Clinico-radiological profile of indirect neural decompression using cage or auto graft as interbody construct in posterior lumbar interbody fusion in spondylolisthesis: Which is better

Study design: A prospective clinical study of posterior lumbar interbody fusion in grade I and II degenerative spondylolisthesis was conducted between Mar 2007 and Aug 2008. Purpose: The objective was to assess the clinicoradiological profile of structural v/s nonstructural graft on intervertebral disc height and its consequences on the low back pain (LBP) assessed by Visual analog score (VAS) score and oswestry disability index (ODI) . This study involved 28 patients. Inclusion criteria: Age of 30-70 years, symptomatic patient with disturbed Activities of daily living (ADL), single-level L4/L5 or L5/S1 grade I or grade II degenerative spondylolisthesis. Exclusion criteria: Patients with osteoporosis, recent spondylodiscitis, subchondral sclerosis, visual and cognitive impairment and all other types of spondylolisthesis. All the patients underwent short-segment posterior fixation using CD2 or M8 instrumentation, laminectomy discectomy, reduction and distraction of the involved vertebral space. In 53.5% (n = 15) of the patients, snugly fitted local bone chips were used while in 46.4% (n = 13) of the patients, cage was used. Among the cage group, titanium cage was used in nine (32.1%) and PEEK cages were used in four (14.2%) patients. In one patient, a unilateral PEEK cage was used. The mean follow-up period was 24 months. Among the 28 patients, 67.8% (n = 19) were females and 32.14% (n = 9) were males. 68.24% (n = 18) had L4/L5 and 35.71% (n = 10) had L5/S1 spondylolisthesis. 39.28% (n = 11) were of grade I and 60.71% (n = 17) were of grade II spondylolisthesis. Conclusions: There was a statistically significant correlation (P < 0.012 and P < 0.027) between the change in disc height achieved and the improvement in VAS score in both the graft group and the cage group. The increment in disc height and VAS score was significantly better in the cage group (2 mm +/- SD vis-a-vis 7.2 [88%]) than the graft group (1.2 mm +/- SD vis-a-vis 5 [62 %]).