What are the steps for performing a penile block using local anesthetics such as lidocaine (Local Anesthetic) or bupivacaine (Local Anesthetic)?

Penile Block Technique

Perform a dorsal penile nerve block using the subpubic (median) approach with a single midline injection of bupivacaine 0.25-0.5% without epinephrine, supplemented by subcutaneous ring infiltration at the penile base. 1, 2

Patient Preparation and Equipment

• Position the patient supine with the penis retracted cephalad to expose the pubic symphysis 3
• Use a 23-gauge, 1.5-inch needle for the procedure 4
• Consider ultrasound guidance to visualize the dorsal penile nerves in the fascial compartment just deep to Buck fascia, which increases precision and reduces required anesthetic volume 3
• Have lipid emulsion immediately available for treatment of local anesthetic systemic toxicity 1

Local Anesthetic Selection and Dosing

Use bupivacaine 0.25-0.5% without epinephrine as the primary agent. 1, 2

• Maximum safe doses must be calculated before administration: 1

  • Bupivacaine: 1.3 mg/kg without epinephrine (3.0 mg/kg with epinephrine if used)
  • Lidocaine: 4.4 mg/kg without epinephrine (7.0 mg/kg with epinephrine if used)
  • Ropivacaine 0.2%: 2.0 mg/kg without epinephrine (3.0 mg/kg with epinephrine if used)

• A 50:50 mixture of 0.5% bupivacaine and 0.5% lidocaine without epinephrine (maximum 10 mL total) provides both rapid onset and prolonged duration 4

• Add sodium bicarbonate to the local anesthetic solution to reduce injection pain 1

Injection Technique: Subpubic (Median) Approach

Step 1: Midline Subpubic Injection

• Insert the needle perpendicular to the skin in the midline, 0.5-1 cm inferior to the pubic symphysis 2, 3
• Advance the needle through the subcutaneous tissue until you feel a "pop" as it penetrates the superficial fascia 3
• Direct the needle toward the posterior inferior aspect of the symphysis pubis 2
• Always aspirate before injection to avoid intravascular administration 1
• Inject slowly (100-150 seconds for the full dose) to minimize pain—slow injection significantly reduces discomfort compared to rapid injection (40-80 seconds) 5
• The anesthetic will diffuse bilaterally in the subpubic space to block both dorsal penile nerves 2

Step 2: Subcutaneous Ring Infiltration

• After the subpubic injection, perform additional subcutaneous infiltration circumferentially at the penile base 2, 4
• This ring block improves analgesia quality by blocking accessory branches 2
• Inject slowly and aspirate before each injection 5

Alternative: Bilateral Technique

• If using the bilateral approach instead, inject each dorsal penile nerve separately at the "10 o'clock and 2 o'clock" positions at the penile root 3
• However, the bilateral technique is preferred in adults because unilateral injection achieves contralateral diffusion in only 60% of cases, whereas the median technique achieves bilateral spread in 100% of cases 2

Epinephrine Controversy: Critical Safety Consideration

Avoid epinephrine in penile blocks due to the risk of ischemic complications, despite some evidence suggesting safety. 6, 7

• The American Academy of Dermatology states epinephrine "may be considered" for penile procedures (Grade B recommendation, Level II evidence), but this is based on limited retrospective data 6
• A case report documented glans ischemia and penile skin epidermolysis in an 8-year-old after circumcision using lidocaine with epinephrine 7
• The penis has terminal vessel anatomy with limited collateral circulation, making it vulnerable to prolonged vasoconstriction 7
• If you choose to use epinephrine despite these risks, use only the lowest effective concentration and monitor closely for signs of ischemia 6

Onset and Duration

• Expect sensory blockade onset within 5-10 minutes 2
• Postoperative analgesia averages 10 hours with bupivacaine 2
• Test the block adequately before proceeding with surgery to prevent the need for supplemental blocks or general anesthesia 1

Monitoring and Complications

• Monitor for early signs of local anesthetic systemic toxicity: circumoral numbness, facial tingling, slurred speech, tinnitus, and hallucinations 8
• Have resuscitation equipment immediately available 1
• The technique has an excellent safety profile with 93-98% success rates when performed correctly 2, 4
• Inadvertent injection into the corpora cavernosa is a potential complication with landmark-based techniques—ultrasound guidance reduces this risk 3

Common Pitfalls

• Using excessive volumes (up to 50 mL) with landmark-based techniques due to imprecise needle placement—ultrasound guidance allows volume reduction 3
• Rapid injection causes significantly more pain than slow injection (100-150 seconds) 5
• Failing to perform the supplementary ring block at the penile base, which compromises block quality 2, 4
• Not calculating maximum safe dose in mg/kg before administration, risking toxicity 1