Size of the transrectal ultrasound probe makes no difference in pain perception during TRUS-Bx under adequate local anesthesia

In the great majority of the cases, transrectal ultrasound guided prostate biopsy (TRUS-Bx) is the definitive step in the diagnosis of prostate cancer (CaP). Although this procedure is well tolerated by most patients, it can result in considerable discomfort that can effectively be overcome with local injection anesthesia. In this study, we evaluated the effect of the size (i.e., circumference) of the transrectal probe on pain during TRUS-Bx.One hundred and seventy eligible patients who had elevated total prostate specific antigen (tPSA) and/or abnormal digital rectal examination (DRE) were included in this study. Patients (pts.) were divided into three TRUS-Bx groups; Group I: 60 pts. underwent TRUS-Bx with newer B-K Type 8808 probe (circumference 58 mm) under injectable periprostatic anesthesia, Group II: 60 pts. underwent TRUS-Bx with B-K Type 8551 probe (circumference 74 mm) under injectable periprostatic anesthesia, and Group III: 50 pts. underwent TRUS-Bx with B-K Type 8551 probe (circumference 74 mm) without local anesthesia. Periprostatic injection anesthesia was performed with 10 cc, 1% lidocaine (5 cc on each side) 10 min before TRUS-Bx. Pain was assessed using a 10-point modified visual analog scale (VAS) 15 min after the biopsy procedure.Three groups were homogeneous with respect to age and tPSA, and no statistically significant difference was observed in terms of mean biopsy duration between the 3 groups. Most of the patients experienced no pain to slight pain in Groups I and II, but 66% of the patients had more than moderate pain (VAS ≥ 5) in Group III with mean VAS score statistically higher than the other two groups (Group I vs. III, P = 0.0001; Group II vs. III, P = 0.0001). Mean VAS score was not statistically different between Group I and II (P = 0.126). No statistically significant difference in VAS pain perception was observed between different age categories within the Group I, II, and III.In the absence of injectable local anesthesia, larger probe (74 mm) results in much higher VAS pain perception than same size and smaller (58 mm) probe used under injectable local anesthesia. However, under injectable local anesthesia, the size (circumference) of the transrectal probe (58 mm vs. 74 mm) does not result in any different pain perception during TRUS-Bx.