Fracture of the lower jaw: causes, symptoms, diagnosis, treatment

In peacetime, the incidence of facial injuries is 0.3 cases per 1000 people, and the proportion of maxillofacial trauma among all injuries with bone damage in the urban population ranges from 3.2 to 8%. At the same time, facial bone fractures are observed in 88.2%, soft tissue injuries - in 9.9%, and facial burns - in 1.9% of cases.

The number of patients with facial injuries in peacetime ranges from 11 to 25% of all those hospitalized in the maxillofacial clinic, with facial bone injuries accounting for approximately 15.2% of all body bone fractures.

The most common are isolated fractures of the lower jaw (79.7%), followed by fractures of the upper jaw (9.2%), followed by fractures of the nasal bones (4.6%), then fractures of the zygomatic bones and zygomatic arches (4.1%), and only 2.4% of cases are fractures of both jaws observed. Among patients with jaw fractures, 83.7% were individuals with isolated injuries to the lower jaw, 8% - to the upper jaw, and 8.3% of victims had injuries to both jaws.

What causes a jaw fracture?

In peacetime, jaw fractures are most often caused by blows and bruises from falls, compression (industrial injuries), fights, etc. Jaw fractures often occur in road traffic accidents. In rural areas, jaw fractures can occur as a result of a blow from a horse's hoof, the handle of an "old" tractor, etc.

Gunshot fractures of the jaws are relatively rare and are usually the result of improper handling of weapons (usually hunting weapons), children's pranks, etc. In recent years, intentional gunshot wounds to the face by criminals have become more frequent.

Among the causes of damage to the upper jaw, domestic trauma also predominates, although to a somewhat lesser extent.

Sometimes there are “medical” injuries to the upper jaw in the form of perforation of the bottom of the maxillary sinuses, which occur during the process of tooth extraction (usually large or small molars).

Combined injuries of the upper and lower jaws and other areas of the body account for 14% of the total number of combined mechanical injuries. Most often, they are caused by road accidents (52%), falls from height (25%), and household injuries (17%). Industrial injuries account for only 4%, accidental gunshot wounds - 1.3%, and other causes - 0.7% of cases.

The prevalence of maxillofacial injuries in men compared to women (8:1, 9:1) is explained by their greater employment in industrial and agricultural production, transport, as well as alcohol abuse (13.6-27.3% of cases).

Damage to the facial bones is most often observed in the summer-autumn months, coinciding with the period of vacations and tourism, and less often in the winter.

Symptoms of a Mandible Fracture

Symptoms of a mandibular fracture depend on the degree of displacement of the fragments, the number of jaw fractures, the presence or absence of a concussion or brain contusion, damage to the soft tissues of the face and oral cavity, the presence of damage to other bones of the face, the base of the skull, etc.

It should be noted that severe biochemical disturbances occur in the blood of victims immediately after the injury; the content of ATP, aluminum, titanium, transferrin, ceruloplasmin activity, alkaline phosphatase, and total lactate dehydrogenase increase proportionally to the severity of the fracture and, consequently, the general condition of the patient (V. P. Korobov et al., 1989). All these and other circumstances (age, background diseases) explain the fact that in most patients, lower jaw fractures are characterized by a significant severity of the clinical course, especially when the integrity of the bone is compromised in two, three or more places, there is a concussion, or there is a rupture and crushing of the perimaxillary soft tissues. Therefore, it is necessary to very carefully and in detail collect anamnesis (from the patient or accompanying person), using all available documents: a certificate, an extract from the medical history, a referral, an industrial accident report.

In case of single fractures of the lower jaw, patients complain of a feeling of pain that appears immediately after the injury, the inability to close the teeth, difficulty speaking, disruption of the act of chewing, loss of superficial sensitivity of the skin of the face and the mucous membrane of the oral cavity. In case of more severe injuries (double, triple, multiple), complaints of difficulty swallowing, especially in the supine position, and even breathing are added.

When collecting anamnesis from a victim who is in a state of alcoholic intoxication, it is necessary to take into account possible inaccuracies (intentional or unintentional) regarding the time, circumstances of the injury, duration of loss of consciousness, etc. It should be remembered that for subsequent work of a representative of the investigative bodies, the following information must be recorded in the medical history: the exact time of injury; the last name, first name, patronymic of the person who inflicted the injury and witnesses to this; where, when, by whom first aid was provided and its nature; what medications the victim took internally, subcutaneously or intramuscularly, etc.

When a patient with a complicated injury (osteomyelitis, sinusitis, suppurating hematoma, phlegmon, pneumonia, etc.) is admitted to hospital, it is necessary to find out when the complication arose, what measures were taken against it, where and by whom; at the same time, the doctor must observe deontological delicacy, especially when examining a seriously ill patient with a high body temperature, difficulty breathing, speech, etc. The anamnesis should be collected as quickly as possible in order to prevent the patient's condition from worsening and not to lose the time needed to take effective measures against complications.

Symptoms of a fractured lower jaw:

1. facial asymmetry due to soft tissue edema or hemorrhage in the area of the suspected fracture;
2. pain when palpating the bone;
3. as a rule, to varying degrees, there is a pronounced displacement and mobility of fragments (with careful bimanual examination);
4. malocclusion;
5. increasing the electrical excitability of teeth.

If the patient has injuries not only to the jaws and face, but also to other organs, the examination should be carried out together with the necessary specialists (otolaryngologist, ophthalmologist, neurologist, therapist, etc.) in order to minimize the time of examination before providing the necessary qualified assistance. Examination, palpation, probing of wounds and wound fistulas should be carried out in the dressing room, strictly observing the requirements of asepsis and antisepsis and trying to spare the patient as much as possible.

The inspection allows us to determine:

1. the nature of facial asymmetry - due to damage to bones and soft tissues, hematoma, infiltrate or edema (the boundaries of which, as well as the malocclusion, should be clearly described in the medical history);
2. the presence of ruptures in the mucous membrane of the gums, tongue, and floor of the mouth;
3. accumulation of blood clots in the face, mouth, and nasal passages;
4. leakage of cerebrospinal fluid from the ears and nose.

By means of palpation it is possible to determine the cause of facial asymmetry (edema, displacement of bone fragments, infiltrate, phlegmon, abscess, emphysema). The following palpation maneuver allows to detect a fracture of the lower jaw: the thumb of the doctor's right hand should cover the right half of the body of the lower jaw, and the index finger - the left; with light pressure on the chin there is pain in the area of the fracture of the body, angle or branch of the lower jaw. By inserting the index fingers into the patient's external auditory canals (with the palmar surface of the distal phalanges forward) and asking the patient to open and close his mouth or shift the chin to the left and right, the doctor can determine the degree and symmetry of mobility of the heads of the lower jaw. If one of them is not palpated under the finger, this indicates an anterior dislocation of the lower jaw or a fracture-dislocation of the condylar process. In case of a bilateral dislocation, the heads of the lower jaw are not palpated on both sides.

The data obtained during an objective examination of the patient (inspection, palpation, tonometry, thermometry, pulse rate determination, auscultation, percussion, etc.) are entered into the medical history. Having established a preliminary diagnosis, the doctor prescribes additional studies (if necessary) and treatment.

Since fractures of the lower jaw are often combined with a concussion or a severe or mild contusion of the brain, every patient with a fracture of the lower jaw should be consulted by a neurologist.

When examining a patient with a maxillofacial injury, attention should be paid to the pulse and blood pressure. In these cases, symptoms such as impaired consciousness, amnesia, headache, dizziness, nausea, and vomiting can be used to suspect a craniocerebral injury.

In addition, patients with fractures of the lower jaw often experience traumatic neuritis of the branches of the trigeminal nerve, which is caused by degenerative changes in the nerve fibers and is characterized by paresthesia, hyper- or anesthesia of the teeth, lower lip, etc.

In the long term, traumatic neuritis often leads to bone destruction both in the fracture zone and in areas remote from it. Therefore, timely detection (by neurological and electroodonto-diagnostic methods of examination) and treatment of neurological disorders are of great importance.

It is no less important to determine the sensitivity of microflora to antibiotics in the case of an open fracture, since all fractures of the lower jaw within the lower dental arch are infected with pathogenic microflora of the oral cavity, mainly staphylococci and streptococci, which in half of the patients are resistant to bacteriostatic drugs.

Classification of fractures of the mandible

Non-gunshot fractures of the lower jaw may be open to the outside and into the oral cavity. Fractures localized within the dental arch are usually open into the oral cavity as a result of a rupture of the gum tightly adjacent to the alveolar process. They may also be closed, especially if localized within the branch of the lower jaw.

The following types of fractures are distinguished: complete and incomplete (crack); single, double and multiple; one- and two-sided; linear and comminuted; with the presence of teeth on the fragments and in the absence of teeth. Non-gunshot fractures are almost never accompanied by the formation of a defect in the bone substance.

According to literature and our clinic, fractures of the lower jaw most often occur in the area of its angles (57-65%), condylar processes (21-24%), premolars and canines (16-18%), large molars (14-15%) and most rarely in the area of the incisors.

In practice, a fracture of the lower jaw can occur in any part of it, therefore the schematic representation of the predominant localization of fractures of the lower jaw in the area of the angle and mental openings, as well as other places of “least resistance” must be recognized as conditional.

The significant frequency of fractures in the area of the condylar processes and angles of the lower jaw can be explained by the prevalence of domestic trauma at present, in which the blow falls mainly on the area of the chin and angles of the lower jaw, i.e. in the anteroposterior and lateral directions. The lower jaw is a flat bone, but it is impossible to speak of the presence of places of least resistance of its individual sections only on the basis of the anatomical structure, without taking into account the direction and place of application of the traumatic force.

The lower jaw has the shape of an arc; in the area of the angles, large molars, branches and bases of the condylar processes, its cross-section is very thin, and in the anteroposterior direction, the cross-section of these areas is almost 3 times larger. Therefore, with blows from the side, a fracture of the lower jaw in the indicated places is possible even as a result of applying a relatively small force, and with lateral blows to the area of the angle, the wisdom tooth weakens the resistance of this area of the bone, and with blows directed from front to back, on the contrary, it increases its strength, “working” on compression.

The canine region is the place of least resistance of the lower jaw only during lateral impacts, since due to the significant length of the root, the mass of bone substance here is reduced, especially on the lingual and vestibular sides.

When struck from front to back, the canine tooth, like the wisdom tooth, “works” on compression, increasing the strength of the bone and resisting the mechanical force of impact.

The region of the upper part of the condylar process, the cross-section of which is wider than in the anteroposterior part, is a place of weak resistance to blows directed from front to back. With lateral blows, fractures occur here very rarely; they are usually localized at the base of the condylar process and have an oblique direction: from top to bottom and from inside to outside, i.e. they correspond to the structure and direction of the cortical layers of this area.

Thus, the condylar processes (area of the base and neck), angles of the lower jaw and sockets of the 83|38 teeth are the least resistant to anterior-posterior impacts and impacts from the side.

In case of an industrial injury, the traumatic object moves at a much higher speed than in case of a domestic injury. Therefore, the lower jaw is damaged directly at the site of application of the acting force, and its other parts, due to inertia, do not undergo significant deformations for fracture, rupture or compression. Due to this, industrial fractures are usually direct with crushing of a section of the jaw. If the traumatic action is relatively slow (compression of the jaw), the fracture occurs as in case of a domestic injury, i.e. not only at the site of application of force, but also in distant areas, even on the opposite side (reflected fractures).

Traumatic (domestic or other etiology) fracture of the lower jaw sometimes occurs in areas with reduced strength due to bone destruction by the above-mentioned pathological processes; fractures in the area of, for example, a radicular cyst can be either linear or comminuted.

It is very important to find out whether the fracture of the lower jaw is single or multiple, since multiple (double, triple, etc.) fractures are especially difficult to treat. Single fractures occur in 46.7%, double - in 45.6% (in the overwhelming majority - one fracture on the right and one on the left), triple - in 4.7%, multiple - in 2.1% of victims; isolated fractures of the alveolar process account for 0.9% of cases. As for victims with combined injuries to the face, jaws and other areas of the body, among them, persons with fractures of the lower jaw make up only 12.7%, upper jaws - 10.3%, both jaws - 4.5%, zygomatic bones - 12.4%, nasal bones - 4.8%, and only soft tissues of the face, teeth, tongue - 55.3%.

Single fractures of the lower jaw are usually localized between the 7th and 8th teeth, in the area of the corners, condylar processes, between the 2nd and 3rd teeth.

Double fractures are most common in the area of the canine and condylar process, canine and angle of the mandible, premolars and angle of the mandible.

Triple fractures are most often localized in the area of both condylar processes and in the area of the canine, or both condylar processes and between the central incisors.

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Diagnosis of a fracture of the lower jaw

The diagnosis is based on determining the location of the fracture and the nature of the displacement of the fragments; the displacement depends on the degree of imbalance of the traction of the masticatory muscles, the direction of the fracture gap, the number of teeth remaining on the jaw fragments, and other factors.

To clarify the diagnosis of a lower jaw fracture, it is necessary to perform an X-ray in two projections (anteroposterior and lateral) or orthopantomography. Such an examination is especially important in case of fractures of the condylar processes, branches and angles of the lower jaw, since fractures of this localization occur in every second or third victim and are often poorly contoured on X-rays, overlapping the cervical vertebrae, the branch of the lower jaw and the bones of the base of the skull.

In many cases of condylar process fractures, the correct diagnosis is established only after radiographic examination of the patient; the higher the fracture line on the process, the more indicative the layer-by-layer radiography is.

To clarify the nature of the fracture and disease of the condylar process of the lower jaw, it is very useful to use (E. N. Ryabokon, 1997) computed tomography on the SRT-100 device, and to visualize the temporomandibular joint on the Obraz-1 magnetic resonance tomograph (manufacturer - NPO Agregat).

In isolated damage to the alveolar process, only limited areas of the dental arch are displaced, which is easily detected using intraoral radiography.

When diagnosing a "jaw fracture", it is necessary to accurately determine its location, nature (linear, comminuted), presence or absence of displacement of bone fragments. It is unacceptable, for example, to formulate the diagnosis as follows: "fracture of the body of the lower jaw on the right", "central fracture of the lower jaw", "fracture of the upper jaw", etc. The diagnosis always determines the treatment method. Some understand the term "central fracture" as a fracture between the central incisors, while others - a fracture within four incisors. Where does the body of the jaw begin and where does it end? According to anatomy, the body of the jaw is its entire horizontal part from the left to the right corner. And some authors believe that the body of the jaw begins from the canine and ends at the wisdom tooth. As for fractures in the chin section of the body of the jaw, they are often called central fractures.

Depending on the localization, the following types of fractures should be distinguished.

1. median - passing between the central incisors;
2. incisor - between the first and lateral incisors;
3. canine - running along the line of the canine tooth;
4. mental - passing at the level of the mental foramen;
5. body of the jaw - most often within the sockets of the 5th, 6th, 7th teeth and the medial edge of the socket of the 8th tooth;
6. angular, that is, passing behind or near the socket of the lower 8th tooth, i.e. within the lower third of the jaw branch;
7. branches of the jaw - within its middle and upper thirds;
8. base of the condylar process;
9. cervical, or neck, passing in the area of the neck of the condylar process of the lower jaw;
10. fracture-dislocation - a combination of a fracture of the condylar process with a dislocation of the head of the lower jaw;
11. coronary - in the area of the coronoid process of the lower jaw.

Having named the fracture of the lower jaw, it is necessary to specify its localization in brackets using the conventional designation of the tooth along the socket of which it passes, or the teeth between which the fracture gap is localized.

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