Proximal Junctional Failure Development Despite Achieving Ideal Sagittal Correction According to Age-Adjusted Alignment Target in Patients With Adult Spinal Deformity: Risk Factor Analysis of 196 Cases Undergoing Low Thoracic to Pelvic Fusion.

OBJECTIVE

To identify the risk factors for proximal junctional failure (PJF) after adult spinal deformity (ASD) surgery despite ideal sagittal correction according to age-adjusted alignment target.

METHODS

The study included patients who underwent low thoracic to pelvic fusion for ASD and obtained ideal correction according to age-adjusted pelvic incidence minus lumbar lordosis. PJF was defined either radiographically as a proximal junctional angle (PJA) of >28° plus a difference in PJA of >22° or clinically as revision surgery for proximal junctional complications. Clinical and radiographic variables were assessed to identify the risk factors for PJF.

RESULTS

The final study cohort consisted of 196 patients, of whom 170 were women (86.7%), with an average age of 68.3 years. During mean follow-up duration of 45.9 months, PJF occurred in 43 patients (21.9%). Multivariate logistic regression analysis revealed that old age (odds ratio [OR], 1.063; 95% confidence interval [CI], 1.001-1.129; p=0.046), large preoperative sagittal vertical axis (OR, 1.007; 95% CI, 1.001-1.013; p=0.024), nonuse of a transverse process (TP) hook (OR, 5.556; 95% CI, 1.205-19.621; p=0.028), and high lumbar distribution index (LDI) (OR, 1.136; 95% CI, 1.109-1.164; p<0.001) were significant risk factors for PJF development.

CONCLUSION

A sizeable proportion of patients (21.9%) developed PJF despite achieving ideal sagittal correction. Using TP hooks with avoiding excessive LDI can be helpful to further mitigate the risk of PJF development in this patient group.