2012 – Acute Proximal Junctional Failure Following Posterior Spinal Fusion for Deformity: Risk Factors and Radiographic Analysis Comparing Thoracolumbar To Upper Thoracic Failures
May 6, 2013 by VirginieL
AUTHORS: Hart RA1 Hostin R2, Bess S9, Line B9, Ames CP3, Kebaish K4, Burton DC5, Lafage V6, O’Brien MF1, Schwab FJ6, Shaffrey CI7, Smith JS7, Wood KB8
INSTITUTIONS:
- 1. Orthopaedic Surgery, Oregon Health Sciences University, Portland, OR, United States;
- 2. Orthopaedic Surgery, Baylor Scoliosis Center, Plano, TX, United States;
- 3. Neurological Surgery, University of California – San Francisco Medical Center, San Francisco, CA, United States;
- 4. Orthopaedic Surgery, Johns Hopkins University, Baltimore, MD, United States;
- 5. Orthopaedic Surgery, University of Kansas Medical Center, Kansas City, KS, United States;
- 6. Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY, United States;
- 7. Neurological and Orthopaedic Surgery, University of Virginia, Charlottesville, VA, United States;
- 8.Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA, United States;
- 9.Orthopaedic Surgery, Rocky Mountain Hospital for Children, Denver, CO, United States
Introduction: Acute proximal junctional failure (APJF) is a challenging complication following spinal deformity surgery. Recent data indicates APJF is not a homogeneous entity; multiple etiologies exist for APJF. Little data exists comparing APJF in the thoracolumbar spine (TL-APJF) to APJF in the upper thoracic spine (UT-APJF). Purpose: identify demographic and radiographic characteristics of patients suffering TL-APJF vs. UT-APJF.
Methods: Multi-center, retrospective analysis of spinal deformity patients suffering APJF within 6 months of posterior instrumented fusion >4 levels. APJF defined as 15 degree postop increase in kyphosis between upper instrumented vertebra (UIV) and UIV+2, fracture of UIV or UIV+1, or need for proximal extension of fusion. TL-APJF= failures between T7-L2; UT-APJK = failures betweenT1-6. APJF etiology defined as fracture (FX), soft tissue failure (ST), or UIV fixation failure (UFF). Demographic, operative and radiographic parameters were evaluated.
Results: 63 patients, mean age 65 years (range 14-81), mean fusion levels 9.1 (range 4-17), met inclusion criteria. TL-APJF were older, had fewer fusion levels, and greater change in lumbar lordosis (LL) vs. UT-APJF (p<0.05; Table). Preop to postop changes in UIV/UIV+2 angle, sagittal vertical axis (SVA), pelvic incidence (PI), and pelvic tilt (PT) were similar TL-APJF vs. UT-APJF (table). FX was most common failure mode in TL-APJF, ST was most common in UT-APJF (p<0.05; table). FX were older than ST (69.2 vs. 58.4, respectively; p<0.05). Change in UIV/UIV+2, SVA, PI, PT and LL were similar between FX and ST. Time of APJF onset and body mass index (BMI) was similar TL-APJF vs. UT-APJF and FX vs. ST.
Conclusion: APJF following spinal deformity surgery is a heterogeneous complication. Discrete considerations include level of UIV and mode of failure. Older patients and constructs with UIV in the TL spine most commonly fail via vertebral fracture while younger patients and constructs with UIV in the UT spine fail through soft tissue. Further research is needed to delineate effective preventative measures.