Wedge and needle liver biopsies show discordant histopathology in morbidly obese patients undergoing Roux-en-Y gastric bypass surgery

Background:Controversy exists over whether or not single-needle liver biopsies are sufficient to compare histological parameters in patients with non-alcoholic fatty liver disease.Aims:To identify sampling variability,we biopsied four liver specimens per patient,based on biopsy size(needle vs wedge)and location(left vs right lobe),immediately prior to bariatric Roux-en-Y gastric bypass surgery.Methods:Ten prospectively enrolled,morbidly obese patients underwent 40 laparoscopy-guided biopsies;two needle and two wedge from each of 16 left and 16 right liver lobes.The Kappa coefficient for concordance compared histological parameters from left and right lobe needle-and wedge biopsies.Wedge biopsies were considered our‘Gold Standard’.Results:Each patient had two wedge-and two needle liver biopsies.Kappa concordance between all needle and wedge biopsies from right and left lobes showed variability.Wedge-and needle liver biopsies from contralateral lobes had higher concordance with each other,compared to ipsilateral needle/wedge biopsy pairs.Contralateral wedge pairs had higher concordance than contralateral needle/needle pairs.There were no biopsy complications.Conclusions:Wedge biopsy pairs had the best Kappa concordance but contralateral needle/needle biopsy pairs had good Kappa concordance.There were no complications from the 40 needle-and wedge liver biopsies,confirming the safety of laporoscopic multi-biopsy in both liver lobes.