Get a pronounced effect with a minimum level of discomfort and risks for the patient – 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 injecting cosmetologists avoid nerve damage from fillers.
- Major nerves of the face and types of damage caused by fillers
- Anatomy of the nerves in the forehead
- Anatomy of the nerves in the temporal zone
- Anatomy of the nerves in the cheek region
- Nerve anatomy in the lower third of the face
- How to prevent facial nerve damage due to fillers
Major nerves of the face and types of damage caused by fillers
The main nerves that can be damaged during facial injections, – facial and trigeminal. Trigeminal nerve branches to:
- eye branch;
- maxillary branch;
- mandibular branch.
The trigeminal nerve passes through the foramina of the skull and divides into independent sensory components.
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The facial nerve, on the contrary, has one trunk that passes through the stylomastoid foramen and divides into two branches in the parotid gland:
- cervicofacial;
- temporofacial.
The cervico- and temporo-facial branches, in turn, are divided into:
- temporal;
- zygomatic;
- buccal;
- marginal branch of the lower jaw;
- cervical.
Nerve damage caused by dermal filler injections can be transient, reversible, or permanent.
Injury can occur when drugs are administered by both needle and cannula. In addition to puncturing or partially tearing a nerve with a needle, it can be damaged as a result of:
- filler injections directly into the nerve;
- tissue compression after filler injection;
- too much massage after filler injections.
Nerve damage almost always results in neuropraxia – loss of sensory and/or motor function.
Nerve anatomy in the forehead
Knowing where the nerves are located in the highly sensitive area of the forehead is essential to ensure not only safety but also patient comfort during the procedure.
Anesthetized:
- supraorbital nerve;
- supratrochlear nerve.
Supraorbital nerve – one of the terminal cutaneous branches of the frontal nerve, which in turn departs from the ophthalmic branch of the trigeminal nerve. N. The supraorbitalis provides sensation to the forehead and anterior scalp.
The supratrochlear nerve originates from the supraorbital notch, which can be identified by palpation in the region of the supraorbital margin.
Read also: Forehead anatomy for injectionists: important nuances of the structure and correction of the zone
The location of the deep branch of the supratrochlear nerve appears to be reproducible. A study of 75 patients undergoing an endoscopic brow lift found that, on average, the deep ramus was 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.
In performing the blockade, the author inserts a syringe just below 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 emerges from the ophthalmic branch of the trigeminal nerve. In 30% of cases, the supratrochlear nerve ascends along with the supraorbital. It provides sensitivity to the midline of the forehead.
However, in most cases, the supratrochlear nerve block requires a separate injection lateral to the midline of the face, at the level of the superior orbital ridge.
When working with the lateral borders of the forehead, a zonal injection of local anesthetic may be necessary. For this purpose, the author prefers to use the cannula entry point .
Nerve anatomy in the temporal zone
In the context of injection face correction, it is customary to distinguish several planes. For contouring, the most commonly used technique is introduction of fillers into the space between the temporalis muscle and the bone of the temporal fossa. Injection of the drug into the indicated plane in the superomedial region of the temple minimizes the risk of vascular complications, as well as damage to the zygomatic temporal nerve.
Fig. 1: facial nerves and deep fat compartments
Fillers are also injected:
- between the superficial and deep layers of the deep temporal fascia.
- between deep temporal fascia and temporalis muscle.
For patients with severe volume deficiency in this area, the filler is injected into the space between superficial temporal fascia and deep temporal fascia. Here the doctor works with only a cannula – this reduces the risk of damage:
- superficial temporal artery and vein;
- frontal branch of the facial nerve.
To prevent damage to the neurovascular structures in this plane, the author uses a 22 gauge cannula.
Anatomy of the nerves in the cheek region
The location of the infraorbital foramen in the cheek area is critical to preventing neuropraxia. Damage may result from blockade of the infraorbital nerve. Fortunately, most fillers include lidocaine, which reduces the need for n blockade. infaorbitalis in this zone. However, such anesthesia may be needed for upper lip augmentation. Injection of an anesthetic into the orbit, as well as too much massage after the injection of the filler, can lead to:
- diplopia;
- dysesthesia;
- paresthesia.
Reported cases of Bell's palsy after dermal filler injections. 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
Bell's palsy emergency treatment – short-term course of oral steroids. Surgical decompression and other treatments such as electrography, physiotherapy and acupuncture do not have sufficient evidence base.
Nerve anatomy in the lower third of the face
The marginal mandibular nerve can be damaged during injection correction of the cheeks, jawline and neck. Care must be taken when inserting fillers into the midmandibular border, even by cannula, as nerve damage can lead to impaired mobility.
In most cases, the marginal mandibular nerve passes anteriorly over the border of the mandible, but in 19% of cases – below this limit. Damage in the neck area can occur when the 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 the introduction of dermal fillers into the subplatysmal plane.
Chin augmentation requires blockade of the mental nerve. Care must be taken to avoid nerve damage that can lead to loss of sensation in the front of the chin and lower lip. Dermal fillers should be injected equally carefully into the cupraperiosteal plane.
How to prevent facial nerve damage due to fillers
To prevent nerve damage of the face due to fillers, care must be taken when performing blockade prior to contouring. The correct choice of cannula or needle, depending on the plane of insertion and the presence of neurovascular structures, also plays an important role in the prevention of complications associated with nerve damage.
After injection of the filler, too much massage of the treated area should be avoided to avoid post-injection iatrogenic nerve damage.
Of course, working with preparations based on hyaluronic acid, the doctor has the opportunity to eliminate complications with the help of 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 be extremely careful.
According to Prime magazine.
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