Development of a permanently controllable rotating biopsy device, part II: Competitive in-vitro testing of a cannula-like prototype compared to established end-cut and side-notch biopsy devices.

PURPOSE: To evaluate the quantitative and qualitative efficiency of a permanently controllable biopsy-cannula prototype with lancet-like helically bent cutting edge for safer biopsy compared to established end-cut and side-notch biopsy devices. MATERIALS AND METHODS: Each of the n = 100 specimens per organ and system were obtained by the prototype, an end-cut device and a side-notch device (18 gauge each) using a bovine liver, kidney and myocardium as the biopsy tissue. Quantitatively, the number of fragments, length in mm and weight in mg of the specimen were analyzed. Qualitatively, a histopathological analysis was performed with respect to tissue fragmentation, crush artifact and adequacy of tissue (score per category min. 1 and max 3). To identify significant differences (p < 0.025), chi-square and Kruskal-Wallis tests were calculated in the statistical analysis. RESULTS: For each of the n = 300 specimens, the one-piece fragment/mean length/mean weight were n = 232 / 10.34 mm/ 4.86 mg for the prototype, n = 210 / 12.16 mm/ 5.35 mg for the end-cut system and n = 248 / 11.63 mm/ 4.08 mg for the side-notch system. The differences reached a level of significance with p < 0.001. The mean histopathological score for the prototype/end-cut system/side-notch system was 5.60 / 5.60 / 5.25 for the liver, 5.65 / 4.65 / 4.60 for the kidney and 5.05 / 5.35 / 4.85 for the myocardium. The differences did not reach a level of significance for the liver/kidney/myocardium with p = 0.665 /p = 0.186 /p = 0.436. CONCLUSION: Compared to established core biopsy systems, the biopsy-cannula prototype offers diagnostically equivalent biopsy specimen quality in an in-vitro setting in bovine liver, kidney and myocardium.