The clinical efficacy of ultrasound-guided percutaneous microwave ablation for rib metastases with severe intractable pain: a preliminary clinical study

Purpose: To retrospectively evaluate the clinical efficacy of ultrasound-guided percutaneous microwave ablation (US-PMWA) for patients with rib metastases that caused severe intractable pain. Materials and methods: From Jan 2016 to Apr 2018, 9 rib metastases from 7 solid tumor patients were treated with US-PMWA. The visual analogue scale (VAS), daily opiate intake doses, local tumor control and complications were recorded and analyzed. Results: The follow-up period ranged from 6 to 33 months (median: 16 months). The procedures were successfully performed in all of the patients by one ablation. The ablation power ranged from 30 to 60 W, and the ablation time was 610.0 +/- 317.5 s. The mean preablation VAS pain score was 8.1 +/- 0.7, whereas the mean VAS pain score at 72 h post-ablation was 3.3 +/- 0.5 (P<0.001). All of the patients needed to apply oral and/or intravenous injection opiates to relieve severe intractable pain before ablation, with daily opiate intake doses of 61.4 +/- 30.8 mg. After ablation, five patients did not need to apply any opiate treatments 72 h after ablation, and only two patients needed oral opiates (daily opiate intake doses: 30 mg and 20 mg). Recurrence was detected in three lesions at 6, 11 and 9 months after ablation, with the maximum diameter observed being more than 4 cm. All of the patients were alive during the follow-up period. No minor or major complications occurred. Conclusion: US-PMWA appears to be feasible, convenient, safe and effective in the palliative management of refractory pain caused by rib metastases. This treatment can improve the quality of life of patients and may also achieve promising local control of tumors.