Effect of prostate volume on the peripheral nerve block anesthesia in the prostate biopsy A strobe-compliant study

Objective: The objective of this study was to evaluate the anesthetic efficacy of periprostatic nerve block (PNB) in transrectal ultrasound (TRUS)-guided biopsy on different prostate volume. Methods: A total of 568 patients received prostate biopsy in our hospital from May 2013 to September 2015 and were retrospectively studied. All patients were divided into local anesthesia group (LAG) and nerve block group (NBG). Then each group was subdivided into 4 subgroups (20-40, 40-60, 60-100, and >100 mL groups) according to different prostate volume range. Visual analogue scale (VAS) and visual numeric scale (VNS) were used to assess the patient's pain and quantify their satisfaction. The scores and complications were compared between the groups. Results: The age and serum prostate-specific antigen (PSA) level before biopsy had no significant differences at intergroup or intragroup level. The VAS scores were significantly lower in the NBG than those in the LAG in terms of prostate volume (1 (1-2) versus 2 (1-3), 2 (1-3) versus 2 (2-4), 2 (2-3) versus 3 (2-5), 4 (3-5) versus 5 (4-7), all P<0.05). Conversely, the VNS scores were higher in the NBG (4 (3-4) versus 3.5 (3-4), 3 (3-4) versus 3 (3-3), 3 (2-4) versus 3 (2-3), 2 (2-2) versus 1 (1-2), all P<0.05). Patients with smaller prostate volume undergoing PNB or local anesthesia experienced significantly lower pain and higher satisfaction scores than those with large prostate. Whether in PNB or local anesthesia group, patients with large prostate volume had more chance to have hematuria, hemospermia, urinary retention than smaller one except infection (P< 0.05). Those complications had no significant differences between LAG and NBG (P>0.05). Conclusion: Compared with local anesthesia, ultrasound-guided PNB has superior analgesic effect and equal safety, but for patients with a large prostate volume, the analgesic effect is inefficient.