Introduction:
Plastic surgeons face the substantial and difficult reconstructive issue of facial paralysis due to facial nerve injury. Not only do competent surgical skills and procedures but also a grasp of the causes of facial paralysis and the structure of the facial nerves are necessary for a solution that is both aesthetically beautiful and acceptable. Anyone considering plastic surgery should be informed of the significant danger of nerve injury. While surgical nerve damage is often unavoidable, aesthetic plastic surgery is a bad example because the procedures are elective rather than medically necessary. For a healthy person, it might be heartbreaking to experience worsening after an operation intended to improve a typical structure.
What Exactly Is a Facial Nerve?
The facial nerve serves as a conduit from the brain to a few facial muscles. It manages the facial muscles responsible for expressions like smiling, frowning, and eyebrow lifting. This nerve also processes the majority of the taste sensations on the tongue.
Location:
The facial nerve is the seventh of the 12 cranial nerves in the neural system. There are two facial nerves in the face, one on each side of the skull.
The facial nerve:
- Begins in the brainstem.
- Travels through the skull base near the vestibulocochlear nerve, the eighth cranial nerve that helps one hear and keep balance.
- Opens up in a bone close to the base of the ear and enters the face.
- Opens out near the parotid gland, a significant salivary gland, and branches out from there.
Functions:
The facial nerve controls several facial processes, including stimulating:
- The facial muscle that moves the face.
- The gland that produces tears.
- The little ear muscle in charge of muzzling some noises.
- The tongue's taste organ.
- Sensation in a small area of the ear's skin.
Depending on the severity and location of the facial nerve injury, it may impact several facial features.
What Are the Causes of Nerve Injury?
Any plastic surgery operation has the potential to cause nerve injury. Injury results from stretching, severing, or cauterizing nerves. Nerve injury can range from motor nerve deficits (such as weakening or paralysis of some muscles) to sensory nerve deficits (such as numbness and tingling feeling). Serious nerve injury may have long-lasting repercussions.
What Is Permanent Facial Paralysis?
Rarely, severe injury to the facial nerve branch causes permanent facial paralysis. The facial nerve comprises the frontal, zygomatic, buccal, marginal mandibular, and platysmal branches. The frontal nerve branch is most frequently linked to long-term facial paralysis. However, severe damage to any facial nerve branch can result in permanent facial paralysis.
The loss of facial mobility is a symptom of permanent facial paralysis. Facial muscles frequently weaken or droop as a result. Additionally, one or both sides of the face could be permanently paralyzed. Symptoms of facial paralysis might appear at different times.
What Are the Symptoms of Permanent Facial Paralysis?
The following are typical signs of permanent facial paralysis:
- Having trouble moving one or both sides of the face.
- Decreased tearing.
- Facial weakness or drooping.
- Unsteady speech.
- Modification of taste.
- Drooling.
- Pain in the ear or behind it.
- Trouble eating or drinking.
What Are the Nerves Injured in Various Facial Surgeries and Their Clinical Manifestation?
- Endoscopic, trichophytic, petechial, or coronal brow lifts performed in the brow and forehead region may damage the frontotemporal division of the facial nerve, resulting in ipsilateral forehead paresis or paralysis, with brow ptosis.
- Midfacial malar or submalar augmentation and subperiosteal midface lift performed in mid-face may damage zygomatic and buccal branches of the facial nerve, resulting in complete lack of eye closure, the collapse of the external nasal valve (a nasal blockage), drooping of the corner of the mouth, an asymmetrical smile, and food spillage
- In facelifting procedures, all facial nerve branches may get damaged and can cause paralysis of any part of the face.
- In chin implant procedures, the marginal branch of the facial nerve may get damaged, resulting in an asymmetric smile.
How to Avoid Facial Nerve Injury During a Facelift?
A thorough understanding of the facial anatomical structures and the facial nerve's anatomy is crucial. However, because the anatomy of high-risk areas is so diverse and varies from patient to patient, surgeons should always dissect accurately to understand facial anatomy. As crucial as the dissection itself is paying close attention to small details.
- Caution should be exercised when injecting solutions with tiny cannulas or fine needles. It is advisable to avoid intra-op anesthetic solutions.
- It is advised to use hydro dissection because it helps the undermining of tissue and avoids needless sharp dissections that increase the danger of unintentional injuries and hematoma formation.
- Techniques for hemostasis and suturing are also crucial. Sutures should not be placed deeply and should instead be placed along the primary facial nerve branches' axis. A surgeon must also avoid unnecessary stretching and excessive traction. To reduce the stress caused by electrocoagulation, it is recommended to utilize a bipolar cautery rather than big clamps or forceps during hemostasis.
- A neurostimulator must be immediately available in the operating room to confirm any suspicion if there is any doubt about a nerve branch injury.
What to Do When a Nerve Section Is Shown During an Operation?
- On rare occasions, the surgeon will be able to locate the facial nerve branch that is injured. The nerves get thinner as the dissection moves closer to the nasolabial fold, making it challenging to correctly identify the anatomy with the naked eye.
- Numerous studies have been published that describe surface anatomy landmarks that correspond to the nerve divisions; nevertheless, the logical next step is to use a neurostimulator to test the presumed injured branch and the nearby ones to avoid misidentification.
- The nerve is sutured after this procedure. Under magnification, the nerve's proximal and distal ends are dissected. A non-absorbable 10 or 9.0 nylon suture is used to perform an epineural suture after checking for substance loss.
What Should Be Done About Postoperative Paralysis?
The majority of the time, the surgeon will experience postoperative paralysis. When practicable, assessing the facial mimetic muscles after surgery can help distinguish surgical stress from other postoperative reasons like Bell's palsy. Maintaining a thorough follow-up and documenting every interaction with the patient using photos is crucial.
Facial nerve palsy can be classified as complete (inability to contract facial muscles freely) or incomplete (partial). Nerve conduction investigations (electromyography-EMG) of the facial nerve can also be used to determine the severity of the nerve injury. Axonal degeneration is suggested by a reduction in the compound muscle action potential, whereas an increase in latency indicates demyelination of the nerve.
How to Manage Facial Paralysis Caused by Facial Nerve Injury?
- Eye Safety: If the lid commissure is left open, one of the main issues with upper-face facial palsy is the involvement of the eye. In this case, eye care focuses on preventing the cornea from drying out, dehydrating, or abrading due to insufficient lid closure or tears. It is advised to wear protective glasses during the day and eye ointments at night.
- Physical Therapy: This helps to reestablish facial coordination, strengthen muscles, and have symmetrical facial features.
- Corticosteroids: These drugs can help the facial nerve feel better by reducing swelling and irritation.
- Speech Therapy: This might assist one in regaining the ability to speak and swallow.
- Occupational Therapy: This can aid in improving tasks such as facial expressions and interpersonal interactions.
- Botulinum Toxin: Botulinum toxin treats synkinesis, hyper lacrimation, and hyperkinesis. It has been reported to decrease face asymmetry in people with facial paralysis when injected into facial muscles.
Conclusion:
Facelift surgery puts several motor and sensory nerves at risk. To prevent neurologic injury, which may be very incapacitating for patients, it is imperative to have a complete understanding of nerve structure. Depending on how severely the nerves have been disrupted, therapy for an injury might range from simple monitoring to investigation and grafting. During facial cosmetic surgery, careful dissection technique, guided by an understanding of facial anatomy, should minimize the risk of neurologic complications.
