Pulmonary cement embolism after kyphoplasty

A 79-year-old woman undergoes kyphoplasty in order to multiple vertebral osteoporotic fractures. After that, she presents an increase in her usual dyspnea. Chest radiographs and computed tomography (CT) are performed.

PA and lateral chest radiographs show linear and curvilinear images of high-density material following the theoretical trajectory of pulmonary vessels.

In order to better characterize findings and rule out complications, chest CT is performed. It confirms the existence of radiodense material within the pulmonary arteries, secondary to kyphoplasty cement embolization.

Vertebral augmentation procedures, such as vertebroplasty and kyphoplasty, are minimally invasive surgeries for treatment of osteoporotic compression fractures but also other pathologies like osteolytic metastatic diseases, myeloma, or aggressive haemangioma [1][2]. Both involve the percutaneous injection of bone cement in the vertebral body. In the specific case of kyphoplasty, a balloon is previously inflated in the vertebral body to recover its height [3]. One of the complications of these procedures is the pulmonary cement embolism [4]. It is caused by the extravasation of cement to the external vertebral venous plexus and later to the azygos vein, superior cava, right heart, and finally pulmonary arteries [1][5]. This is a complication that appears in 3.5% to 25% of cases and its frequency is lesser in kyphoplasty than vertebroplasty in order to the characteristics of the technique. Cement used in kyphoplasty is denser than used in vertebroplasty, filling the cavities previously created by high-pressure balloons. Also, cement in kyphoplasty is injected at a lower pressure than in vertebroplasty to avoid leakage, thus having a theoretically lower risk of cement migration [2][6].

Most of these pulmonary embolisms are asymptomatic [2], but in a few cases may produce severe cardio-respiratory manifestations depending on the emboli location and size [3][6]. In symptomatic cases, patients may present dyspnea, tachypnea, chest pain or hemoptysis, and in rare clinical situations, hypotension, cardiorespiratory arrest, and death [6].

The diagnosis is performed by the visualization on chest radiography or chest CT -which is more sensitive and specific-, of radiodense material (more than 1000HU) inside the pulmonary arteries after a vertebral augmentation procedure [6]. Also, chest CT provides information regarding the status of the right heart and the presence of complications like pulmonary infarct. Right-sided heart failure signs include bowing of the interventricular septum or right atrial dilatation.

Depending on the severity of the symptoms, treatment options may change, but there are no clear therapeutic guidelines. In asymptomatic patients with peripheral embolisms, follow-up is recommended. In symptomatic or central embolisms is advised conservative treatment with anticoagulants. Surgical embolectomy may be reserved for massive central embolism with cardiopulmonary failure [1][2].

Given that our patient presents dyspnea and central embolism, treatment with anticoagulants is decided. She remains asymptomatic during the rest of the follow-up.

Take-Home Message

The presence of sudden dyspnea (or other respiratory symptoms) in patients recently undergoing kyphoplasty or vertebroplasty should make us think about pulmonary cement embolism and chest X-ray or CT is recommended for early diagnosis.