To obtain a pronounced effect with a minimum level of discomfort and risks for the patient is the goal of any aesthetic procedure. Therefore, knowledge of the anatomy of the vessels and nerves of the face is critically important for a specialist practicing in this industry. Due to the high risk of intra- and extravascular occlusion and its consequences, the topic of the location of vessels, as opposed to nerves, is widely covered in the literature.
This estet-portal.com article contains information from Dr. Munir Somji to help cosmetic injectors avoid nerve damage resulting from filler injections.
- The main nerves of the face and types of their damage during the injection of fillers
- Anatomy of nerves in the forehead
- Anatomy of nerves in the temporal region
- Anatomy of the nerves in the cheek area
- Anatomy of the nerves in the lower third of the face
- How to Prevent Facial Nerve Damage due to the injection of fillers
The main nerves of the face and types of their damage during the injection of fillers
The main nerves that can be damaged during facial injection surgery are the facial and trigeminal nerves. The trigeminal nerve branches into:
- ophthalmic branch;
- maxillary branch;
- mandibular branch.
The trigeminal nerve passes through the openings of the skull and divides into independent sensory components.
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The facial nerve , in contrast, has a single trunk, which passes through the stylomastoid foramen and, at the parotid gland, divides into two branches:
- cervicofacial;
- temporofacial.
The cervical and temporofacial branches are in turn divided into:
- temporal;
- zygomatic;
- buccal;
- marginal branch of the mandible;
- cervical
Nerve damage caused by dermal filler injections can be temporary, reversible, or permanent.
Damage can occur when drugs are administered using either a needle or a cannula. In addition to puncture or partial rupture of the nerve with a needle, it can be damaged as a result of :
- injection of filler directly into the nerve;
- tissue compression after filler injection;
- Too much massage after filler injections.
Nerve damage almost always results in neuropraxia , a loss of sensory and/or motor function.
Anatomy of nerves in the forehead
Knowing where the nerves are located in the highly sensitive area of the forehead is important to ensure not only safety, but also patient comfort during the procedure.
The following are subject to anesthesia:
- supraorbital nerve;
- supratrochlear nerve.
The supraorbital nerve is one of the terminal cutaneous branches of the frontal nerve, which in turn arises from the ophthalmic branch of the trigeminal nerve. N. _ supraorbitalis provides sensitivity to the forehead and front of the scalp.
The supratrochlear nerve originates from the supraorbital notch, which can be identified by palpation in the area of the supraorbital margin.
The location of the deep branch of the supratrochlear nerve appears to be reproducible. A study of 75 patients undergoing endoscopic brow lift found that, on average, the deep branch of n . supratrochlearis is located at a distance of 0.56 mm from a vertical line drawn tangentially to the medial part of the edge of the iris.
When performing a blockade, the author inserts a syringe directly under the eyebrow and injects an anesthetic near the supraorbital notch. The supralateral nerve is also one of the terminal branches of the frontal nerve, which in turn arises from the ophthalmic branch of the trigeminal nerve. In 30% of cases, the supratrochlear nerve rises along with the supraorbital nerve . It provides sensitivity to the midline of the forehead.
However, in most cases, a supratrochlear nerve block requires a separate injection lateral to the midline of the face, at the level of the superior orbital rim.
When working on the lateral borders of the forehead, a zonal injection of local anesthetic may be necessary. For these purposes, the author prefers to use a point cannula entry.
Anatomy of nerves in the temporal region
In the context of injection facial correction, it is customary to distinguish several planes. For contouring, the technique most often used is to inject fillers into the space between the temporalis muscle and the bone of the temporal fossa . Injecting the drug into the specified plane in the superomedial area of the temple minimizes the risk of vascular complications, as well as damage to the zygomaticotemporal nerve.
Rice. 1: facial nerves and deep fat compartments
Fillers are also injected:
- between the superficial and deep layers of the deep temporal fascia.
- between the deep temporalis fascia and the temporalis muscle.
For patients with severe volume deficit in this area, filler is injected into the space between the superficial temporal fascia and the deep temporal fascia . Here the doctor works only with a cannula - this reduces the risk of damage:
- superficial temporal artery and vein;
- frontal branch of the facial nerve.
To prevent damage to neurovascular structures in this plane, The author uses a 22 gauge cannula.
Anatomy of the nerves in the cheek area
The location of the infraorbital foramen in the cheek area is critical to prevent neuropraxia. Damage may occur due to an infraorbital nerve block. Fortunately, most fillers include lidocaine, which reduces the need for n blockade . infaorbitalis in this zone. However, such anesthesia may be necessary for upper lip augmentation. Injecting an anesthetic into the eye socket, as well as too strong massage after injection of filler, can lead to:
- diplopia;
- dysesthesia;
- paresthesia.
There are known cases of Bell's palsy after injections of dermal fillers. In most patients, improvement occurs spontaneously (71%), but in a fairly large percentage of victims, residual weakness of one half of the face persists for life.
You may also be interested in: First aid for central retinal artery occlusion after filler injections
Emergency treatment for Bell's palsy is a short course of oral steroids. Surgical decompression and other treatments such as electrography, physical therapy and acupuncture have no sufficient evidence base.
Anatomy of the nerves in the lower third of the face
The marginal mandibular nerve can be damaged during injection correction of the cheeks, jawline and neck. Caution must be exercised when injecting fillers into the midmandibular border, even with a cannula, as nerve damage may impair mobility.
In most cases, the marginal mandibular nerve passes anteriorly above the border of the mandible, but in 19% of cases it passes below this border. Damage to the neck can occur when filler is injected into the subplatysmal plane, where the cervical branch of the facial nerve is also at risk.
When correcting the neck, it is necessary to avoid introducing dermal fillers into the subplatysmal plane.
Chin augmentation requires a mental nerve block. Care must be taken to avoid nerve damage, which can lead to loss of sensation in the front of the chin and lower lip. Equally carefully, it is necessary to inject dermal fillers into the supraperiosteal plane.
How to Prevent Facial Nerve Damage from Filler Injections
To prevent damage to facial nerves due to filler injections, care must be taken when performing blocks before contouring. The correct choice of cannula or needle, depending on the insertion plane and the presence of neurovascular structures, also plays an important role in the prevention of complications associated with nerve damage.
After filler injection , excessive massage of the treated area should be avoided to avoid post-injection iatrogenic nerve damage.
Of course, when working with drugs based on hyaluronic acid, the doctor has the opportunity to eliminate complications using hyaluronidase injections. But when injecting other fillers, especially permanent ones, the use of hyaluronide. But when working with other fillers, especially permanent ones, in dangerous areas , you must act with extreme caution.
Based on materials from Prime magazine.
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