Efficacy of the Aspen Spinous Process System in Anterior Lumbar Interbody Fusion (ALIF)

Inclusion Criteria:

• Age between 18 and 75 years
• Scheduled for an elective single level ALIF with posterior fixation
• Diagnosis of primary symptomatic DDD confirmed with appropriate imaging studies and/or positive lumbar discography
• Oswestry Disability Index (ODI) v 2.1 score >30%
• Failed at least 6 weeks of conservative care (non-surgical)/clinical signs of neurological deterioration
• No contraindications for ASPEN spinous process system (at the discretion of the investigator)

Exclusion Criteria:

• Prior lumbar fusion surgery at any level (prior discectomy and/or laminectomy allowed)
• Spondylolisthesis grade 3 or more
• Lytic spondylolisthesis
• Incompetent or missing posterior arch at the affected level (e.g. laminectomy, pars defect)
• Currently requires laminectomy at level of surgery
• Facet joints at implant level are absent or fractured
• Post-traumatic vertebral body compromise or acute fracture at implant level
• Body mass Index (BMI) > 40
• Known allergy to titanium
• Osteoporosis: SCORE (Simple Calculated Osteoporosis Risk Estimation) will be used to screen subjects who require 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 Bone Morphogenetic Protein (BMP)
• Unlikely to comply with the follow-up evaluation schedule
• Subject has recent history (less than 3 years) of chemical substance dependency or significant psychosocial disturbance that may impact the outcome or study participation
• Participation in a clinical trial of another investigational drug or device within the past 30 days
• Systemic infection such as AIDS, HIV, and active hepatitis
• Active malignancy defined as 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 the length of study participation
• Involvement in active litigation related to back problems at the time of screening
• Direct involvement in the execution of this protocol