Standardised PNB: A PNB will be performed by injection of local anaesthetic around the trunk of the pudendal nerve, which is located behind the sacrospinous ligament. Using transvaginal approach, the ischial spines will be palpated posterolateral to the vaginal sidewall. The sacrospinous ligament is a firm band running medially and posteriorly from the ischial spine to the sacrum. The needle guide with the needle and syringe containing anaesthetic will be inserted so the tip lies against the vaginal mucosa about 1 cm medial and posterior to the ischial spine. When the needle guide gets properly positioned, the needle will be pushed beyond its tip and through the vaginal mucosa into the sacrospinous ligament. After aspirating to confirm the absence of an intravascular location, 3 ml of 0.25% bupivacaine will be injected into the ligament. The needle will then be advanced slightly until the sensation of resistance caused by the ligament is lost. The needle has to be lodged in the loose areolar tissue behind the ligament where the pudendal nerve will be located. Aspiration will again be performed to confirm the absence of an intravascular position (the pudendal and inferior gluteal vessels lie adjacent to the pudendal nerve), and then the remaining 7 mL of anaesthetic are injected. The procedure will be repeated on the contralateral side.