Facial Nerve Blocks

To anesthetize portions of the face and ears

Areas of distributions:

Supraorbital and supratrochlear: Forehead

Infraorbital: Upper lip, upper cheek, lateral portion of the nose, and anterior maxillary teeth

Inferior alveolar: Lower jaw, lower lip, lower teeth, and anterior two-thirds of the tongue

Mental: Lower jaw, lower teeth, anterior tongue, and floor of the mouth

Auricular: External ear

CONTRAINDICATIONS

Absolute Contraindications

Anaphylaxis to local anesthetic agents

Relative Contraindications

Coagulopathy

Infection at the injection site

Uncooperative or obtunded patients

SUPPLIES

25-gauge to 30-gauge needle

Syringe

Topical anesthetic (optional)

Eutectic mixture of local anesthetics (EMLA), 20% benzocaine, or 5% to 10% lidocaine ointment can be used to decrease the pain of needle insertion

Bicarbonate (optional)

1:10 dilution with injectable anesthetic to decrease the pain of infiltration

Anesthetic agent

Lidocaine 1% to 2%

Onset of action: 4 to 10 minutes

Duration of action: 1 to 2 hours

Maximum one time dose: 4.5 mg/kg

Bupivacaine 0.25%

Onset of action: 8 to 12 minutes

Duration of action: 4 to 8 hours

General Basic Steps

Preparation

Identify landmarks

Injection of anesthetic

PREPARATION

Position patient and adjust lighting for optimal visualization

Apply topical local anesthetic

Prepare nonmucosal injection sites with povidone–iodine solution or chlorhexidine

Use sterile gloves

LANDMARKS AND TECHNIQUES

Forehead Nerve Block (Supraorbital and Supratrochlear Nerve Blocks)

Locate the supraorbital notch which is at the intersection of the superior edge of the orbit and a vertical line through the middle of the pupil when the eyes are looking forward

Insert the needle slightly superior and medial to the supraorbital notch and inject 2 to 4 mL of anesthetic

Move 0.5 to 1.0 cm medially and inject an additional 2 to 4 mL of anesthetic to block the supratrochlear nerve (FIGURE 80.1)

Infraorbital Nerve Block

Locate the infraorbital foramen which is at the intersection of the inferior edge of the orbit and a vertical line through the middle of the pupil when the eyes are looking forward

Extraoral or intraoral approaches can be used

Extraoral

Insert the needle 1 cm below the infraorbital foramen and inject 2 to 4 mL of anesthetic

Intraoral

Place one finger on the infraorbital foramen and retract the upper lip

Identify the first maxillary premolar and insert the needle into the mucobuccal fold with the bevel facing the bone

Advance the needle toward the apex of the tooth or 1 cm below the infraorbital foramen

Take caution to avoid entering the orbit or the infraorbital foramen. If the patient feels paresthesias, retract the needle.

Inject 2 to 4 mL of anesthetic

Mental Nerve Block

Locate the mental foramen which lies in the plane of the supraorbital and infraorbital foramina (see above) at the apex of the lower second premolar

Extraoral or intraoral approaches can be used (FIGURE 80.2)

Extraoral

Insert the needle 1 cm inferolateral to the foramen

Inject 2 to 4 mL of anesthetic

Intraoral

Retract the patient’s lower lip

Locate the space between the premolar and molar teeth

FIGURE 80.1 The supraorbital and supratrochlear nerves emerging through the notches at the upper border of the orbital ridge. (From Simon RR, Brenner BE. Emergency Procedures and Techniques. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2002:117, with permission.)

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