Experimental Model of Proximal Junctional Fracture after Multilevel Posterior Spinal Instrumentation.
There is a high risk of proximal junctional fractures (PJF) with multilevel spinal instrumentation, especially in the osteoporotic spine. This problem is associated with significant morbidity and possibly the need for reoperation. Various techniques have been proposed in an attempt to decrease the risk of PJF but there is no experimental model described for in vitro production of PJF after multilevel instrumentation. The objective of this study is to develop an experimental model of PJF after multilevel posterior instrumentation. Initially, four porcine specimens including 4 vertebrae and instrumented at the 3 caudal vertebrae using a pedicle screw construct were subjected to different loading conditions. Loading conditions on porcine specimens involving cyclic loading along the axis of the center vertebral body line, with constrained flexion between 0° and 15° proximally, and fully constraining the specimen distally resulted in a fracture pattern most representative of a PJF seen clinically in humans, so to undergo human cadaveric testing with similar loading conditions was decided. Clinically relevant PJF were produced in all 3 human specimens. The experimental model described in this study will allow the evaluation of different parameters influencing the incidence and prevention of PJF after multilevel posterior spinal instrumentation.
Hôpital du Sacré-Coeur de Montreal, 5400 Boulevard Gouin Ouest, Montreal, QC, Canada H4J 1C5; Department of Surgery, Université de Montreal, CP 6128, Succursale Centre-Ville, Montreal, QC, Canada H3C 3J7; Department of Surgery, CHU Sainte-Justine, 3175 Cote-Sainte-Catherine, Montreal, QC, Canada H3T 1C5.
Jean-Marc
0000-0003-4524-3893
JM
Mac-Thiong
Hôpital du Sacré-Coeur de Montreal, 5400 Boulevard Gouin Ouest, Montreal, QC, Canada H4J 1C5.
Annie
A
Levasseur
Hôpital du Sacré-Coeur de Montreal, 5400 Boulevard Gouin Ouest, Montreal, QC, Canada H4J 1C5; Department of Surgery, Université de Montreal, CP 6128, Succursale Centre-Ville, Montreal, QC, Canada H3C 3J7; Department of Surgery, CHU Sainte-Justine, 3175 Cote-Sainte-Catherine, Montreal, QC, Canada H3T 1C5.
Stefan
S
Parent
Hôpital du Sacré-Coeur de Montreal, 5400 Boulevard Gouin Ouest, Montreal, QC, Canada H4J 1C5; Department of Mechanical Engineering, Ecole de Technologie Supérieure, 1100 Notre-Dame, Montreal, QC, Canada H3C 1K3.
Yvan
Y
Petit
D000368:Aged; D000818:Animals; D002102:Cadaver; D019245:Compressive Strength; D004195:Disease Models, Animal; D006801:Humans; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D013131:Spine / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D034421:Sus scrofa; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing