Contrast-enhanced ultrasound-guided microwave tissue coagulation therapy for hepatic trauma: an experimental study.

Background: Nonoperative therapies for hepatic trauma have become more popular. Because there is a potential application of microwave tissue coagulation (MTC) in the minimally invasive management of hepatic trauma, this study aimed to evaluate the efficacy of contrast-enhanced ultrasound (CEUS)- guided MTC therapy for hepatic trauma.

Methods: Forty hepatic lacerations were created intraoperatively in 10 heparinized porcine livers. MTC therapy was performed under CEUS guidance. Two hours after MTC, CEUS and histopathologic examination were performed to assess the effect of MTC therapy.

Results: All hepatic lacerations with active bleeding were successfully controlled with MTC therapy. The bleeding times in grade II and III lacerations (192.0 +/- 108.0 seconds, 443.4 +/- 63.5 seconds, respectively) were longer than that in grade I (48.3 +/- 33.3 seconds; p < 0.01), and blood losses (24.8 +/- 6.5 g, 47.8 +/- 10.5 g) were also higher than in grade I (6.6 +/- 4.3 g; p < 0.01). All grade I lacerations (16 of 16, 100%), 7 grade II (7 of 16, 43.8%), and 3 grade III (3 of 8, 37.5%) were not enhanced on CEUS except for the electrode track appearing as a hyperechoic strip. In 9 grade II lacerations and 8 grade III lacerations, most of treated region was unenhanced apart from a few small regular vascular enhancements at the periphery of treated region. Histopathologic examination showed that there was no hematoma in any microwave-treated region and the hepatocytes in treated region were obviously necrotic.

Conclusion: MTC therapy is a simple and effective method and may have great potential in minimally invasive treatment of hepatic trauma.