Anterior dislocation of the lower jaw: causes, symptoms, diagnosis, treatment

Depending on the direction of displacement of the head of the lower jaw, the dislocations are divided into the front (the head is shifted forward) and the rear (the head is shifted backward), one- and two-sided. Most often, anterior dislocation of the lower jaw occurs. The displacement of the head inward or outward is very rare, only when the joint is dislocated with the fracture of the condylar process (fracture-dislocation).

Dislocations of the lower jaw range from 1.5 to 5.7% of all dislocations; occur more often in women aged 20 to 40 years, since the ligamentous apparatus of their joints is not strong enough, and the mandibular fossa of the temporal bone has a small depth.

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What causes anterior dislocation of the lower jaw?

Depending on the frequency of occurrence, the dislocations are divided into acute and habitual.

Occurrence of casual (acute) anterior dislocations is facilitated by:

1. relaxation of the ligament-capsular apparatus;
2. Deformation (hypertrophy) of the articular elements;
3. change the shape, size and structure of the interarticular disk.

The habitual dislocation of the lower jaw is due to some deformation of the jaws, anomaly of the closing of the teeth (for example, prognosis with loss of molars).

Dislocation of the mandible anteriorly usually occurs as a result of excessive opening of the mouth with yawning, screaming, vomiting, removing teeth, biting off a large chunk of food, sometimes it is observed with gastric intubation, tracheal intubation, and anesthesia with tracheobronchoscopy.

Traumatic dislocation of the lower jaw usually occurs as a result of a blow to the area of the lower jaw: when the sagittal direction of the impact occurs, the bilateral chin appears in the lowered chin, and when it strikes from the side, it is a one-sided dislocation on the side of the impact.

Symptoms of anterior dislocation of the lower jaw

The anterior dislocation of the lower jaw is characterized by the displacement of the head of the lower jaw forward with respect to the joint lump of the temporal bone, as a result of which the mouth is open (especially widely - with bilateral dislocation), the chin is shifted downward and forward (with bilateral dislocation), the patient experiences more or less severe pain . Speech is difficult, chewing is impossible, mouth is flowing from the mouth, as it is difficult to close the lips, and sometimes it is impossible. With a unilateral dislocation of the lower jaw, the chin with the central incisors and the bridle of the lower lip moves to a healthy side; the mouth is half open, the lips can be closed. The movements of the lower jaw are possible only downwards, with the mouth opening more. Ahead of the tragus of the ear is determined by the westernization, and under the malar pulp in front of the articular tubercle of the temporal bone - protrusion due to the displacement of the head of the lower jaw into the dorsal fossa. The posterior edge of the jaw branch acquires an oblique direction, the angle of the jaw is close to the mastoid process of the temporal bone.

The X-ray of the temporomandibular joint in the lateral projection shows that the dislocated head of the lower jaw is in front of the joint lump of the temporal bone.

Outcomes and complications of anterior dislocation of the lower jaw

If the direction and subsequent immobilization of the jaw are made in a timely manner (within the next few hours after the dislocation), complications are not observed. Only in some cases, a long time, there is a pain when chewing, which is eliminated by physiotherapy. When untimely reposition treatment dislocation mandible is more difficult.

Outcomes and complications of a chronic anterior dislocation of the lower jaw

Outcomes of chronic dislocation of the mandible are usually favorable. If there is insufficient application after surgery, mechanotherapy may develop contracture of the lower jaw.

Differential diagnosis of anterior dislocation of the lower jaw

One-sided anterior dislocation of the lower jaw must be differentiated with a one-sided fracture of the lower jaw, in which there is no symptom of extending the chin forward and to the healthy side.

Two-sided anterior dislocation of the mandible should be distinguished from a bilateral fracture of the condylar processes or the jaw branch with a displacement of the fragments. Thus it is recommended to consider the following seven signs:

1. In both cases, the bite is open, but with the dislocation the chin and the entire frontal group of teeth are pushed forward, and with a fracture are displaced posteriorly. When dislocation, the appearance of the patient lila is progenic, and in case of fracture, prognathic.
2. In a patient with a fracture, the amplitude of jaw movements is greater, and the restriction of opening the mouth is caused by painful sensations. With a dislocation, only some additional opening of the mouth is possible , although the patient does not experience significant pain when trying to move the lower jaw .
3. With a fracture, the posterior edges of the mandibular branch are more vertically and distally than when they are dislocated.
4. When palpation of the upper part of the posterior edge of the jaw branch, one can detect its deformation and localized pain (in the place of fracture of the bone), which is not present in patients with dislocation.
5. With a fracture and dislocation of the lower jaw, there is no sensation of mobility of the lower jaw heads when they are palpated through the external auditory canals; However, with a fracture (without the dislocation of the joint head), there is no westing in front of the tragus.
6. Radiographically, with a fracture not accompanied by a dislocation, the head of the lower jaw is in its usual place, and when it is dislocated, it leaves the articular fossa and lies in front of the articular tubercle.
7. In the case of a fracture of the lower jaw, unlike the dislocation of the lower jaw, the shadow of the fracture is visible on the roentgenogram .

The prognosis of acute dislocation is favorable, since it is easy to diagnose and eliminate it in most patients.

Complications of acute dislocation of the lower jaw are most often relapses and habitual dislocations.

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Elimination of anterior dislocation of the lower jaw

The Method of Hippocrates

The patient is seated on a low chair or stool with his back to the back of the chair or to the wall (for the occipital region of the head to have a strong support). In this case, the lower jaw of the patient should be slightly higher (up to 10 cm) of the level of the lowered upper limbs of the doctor standing in front of the patient. Compliance with this condition allows the doctor to achieve complete relaxation of the chewing muscles of the patient with minimal effort.

Standing face to the patient, the doctor wraps the thumbs of both hands with gauze napkins or the ends of the towel and sets them on the right and left on the chewing surfaces of the molars (in the absence of them - on the alveolar sprouts); With the other four fingers, he grasps the dislocated jaw from below. Gradually and gently pressing the thumbs down, and the rest - up (on the chin), the doctor achieves fatigue and relaxation of the chewing muscles and forcibly pushes the lower jaw down - somewhat below the level of the joint joints. After this, smoothly shifts the jaw back, so that the joints are plunged into the articular fossa. The return of the heads to their normal position is accompanied by a characteristic click sound (due to their rapid slipping from the tubercles into the joint fossa) and reflex compression of the jaws.

Therefore, by shifting the jaw to the back, the doctor must simultaneously quickly move the thumbs of both hands towards the cheeks (into the vestibular space) to avoid biting them. With a bilateral dislocation, both heads are fixed simultaneously or first with one, and then with the other.

Method Hippocrates - P. V. Khodorovich

In view of the fact that the thumbs wrapped with a napkin become bulky and touch is dulled, PV Khodorovich suggested inserting the thumbs on the threshold of the mouth and imposing them not on the large molars but on the external oblique lines of the lower jaw at the level of the large molars so so that the nail phalanx occupies the retromolar fossae (triangles) and with their ends rest against the front edges of the branches of the jaw. The index fingers cover the corners, and the rest - the body of the jaw. When the lower jaws are inserted into the joint fossa, the thumbs of the doctor in this case can not be trapped between the teeth of the patient, because they remain in the retromolar fossils until the end of the manipulation.

If in the process of eliminating a bilateral dislocation only one articular head of the lower jaw sets in and the position of the other remains incorrect (dislocated), the physician should continue to correct it as in a unilateral dislocation.

It should be taken into account that the more physically developed the patient is, or the more he is excited, the longer the fatigue of the masticatory muscles does not occur, and the more time it takes to correct the lower jaw.

At the expressed painful sensations in the stretched joint capsules, the ligamentous apparatus and masticatory muscles to fix the lower jaw it is rather difficult. In such cases, a regional anesthesia for Berchet-M should be carried out in advance. D. Dubov, and if this can not be done, the jaws should be slowly pushed back, distracting the patient's attention.

After eliminating the dislocation, it is necessary to immobilize the lower jaw for 10-15 days using a bandage bandage bandage or a standard plastic sling with an elastic stretch to the head cap. In the period of such immobilization, the patient should take shredded food.

The method of GL Blekhman-Yu. D. Gershuni

The essence of GL Blechman's method is that the doctor presses the coronoid processes of the lower jaw in the direction of the back and down with the index fingers on the protruding (at the dislocation) on the threshold of the mouth . The resulting painful sensation leads to reflex relaxation of the masticatory muscles; the jaw is fixed for a few seconds.

Yu. D. Gershuni modified the method of GL Blekhman in the following way. Palpation through the cheek skin, somewhat below the zygomatic bones, determine the position of the apexes of the coronary processes of the lower jaw and press them with the thumbs in the direction of the back and down. This eliminates the need for a large physical force, eliminates the need for an assistant, the correction can be carried out at any position of the patient and under any conditions. This method can quickly train not only health workers, but also relatives of patients. An important point is that the correction is carried out without inserting the fingers into the mouth of the patient. It is especially advisable to use this method in elderly and senile people.

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Elimination of the chronic anterior dislocation of the lower jaw

Eliminate the chronic anterior dislocation of the lower jaw in the same way as the fresh one, it is often very difficult or impossible. Irregularities can also be dislocations of the lower jaw, repeatedly recurring after long periods of time. In such cases, you should try to fix the lower jaw by the Popesku method, which is as follows. The patient is placed on his back, the mouth is opened as wide as possible and between the molars are interposed tightly bandage rollers with a diameter of 1.5-2 cm; continuously pressing his hand on the chin from the bottom up, lower the head of the lower jaw. Then press down on the chin from front to back.

After repositioning the heads, immobilize a circular bandage of bandage or sling for 2-3 weeks, and then prescribe a metered and gradual mechanotherapy.

In patients with chronic dislocation, the jaw is usually placed under anesthesia or under potentiated local anesthesia (according to Berchet-M. D. Dubov). When eliminating the difficult correct long-term dislocations, short-acting muscle relaxants (canine, dithilin) are used intravenously in combination with anesthesia. If such an attempt was unsuccessful, they usually produce an operative route, exposing the edge of the incision of the lower jaw with a 2-2.5 cm long cut along the lower edge of the zygomatic arch. Having grasped the branch of the jaw with a strong crochet for a half-moon cut, pull it down, and then, pressing on the chin, move the head of the jaw back and this is established in the mandibular fossa. If the reposition is impeded by a deformed articular disc, it is removed. After restoring the head of the jaw, the wound is sewn layer by layer.

If this correction can not be made due to gross cicatricial changes around the joint and in the joint cavity itself, the mandible is resected and immediately after wound healing, active and passive mechanotherapy is prescribed, using standard devices for this purpose.

To correct the hard and chronic dislocations of the lower jaw, a method based on the possibility of using a device used in the treatment of fractures of the condylar processes of the mandible is proposed, since this device makes it possible to lower the dislocated head of the jaw branch. It is described above. To correct the dislocation of the lower jaw, one of the fixing hooks is inserted under the zygomatic arch, and the other hook-arm rest on the edge of the incision of the lower jaw. After that the regulating screw reduces the branch of the jaw, which leads to a separation of the contact of the posterior surface of the articular head with the anterior surface of the articular tubercle and the location of the upper point of the articular head below the lower point of the articular tubercle. The correction ends with the inclination of the carrier rod of the device, leading to the movement of the head towards the mandibular fossa, followed by the raising of the branch and the introduction of the head into the pit. The device allows a gradual, with a metered force, to lower the branch of the jaw, which prevents the rupture and damage of articular ligaments.

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