Ex Vivo Comparative Study Of The Kyphoplasty And Vertebroplasty

Objectives: To compare the kyphoplasty(KP) with vertebroplast(VP) in improvement of the biomechanical properties, restoration of vertebral body height and extravasation of cement.Methods: Twenty osteoporotic vertebrae were alternatingly assigned to either the KP or VP group. All vertebrae were compressed by 25% of their initial height using materials testing machine to create vertebral compression fractures and determine their initial strength and stiffness. They were recompressed to determine their augmented strength and stiffness after injecting the cement. Precompression, postcompression and posttreatment height of vertebrae were measured. All vertebrae were scaned by CT to observe morphology of fracture, cement distribution and extravasation before compression and after compression, tamp inflation andtreatment.Results: Both treatments resulted in significantly stronger vertebral bodies relative to their initial state (P<0.01) and restored vertebral body stiffness to their initial values. The kyhpoplasty treatment resulted in significant restoration (88%) of vertebral body height lost after compression, whereas vertebroplasty treatment resulted in a significantly lower restorationof lost height (28%)(P<0.01). The cement distribution in the KP group is regular. No extravasation of cement was found out of vertebral bodies in the KP group. But the cement distribution in the VP group is irregular. The cement extravasation was found in four samples in the VP group (extravasation into spinal cannula in 2,to anteriorlateral of vertebral body and into blood vessel in 1 and to anteriorlateral of vertebral body in 1).Conclusion: Both kyphoplasty and vertebroplasty can increase the strength and restore the stiffness of fractured osteoporotic vertebral bodies. But kyphoplasty is superior to vertebroplasty in restoring vertebral body height and decreasing cement extravasation.