Vertebroplasty vs kyphoplasty

First, we would like to clarify that kyphoplasty is a generic term for augmentation of the vertebral body in which sagittal alignment is specifically sought. In Europe, kyphoplasty devices using nonballoon technology are available.

Second, balloon kyphoplasty devices (manufactured by Kyphon Inc, Sunnyvale, Calif) are more expensive than vertebroplasty, as Dr. Ullman notes. Whether longterm costs differ between the 2 procedures is not known. The reader should note that neither balloon kyphoplasty nor vertebroplasty require general anesthesia or an overnight hospital admission. Whereas it is true that balloon kyphoplasty was originally performed as an inpatient procedure under general anesthesia, in the authors’ practice (Dr Truumees), most balloon kyphoplasty procedures are performed in an outpatient setting under conscious sedation.

Third, while balloon kyphoplasty may be associated with more radiation exposure and/or longer operative times, it also has more operative goals than does vertebroplasty, namely restoration of spinal alignment. Direct comparisons of operative times and radiation doses have not been published. Articles reporting radiation doses have varied in measurement techniques.^2-7

Fourth, height restoration has been reported in most articles concerning kyphoplasty, and many of the kyphoplasty articles also report restoration of vertebral body angles.^8-17 In vertebroplasty, some height restoration can be achieved by postural maneuvers (eg, intraoperative back extension), especially among dynamic fractures.¹⁸ On the other hand, kyphoplasty procedures begin with postural reduction, and two studies have shown that postural reduction contributes only a small portion of the final height restored during kyphoplasty.^19,20

Dr Ullman points out that volumetric CT or MRI may be better to analyze whether the central portion of the body is elevated, rather than looking at the endplates only as seen on conventional radiographs. We agree, and improvements in vertebral body volume with both vertebroplasty and kyphoplasty have been noted.^21,22

From a biomechanical perspective, height restoration and angular deformity correction may result in a reduced rate of subsequent fractures by reducing anterior stress. To date, 2 controlled but nonrandomized studies have shown a decreased rate of subsequent fracture after balloon kyphoplasty as compared to after nonsurgical management.^23,24

However, Dr Ullman is absolutely correct that a head-to-head comparison of vertebroplasty and kyphoplasty has not yet been published. We are aware of some efforts along these lines, including an industry-sponsored study. In the mean time, it seems reasonable that family physicians should refer patients for vertebral body augmentation with vertebroplasty or kyphoplasty according to local practices and levels of expertise.

Stephen Brunton, MD
Director of Faculty Development, Cabarrus Family
Medicine Residency, Concord, NC