RU2332189C2 - Device for lower jaw condylar process replacement - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: device includes a block body, a body with projection for interaction with joint socket surface, at least a couple of block body fixation units for attaching it to lower jaw, and body movement and fixation unit for interaction with joint socket surface against the block body. The body for interaction with joint socket surface is a single block, its installation enables longitudinal movement against the block body. The body movement and fixation unit interaction with joint socket surface against the block body includes a rod element mounted so as to move freely in the longitudinal hole in the block body. The rod element has a hole with a screw connected to it by threaded coupling, the screw featuring device of fixation against the block body without longitudinal movement capability, and at the opposite side of the rod element the body for interaction with joint socket is positioned. The screw head of rotational power tool can be accessed by percutaneous puncture.

EFFECT: compensation of mandible ramus bone stock growth at the sound side due to endoprosthesis length increase at the operable side without its replacement.

10 cl, 36 dwg, 1 ex

Description

The invention relates to medicine, namely to maxillofacial surgery, and can be used to replace congenital and acquired defects of the condylar process of the lower jaw in children and adults resulting from underdevelopment of the facial skeleton, surgical interventions for neoplasms and traumatic injuries of the condylar process of the lower jaw, as well as during endoprosthetics of the temporomandibular joint with ankylosis and deforming arthrosis.

A special place among patients with the above pathology is occupied by children and young people, in whom diseases occur during the formation of the facial skeleton, the intensive growth of bone tissue of the lower and upper jaw, as well as the brain skull and are accompanied by a violation of the growth zones, leading to deformation of the bones of the face, and a decrease or complete absence of movements of the lower jaw. These changes inevitably lead to a decrease in chewing function, changes in breathing and speech, aesthetic defects, which not only leads to secondary diseases, but also complicates the social adaptation of the young man in modern society.

The tactics of treating patients with the pathology listed above have their own characteristics depending on the specific clinical situation, stage of the process, as well as subjective complaints and requests of the patient. Along with this, there are common points in the treatment of young patients with diseases of the articular process of the lower jaw and the temporomandibular joint as a whole (hereinafter - TMJ).

The first generalizing point is that as a result of congenital underdevelopment, an inflammatory process or trauma, a defect in the bone and soft tissue anatomical elements of the maxillofacial region, namely the condylar process of the lower jaw or TMJ as a whole, often occurs (here we mean the pathology of not only the condylar process, but also the articular fossa). Similar defects also arise as a result of surgical treatment of benign and malignant neoplasms, deforming arthrosis, TMJ ankyloses. In this regard, the surgeon is faced with the task of not only eliminating the pathological process, but also restoring the function of the lost elements of the lower jaw and joint using various biological and synthetic materials.

Note: in accordance with the generally accepted terminology in medicine, the word "defect" in this application means a partial or complete absence of an organ or part thereof, specifically a partial or complete absence of either the articular process of the lower jaw, or the joint as a whole.

The second point is that in children and young patients after reconstructive surgery in the TMJ, bone growth zones are violated on one or two sides, which leads to the occurrence of secondary deformations of the supporting and soft tissues of the face, occlusion changes, aesthetic disorders, which progress as the patient grows up and makes it necessary to conduct repeated surgical treatment in order to correct the element by which the defect was replaced and to eliminate the accompanying changes in the braids GOVERNMENTAL and soft tissues.

Ankylosis of the temporomandibular joint is one of the most common among these diseases, leading to deformation of the facial skeleton in young people. As an example for the analysis of treatment methods that are used today and in recent decades, we will consider this pathology in detail, given that it can be a consequence of both traumatic injuries of the terminal section of the lower jaw and deforming arthrosis.

TMJ ankylosis is characterized by persistent changes in the joint, leading to a significant limitation or complete loss of mobility due to the growth of fibrous or bone tissue. Ankyloses can be either bilateral or unilateral. The latter are the most difficult, since in children with a lesion of one of the TMJs due to the death of the air conditioning zone of the lower jaw, hypoplasia (underdevelopment) of one half of the skull is subsequently observed, which leads to the formation of persistent combined deformation of the supporting and soft tissues of the face and bite. A key component of this type of change is the lower jaw. A characteristic feature of such deformations is the combination of an underdeveloped and deformed one half of the jaw with an overdeveloped and also deformed other half, which as a result leads to malocclusion, teething, and underdevelopment of the entire lower and middle area of the face, including soft tissues (N.A. Plotnikov, A .A. Nikitin, All TMJ allotransplantation in the surgical treatment of 1989 ankylosis) (see Fig. 1 and Fig. 2).

Treatment of patients suffering from TMJ ankylosis is a difficult task of reconstructive surgery of the maxillofacial region. The relevance of this problem is evidenced by the fact that the development of methods for treating this pathology has been carried out by specialists from many countries for over 150 years.

The first methods of treatment consisted of linear dissection and removal of the bone in various parts of the lower jaw in order to restore its mobility. Such operations almost always ended with a relapse of ankylosis, disturbed the bite and increased deformation of the jaw.

At a later time, the idea of interposition of various organic and inorganic materials between bone fragments after an osteotomy began to be used to eliminate ankylosis: chewing muscle on a nutritional leg, transplantation of adipose tissue, cartilage, wide fascia of the thigh, periosteum, bioplastics, as well as gaskets and caps, which planted on the fragment of the branches of the lower jaw. An osteotomy with interposition of autoplastic material was first proposed by Verneuil (1860), using a wide fascia of the thigh. Sklifosovsky N.V. (1881) used adjacent soft tissues as a gasket between osteotomized fragments; Helferich (1894) used a temporal muscle flap for the same purpose, and finally Blair and Murphy (1913) used the temporal fascia. In 1950, Limberg A.A. suggested placing between osteotomized tissue fragments of the epidermal filatov stem.

To suppress bone regeneration and prevent relapse of ankylosis, methods of chemical and thermal processing of fragments were used. However, all of them did not relieve relapses and only led to the creation of a false joint with the aim of achieving mobility of the lower jaw in any way. Along with the elimination of the deformation of the lower jaw, the violation of chewing function and occlusion in the long term, no importance was attached. Such patients required repeated surgical treatment at an older age, when the growth of facial bones ended.

With the accumulation of practical experience of doctors, improvement of new methods of surgical treatment and the widespread introduction of antibacterial drugs into clinical practice by surgeons, the method of bone grafting of terminal defects of the lower jaw and TMJ with the following grafts has become widely used.

1. Bone grafting with an autograft (autotransplantation should be understood as transplantation of one’s own organs or tissues taken from one site and transplanted to another from the same person (animal). The most effective use of this type of grafting is a rib or iliac crest).

Bone grafting can be simultaneous when the defect is replaced immediately after the removal of pathologically changed tissues, and delayed when the defect is replaced in the second stage of surgical treatment. In both cases, the first stage of the operation is the preparation of the receiving bed for the graft, which should be of the appropriate size, not have inflammatory changes and allow the graft to be adequately fixed to the lower jaw. At the same time, the second team of surgeons is taking the graft from the donor zone. The latter, using various tools, is brought to the desired shape and size, and then installed in the place of the defect and fixed with one end to the lower jaw with a metal structure (in accordance with the clinical situation, a titanium plate, mesh or bone suture can be used), and the other end is placed again formed articular fossa (A. A. Nikitin. Autoplasty of the articular process of the lower jaw with a bone-cartilage costal graft. Moscow, 1971).

The main advantage of this method of replacing a bone defect is the ability to obtain a transplant of sufficient volume from a fully biologically compatible bone tissue. However, it has a number of disadvantages, we list them.

A. The need for additional surgical treatment in the donor area, which is an additional trauma for the patient and increases the time of the operation.

B. It is difficult to create an anatomical form of the graft that is ideally suited to the replaced articular process; therefore, with autoplasty, it is not always possible to obtain the desired restoration of function and aesthetic result.

B. The possibility of resorption and suppuration of the graft in the postoperative period.

D. The need for repeated surgical treatment to eliminate the secondary deformation of the facial skeleton in children and young patients in connection with the inevitable violation of the growth zones during the first stage of treatment.

These shortcomings prompted doctors and scientists around the world to ask about the search for a new plastic material and method for replacing defects in which the transplant would retain its biological qualities to a certain extent, ensure restoration of the anatomy of the lower jaw, and obtaining it would not be associated with additional surgical intervention . A breakthrough in this area was the emergence in the early 50s of the last century of the method of preserving bone tissue by lyophilization (this method is based on deep freezing of the tissue with subsequent drying), this gave an impetus to the development of the next type of treatment for ankylosis and condylar process defects of various etiologies.

2. Bone grafting with a lyophilized allograft (allotransplantation refers to the transplantation of organs or tissues between two individuals that are genetically different from one person to another, from rabbit to rabbit, etc.) For the first time in maxillofacial surgery, lyophilized bone tissue to replace the defect of the lower jaw applied Blackstone in 1954. Starting in 1959, in our country, the Moscow Regional Research Institute has successfully applied the method of replacing the condylar process defect of the lower jaw with lyophilized allostomy (N. A. Plotnikov. Homoplasty of the lower jaw with lyophilized bone graft. Moscow, 1968). In the future, it was constantly improved, which made possible the transplantation of not only the terminal section of the lower jaw, but also the full temporomandibular joint (A.A. Nikitin. Alloplasty of the temporomandibular joint. Moscow, Ph.D. medical sciences, 1987. ) The use of lyophilized allografts eliminated the need for additional traumatic surgery for the patient to take donor material (as canned bone is used), and also made it possible to select a transplant for the transplant, which in size and anatomical shape fully corresponds to the replaced organ. At the same time, the likelihood of resorption and suppuration of the graft in the postoperative period, as well as secondary deformation in children and young people due to violation of growth zones, which required repeated surgical treatment, remained.

Thus, the reconstruction of the temporomandibular joint using auto- and allografts has undergone significant changes in connection with the development of surgical technique. From the formation of a false joint using the wide fascia as an insulating element, and then bone and bone-cartilage grafts, the surgical treatment technique has evolved to the use of allografts, including all elements of the TMJ, as well as the use of free revascularized autografts of other joints (metatarsal phalangeal and metatarsal cuboid of the third toe). The use of autografts, although it allows creating conditions for restoring the movement of the lower jaw and eliminating deformation, however, it does not always give a stable result, it requires additional surgical trauma in the donor zone, and when using microvascular technology, there is a need for special surgical equipment and qualifications of surgeons, which is essential limits the widespread use of this technique. The use of allografts implies the availability of an accessible tissue bank and at the same time does not solve the problem of tissue incompatibility and the possibility of infection (N.A. Plotnikov. Bone grafting of the lower jaw. 1979, Moscow, p. 254). Buck (1989) based on mathematical calculations concluded that, subject to strict selection of HIV antibodies and histological examination of donor tissues, the chance of receiving a transplant from an HIV-infected donor is 1: 1,000,000; on the other hand, if appropriate measures are not taken, the risk increases to 1: 161.

3. Endoprosthetics

In parallel with bone grafting, the development and improvement of methods for treating pathology of the lower jaw and TMJ, which was based on endoprosthetics using various implants and mechanisms from materials of various origins, continued.

Note: endoprosthetics should be understood as replacing the organ (bone) lost due to a disease or surgical treatment by installing a prosthesis made of artificial material, which is designed to restore not only the shape, but also the function of the lost organ. Practical experience with the use of endoprostheses of both large and small joints has more than a hundred years.

The beginning of this path was laid by Helferich (1894) when, in the treatment of ankylosis, he installed interpositional implants in the osteotomy sites of the ankylosed area. The author’s technique included osteotomy and the creation of a gap between the branch of the lower jaw and the temporal bone, which allowed the introduction of various materials, connected mainly by wire to the branches of the lower jaw. The problems that occurred when using this technique included: rapid wear of the implant with perforation, difficulties in modeling the implant during surgery, as well as significant instability of both the implant and the movements of the lower jaw.

The second half of the 20th century marked the beginning of a new stage in the endoprosthetics associated with the use of plastics, in particular, Sanders (1977) and Parmer (1972) implants are known, based on the use of silastic pads that were installed in the area of the forming osteotomy. Semkin V.A. et al. (1997) used a silicone cap attached to the condylar process stump.

Eggers, who used tantalum gaskets in 1946, and Robinson, who applied stainless steel in 1960, began the use of metals in endoprosthetics for TMJ elements. In parallel, new approaches to the treatment of ankylosis were developed, requiring resection of the altered tissues. This method involves the installation of a condylar process endoprosthesis defect in place either separately or together with a TMJ joint fossa prosthesis consisting of a base, neck and head. The following are a few examples of the condylar process endoprostheses.

1. The evolution product of the above method was the Christensen I implant (1965), which is made on the basis of dummy skulls made of vitallium (an alloy of chromium, cobalt and molybdenum) and has a head made of acrylic. This method allows you to restore the normal height of the lower jaw branch and its mobility. It is illustrated in Fig. 3.

2. Kent-Vitek, 1972, uses a chromocobalt alloy as a material for the manufacture of an articular process endoprosthesis (it was also used with a proplast articular fossa implant). It is illustrated in Fig. 4.

3. In 1976, Spiessel applied the condylar process endoprosthesis, later named "AO / ASIF", also known as "SYNTHES". The spherical head was inserted into the natural articular fossa. For additional fixation of the product, a spike was used on the base of the condyle head, and titanium was used as the material. It is illustrated in Fig. 5.

4. In 1980, Boyne presented a series of clinical cases using condyle endoprostheses consisting of a polyoxymethylene-based head (known as “DELRIN”) mounted on a perforated titanium base. In 1987, the design was changed by the author: the head began to move on a titanium hinge, and the base was a self-tapping pin. It is illustrated in Fig. 6.

Over the past decades, in the process of developing new bioinert materials for medical purposes and metal processing methods, the aforementioned products have been improved. In particular, Christiansen RW presented a type II endoprosthesis with a strengthened base, due to fractures of the first variant in 7% of cases (Fig. 7). TMJ prosthetics systems are also known under the brands "TECHMEDICA" (Fig. 8) and "BIOMET-LORENZ" (Fig. 9), using an articular fossa implant based on high molecular weight polyethylene as a joint part.

In Russia, in recent years, domestic endoprostheses of the condylar processes of the lower jaw have been developed and are successfully used. Particularly noteworthy are the products of KONMET CJSC, created jointly with the Central Research Institute of Dentistry of the Russian Ministry of Health. Endoprostheses, components and tools are approved for use in clinical practice and are made of titanium according to European standards.

The first version of the condylar process endoprosthesis has a head in the form of a ball with a diameter of 0.8 cm and an anatomically curved neck, which goes into the fixing device (base), made in the lightweight version in the form of a U-shaped mesh 1 mm thick, equipped with holes for mini-screws, with the help of which the endoprosthesis is fixed to the jaw branch.

In the second embodiment, the head of an ellipsoidal (anatomical) shape is rigidly fixed to a reinforced titanium plate, which can replace defects of the lower jaw of a greater length.

When using endoprostheses in patients with TMJ ankylosis, surgical intervention is as follows. Under general anesthesia, a skin incision is made that borders the angle of the lower jaw. Tissues are dissected in layers to the bone, cut off from the attachment point of the muscle and skeletonize (release from soft tissues) the branch of the lower jaw all the way from the corner to the head of the condylar process or to the point of fusion of the branch with the temporal bone in case of ankylosis. Next, produce a horizontal osteotomy of the lower jaw (separation) below the border of the altered tissues. If it is impossible to remove a conglomerate of altered tissues in the joint area from the submandibular access and form the articular fossa, an additional precarp approach is performed. After the formation of a new articular fossa, an endoprosthesis is inserted from the submandibular incision using a drill and a milling cutter. Its head is installed in the newly formed articular fossa, and the base is rigidly attached to the lower jaw with mini-screws. If necessary, the endoprosthesis can be supplemented with an implant of the articular fossa, which is usually made individually from high molecular weight polyethylene and is attached to the temporal bone using mini-screws and bone cement.

In conclusion, a review of methods for replacing defects of the articular process of the lower jaw should be based on the method of compression-distraction osteogenesis, based on the method of G. A. Ilizarov. Its essence lies in the fact that in the presence of an end defect of the lower jaw, an osteotomy (separation) is performed in the area of the preserved bone fragment, then, using a special apparatus, these fragments are compressed (squeezed) together, which stimulates bone growth in this area. Further, these fragments begin to stretch in the right direction, thereby increasing the volume of bone tissue. This allows you to replace bone defects of various lengths by growing the patient’s own bone tissue. The devices used for this are called compression-distraction.

In our country and abroad, various modifications of such devices are successfully applied. This method is one of the most promising for the replacement of bone defects of various localization. Along with this, he, like others, is characterized by limitations in use, namely, the patient needs to wear a device rigidly fixed in bone tissue for several months or more and periodically carry out the correction of the tensile force with the help of a doctor. This makes the patient feel discomfort, which is especially characteristic of children and young patients. The likelihood of infection of the postoperative region also increases due to the presence of additional entrance gates of infection at the site of fixation of the device. After growing bone regenerate to the required size, the apparatus has to be removed, for which a second surgical intervention is necessary.

From the foregoing, we can conclude that all the described methods for eliminating the defects of the condylar process of the lower jaw are worthy of attention and are relevant at the present time. Each of them is selected by the maxillofacial surgeon individually for a specific patient and clinical situation. Scientists and doctors around the world do not stop working on improving methods for surgical treatment of lower jaw pathology and TMJ, reducing their morbidity and shortening the process of rehabilitation after treatment.

One of the general problems of the treatment of condylar process defects by endoprosthetics in children and young people is the development of secondary deformation of the bones and soft tissues of the face in the period after the first stage of endoprosthetics. The reason for this is a violation or absence of bone growth zones as a result of a congenital disease, trauma or dysplastic process. The development of such a deformity forces surgeons to resort to repeated, sometimes repeated, surgical treatment to correct the deformity or replace the endoprosthesis with a similar, but more appropriate in size, patient's age. In addition to physical difficulties, a young man has problems of social adaptation in society, which leads to disability.

The above methods and devices are also provided in the following sources of information: 1) Peter D. Quinn dmd, md, Atlas of temporomandibular joint surgery, 1998, p. 170-212; 2) Jan-Paul van Loon, Lambert G.M. de Bont, Gttrt Boering, 1995, Evaluation of Temporomandibular joint proteses; 3) V.M. Bezrukov, I.A. Semkin, Yu.N. Chergestov, 2000, Diseases and injuries of the TMJ; 4) William C. Donon DMD, MA, Total temporomandibular joint reconstruction, 2000.

A device for replacing the condylar process, including a block-shaped body and a body for interacting with the articular fossa, the body for interacting with the articular fossa is made stretching approximately along the longitudinal axis from one end of the block-like body with a protrusion at the end, and, in addition, the device is provided at least a pair of means for securing the attachment of the block-like body to the lower jaw. This device is shown in Fig. 8 as the product "BIOMET-LORENZ". It is taken as a prototype of the claimed invention, since it is closest to it in the aggregate of common essential features and the achieved technical result.

Its disadvantage, like all of the above analogues, is the inability to correct (change) the longitudinal size of the device, which does not allow to correct the secondary deformation of the facial skeleton in young and children as a result of bone growth on the healthy side without repeated surgical intervention in full. In other words, the drawback is the need for repeated surgical treatment to eliminate the secondary deformation of the facial skeleton in children and young patients in connection with the inevitable violation of the growth zones during the first stage of treatment.

The technical task of our invention is to provide a device for eliminating defects of the condylar process of the lower jaw of various origins in children and adolescents, which avoids reoperation after the primary replacement of the defect by developing a device for replacing the condylar process (endoprosthesis), the design of which would allow changing its size in the postoperative period with the help of simple outpatient manipulation.

The stated technical problem is solved in that the device for replacing the condylar process includes a block-shaped body and a body for interacting with the articular fossa, and the body for interacting with the articular fossa is made stretching approximately along the longitudinal axis from one end of the block-shaped body with a protrusion at the end, in addition, the device provided with at least a pair of means for securing the attachment of the block-like body to the lower jaw, and according to the invention, the body for interacting with the surface of the articular pits designed separate unit and is mounted for longitudinal movement relative blokoobraznogo body and equipped with means for moving and locking the body to interact with the surface of the glenoid fossa relatively blokoobraznogo body.

The technical result of the invention is to increase the effectiveness of treatment by eliminating the re-operative intervention in full after the initial replacement of the defect and the possibility of correcting the height of the condyle process in the course of treatment by outpatient manipulation.

In addition, we consider it necessary to highlight the following development and / or refinement of the totality of its common essential features related to particular cases of performance or use.

They are caused by the fact that, generally speaking, it is possible to construct several means of movement and fixation of the body that are different in design for interaction with the surface of the articular fossa relative to the block-shaped body. The applicant himself developed several modifications.

However, according to the applicant, the construction according to which the means of moving and fixing the body for interacting with the surface of the articular fossa relative to the block-shaped body contains a rod-shaped element mounted with the possibility of longitudinal movement in a longitudinal hole made in a block-shaped body, and in the rod-shaped element there is a hole in which a screw is connected connected to it by a threaded connection, provided with means for fixing the position of the screw A flax-like body without the possibility of longitudinal movement, and on the opposite side on the rod-shaped element there is a body for interaction with the surface of the articular fossa.

The rod-shaped element and the longitudinal hole in the block-shaped body in which it is installed may have a different shape. However, the most appropriate design, in which the element is rod-shaped and a longitudinal hole in the block-shaped body in which it is mounted, is made flattened. This minimizes the height of the device, and also prevents the rotational movement of the rod-shaped element inside the hole in the block-shaped body.

Means for fixing the position of the screw relative to the block-like body without the possibility of longitudinal movement can be designed differently. However, the most desirable design, in which it contains an element, in particular a key, for example, a U-shaped, which is mounted in one part in a block-shaped body, and the other part is placed in the annular groove of the screw.

It is preferable to equip the device with a means to limit the longitudinal movement of the body to interact with the surface of the articular fossa relative to the block-shaped body. For example, this node may contain an element, in particular a pin, which is fixedly connected to the block-shaped body by one part and the other part is located in the longitudinal recess of the rod-shaped element, and the recess does not reach at least one of the ends of the rod-shaped element.

It is advisable that each means to ensure the attachment of the block-like body to the lower jaw contains a screw, the rod of which is placed in the through hole of the block-like body, and the cap covers the surface of the block-like body. In this case, it is desirable that at least one of the through holes of the block-shaped body is made of elongated shape.

In addition, it is preferable that the means of moving and fixing the body to interact with the surface of the articular fossa relative to the block-shaped body be mounted with the possibility of access to the screw head of the rotary drive tool by percutaneous puncture.

The invention is illustrated by drawings.

Figure 1 shows a device for replacing at least part of the condylar process, general view, axonometry (for the left jaw).

Figure 2 is the same longitudinal section (for the left jaw).

Figure 3 is the same plan view (for the left jaw) (screws not shown).

Figure 4 is the same plan view (for the right jaw) (screws not shown) (mirror image).

Figure 5 is the same, section aa of figure 2.

In Fig.6 is the same, section bB of Fig.3.

In Fig.7 shows an enlarged separate image of a part of the device, limited by a circle marked with the letter B in Fig.6.

On Fig depicted separately a block-like body, a longitudinal section (for the left jaw).

Figure 9 is the same plan view (for the left jaw).

Figure 10 is the same, section GG figure 9.

Figure 11 shows an enlarged individual image of a part of a block-like body, limited by a circle marked with the letter D in figure 10.

12 is the same plan view (for the right jaw) (mirror image).

On Fig depicts a rod-shaped element, a longitudinal section.

On Fig - the same, end view along arrow E.

On Fig - the same view in plan.

In Fig.16 is the same, section FJ of Fig.15.

On Fig shows a screw, side view.

On Fig - the same, end view along arrow I.

On Fig shows a body for interaction with the surface of the articular fossa, side view (for the left jaw).

In Fig.20 is the same, end view along arrow K (for the left jaw).

In Fig.21 is the same, end view in the direction of arrow L (for the left jaw).

In Fig.22 is the same plan view (for the left jaw).

In Fig.23 is the same, plan view (for the right jaw) (mirror reflection).

On Fig shows a key, a side view.

In Fig.25 is the same, section MM of Fig.26.

On Fig shows the pin, side view.

Photo 1 shows the claimed device.

In addition, the applicant provides nine graphic drawings (Fig. 1-9) illustrating the treatment methods and designs indicated in the above brief overview of the prior art, which are given for the convenience of the examination, since in this case there is no need to search for analogues and prototypes, some of which are a bibliographic rarity. In the above brief overview, when analyzing a method or design, a specific reference is made to the illustration illustrating this method or design.

Figure 1 shows the lower jaw of a person without a defect.

Figure 2 shows the lower jaw with a defect in the bone and soft tissue anatomical elements of the maxillofacial region, namely, the condylar process of the lower jaw or TMJ as a whole (the pathology of not only the condyle process, but also the articular fossa).

Figure 3 shows the Christensen I implant (1965).

Figure 4 shows an endoprosthesis of the articular process (Kent-Vitek, 1972).

Fig. 5 shows the condylar endoprosthesis, later named "AO / ASIF", also known as "SYNTHES" (1976, Spiessel).

Figure 6 shows the condyle endoprosthesis developed by Boyne.

Figure 7 shows a type II endoprosthesis with a reinforced base (Christiansen RW).

Fig. 8 shows a system for prosthetics of the TMJ brand TECHMEDICA.

Fig. 9 shows a system for prosthetics of the TMJ brand "BIOMET-LORENZ".

Description of the claimed device in statics

The device 1 for replacing at least a part of the condylar process includes a block-shaped body 2 and a body 3 for interacting with the surface of the articular fossa (Fig. 1). The body 3 for interacting with the surface of the articular fossa is made extending from one end of the block-like body 2 with a protrusion 4 at the end, elongated at least in the transverse direction from the longitudinal axis of the block-shaped body. In addition, the device 1 is equipped with several means 5 for securing the attachment of the block-like body 2 to the lateral (external) surface of the lower jaw branch 6. The protrusion 4 is installed in the articular fossa 7 of the temporal bone, and the said fossa can be both natural and artificial. The body 3 for interacting with the surface of the articular fossa is designed as a separate unit and mounted with the possibility of longitudinal movement relative to the block-shaped body 2. To ensure this, the device 1 is equipped with means 8 for moving and fixing the body to interact with the surface of the articular fossa relative to the block-shaped body.

The design of the means 8 of moving and fixing the body to interact with the surface of the articular fossa relative to the block-shaped body may be different. The applicant has developed several modifications.

The following is one of the most preferred options (Fig.2-7).

The body moving and fixing means 8 for interacting with the surface of the articular fossa relative to the block-shaped body contains a rod-shaped element 9 (shown separately in FIGS. 13-16), mounted with the possibility of longitudinal movement in a through longitudinal hole 10, made in a block-shaped body 2. Block-shaped body 2 is shown in detail separately in FIGS. 8-12. The rod-shaped element 9 has a hole in which a screw 12 connected to it by a threaded connection is placed (shown in detail separately in Figs. 17, 18). To do this, on a part of the inner surface of the element 9 there is a screw thread 13 that interacts with a screw thread 14 of the screw 12. The screw 12 is provided with means 15 for fixing the position of the screw relative to the block-like body without the possibility of longitudinal movement (shown in detail separately in Figs. 24, 25). On the opposite side, at the end of the rod-shaped element 9, for example, a body 3 is rigidly fixed by welding to interact with the surface of the articular fossa (shown in detail separately in Figs. 19-23).

The block-shaped body 2 is made flattened (flattened) to minimize the height of the protrusion of the device above the bone after installation on the lower jaw. The through longitudinal hole 10 in the block-like body 2 is also made of a flattened shape. A rod-shaped element 9 is inserted into the through longitudinal hole 10. This rod-shaped element 9, like the through longitudinal hole 10, is made flattened (flattened) to prevent its displacement relative to the block-shaped body 2 around its own longitudinal axis. As previously noted, the rod-shaped element 9 is mounted with the possibility of longitudinal reciprocating movement in the specified through longitudinal hole 10.

Consider separately the means 15 for fixing the position of the screw relative to the block-like body without the possibility of longitudinal movement. It is shown in detail in Fig.24, 25, as well as in Fig.2 and Fig.5. The means 15 for fixing the position of the screw relative to the block-like body without the possibility of longitudinal movement contains an element in the form of a dowel 16, which is, in particular, a U-shaped plate. The key 16 is placed in the groove 17 of the block-like body 2, and its other part is placed in the annular groove 18 of the screw 12. Due to this design, when the screw is rotated, it will not move in the longitudinal direction relative to the block-shaped body 2. But since this screw 12 is engaged with its screw thread 14 with a screw thread 13 of the rod-shaped element 9, when turning it, remaining in one place due to the indicated screw threads, it will move the rod-shaped element 9 in the longitudinal direction together with rigidly fixed to it the end of the body 3 to interact with the surface of the articular fossa, and its direction of movement will be determined by the direction of rotation of the screw 12, namely, when the screw 12 is rotated clockwise, the rod-shaped element 9 will move in one direction, counterclockwise in the opposite direction. To rotate the screw 12, it has a head 19, which may have a different shape for the corresponding rotary drive tool, such as a screwdriver.

The device 1 is additionally equipped with a means 20 for limiting the longitudinal movement of the body to interact with the surface of the articular fossa relative to the block-shaped body. This tool contains an element, in particular, made in the form of a pin 21, which is separately shown in detail in Fig.26. The pin 21 is fixedly connected to the block-shaped body 2 by one part and the other part is located in the longitudinal recess 22 of the rod-shaped element 9, and the recess does not reach at least one of the ends of the rod-shaped element 9 (Fig. 15). Thanks to the means 20, the longitudinal movement of the rod-shaped element 9 is limited together with the body 3 rigidly fixed thereon for interacting with the surface of the articular fossa relative to the block-shaped body 2, and thereby the rod-shaped element 9 is prevented from falling out of the opening 10 of the block-shaped body 2.

Let us now consider separately each means 5 for securing the attachment of the block-like body 2, which, as noted earlier, is intended to ensure the attachment of the block-like body 2 to the lateral (external) surface of the lower jaw branch 6. The tool 5 contains a screw 23, the rod of which is placed in the through hole 24 of the block-like body 2, and the cap 24 covers the surface of the block-like body 2. In this case, at least one of the through holes of the block-like body is made of oblong shape. This hole is indicated by the position 25. The implementation of the oblong shaped hole is intended for the convenience of positioning the device 1 (endoprosthesis) on the lower jaw during the operation.

The implementation of the cut-off angle 26 also aims to facilitate the installation of the device during the operation.

The contour of the cut-off angle 26 is made along the anteroposterior and posterior-inferior angles to ensure maximum positioning amplitude along the height of the lower jaw branch and to exclude the protrusion of the base beyond the edge of the lower jaw. The outer surface of the block-like body 2 has an irregular contour, providing a minimum thickness of the structure to reduce the impact on soft tissues and to make it less noticeable. Its lower surface is flattened, which provides hard contact with the bone.

The device has right and left options for the execution of a block-like body 2 and body 3 for interaction with the articular fossa, respectively, intended for installation on the right or left side of the face, as well as from the bite.

The degree and direction of bending of the body 3 for interaction with the articular fossa with the protrusion 4 depend on the clinical situation and anatomical features. They, like the block-shaped body 2, can have right and left modifications, and can also be made in the shape of a ball.

The block-shaped body 2 has other features not mentioned. In particular, for rigidly securing the pin 21 therein, a through hole 27 is made in the block-like body 2, into which the pin is inserted and welded, for example, by micro-welding.

For the convenience of using the device after the operation, it is very important that the means 8 for moving and fixing the body to interact with the surface of the articular fossa relative to the block-like body is mounted with the possibility of access to the screw 12 of the rotary drive tool by percutaneous puncture.

Device assembly

To assemble the device 1, first, the screw 12 is screwed with a screw thread 14 into the screw thread 13 inside the hole 11 of the rod-shaped element 9. Then, the resulting assembly is inserted into the hole 10 of the block-shaped body 2 and fixed in it with a key 16, inserting it into the groove 17 so that it fits into the annular groove 18 in the screw 12 with the bottom. When the assembly is inserted, it is oriented in such a way in the block-shaped body that the longitudinal the recess 22 was opposite the through hole 27 in the block-shaped body 2. Then the screw 12 is started to rotate until the opposite end of the element 9 leaves the block-shaped body 2. Then, the end 29 of the body 3 is inserted into the hole 11 of the outgoing end 28, followed by welding. Then insert the pin 21 into the through hole 27 in the block-like body 2 so that the end of the pin 21 fits into the longitudinal recess 22. Then, the pin is welded to the block-like body 2.

Device operation

When the screw 12 is rotated, it will not move in the longitudinal direction with respect to the block-shaped body 2, since the key 16 prevents this. But since this screw 12 is engaged with the screw thread 13 of the rod-shaped element 9 with the screw thread 13, it remains at one at the expense of the indicated screw threads, the rod-shaped element 9 will move in the longitudinal direction together with the body 3 rigidly fixed at its end to interact with the surface of the articular fossa, and its direction of movement is determined by the direction of rotation of the screw 12, namely when the screw 12 is rotated clockwise rod-shaped member 9 is moved in one direction, counter-clockwise - in the opposite direction. To rotate the screw 12, it has a head 19, which may have a different shape for the corresponding rotary drive tool, such as a screwdriver.

Planning the operation for installing the claimed device (hereinafter referred to as the endoprosthesis)

In recent years, surgeons have appeared in the arsenal of techniques to simulate surgery using an individual artificial model of the patient’s skull, which corresponds to the structure of the bones of his face to the nearest millimeter. The skull model is made of plastic by laser stereolithography using computer data, which is obtained after the patient undergoes a spiral computed tomography in 3D projection with the data stored on a digital medium.

The technique of the operation to install the endoprosthesis

Under general anesthesia with intubation of the patient through the nose, a skin incision is made in the submandibular region, bordering the angle of the lower jaw, the tissues are dissected in layers to the bone. Further, the branch of the lower jaw is skeletonized (freed from soft tissues) from the angle to the affected head of the condylar process or conglomerate of bone tissue in case of ankylosis, or to the border of the defect present at the time of surgery. In the presence of a pathologically altered head of the condylar process or ankylosed temporomandibular joint, a horizontal osteotomy of the lower jaw branch is made below the border of the altered tissues. If the conglomerate of ankylosed tissues of the joint cannot be removed from the submandibular access, an additional precarp approach is performed (skin incision is made parallel to the front edge of the tragus of the auricle). With this access, the area of the articular fossa of the temporal bone is exposed, after which the altered tissue of the joint is removed. Further, if the clinical situation requires this, it becomes possible to form a new articular fossa, which can also be made of artificial material (titanium, high molecular weight polyethylene, etc.). At the next stage, the external side of the lower jaw branch is machined with a drill and a bone cutter, the purpose of which is to create the most flat surface for the most dense contact of the base of the endoprosthesis with bone tissue.

Then, through the submandibular access, an endoprosthesis is inserted (previously, the body 3 for interaction with the articular fossa (hereinafter, for brevity, the endoprosthesis head) is brought into position with the help of a screw 12 and a screwdriver in which the body 3 is extended 5 out of the body for interaction with the articular fossa mm). The head of the endoprosthesis is inserted into the articular fossa, and the block-like body 2 (hereinafter, for short, the base) is located on the outer surface of the lower jaw branch so that the location of the lower jaw relative to the upper one in the anteroposterior direction corresponds to a normal bite or subsequently allows it to be corrected with orthodontic treatment (bite control during surgery is carried out through the oral cavity). Next, a preliminary fixation of the endoprosthesis on the jaw is carried out as follows: through the hole of an elongated shape 25 in the bone tissue, a hole is made using a drill or a bur of an appropriate size into which the self-tapping screw 23. sagittal (lateral) plane, taking into account the height of the lower jaw branch on a healthy (opposite side), and also taking into account the magnitude of the angle formed behind the bottom edge of the branch and the lower edge of the jaw on the healthy side.

After final positioning of the base of the endoprosthesis on the lower jaw, the latter is rigidly fixed to the bone surface using the maximum possible number of screws 23, which are screwed into the holes in the bone that were previously marked with a drill or boron.

After the base of the endoprosthesis is rigidly fixed on the jaw, the final control of the patient's bite is performed. At this stage, the final correction of the position of the lower jaw is possible by changing the longitudinal size of the endoprosthesis in the direction of increase or decrease by turning the head 19 of the screw 12 in the desired direction with a screwdriver (to reduce the longitudinal size, the endoprosthesis head is pre-set to the extension position by 5 mm) .

The next step is suturing the wound. The fabrics are layered in layers and sutured. For 2-3 days, drainage is left in the wound for the outflow of exudate, antibacterial and decongestant therapy are prescribed. In the first days after surgery, the patient is prescribed mechanotherapy (a gradual increase in mouth opening).

After completing the course of anti-inflammatory therapy and removing the stitches, the patient is discharged for outpatient monitoring, during which the parameters of the growth of bone tissue of the facial skull of the patient and the parameters of occlusion are monitored.

As the bones of the patient’s face grow on the healthy side of the lower jaw, an increase in the vertical size of the branch occurs, which does not occur on the operated side, given the presence of an endoprosthesis and the absence of a conditional bone growth zone. In the absence of correction of the above changes, secondary deformation of the lower jaw in the form of bone tissue hypertrophy on the healthy side and underdevelopment on the side of the operation inevitably occur. The consequence of this is a violation of the bite, chewing function, which leads to dysplastic processes in the temporomandibular joint on the healthy side.

In the case of the operation described above using any of the prototypes of our invention to prevent secondary deformation of the bones of the face, it is necessary to replace the entire endoprosthesis with a similar, but larger one, or use another technique for replacing a bone defect. In any case, this requires repeated surgical intervention in the maxillofacial region in an amount equivalent to the first stage of treatment, and is difficult to tolerate by the patient. Such operations are more difficult due to the fact that soft tissues undergo cicatricial changes, resulting in impaired blood supply and trophism. This leads to an increase in the number of postoperative complications, such as inflammatory processes, implant rejection, etc.

In the case of an operation using our invention, it is possible to compensate for the growth of bone tissue of the lower jaw branch on the healthy side by increasing the longitudinal size of the endoprosthesis on the side of the operation without replacing it and without resorting to volumetric surgery in a hospital.

Namely, it measures and compares the distance from the angle of the lower jaw to the head of the condylar process on the healthy side and the distance from the angle of the lower jaw to the head of the endoprosthesis on the side of the operation (for this, the patient is recommended to make a stereolithographic model of the lower jaw, which allows to measure these sizes with an accuracy of 1 mm).

Then, on an outpatient basis, under local anesthesia with a sharp scalpel, a skin incision is made with a length of not more than 0.5 cm in the projection of the head of the endoprosthesis adjustment screw, which is previously determined by palpation and marked. Stupidly and acutely soft tissues are dissected tunnelwise to the head 19 of the screw 12 of the endoprosthesis, a screwdriver is inserted into the surgical wound, which is attached to the head 19 of the screw 12. After that, the latter turns in the desired direction by a predetermined number of revolutions, the number of which determines the magnitude of the increase in the longitudinal size of the endoprosthesis (this the value is determined by the thread pitch of the adjusting screw). At the final stage, a suture is made on the skin and an aseptic dressing is applied, after which the patient can be at home and immediately begin to work or study.

As the patient grows further, if necessary, the above manipulation can be repeated, also during orthodontic treatment in the postoperative period, if necessary, correction of the height of the endoprosthesis in the opposite direction (in the direction of decrease) is possible.

Clinical example

Patient S., born 1988 I went to the MONIKA Maxillofacial Surgery Clinic with complaints about limiting the opening of the mouth to 0.8 cm, difficulty chewing food, deformation of the middle and lower zones of the face, limiting lateral movements of the lower jaw.

From the anamnesis: 08/18/96 received a severe combined injury when falling from a height of the 5th floor. Delivered by an SMP machine to the Central City Hospital Elektrostal with a diagnosis of severe head injury, fracture of the cranial vault with transition to the base of the skull, contusion of the brain, fracture of the lower and alveolar process of the upper jaw, laceration of the chin, blunt trauma to the chest and abdomen , fracture of the femur, traumatic shock of the I-II degree.

After undergoing treatment in a hospital for several years, he periodically consulted a doctor with complaints of difficulty opening his mouth, changes in face configuration and mastication of chewing function, which intensified over time. Not once consulted by an orthodontist. The patient was given recommendations for developing mouth openings, taking into account the clinical picture of the disease at the time of treatment, which were performed irregularly and incompletely, and therefore conservative treatment did not bring a positive effect.

During the patient’s last visit, the maximum opening of the mouth was limited to 0.8 cm; there was a deformation of the lower jaw due to hypertrophy of its right half and underdevelopment of the left. In the area of the left TMJ, a conglomerate of tissues of dense consistency with no signs of movement in the joint was determined. In the area of the right TMJ, the head of the condylar process, with little mobility, was determined. On the basis of clinical and radiological data, the diagnosis was made: bone ankylosis of the left and fibrous ankylosis of the right TMJ, which developed against the background of post-traumatic hemarthrosis, deformation of the facial skeleton. A treatment plan has been drawn up.

1. To develop and create an endoprosthesis corresponding to the individual characteristics of the patient, it is necessary to make a stereolithographic model of the patient’s skull based on the data of spiral computed tomography in 3D projection.

2. On the obtained skull model, to simulate the operation and make an individual endoprosthesis of the condylar process and articular fossa.

3. Prepare an orthodontic treatment plan to correct the occlusal relationship in the postoperative period.

4. Conduct a complete preoperative clinical and laboratory examination of the patient.

Endoprosthetics of the left TMJ was carried out using the present invention with an individually prepared endoprosthesis of the condylar process and articular fossa according to the method described above.

Received positive results. Significantly increased mouth opening. There is a range of movements of the lower jaw in the area of the prosthetic joint, as well as on the opposite side, allowing the patient to fully eat, and also giving the opportunity to carry out orthodontic treatment aimed at correcting the occlusion. Deformation of the middle and lower zones of the face, and with it cosmetic defects, decreased.

EFFECT: invention makes it possible to compensate for the growth of bone tissue of the lower jaw branch on the healthy side by increasing the longitudinal size of the endoprosthesis on the operation side without replacing it and without resorting to volumetric surgery in a hospital, thereby minimizing secondary deformation of the facial skeleton without resorting to traumatic surgery in full, which is especially important for children and young patients.

In addition to the above variants of the invention, numerous other modifications are possible.

All of them are covered by the following claims.

Claims (10)

1. Device for replacing the condylar process of the lower jaw, including a block-shaped body, a body for interacting with the articular fossa, having a protrusion for installation in the articular fossa, at least a pair of means for securing the block-shaped body to the lower jaw and means for moving and fixing the body for interaction with the surface of the articular fossa relative to the block-shaped body, and the body for interaction with the surface of the articular fossa is designed as a separate unit and mounted with the possibility of longitudinal movement relative to the block-shaped body, characterized in that the means of moving and fixing the body for interacting with the articular fossa relative to the block-shaped body contains a rod-shaped element mounted with the possibility of longitudinal movement in a longitudinal hole made in the block-shaped body, and there is a hole in the rod-shaped element which contains a screw connected to it by a threaded connection, provided with means for fixing the position of the screw relative to the block-like body without the possibility of longitudinal movement, and on the opposite side on the rod-shaped element there is a body for interaction with the articular fossa, while there is the possibility of access to the screw head of the rotary drive tool by percutaneous puncture. 2. The device according to claim 1, characterized in that the rod-shaped element and the longitudinal hole in the block-shaped body in which it is mounted are made flattened. 3. The device according to claim 1, characterized in that the said screw is made with an annular groove, and the means for fixing the position of the screw relative to the block-like body without the possibility of longitudinal movement contains an element that is mounted in one part in the block-shaped body, and the other part is placed in the ring groove of the screw . 4. The device according to claim 3, characterized in that the element, which is mounted in one part in a block-like body, and the other part is placed in the annular groove of the screw, is a key. 5. The device according to claim 4, characterized in that the said key is made of a U-shaped. 6. The device according to claim 1, characterized in that it is additionally equipped with a means for limiting the longitudinal movement of the body to interact with the articular fossa relative to the block-shaped body. 7. The device according to claim 6, characterized in that the means for limiting the longitudinal movement of the body to interact with the articular fossa relative to the block-shaped body contains an element which is fixedly connected to the block-shaped body by one part and the rod-shaped element is longitudinally recessed, wherein the recess does not reach at least one of the ends of the rod-shaped element. 8. The device according to claim 7, characterized in that the element, which is fixedly connected to the block-shaped body by one part and placed in the longitudinal recess of the rod-shaped element by one part, is a pin. 9. The device according to claim 1, characterized in that the block-shaped body is made with a through hole, each means for securing the block-like body to be attached to the lower jaw contains a screw, the rod of which is placed in the through hole of the block-shaped body, and the cap covers the surface of the block-shaped body. 10. The device according to claim 9, characterized in that at least one of the through holes of the block-shaped body is made of elongated shape.

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