Percutaneous kyphoplasty using polymethylmethacrylate (PMMA) has recently become available to provide spine stabilization and pain relief for compression fractures due to osteoporosis or osteolytic spinal metastasis.1 The procedure is being increasingly utilized with good results but is associated with a rare complication of cement embolization to the pulmonary arteries. We report such a case to help familiarize pulmonologists with this entity.
A 62-year-old man with MM and multiple vertebral compression fractures underwent a percutaneous kyphoplasty using PMMA under general anesthesia. He has a history of mild CAD and a pulmonary embolism (PE). He had been taking coumadin, which was held for the procedure.A needle was placed transpedicularly into the vertebral bodies (L1-L3). A total of 4cc of PMMA was injected in each pedicle at all levels, under fluoroscopy. At the level of L2, extravasation of cement was visualized in the paravertebral venous system, extending approximately 3-4 cm distally. The patient remained stable.While being monitored in the recovery unit, his vitals were: temperature = 38.4 C, HR = 100-110 (sinus tachycardia), systolic BP = 140. Oxygen at 4 liters/min by nasal cannula was required to maintainO2 saturation > 90%. On exam, he had bibasilar crackles. The patient had no respiratory complaints. He received 5mg of IV Lopressor for cardioprotection, which resulted in hypotension with a SBP in the 70-80 range for several hours, despite fluid boluses.The patient was treated with IV antibiotics, anticoagulation and incentive spirometry. The fever, tachycardia, hypotension and hypoxemia all resolved within 24 hours. He was discharged home three days after surgery. His baseline back pain had improved.DISCUSSION: Kyphoplasty involves the percutaneous injection of bone cement under fluoroscopic guidance into a collapsed vertebra. Case reports suggest at least 67% of patients experience immediate pain relief. Slight leakage of injected cement in the paravertebral venous system can occur in up to 65% of cases, but in a few cases cement can reach the inferior vena cava and then, the pulmonary arteries.123 Clinical impact has ranged from asymptomatic to pulmonary infarct and hypoxemia. Risk factors for occurrence of cement emboli include incorrect needle positioning, inadequate polymerization of the PMMA before injection, lack of biplane fluoroscopy, degree of fracture pattern and anomalous vascular anatomy.12 In our case multiple vertebrae were involved requiring a greater total amount of cement and the vertebral bodies were extremely disrupted.Treatment includes supportive care and anticoagulation to prevent clotting around the foreign material. One case of pulmonary artery embolectomy of the material was reported in a patient with extensive embolization with good results.4The differential diagnosis of post-operative distress in this patient included atelactasis, pneumonia, pulmonary embolus and fluid overload. These were all considered but CXR and CT suggested cement PE and aspiration pneumonia.
With increasing use of kyphoplasty, pulmonologists should be aware of the possibility of cement emboli. These can be suggested by CXR and diagnosed by CT. Besides supportive care, treatment must be individualized to the given case. It is not known whether the presence of cement embolus will have an adverse impact on the patient’s lung function.
A.A. Elshinawy, None.