A comparison of wedge and needle hepatic biopsy in open bariatric surgery

Morbidly obese patients, despite normal laboratory tests and no clinical evidence of liver disease, present a high prevalence of hepatic histological changes. Liver biopsy is able to provide the diagnosis, staging and assessment of follow-up of hepatic disease, thus helping to define clinical management. There is no agreement on which biopsy technique provides better material for analysis. Considering that subcapsular fibrosis is a common finding, sampling from deeper sites is necessary to achieve an adequate histological assessment.

A study was done in 264 consecutive morbidly obese patients who underwent open Roux-en-Y gastric bypass between July 2001 and Sept 2004, in whom an intraoperative liver biopsy was taken. The first 107 were wedge biopsies, and the last 157 were needle biopsies. The histological degree of steatosis, presence of fibrosis and adequacy of material from the 2 biopsy techniques were compared.

Degree of steatosis in both sampling techniques showed no statistical difference (P=0.132). The presence of fibrosis in wedge biopsies (46.1% fibrosis, n 41) was significantly higher than in needle biopsies (13.7% fibrosis, n 20), P<0.001. As expected, sample size of needle biopsies was smaller than that obtained by the wedge technique (P<0.001), but there was no difference in the quality of material obtained (P=0.95).

Needle biopsies were as effective as wedge biopsies in assessing the degree of steatosis in morbidly obese patients. More important, the presence of subcapsular fibrosis in needle biopsies was less than in wedge biopsies, suggesting an adequate tissue sample by the less invasive technique.