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Is Kyphoplasty Better at Restoring Vertebral Shape Than Vertebroplasty in Severe, Acute Vertebral Compression Fractures? 2013

Category General Spine Deborah J. Annesley-Williams
Priyan Landham
Holly Baker
Sam Gilbert
Phillip Pollintine
Michael Adams
Particia Dolan
Purpose Osteoporotic vertebral fractures can cause severe vertebral wedging and kyphotic deformity. This study tested the hypothesis that kyphoplasty restores vertebral height, shape and mechanical function to a greater extent than vertebroplasty following severe vertebral compression fractures. Materials & Methods Pairs of thoracolumbar “motion segments” from seventeen cadavers (70-97 yrs) were compressed to failure in moderate flexion and then cyclically loaded to create severe wedge deformity.  One of each pair underwent vertebroplasty and the other kyphoplasty.  Specimens were then creep loaded at 1.0kN for 1 hour.  At each stage of the experiment the following parameters were measured: vertebral height and wedge angle from radiographs, motion segment compressive stiffness, and stress distributions within the intervertebral discs.  The latter indicated intra-discal pressure (IDP) and neural arch load-bearing (FN).  image1.ppt Results Fracture and cyclic loading reduced anterior vertebral height by 34%, increased wedge angle from 5.0° to 11.4°, increased FN by 58% and reduced IDP and compressive stiffness by 96% and 44% respectively.  Kyphoplasty restored anterior height to a greater extent than vertebroplasty (p<0.001), by 96% versus 59% immediately after augmentation, and by 79% versus 47% after subsequent creep loading.  Wedge angle was also reduced to a greater extent following kyphoplasty than vertebroplasty (p<0.02) by 7.2° vs 4.2° after augmentation and 6.6° vs 4.0° after creep loading.  IDP, FN and compressive stiffness were restored to a similar extent by both procedures. image2.ppt Conclusion Kyphoplasty and vertebroplasty were equally effective in restoring mechanical function following severe wedge fractures, but kyphoplasty was better able to correct deformity by restoring vertebral height and reducing wedging References Spine Update Mechanical Testing of the Spine An Appraisal of Methodology, Results and Conclusions MA Adams Spine Vol 20 No 19 pp2151-2156 Mentored Award Mentored Award Question 1 No Response Question 2 No Response