Infraorbital Nerve Block for Upper Lip Anesthesia
For upper lip anesthesia, use an intraoral approach to the infraorbital nerve block with 1.8-2.5 mL of 2% lidocaine with 1:100,000 epinephrine, injecting at the infraorbital foramen located at the intersection of a vertical line through the pupil and a horizontal line through the ala of the nose.
Technique Selection
The intraoral approach is superior to the percutaneous (extraoral) approach for upper lip anesthesia. While both techniques can provide adequate anesthesia, the intraoral route demonstrates longer duration of anesthesia (1.6 hours vs 0.9 hours) and higher success rates for upper lip anesthesia (100% vs 75%) 1. Additionally, the extraoral approach causes more needle insertion pain and postoperative complications 2.
Step-by-Step Technique
Preparation
- Apply topical anesthetic (viscous lidocaine) to the oral mucosa for 1 minute before injection to minimize discomfort 1
- Use a 27-gauge needle 1
Landmark Identification
Locate the infraorbital foramen at the intersection of:
- Vertical line: Through the pupil with the eye in neutral position
- Horizontal line: Through the ala of the nose 3
The foramen is typically 5-10 mm below the infraorbital rim.
Injection Approach (Intraoral)
- Retract the upper lip and identify the canine fossa
- Insert the needle through the mucobuccal fold above the first premolar
- Direct the needle superiorly, laterally, and posteriorly toward the infraorbital foramen
- Palpate the infraorbital rim extraorally with your non-dominant hand to guide needle placement
- Advance until you contact bone near the foramen (do NOT enter the foramen itself)
- Aspirate before injection to avoid intravascular administration 4
- Inject 1.8-2.5 mL of anesthetic solution slowly over 20 seconds 1, 2
Anesthetic Selection and Dosing
Recommended Solution
2% lidocaine with 1:100,000 epinephrine is the standard choice 1, 2
Dosing Limits
- Adults: Maximum 7.0 mg/kg lidocaine with epinephrine 4
- Children: Maximum 3.0-4.5 mg/kg lidocaine with epinephrine 4
For a typical 2.5 mL injection of 2% lidocaine (50 mg total), this represents a safe dose for adults >7 kg and children >11-17 kg.
Alternative Anesthetics
For longer duration procedures:
- 0.25-0.5% bupivacaine with 1:200,000 epinephrine provides 6-24 hours of postoperative analgesia 3, 5
- 0.2% ropivacaine is effective with good hemodynamic stability 6
Expected Outcomes
Onset and Duration
- Onset: Similar for both intraoral and extraoral approaches (typically 3-5 minutes)
- Duration: 1.6 hours average with lidocaine 1; up to 8 hours with bupivacaine 7
Area of Anesthesia
The infraorbital nerve block anesthetizes:
- Upper lip (most reliable)
- Lower eyelid
- Lateral nose
- Anterior cheek
Important caveat: This block is ineffective for the central and lateral incisors (only 15-22% success rate) 2. For procedures involving these teeth, supplemental infiltration anesthesia is required.
Success Rates by Tooth
- Canine: 92% 2
- Premolars: 80-90% 2
- First molar: 65-70% 2
- Central/lateral incisors: 15-22% (inadequate) 2
Safety Considerations
Critical Safety Steps
- Always aspirate before injection to avoid intravascular administration 4
- Use incremental injections 4
- Monitor for early signs of toxicity: circumoral numbness, facial tingling, metallic taste, tinnitus 4
- Use the lowest effective dose 4
Common Pitfalls to Avoid
- Do not inject into the infraorbital foramen itself - this can cause nerve injury
- Do not rely on this block alone for incisor procedures - supplement with infiltration
- Avoid in patients with active facial infection 1
- Do not use in patients with bee sting allergy if hyaluronidase is added 4
Adjuncts to Reduce Pain
Buffer the lidocaine with sodium bicarbonate (1:9 or 1:10 ratio of 8.4% bicarbonate to lidocaine) to reduce injection pain by 20-40% 4. Mix immediately before use and use within a reasonable timeframe to prevent epinephrine precipitation.