Revision Surgery for Proximal Junctional Failure: A Single-Center Analysis of 1180 Adult Spinal Deformity Patients with Long-Term Follow-Up

Introduction: Proximal junctional failure (PJF) represents PJK with structural failure and/or mechanical instability. This study aims to report the incidence of PJF and recurrent PJF in ASD patients in a large single institution experience after instrumented fusion to the pelvis. Revision strategies and mechanisms of failure are examined.

Methods: A single-center retrospective review was performed for ASD patients who underwent revision surgery for PJF after posterior instrumented fusion to the pelvis. Patients were stratified into upper thoracic (UT, 10 patients, T2-T6), lower thoracic (LT, 35 patients, T8-T11), and lumbar spine (L, 9 patients, L1-L3) UIV groups.

Results: In 1180 patients, 54 (4.6%) developed PJF and underwent revision (mean age 65.0±6.8 years, 59.3% female, mean BMI 30.3±5.9 kg/m2). Average follow-up after revision was 3.1±2.0 years. Mechanisms of PJF for each group were vertebral fracture (UT: 30.0%, LT: 62.9%, L: 55.6%, P=0.183), soft-tissue disruption (UT: 50.0%, LT: 20.0%, L: 11.1%, P=0.089), and screw pullout (UT: 20.0%, LT: 17.1%, L: 33.3%, P=0.561). Of those in the UT group, 40.0% of patients had a new UIV after revision that crossed the cervicothoracic junction (mean extension of fusion 7.5 ± 3.3 levels, most commonly to C2: 75.0%) and 60.0% of patients did not (mean extension of fusion 2.5 ± 0.8 levels, most commonly to T2: 66.7%). For the LT group, 91.4% of patients had a revision into the UT spine (mean extension of fusion 6.0 ± 1.6 levels, most commonly to T3: 28.6% and T4: 25.7%). Regarding patients in the L group, 88.9% of them were revised to the LT spine (mean extension of fusion 4.6 ± 1.9 levels, most commonly to T10: 44.4%). Twenty-six patients (48.1%) required a second revision surgery (18.7±15.2 months) after their first. From the patients that were revised again, 16 patients (27.8%) were revised for new-onset PJF above the post-revision UIV. Patient-specific and radiographic risk factors in the development of recurrent PJF could not be elucidated.

Conclusion : 4.6% of patients developed PJF after long segment fusions for ASD. Recurrent PJF was the most common complication after revision surgery. There were no identifiable risk factors for recurrent PJF suggesting a complex relationship with preoperative patient characteristics.