Artificial Ascites for Pain Relief During Microwave Ablation of Subcapsular Liver Tumors

Purpose: To compare post-procedure pain of subcapsular hepatic metastasis treated with microwave ablation (MWA) with and without artificial ascites. Materials and Methods: During a 2-years period, 41 patients underwent MWA of 52 peripheral liver metastases including 20 patients (10 men and 10 women (mean ± SD age: 62 ± 9.3 years) who underwent MWA of 27 metastasis without artificial ascites (group 1), and 21 patients (12 men and 9 women (mean age: 63.5 ± 9.9 years) who underwent MWA of 25 metastasis with artificial ascites (group 2). Patient’s pain assessment cores [10-point visual analog scale (VAS)] at 6, 24 h, and 4 days after the MWA procedure were compared among groups, as well as 24 h cumulative morphine dose was also compared among groups. Complications were reported. Statistical significance was evaluated by Fisher’s exact test and Student’s t test. Results: Pain VAS were 8.6 ± 2.7, 3.9 ± 1.4, and 0.6 ± 1.2 at 6, 24 h, 4 days, respectively, for group-I and 0.8 ± 1.9, 0.3 ± 0.9, and 6.6 ± 3.5 for group II. Pain VAS were significantly different at 6, 24 h, and 4 days between the two groups (p < 0.0001). The average 24 h dose of morphine was 5.8 ± 2.2 mg in group-I and 0.2 ± 0.6 mg in group-II (p < 0.0001). Complications occurred in two patients from group-I (10 %), including one bilio-pleural fistula and one minor cutaneous burn. One patient (9.5 %) in group-II developed a lobar infarction. No bleeding and no procedure-related death were reported. Conclusion: Artificial ascites prevents immediate post-procedural pain, which re-appears intensively 4 days later.