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

Depending on the etiology, all defects of the lower jaw are divided into two main groups: gunshot and non-fire. The first group of defects is characteristic mainly for wartime.

[1], [2], [3], [4]

What causes the defects of the lower jaw?

In peacetime, non-firearms of the lower jaw are usually observed. They arise as a result of resection or exarticulation of the jaw (due to a benign or malignant tumor), its lengthening with the elimination of underdevelopment, after the osteomyelitis suffered or excessively extensive and uneconomical sequestrectomy, after accidental trauma, etc.

The clinical picture of the defect of the lower jaw depends on its location and extent, the presence between the jaw fragments of the scars, the presence of teeth on bone fragments and antagonist teeth on the upper jaw, the integrity of the skin in the adjacent areas, etc. According to the classification developed by VF Rudko, distinguish the following types of defects of the lower jaw:

1. defects in the middle part of the body;
2. defects of the lateral parts of the body;
3. combined defects of the middle and lateral divisions of the body;
4. defects in the branch and angle;
5. subtotal and total body defects;
6. absence of a branch and part of the body;
7. multiple defects.

BL Pavlov defects of the lower jaw divides into 3 classes and 8 subclasses:

• I class - terminal defects (with one free bone fragment);
• II class - defects during the jaw (with two free bone fragments);
• III class - double (bilateral) defects of the jaw (with three free bone fragments).

In the I and II classes the author singles out three subclasses: with preservation of the chin department, with partial (to the middle) loss and with complete loss; and in the third grade - two subclasses: with and without preservation of the chin department.

These classifications do not take into account the presence of teeth on jaw fragments, scarring between fragments, etc. Therefore, they can not help the surgeon in choosing the method for forming a seedling bed, the way of intraoral fixation of fragments after surgery, etc. In this respect, classifications that orthopedic dentists who attach great importance to the presence of teeth on the fragments of the lower jaw, as this solves the problem of fixing the fragments of the jaw and provides peace of the graft in the after tion period.

According to the classification of KS Yadrovoy, gunshot defects are divided into three groups:

1. with unstable displacement of fragments (without a shortened scar or with a slight shortening);
2. with a persistent displacement of fragments (with a shortened scar);
3. incorrectly fused fractures with loss of bone substance of the lower jaw (with a shortening of the jaw).

Each of these groups is divided, in turn, into the following subgroups:

1. single defect of the anterior part of the body of the lower jaw;
2. single defect of the lateral part of the body of the lower jaw;
3. single defect of the branch or branch with part of the body of the lower jaw;
4. double defect of the lower jaw.

In this classification, close to VF Rudko's classification, the presence or absence of teeth on fragments of the jaw's body is also not reflected.

To compile a comprehensive classification of defects of the lower jaw, which would not be bulky and convenient for application in practice, is simply impossible. Therefore, the diagnosis should indicate only the main characterological features of the defect: its origin, location and extent (in centimeters or with the orientation of the teeth). As for the other features of the defect of the lower jaw, which appear in various classifications and which undoubtedly have great significance, they should be indicated, but not in the diagnosis, but in describing the local status: cicatricial fragmentation with each other, cicatricial contraction of a short fragment jaws), the presence of an incomplete osteomyelitis process, the number and stability of the teeth on each fragment and on the upper jaw (the dental formula, detailed in the text), the presence of a skin defect in the body and branch of the chela cicatricial deformations of the tongue, vestibule and bottom of the oral cavity. Defects of the jaw, resulting from gunshot injuries, are often combined with cicatrices of the tongue and the bottom of the mouth, which makes speech very difficult. The surgeon should study the soft tissue condition in the area of the defect of the lower jaw to determine in advance whether they are sufficient to create a full-fledged graft box.

The ends of fragments of the jaw can be sharp or saw-toothed sclerotized thorns (with a bridge, as if bridged). These spines are covered with coarse scars, which can be difficult to separate from the bone, without damaging the oral mucosa. There is evidence that a false jaw joint with a bone defect histologically determines the area of newly formed bone bobs, which are, as it were, a continuation of the old sponge bunches. The neoplasm of these canals is metaplastic, and in part osteoblastic. This process is not sufficiently expressed, so the bone callus between even relatively closely located fragments stops in its development, which ultimately leads to non-fragmentation and formation of the so-called "false" joint.

The defect of the lower jaw causes severe dysfunction of chewing, swallowing and speech. With a defect in the jaw of the lower jaw, the patient suffers from a constant stunting of the tongue, an inability to sleep on his back.

If the defect of the bone is combined with a defect in surrounding tissues, there is a constant salivation.

If there is a defect in the chin, both fragments are shifted inward and upward; in the case of a defect in the lateral part of the jaw, a short (toothless) fragment is pulled upward, forward and inward, and a long fragment is pulled up and down. In this case, the chin is shifted to the sore side, and the angle of the lower jaw on this side sinks inward.

Treatment of defects of the lower jaw

Treatment of defects of the lower jaw is, as a rule, a complex surgical task, which has been solved for over 100 years by outstanding surgeons and orthopedists of various countries.

Orthopedic replacement of defects

Orthopedic replacement of defects of the lower jaw was first used by Larrey in 1838, making a silver prosthesis for the chin area. Until now, in cases where surgical treatment is postponed or seems impossible, orthopedists use various kinds of prostheses and tires, strengthened on the teeth or gums.

As for the explantation of alien materials between the fragments of the mandible in the historical aspect, it begins with rubber prostheses and wire struts, used more for immobilization than for replenishment of the defect. Subsequently, other alloplastic explants were used for this purpose: metallic (including gold) plates, acrylic preparations, for example AKR-7, polyvinyl and polyethylene sponges, prostheses from vitalium, polycrystalline, chromium-cobalt-molybdenum alloy, tantalum and other metals.

Such explants can be between the fragments of the lower jaw only temporarily, as they are not able to fuse with bone fragments. In addition, complications often occur in the form of perforations and fistulas on the mucous membrane or skin, which is why explants must be removed. Therefore, alloplastic materials are used only to temporarily replace the defects of the lower jaw in order to save the bed for subsequent osseous plastic surgery (when it can not be performed simultaneously with the resection of the lower jaw) and to prevent significant postoperative deformation in the region of the resected portion of the jaw.

In the development of bone plastic defects of the lower jaw, a number of periods can be identified during which surgeons sought methods that would save the patient from autotransplantation of the bone needed to replace the jaw defect, i.e. From an additional trauma on the "donor site" - the chest, crest of the ilium, etc. These include the methods of xeno- and alloplasty, as well as the most sparing methods of autosteoplasty of the lower jaw. Here are the main ones.

Xenoplastic replacement of defects

Xenoplastic replacement of defects of the lower jaw relieves the patient of an additional operation - borrowing bone material from the rib from him, etc. This kind of plastics began to be used as early as the beginning of the XIX century, however, due to the biological incompatibility of xeno-plastic material .

To overcome this obstacle, some authors propose to pre-treat xenogeneity with ethylenediamine, after which all the organic components of the bone dissolve and the remaining part consists only of crystalline and amorphous inorganic salts.

Alloplasty

Alloplasty of the lower jaw has been used for a long time; for example, Lexer made two such operations in 1908. But all of them ended, as a rule, with complete failure, not only because of tissue incompatibility, but also great difficulties in carrying out immediate bone transplantation from person to person. Therefore, surgeons began to resort to various methods of chemical processing and conservation of fragments of the lower jaw of a human corpse ("os purum" - "clean bone" and "os novum" - "new bone").

The experimental and clinical use of "pure bone" by E. S. Malevich (1959) according to the modified method of A. A. Kravchenko led the author to the conclusion that substitution of a subarachnoidal resection of the lower jaw (for a benign tumor), without opening the horny cavity the resulting bone defect with a "clean bone" can result in success. The obligatory nature of these conditions, as well as the complexity (multistage) and the duration of the preparation of "pure bone" grafts, predetermined the fact that this method was not widely used.

Each of the existing methods of conservation has its advantages and disadvantages. Preserved bone fragments are used for certain indications.

Substitution of large (more than 25 cm) defects of the mandible with cold- preserved bone and cartilage allografts turned out to be of little promise, according to some authors. As the results of experimental and clinical studies have shown, allografts canned with cold can not be used for secondary bone plaque if a defect of 2 cm or more is substituted for replacement. At the same time, other authors consider it expedient to use bone and cartilaginous tissue preserved at low and ultra-low temperatures for reconstructive operations on the face, as well as a good clinical and cosmetic result.

A special place among the methods of alloplasty of the lower jaw in recent years is the use of lyophilized allografts, especially taken from the lower jaw of the corpse. This material can be stored for a long time at room temperature, its transportation is simple, the body's response to transplanting such a transplant is less pronounced, etc.

The essence of the method of lyophilization lies in the sublimation of water from a pre-frozen tissue in a vacuum. Dewatering of the tissue is carried out by maintaining the equilibrium of the concentration of water vapor in the tissues and the surrounding space. With such a drying of the tissue, denaturation of proteins, enzymes and other unstable substances does not occur in it. The residual moisture of the dried material largely depends on the method of freeze-drying and equipment, and very significantly affects the quality of the transplant, and therefore, on the outcome of the transplant.

At the same time, recent searches for other ways to solve the problem of "donation" of solid plastic material for reconstructive-reconstructive operations in the face-and-facial zones have been conducted recently; for example, VA Belchenko and co-authors. (1996) have shown the successful use of perforated titanium plates as endoprostheses for extensive posttraumatic defects in the bone tissue of the brain and facial skull .

AI Nerobeev et al. (1997) consider that in patients of elderly and senile age, titanium implants may be an alternative to bone grafting, and in young patients it should be considered as a temporary provision for preserving the function of the remaining (after resection) part of the lower jaw before wound healing and as the formation of a transplantation bed for the subsequent bone plastic. Titanium mesh endoprostheses, made in the shape of the jaw, can simultaneously perform bone plastic by placing the autosty in the trough of the titanium implant.

E. U. Makhamov, S. Yu. Abdulaev (1996), comparing the results of replacement of mandibular defects with auto-, allografts and implants from glass ceramics, indicate the advantage of using the latter.

Along with this, active development of new implantation materials based on hydroxylapatite (VK Leont'ev, 1996, VM Bezrukov, AS Grigor'yan, 1996), which may be an alternative to the auto- and allogeneic bone .

The success of the application of various forms of hydroxylapatite and materials based on them will depend on the rates of development of differentiated indications for their use in the experiment and in the clinic; for example, AS Grigoryan et al. (1996) in experiments on animals have proved the high promise of using a new composition with structured collagen, powder and granulate of hydroxylapatite (MP-2) in maxillofacial surgery.

Hydroxylapatite, the average composition of which is usually represented as Ca ₁₀ (PO ₄ ) ₆ (OH) ₂, has already been used to replace defects in hard tissues, hard organs or parts thereof (joints, bones, implants), as part of composite biological materials or stimulator of osteogenesis (VK Leont'ev, 1996). However, "in recent years, a number of controversial issues have accumulated, including those related to some negative experience with the use of this material.