Paralysis of the facial muscles

Bell's symptom is pathognomonic for paralytic lagophthalmos: when the patient tries to close the eyes, the eyelids on the affected side do not close, and through the gaping eye slit it is visible that the eyeball is displaced upward; only the sclera remains visible. This syndrome is physiological, but in healthy people it is not visible due to the complete closure of the eyelids.

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What causes facial muscle paralysis?

The causes of persistent paralysis of the facial muscles may be: neuritis of non-specific and specific origin; damage to the base of the skull due to accidental injuries; inflammatory diseases of the middle ear, damage to the outer ear and jaws; surgical interventions in the area of the cerebellopontine angle, middle and inner ear, in the parotid region (mainly in connection with neoplasms); Bell's palsy and congenital paralysis.

Symptoms of facial muscle paralysis

The symptoms of facial muscle paralysis are varied due to the varying degrees of conductivity disorders of the facial nerve branches. The more branches are involved in the pathological process, the more severe the clinical picture. However, in almost all cases, the main complaints of patients are associated with the presence of facial asymmetry and lacrimation.

In severe cases, they are accompanied by complaints of difficulty in eating food, which gets stuck in the vestibule of the mouth and does not enter the oral cavity without pushing with a finger.

Some patients complain of difficulty pronouncing a number of sounds, especially labial ones, due to the inability to hold air in the mouth and create an air stream of the required pressure.

In some cases, angular cheilitis appears on the affected side. Secondary deformations of the jaws, nose, and auricle are also possible.

Objectively, a more or less pronounced amimia of the affected half of the face is noted. With total damage to all branches of the facial nerve, the corner of the mouth is lowered, the nasolabial fold is smoothed, the cheek is thickened, drooping and pasty, the lower eyelid and eyebrow are lowered, the horizontal folds of the forehead are smoothed (on the affected side), the wing of the nose is slightly displaced downwards, the nostril is flattened, the tip of the nose is displaced to the healthy side.

In cases where paralysis of the facial muscles occurs in childhood, in adulthood, dental and jaw deformations may be observed in the form of unilateral progenia (laterognathia), combined with an open bite. This is explained by the uneven pressure of the cheeks and lips of the paralyzed and healthy halves of the face on the growing and developing jaws. In addition, the chewing process is carried out mainly at the expense of the healthy side, as a result of which more intensive growth of the lower jaw and its lateral shift occur here.

The palpebral fissure on the side of paralysis gapes even at rest, since the lower eyelid is lowered and leaves a wide strip of sclera exposed under the cornea; sometimes the eyelid is sharply everted, and its skin is thinned to the thickness of tissue paper, which is explained by atrophy and dysfunction of the orbicularis oculi muscle and trophic disorders in the lower eyelid area.

The free edge of the upper eyelid sometimes has not the usual arcuate shape, but an arched shape as a result of the traction of the intact muscle that lifts the upper eyelid, innervated by the oculomotor nerve and attached to the middle third of the upper eyelid. For the same reason, the thickness of the upper eyelid does not change.

The eyebrow on the side of paralysis is lowered, which gives the patient a sullen and alienated appearance and limits the upper field of vision.

In case of paralysis of the facial muscles, three variants of Bell's symptom are distinguished:

• the eyeball deviates upward and slightly outward (most common);
• the eyeball deviates upward and significantly outward;
• The eyeball deviates in one of the following ways - upward and inward; only inward; only outward; upward and then oscillates like a pendulum; very slowly outward or inward.

The described varieties of Bell's symptom are important when choosing the method of scleroblepharorrhaphy according to M.E. Yagizarov.

On the healthy side of the face, the tone of the facial muscles is usually somewhat increased. As a result, when smiling, laughing and eating, the face is greatly disfigured due to the increase in the degree of its distortion to the healthy side. This leaves a heavy imprint on the psycho-emotional state of patients, who try to smile and laugh as rarely as possible, and if they do laugh, they bashfully cover their face with their palm or turn their face away so that the interlocutor does not see the sick side of the face.

The severity of the objective local and general status (especially mental) in paralysis of the facial muscles is determined by the duration of the disease, the presence of additional aggravating deformations on the part of the nose, jaws, auricles, as well as atrophic and paralytic phenomena in the masticatory muscles innervated by the motor root of the trigeminal nerve.

Diagnosis of facial muscle paralysis

To assess the severity of facial symmetry disorders in connection with operations in the parotid region, A. A. Timofeev and I. B. Kindras (1996) introduced the concept of the asymmetry coefficient (K) - "the ratio of the magnitude of the displacement of the center of the length of the mouth line to the length of the mouth line in a state of tension when baring teeth."

Electromyography and classical electrodiagnostics methods have established that the majority of patients have a sharply expressed asymmetry of the electrical activity of the neuromuscular apparatus: complete bioelectrical silence on the affected side and hyperelectrical activity on the healthy side. Galvanic excitability of muscles on the affected side is either not determined at all or is reduced to 60-75-90 mV (with a norm of 30-40); chronaxie of the muscles under study on the affected side is also reduced by 2-3 times.

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Treatment of facial muscle paralysis

Surgical methods used to treat facial muscle paralysis can be divided into 3 groups:

• I - operations that statically or kinetically correct facial asymmetry;
• II - operations that, to one degree or another, restore the contractile function of the paralyzed side of the face;
• III - operations on the deformed lower jaw (elimination of unilateral progenia).

The first group of (corrective) operations includes the following.

1. Various methods of static suspension or pulling up to the zygomatic arch of the pubescent and mixed in the opposite direction corner of the mouth (with the fascia of the thigh, bronze wire, thick silk threads impregnated with ferric chloride, multiple silk threads, polyamide thread or lavsan mesh strip, etc.).
2. Kinetic suspension of the drooping tissues of the angle of the mouth to the coronoid process, for example, with lavsan threads.
3. Local plastic surgery in the form of excision of excess stretched and flabby facial skin, narrowing of the widened eye slit, scleroblepharorrhaphy using the Yagizarov method, moving the drooping corner of the mouth upward, etc.
4. Corrective surgeries on the healthy side aimed at weakening the function of healthy facial muscles. This is achieved by cutting the branches of the facial nerve on the healthy side or by turning off the function of individual facial muscles on the healthy side (cutting them with subsequent resection of a section of the muscle belly).

The second group includes the following operations.

1. Muscle plastic surgery on the paralyzed side:
   • cutting out a flap on a leg from the masseter muscle and fixing it to the paralyzed corner of the mouth (according to P. V. Naumov);
   • muscle "neurotization" by suturing flaps from the actual masseter muscle with various paralyzed facial muscles;
   • muscle "neurotization", supplemented by tightening the corner of the mouth with a strip of thigh fascia;
   • myoplasty according to the method of M. V. Mukhin;
   • myoplasty and blepharoplasty according to the method of M. V. Mukhin - B. Ya. Bulatovskaya;
   • one-stage myoexplantodermaplasty according to the method of M. V. Mukhin-Yu. I. Vernadsky.
2. Transplantation of the hypoglossal nerve to the facial muscles.
3. Facial nerve surgeries: decompression, neurolysis (release of the nerve from scars), free nerve transplantation.
4. Suturing the central segment of the facial nerve with the hypoglossal, accessory or phrenic nerve.

The treatment plan for the third group of operations is made based on whether there are any jaw deformations. Although bone plastic surgeries belong to the third group, correction of the lower jaw, if necessary, should be done first. In this case, it is necessary to take into account the nature and degree of bone deformation.

If laterognathia is combined with an open bite, it is necessary to perform a bilateral osteotomy in the form of resection of wedge-shaped fragments of the body of the lower jaw.

In isolated (without open bite) laterogeny, linear osteotomy is indicated at the base of the usually elongated articular process on the healthy side. Osteotomy is combined with resection of a small bone fragment of the jaw branch. 2.5-3 months after the osteoplastic surgery, the deformation of the soft tissues in the area of the corner of the mouth, cheek and eyelids is eliminated. Lastly, operations are performed on the forehead.

Myoexplantodermatoplasty according to M. V. Mukhin - Yu. I. Vernadsky

If the functional capacity of the masticatory muscles is preserved, the following corrective techniques are used: muscle plastic surgery (dynamic suspension according to M. V. Mukhin) in combination with explantoplasty - static suspension to the zygomatic bone (according to Yu. I. Vernadsky) or kinetic suspension to the coronoid process (according to M. E. Yagizarov).

At the same time, excision of excess skin and subcutaneous tissue is performed in the temporal and parotid regions, as well as in the nasolabial fold area (dermatoplasty by Yu. I. Vernadsky or M. E. Yagizarov).

Myoexplantodermatoplasty according to M. V. Mukhin-Yu. I. Vernadsky is a one-stage operation that combines all of the above-mentioned corrective components.

Surgical technique. In the area of the nasolabial fold of the affected side, a linear incision of the skin and subcutaneous tissue 3-4 cm long is made. If the tissues of the affected side of the face are very stretched, two incisions are made, converging at the ends and spaced from each other in the middle by 1-1.5 cm. Between the incisions, the skin and subcutaneous tissue are excised, and the orbicularis oris muscle in the area of its corner is exposed through the wound.

On the paralyzed halves of the upper and lower lips, the skin is punctured horizontally with a scalpel tip in 3-4 places; the intervals between punctures are 1.5 cm. Through these punctures, the lip is stitched horizontally several times with a polyamide thread (d=0.5 mm), the ends of which are held in the wound in the area of the nasolabial fold. After this, one stitch is applied to the puncture wounds with a thin polyamide thread (d=0.15 mm).

In the parotid, temporal regions and behind the auricle, two skin incisions are made, converging at the ends, as in a regular cosmetic operation to smooth out wrinkles or tighten sagging cheeks. The skin between these incisions is excised. The zygomatic arch is exposed and completely resected (according to the M. V. Mukhin method).

A subcutaneous tunnel is created between the wounds of the nasolabial fold and in the area of the zygomatic arch, through which the ends of the polyamide thread used for suturing the lips are passed from the wound at the corner of the mouth to the wound on the temple. The corner of the mouth is pulled up by the ends of these threads and, having tied them in a knot, they are secured on the anterior protrusion-cut of the zygomatic arch, on which a notch is made with a bur so that the thread does not accidentally slip off during further manipulations. In this way, the previously lowered corner of the mouth is brought to its normal level along the pupillary and horizontal lines.

The temporal muscle is exposed and two flaps are cut out from it and separated from the temporal bone (according to the M. V. Mukhin method). The anterior flaps are brought through a subcutaneous tunnel in the lower eyelid to the lower part of the orbicularis oculi muscle to the bridge of the nose, and the posterior-inferior flaps are brought through a skin tunnel (going to the nasolabial fold) to the orbicularis oris muscle. The muscle flaps are respectively sutured with catgut to the fascia of the interbrow space and the orbicularis oris muscle (in the area of its angle). Sutures made of polyamide thread with a diameter of 0.15-0.2 mm are applied to the skin wound in the area of the nasolabial fold, temple, and auricle.

Myoexplantodermatoplasty provides not only a static but also a dynamic (functional-muscular) effect, since the corner of the mouth is not only set in the correct position, but also gets the ability to shift due to the active contraction of the transplanted temporal muscle flap.

The corner of the mouth, pulled up to a normal level with a polyamide thread, provides the displaced muscle flap with the opportunity to take root not in a stretched but in a relaxed state, without the risk of rupture of the catgut sutures, which weaken every day, and displacement of the end of the flap upward and outward.

In addition to the usual bandage, the corner of the mouth and cheek should be fixed with a wide strip of adhesive tape (for 3-4 weeks) in a state of hypercorrection (according to the method of Yu. V. Chuprina).

The patient is prescribed general rest, prohibited from smoking and talking. It is recommended to eat only pureed food.

If the operation is performed correctly and healing occurs by primary intention, the first contractions in the transplanted muscle flaps appear in the period from 4 to 19 days after the operation. The necessary conditions for the operation are careful detachment of the muscle flaps from the squama of the temporal bone, creation of sufficiently free subcutaneous tunnels for them, and fixation of the ends of the flaps in a relaxed state.

Unfortunately, degenerative changes gradually develop in the transplanted muscle flap to varying degrees, as revealed in the experiments of P. V. Naumov et al. (1989) using electron microscopy. Therefore, it is necessary to stimulate blood circulation and contractile function in the flaps as soon as possible after surgery.

To stimulate the contractile ability of the transplanted muscle flaps after the sutures are removed (usually from the 10th day), myogymnastics (voluntary contractions of the flaps) and electrical stimulation, dibazol, and thiamine are prescribed.

By training in front of a mirror, patients learn to balance the contraction of the transplanted flaps and the facial muscles of the healthy side. If necessary, additional intervention should be used - intraoral intersection of the belly of the zygomaticus major muscle and the laughter muscle on the healthy side (to balance the intensity of the displacement of the corners of the mouth when smiling).

According to O. E. Malevich and V. M. Kulagin (1989), supplementing myogymnastics with procedures for electrical stimulation of the transplanted muscle (bipolar transcutaneous method with sinusoidally modulated currents using the Amplipulse-ZT device) allows treatment to begin 5-7 days after surgery and, simultaneously acting on the facial muscles of the healthy side and on the operated side, to achieve a higher functional result of treatment.

Myoexplantodermatoplasty allows to solve three problems at once: static suspension of the drooping corner of the mouth, transplantation of active muscle flaps, removal of excess (stretched) skin and subcutaneous tissue.

The comparative simplicity of the surgical technique allows us to recommend it for performance in any maxillofacial department.

In cases where paralysis extends only to the group of facial muscles that are woven into the corner of the mouth, and the frontal muscles and the orbicularis oculi muscle are not paralyzed, a muscle flap can be cut out not from the temporal muscle, but from the actual masseter muscle using the method of P. V. Naumov, or the coronoid process of the lower jaw branch can be resected (using the Burian method) and a polyamide thread can be fixed to it, which pulls the corner of the mouth outward and upward.

Myoplasty according to M. V. Mukhin - M. E. Yagizarov

It differs from the above in that the soft tissues are suspended not from the zygomatic arch, but from the coronoid process of the lower jaw. The operation begins with cutting out a muscle flap and resecting the zygomatic arch according to M. V. Mukhin. Then a skin flap is excised in the area of the nasolabial fold according to M. E. Yagizarov. A subcutaneous tunnel is created between the two wounds, through which four lavsan threads are passed from front to back and upwards, the lower ends of these threads are fixed to the tissues of the corner of the mouth, and the upper ends are wrapped around the coronoid process. After tying the knots of the threads, a muscle flap is passed from top to bottom and forwards through the subcutaneous tunnel, the end of which is sutured to the orbicularis oris muscle.

When performing myoplasty according to M. V. Mukhin, it is possible, according to the proposal of B. Ya. Bulatovskaya, to split the upper-anterior flap, cut from the anterior part of the temporal muscle, into two parts, one of which is introduced into the subcutaneous tunnel in the upper eyelid, and the second - into the tunnel in the lower eyelid. Both of these parts of the muscle flap are brought to the inner corner of the eye and there they are sutured together. At the same time, allo- or xenocartilage (preserved by deep cooling or fixed in alcohol) is used to weight the upper eyelid, which is introduced in the form of thin plates or in crushed form through a revolver syringe into the soft tissues of the upper eyelid below the conducted muscle flap, closer to the inner corner of the eye. As for the depression of the soft tissues at the site of taking muscle flaps in the temporal region, it is eliminated at the end of the operation by chondro- or osteoplasty.

Isolated Corner of Mouth Suspension

If, along with paralysis of the facial muscles, there is also paralysis of the trigeminal nerve (with atrophy of the masticatory muscles), or if the advanced age and general condition of the patient do not allow the myoplastic component of the operation to be performed, it is possible to limit oneself to static suspension and dermatoplasty according to the method of Yu. I. Vernadsky (see above) or kinetic suspension and dermatoplasty according to M. E. Yagizarov.

Kinetic suspension applied in isolation has the following advantages:

• mobility is achieved in the area of the corner of the mouth)
• the distance between the two points of attachment of the thread (angle of the mouth - coronoid process) does not change, which avoids overloading the suspending thread and its rapid cutting of tissues in the area of the corner of the mouth; c) access to the coronoid process is achieved through one wound.

A tunnel is bluntly made from this wound to the coronoid process and a Deschamps ligature needle is passed from the inside out (through the incisura mandibulae), and then a thick (No. 3) lavsan thread folded in half is looped through. The tissues of the corner of the mouth, both lips, the nasal septum and the chin are suspended from the ends of the thread, which allows for uniform tightening of the displaced parts of the face.

It should be noted that both isolated static and kinetic suspension should be combined with myotomy (myoresection) on the healthy side (usually the zygomatic and muscular muscles). This prevents rapid cutting of plastic threads and achieves closer symmetry of the halves of the face at rest and during a smile.

The advantage of isolated static suspension with polyamide threads according to the method of Yu. I. Vernadsky is that it can be carried out even through a relatively small incision in the nasolabial fold area, which allows for minimal trauma to the patient.

Paralytic (isolated) lagophthalmos is best eliminated not by transplanting a muscle flap from the temporal muscle, but by scleroblepharorrhaphy according to M.E. Yagizarov, by suturing the lower eyelid with the introduction of a plastic implant into it, or by creating a lower eyelid “shell” according to the Grignon, Chowerd, Benoist method, modified by M.E. Yagizarov.

Scleroblepharorrhaphy

Scleroblepharorrhaphy, or fixation of the lower eyelid to the sclera, is based on the use of the features of the Bell phenomenon described above, in particular, the upward movement of the eyeball when closing the eyes. The lower eyelid, fixed to the eyeball, moves with it and therefore tightly closes with the upper eyelid, and when opening the eyes it drops.

Scleroblepharorrhaphy according to M.E. Yagizarov is indicated only for variant I of Bell's phenomenon.

Technique of the operation. In the middle third of the lower eyelid and sclera, symmetrical crescent-shaped wound surfaces are created by excising a semilunar flap of conjunctiva (slightly longer than the diameter of the cornea) in the limbus area under the cornea with exposure of the sclera).

Accordingly, the conjunctiva of the lower eyelid is excised to create a wound surface as close as possible to the edge of the eyelid. Three episcleral catgut sutures (No. 00 or No. 000) are applied. The ends of the sutures passed through the episclera are brought out through the wound surface of the lower eyelid.

The edges of the conjunctival wound defect on the sclera are sutured to the edges of the defect on the lower eyelid. Episcleral sutures on the eyelid skin can be inserted through small incisions on the skin. After the operation, a light pressure binocular bandage is applied.

In the postoperative period, glasses with one transparent section in the center of the glass for the healthy eye are used to immobilize the eyeball, and the operated eye is bandaged for 7-10 days.

Lower eyelid suspension with the introduction of a “shell” (modified by M.E. Yagizarov)

A sickle-shaped plastic implant is inserted into the thickness of the eyelid. This implant is prepared before the operation using a pre-modeled and carefully fitted wax template. The highest part of the implant is its internal pole, which allows for narrowing of the lacrimal lake area.

The implant is suspended with some hypercorrection by thin lavsan threads to the periosteum of the outer edge of the orbit and to the medial commissure of the eyelids. As a result, it is possible, firstly, to raise the lower eyelid uniformly along its entire length, which distinguishes this method from other methods of suspension by threads and strips. Secondly, the implant inserted into the thinned eyelid improves its cosmetic appearance and creates a tight fit to the eyeball.

Correction of eyebrows and brow area according to M.E. Yagizarov

The operation is performed by suturing the subcutaneous tissue in the eyebrow area using a thick lavsan thread (No. 2-3) and pulling it up with separate threads (No. 3-4) to the aponeurosis and periosteum in the scalp area. When passing the thread, the skin areas corresponding to the furrows (wrinkles) of the forehead are captured more superficially. This creates symmetry in the supraorbital area.

If it is necessary to evenly lift the entire eyebrow (and not just its individual sections), it is recommended to first fix a thin, dense plastic explant in the thickness of the eyebrow, curved to the shape of the eyebrow. The implant is pulled to the aponeurosis with separate threads.

Of great practical interest are the experimental and clinical studies by E. G. Krivolutskaya et al. (1991), aimed at restoring individual damaged branches of the facial nerve with its trunk preserved; when removing parotid gland tumors, the authors resected sections of the facial nerve branches that had an intimate connection with the tumor membrane. Using the technique of suturing the distal end of the damaged branch in an "end-to-side" manner to the intact branch of the same nerve, the authors achieved complete success in 70% of patients and partial success in 20%.

Of great interest is the report by Ts. M. Shurgai, A. I. Nerobeev et al. (1991, 1995) on the indications and methods for performing cross-facial transplantation and neurovascularization of muscles (in 15 patients). The authors give preference to the sural nerve as a transplant and believe that cross-facial transplantation of the facial nerve should be performed in all cases of irreversible paralysis, and in cases of the absence of any functional movements after such an operation, free transfer of the neurovascularized muscle should be performed to replace the atrophied facial muscles. We must agree with them that such a method of treating facial paralysis is promising, but requires further improvement.