What is the recommended anesthesia protocol for circumcision?

Anesthesia Preparation for Circumcision

For circumcision procedures, use a dorsal penile nerve root block with lidocaine (maximum 5 mg/kg) or bupivacaine (maximum 2.5 mg/kg), with epinephrine safely added to prolong duration, as this technique most reliably eliminates procedural pain compared to alternative approaches. 1, 2

Patient Population Considerations

Pediatric Patients (Neonates and Children)

• In neonates (≥37 weeks gestational age) and infants, apply lidocaine-prilocaine cream 2.5%/2.5% (EMLA) as a thick layer (1-2 g/10 cm²) to the penile skin for 60 minutes under occlusive dressing prior to performing the dorsal penile nerve block. 3
• Maximum doses for lidocaine-prilocaine cream based on age and weight: 1g for infants 0-3 months (<5kg), 2g for 3-12 months (>5kg), 10g for 1-6 years (>10kg), and 20g for 7-12 years (>20kg). 3
• Do not use lidocaine-prilocaine cream in neonates <37 weeks gestational age or infants <12 months receiving methemoglobin-inducing agents due to risk of methemoglobinemia. 3
• Calculate local anesthetic doses using lean body weight to avoid toxicity. 1

Adult Patients

• For adult male genital skin, apply a thick layer of lidocaine-prilocaine cream 2.5%/2.5% (1 g/10 cm²) for 15 minutes prior to local anesthetic infiltration, then perform the nerve block immediately after cream removal. 3
• Topical anesthesia alone was insufficient as sole anesthetic for genital procedures in 121 adult patients, requiring supplemental infiltration for adequate pain control. 3

Recommended Anesthetic Technique

Dorsal Penile Nerve Root Block (Preferred Method)

• The dorsal penile nerve root block at the penile base is superior to distal branch blocks or subpubic techniques, demonstrating statistically significant pain reduction (P=0.05) with better reliability and safety. 2
• Use 0.5-1% lidocaine (maximum 5 mg/kg without epinephrine, 7 mg/kg with epinephrine) or 0.25% bupivacaine (maximum 2.5 mg/kg). 1
• Epinephrine can be safely added to penile blocks without complications, as demonstrated in clinical studies, and prolongs anesthetic duration by approximately 200%. 4, 1

Ultrasound-Guided Technique (Advanced Option)

• Use a linear ultrasound probe (5-10 MHz frequency) placed transversely at the penile base with gentle penile traction. 5
• The ultrasound-guided in-plane approach reduces local anesthetic volume requirements, decreases narcotic use, and lowers complication rates approximately 2-fold compared to landmark-based techniques. 5

Alternative: Jet Injection (Needle-Free)

• MadaJet injector delivers 0.1 ml of 2% plain lidocaine circumferentially around the proximal third of the penis, with mean total volume of 0.9 ml per procedure. 6
• Anesthetic onset occurs within 45 seconds, and >85% of patients require no supplemental anesthesia. 6
• Mild urethral bleeding occurred in 6.67% of cases but resolved with pressure. 6

Topical Anesthesia Considerations

Efficacy and Limitations

• Topical lidocaine-prilocaine cream alone is insufficient for circumcision pain control but effectively reduces injection pain when used as pretreatment before nerve blocks. 4, 3
• In a randomized trial of 226 participants using ShangRing circumcision, topical anesthesia failed to provide adequate anesthesia in 9.3% before procedure start, and 2.6% required supplemental injectable anesthesia during the procedure. 7
• Despite limitations, topical anesthesia eliminated needlestick pain and resulted in 0% adverse events compared to 4.2% with injectable anesthesia (p<0.01). 7

Application Protocol

• Apply thick layer (not thin application, which is inadequately studied) for specified duration based on procedure type. 3
• Occlusion increases absorption and efficacy; dermal analgesia increases for up to 3 hours under occlusive dressing and persists 1-2 hours after removal. 3

Safety Monitoring and Precautions

Critical Safety Parameters

• Monitor for signs of local anesthetic systemic toxicity (LAST): perioral numbness, tinnitus, seizures, cardiac arrhythmias. 1
• Maximum safe blood levels are typically 1/20 to 1/36 of toxic levels (>5 μg/mL for lidocaine). 3
• In pediatric patients, maintain careful observation to prevent accidental ingestion of topical cream or occlusive dressing; consider secondary protective covering. 3

Contraindications and Special Populations

• Avoid epinephrine in patients with unstable cardiovascular disease; consult cardiology if uncertain. 4
• In pregnant patients requiring circumcision-related procedures, use only topical lidocaine (pregnancy category B); postpone elective procedures until after delivery or at least second trimester. 4
• Patients with hepatic or renal dysfunction may have prolonged half-life of both lidocaine and prilocaine, requiring dose reduction. 3

Common Pitfalls to Avoid

• Never perform distal branch blocks—this technique was discontinued in comparative studies due to concerns about untoward outcomes. 2
• Do not rely on topical anesthesia as sole agent for circumcision; it must be combined with infiltrative techniques for adequate pain control. 3
• Avoid exceeding maximum recommended doses based on patient weight, especially in small children where large treatment areas and prolonged application increase systemic absorption. 3
• Do not use cocaine-containing formulations; noncocaine topical anesthetics are preferred due to lower cost and reduced adverse effects (Strength of Recommendation A, Level of Evidence II). 4