Accidental Bowel Transgression/Close Proximity During Percutaneous Microwave Ablation of Liver Tumors: A Retrospective Case Series.

Aim: Percutaneous liver ablation is a challenging procedure and operator-dependent. During the time when transarterial liver oncological therapies are favored over percutaneous liver ablation, we discuss the challenges of liver ablation with bowel interposition within the needle tract. Materials and

Methods

In this IRB-approved retrospective review, we analyzed 481 cases of percutaneous microwave ablation performed between 2012 and 2025 using the NeuWave microwave ablation system with 15 or 20 mm probes under non-contrast CT guidance, with needle trajectories planned based on ultrasound. Dissection techniques were not performed, as intraprocedural ultrasound and CT assessment suggested that the ablation zone would remain confined to hepatic parenchyma. Cases of bowel transgression or close proximity were identified on post-procedural CT imaging, with a follow-up duration of 3 months performed consistently across all cases.

Results

Three cases (0.6%) of bowel transgression or close proximity to bowel loops during needle placement were identified. There was no evidence of transmural bowel perforation or clinically significant bowel injury on clinical or radiologic follow-up. Post-procedural imaging demonstrated no free intraperitoneal air or fluid collections.

Conclusions

In cases where the ablation zone is confined to hepatic parenchyma, bowel proximity to or inadvertent traversal by the cooled antenna shaft may not result in clinically significant injury and can be managed conservatively in selected patients.