Case Presentation:

A 53–year–old female presented to the orthopedic clinic with complaints of left hip pain, back pain, and motor and sensory deficits. Imaging demonstrated multiple lytic bone metastasis and thoracic spinal cord compression. She was emergently admitted for decompression and fixation of the spine. Cement was used for vertebroplasty and stabilization of spinal fusion with the aide of intraoperative computerized tomography (CT). After an apparently uncomplicated operation, a radiologist reviewed the intra–operative CT images and found multiple high–density opacities in the thoracic vasculature. A non–contrasted CT of the chest confirmed opacities extending from the para–spinal region into the azygos vein and superior vena cava with emboli in the bilateral pulmonary arteries consistent with extensive cement emboli (Fig. 1). The patient remained unchanged both symptomatically and clinically and was safely discharged home. A repeat chest radiograph 4 months later demonstrated persistent high–density opacities in the lung parenchyma as expected.

Discussion:

Acrylic bone cement (polymethyl methacrylate {PMMA}) is used in a variety of procedures for diseases such as osteoporotic collapse, osteolytic metastasis, and multiple myeloma. Although the incidence of complications when using PMMA is low at 1–10%, the most serious complication is pulmonary embolism caused by cement. Vascular invasion and other extra–vertebral extravasations can occur when using PMMA, especially when working with highly vascular tumors. The true incidence of pulmonary cement embolism is unknown, with mostly case reports cited in the literature. Reported incidence ranges from 4.6 to 6.8%, with the vast majority being asymptomatic. Diagnosis is typically made via radiographs. Chest radiographs can typically detect the high–density cement particles compared with lung parenchyma; however, CT is a more sensitive study. Theoretical concerns exist regarding the risk of intravascular thrombus formation adjacent to cement deposits, as the foreign material may act as a nidus for thrombosis. Although there is no study to suggest systemic anticoagulation is beneficial in these patients, some authors recommend anticoagulation therapy for symptomatic patients.

Conclusions:

Hospitalists commonly comanage perioperative orthopedic patients, making it imperative to be aware of the diagnosis of cement embolism. Although the true incidence, outcomes, and treatment of this complication are not yet defined, keeping a high level of suspicion in patients undergoing procedures utilizing PMMA may help to cement the diagnosis.

Figure 1Noncontrasted CT of the chest demonstrating high–density opacities in the pulmonary arterial vasculature.