Bronchial branch tracing navigation in ultrathin bronchoscopy-guided radial endobronchial ultrasound for peripheral pulmonary nodule.

ABSTRACT

BACKGROUND: Most malignant peripheral pulmonary lesions (PPLs) are situated in the peripheral region of the lung. Although the ultrathin bronchoscope (UTB) can access these areas, a robust navigation system is essential for precise localisation of these small peripheral PPLs. Since many UTB procedures rely on automated virtual bronchoscopic navigation (VBN), this study aims to determine the accuracy and diagnostic yield of the manual bronchial branch tracing (BBT) navigation in UTB-guided radial endobronchial ultrasound (rEBUS) procedures. METHODS: Single-centre retrospective study of UTB-rEBUS patients with PPLs smaller than 3 cm over a two year period. RESULTS: Our cohort consisted of 47 patients with a mean age of 61.6 (SD 9.53) years and a mean target size of 1.91 (SD 0.53) cm. Among these lesions, 46.8% were located in the 6th airway generation, and 78.7% exhibited a direct bronchus sign. Navigation success using BBT was 91.5% based on positive rEBUS identification. The index diagnostic yield was 82.9%, increasing to 91.5% at 12 months of follow-up. Malignant lesions accounted for 65.1% of cases, while 34.9% were non-malignant. The presence of a direct bronchus sign was the sole factor associated with higher navigation success and diagnostic yield. Cryobiopsy outperformed forceps biopsy in non-concentric rEBUS lesions (90.9% vs. 50.0%, p < 0.05), but not in concentric orientated lesions. One pneumothorax occurred in our cohort. CONCLUSIONS: BBT as an exclusive navigation method for small PPLs in UTB-rEBUS procedures has proved to be safe and feasible. Combination of UTB with cryobiopsy remains efficient for eccentric and adjacently oriented rEBUS lesions.