Local anesthesia[1] of the penis is used as preparation to perform various procedures, including release of paraphimosis, dorsal slit of the foreskin, circumcision,[2, 3, 4] and repair of penile lacerations. The penis is innervated by the pudendal nerve (S2-S4). This nerve eventually divides into the right and left dorsal nerves of the penis that pass under the pubis symphysis to travel just below the Buck fascia to supply the sensory innervation to the penis. See relevant anatomy in the image below.
The penile shaft is composed of 3 erectile columns, the 2 corpora cavernosa and the corpus spongiosum, as well as the columns' enveloping fascial layers, nerves, lymphatics, and blood vessels, all covered by skin. The 2 suspensory ligaments, composed of primarily elastic fibers, support the penis at its base. For more information about the relevant anatomy, see Penis Anatomy.
The use of parenteral analgesia with or without sedation is recommended before the application of local penile anesthesia.
Indications for anesthesia of the penis include the following:
Dorsal slit of the foreskin
Phimosis reduction
Paraphimosis reduction
Repair of penile lacerations
Release of penile skin entrapped in zippers
Contraindications for anesthesia of the penis include the following:
Suspected testicular torsion
Skin infection at the site of injection
The use of topical anesthetic cream is recommended for all penile procedures.[5]
Eutectic mixture of local anesthetics (EMLA) cream is commonly used.[6]
The cream should be left on the skin area for at least 45 minutes before the planned procedure.
For more information, see Anesthesia, Topical.
Patients who do not achieve adequate anesthesia with the topical application of an anesthetic cream should receive either a local anesthetic infiltration or a penile block.[3]
The following equipment is needed:
Povidone iodine solution (eg, Betadine)
4 x 4 gauze
Local anesthetic solution without epinephrine
Syringe, 5 mL
Needles, 16 and 27 gauge (ga)
The patient should be in the supine position with his genitalia exposed.
After obtaining informed consent from the patient, the healthcare professional should follow these steps:
Have the patient lay supine on a gurney with his genitalia exposed.
Clean gross debris.
Apply a generous amount of povidone iodine solution to the penis and scrotum.
Soak a 4 x 4 gauze pad in povidone iodine solution.
Clean the glans and shaft in a circular motion.
Repeat this step at least 2 more times.
Create a sterile field by placing drapes between the scrotum and the shaft, above the shaft, and on either side.
Administer parenteral analgesia with or without sedation.
See the list below:
Use a 27-ga needle to raise a skin wheal.
Insert the needle subcutaneously through the skin wheal to infiltrate the local anesthetic on both sides of the skin laceration.
See the list below:
Use a 27-ga needle to raise a skin wheal at the base of the foreskin in the dorsal 12-o'clock position.
See the list below:
This technique can be used for anesthesia of complex penile skin lacerations or before attempting to manually reduce paraphimosis.
See the list below:
The right and left dorsal penile nerves should be blocked as proximally to the base of the penis as possible.
Slowly insert the needle through the center of each skin wheal.
The needle should be directed toward the center of the shaft, to a depth of about 0.5 cm or until loss of resistance is felt to suggest that the tip of the needle is within the Buck fascia.
Aspirate to ensure that the needle is not in a blood vessel, and slowly inject about 2 mL of local anesthetic on each side. In neonates and children (< 10 kg), inject 0.2-0.4 mL of lidocaine 1% on each side (10 and 2 o'clock) using a 30-g needle. No more than 4.5 mg/kg should be injected.[7]
Only use anesthetic solutions without epinephrine when administering injectable anesthesia to the penis.[8] Injected anesthetic solutions that contain epinephrine have been associated with penile ischemia and necrosis.
Complications may include the following:
Bleeding and hematomas: Most penile bleeding can be easily controlled with direct pressure.
Failure to achieve adequate anesthesia: A different block should be attempted as long as the toxic dosage of the anesthetic was not exceeded.[9]
Skin sloughing: This complication is more common with distal shaft/glans injections and when anesthetic that contains epinephrine is used.
Infection: The injection site can become infected, but this is rare.[10] A prophylactic antibiotic is not recommended; rather, the patient should be given detailed return precautions.
Overview
What is the anatomy of the penis relevant to dorsal penile nerve block?
What are indications for dorsal penile nerve block?
What are contraindications for dorsal penile nerve block?
What is the role of topical anesthesia in the administration of dorsal penile nerve block?
What equipment is needed to perform dorsal penile nerve block?
How is the patient positioned for a dorsal penile nerve block?
How is the patient prepped for a dorsal penile nerve block?
What is the dorsal penile nerve block approach for penile lacerations?
What is the dorsal penile nerve block approach for dorsal slit of the foreskin?
What is the dorsal penile nerve block approach for complex penile lacerations?
How is a dorsal penile nerve block administered?
What is the role of epinephrine in the administration of dorsal penile nerve block?
What are the possible complications of dorsal penile nerve block?