Introduction: The spinopelvic balance of a normal population and normal ranges are well described in the literature. There is also evidence that certain degenerative conditions can lead to a preponderance of loss of lordosis at specific spinal levels. There is limited literature on the range and magnitude of loss of lordosis for known degenerative lumbar spine pathologies. We aimed to establish whether common degenerative lumbar spine conditions have a predictable sagittal profile and associated range of lordosis.
Methods: A retrospective analysis of a dual surgeon database was performed and imaging analysed for spinopelvic parameters. Degenerative conditions studied were; Lumbar degenerative spondylolisthesis (L3/4 and L4/5 analysed separately), L5/S1 degenerative disc disease, L5/S1 isthmic spondylolisthesis. Pelvic incidence, sacral slope, Pelvic tilt, segmental and global lumbar lordosis, vertebral lordosis and lumbar vertical axis were measured.
Results: The range of change in segmental lordosis was normally distributed for all studied degenerative spinal conditions except L5/S1 isthmic spondylolisthesis. L5/S1 degenerative disc disease affected younger adults (mean age 37) whilst degenerative spondylolisthesis at L3/4 and L4/5 affected older adults (mean ages 69.5 and 68.9 respectively). Removing an outlying high grade L5/S1 isthmic spondylolisthesis made the data distribution approach a normal distribution.
Discussion: Most degenerative spinal pathologies cause a normally distributed spectrum of deformity which should be addressed and corrected with a tailored, individualised surgical plan for each patient. Universal treatment recommendations should be interpreted with caution.