SUPPLEMENTAL DIGITAL CONTENT
Table, Supplemental Digital Content 1, Study eligibility Key Inclusion Criteria
Age ≥ 45 years
Persistent leg, buttock, or groin pain, with or without back pain, that was relieved by lumbar flexion
Persistently symptomatic with unsuccessful response to at least 6 months of conservative treatment
Moderate spinal stenosis at one or two levels from L1-L5, defined as 25-50%
reduction in lateral/central foraminal diameter compared to adjacent levels, and radiographic evidence of thecal sac and/or cauda equina compression, nerve root impingement, and/or hypertrophic facets with canal encroachment
Zurich Claudication Questionnaire Physical Function score ≥ 2.0
Able to sit for 50 minutes without pain and to walk ≥ 50 feet Key Exclusion Criteria
Fixed motor deficit
Concomitant surgical procedure required
Grade II or greater spondylolisthesis
Unremitting back pain in any spinal position
Significant lumbar instability, defined as ≥ 3 mm translation or ≥ 5 angulation
Active systemic disease that may affect the welfare of the patient
Vertebral osteopenia, osteoporosis, or history of vertebral fracture
Body mass index ≥ 40 kg/m2
Previous lumbar spine surgery
Cauda equine syndrome
Active infection
Pregnant or lactating female
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Figure, Supplemental Digital Content 2, CONSORT flow diagram.
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Table, Supplemental Digital Content 3, Baseline radiographic findings
Variable
Superion n=190
X-Stop n=201 L1-L2
Central stenosis 1.1 0.5
Left lateral stenosis 0.5 0
Right lateral stenosis 0.5 0
Left foraminal stenosis 0.5 0
Right foraminal stenosis 0.5 0 L2-L3
Central stenosis 5.3 5.0
Left lateral stenosis 4.2 4.5
Right lateral stenosis 4.2 5.0 Left foraminal stenosis 3.7 3.0 Right foraminal stenosis 3.7 3.0 L3-L4
Central stenosis 41.6 47.3
Left lateral stenosis 28.4 33.3 Right lateral stenosis 29.5 34.3 Left foraminal stenosis 29.5 30.3 Right foraminal stenosis 27.9 31.8 L4-L5
Central stenosis 77.4 76.6
Left lateral stenosis 52.1 55.7 Right lateral stenosis 52.6 55.7 Left foraminal stenosis 60.0 55.7 Right foraminal stenosis 60.0 55.7
Reported values are percentages. Sum of values > 100% due to more than one diagnosis at each level in some patients.
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Figure, Supplemental Digital Content 4, Changes in Zurich Claudication
Questionnaire over 2 years: a) Symptom Severity, b) Physical Function, and c) Patient Satisfaction.
a.
4
b.
5
c.
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