Prevention of Acute Proximal Junctional Fractures After Long Thoracolumbar Posterior Fusions for Adult Spinal Deformity Using 2-level Cement Augmentation at the Upper Instrumented Vertebra and the Vertebra 1 Level Proximal to the Upper Instrumented Vertebra.

STUDY
DESIGN: Retrospective cohort analysis.
OBJECTIVE: To evaluate efficacy of proximal junction fracture (PJF) prevention in adult spinal deformity (ASD) using 2-level cement augmentation at the construct's proximal extent. SUMMARY OF BACKGROUND DATA: Prevention of PJF after thoracolumbar fusions is critical because they may result in neurological injury. Cement augmentation of constructs' proximal vertebrae is postulated to decrease PJF.
METHODS: Patients with ASD after PSF from pelvis to thoracolumbar junction with 6 months or more follow-up were retrospectively studied. Demographics, deformity radiographical parameters, and health-related quality of life outcomes (HRQoL) scores were compared with patients with no cement, 2-level cement augmentation at upper instrumented vertebra (UIV) and vertebra 1 level proximal to UIV (UIV+1), and cement at another location ("Other"). Revision surgery for PJF was primary outcome. Univariable and multivariable logistic regression analyses were used for statistical analysis.
RESULTS: 51 patients [female-29; male-22; average age: 65 yr (33-82)] met inclusion criteria (2-level-19; no-cement-23; "Other"-9). Average follow-up (mo) was longer for no-cement (25 ± 15) and "Other" (20 ± 16) than 2-level (15 ± 8) (P = 0.06). All perioperative radiographical parameters were similar, save first postoperative thoracic kyphosis and lumbopelvic mismatch. Compared with 2-level cement, non-2-level cement had significantly more revisions for PJF (0% vs. 19%; P = 0.02). After UIV adjustment, risks of PJF revision surgery were 13.1 times higher for "Other" (95% CI: 0.5-346.5, P = 0.12) and 9.2 times higher (95% CI: 0.4-239.1, P = 0.18) for no-cement. All HRQoL scores improved in 2-level cement; only back/leg pain significantly improved in non-2-level cement. Postoperative Oswestry Disability Index was significantly less in 2-level cement.
CONCLUSION: The use of 2-level cement augmentation (UIV and UIV+1) in PSF from pelvis to thoracolumbar junction for ASD is associated with a decreased rate of acute proximal junctional fractures and associated revision surgeries. As only associations can be demonstrated from this study's design, prospective investigations with larger, consecutive cohorts should be performed to explore causal relationships. LEVEL OF EVIDENCE: 3.