Reply to Mok et al.
28 January 2020 (online)
Our study was the first prospective investigation using the three-pronged (Franseen geometry) 22-G fine-needle biopsy (FNB) needle. The difference in tissue adequacy (100 % vs. 68 %) between the two studies   is likely to be the result of different needle designs (two-pronged Fork-tip vs. three-pronged Franseen tip) and tissue acquisition-expression techniques used. While we agree with Larghi’s general premise, variation in needle tip design does not impact tissue quantitative yield , it may have a significant impact on qualitative measures such as core fragmentation. A recent study, comparing the performance of commercially available FNB needles for liver biopsy, found that the fork-tip needle yielded the lowest number of complete portal triads and the shortest cores .
The technique we described is simple and reproducible even by the less experienced endosonographer. To minimize core fragmentation, we simply avoided the use of the elevator and kept the needle straight while slowly inserting the stylet to express the sample. We did not require the use of heparin, suction or tedious rinsing of the sample after expressing.
22-G needles in general are more maneuverable, have a theoretically superior safety profile, and cause less post-procedure pain. Tissue fragmentation continues to be a concern, particularly when interpreted by non-GI trained pathologists. 19-G needles on the other hand, are less maneuverable, cause more post-procedure pain  and are daunting to use for the less experienced endosonographers.
The 22-G FNB needle is a viable and safe alternative to the 19-G fine-needle aspiration/FNB needle when used in the right clinical setting. We agree that further randomized multicenter experience is needed to determine the optimal technique, needle type, and patient population for endoscopic ultrasound-guided liver biopsy.
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