Prevention of vertebroplasty-related pulmonary bone cement embolism by IVC filter
Prevention of pulmonary bone cement embolism via IVC filter capture of vertebroplasty-related bone cement intravasation
A 77-year-old woman with a history of osteoporosis and deep vein thrombosis s/p IVC filter placement presents to the ED with a complaint of low back pain. She reports that the pain is recurrent and she recently underwent vertebroplasty approximately 6 weeks earlier at an outside institution for treatment of multiple thoracolumbar vertebral body compression fractures.
Surgical cement extravasation into the circulatory system is a frequently described complication of vertebroplasty. Although most patients with minor leaks are without symptoms, some disastrous consequences due to cement embolus have been reported, including renal failure, ischemic stroke, and cardiac perforation. The leakage may in part be attributed to the nature of the venous drainage at the site of injection. The vertebral body is highly vascularized with numerous intraosseous vertebral veins which form a freely communicating plexus. Osteoporosis and demineralization of vertebral bodies also plays a role in cement extravasation as compression fractures destroy internal trabecular scaffolding and thereby reduce bony hindrance of venous drainage. This allows a direct shunt of still-viscous cement into venous and occasionally, pulmonary circulation. Moreover, a small gauge needle is used to inject the compressed vertebral bodies. In order to overcome the resistance against the small-diameter needle, more liquidity and hence, less curability, is required which further increases the risk of methyl methacrylate monomer extrusion. The placement of IVC filters has become the standard of care to prevent thromboembolic material, usually from deep venous thrombosis in the lower extremities, from reaching the pulmonary circulation. However, cases with foreign materials becoming trapped in filters have not been reported frequently. The capture of bone cement by an IVC filter, while fortuitous in its prevention of pulmonary cement embolus, will undoubtedly change vascular flow dynamics within the IVC. The short term consequence of such an occurrence appears clinically inconsequential. However, the long term consequences of this event remain unknown. Additionally, with fewer than 5 cases reported in the literature, there is no standardized method of cemented filter retrieval.
Given the increasing number of patients undergoing both IVC filter placement and vertebroplasty, the frequency of IVC filter entrapment of extravasated bone cement could, theoretically, be on the rise.