Transforaminal lumbar interbody fusion in treating degenerative spondylolisthesis at L 4 with kyphotic versus non-kyphotic angulation

Abstract

Objective To compare the radiographic and clinical results of transforaminal lumbar interbody fusion(TLIF) in the treatment of degenerative spondylolisthesis (DS) with or without kyphotic angulation. Methods This study retrospectively reviewed a consecutive cohort of 137 patients with L4 DS (Meyerding grade I or II) who received TLIF between January 2009 and December 2012 and had a minimum follow-up of 2 years, including 24 males and 113 females, with the average age of 59.1±11.6 years (45-72 years) . The enrolled patients were divided into two groups based on the angulation of intervertebral space: the kyphotic group and the non-kyphotic group. Slip angle (SA), anterior disc height (ADH), posterior disc height (PDH), slip percentage (SP) and segmental kyphosis (SK) was measured to evaluate the radiographic outcomes. Oswestry disability index (ODI) and visual analogue scale (VAS) was collected to evaluate the clinical results. The radiographic measurements and clinical indexes were recorded before and after surgery and at latest follow-up. The independent samples t test was performed to analyze the differences between the two groups in terms of radiographic and clinical outcomes. Results Kyphotic slip was observed in 21(15.3%) patients, while non-kyphotic slip in 116 (84.7%) patients. No significant difference was observed in terms of age, gender, operation time and blood loss between the two groups. The preoperative SA in kyphotic and non-kyphotic group was 3.1°±2.3° and -8.2°±4.7°, respectively. The kyphotic group had significantly lower ADH and higher PDH than the non-kyphotic group, while there was no significant difference in SP between the two groups. After surgery, the postoperative and latest follow up radiographic results showed that patients of both groups had significant improvement, without significant differences between groups in terms of ADH, PDH, SA and SK, but the reduction of slip was significantly higher in the kyphotic group. Postoperative and follow-up ODI and VAS scores demonstrated remarkable improvement after surgery, without difference between groups, despite being higher in the kyphotic group than the non-kyphotic group preoperatively. Conclusion The kyphotic angulation of intervertebral space benefits to and facilitates slip reduction for L 4 DS via TLIF procedure, and achieves improvements in life quality which is similar to the nonkyphotic group. Key words: Lumbar vertebrae; Intervertebral disc degeneration; Spondylolysis; Spinal fusion; Quality of life