Effect of the Posterior Ligamentous Complex on the Adjacent Segments Degeneration After Lumbar Surgery

Purpose: To investigate whether destroying the adjacent posterior ligamentous complex (PLC) has an effect on adjacent segment degeneration (ASD) after L5/S1 posterior lumbar interbody fusion (PLIF).

Methods: This retrospective study was performed in patients who received L5/S1 PLIF with pedicle screw instrumentation for lumbar spinal stenosis with or without isthmic spondylolisthesis. They were divided into the total laminectomy group, which had destruction of the PLC of the adjacent segment, or partial laminectomy group, which did not. Vertebral slip, osteophytes, disk height, and range of motion were examined by plain radiography, and thickness of the ligamentum flavum (LF) and anteroposterior diameters of the lumbar vertebral body and spinal canal were assessed by magnetic resonance imaging (MRI). Disc degeneration and spinal stenosis on MRI scans were categorized. The incidence of ASD and clinical outcome were compared between the groups.