A Preclinical Evaluation Comparing the Performance of a Novel 19-G Flexible Needle to a Commercially Available 22-G EBUS-TBNA Sampling Needle.

BACKGROUND: Needle samples may not provide sufficient diagnostic material for the assessment of mediastinal lymph nodes.

OBJECTIVE: The study compared the specimen size and diagnostic performance of a new 19-G endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) needle to that of a standard 22-G EBUS-TBNA needle in a swine model of granulomatous lymphadenopathy.

METHODS: Granulomatous inflammation was induced in mediastinal lymph nodes (LNs) of 10 domestic swine by injection of talc slurry. The affected LNs were sampled with the 19- and 22-G needles. Collected core tissue area and volume were determined using a specialized software and known needle internal diameter. The sample's quality was assessed using the biopsy core morphology grade (BCMG) as well as the biopsy diagnostic correlation grade (BDCG).

RESULTS: There was a significant increase in the average LN size from baseline (11.6 ± 3.2 to 15.2 ± 3.8 mm; p < 0.001) after talc injection. A total of 132 paired samples were collected from 38 LNs. The average mass and volume of the 19-G needle sample were larger than those of the 22-G needle sample: 33.78 ± 47.48 vs. 25.18 ± 32.08 mg (p < 0.002) and 11.40 ± 13.91 vs. 6.91 ± 6.42 mm3 (p < 0.0004), respectively. The pooled needle biopsy samples for the 19- and the 22-G needles had similar BCMG (1.38 ± 0.86 vs. 1.43 ± 0.87, p > 0.2) and BDCG (1.54 ± 0.93 vs. 1.57 ± 0.93, p > 0.2). The 19-G needle samples tended towards less blood contamination (p = 0.057), more often granuloma identification (46 vs. 32%, p = 0.2) and had more cartilage contamination (0.49 ± 1.46 vs. 4.81 ± 16.49% p < 0.003).

CONCLUSION: In experienced hands, the 19- and the 22-G EBUS-TBNA needles have a similar diagnostic yield in the swine model of granulomatous lymphadenopathy. The samples collected by the 19-G needle are larger and may have less blood contamination.