The effect of pudendal block on voiding after hemorrhoidectomy

Urinary retention in common benign anal surgery is a burden to ambulatory surgery. A pudendal nerve block was used in hemorrhoid surgery to reduce voiding complications.

The effects of a pudendal nerve block in anal surgery were compared with those of spinal anesthesia. In this prospective study, 163 consecutive patients who underwent elective hemorrhoids surgery by a single surgeon were randomized to receive pudendal nerve block (pudendal group) with 0.5 percent bupivacaine (n = 81) with 1:20,000 epinephrine or spinal anesthesia (spinal group) with 0.5 percentbupivacaine (n = 82).

There were no statistically significant differences in the patient demographics, total amount of fluid administered, time to the onset of anesthesia, or intraoperative pain. All patients had a successful block during surgery. However, puborectalis muscle relaxation was not complete in the pudendal group. The time from the injection of the anesthetics to the first sensation of pain was longer in the pudendal group (9.1 vs. 3.1 hours; P < 0.001). Urinary catheterization was required in only 6 patients in the pudendal group compared with 57 patients in the spinal group (P < 0.001). The degree of pain was significantly lower in the pudendal group (2.7 vs. 5.2, Visual Analog Scale; P < 0.001). The amount of analgesics injected was significantly lower in the pudendal group (16/81 vs. 45/82; P < 0.001).

A pudendal nerve block with bupivacaine results in fewer postoperative voiding complications and less pain compared with the traditional spinal anesthesia in a hemorrhoidectomy.