How is kyphoplasty performed?

Updated: Jul 29, 2020
  • Author: Jeffrey P Kochan, MD; Chief Editor: Felix S Chew, MD, MBA, MEd  more...
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Answer

Kyphoplasty is a refinement of the vertebroplasty procedure. In addition to the reduction of fracture-related pain, some or all of the height is restored to the compressed vertebral body. Normalizing the height of the fractured vertebra reduces the focally exaggerated curvature of the spine (ie, kyphosis). This effect, in turn, results in an esthetic improvement, improved posture, and a reduced risk of fracture of the adjacent vertebra as a result of abnormal load bearing. The restoration of a more normal appearing configuration of the vertebral body and improvement in the load-bearing physics is accomplished with the intravertebral inflation of 1 or 2 high-pressure balloon tamps (KyphX; Kyphon). As with vertebroplasty, access is via a transpedicular or peripedicular approach. The procedure distracts the fragments and elevates the collapsed vertebral endplate. The inflated balloons create cavities in the vertebral body, the margins of which are lined by the displaced, fragmented trabeculae.

In kyphoplasty, a KyphX inflatable bone tamp is percutaneously advanced into the collapsed vertebral body (A). It is then inflated, (B) elevating the depressed endplate, creating a central cavity, and compacting the remaining trabeculae to the periphery. Once the balloon tamp is deflated and withdrawn, the cavity (C) is filled under low pressure with a viscous preparation of methylmethacrylate (D). See image below.

In kyphoplasty, a KyphX inflatable bone tamp is pe In kyphoplasty, a KyphX inflatable bone tamp is percutaneously advanced into the collapsed vertebral body (A). It is then inflated, (B) elevating the depressed endplate, creating a central cavity, and compacting the remaining trabeculae to the periphery. Once the balloon tamp is deflated and withdrawn, the cavity (C) is filled under low pressure with a viscous preparation of methylmethacrylate (D).

The degree to which the height of the vertebral body and the angulation of depressed endplates are corrected appears to vary from case to case. The maximum volume of the balloon and the pressure required for inflation determine the inflation of the balloons, and therefore, the degree of height restoration. See image below.

Reduction in kyphotic angulation after kyphoplasty Reduction in kyphotic angulation after kyphoplasty.

Once height is improved, the balloon catheters are deflated and withdrawn. A preparation of methylmethacrylate thicker than that used in vertebroplasty is then injected under relatively low pressure into the cavities created by the inflated balloons. This procedure is used to maintain the elevation of the endplate and stabilize the fracture fragments, thereby reducing or eliminating pain and promoting healing (see images below). Because this acrylic is more viscous that that used for vertebroplasty and because it is injected under lower pressure that in vertebroplasty, the risk of intravascular extension of acrylic is thought to be lower.

This image was obtained in an 80-year-old man with This image was obtained in an 80-year-old man with a steroid-induced osteoporosis and a painful acute midthoracic vertebral compression fracture. Several additional chronic fractures are also present.
After inflation of balloon tamp, the depressed sup After inflation of balloon tamp, the depressed superior endplate is elevated, and some height is restored. The cavity is then filled with methylmethacrylate. Pain is reduced, and the patient's posture is improved.

The compact 4d trabeculae at the periphery of the acrylic acts as a bone graft, providing a dense matrix of bone upon which endosteal healing can occur. Kyphoplasty is most effective with acute compression fractures secondary to either trauma or osteoporosis, but it is not recommended for the treatment of fractures secondary to infection, most solid tumors, and vascular lesions. The presence of a burst fracture with loss of integrity of the posterior vertebral cortex and retropulsion of a fracture fragment into the spinal canal is considered exclusionary (see image below). Kyphoplasty is not indicated for the treatment of degenerative disk or joint disease.

A vertebral burst fracture is a fracture that cann A vertebral burst fracture is a fracture that cannot be treated safely by using vertebroplasty.

As with vertebroplasty, patients must exercise caution in subsequent activities because other osteoporotic vertebral bodies also may be prone to fracture. Medical management of the underlying disorder that weakens the vertebral bodies should be initiated. This procedure does not eliminate the need for aggressive treatment of osteoporosis, without which other fractures may ensue. Ideally, treatment should include risedronate (Actonel), alendronate (Fosamax), calcitonin (Miacalcin), calcium supplements, and multivitamins, including vitamins C and D. Hormonal replacement therapy should also be considered in female patients. Alterations in the medications and dosage of drugs that predispose patients to osteoporosis (eg, steroids) should also be evaluated. Progress should be monitored with serial DEXA scans.

In 1998, the FDA approved the use of this acrylic in kyphoplasty. To the author's knowledge, no investigators from long-term outcome studies have reported the breakdown of the acrylic over time. Preliminary clinical 2-year follow-up data from approximately 4000 kyphoplasties in more than 3000 patients is favorable.

Methylmethacrylate is an FDA-approved medical-grade tissue adhesive that has been used for more than 30 years in the fixation of artificial joint prostheses. Its use in vertebroplasty, however, is not approved by the FDA, which means that it has not been reviewed in the process whereby the government approves the bone cement and technique specifically used for this procedure. In vertebroplasty, the acrylic cement, which the FDA considers a medical device, is used in an off-label application.

Balloon kyphoplasty, a minimally invasive procedure for the treatment of painful vertebral fractures, was compared with nonsurgical care in an international, multicenter, randomized trial by Wardlaw et al. In the study, 300 patients with 1-3 acute vertebral fractures were randomized to kyphoplasty treatment (149 patients) or nonsurgical therapy (151 patients). In the kyphoplasty group, the mean short-form 36 physical component summary (PCS) score improved by 7.2 points (26.0 at baseline to 33.4 at 1 month) as compared to a 2.0 points improvement while the short-form 36 PCS score improved by 2.0 points (from 25.5 to 27.4) in the nonsurgical group (difference between groups 5.2 points, 2.9-7.4; p< 0.0001). The 2 groups did not differ in frequency of adverse events, and the authors concluded, based on the study findings, that balloon kyphoplasty is both safe and effective in patients with acute vertebral fractures and that the procedure may be considered as an early treatment option. [12]


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