The Impact of Local Anesthetic Volume and Concentration on Pain During Prostate Biopsy: A Prospective Randomized Trial

Purpose: To evaluate the effect of equivalent doses of local anesthetic administered at different concentrations and volumes on pain scores in patients undergoing prostate biopsy. Patients and Methods: This study was a single-center, randomized trial. A total of 120 patients were randomized into two groups with 60 patients in each group. In group 1, 2.5 mL of 2% lidocaine (low volume-high concentration) and in group 2, 5 mL of 1% lidocaine (high volume-low concentration) was injected just lateral to the junction between the prostate base and seminal vesicle on each side under ultrasonographic guidance. Patients were given an 11 point visual analog scale (VAS) to evaluate the level of pain encountered during transrectal ultrasonographic (TRUS) probe insertion, injection of the local anesthetic, and the biopsy procedure. Results: In both groups, TRUS probe insertion was the most painful stage of the procedure. With regard to local anesthetic injection, the VAS pain score was significantly lower in group 1 (1.56 vs. 2.41, P = 0.001). Concerning sampling of the prostate, group 1 had a significantly lower VAS pain score compared with group 2 (1.71 vs. 2.48, P = 0.008). Neither major complications nor side effects related to local anesthetic absorption occurred in both groups. Conclusion: Low volume-high concentration lidocaine administration provides superior analgesia compared with high volume-low concentration lidocaine during transrectal biopsy of the prostate.