This study investigated the incidence and risk factors of rod fracture (RF) after multiple-rod constructs (MRCs) for adult spinal deformity (ASD) surgery.
A single-center, single-surgeon consecutive series of adult patients who underwent posterior thoracolumbar fusion at 4 or more levels using MRCs after osteotomy with at least 1 year of follow-up were retrospectively reviewed. Patient characteristics, radiological parameters, operative data, and clinical outcomes (on the Scoliosis Research Society-22r questionnaire) were analyzed at baseline and follow-up.
Seventy-six patients were enrolled in this study. RF occurred in 9 patients (11.8%), with all cases involving partial rod breakage. Seven patients (9.2%) underwent revision surgery. There were no significant differences in baseline demographic characteristics, radiological parameters, and surgical factors between the RF and non-RF groups. Multivariable analysis revealed that interbody fusion at the L5–S1 and L4–S1 levels could significantly reduce the occurrence of RF after MRCs for ASD (adjusted odds ratios 0.070 and 0.035, respectively). The RF group had significantly worse function score (mean 2.9 ± 0.8 vs 3.5 ± 0.7) and pain score (mean 2.8 ± 1.0 vs 3.5 ± 0.8) compared with the non-RF group at last visit.
RF occurred in 11.8% of patients with MRCs after ASD surgery. Most RFs occurred at the lumbosacral junction or adjacent level (77%). Interbody fusion at the lumbosacral junction (L5–S1 or L4–S1 level) could significantly prevent the occurrence of RF after MRCs for ASD.