INTRODUCTION: Percutaneous vertebroplasty involves an injection of acrylic cement, polymethyl metaacrylate (PMMA), into a diseased vertebra for partial vertebral body remodeling and lumbar pain relief. Osteoporosis, fractures, metastatic tumors, multiple myeloma and vertebral hemangiomas are the main indications of the procedure. We report the case of a patient who developed pulmonary hypertension following migration of PMMA into the pulmonary arteries eight weeks following percutaneous vertebroplasty.
CASE PRESENTATION: This 54 year old woman developed right upper quadrant abdominal pain associated with nausea and vomiting. She had neither chest pain nor shortness of breath. She has a history of asthma, vocal cord dysfunction, and aortic valve disease (requiring an aortic valve replacement). She is maintained on coumadin for the valve. She underwent a kyphoplasty for osteoporotic compression fracture of multiple vertebral bodies eight weeks prior. Her examination revealed normal vital signs, a clear chest exam, and a crisp valvular heart sound. A computed tomography scan of the abdomen revealed hyperdense material in the inferior vena cava, lumbar veins, and right interlobar pulmonary artery (Figure 1). PFTs showed an FEV1 of 1.9 L (77%) and FVC 2.33(74%), FEV1/FVC of 82, TLC of 3.63(84%), RV of 1.29(84%) and a DLCO of 17.1(74%). A transthoracic echocardiogram revealed normal right ventricle size and systolic function with a pulmonary artery pressure of 50 mm Hg. Pulmonary artery pressure five months prior as determined by echocardiography was 36 mm Hg. As she remained clinically stable she was discharged continuing anticoagulation with coumadin. Followup six months later revealed no increase in symptoms and no clinical changes.
DISCUSSIONS: Pulmonary hypertension is a rarely reported complication associated with cement embolization. Percutaneous vertebroplasty was first described by Galibert et al. in 1984 for the treatment of vertebral hemangioma and is now being used for the treatment of severe osteoporosis. Under CT or image guidance, polymethylmetaacrylate (PMMA) is injected into the vertebral body transcutaneously. Although clinical trials have proven percutaneous vertebroplasty to be efficient and safe procedure, associated complications occur in up to ten percent of cases. The major hazard of this technique is caused by cement extravasations. Cement embolization can occur as a result of insufficient polymerization of the PMMA at the time of injection allowing migration to the inferior vena cava, incorrect needle position with the respect to the basivertebral vein or overfilling of the vertebral body allowing cement migration into the venous system (1). Reported complications include transient worsening of pain, infections, bleeding, and injuries to the nerve roots or adjacent organs. If PMMA leaks into the spinal canal or neural foramen, partial or complete paraplegia can occur. Most patients with minor venous leaks, and even those with pulmonary emboli detected by chest radiographs remain asymptomatic. However, some fatal complications, including ARDS, fatal pulmonary embolism, paradoxical cerebral embolism, penetration of the right ventricle and renal artery embolism have been reported (2). There is little reported evidence of the clinical course following cement embolization.
CONCLUSION: Embolization of cement following a vertebroplasty can occur. While often asymptomatic in nature in some instances fatal complications have been noted. Pulmonary hypertension following such embolization has been reported only rarely. In cases of suspected embolization, despite the lack of clinical symptoms, echocardiographic evaluation of the right ventricle with determination of pulmonary artery pressure measurements should be performed. Subsequent followup of clinical symptoms and pulmonary artery pressure will be important to help determine the natural history of this disease.
DISCLOSURE: Ghazaleh Bigdeli, No Financial Disclosure Information; No Product/Research Disclosure Information