Microwave Thermoablation of Colorectal Liver Metastases Close to Large Hepatic Vessels Under Pringle Maneuver Minimizes the "Heat Sink Effect".

Abstract

Liver resection and thermoablation are the mainstay of the surgical management of colorectal liver metastases (CRLM). The main limitation of thermoablation is the "heat-sink" effect for nodules next to large vessels. Herein, we report the preliminary results of microwave ablation (MWA) with associated Pringle maneuver to overcome this flaw. From November 2017, we performed intraoperative MWA with Pringle maneuver for nodules ≤3 cm with immediate proximity to large vessels (distance ≤ 5 mm, diameter ≥ 3 mm). We collected characteristics of nodules, surgical procedures and postoperative morbidity. Diameter of the ablation area, especially the ablative minimal margin, was calculated for each nodule. Recurrence was also evaluated. Nineteen patients underwent MWA with Pringle maneuver for 23 nodules. Nineteen (83%) ablated nodules were located in segments VI, VII and VIII, and one nodule was in segment I. Median size of nodules was 15 mm (10-21). No deaths occurred. Six patients (38%) experienced complications, among them only one was subsequent to the thermal ablation. Ablative minimal margin was ≥5 mm for 19 (83%) nodules. Margin was not sufficient for four nodules, among them only 2/23 cases (8.7%) of in situ recurrence occurred after 12 months of median follow-up. In this preliminary study, MWA with Pringle maneuver was associated with a low related morbidity rate and favorable oncological outcome, especially when the radiological minimal margin was sufficient.