Pudendal Nerve Block

First reported by King in 1916 for pain control during the second stage of labor, pudendal nerve block is commonly performed by obstetrician in patients without spinal or epidural analgesia.
The pudendal nerve carries somatic nerve fibres from the anterior primary divisions of the second, third and fourth sacral nerves.
The technique aims at blocking the nerve distal to its formation but proximal to its division into its terminal branches (i.e., dorsal nerve of the clitoris, perineal nerve and inferior haemorrhoidal nerve) .
The technique is based on bilateral injection of 10 ml of local Anesthetic solution medial and posterior to the ischael spine after introducing the needle through vaginal mucosa and sacrospinous ligament.
Another percutaneous approach has been described but it is less commonly applied.
Careful aspiration is a must as pudendal artery lies in close proximity to the nerve1.
Complications include systemic toxicity, laceration of vaginal mucosa, vaginal and ischeorectal haematoma and subgluteal abscess.
As paracervical block, direct injection into foetal tissues and needle-stick injuries are a potential risk.
Pudendal nerve block may provide satisfactory analgesia for spontaneous vaginal delivery an outlet forceps delivery but it is entirely inadequate for mid forceps delivery, cervical repair and manual examination of the uterus .