Subcutaneous local anaesthetic after transperineal prostate biopsy under general anaesthesia : a randomised trial

OBJECTIVE: To determine whether subcutaneous local anaesthesia (LA) infiltration at perineal puncture sites reduces immediate postoperative pain after transperineal (TP) prostate biopsy performed under general anaesthesia (GA). METHODS: In this two-centre, patient-blinded, randomised, placebo-controlled trial, men undergoing TP prostate biopsy under GA (GATP biopsy) were allocated 1:1 to receive either 20 mL 0.5% bupivacaine or 20 mL normal saline, infiltrated subcutaneously into the perineal skin at the conclusion of biopsy. The primary endpoint was the proportion of patients reporting moderate-to-severe pain (visual analogue scale [VAS] score > 3) 30 min postoperatively. Secondary endpoints included the Short-Form McGill Pain Questionnaire (SF-MPQ) and opioid use in recovery. RESULTS: Of 150 men randomised, 140 were included in the modified intention-to-treat analysis. Moderate-to-severe pain occurred in 22.5% of controls and 8.7% of patients receiving LA (absolute risk reduction 13.8%, 95% confidence interval 2.1-25.6; P = 0.035; number needed to treat = 7). The median VAS and SF-MPQ scores were 0 in both groups. Opioid administration did not differ significantly (10% control vs 19% LA; P = 0.15). In an exploratory post hoc subgroup, the benefit of LA infiltration was greater among men undergoing >20-core biopsy (34.1% vs 10.6%). No significant complications occurred. CONCLUSION: Subcutaneous LA infiltration significantly reduces immediate moderate-to-severe pain following GATP biopsy. Although overall pain scores were low, a clinically meaningful subset benefitted from this simple, low-cost, and safe intervention. These findings also have relevance to contemporary TP prostate biopsy under LA workflows, supporting the concept that superficial infiltration may provide additive value alongside established block-based analgesic protocols.