Overview
Anesthesia of the ear is useful for repair of lacerations, hematoma incision and drainage, and other painful procedures of the ear.
Anatomy
The ear is composed of 3 compartments: the external ear, the middle ear, and the inner ear. For the purpose of local anesthesia, this article focuses on the external ear, which comprises the auricle, or pinna, and ear canal. The auricle (visible part of ear) is composed mainly of cartilage covered by skin and consists of the helix, antihelix, lobule, tragus, and concha.
Anatomy of the ear is shown below.
Anatomy of the ear. Four sensory nerves supply the external ear: (1) greater auricular nerve, (2) lesser occipital nerve, (3) auricular branch of the vagus nerve, and (4) auriculotemporal nerve. Knowledge of the nerve anatomy is critical in understanding anesthesia of the ear. For more information about the relevant anatomy, see Trigeminal Nerve Anatomy, Facial Nerve Anatomy, and Vagus Nerve Anatomy.
Anatomy of the sensory nerves of the external ear are shown in the image below.
Anatomy of sensory nerves in the external ear. - The greater auricular nerve is a branch of the cervical plexus. It innervates the posteromedial, posterolateral, and inferior auricle.
- The lesser auricular nerve innervates a small portion of the helix.
- The auricular branch of the vagus nerve innervates the concha and most of the area around the auditory meatus.
- The auriculotemporal nerve is a branch of the mandibular branch of the trigeminal nerve. It innervates the anterosuperior and anteromedial aspect of the auricle.
- The external auditory canal and tympanic membrane have separate innervation. Indications for anesthetizing these areas are distinct from those for performing an auricular block.
For more information about the relevant anatomy, see Ear Anatomy.
Indications
- Suture of a large laceration of the ear or the skin surrounding the ear[1]
- Painful procedures of the ear, such as incision and drainage of an abscess or hematoma[2] (For more information, see eMedicine article Drainage, Auricular Hematoma.)
Contraindications
- Cellulitic periauricular skin
- Severe allergy to the chosen anesthetic
Anesthesia
- Local anesthetic agents (eg, lidocaine 1% [Xylocaine], bupivacaine 0.25% [Marcaine]) may be used.
- If a regional block is performed, lidocaine with epinephrine can be used; however, epinephrine is contraindicated in direct infiltration of the ear.[3]
- For more information, see Local Anesthetic Agents, Infiltrative Administration and Local Anesthesia and Regional Nerve Block Anesthesia.
Equipment
- Syringe, 5-10 mL
- Needle, 25 or 27 gauge
- Parenteral anesthetic agent
- Light source
Positioning
- Position the patient so that both clinician and patient are comfortable and the ear to be anesthetized is easily accessible.
- Supine is usually the optimal position.
Technique
The choice of technique depends on the area of the ear that requires anesthesia.
Ring block technique
The ring block, shown in the image below, provides anesthesia to the entire ear, excluding the concha and external auditory canal.
Ring block technique. - Disinfect skin with an alcohol swab.
- Insert the needle into the skin just inferior to the attachment of the earlobe to the head. Do not insert the needle into the earlobe itself. Direct the needle toward the tragus.
- Aspirate and then inject 3-4 mL of anesthetic while advancing the needle in a superior direction.
- Withdraw the needle but do not remove it. Redirect the needle posteriorly along the inferior posterior auricular sulcus.
- Aspirate and inject anesthetic while advancing the needle.
- Remove the needle and reinsert it just superior to the attachment of the helix to the scalp. Direct the needle anteriorly, toward the tragus, and aspirate before injecting anesthetic. Advance the needle while injecting. Inject the subcutaneous tissue, not the ear cartilage.
- Withdraw the needle but do not remove it. Redirect the needle posteriorly; aim toward the skin just behind the mid ear. Aspirate and inject anesthetic while advancing the needle.
- Be aware that the superficial temporal artery, located medial to the ear, crosses over the zygomatic arch. If the artery is cannulated, maintain firm pressure with gauze for at least 20-30 minutes.
Field block technique
This field block, depicted below, provides anesthesia to the earlobe and lateral helix (greater auricular and less occipital nerves).
Technique to anesthetize the earlobe and lateral helix. - Disinfect the skin with an alcohol swab.
- Insert the needle behind the inferior aspect of the earlobe. Aspirate and inject 3-4 mL of anesthetic while advancing the needle superiorly, following the curve of the posterior sulcus. Ear anesthesia. Courtesy of Hamid R Djalilian, MD.
Auriculotemporal nerve block
This technique, shown in the image below, provides anesthesia to the helix and tragus (auriculotemporal nerve).
Technique to anesthetize the helix and tragus. - Disinfect the skin with an alcohol swab.
- Insert the needle superiorly and anteriorly to the tragus.
- Aspirate and inject 2-4 mL of anesthetic.
Pearls
- Since adequate anesthesia of the auditory canal and tympanic membrane is difficult to obtain, consult an ENT specialist for painful procedures involving these areas.
- Do not inject cellulitic skin.
- Do not inject any anesthetic containing epinephrine directly into the ear itself.
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Giles WC, Iverson KC, King JD, Hill FC, Woody EA, Bouknight AL. Incision and drainage followed by mattress suture repair of auricular hematoma. Laryngoscope. Dec 2007;117(12):2097-9. [Medline].
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Head S, Enneking FK. Infusate contamination in regional anesthesia: what every anesthesiologist should know. Anesth Analg. Oct 2008;107(4):1412-8. [Medline].
Brull R, McCartney CJ, Chan VW, Liguori GA, Hargett MJ, Xu D, et al. Disclosure of risks associated with regional anesthesia: a survey of academic regional anesthesiologists. Reg Anesth Pain Med. Jan-Feb 2007;32(1):7-11. [Medline].
Riviello RJ. Otolaryngologic Procedures. In: Roberts JR, Hedges JR, eds. Clinical Procedures in Emergency Medicine. 4th ed. Philadelphia, Pa: WB Saunders; 2004:1287-9.
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