A new core-biopsy instrument with an end-cut technique provides prostate biopsies with increased tissue yield

Objective To evaluate the tissue yield of a new core-biopsy needle with an end-cut mechanism when used for transrectal prostate biopsies. Patients and methods The end-cut instrument has an adjustable stroke length (13. 23 or 33 mm) and an inner and an outer cannula, but no trocar. It was compared with the conventional side-notch needle (Biopty, Bard, Covington, GA. USA) with trocar and fixed stroke length (22 mm). In 60 men, octant biopsies were taken including the apex, mid-medial, mid-lateral and basal positions. At random. the left side or the prostate was biopsied with one of the instruments and the right side with the other. The length and weight of the biopsy specimens were measured. In 40 men, the stroke length of the end-cut instrument was set to 23 mm, and in 20 men it was set to 33 mm. Results The weight and the weight per length of the biopsies provided by the end-cut instrument with a stroke length of 23 mm were 18.4% and 13.7%, respectively, greater than in the biopsies from the side-notch instrument (P<0.001). In 21.9% of the attempts no tissue was obtained by the end-cut needle, compared with with the side-notch needle. With a 33 mm stroke length, the length and weight of the end-cut biopsies were 38.4% and 33.0%, respectively. greater than in biopsies from the side-notch instrument. Conclusion The end-cut instrument provided a greater tissue yield than the side-notch needle, but a significant number of biopsies were lost.