Pudendal Nerve Block

Pudendal Nerve Block

A. Indications

Pudendal nerve block is useful in evaluating patients with perineal somatosensory pain.

B. Anatomy

The pudendal nerve arises from S2–S4 and courses between the sacrospinous and the sacrotuberous ligaments to reach the perineum.

C. Technique

This block is usually performed transperineally with the patient in the lithotomy position ( Figure 47–19) although it may be performed via a posteriorapproach in the prone position. Injection of anes-thetic is carried out percutaneously just posterior to the ischial spine at the attachment of the sacro-spinous ligament. The ischial spine can be palpated transrectally or transvaginally. Alternatively, this procedure may be performed in the prone position with a 22-gauge needle directed toward the base of

the ischial spine. Patients should be advised that they may have numbness of the genitalia for hours after this procedure is performed.

D. Complications

Potential complications include unintentional sci-atic blockade and intravascular injection.