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


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.


CONCLUSIONS
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.
The Spine Center, University of Colorado Hospital, Denver, CO, USA.
Vikas V
VV
Patel
Spine Institute of Louisiana, Shreveport, LA, USA.
Pierce D
PD
Nunley
Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT, USA.
Peter G
PG
Whang
Performance Spine and Sports Physicians, PC, Pottstown, PA, USA.
Thomas R
TR
Haley
Texas Back Institute, Denton, TX, USA.
W Daniel
WD
Bradley
Department of Neurological Surgery, Stony Brook Medicine, Stony Brook, NY, USA.
Raphael P
RP
Davis
Jon Block, Ph.D. San Francisco, CA, USA.
Jon E
JE
Block
McLaren Hospital, Petoskey, MI, USA.
Fred H
FH
Geisler
InterSpinous Spacer; Superion®; lumbar spinal stenosis; neurogenic claudication