between groups. Oswestry Disability Index clinical success (≥15% point improvement) was achieved in 65% of patients. The rates of complications and reoperations were similar between groups. CONCLUSION: The Superion interspinous process spacer relieves symptoms of intermittent neurogenic claudication secondary to moderate LSS in the majority of patients through 2 years. LEVEL OF EVIDENCE: 2.

Two-year clinical outcomes of a multicenter randomized controlled trial comparing two interspinous spacers for treatment of moderate lumbar spinal stenosis.

BACKGROUND: Interspinous spacers are a minimally invasive surgical alternative for patients with lumbar spinal stenosis (LSS) unresponsive to conservative care. The purpose of this prospective, multicenter, randomized, controlled trial was to compare 2-year clinical outcomes in patients with moderate LSS treated with the Superion(®) (Experimental) or the X-Stop(®), a FDA-approved interspinous spacer (Control). METHODS: A total of 250 patients with moderate LSS unresponsive to conservative care were randomly allocated to treatment with the Experimental (n = 123) or Control (n = 127) interspinous spacer and followed through 2 years post-treatment. Complication data were available for all patients and patient-reported outcomes were available for 192 patients (101 Experimental, 91 Control) at 2 years. RESULTS: Zurich Claudication Questionnaire (ZCQ) Symptom Severity and Physical Function scores improved 34% to 36% in both groups through 2 years (all p < 0.001). Patient Satisfaction scores at 2 years were 1.8 ± 0.9 with Experimental and 1.6 ± 0.8 with Control. Axial pain decreased from 59 ± 26 mm at baseline to 21 ± 26 mm at 2 years with Experimental and from 55 ± 26 mm to 21 ± 25 mm with Control (both p < 0.001). Extremity pain decreased from 67 ± 24 mm to 14 ± 22 mm at 2 years with Experimental and from 63 ± 24 mm to 18 ± 23 mm with Control (both p < 0.001). Back function assessed with the Oswestry Disability Index similarly improved with Experimental (37 ± 12% to 18 ± 16%) and Control (39 ± 12% to 20 ± 16%) (both p < 0.001). Freedom from reoperation at the index level was 84% for Experimental and 83% for Control (log-rank: p = 0.38) at 2 years. CONCLUSIONS: Both interspinous spacers effectively alleviated pain and improved back function to a similar degree through 2 years in patients with moderate LSS who were unresponsive to conservative care. TRIAL REGISTRATION: NCT00692276.