Thursday, February 10, 2011

How to Block and Tackle the Face

For medical students, residents, or anyone wanting a review, the March 1998 article by Dr. Barry Zide (first full reference below) is a great place to begin.  The article reviews the anatomy of each nerve, the areas of anesthesia obtained by each block, and gives instructions and tips for each of eight facial nerve blocks.   The article, also, has some nice photos.

1.  Infraorbital Nerve

Zide’s preferred technique is the transcutaneous nasolabial approach.

This approach has a point of injection medial to the upper nasolabial groove a few millimeters lateral to the alar groove. The injection point for the infraorbital nerve is in the center of the small triangle lateral to the alar rim and medial to the nasolabial fold. With your left index finger on the infraorbital rim, ask the patient to look straight ahead. Holding the syringe like a pen, you advance the needle to bone toward the designated point about 4 to 7 mm down from the rim. Often, the needle tip goes directly into the foramen itself. If you wish to inject the foramen, you may have to poke around for a couple of millimeters, but you will always be able to enter into the foramen this way. Then, inject 1 to 2 cc. There is a 100-percent success rate using this external block approach, and the senior author has never seen a neuritis from this or any of the three methods.

2.  Mental and Mental Plus

The mental nerve can be blocked at the mental foramen or a few centimeters after it leaves the foramen submucosally.

To block it at the foramen, locate the second lower bicuspid. Place the needle tip in the buccal sulcus near the base of the tooth and inject. The nerve itself is not covered by muscle after it leaves the foramen, just a thin layer of mucosa and perineural sheath. Often, the nerve can be palpated at the foramen or in the first few centimeters of its course. If the surgeon desires, he can inject away from the foramen by finding the upper fascicles visually or tactilely. Use the thumb of one hand to pull out the lower lip, lateral to the lower canine tooth. By squeezing the lip and sliding the thumb outward, the nerve is visible submucosally about 85 percent of the time.

Mental Plus block will also anesthetize the chin by blocking  an end branch of the mental nerve and the terminal branches of the mylohyoid.

These can be done immediately after the mental block by an anterior premandibular injection anterior to the vestibule in front of the anterior teeth.  You must change your position to behind the patient, turn the syringe more vertically, and inject in the supraperiosteal plane with at least a 1.5-inch needle. You must inject anterior to and beyond the lower border of the mandible (actually out on the lip) but not quite out of the skin. Only the mental plus block obviates the need for the inferior alveolar block (i.e., regardless of whether the mental nerve or mylohyoid nerve supplies the chin).

3.  Supraorbital/Supratrochlear/Infratrochlear

4.  Dorsal Nasal Nerve

5.  Zygomaticotemporal

6.  Zygomaticofacial

7.  Great Auricular

Have the patient flex the sternocleidomastoid muscle by pushing the head against a hand placed on the ipsilateral forehead. This maneuver will outline the sternocleidomastoid muscle against the neck skin. Mark the skin of the upper anterior and posterior sternocleidomastoid borders with two parallel lines. Then draw a third line between the first two parallel lines directly in midmuscle. Measure down 6.5 cm from the lower border of external acoustic meatus to the mid-sternocleidomastoid. A useful template is a measurement from your own hand. For example, 6.5 cm is the measurement of my baby finger tip to the webspace or my thumb metacarpophalangeal to tip. Inject a nickel to quarter sized circle of anesthetic onto the muscle fascia at this intersection

8.  V3 Block

 

I have included several other good references for you below.

 

 

REFERENCE

How to Block and Tackle the Face; Zide, Barry M.; Swift, Richard; Plastic & Reconstructive Surgery. 101(3):840-851, March 1998

Addendum To "How To Block and Tackle the Face"; Zide, Barry M.; Swift, Richard; Plastic & Reconstructive Surgery. 101(7):2018, June 1998.

Regional Anesthesia on the Lacrimal Nerve; Ross, Gary; Taams, Karl; Plastic & Reconstructive Surgery. 104(3):876-878, September 1999.

Nerve Block, Infraorbital; eMedicine Article, Updated: May 19, 2010;  Karen M Byrne, MD 

Regional Anesthesia for Office Procedures: Part I. Head and Neck Surgeries; Gohar Salam, MD, DO;Am Fam Physician 2004 Feb 1;69(3):585-590

Local Anesthesia Techniques in Oral and Maxillofacial Surgery; Sean M. Healy, D.D.S., Francis B. Quinn, M.D.; University of Texas Medical Branch Grand Rounds, October 2004  (pdf)

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