Risk Factors for Abscess Development Following Percutaneous Microwave Ablation Therapy of Hepatic Tumors

Purpose: To investigate risk factors associated with post-microwave ablation (MWA) abscess development.

Materials and methods: A retrospective case-control analysis was conducted to identify hepatic MWA performed at a single tertiary medical center between January 2010 and January 2022. Case and control patients were defined as those who did or did not develop intrahepatic abscess within 3 months following MWA, respectively. Correlations between risk factors and post-MWA abscess development were assessed by Fisher's exact test.

Results: Between 2010 and 2022, 253 patients underwent 376 MWA sessions with post-ablation abscess complication rate of 1.1% (4/376). Complications associated with intrahepatic abscess included bacteremia, empyema, pleural abscess, subcutaneous abscess, cholangitis, bile leak, biliocutaneous and arterio-biliary fistulae, and pseudoaneurysm. One patient expired from septic shock 5 days post-ablation. All abscesses were treated by percutaneous drainage and antibiotics. One patient required concomitant placement of a biliary stent and embolization of a biliocutaneous tract. History of Sphincter of Oddi manipulation (p < 0.01), cholangiocarcinoma (p < 0.05), transarterial radioembolization (TARE) to the index lesion (p < 0.05), and abnormal serum alkaline phosphatase levels (p < 0.05) were significantly correlated with post-MWA abscess. The risk of developing post-MWA abscesses for patients with a history of cholangiocarcinoma or a history of Sphincter of Oddi manipulation were 20.0% and 27.2%, respectively.

Conclusion: Patients with prior Sphincter of Oddi manipulation, cholangiocarcinoma, or TARE are at greater risk of developing post-MWA abscess.