Ear Anesthesia

Ear Anesthesia

Direct local injection of a laceration on the ear itself can distend margins near the cartilage, making approximation all the more difficult.  Alternatively, one might consider a nerve block.  This works well for various regions of the face, such as the infraorbital nerve block for lacerations below the eye.  However, the ear is innervated by multiple cranial nerve branches and cervical nerve roots.  Thus, trying to block all of them is an exercise in futility.  Rather, field block–eg local anesthetic surrounding the ear to catch all of the small branches of the nerve supply–is the way to go. Anesthesia of the ear is useful for repair of lacerations, hematoma incision and drainage, and other painful procedures of the ear.

Anatomy of the ear

Innervasion of ear

1.The greater auricular nerve is a branch of the cervical plexus. It innervates the posteromedial, posterolateral, and inferior auricle (lower two-thirds both anteriorly and posteriorly).

2. The lesser occipital nerveinnervates a small portion of the helix.

3. The auricular branch of the vagus nerveinnervates the concha and most of the area around the auditory meatus.

4. The auriculotemporal nerveoriginates from the mandibular branch of the trigeminal nerve. It innervates the anterosuperior and anteromedial aspects of the auricle.

5. The external auditory canal and tympanic membrane have separate innervation. Indications for anesthetizing these areas are distinct from those for performing an auricular block.

Indications

Anesthetizing the ear may be required in the following situations:

• 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, 3]} (For more information, see Medscape Reference article Auricular Hematoma Drainage.)

Contraindications

Avoid anesthetizing the ear if the patient has cellulitic periauricular skin or a 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 mixed with epinephrine can be used; however, epinephrine is contraindicated in direct infiltration of the ear. ^[4]

Equipment

The following equipment is needed:

• Syringe, 5-10 mL
• Needle, 25-gauge or 27-gauge (5-7 cm in length)
• 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. Laying the patient supine is usually the optimal position.

Technique

The choice of technique depends on the area of the ear that requires anesthesia.

1. Ring block technique

2. Field block technique

3. Auriculotemporal nerve block

1.Ring block technique

The ring block, shown in the image below, provides anesthesia to the entire ear, excluding the concha and external auditory canal.

Steps for this technique are as follows:

                     1.Disinfect skin with an alcohol swab.

2. 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. Advance the needle just anterior to the tragus, aspirating as the needle advances.
3. Aspirate and then inject 2-3 mL of anesthetic while withdrawing the needle slowly back toward the puncture site without removing it.
4. Once just under the skin at the puncture site, redirect and advance the needle posteriorly along the inferior posterior auricular sulcus, aspirating as it is advanced.
5. Aspirate and inject 2-3 mL of anesthetic while withdrawing the needle.
6. Remove the needle and reinsert it just superior to the attachment of the helix to the scalp. Direct and advance the needle just anterior to the tragus, aspirating as it is advanced.
7. Aspirate and inject 2-3 mL of anesthetic while withdrawing the needle toward your puncture site without removing it. Remember to inject the subcutaneous tissue, not the ear cartilage.
8. Once just under the skin at your puncture site, redirect and advance the needle posteriorly along the superior posterior auricular sulcus, aspirating as it is advanced.
9. Aspirate and inject 2-3 mL of anesthetic while withdrawing the needle.
10. 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.

2. Field block technique

This field block, depicted below, provides anesthesia to the earlobe and lateral helix (greater auricular and lesser occipital nerve branches).

Steps for this technique are as follows:

              1.       Disinfect the skin with an alcohol swab.

2. Insert the needle just posterior to the inferior attachment of the the auricle (behind the earlobe). Aspirate and inject a total of 3-4 mL of anesthetic while advancing the needle superiorly, following the curvature of the posterior sulcus. See the video below.

3.       Auriculotemporal nerve block

This technique, shown in the image below, provides anesthesia to the helix and tragus (auriculotemporal nerve).

Steps for this technique are as follows:

              1.       Disinfect the skin with an alcohol swab.

2. Insert the needle anteriorly and superiorly to the tragus.
3. Aspirate and inject 3-4 mL of anesthetic.

Complications

Complications may include the following:

1. Infection ^[5]

2. Allergic reactions

3. Inadequate anesthesia ^[6]

4. Cannulation of the superficial temporal artery 

Reffer

1. Brown DJ, Jaffe JE, Henson JK. Advanced laceration management. Emerg Med Clin North Am. 2007 Feb. 25(1):83-99. [Medline].

2. Giles WC, Iverson KC, King JD, Hill FC, Woody EA, Bouknight AL. Incision and drainage followed by mattress suture repair of auricular hematoma. Laryngoscope. 2007 Dec. 117(12):2097-9. [Medline].

3. Shakeel M, Vallamkondu V, Mountain R, Hussain A. Open surgical management of auricular haematoma: incision, evacuation and mattress sutures. J Laryngol Otol. 2015 May. 129 (5):496-501. [Medline].

4. DeBoard RH, Rondeau DF, Kang CS, Sabbaj A, McManus JG. Principles of basic wound evaluation and management in the emergency department. Emerg Med Clin North Am. 2007 Feb. 25(1):23-39. [Medline].

5. Head S, Enneking FK. Infusate contamination in regional anesthesia: what every anesthesiologist should know. Anesth Analg. 2008 Oct. 107(4):1412-8. [Medline].

6. 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. 2007 Jan-Feb. 32(1):7-11. [Medline].

7. Riviello RJ, Brown NA. Otolaryngologic Procedures. Roberts JR, Hedges JR, eds. Clinical Procedures in Emergency Medicine. 5th ed. Philadelphia, PA: WB Saunders; 2010. 1187-98.