The 22-gauge core needle is not optimal for endoscopic ultrasound-guided liver biopsy

We read with interest the study on endoscopic ultrasound-guided liver biopsy (EUS-LB) with a 22-G core biopsy needle [1], and the accompanying editorial [2]. This is not the first prospective study of a 22-G fine-needle biopsy (FNB) needle for liver biopsy as the authors suggest; we published a prospective randomized study [3] comparing the 22-G FNB needle (fork tip) with a regular 19-G fine-needle aspiration (FNA) needle, as cited in both the article and the editorial. We found adequate cores in 68 % of EUS-LBs done with the 22-G FNB compared with 90 % with the 19-G FNA needle. There was increased fragmentation during standard tissue processing of 22-G FNB specimens, probably because of the smaller diameter of the cores (about half the diameter on average vs. the 19-G needle).

An experienced pathologist can deal with fragmented cores, but this may not be the case in general pathology practice. The 100 % “adequate diagnostic yield” in the Hasan et al. study can only occur with interpretation by experienced liver pathologists. Every effort should be made to deliver the best possible specimens to the pathologist. The 19-G needle, particularly the 19-G core needle [4] is the most reliable way to do this.

An additional benefit of the larger needle is that special needle maneuvers as described in the article (limited elevator use, straightening the needle, slow stylet insertion) are not necessary, decreasing the chances of user error. We agree with Larghi to limit the number of needle throws; we currently use 1 – 3 to-and-fro movements with fanning and full wet suction with heparin [5].

Many different techniques for EUS-LB work well. The 22-G needle may be less daunting for inexperienced endosonographers. However, the safety of 19-G needles is outstanding, and the larger size is more likely to obtain histologically adequate specimens in general use.

• References

• 1 Hasan MK, Kadkhodayan K, Idrisov E. et al. Endoscopic ultrasound-guided liver biopsy using a 22-G fine needle biopsy needle: a prospective study. Endoscopy 2019; 51: 818-824
• 2 Larghi A. Which needle and technique should we use for endoscopic ultrasound-guided liver biopsy? A work in progress. Endoscopy 2019; 51: 811-812
• 3 Mok SR, Diehl DL, Johal AS. et al. Endoscopic ultrasound-guided biopsy in chronic liver disease: a randomized comparison of 19-G FNA and 22-G FNB needles. Endosc Int Open 2019; 7: E62-71
• 4 Ching-Companioni RA, Diehl DL, Johal AS. et al. 19 G aspiration needle versus 19 G core biopsy needle for endoscopic ultrasound-guided liver biopsy: a prospective randomized trial. Endoscopy 2019; DOI: 10.1055/a-0956-6922.
• 5 Mok SRS, Diehl DL, Johal AS. et al. A prospective pilot comparison of wet and dry heparinized suction for EUS-guided liver biopsy (with videos). Gastrointest Endosc 2018; 88: 919-925