Vacuum-assisted laser ablation induces pulmonary cavity formation: insights from a rabbit model

Pulmonary nodules are common findings in low‑dose CT screening, and thermal ablation is a minimally invasive treatment option. However, incomplete ablation and tissue fragment dispersion remain challenges.

In this rabbit model study, laser ablation and microwave ablation were performed at three energy settings (600 J, 1,200 J, and 1,800 J) under CT guidance. An innovative three‑way vacuum adapter was integrated with the puncture needle to apply negative pressure suction during ablation. Gross pathology, lesion dimensions, cavity formation, and histological features of aspirated tissue were assessed.

Laser ablation consistently produced larger lesion site rhombus areas than microwave ablation at equivalent energy levels (e.g., 87.2 mm² vs. 53.1 mm² at 600 J; 179.2 mm² vs. 104.6 mm² at 1,800 J). Cavity formation occurred exclusively in laser groups, while none was observed in microwave groups. Aspirated tissue fragments collected during laser ablation contained alveolar epithelial cells and lymphocytes, confirming effective vacuum‑assisted extraction. Histology revealed concentric pathological zones with increasing energy.

The findings highlight the distinct advantages of vacuum‑assisted laser ablation over microwave ablation in pulmonary nodule treatment. Laser ablation with vacuum assistance not only produced larger lesion areas but also uniquely induced consistent cavity formation, which may serve as a marker of complete tumor eradication in various organ systems. Further experiment on larger animal models are warranted.

Laser ablation combined with vacuum assistance achieved more efficient ablation, larger lesions, and consistent cavity formation compared to microwave ablation. This approach may enhance tumor eradication and warrants further investigation for application to other organ sites.