Objectives: To assess the clinical, functional and radiological outcome of posterior lumbar interbody fusion (PLIF) by Banana cage with bone graft.

Material and Methods: This retrospective analytical study was carried out in spine unit of Orthopaedic surgery department of Bangabandhu Sheikh Mujib medical University, and another private hospital in Dhaka city, Bangladesh from January 2010 to December 2020. We did PLIF by Banana cage with bone graft for High-grade Lumbar Spondylolisthesis at L5-S1. The follow up period ranges from 1 year to 2 years (average 18 months). Within these follow up period we have assessed the patients clinically, functionally and radiologically. All patients were assessed by Visual Analogue Score (VAS), Oswestry Disability Index (ODI), Waddell disability index (WDI), Spino-pelvic parameters, Modified Macnab’s Criteria to find out overall outcome and Hackenberge ctriteria for radiological fusion.

Results: Total 40 patients were included among them 16were male and 24 were female. The average age of the patients was 52.45 ±10.1 years. Maximum (60.0%) patients were housewife followed by 20.0%, 10.0%, 10% were day laborer, farmer and service holder respectively. Average pelvic tilt was 26.05 ± 6.27° preoperatively and 24.10 ± 6.26° at the final follow-up, average PI was 66.07 ± 7.39° preoperatively and 61.19 ± 7.08° at the final follow-up. Preoperative lumbar lordosis was 45.55 ± 6.71° with postoperatively 37.29 ± 6.19°at final follow-up. VAS score and ODI scales were improved significantly from preoperative 6.90 ± 6.16 and 57.60 ± 15.66, respectively, to postoperatively and final follow-up 2.0 ± 0.8 and 7.60 ± 2.40, respectively. Pre-operative Translation ratio, slip angle and disc height ratio were 21.96 ± 10.25, -18.87 ± 8.28, 11.03 ± 4.36 respectively and postoperatively 13.17 ± 6.57, -18.44 ± 7.12, 19.60 ± 3.36 respectively. Fusion was achieved in 36 cases (90%), 3 cases (7.5%) were fragmented and pseudoarthrosis showed only 1 case (2.5%). Most of the study population according to post operative clinical outcome showed excellent outcome (95%), 1 (2.5%) case had good and 1 (2.5%) case had fair outcome.

Conclusion: It can be concluded that, posterior lumbar interbody fusion (PLIF) by Banana cage with bone graft can be a very good option for the treatment of High-grade Lumbar Spondylolisthesis at L5-S1 levels.