Surgical Outcomes of Single-Level Transforaminal Lumbar Interbody Fusion for Degenerative Spondylolisthesis With and Without Kyphotic Alignment.

Objective: We sought to investigate the impact of single-level transforaminal lumbar interbody fusion (TLIF) on lumbar sagittal profile in degenerative spondylosis (DS) patients with or without kyphotic alignment, as well as compare radiologic and clinical outcomes based on preoperative sagittal alignment.

Background: DS with a kyphotic alignment at an involved segment constitutes a distinct subgroup. However, previous studies concerning surgical outcomes often lump all patients together without focusing on this distinct subgroup.

Methods: This study reviewed a consecutive series of patients who received single-level TLIF for DS between 2009 and 2016. They were assigned to Groups K and L. All patients were followed up for >2 years. Then demographics and radiographic and clinical outcomes were compared between the groups.

Results: There were 19 and 115 patients in Group K and Group L, respectively. Compared with Group L, Group K was characterized by loss of lumbar lordosis and anterior shifting of L1 axis S1 distance. After surgery, lumbar lordosis and L1 axis S1 distance was significantly improved in Group K, while no significant change occurred in group L. The mean reduction rate was significantly higher in Group K, which had less slippage after surgery, but the differences in slip angle, anterior disk height, and posterior disk height were not significant. The preoperative Oswestry Disability Index and visual analog scale for back pain scores were significantly higher in Group K, while no differences were found in postoperative evaluation.

Conclusions: Despite effective changes radiographic parameters and clinical outcomes, our findings suggest that the 2 groups behave differently in response to single-level TLIF procedure. Reconstruction of lumbar sagittal profile can be achieved in DS with a kyphotic alignment after surgery.