Prospective registration study of diagnostic yield and sample size in forceps biopsy using a novel device under digital cholangioscopy guidance with macroscopic on-site evaluation.

Abstract

Although the SpyGlass Direct Visualization System can be clinically useful for diagnosing indeterminate biliary stricture, it employs SpyBite forceps, which typically obtain only a small amount of tissue and have a low sampling rate. An improved forceps biopsy device for SpyGlass DS has recently been released (SpyBite MAX). The aim of this prospective registration study was to assess the diagnostic yield and efficacy of histological biopsy tissue obtained with SpyBite MAX forceps compared with SpyBite forceps in patients with indeterminate biliary stricture. The primary outcome of the study was the diagnostic accuracy of biopsy specimens obtained by SpyBite MAX forceps. The secondary outcomes were tissue size, number of forceps biopsies, rate of obtaining adequate tissue, and adverse events in the SpyBite MAX forceps group compared with the SpyBite group. Forceps biopsies using SpyBite MAX (n=47) and SpyBite (n=50) were performed successfully in all patients. The number of biopsies performed before visible core tissue was obtained was significantly lower in the SpyBite (mean, 1.5 ± 0.7) than in the SpyBite forceps group (mean, 2.3 ± 1.1 mm; P < .001). Tissue sample size was larger in the SpyBite MAX group (mean, 1.8 ± 1.6 mm2 ) than in the SpyBite group (mean, 1.0 ± 0.9 mm2 ; P=.004) but there was no significant difference in diagnostic accuracy. Improvements in dedicated forceps for biopsy in SpyGlass DS may contribute to improving the rates of adequate tissue and tissue sample size obtained, and to reducing the number of forceps biopsies required.