Facial paralysis reconstruction
Last updated date: 12-May-2023
Originally Written in English
Facial Paralysis Reconstruction
Infectious, neurologic, congenital, neoplastic, traumatic, systemic, and iatrogenic factors all have the potential to induce facial paralysis. The treatment of facial paralysis, regardless of the cause, is complicated and frequently necessitates multidisciplinary intervention. Because of the vast heterogeneity in the ability for regeneration and the lack of good prognostic indicators for spontaneous recovery, evaluating and treating facial paralysis is challenging. Currently, pharmaceutical treatment, physical therapy for face neuromuscular retraining, and surgical intervention using dynamic and static approaches for facial reanimation are used to treat facial paralysis.
What is Facial Paralysis?
A disorder in which the face is partially or completely paralyzed is known as facial paralysis. Bell's palsy is a frequent cause of facial paralysis that involves abrupt weakness and drooping on one side of the face. Bell's palsy is normally only transitory, but rare forms of facial paralysis can linger for months or even years, impairing your ability to smile, bite, or close your eyes. Other patients can move again, but not in a coordinated fashion. Synkinesis is the medical term for this condition.
Performing electromyography (EMG) or nerve conduction test is the initial step in treating facial paralysis. This test is commonly used to determine whether you have nerve damage and, if so, how severe it is. This is key in detecting and treating face paralysis, particularly Bell's palsy because abrupt weakness is frequently caused by facial nerve inflammation.
Depending on the patient's situation, dynamic and/or static techniques can be used to alleviate facial paralysis. Static operations maintain the tissues of the face or may passively assist a section of the face in moving, whereas dynamic procedures help restore active movement to the face. Static operations are typically simple, outpatient procedures, whereas dynamic procedures usually need a few nights in the hospital.
What Causes Facial Paralysis?
Facial nerve paralysis can be caused by a variety of factors. These are some of them:
- Tumors that damage the nerve or arise in the salivary glands nearby. In some cases, resection of malignancies necessitates the deliberate sacrifice of a nerve.
- Bell's palsy. This is the most prevalent and unknown cause of sudden facial nerve paralysis. Over a few months, some people recover partially, but some people still have facial weaknesses.
- An injury caused by a traumatic event. Crush injuries or nerve transections can occur as a result of accidents or interpersonal aggression.
Facial Paralysis Manifestations
The extent and severity of facial paralysis are determined by the branches or trunks that are affected.
- The temporal branch is responsible for elevating the eyebrow by innervating the frontal muscle. Brow drooping is caused by facial paralysis affecting the temporal branch.
- Blinking, forceful eye closure, and lower eyelid support are all controlled by the zygomatic branch, which animates a part of the eye muscle. Loss of zygomatic branch function causes drooping or outward rotation of the lower eyelid, as well as difficulties or partial eye closure. The zygomatic branch also feeds the muscles responsible for smiling and lifting the mouth corner, and its paralysis causes the latter to droop. Involuntary drooling and speech problems may arise as a result of this.
- The buccal branch is vital for chewing, whistling, and smiling because it provides part of the cheek muscles that maintain the cheek skin tautly.
- The marginal mandibular nerve relaxes part of the lip depressor muscles, resulting in an abnormally elevated lower lip and asymmetrical smile when they are paralyzed.
- The cervical nerve branch maintains muscular tone by supplying certain neck muscles.
Reconstruction Facial Paralysis
For facial reanimation in patients with facial nerve paralysis, both dynamic and static reconstruction techniques are used. Unless there are health risk contraindications, dynamic techniques should be presented to every patient considering reconstruction as they tend to be more effective and fruitful.
The most popular methods for repair include muscle transfer, nerve transfer, cross-facial nerve grafting, and direct facial nerve repair with or without grafting (either regional muscle or free-muscle transfer).
Any form of intervention in the evaluation of patients with facial paralysis must be preceded by a thorough history and physical examination. The onset and duration of paralysis, general health information and overall medical status, and any past surgical treatments are all important parts of the history. The patient's overall health and life expectancy must be considered; for example, a procedure that takes two years to provide results is inappropriate for a patient with a terminal condition. Realistic expectations must be established soon in the patient's education, and the patient must be motivated to invest the time and financial resources required for a good outcome.
The most essential determinant in selecting the timing and type of reconstructive approach is the etiology, therefore intervention should wait until the reason for paralysis has been determined. Idiopathic, traumatic, infectious, neoplastic, neurologic, or systemic/metabolic causes of facial nerve paralysis exist.
The onset's history can provide important etiological clues. An abrupt onset, for example, could indicate Bell palsy, which can heal on its own. An irreversible method to reanimate the face of such a patient is not the best option. Insidious onset, on the other hand, could indicate undiscovered cancer that necessitates additional investigation. After the cause has been determined, the potential for recovery can be assessed, and reconstruction planning can begin.
The length of paralysis is also a significant factor in preoperative planning. The availability of proximal and distal nerve endings, as well as viable facial musculature, determines the approach to reanimation. After denervation, the facial musculature fibrosis, and may not be suitable for reinnervation in a patient with long-term paralysis.
At rest, the physical examination should determine if the paralysis is total or partial, unilateral or bilateral, symmetric or asymmetric. Brow ptosis, dermatochalasis, skin elasticity, oral commissure incompetence, and ocular exposure should all be considered when assessing facial asymmetry. The degree of synkinesis, if present, the presence of additional cranial nerve impairments, and the condition of the eye are all important concerns. With the rest of the face at rest, discrete region-specific facial movements such as brow elevation, eye closure, smile, pucker, and frown should be observed and recorded.
Still photographs, video recordings, and digital photography can all be used to capture objective measures of facial movements. The House-Brackman face grading method is commonly used, although there is no standardized and globally approved system for evaluating facial movement and facial nerve dysfunction.
Audiometric testing, such as tympanometry and acoustic reflex determination, may help determine the origin of facial paralysis caused by retro-cochlear disease or middle ear mass lesions. In the assessment of patients with a suspected tumor of the parotid gland, internal auditory canal, cerebellopontine angle, or skull base, as well as a patient with idiopathic or traumatic facial paralysis, radiologic studies with high-resolution computed tomography and magnetic resonance imaging should be considered. Nerve excitability testing (NET), electroneuronography (ENoG), and electromyography (EMG) are electrodiagnostic studies that can provide extra details about the facial nerve and the integrity of the muscles that it innervates.
Early Facial Paralysis Reconstruction
Early reconstructions following facial nerve damage can generally preserve the original facial expressive muscles. If the facial nerve is missing, other nerves may be used to supply the muscles.
Direct Nerve Repair
If the facial nerve is cut, it may be possible to heal it immediately, especially if it is treated within a few days of the injury. A nerve graft or a piece of another nerve, generally the sural nerve from the calf, is sometimes required to fill the gap between the two cut ends in these injuries.
Cross-Facial Nerve Graft
The normal, undamaged facial nerve on the other side of the face may be a source of nerve fibers in cases of facial paralysis involving only one side of the face. A nerve graft can be used to connect extra facial nerve branches from the functional side of the face to the paralyzed side of the face. The nerve fibers then sprout from the functional facial nerve to the defective nerve and paralyzed muscles, passing through the nerve graft. The nerve graft works similarly to an extension cord, but it takes months for the nerve fibers to grow across the face and reach their destination.
The sural nerve of the calf is commonly used as a nerve graft. The sural nerve is a sensory nerve that can be used up. Two or three small incisions are used to remove it from the leg. After the sural nerve is severed from the leg, a numb patch on the outer side of the foot persists. Walking does not necessitate the use of this nerve.
There is no healthy facial nerve to borrow from in situations of paralysis involving both sides of the face. Other adjacent nerves can be used to supply the facial muscles with a nerve feed. The masseteric nerve, a branch of a nerve used in chewing, is often used. This nerve branch isn't necessary, and its absence doesn't cause chewing problems. The damaged facial nerve might be attached to the masseteric nerve branch. This nerve transfer does not necessitate the use of a nerve graft; hence no leg surgery is required. Following surgery, the patient will require therapy to relearn how to move his or her face using this nerve.
Dynamic Facial Paralysis Reconstruction
Dynamic Reconstruction The following are some examples:
Regional Muscle Transfer
Muscles related to chewing that are innervated by the trigeminal nerve (cranial nerve V) can sometimes be partially manipulated to allow facial movement on the paralyzed side of the face.
Free Functional Muscle Transfer
Free functional muscle transfers have become more reliable and beautiful thanks to advancements in microsurgical procedures. To produce movement, a portion of a muscle from another part of the body can be moved to the face. The gracillis muscle, which originates in the inner thigh, is an expendable muscle that is well-suited for transplantation to the face. The excision of this muscle from the thigh does not affect leg mobility since four other muscles fulfill the same function. The muscle segment is moved together with its blood vessels (which keep it alive) and nerves (so that it may move). The blood vessels and nerves in the face are then connected to blood vessels and a nerve. The muscle is positioned in such a way that when it contracts, it causes the corner of the mouth and upper lip to smile.
This method is technically challenging because it necessitates the use of microsurgery to join vessels using sutures (stitches) that are hundreds of times thinner than human hairs. Depending on the nerve feed that will be replaced, this repair may be done in one or two surgical stages. This technique is most typically used in conjunction with a cross-facial nerve graft and the opposite face's facial nerve (two stages) with CFNG/VII or a masseteric nerve transfer (one stage). The donor nerve (either the graft or the masseteric nerve) is attached to the gracillis muscle nerve (the obturator nerve) in each of these cases. The nerve fibers in the transferred gracillis muscle gradually grow into it, allowing it to contract over time, usually for 4-9 months or more. A gracillis muscle can be transplanted to each side of the face for bilateral repair. Doctors like to do this in two procedures, spaced at least three months apart.
A nerve graft is a piece of nerve, generally a small sensory nerve, that is utilized to fill the gap between two motor nerves. Because nerves are occasionally removed along with tumors, this surgery can be beneficial after the tumor has been removed. Nerve grafting can help fill the gap and restore function to the nerve. Cross-face nerve grafting is a treatment that involves connecting nerves from the non-paralyzed side of the face to muscles on the paralyzed side of the face.
A nerve transfer is a technique in which a cosmetic surgeon disconnects a motor nerve from a less significant muscle and links it to a non-functioning muscle.
After a nerve has been injured, this treatment is frequently used to help reanimate paralyzed facial muscles. Learning to control the muscles with the new neural connection requires some practice. A treatment known as the babysitter procedure uses nerve transfer to minimize muscle atrophy during multi-stage reconstructions.
Static Facial Paralysis Reconstruction
Static facial reanimation techniques have several advantages that might complement or replace the outcomes of dynamic facial reanimation. Static approaches can be used to treat chronic facial paralysis as well as transient facial paralysis with the hope of nerve recovery. For the upper and lower zones of the face, static procedures for facial reanimation will be discussed.
Brow Ptosis Correction
Correction of brow ptosis is an important element of the treatment of patients with facial paralysis. Direct brow lift (coronal, mid-forehead, or brow cut), endoscopic brow lift, or minimally invasive temporal brow lift with a biodegradable stabilizing device have all been documented.
Management of the eye
Exposure keratitis can result in irreversible vision loss, hence oculoplastic care for the paralyzed eye is critical. The following techniques can be used to treat the upper eyelid as needed:
- Placement of an eyelid weight. lid loading with a gold or platinum weight is a very effective approach for lagophthalmos correction. When compared to gold implants, thin profile platinum weights are becoming increasingly common since they provide superior cosmetic results and a lower incidence of allergies.
- Palpebral spring procedure. The palpebral spring procedure is a technically complex procedure that can be used to correct lagophthalmos instead of using an eyelid weight. The spring connects the periosteum of the superior orbital rim to a pocket on the superior aspect.
- Upper eyelid blepharoplasty. to eliminate extra skin in patients with substantial dermatochalasis, a conservative upper lid blepharoplasty might be done.
- Lateral tarsorrhaphy. Mattress sutures can be used to coapt the lateral sides of the upper and lower lid tarsal plates for a permanent reversible lateral tarsorrhaphy. In addition to lagophthalmos, tarsorrhaphies are commonly employed in cases of exposure keratitis or when there is a loss of corneal sensation.
As needed, the lower eyelid is treated with the following procedures:
- Lateral tarsal strip procedure. An effective approach for treating paralytic lower lid ectropion is the lateral tarsal strip procedure. A lateral canthotomy is done first, followed by inferior crus cantholysis in this procedure. The lower tarsus is resected and stitched back directly to the periosteum of the lateral orbital rim.
- Medial canthopexy. A precaruncular medial canthopexy procedure is used to treat medial paralytic ectropion of the lower eyelid, in which the medial tarsus is stitched to the periosteum of the lamina papyracea.
Nasolabial Fold Modification
A simple suture approach can be used to form or efface the nasolabial fold crease in patients with effacement of the nasolabial fold or over-prominent nasolabial folds.
Static Facial Suspension
Static facial slings are commonly put from the zygomatic arch/temporalis fascia to the oral commissure and nasolabial fold for facial stability. Fascia lata, Gore-Tex, and AlloDerm are some of the materials that have been considered for usage as sling materials. Multi-vector suture approaches for face suspension have also been described.
External Nasal Valve Repair
External nasal valve collapse is a common complication in patients with facial paralysis. To stent open the external nasal valve, a fascia lata sling from the alar base to the zygoma/temporalis fascia can be used.
For the treatment of patients with facial paralysis, the reconstructive surgeon has a wide range of surgical therapeutic choices. When screening patients with facial paralysis, an organized, thorough approach is required to ensure that no obvious therapeutic options are neglected. The major surgical treatments for acute facial paralysis are facial nerve decompression and facial nerve repair. Nerve transfer methods are appropriate for facial paralysis of intermediate duration. Treatment for persistent facial paralysis usually entails regional or free muscle transfer. It's vital to remember that static facial reanimation procedures can be employed for acute, intermediate, or chronic facial paralysis and that these treatments are frequently useful complements to the overall management strategy.