3 The technologies
3.1 Vertebroplasty involves injecting bone cement, typically polymethylmethacrylate, into the vertebral body (the solid part of the vertebra), using local anaesthetic and an analgesic. Vertebroplasty aims to relieve pain in people with painful fractures and to strengthen the bone to prevent future fractures.
3.2 Several bone cements are available for vertebroplasty. The acquisition cost of the high-viscosity Confidence Spinal Cement System (Johnson and Johnson) is based on the number of vertebrae being treated. The average cost of the kit is £1472. Low-viscosity cements are available and, based on list prices provided by 2 manufacturers (Cook and Stryker); the Assessment Group estimated a cost of £800 per low-viscosity cement vertebroplasty procedure.
3.3 Kyphoplasty involves inserting a balloon-like device (tamps) into the vertebral body, using local or general anaesthetic. The balloon is slowly inflated until it restores the normal height of the vertebral body or the balloon reaches its highest volume. When the balloon is deflated, the space is filled with bone cement, and a stent may or may not be placed. This document covers kyphoplasty without stenting. Kyphoplasty aims to reduce pain and curvature of the spine.
3.4 The Kyphon BKP kit (Medtronic) is available in the UK for kyphoplasty. Kyphon BKP is a CE-marked, single-use sterile pack with a list price of £2600.50 and includes 2 Kyphon Xpander inflatable bone tamps, with Kyphon ActivOs bone cement with hydroxyapatite supplied as a separate component. Alternative cements with different costs for use in kyphoplasty are available.
3.5 Kyphoplasty with stenting involves inserting a small balloon catheter surrounded by a metal stent into the vertebral body using radiographic guidance and either local or general anaesthesia. The balloon catheter is inflated with liquid under pressure to create a space into which the stent is expanded. The balloon catheter is deflated and withdrawn, but the stent remains in the vertebral cavity into which high-viscosity polymethylmethacrylate bone cement is then injected. The stent's function is to prevent the vertebra from losing height after the balloon is deflated.
3.6 The available vertebral body stenting system (Synthes) consists of a stent catheter, an inflation system, an access kit and a balloon catheter if needed. The manufacturer stated that there is limited clinical evidence available for vertebral body stenting because it has become available only recently. Therefore, balloon kyphoplasty with stenting was not assessed in this appraisal.
3.7 For both vertebroplasty and kyphoplasty, adverse reactions can be caused by: needle insertion (such as local or systemic infection, bleeding and damage to neural or other structures); leakage of bone cement; displacement of bone marrow and other material by the cement; systemic reactions to the cement (such as hypotension and death); and complications related to anaesthesia and patient positioning (such as additional fractures of a rib or the sternum). In addition, there is a small risk that the balloon can rupture in kyphoplasty, which can result in the retention of balloon fragments within the vertebral body.