What is a supraorbital nerve block?
A supraorbital nerve block is a procedure to provide regional anesthesia to the area of the face from the upper eyelid to the top of the head. An anesthetic solution is injected at a point in the eyebrow where the supraorbital nerve exits the skull to numb the upper eyelid, forehead and the frontal part of the scalp.
What does the supraorbital nerve do?
The supraorbital nerve forms a part of the ophthalmic nerve, which is one of the branches of the trigeminal nerve. The trigeminal nerve provides sensation to the face. The trigeminal nerve has three main branches:
- Ophthalmic nerve: Provides sensation to the top of the nose, upper eyelids and the forehead.
- Maxillary nerve: Provides sensation to the sides and septum of the nose, cheeks, and upper portion of the mouth and jaw.
- Mandibular nerve: Provides sensation to the temples, front of the ears, tongue and the lower portion of the mouth and jaw.
The supraorbital nerve and the supratrochlear nerve form the frontal branch of the ophthalmic nerve. The supraorbital nerve and the supratrochlear nerves together provide sensation to the frontal scalp, forehead, upper eyelid and the root of the nose.
Why is a supraorbital nerve block performed?
Supraorbital nerve block is performed to anesthetize the part of the face this nerve innervates, for treatment procedures such as:
- Closing lacerations or wounds
- Removal of foreign bodies
- Removal of damaged tissue (debridement) from burns or abrasions
- Relief for acute pain from shingles (Herpes zoster)
- Pain relief from migraine
- Pain management after a surgical procedure (an adjunct or alternative opioid use)
A supraorbital nerve block may be avoided in the case of:
- Infection in the injection site
- Known allergy to the anesthetic agent
- Distortion in the anatomical part
The supraorbital nerve block is preferred over a local tissue infiltration of anesthesia because of advantages including:
- Rapid anesthetic effect providing immediate pain relief
- Anesthesia of a larger area with minimal quantity of anesthetic agent
- Lack of risk for tissue distortion unlike tissue infiltration anesthesia
How is a supraorbital nerve block performed?
A supraorbital nerve block is performed in the physician’s office or the emergency room. Depending on the required duration of anesthesia, the doctor may use 1 mm-2 mm of one of the following anesthetic agents:
- The patient may be seated or lying flat for the procedure.
- The injection site is sterilized with antiseptic solution.
- Uses his fingers around the eyebrow to find the hole (foramen) in the bone (supraorbital ridge) where the supraorbital nerve comes out of the eye socket (orbit).
- Inserts the needle and injects a small quantity of the anesthetic agent to raise a bump (wheal) in the area.
- Presses a roll of gauze over the eyelid to prevent the anesthetic swelling into the eyelid.
- Inserts the needle in the wheal, close to the foramen taking care to avoid entering the foramen.
- Aspirates the syringe to ensure that the needle is not inside a blood vessel.
- Injects the anesthetic agent slowly and withdraws the needle.
- Waits for up to 10 minutes for the anesthesia to take effect.
- If the nerve block is unsuccessful, the doctor may administer several injections (field block) along the supraorbital rim, anesthetizing all the branches of the ophthalmic nerve.
If the needle tip is in the correct position and the anesthetic is injected slowly, there should be only minimal pain with the needle insertion.
How long does a supraorbital nerve block last?
It is difficult to predict the duration of the supraorbital nerve block effect. Some people find almost immediate pain relief from migraine or shingles, lasting up to six weeks, while some may find no benefit.
The duration of a supraorbital nerve block’s effect used to perform a procedure significantly depends on the type of anesthetic agent used. The approximate periods of anesthetic effect are as follows:
- Lidocaine: up to 75 minutes
- Tetracaine: up to three hours
- Bupivacaine: up to eight hours
The patient may experience tingling, discomfort or pain as sensation starts returning to the area. Post-procedure pain may be relieved with painkillers.
What are the risks and complications of a supraorbital nerve block?
Supraorbital nerve blocks are usually safe and carry minimal risks. The complications include: