Case Presentation: A 51-year-old female with no significant medical history presented to the hospital after a ground-level fall with severe thoracic back pain, paresthesia, paresis of both lower extremities and urinary incontinence. Exam revealed thoracic spine tenderness, bilateral diminished sensation up to two inches above the umbilicus and 1/5 bilateral lower extremity strength. Spinal MRI revealed multiple spinal lesions, a pathologic T7 compression fracture and severe cord compression due to epidural tumor extension. This prompted urgent thoracic spine open reduction and internal fixation, vertebroplasty with posterior fusion of T5-T10 and T7 corpectomy. Tissue pathology revealed hormone receptor positive, metastatic breast cancer.On postoperative day (POD) 2, the patient developed pleuritic chest pain and dyspnea. Patient was tachycardic (rate 102), hypoxemic (O2 89%) and hypotensive (99/49) in the context of blood loss anemia (Hb 7.7; preoperative Hb 10). On exam, the patient was in respiratory distress and lungs were clear to auscultation. The patient received two liters/min of oxygen via nasal cannula with saturation above 92% and one unit of packed red blood cells. Chest CT with IV contrast showed cement emboli extending from the azygos vein into the right atrium, and in bilateral pulmonary arterial branches of the upper lobes.On POD 5, enoxaparin 40 mg daily was started. After development of heparin induced thrombocytopenia, patient was transitioned to apixaban 2.5 mg twice daily. The patient was weaned off supplemental oxygen on POD 10 and discharged with improved mobility and pain control.

Discussion: Vertebroplasty is a procedure in which cement is injected into the compressed vertebral body to restore structural stability. Pulmonary cement embolisms are a serious complication of vertebroplasty, with a reported frequency of 3.5 – 23%. Though the exact mechanism is unclear, it is proposed that cement leaks into the paravertebral venous plexus then embolizes to the pulmonary arterial system. If the embolism occurs intraoperatively, patients may exhibit bradycardia, hypotension and hypercapnia. The most common postoperative symptom is dyspnea, with other signs and symptoms including pleuritic chest pain, tachycardia, hypoxia, and lightheadedness.There are no established guidelines for management; however, the general treatment strategy across various reports is based on embolus location and patient’s clinical status. If the patient is asymptomatic, the clinician may monitor, or anticoagulate to mitigate the risk of secondary thrombus formation. There is limited evidence supporting the latter when considering increased bleeding risk. To balance therapeutic benefit with bleeding risk, Hematology recommended initiating prophylactic dose anticoagulation in our case. Heparinization is the first line anticoagulant followed by coumadin for 3-6 months. Rivaroxaban and apixaban for a minimum of 3 months are acceptable alternatives. If the patient is symptomatic and the embolus is centrally located, surgical embolectomy may be considered.

Conclusions: Our case adds to the sparse collection of literature on the diagnosis and management of pulmonary cement embolism. The clinician must maintain high vigilance for cement embolism in patients undergoing vertebroplasty. Our recommendation is to closely monitor oxygenation and hemodynamic status in the immediate postoperative period, pursue CT imaging as first line if embolism is suspected and anticoagulate based on clinical status.

IMAGE 1: Image 1. Cement embolus demonstrated in the azygos vein with extension into the right atrium.

IMAGE 2: Figure 2. Bilateral pulmonary cement emboli demonstrated in the pulmonary arterial branches of the upper lung fields.