Predicting Immediate Lordosis Restoration After Anterior Lumbar Interbody Fusion and the Effect of Posterior Column Osteotomies.

ABSTRACT

OBJECTIVE: Anterior lumbar interbody fusion (ALIF) can be combined with posterior column osteotomies (PCOs) to maximize lordotic correction. This study compares radiographic changes in regional and segmental lordosis in patients undergoing ALIF with and without PCOs. METHODS: Patients >18 years old who underwent ALIF at 1 or 2 segments at a single institution (January 2014-July 2020) were included. Preoperative and postoperative radiographic parameters were determined, and a propensity-matched analysis was performed. RESULTS: Ninety-nine patients (53 [54%] men) underwent ALIF at 129 levels (mean [SD], 1.3 [0.46] levels; median [range] age, 61 [32-83] years). PCOs were performed in 13 (13%) patients at 19 (15%) segments. PCOs included 13 Schwab grade 1 and 6 grade 2 osteotomies. All measures, including lumbar lordosis, segmental lordosis, disc angle, and neural foramen height, increased significantly after surgery (P ≤ 0.003). In the propensity-matched analysis, PCO was associated with greater increases in lumbar lordosis (14.9° vs. 8.2°, P = 0.02), segmental lordosis (14.0° vs. 9.6°, P = 0.03), and disc angle (15.0° vs. 10.2°, P = 0.046). The change in disc angle more closely approximated the inherent lordosis of the cage when PCO was performed (94% vs. 62%, P = 0.004). CONCLUSIONS: Performing PCOs and ALIFs significantly increased the radiographic correction of overall and segmental lordosis in the selected patient cohort. The disc angle achieved with ALIF without PCOs was approximately 60% of the cage lordosis. The addition of PCO allowed for greater segmental compression, enabling the disc angle to reach nearly 100% of the inherent interbody cage lordosis.