A Comparative Study Between Posterolateral Lumbar Fusion and Transforaminal Lumbar Interbody Fusion for Degenerative Lumbar Spondylolisthesis

Introduction Degenerative spondylolisthesis (DS) is a degenerative condition characterized by subluxation of one vertebral body anterior to the adjacent inferior vertebral body with an intact pars. Conservative treatment approaches, such as steroid injections and physical therapy, may work well at first, but in resistant situations, surgery is frequently necessary. Posterolateral lumbar fusion (PLF) has been widely used, but transforaminal lumbar interbody fusion (TLIF) offers theoretical advantages such as improved alignment and enhanced fusion rates. Methods This retrospective study examined patients with DS who underwent PLF or TLIF at R.L. Jalappa Hospital and Research Centre, Kolar, Karnataka, India, between January 2020 and January 2024. The inclusion criteria were planned one- or two-level fusion DS resistant to conservative treatment and at least one year of follow-up. Patients with prior lumbar fusion or uncontrolled comorbidities were not included. Details were taken from medical records and Picture Archiving and Communication System (PACS), and SPSS Version 22 was used for analysis. Continuous variables were compared using t-tests or Mann-Whitney U tests, and categorical variables were compared using chi-square tests. The non-inferiority of TLIF to PLF was assessed with predefined margins. The study included 56 patients (28 in each group), with outcomes measured via visual analogue scale (VAS), 12-Item Short Form Survey (SF-12) scores, and radiological outcomes. The threshold for clinical significance was p < 0.05. Results This research compared TLIF and PLF in a total of 56 DS patients. Demographic data, operative details, and pre-surgical parameters showed no significant differences. Clinical outcomes revealed comparable improvements in scores for leg and back pain (p > 0.05). SF-12 Physical Component Summary (PCS) scores were significantly higher post-surgery in the TLIF group (42.4 ± 5.1) compared to the PLF group (37.9 ± 4.5) (p = 0.01). Radiologically, the slippage was significantly lower in the TLIF cohort (2.1 ± 1.02) compared to the PLF cohort (3.1 ± 1.9) (p = 0.01). Both anterior and posterior disc heights were substantially increased in the TLIF group (11.3 ± 1.6 vs. 9.3 ± 1.5 in PLF unit, p < 0.01) compared to the PLF group (1.7 ± 0.9 vs. 0.8 ± 0.4, p < 0.01). There were no discernible variations in lumbar lordosis, sacral slope, or changes in the tilt of the pelvis. TLIF demonstrated better radiographic improvements but had clinical outcomes similar to those of PLF. Conclusion TLIF demonstrated superior radiographic improvements, particularly in disc height and slippage reduction, while clinical outcomes were comparable between TLIF and PLF, suggesting that both are effective options for managing DS.