Diagnostic Performance and Safety of Endobronchial Ultrasound-guided Transbronchial Mediastinal Cryobiopsy in Diagnosing Tuberculous Mediastinal Lymphadenitis: a Randomised Controlled Trial

EBUS-TBMC is a minimally invasive bronchoscopic procedure performed under moderate sedation or general anesthesia to obtain larger and more intact tissue samples from mediastinal lymph nodes compared to conventional needle aspiration. A convex probe EBUS scope is used to identify the target lymph node, and Doppler mode is employed to map vascular structures for safe puncture path planning. A dedicated puncture dilation catheter is inserted under real-time EBUS guidance to puncture the airway wall and enter the target lymph node; the needle stylet is then removed, leaving the outer sheath in place to establish a "tunnel" from the airway lumen into the lymph node parenchyma. A flexible cryoprobe is advanced through the sheath into the lymph node, with ultrasound confirmation ensuring the probe tip is positioned within the node while maintaining a safety distance of at least 5 mm from the nodal edge and any visible blood vessels. The freezing system is activated using carbon dioxide as th

EBUS-TBNA is a standard minimally invasive bronchoscopic procedure performed under moderate sedation or general anesthesia to obtain cytological samples from mediastinal lymph nodes. A convex probe EBUS scope is used to identify the target lymph node, and Doppler mode is employed to map vascular structures for safe puncture path planning. A dedicated 22G EBUS aspiration needle is inserted under real-time ultrasound guidance to puncture the airway wall and enter the target lymph node. Standard "to-and-fro" movements are performed approximately 30 times per pass to aspirate cellular material. For this trial, a total of five independent needle passes are performed on the same target node. The specimen from the first pass is collected directly into sterile saline for mycobacterial culture. The remaining specimens are rinsed into 10% neutral buffered formalin for cell block preparation and histopathological evaluation. The rinsing fluid from the needle and specimen container is also collect