Abstract
Aim
To investigate the effect of a primary single level TLIF on the lumbar sagittal profile (segmental lordosis and total lumbar lordosis) comparing pre-operative, intra-operative and post-operative radiographs in patients with lumbar spine degenerative disease.
Methods
Patients over the age of 16 who underwent a single-level interbody fusion for degenerative stenosis and/or spondylolisthesis without scoliosis between March 2008 and March 2014 were reviewed. Age, gender, surgical level, surgical approach, facetectomy (unilateral vs bilateral) were recorded. Standardized pre and early and 6 month postoperative upright radiographs as well as an intra-operative lateral radiographs were analyzed for the pelvic incidence (PI), segmental lordosis (SL) at the TILF level and total lumbar lordosis (TL). Data analysis was performed after confirming normality using a paired t-test and is presented as mean (SD). p-value < 0.05 was considered significant.
Results
69 patients were reviewed. The mean age was 58.6 (13.6) years, 39 males (56.5%), a Wiltse approach was used in 30 (43.5%) while 39 had a midline posterior approach. Segments operated were L2/L3 (1 case), L3/L4 (6), L4/L5 (43), L5/S1 (19) and bilateral facetectomy was performed in 13 (18.8%). SL changed from 15.2° (7.3) preoperatively to 20.4° (7.7) intraoperatively (p-value < 0.0001) but measured 17.9° (7.2) (p-value < 0.0001) on early postoperative images and 17.2° (7.3) at 6 months follow up (p-value= 024). The total improvement in SL at 6 months was 2° (6.7), (p-value= 0.001). TL change was insignificant on the early postoperative X-rays (48.5° (12.4) to 47.2° (11.3), p-value= 0.37) but significantly increased to 53.1° (11.5) at six months (p-value < 0.0001) with a total improvement of 4.6° (10) (p-value= 0.001). The mean pelvic incidence was 59.7° (11.2). The cage subsided in 11 (15.9%) cases and we had no metal work loosening.
Conclusion
At the level of the TLIF, much of the lordosis achieved intra-operatively is lost once the patient mobilizes. An improvement in the total lumbar lordosis at 6 months following surgery is likely to be due to the decompression component of the surgical intervention.