Objective:

Lower back pain associated with degenerative disc disease (DDD) is a leading cause of disability worldwide. ALIF has been shown to be effective for treating refractory DDD, but it remains unclear which patients may benefit most from the procedure. This study aims to develop a predictive model for clinical success in L5/S1 ALIF for DDD.

Methods:

A retrospective cohort study of 68 patients with refractory DDD who underwent L5/S1 ALIF was performed. Clinical success was defined as an improvement in Oswestry Disability Index (ODI) of 20 points postoperatively. Exploratory analyses were performed on 16 preoperative clinical and radiographic parameters, followed by a multivariate logistic regression. Evaluation of the predictive model was performed.

Results:

Following exploratory analyses, 4 parameters were suitable for inclusion in the multivariate model. Workers’ compensation (WC) status (OR 0.02 (95% CI: 0.001-0.262) p=0.004) and preoperative ODI (OR 1.13 (95% CI: 1.05-1.23) p=0.002) were statistically significant parameters. Furthermore, posterior disc height (PDH) and disc diameter (DD) contributed significantly to the model variance (OR 0.69 (95% CI: 0.44-1.09); OR 0.97 (95% CI: 0.81-1.15) respectively). The model had a sensitivity of 81.5%, specificity of 83.3%, c-statistic of 0.921 and a calibration plot similar to the 45° reference line.

Conclusions:

This analysis confirms WC and low preoperative ODI as risk factors for successful L5/S1 ALIF performed for DDD. It also identifies novel prognostic factors, namely PDH and DD. This model can aid in patient counselling and selection in the management of L5/S1 DDD.