Microwave thermal ablation of spinal metastatic bone tumors

To assess feasibility, safety, and efficacy of microwave ablation of spinal metastatic bone tumors.

Retrospective study of 17 patients with 20 spinal metastatic tumors treated with microwave ablation under computed tomographic guidance between March 2011 and August 2013 was performed. Ablations were performed under local anesthesia and nitrous oxide ventilation. Lesions were lumbar (n = 10), sacral (n = 7), and thoracic (n = 3) in location. Primary neoplastic sites were lung (n = 9), prostate (n = 4), kidney (n = 6), and uterus (n = 1). Adjunct cementoplasty was performed in nine cases, and a temperature-monitoring device was used in four cases. Procedure effectiveness was evaluated by visual analog scale (VAS) during a 6-month follow-up. Patient medical records were reviewed, and demographic and clinical data, tumor characteristics, and information on pain were assessed.

Mean ablation time was 4.4 minutes ± 2.7 (range, 1-8 min), with an average of 3.8 cycles per ablation at 60 W (range, 30-70 W). The preprocedure mean VAS score was 7.4 ± 1.2 (range, 6-9). Pain relief was achieved in all but one patient. Follow-up VAS scores were as follows: day 0, 1.3 ± 1.8 (P < .001); day 7, 1.6 ± 1.7 (P < .001); month 1, 1.9 ± 1.6 (P < .001); month 3, 2.2 ± 1.5 (P < .001); and month 6, 2.3 ± 1.4 (P < .01). No complications were noted.

Microwave ablation appears to be feasible, safe, and an effective treatment of painful refractory spinal metastases and may be considered as a potential alternative percutaneous technique in the management of spinal metastases.