Percutaneous Vertebral Augmentation and Thermal Ablation in Patients with Spinal Metastases

Abstract

Vertebral augmentation and thermal ablation offer radiologists a robust minimally invasive option for treatment of patients with spinal metastases. Such interventions are commonly combined and have proved safe and effective in the management of selected patients with vertebral metastases with durable treatment effects. Special attention to procedure techniques including choice of vertebral augmentation technique, choice of ablation modality, and thermal protection is essential for improved patient outcomes. This article provides a review of the most recent advances in vertebral augmentation and thermal ablation for the treatment of spinal metastases.

Keywords: ablation; bone cancer; interventional radiology; radiofrequency ablation; spine; vertebral augmentation.

Fig. 1

A 72-year-old man with metastatic hepatocellular carcinoma and painful T10 metastatic lesion. Axial ( a ) and sagittal ( b ) T1-weighted fat-saturated contrast-enhanced MR images show enhancing bone marrow replacing metastatic lesion in the right side of T10 vertebral body involving the posterior vertebral body wall and extending to the right posterior elements ( a and b , arrows). Radiofrequency ablation was performed for pain palliation and local tumor control using simultaneous bipedicular approach to treat the entire clinical target volume aligned with consensus recommendations of the International Spine Radiosurgery Consortium, for improved local tumor control rates and more durable pain palliation. Anterior-posterior ( c ) and lateral ( d ) fluoroscopic images during radiofrequency ablation show bipedicular placement of two electrodes with medial articulation of the distal segments to create confluent coalescent and overlapping ablation zones ( c , arrows). Note the 5-mm distance between electrode tips (width of spinous process as reference) ( c ). The first ablation is performed along anterior vertebral body (not shown). Subsequently, the electrodes are retracted to treat posterior vertebral body and pedicles ( d , arrow). Lateral fluoroscopic image ( e ) shows vertebral augmentation which was performed immediately following RFA for pathologic fracture prevention. Sagittal T1-weigthed fat-saturated contrast-enhanced MR image ( f ) obtained 3 months following treatment shows local tumor control with nonenhancing tumor cavity and thin enhancing granulation tissue along ablation zone margins ( f , arrows). Note hypointense cement within vertebral body ( f ).

Fig. 2

A 59-year-old woman with metastatic non-small cell lung cancer and painful L4 metastatic lesion. Axial ( a ) CT image shows osteoblastic metastatic lesion within right anterior L4 vertebral body (arrow). Cryoablation was performed for pain palliation and local tumor control. Axial CT images ( b–d ) during cryoablation show placement of a single cryoprobe within L4 vertebral body osteoblastic lesion ( b , open arrow). Active thermal protection of spinal cord is performed with epidural injection of carbon dioxide ( b and c , arrow). Passive thermal protection is performed by placement of a thermocouple within right L4–L5 neuroforamen for temperature monitoring ( c , open arrow). Note hypoattenuating ice call within the prevertebral soft tissues ( d , arrow). Ice ball is not discernable within the osteoblastic lesion.