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Patient selection plays a major role in performing the block; it is challenging with obese patients.
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Ultrasound experience is required to maximize the success rate of the block.
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Vascular injection is a risk if no spread is visualized with deposition of local anesthetics under ultrasound.
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Avoid contamination as the area of injection is close to the perianal area.
Indications
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Perineal operations in both sexes.
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Hypospadias and circumcision are the most common surgeries.
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Scrotal and testicular surgeries with a supplementation of ilioinguinal blockade.
Contraindications
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Infection or presence of perianal inflammation.
Sonoanatomy
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The pudendal nerve derives its fibers from the ventral branches of the second, third, and fourth sacral nerves. It leaves the pelvis through the lower part of the greater sciatic foramen, passes behind the spine of the ischium, and reenters the pelvis through the lesser sciatic foramen. It accompanies the internal pudendal vessels along the medial border of the ischial tuberosity ( Fig. 46.1 ).
