Timing interval from peri-prostatic block to biopsy impacts procedural pain

Introduction: To compare visual analog scale (VAS) pain scores between patients with a 2-minute versus 10-minute delay of peri-prostatic lidocaine injection prior to transrectal ultrasound-guided prostate biopsies (TRUS-bx). Materials and methods: Eighty patients who underwent standard 12-core TRUS-bx by a single surgeon were prospectively randomized into four different treatment arms: bibasilar injection with a 2-minute delay, bibasilar injection plus a single apical injection with a 2-minute delay, bibasilar injection with a 10-minute delay, and bibasilar injection plus a single apical injection with a 10-minute delay. Patients were asked to report their level of pain on the VAS (0-10, with 10 indicating unbearable pain) at the following intervals: probe insertion (baseline), after each core, and post-procedure. The primary outcome measure was mean VAS score across all 12 cores minus baseline VAS score, which we refer to baseline-adjusted mean VAS score. Results: Baseline-adjusted mean VAS score was significantly higher for the 2-minute delay group compared to the 10-minute delay group (mean: -0.7 versus -1.6, p = 0.025). Subset analysis of biopsies 1-3, 4-6, 7-9 and 10-12 also demonstrated higher baseline-adjusted mean VAS scores in the 2-minute delay group (all p = 0.043). Conclusions: Lower TRUS-bx VAS scores can be achieved by extending the time from lidocaine injection to onset of prostate biopsy from 2 to 10 minutes.