Pulmonary cement embolism after augmentation of pedicle screws with bone cement

The authors present the very rare complication of widespread pulmonary artery cement embolism after pedicle screw augmentation with bone cement for multilevel spine fusion. A 69-year-old woman with severe osteoporosis underwent a posterior T12S1fusion because of lumbar scoliosis. After two months the superior pedicle screws loosened, and a revision spondylodesis T8L1 was performed with bone cement augmentation of the pedicle screws. Although cement leakage was seen paravertebrally, the patient was asymptomatic and reported distinct pain relief, so that no further investigations were initiated. Three months later, instability was identified in the adjacent superior segment. A CT-scan of the chest now revealed multiple pulmonary cement embolisms. Corpectomy T7 and extension spondylodesis T6T9 with an anterior single rod were performed. The pulmonary embolisms remained clinically silent and lung function was normal 18 months after surgery. The risk for cement embolism after pedicle screw augmentation has been established at 1/119 or 0.8%. After vertebroplasty and kyphoplasty it ranges from 3 to 23%. The existing literature offers no clear strategy for prevention or treatment of pulmonary cement embolism. The authors feel, as far as prevention is concerned, that creating a cavity by means of balloon distention before pedicle screw augmentation allows to inject the cement under lower pressure, so that the incidence of cement embolism might be reduced. Treatment options include, besides surgical removal in symptomatic embolism, heparin or warfarin treatment for 3 to 6 months.