Establishing a standardized biomechanical model for osteoporotic pincer (OF4) Fracture creation in human cadaveric spines: a novel experimental technique

BACKGROUND: Osteoporotic pincer-type fractures (OF4) represent a distinct and challenging fracture subtype, yet the absence of reproducible experimental models limits scientific opportunities for biomechanical research and the development of tailored treatments. This study describes and validates a standardized method to generate OF4 pincer fractures in human cadaveric spines. METHODS: Twelve osteoporotic bisegmental thoracolumbar specimens underwent controlled fracture induction using a servo-hydraulic testing machine. Radiological assessment confirmed fracture morphology consistent with OF4 pincer-type fractures. RESULTS: OF4 fractures were successfully induced in eight specimens (mean age 73.5 ± 7.5 years; mean BMD 68.4 ± 7.2 mg/cm³). Four specimens were excluded due to fracture patterns inconsistent with OF4 pincer-type morphology (instability, scoliosis, asymmetrical collapse, or comminution). Biomechanical testing revealed significant increases in range of motion post-fracture in flexion/extension (+ 9.6° ± 2.4°, p < 0.001), lateral bending (+ 16.2° ± 7.8°, p < 0.001), and axial rotation (+ 6.0° ± 4.3°, p = 0.01). Central vertebral body height loss reached 55% (p < 0.001), reflecting hallmark characteristics of clinical OF4 pincer fractures. CONCLUSION: This protocol offers a reproducible and biomechanically validated model of osteoporotic OF4 pincer fractures. It presents a model that can potentially be used for biomechanical evaluation of surgical interventions and the development of novel techniques.