A Novel Bipedicular Dissociation Fracture Pattern of Vertebral Osteoporotic Fractures of the Elderly.

Introduction: CVFs are common, with several classification systems available. We have encountered osteoporotic vertebral fractures (OVFs) with PDF, a never-described fracture pattern.This study evaluates this unique fracture's characteristics.

Methods: Retrospective study of surgically treated OVFs during 2016 to 2020.

Results: Of 105 patients, 85 had classifiable OVFs and 20 had uni-PDF (n = 10, 9.5%) or bi-PDF (n = 10, 9.5%). Both cohorts mainly had single vertebral fractures and upper end plate involvement with cleft sign found in 30% of PDFs versus 15.3% of OVFs (P < 0.001), higher incidence of burst fractures (40% vs. 25.9%; P < 0.001). Posterior vertebral body collapse was higher for PDFs (13.2 ± 9.3% vs. 18.3 ± 8.5%; P = 0.02). Most OVFs underwent balloon kyphoplasty (BKP) (94%). Most bi-PDFs were regarded unstable; six patients underwent PSF (2 short PSF, 1 PSF + BKP, and 3 BKP with intravertebral pedicular lag screws at the fractured vertebra). Half of the bi-PDFs underwent BKP-developed nonunion.

Conclusion: Our study is novel in describing an unrecognized OVF pattern disregarded in current classification systems. We found notable differences in fracture characteristics, prefracture functional status, and surgical results between OVF and PDF cohorts. We suggest adding this fracture pattern as a unique OF-4 subtype or a specific entity between OF-4 and 5, with uni-PDF as type A and bi-PDF as type B.