This is a prospective, non-randomized multi-center study to compare the use of Osteocel Plus in subjects who receive ALIF surgery at one or two levels. These subjects will present with degenerative conditions in the lumbar spine that are amenable to surgical treatment and will be screened prior to study enrollment. Subjects will receive Osteocel Plus during their ALIF operation. Subjects will be followed for 24-months following surgery to determine the number of study subjects that are solidly fused at or before 24 months postoperatively, and to determine the mean time to fusion. This data will be compared to published and/or retrospective data for autograft, synthetic ceramics and BMP.