To study the effect of lumbar lordosis change and pelvic parameters on surgical outcomes such as fusion vs. non-fusion (pseudarthrosis), Adjacent Segment Pathology (ASP), and re-operation in patients undergoing 1-, 2- and 3-level PLF. Adult patients with degenerative spine pathologies who had undergone PLF between L2 and L5 levels at an academic center between 2010 and 2020 were included. Pre-operative and early post-operative lateral standing X-Rays of the lumbar spine were used to measure pre-operative lumbar Cobb angle, Postoperative lumbar Cobb angle, pre-operative segmental Cobb angle (measured from the superior endplate of the upper instrumented vertebra to the inferior endplate of the lower instrumented vertebra), postoperative segmental Cobb angle, preoperative pelvic incidence (PI) and pelvic tilt (PT). Change in lumbar and segmental Cobb was calculated as postoperative Cobb angle (lumbar and segmental) minus preoperative Cobb angle. A total of 243 patients met our inclusion and exclusion criterion. Patients who had pseudarthrosis had a significantly less restoration of lumbar lordosis compared to those who did not, both for lumbar cobb angle change (-5.2±8.2 vs. -0.2±8.2; p=0.01) and segmental cobb angle change (-5.4±6.6 vs. -1.5±6.0; p=0.01). Moreover, PI was lower in patients who developed ASP vs. those who didn't. There was no significant difference in these measures (lumbar cobb angle changes and segmental cobb angle change) in patients who experienced ASP and those who did not. Better restoration of lumbar lordosis reduces rates of pseudarthrosis after short-segment PLF but has no association with rates of ASP.
Read full abstract