Overview of Supraorbital Nerve Block
A supraorbital nerve block is a procedure used to numb a specific area of the face, especially the forehead and upper eyelid. This treatment might be used for several reasons, including treating severe cuts on the forehead, fixing cuts on the upper eyelid, cleaning wounds or burns on the forehead, removing foreign objects stuck in the skin, or reducing pain from acute herpes zoster, which is a painful rash caused by the same virus that causes chickenpox.
This type of numbing, called a regional block, is beneficial because it uses a small amount of numbing medication to affect a large area of the skin. This means there is less chance that the medication will spread into other tissues and potentially distort the normal structure of the skin during the procedure.
This procedure needs to be done by someone who understands where certain points on the body, known as anatomical landmarks, are located. It also requires only a minimal amount of special medical equipment.
Anatomy and Physiology of Supraorbital Nerve Block
The understanding of the correct bodily structure involved is very important when carrying out a medical procedure since it relies on anatomical landmarks. One such landmark is the supraorbital nerve, which is a branch of the trigeminal nerve. The trigeminal nerve itself splits into three branches: the ophthalmic nerve (V1), the maxillary nerve (V2), and the mandibular nerve (V3).
The supraorbital nerve, part of the ophthalmic nerve, splits into two essential branches – the smaller supratrochlear nerve and the larger supraorbital nerve. This nerve exits the skull through a natural hole above the eye socket known as the supraorbital notch or supraorbital foramen and continues up the forehead. The nerve ends in the front of the scalp, providing feeling to the tissues in that area.
The supratrochlear nerve provides feeling in a small area near the middle of the forehead. You can see the supraorbital foramen by having the patient look straight ahead and drawing an imaginary line through the pupil and the patient’s brow ridge. When this area is gently pressed, it outlines the spot for applying a nerve block – a technique to control pain.
Among the people studied, most supraorbital nerve exits were notches (73.8%), while the rest were foramina (26.2%). Some people had extra exits (18.9%), and others had a notch on one side and a foramen on the other (36.3%).
After it leaves the eye socket area, the supraorbital nerve splits into two divisions: (1) a superficial (medial) division that goes over the forehead muscle, providing feeling to the skin of the forehead and the front edge of the scalp; and (2) a deep (lateral) division that runs across the side of the forehead, providing feeling to the front and top of the scalp.
People with supraorbital neuralgia experience pain, tenderness, reduced feeling, and sensitive skin in the area covered by the affected nerve. Fractures in the bones around the eye, blunt facial trauma, tumors in the eye socket, and tight swimming goggles or motorcycle helmets can cause the supraorbital nerve to become trapped.
Why do People Need Supraorbital Nerve Block
A supraorbital nerve block is a medical procedure often used to manage pain or prepare for certain surgeries. The supraorbital nerve is found in your forehead, so this method is used for procedures on your forehead or the front of your scalp. This might be needed in a range of scenarios, including:
- Cleaning out burns or scrapes on the skin.
- Providing immediate pain relief for shingles, which is a painful rash caused by the same virus that causes chickenpox.
- Easing itchiness that can persist after a shingles outbreak.
- Repairing complicated cuts on the skin.
- Removing foreign objects that might have gotten lodged in the skin.
- Managing episodes of migraines, which are severe headaches often accompanied by nausea and sensitivity to light or sound.
Additionally, a supraorbital nerve block can also be used for managing different types of head and face pain, such as trigeminal neuralgia and hemicrania continua, which are specific types of chronic headache disorders. It can also be beneficial in cluster headaches that occur in cyclical patterns or clusters.
Also, it can be used as part of the preparation for various surgeries like:
- Eye surgeries, such as upper eyelid surgery or oculoplastic surgery (a procedure that involves the reconstruction of the eye).
- Trabeculectomy, a type of eye surgery used to treat glaucoma, a condition that damages your eye’s optic nerve.
- Awake craniotomy, a surgery performed while a patient is awake to remove a brain tumor.
- Placement of cranial fixation and stereotactic frames, which are used in certain types of brain surgery to keep the patient’s head still.
- Dermatologic or oncologic procedures, which are treatments related to skin conditions or cancer.
When a Person Should Avoid Supraorbital Nerve Block
A supraorbital nerve block is a medical procedure that numbs the forehead and scalp area. However, there are a few conditions that may prevent it from being performed:
– If the patient doesn’t agree to the procedure
– If the usual physical features or structures (anatomical landmarks) in the area where the procedure is to be performed are abnormally shaped or positioned
– If there is an infection on the skin where the injection needs to be given
– If the patient has an allergic reaction to the local anesthetic, a medicine design to numb that specific area.
Equipment used for Supraorbital Nerve Block
To carry out the supraorbital nerve block, a type of local anesthesia, the doctor will need several items:
* Anesthetic drug: The doctor’s choice of this drug will depend on any allergies you’ve reported and how long they want the anesthesia to last. Options include lidocaine, which works for up to 90 minutes, bupivacaine, which lasts up to 8 hours, and tetracaine, which works up to 3 hours.
* If you’re allergic to certain types of local anesthetics, they might use a drug called diphenhydramine.
* A needle is used to deliver the anesthetic. For adults, a 25 gauge (ga) needle is used and for children, a 30 ga needle is used.
* A syringe, which can hold between 5-10 mL, is used to contain the anesthetic drug.
* Before injection, your skin will be cleaned with substances such as chlorhexidine or betadine to reduce the risk of infection.
* In rare instances, anesthetic can spread within the body more than intended. If this happens, a substance called a lipid emulsion can be used to reverse the effects.
* An ultrasound machine might be used to help guide the injection to the correct spot. This isn’t always necessary, but can improve precision in some cases.
Preparing for Supraorbital Nerve Block
Before starting a medical procedure that involves numbing an area on your forehead (a supraorbital nerve block), the doctor will explain what the procedure involves, its risks, and benefits. It’s important that you understand this information and give your agreement for the procedure to go ahead.
The doctor will prepare everything needed for the operation in the room. He or she will use one of two types of pain-numbing medicine, either lidocaine or bupivacaine. These medicines can be given alone or with a medication called epinephrine that helps the numbing effect last longer. But, there’s a limit to how much of these medicines can be used safely.
So, if your doctor uses lidocaine with epinephrine, you’ll get up to 7 milligrams (mg) of lidocaine for each kilogram (kg) of your body weight, but no more than 500 mg in total. If the lidocaine is given without epinephrine, you can receive up to 4.5 mg/kg, but not more than 300 mg in total.
If your doctor chooses to use bupivacaine with epinephrine, you can get up to 3 mg/kg, with an utmost limit of 225 mg for one dose, and no more than 400 mg in 24 hours. If the bupivacaine is given without epinephrine, you can receive up to 2.5 mg/kg, with an utmost limit of 175 mg for one dose, and no more than 400 mg in 24 hours.
How is Supraorbital Nerve Block performed
The supraorbital nerve block procedure is a type of treatment that can help with pain relief by numbing certain areas of your body, in this case, the forehead area. Here’s a simple step-by-step guide:
First, the doctor needs to locate specific points on your body – this is what medical professionals call identifying appropriate landmarks.
The doctor will then clean the area where the injection will be made. A special, germ-killing cleansing agent will be used to make sure the area is sterile. This process is known as using an aseptic technique.
You will be asked to lie flat on your back, or in what doctors call a supine position.
The doctor will then insert a very thin needle, about the size of a thick human hair, into the lower edge of the ridge just above your eyebrow (the supraorbital ridge). This will be done just below the small notch along this ridge that’s about half a centimeter from the lower edge of the ridge.
The doctor should be careful not to push the needle too deep and into the small hole in your skull (the supraorbital foramen) where this nerve passes through.
Before injecting any medication, the doctor will do a test to make sure that the needle is in the right place and not inside a blood vessel.
If all is well, the doctor will then inject a small amount (0.5–1 milliliter) of a medication that numbs nerves (local anesthetic) just under your skin, causing a small, raised area or wheal. More of this medication (1-3 milliliters) will then be injected to ensure the nerve is fully numbed.
Finally, the doctor may place a small roll of gauze (a type of medical bandage) above the ridge of your eyebrow to stop the medication from spreading upwards and causing your upper eyelid to swell.
It’s important to note that because the nerve in this area splits into many branches, the treatment might not work on the first attempt. If this happens, the doctor might need to inject more of the numbing medication above your eyebrow.
Possible Complications of Supraorbital Nerve Block
When a doctor performs a supraorbital nerve block—a procedure to prevent pain or numb a region around your forehead and upper eyelid—there could be some complications, including:
* Hematoma or eyelid swelling: This is when blood collects outside of the blood vessels, causing a swelling or bruise on your eyelid.
* Delayed periorbital ecchymosis: This is a fancy term for a bruise that appears around your eye later after the procedure.
* Infection: Like any procedure that involves the skin, there’s always a risk of infection.
* Bleeding: Sometimes, you might have some bleeding after the procedure.
* Vascular injection of anesthetic: This is when the medicine used to numb the area gets into a blood vessel.
* Nerve injury: This includes conditions like neurapraxia, which is temporary loss of nerve function, or neurolysis, which involves damage to the nerves.
* Local anesthetic systemic toxicity: This happens when too much of the numbing medicine gets into your system and causes harmful effects.
* Allergic reaction to the local anesthetic: Some people might have an allergic reaction to the medicine used to numb the area.
What Else Should I Know About Supraorbital Nerve Block?
When you’re in pain, doctors can provide relief using anesthesia that numbs or blocks the pain. Anesthesia does not only help manage pain, but it also helps doctors perform procedures more effectively while keeping you comfortable. There are different ways to apply this anesthesia; one way is by targeting the tissues or nerves that send pain signals to your brain.
There are two ways of applying anesthesia: local infiltration and nerve block. Local infiltration involves injecting an anesthetic directly into the painful area. This method is great for repairing simple injuries in one specific spot, but it might not be enough if the pain covers a large area or multiple separate locations. Local infiltration can also distort the repair area on the surface of your body, making it less than ideal in some cases.
That’s where a nerve block comes in handy. A nerve block is another way to apply anesthesia, which involves numbing a larger area by directly targeting the nerve. This method uses a smaller amount of anesthetic compared to local infiltration, but it can numb a larger area. This option is beneficial for cases where pain exists over a larger region. As always, the best method varies per individual, so your doctor will determine which option is best for you based on your specific situation.