Abstract
Objective: Lateral lumbar interbody fusion (LIF) has been widely used in adult spinal deformity (ASD) surgery. However, anterior longitudinal ligament rupture (ALLR) has been occasionally identified following posterior spinal correction surgery. This study aimed to assess the incidence of ALLR and to identify the risk factors of ALLR in patients with ASD.
Materials and Methods: This study included 43 consecutive patients (8 male and 35 female patients) who underwent posterior corrective surgery involving LIF (128 levels) for ASD between 2014 and 2018. The patients' mean age was 72±7 years, and the minimum follow-up period was 1 year. Following LIF, posterior correction and fusion surgery using the cantilever technique was performed. Oblique LIF was performed in 27 patients, whereas extreme lateral interbody fusion (XLIF) was performed in 16 patients. The mean number of spinal fused levels was 8.9±1.8 (range: 8-15), and the mean number of LIF levels was 3±0.6 (range: 2-4). ALLR was considered if an LIF cage showed no contact with the vertebral endplates. The radiographic parameters included thoracic kyphosis, lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt, and sagittal vertical axis.
Results: ALLR occurred in 10 patients (22%) and at 11 levels (8.6%). XLIF and preexisting osteoporotic vertebral fracture were identified as independent risk factors of ALLR. LL change was approximately 10 degrees greater in the ALLR group than in the non-ALLR group (P = 0.017), and overcorrection was observed in the ALLR group (PI-LL: −7.9±7 degrees). Segmental lordotic angle change at the ALLR level was much larger than after LIF and correction surgery. ALLR-related reoperation was performed in two cases (decompression surgery because of posterior impingement and rod breakage).
Conclusions: ALLR occurred in 10 patients (22%), and XLIF use and preexisting osteoporotic vertebral fracture were independent risk factors of ALLR. Moreover, overcorrection was observed in patients with ALLR. Care should be taken to avoid ALLR, which may require additional surgery.
