Physical Capability Outcomes After Single-Level PD-L vs Single-Level ALIF: a Multi-Center Clinical Trial

Inclusion Criteria: Eligible patients will meet the following criteria based on clinically appropriate criteria per standard of care at individual institutions which may include but are not limited to * skeletally mature; BMI \< 40 * suffered from low-back pain with or without leg pain for 6 months or longer * no evidence of spinal deformity on plain radiograph * no evidence of angular instability on flexion extension radiographs * severe and incapacitating low-back pain, defined as a score of 40% or greater on the Oswestry Disability Questionnaire * a single level of degenerative disc disease at L34, L45, or L5-S1 on magnetic resonance imaging (MRI) scan * discography, if indicated, reproduces pain at the level of degeneration noted on the MRI scan and is negative for pain reproduction at adjacent levels * bone mineral density T-Score by DEXA Scan \>-1.0 for any skeletal region * computed tomographic (CT) scan demonstrates the absence of pars defect at the index level * CT scan demonstrates the absence of significant facet arthropathy at the index level * considered reasonable candidates for surgery in regard to psychological factors as determined according to the standard of care at each participating center Exclusion Criteria: * active systemic infection * evidence of alcoholism * spondylolisthesis of greater than grade 1 * clinically significant lumbar spinal stenosis * allergy to implant materials * isolated radicular syndrome * vertebral body compromised by trauma at the index level.