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From the *Department of Anesthesiology, College of Medicine, Seoul National University, Seoul, Korea; and Division of Chemical Engineering, College of Engineering, SoonchunHyang University, Cheon-an, Choongchungnamdo.
Address correspondence and reprint requests to Seung Zhoo Yoon, MD, PhD., Department of Anesthesiology, College of Medicine, Seoul National University, #28 Yeongeon-dong, Jongno-gu, Seoul 110-744, Korea. Address e-mail to monday1031{at}yahoo.co.kr.
Abstract
Although percutaneous vertebroplasty is a simple and generally safe method for the management of vertebral compression fractures, cement leakage outside the vertebral body is a potential source of serious complications. We report a patient who presented with dyspnea and edema five years after percutaneous vertebroplasty and underwent open-heart surgery. This case demonstrates an intraatrial thrombus and pulmonary thromboembolism caused by venous leakage of polymethylmethacrylate as a late complication of the procedure.
Percutaneous vertebroplasty has been used in increasing number of patients with compression fractures of the spine in recent years. Although there are as yet no prospective randomized trials to establish the long-term efficacy and safety of this technique, it is an effective and minimally invasive method for providing immediate relief of pain and for stabilizing the vertebral bodies. Osteoporotic fractures, metastatic tumors, multiple myeloma, and vertebral hemangiomas are the main indications of the procedure (1,2). Although it is a relatively safe technique, leakage of polymethylmethacrylate (PMMA) into the spinal canal or perivertebral veins can lead to devastating complications, such as spinal cord compression or pulmonary embolism.
We report the case of a patient with a right atrial thrombus and pulmonary thromboembolism caused by migrated PMMA, who had undergone percutaneous vertebroplasty five years before clinical manifestations appeared.
CASE REPORT
A 55-year-old woman was admitted for evaluation of mild dyspnea and edema lasting 4 weeks. The patient was in good health until she experienced these symptoms. She had had a cesarean delivery about 25 years before, and percutaneous vertebroplasty due to a compression fracture of L2, 5 years before.
Her initial work-up included a chest radiograph and an abdominal ultrasonograph, which revealed a foreign body in the inferior vena cava (IVC) reaching the right atrium (Fig. 1). Her transesophageal echocardiograph showed a right atrial thrombus with a diameter of 2.5 cm and two fixed tubular structures. One of them was extended from the hepatic vein into the right atrium and faced toward the interatrial septum and the other, a shorter one, was connected to the thrombus. Computerized tomographic angiography disclosed a linear catheter-like foreign body from the right hepatic vein to the right atrium, where it appeared to be divided into two pieces (Fig. 2). A pulmonary artery embolism obstructing the orifice of the left lower lobar branch was also observed. Lung scanning demonstrated ventilation-perfusion mismatch with reduced blood flow to the left lower lobe. Her laboratory values were within the normal range except for an increased plasma D-dimer level.
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We first assumed the foreign body was a guidewire from the central venous catheter that had bent in the right atrium. On further questioning of the patient, however, she denied having had any instruments, including central venous catheters, placed internally. After we considered our patient's history and radiologic findings, we assumed that the foreign body would be a PMMA string.
Anticoagulation was initiated and an open-heart surgery for foreign body removal and atrial thrombectomy was performed under cardiopulmonary bypass. A right atriotomy revealed an uneven, light gray mass, which was 2 cm long and 4 cm wide, with a thin, solid, pinkish-gray material attached to it. Total circulatory arrest was necessary to remove the remaining foreign body in the IVC, which extended from the hepatic vein to the right atrium. It was the same as the one in the right atrium and had a wire-like appearance, measuring 1 mm in diameter and 13 cm in length (Fig. 3). Chemical analysis with an infrared spectrometer proved that the PMMA was a key component of the foreign body attached to a thrombus and the one in the IVC.
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The patient made an uneventful recovery and was discharged seven days after surgery.
DISCUSSION
Percutaneous vertebroplasty was first described by Galibert et al. in 1984 for the treatment of vertebral hemangioma (3). This procedure has gained increasing popularity as a therapy for painful and disabling vertebral compression fractures in the past few years. Although clinical trials have proven percutaneous vertebroplasty to be an efficient and safe procedure, its complication rate ranges from 1% to 10% (2).
Reported complications include transient worsening of pain, infections, bleeding (chiefly in the patients with coagulopathies or receiving anticoagulation medications), and injuries to the nerve roots or adjacent organs (4). The major hazards of this technique, however, are linked to cement extravasation. If PMMA leaks into the spinal canal or neural foramen, partial or complete paraplegia can occur (5). PMMA extravasation into the perivertebral venous system can also cause several different complications. The rate of cement leakage outside the vertebral body reported in the literature is up to 73% of cases, with venous leaks reported up to 24% (6). Most patients with minor venous leaks, and even with pulmonary emboli detected by chest radiographs, remained asymptomatic (7,8). However, some lethal consequences, including fatal pulmonary embolism (9–11), paradoxical cerebral embolism (12), penetration of the right ventricle (13), renal artery embolism (14), and acute respiratory distress syndrome (15), have been reported.
Our experience indicates that an intracardiac thrombus and pulmonary thromboembolism can occur as late sequelae of venous leakage of bone cement. We presumed that the PMMA had migrated into the right atrium via the IVC and triggered the formation of the intraatrial thrombus. A part of the thrombus became dislodged from the right atrium and embolized into the pulmonary arterial circulation. Therefore, it took five years for our patient's symptoms to develop. Concerning the cases of symptomatic pulmonary embolism cited above, clinical manifestations from mild dyspnea to hemodynamic instability, such as hypotension, arrhythmia and hypocapnia, appeared during or immediately after the procedure (9,10). Symptoms and signs of other venous leak-induced complications also appeared during or directly after vertebroplasty. Hemiparesis caused by cerebral embolism, for example, was identified during recovery from an anesthesia (12). In one case, renal artery embolism brought about an intense flank pain and impaired renal function immediately after the procedure (14). In another case, flulike symptoms of acute respiratory distress syndrome appeared the next morning and progressed rapidly toward respiratory failure (15). Right ventricular rupture and acute pericarditis were also reported to manifest as severe chest pain eight days later and required open-heart surgery (13). The patient we present here, however, experienced her symptoms five years after vertebroplasty. A right atrial thrombus that might have caused an obstruction to blood flow passing through the tricuspid valve or pulmonary emboli coming off the thrombus may have contributed to the development of dyspnea and edema.
Although percutaneous vertebroplasty has many benefits, including its simplicity and comparative safety, it is not free from complications. The current case demonstrates the formation of an intraatrial thrombus leading to pulmonary thromboembolism as a late complication of the procedure.
REFERENCES
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