Aspen Spinous Process Fixation System for Use in PLF in Patients With Spondylolisthesis

Study Overview
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Brief Summary
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The purpose of this clinical investigation is to evaluate the clinical outcomes of subject with spondylolisthesis undergoing posterolateral fusion (PLF) surgery utilizing the Aspen™ Spinous Process Fixation System. The Aspen™ device will be evaluated using Oswestry Disability Index (ODI) improvement and success of fusion.

Detailed Description
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Evaluate the clinical outcomes of subject with spondylolisthesis undergoing posterolateral fusion (PLF) surgery utilizing the Aspen™ Spinous Process Fixation System. The Aspen™ device will be evaluated using Oswestry Disability Index (ODI) improvement and success of fusion.

Official Title
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A Multi-Center Prospective Study Evaluation Aspen Spinous Process Fixation System for Use in Posterolateral Fusion (PLF) in Patients With Spondylolisthesis

Conditions
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Spondylolisthesis

Intervention / Treatment
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* Device: Aspen Spinous Process Fixation Device


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 50 and older Diagnosis of mild segmental instability on standing radiography lateral film defined as degenerative spondylolisthesis ≤ 4mm in dynamic imaging (i.e., flexion/extension) Scheduled for an elective single-level posterior decompression and posterolateral fusion using AspenTM spinous process fixation system Oswestry Disability Index (ODI) v 2.1 score >30% Failed at least 3 months of conservative care (non-surgical) OR has clinical signs of neurological deterioration Signed Informed Consent Form Exclusion Criteria: Pre-operative Marked degenerative spondylolisthesis (>4mm) Lesions requiring surgery involving two levels Prior surgery at index level or adjacent level Prior spinal fusion surgery Isthmic or lytic spondylolisthesis Incompetent or missing posterior arch at the affected level (e.g. complete laminectomy, pars defect) Requires complete laminectomy at level of surgery Facet joints at implant level are absent or fractured Vertebral body compromise or acute fracture at implant level Body mass Index (BMI) ≥ 35 Known allergy to titanium Osteoporosis: SCORE (Simple Calculated Osteoporosis Risk Estimation) will be used to screen subjects requiring DEXA. Subjects with T-score < -2.5 will be excluded Paget's disease, osteomalacia, or any other metabolic bone disease Use of medications or any drug known to potentially interfere with bone/soft tissue healing (e.g. chronic systemic steroids) Planned use of additional segmental fixation (eg. facet screws, anterior/lateral plating, anchored cages) Use of Bone Morphogenetic Protein (BMP)* Unlikely to comply with the follow-up evaluation schedule In the opinion of the Investigator, Subject has history of chemical substance dependency or significant psychosocial disturbance that may impact the outcome or study participation Active participation in a clinical trial of another drug or device Active systemic infection or any other health condition that would preclude surgery History of invasive malignancy, except if the subject has received treatment and displayed no clinical signs and symptoms for at least five years Pregnant or planning to become pregnant during study participation Involvement in active litigation related to back problems at the time of screening Direct involvement in the execution of this protocol Pre-existing conditions that could interfere with the evaluation of outcome measures (e.g. musculoskeletal, neuromuscular, etc.) Intra-operative Exclusion Intra-operative visualization of a > 4mm spondylolisthesis not previously noted radiographically Any change in the surgical procedure that violates the inclusion/exclusion criteria. (eg. switching to double level procedure; placing pedicle screws as posterior fixation).

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Aspen Spinous Process Fixation Device<br>The Aspen device provides supplemental posterior fixation for fusion | Device: Aspen Spinous Process Fixation Device<br>* The Aspen device will be placed as posterior fixation to Posterolateral Fusion (PLF)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Absolute change in Oswestry Disability Index (ODI) |  | baseline to 12 months post-operative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Title: Fusion success |  | 12 Months post-operative | 
| Change in Visual Analogue Scale (VAS) (pain) |  | Baseline, 6 weeks, 2 weeks, 3 months, 6 months, 12 months, & 24 months | 
| Neurological status | motor functions, reflexes, and sensory | Baseline, 6 weeks, 3 months, 6 months, 12 months, & 24 months | 
| Operative parameters (estimate blood loss, surgery time, fluoroscopy time, and length of hospital stay) |  | Surgical Visit | 
| Pain medication usage |  | Baseline, surgery, 6 weeks, 3 months, 6 months, 12 months, & 24 months | 
| Change in EQ-5D-3L |  | Baseline, 6 weeks, 3 months, 6 months, 12 months, & 24 months | 
| Change in Zurich Claudication Questionnaire |  | Baseline, 12 months & 24 months |