A new technique of ultrasound guided percutaneous renal biopsy by perforated probe and perpendicular needle trajectory

The percutaneous biopsy of native kidneys according to the classical methodology is performed under real time ultrasound guidance with the needle introduction along a trajectory of about 30°, aimed to the lower pole of the kidney. Recently, a variant of the classical technique has been introduced by which a perforated ultrasound probe is used to guide the needle along a perpendicular trajectory to the terminal section of the lower kidney pole where the front and back margins of the cortical kidney tissue join each other without renal sinus interposition so to offer to the needle a 3-4 cm thick cortical tissue front which allows to obtain a cortical tissue sample suitable for histological examination even with a single needle pass, while at the same time limiting the possibility of damaging the smaller kidney calices of the lower group whose lesion causes hematuria. In this paper, we present a large survey (50 patients) to compare to data from the literature obtained by using similar needle gauge and with a similar follow-up period after biopsy. The result of this comparison confirms the efficacy of this variant of the classical technique because in front of a statistically lower number of needle passes, it allowed to obtain 100% of samples suitable for histological analysis, in absence of major complications and with a statistically lower post-biopsy hemoglobin drop in comparison to that observed in a group of 44 patients biopsied with a greater number of needle passes, in the only study of the literature which is directly comparable to our study in relation to needle gauge and duration of monitoring.