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

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