Comparison of Two Needle Agitation Strategies in Endobronchial Ultrasound-guided Transbronchial Needle Aspiration (EBUS-TBNA) for Diagnostic Yield

The goal of this clinical trial is to learn whether the number of needle agitations during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) affects diagnostic yield in patients with enlarged mediastinal lymph nodes. The study will also evaluate tissue sample quality and the safety of different needle agitation strategies. The main questions it aims to answer are: Does the number of needle agitations improve diagnostic yield? Does a higher number of needle agitations increase tissue core length and specimen adequacy? Are there differences in procedure-related complications between the two needle agitation strategies? Researchers will compare two needle agitation strategies during EBUS-TBNA to see if one approach provides better diagnostic performance, improved sample quality, and similar procedural safety. Participants will: * Undergo EBUS-TBNA as part of their clinical evaluation * Be randomly assigned to one of two needle agitation strategies * Have tissue samples measured for core length and assessed for diagnostic adequacy * Be monitored for procedure-related complications

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has become the standard minimally invasive modality for sampling mediastinal lymph nodes in patients with suspected thoracic malignancies and benign lymphadenopathies. Despite its widespread adoption and high overall diagnostic performance, variability in procedural techniques may contribute to heterogeneity in specimen quality and diagnostic yield. Among procedural factors, the number of needle agitations performed during each needle pass represents a modifiable technical variable that may influence tissue acquisition. Increased needle agitation may theoretically enhance tissue yield and core length by promoting mechanical dissection of nodal tissue; however, excessive agitation may also increase blood contamination, reduce sample interpretability, or elevate procedural trauma risk. Conversely, fewer agitations may limit tissue disruption but potentially result in inadequate sampling. Currently, there is no high-level evidence establishing an optimal agitation strategy, and operator-dependent variability remains common in clinical practice. This randomized, single-blind controlled trial is designed to compare two predefined needle agitation strategies during EBUS-TBNA. By standardizing all other procedural variables, the study aims to isolate the effect of agitation number on diagnostic performance. Objective procedural metrics, including measured tissue core length and specimen adequacy, will be systematically assessed to provide quantitative evaluation of sample quality. Procedural safety outcomes will also be monitored to evaluate whether differences in agitation strategy influence complication rates. The results of this trial are expected to provide evidence-based data to support technical standardization of EBUS-TBNA and to inform procedural guidelines aimed at optimizing diagnostic efficiency while maintaining safety.