RU2762318C1 - Method and device for reconstruction of the lower jaw - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to oncology, maxillofacial, plastic surgery, and can be used when performing resection of the lower jaw with restoration of the temporomandibular joint. The bone margins of the defect are prepared in the area of ​​the zygomatic and temporal bones. After contact of all attachment points of the endoprosthesis with the bony edges of the zygomatic and temporal bones, holes are formed in the bone tissue for screwing in titanium mini-screws with a diameter of 2.0 mm. The peroneal flap is simulated to fit. templates are used, which are created on the basis of computed tomography data of the lower extremities. The templates are fixed on the anterior surface of the bone fragment. Bone blocks are formed. Bone fragments on the vascular pedicle are placed and fixed in the bed of the jaw component of the endoprosthesis. The jaw component is transferred to the defect area and the two-component endoprosthesis is assembled. The articular head of the mandible frame is inserted into the capsule of the articular part of the endoprosthesis in the area of ​​the zygomatic arch. Reconstruction of the temporomandibular joint is performed. The distal end of the articular component is fixed to the surface using mini-screws with a diameter of 2 mm and a length of 5.5 mm, also to the temporal bone through holes with a diameter of 2.05 mm in the supporting surface of the articular element of the endoprosthesis. The frame of the lower jaw with the bone blocks of the peroneal flap fixed in it is fixed in the area of ​​the sawdust of the lower jaw. The vascular pedicle of the peroneal flap is brought out into the upper third of the neck and microvascular anastomoses are applied to the facial vessels. A device for endoprosthetics of the lower jaw in the form of an L-shaped frame, repeating the outlines of the patient's healthy jaw, was made using 3D printing from Ti64ELI titanium alloy metal powder according to models obtained from computed tomography data. The jaw component replaces the resected part of the lower jaw from the head to the area of ​​resection, includes an attachment area to the unresected part of the lower jaw bone, a bed for placing a bone graft, and a leg with an articular head. The stock forms a J-shaped cross-sectional profile made in the form of a 1.1 mm thick mesh plate formed by rhombic holes 2 - 1.2 mm in size and 0.5 mm wide bridges. Around the perimeter of the plate, an edging with a height of 2.5 to 4 mm is made for attaching the frame to the jaw and bone blocks of the graft to the frame. In the mesh formed by the holes, supporting elements with a diameter of 4 mm and a hole in the center with a diameter of 2.05 mm are made. Bone blocks from the patient's fibula are located in the jaw component in this way: two of them are oriented along the body of the mandible and one along the branch of the reconstructed mandible. The attachment area has a J-shaped profile and wraps around the anterior and lower parts of the lower jaw in the area of ​​its sawdust. The leg, replacing the upper part of the branch of the lower jaw with the condylar process, is a beam made in the form of a body of revolution, expanding towards the base and tapering closer to the articular head, ending with an articular head in the form of an ellipsoid. At the junction of the bed with the leg, an end stop is made for attaching the bone block of the graft located in the region of the branch of the lower jaw. Its profile repeats the profile of the end of the graft abutting against it. On the surface of the stop there is a mesh structure with pore sizes from 0.3 to 1 mm. The articular element consists of an articular capsule and a support base. The capsule is a parallelepiped with rounded side edges. A cavity is made from the lower end of the capsule, into which the articular head of the jaw component is placed. The hole and cavity shapes are chosen so that after the articular head is inserted into it, its movement is ensured. A dovetail seat is made from the upper end of the capsule for connection to the base, containing holes for holding fastening screws. The support base is a rectangular body with a thickness of 4 to 14 mm with rounded edges, passing into an L-shaped spatial frame, and a support surface on the base of the skull support surface. To attach the component to the base of the skull using mini-screws with a diameter of 2 mm and a length of 5.5 mm, holes with a diameter of 2.05 mm are made at the base of the supporting surface. The supporting surface of the base on the skull bone is made according to the model obtained from the computed tomography data, repeats the contours of the bone in the place of their conjugation. The component of the zygomatic arch has the shape of a bone, one end is oriented to the supporting surface of the base, and the other is placed on the temporal process of the zygomatic bone, in section it has an O-shape. The surfaces of the endoprosthesis adjacent to the bones are made in the form of a mesh structure with pores from 0.3 to 1 mm.

EFFECT: method provides for the restoration of the functions of the temporomandibular joint and a reduction in the number of postoperative complications associated with the development of inflammatory processes and the dislocation of reconstructive material due to the use of a two-component endoprosthesis.

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Description

The invention relates to medicine and can be used in oncology, maxillofacial, plastic surgery when performing resection of the lower jaw with restoration of the temporomandibular joint.

In the Russian Federation, there is a steady increase in the incidence of oral cancer. In the period from 2008 to 2018. the increase in the incidence of oral cancer was 28.9% for men and 56.23% for women [A.D. Kaprin, V.V. Starinsky, G.V. Petrova, 2019]. Combined treatment of tumors of the oral cavity is preferred, where surgical treatment is given a dominant role. Removal of tumors of the oral cavity with segmental resection of the lower jaw is the most difficult and responsible step in the surgical treatment of this category of patients. The elimination of the arising defects of the lower jaw is an even more difficult problem in terms of obtaining optimal functional and aesthetic results. Most often, one has to deal with the restoration of the lower jaw after its segmental resections. Achieving good functional and cosmetic results depends on the correct choice of reconstruction technique.

The main goal of the reconstruction of the lower jaw is to restore its continuity, the symmetry of the lower face zone, to create favorable conditions for dentoalveolar prosthetics and swallowing. Therefore, all reconstructive techniques used must meet these requirements. An essential distinguishing feature of the lower jaw, from other bone structures of the maxillofacial region, is its mobility in the area of the temporomandibular joints. Also, the result of reconstruction should be maintained for a long time without the development of signs of inflammation and dislocation of the used reconstructive material.

The use of free revascularized bone grafts with high biocompatibility and minimal risk of infection is considered the standard of modern reconstructive plastic surgery of the maxillofacial area. This method has proven itself on the positive side, allows in most cases to perform adequate compensation for defects in the maxillofacial region and is widely used in foreign and domestic clinics. However, the key disadvantage of this approach is the limitation in the collection of bone grafts for extended defects and the difficulty of modeling the bone graft to achieve acceptable cosmetic and functional results.

Known techniques for the restoration of the lower jaw and temporomandibular joint using various bone autografts (tissue flaps of the patient) and artificial materials. The limited use of these flaps in reconstructive surgery of the oral cavity is due to their shortcomings: insufficient reconstructive material in the elimination of extensive defects in bone structures, unsatisfactory functional results in the restoration of the temporomandibular joint, inconsistency of the reconstructive material and the area of reconstruction in shape and design.

A known method of reconstruction of the lower jaw with an allogeneic graft with one-stage dental implantation (RU 2595087 C1 from 20.08.2016). The method consists in resection of the defective bone segment of the lower jaw, followed by its replacement with a graft, in which dental implants are installed at the same time. An allogenic bone graft from the Alloplant series is used as a graft. The graft with dental implants is fixed to its own jaw with mini-screws and the junction between the graft and the jaw is wrapped with an allogenic membrane from the dura mater of the Alloplant series.

их высоты в вертикальной плоскости; промежуточная часть пластины имеет 2 отверстия для фиксации к костной ткани реконструктивного аутотрансплантата, которые расположены на одном уровне друг с другом; промежуточная часть пластины соединена с проксимальным и дистальным концами пластины при помощи переходных плеч под углом 45 градусов.A reconstructive plate of the lower jaw was also developed (RU 194058 U1 dated 11/26/2019), which has holes for fixation to the lower jaw with screws, the proximal and distal parts of the plate are fixed to the lower jaw from the vestibular side, while the intermediate part of the plate is located above the proximal and distal parts plates on

their heights in the vertical plane; the intermediate part of the plate has 2 holes for fixing the reconstructive autograft to the bone tissue, which are located at the same level with each other; the intermediate part of the plate is connected to the proximal and distal ends of the plate by means of transition arms at an angle of 45 degrees.

There is a known method of reconstruction of the lower jaw (RU 2665147 C1 from 28.08.2018) in which malignant tumors of the lower jaw are removed and reconstructed with a graft using microsurgical techniques. A muscle flap is formed from the pectoralis major muscle. A surgical pocket is created from the lateral edge of the muscle, into which the endoprosthesis is placed with the articular head up to the projection of the angle of the lower jaw with a turn and its advancement in the thickness of the muscle by 110 degrees. Spatial three-dimensional reconstruction of the lower jaw, the floor of the oral cavity and facial tissues is carried out by means of geometric modulation of the tissues of the displaced flap and graft. Further, the material for the endoprosthesis is moved from the branch to the body to the area of the defect, taking into account the restoration of the anatomical and functional features of the lower jaw. On one side, the endoprosthesis is placed in the area of the articular surface of the temporomandibular joint, on the other side - to the residual fragment of the lower jaw to the osteotomy line in a single complex with the pectoralis major muscle, fixed with a bone suture, followed by the imposition of blind sutures on the muscle fibers.

A known method for the reconstruction of a defect in the lower jaw using an endoprosthesis (RU 2714212 C1 from 13.02.2020). The method consists in manufacturing an endoprosthesis from titanium and its alloy in the form of a three-dimensional porous body, repeating the geometry of the reconstructed defect. Resection of the lower jaw is performed with disarticulation of the temporomandibular joint. Then an incision is made in the projection of the pectoralis major muscle, the flap of which is separated and taken to the side. A surgical pocket is created in the muscle flap across the course of its fibers, into which the endoprosthesis is placed and installed after moving in the muscle flap and turning on the one hand into the area of the articular surface of the temporomandibular joint, and on the other hand, along the osteotomy line with a residual fragment of the lower jaw with fixation with a bone suture. The method insufficiently provides a one-step restoration of the anatomical and aesthetic relationships of the facial contours, the possibility of reconstruction in conditions of a lack of soft tissues to cover the endoprosthesis, maintaining the chewing function of the lower jaw in full, shortening the treatment time and shortening the period of postoperative rehabilitation. This is due to the design of the endoprosthesis used, which has certain limitations in ensuring the mobility of the lower jaw in the area of the temporomandibular joints, which can lead to the development of signs of inflammation and dislocation of the used reconstructive material.

The new technical result is a more adequate restoration of the functions of the temporomandibular joint due to the use of a two-component endoprosthesis, a reduction in the number of postoperative complications associated with the development of inflammatory processes and the dislocation of reconstructive material.

To achieve a new technical result in the method of reconstruction of the lower jaw, including the manufacture of an endoprosthesis from a titanium alloy in the form of a three-dimensional body, repeating the geometry of the reconstructed defect, resection of the lower jaw with disarticulation of the temporomandibular joint, placement of the endoprosthesis in the defect zone with its subsequent fixation and wound closure, replacement of the defect is carried out using an individual two-component endoprosthesis according to claim 2, including the jaw and articular elements, preparation of the bone edges of the defect in the area of the zygomatic and temporal bones: by milling the bone edges of the wound, removal of soft tissues around the bone edges and alignment of the bone edge of the defect to which the endoprosthesis will be attached, after contact of all attachment points of the endoprosthesis with the bony edges of the zygomatic and temporal bones, using an operating drill and a drill with a diameter of 2.05 mm, they form holes in the bone tissue for screwing in titanium miniscrews di ameter of 2.0 mm, then, after fixing the articular part of the endoprosthesis using titanium to the bone margins of the defect, the fixation is monitored for the absence of flotation of the endoprosthesis under load, after which the peroneal flap is isolated and modeled according to the size and design of the restored area of the lower jaw, when In this case, individual plastic resection templates are used, which are created on the basis of computed tomography data of the patient's lower extremities, taking into account a specific reconstructive task, these templates are temporarily fixed on the anterior surface of the bone fragment, after which, with the help of surgical saws, the formation of bone blocks is performed with a given, according to computer planning the length and characteristics of the surfaces in contact with each other, after which, the formed bone fragments on the vascular pedicle are sequentially placed and fixed in the bed of the jaw component of the endoprosthesis, the jaw component is transferred to the area and the defect on the face and the final assembly of the two-component endoprosthesis, as well as the articular head of the mandible frame is inserted into the capsule of the articular part of the endoprosthesis in the area of the zygomatic arch, performing the reconstruction of the temporomandibular joint, by replacing the lost zygomatic arch with the articular element of the device according to claim 2, while fixing the distal end of the articular component to the surface using self-tapping miniscrews with a diameter of 2 mm and a length of 5.5 mm, also to the temporal bone through holes with a diameter of 2.05 mm in the supporting surface of the articular element of the endoprosthesis, after which, the frame of the lower jaw, with the bone blocks of the fibular The flap, with the help of titanium miniscrews, is fixed in the area of the lower jaw sawdust, the vascular pedicle of the peroneal flap is brought out into the area of the upper third of the neck and microvascular anastomoses are applied with the facial vessels.

Also, to achieve a new technical result, a device for endoprosthetics of the lower jaw, which is an individual two-component endoprosthesis made in the form of an L-shaped spatial frame, repeating the outlines of the patient's healthy jaw, is made using three-dimensional printing from metal powder of titanium alloy Ti64ELI according to models obtained from computed tomography data of the patient's facial skeleton, also consists of two parts - the jaw component and the articular element, while the jaw component replaces the resected part of the lower jaw from the head to the resection area, includes three sections: an attachment area to the non-resected part of the lower jaw bone, a bed for placement bone graft and a leg with an articular head, while the bed forms a J-shaped profile in section, made in the form of a mesh plate with a thickness of 1.1 mm formed by rhombic holes measuring 2x1.2 mm and bridges 0.5 mm wide , also, along the perimeter of the plate, an edging is made with a height of 2.5 to 4 mm, for attaching the frame to the jaw and bone blocks of the graft to the frame, supporting elements with a diameter of 4 mm and a hole in the center with a diameter of 2.05 mm are made in the mesh formed by the holes, and bone blocks made of the patient's fibula are located in the jaw component in this way: two of them are oriented along the body of the lower jaw and one along the branch of the reconstructed lower jaw, also, the attachment area has a J-shaped profile in cross section and covers the anterior and lower parts of the lower jaw in the area of its sawdust, while the leg replacing the upper part of the branch of the lower jaw with the condylar process, represents a beam made in the form of a body of revolution, expanding towards the base and tapering closer to the articular head, the leg also ends with a polished articular head made in the form of an ellipsoid, and in place the connection of the bed for the placement of the bone graft with the stem is made with an end a stop for attaching the bone block of the graft located in the region of the branch of the lower jaw, while the profile of the end stop body repeats the profile of the end of the graft abutting against it, a mesh structure is made on the surface of the stop with pore sizes from 0.3 to 1 mm, the articular element consists of two parts - articular capsule and support base with a zygomatic component, the articular capsule is a parallelepiped with rounded lateral edges, while an internal cavity is made from the lower end, into which the articular head of the jaw component is placed, and the shape of the hole and cavity is chosen so that after insertion into of the articular head, its movement was ensured, a dovetail seat was made from the upper end of the capsule for connection with the base, contains holes for holding fastening screws, while the support base is a rectangular body, with a thickness of 4 to 14 mm with rounded edges passing into space an L-shaped frame that replaces the missing zygomatic arch, and a support surface on the base of the skull support surface, for attaching the component to the skull base using miniscrews with a diameter of 2 mm and a length of 5.5 mm, holes with a diameter of 2.05 mm are made at the base of the support surface, the supporting surface of the base on the skull bone is made according to the anatomical model obtained from the computed tomography of the patient, and repeats the contours of the bone at the point of their conjugation, the component of the zygomatic arch has a shape close to the anatomical shape of the patient's bone, one end is oriented to the supporting surface of the base, and the other - placed on the temporal process of the zygomatic bone, in section it has an O-shape, while the surfaces of the endoprosthesis adjacent to the bones are made in the form of a mesh structure with pore sizes from 0.3 to 1 mm. " Joint capsule manufacturing technology - milling from UHMWPE material. Base manufacturing technology - 3D printing from Ti64ELI titanium alloy metal powder.

In Figs 1-3 depicts a device for arthroplasty of the lower jaw. The device represents an individual two-component endoprosthesis, the body of which is made in the form of an L-shaped spatial frame 1, repeating the outlines of the patient's healthy jaw according to the models obtained from the computed tomography data of the patient's facial skeleton, while the device is made using three-dimensional printing from metal powder of titanium alloy Ti64ELI , consists of two parts - jaw component 2 and articular element 3, jaw component 2 replaces the resected part of the lower jaw from the head to the resection area (usually the chin area), frame 1 includes three sections: section 4 of attachment to the unresected part of the lower jaw bone, bed 5 for placement of a bone graft 6 and a leg 7 with an articular head 8, while the bed 5 forms a J-shaped profile in section, made in the form of a profiled plate with a thickness of 1.1 mm formed by holes 9 of a rhombic shape measuring 2 × 1.2 mm and a jumper 0.5 mm wide, also, along the perimeter of the square Astyna 1, the edging is made with a height of 2.5 to 4 mm, also for attaching the frame 1 to the jaw and bone blocks of the graft 6 to the frame, in the mesh formed by holes 9, supporting elements 10 with a diameter of 4 mm and a hole in the center with a diameter of 2.05 mm are made, fastening is carried out through these holes using self-tapping miniscrews with a diameter of 2 mm and a length of 5.5 mm, the frame 1 is designed with the possibility of placing in it bone blocks of the graft 6 made of bone blocks of the fibula of the same patient, located two along the body of the lower jaw and one along branches of the reconstructed lower jaw. The shape, size and location of the grafts are planned at the design stage of the product according to the computed tomography of the patient's lower extremities, and are selected in such a way as to restore the shape of the lost bone as much as possible. For this, individual plastic resection templates are created for the bone fragment of the fibula.

The attachment area is similar in design to the bed, has a J-shaped cross-sectional profile and tightly wraps around the anterior and lower part of the lower jaw in the sawdust area (usually the chin area). Fastening of the frame 1 to the lower jaw is carried out similarly to the fastening of the graft with self-tapping miniscrews through the holes 9 in the frame.

The stem 7 replaces the upper part of the branch of the lower jaw with the condylar process, and is a beam in the form of a body of revolution expanding towards the base and tapering closer to the articular head. The leg 7 ends with a polished articular head 8 in the form of an ellipsoid. At the junction of the frame with the leg, an end stop 11 is made for attaching the extreme bone block of the graft. The profile of the end stop 11 body follows the profile of the end of the bone block of the graft abutting against it. On the surface of the stop, a mesh structure 14 is made to increase the osseointegration properties with pore sizes from 0.3 to 1 mm.

The design and modeling of the jaw component, the selection of the graft, the installation technology are carried out in a computer environment according to the models obtained from the data of computed tomography of the patient's facial skeleton. The product is individualized with sufficient accuracy to repeat the anatomical contours of both the lost bone, in order to achieve an aesthetic effect, and the contours of the bones with which the framework is fastened (attachment site) and the geometry of the grafts, achieving maximum adherence of the framework to them.

The articular component consists of two parts - the articular capsule 12 and the support base 13 with the zygomatic frame. The articular capsule 12 is a parallelepiped with rounded lateral edges 14. An internal cavity 15 is made from the lower end, through which the articular head 8 of the jaw component is placed. The shape of the hole and cavity is such that after insertion of the articular head 8 into it, its free movement within the anatomical limits of the jaw is ensured, but at the same time preventing it from falling out. From the upper end of the articular capsule 12, a dovetail-shaped seat 16 is made for connection to the base, as well as holes 17 for holding fastening screws.

The support base is a body 18, rectangular in plan, with a thickness of 4 to 14 mm with edges rounded similar to the profile of the capsule, passing into a spatial frame 19, replacing the missing zygomatic arch and the receiving surface of the temporomandibular joint, next to the auditory canal. On the base, a reciprocal seat is made for fixing the articular capsule 12. To attach the articular component to the base of the skull, self-tapping screws with a diameter of 2 mm and a length of 5.5 mm are used; holes 21 with a diameter of 2.05 mm are also made in the base and the supporting surface. The supporting surface of the base of the articular element of the endoprosthesis is made on the basis of the anatomical model obtained from the computed tomography of the patient, and completely repeats the contours of the bone at the interface, which makes it possible to achieve a sufficiently tight fixation of the articular element. The frame of the zygomatic component (zygomatic arch) has a shape close to the anatomical shape of the patient's bone, while at one end it passes into the supporting surface of the base of the articular element of the endoprosthesis, and with the other it lies on the temporal process of the zygomatic bone. In cross section, it is O-shaped. The rest of the construct is similar to the frame of the lower jaw. On the surfaces adjacent to the bones, a branched mesh structure is made to increase the osseointegration properties with pore sizes from 0.3 to 1 mm.

Joint capsule manufacturing technology - milling from UHMWPE material.

Base manufacturing technology - 3D printing from Ti64ELI titanium alloy metal powder.

Frame manufacturing technology - 3D printing from Ti64ELI titanium alloy metal powder.

The method is carried out as follows.

Two-component reconstructive endoprosthesis for the mandible and temporomandibular joint is created individually for each patient based on the data of spiral computed tomography of the facial skeleton and using additive technologies. This endoprosthesis can be sterilized by the currently known methods for endoprostheses (dry oven, autoclaving, sterilization with ethylene oxide gas) without disturbing its structural and functional properties. After carrying out all the measures aimed at sterilization, the endoprosthesis can be used for the reconstruction of the lower jaw. After resection of the affected bone structures (during the initial reconstruction) or the release of a pre-existing defect of the lower jaw from the scar tissue (in the case of delayed restorative surgical treatment), the reconstructive stage is performed. Adequate access to the bone defect is provided, taking into account the free (without tension of the integumentary tissues) location of the individual endoprosthesis. Preparation of the bone edges of the defect in the area of the zygomatic and temporal bones is performed: removal of soft tissues around the bone edges and alignment of the bone edge of the defect using cutters to which the endoprosthesis will be attached. At this stage, it is important to achieve precise adherence of the contact surfaces of the endoprosthesis to the bone margins of the defect. This condition is achieved by milling the bone edges of the wound. After complete and exact contact of all attachment points of the endoprosthesis with the bony edges of the zygomatic and temporal bones, using an operating drill and a drill with a diameter of 2.05 mm, holes are formed in the bone tissue for screwing in titanium miniscrews with a diameter of 2.0 mm. After complete fixation of the articular element of the endoprosthesis using titanium miniscrews to the bone margins of the defect, the fixation is monitored (no flotation of the implant under load). After that, the peroneal flap is isolated according to the standard technique. At the stage of modeling the bone fragment of the peroneal flap for the size and design of the restored area of the lower jaw, individual plastic resection templates are used, which are created on the basis of computed tomography of the patient's lower extremities, taking into account a specific reconstructive task. These templates are temporarily fixed on the anterior surface of the bone fragment, after which, with the help of surgical saws, bone blocks are formed with a given length and characteristics of the contacting surfaces according to computer planning. After that, the formed bone fragments on the vascular pedicle are sequentially placed and fixed in the second component of the individual reconstructive endoprosthesis, which is the J-shaped frame of the lower jaw. After checking the correct location of the bone blocks in the bed of the lower jaw endoprosthesis frame and subject to their adequate blood supply, the lower jaw frame is transferred to the area of the defect on the face and the final assembly of the two-component individual implant is carried out. The articular head of the mandible frame is inserted into the articular capsule of the articular element of the endoprosthesis. Thus, the reconstruction of the temporomandibular joint is performed. After that, the frame of the lower jaw, with the bone blocks of the peroneal flap fixed in it, is fixed in the area of the sawdust of the lower jaw (usually the chin area) using titanium minivits. The vascular pedicle of the peroneal flap is brought out into the upper third of the neck and microvascular anastomoses (usually with facial vessels) are applied to restore blood flow in the bone blocks.

Thus, the proposed method uses an endoprosthesis individually created for each clinical case, which accurately repeats the lost bone structures of the patient, is able to adequately restore extended defects of the lower jaw and zygomatic bone, with the reconstruction of the temporomandibular joint. Also, the developed method involves the use of a free revascularized bone flap (peroneal flap) in order to improve reconstructive and cosmetic results.

The positive results of these operations, the technical readiness of the method for transfer to widespread use testify to the compliance of the proposal with the criterion of the invention "industrial applicability".

The achievability of the technical result is confirmed by clinical examples of the application of the method in the reconstructive treatment of patients with tumors of the tongue and the floor of the oral cavity in the department of head and neck tumors of the Research Institute of Oncology of the Tomsk National Research Medical Center

Example 1

Patient I., 59 years old. Diagnosis: Cancer of the mucous membrane of the alveolar process of the upper jaw T3N0M0. It is known from the anamnesis that cancer of the alveolar process of the upper jaw was verified in December 2017. In the conditions of the Research Institute of Oncology of the Tomsk Research and Development Center, he received a combination treatment: radiation therapy in SDS 40 Gy + resection of the upper jaw on the left and lymphadenectomy of the neck on the left. Then, in the conditions of the Department of Maxillofacial Surgery of the Regional Clinical Hospital of Tomsk, surgical treatment was performed for contracture of the lower jaw (02.11.2018). Dynamic observation revealed osteomyelitis of the lower jaw on the right. The lower jaw was resected on the left with reconstruction with a titanium plate (07.2019). In August 2019, a dystopia of the reconstructive plate with the development of soft tissue inflammation in the area of reconstruction was revealed. In the conditions of the Department of Maxillofacial Surgery of the Tomsk Regional Clinical Hospital, the removal of the reconstructive plate of the lower jaw was performed (11/21/2019). The patient applied to the Oncology Research Institute of the Tomsk National Research Medical Center in April 2020 for reconstructive plastic treatment. On examination, a pronounced deformation of the left half of the face due to postoperative scars and the absence of bone structures of the lower and upper jaw attracted attention. According to the performed computed tomography of the facial skeleton, the defect of the lower jaw was determined from tooth 33 to the region of the temporomandibular joint on the left, with the absence of the latter. The absence of the temporal process of the zygomatic bone (upper temporomandibular joint) was also noted.

Taking into account the complexity and vastness of the forthcoming reconstructive operations, it was decided to manufacture an individual reconstructive endoprosthesis for the body and ramus of the mandible, as well as for the zygomatic bone and the temporomandibular joint. A combination of this reconstructive endoprosthesis with a free bone flap was also planned.

The design and modeling of the endoprosthesis, the modeling of the bone blocks of the autograft, and the planning of the installation technology were carried out in a computer environment according to the models obtained from the computed tomography data of the patient's facial skeleton and the fibula. The product is individual, with sufficient accuracy it repeats the anatomical contours of both the lost bone, in order to achieve an aesthetic effect, and the contours of the bones with which the framework is fastened (attachment site) and the geometry of the grafts, achieving maximum adherence of the framework to them.

On June 18, 2020, a delayed microsurgical reconstruction of the lower jaw was performed using an individual endoprosthesis in accordance with clause 2 of the claims with arthroplasty of the mandibular joint in the planned volume. Access was made to the sawdust of the lower jaw in the chin area. The sawdust of the lower jaw was isolated from the scars and rotated to the correct position (to the central line). Access to the left zygomatic bone sawdust was made. The separation of the branches of the facial nerve from the scar tissue and tissue of the parotid salivary gland was carried out. Access to the temporal bone, upper jaw on the left. Prepared (removed all scar tissue) bone margins around the bone margins of the zygomatic bone sawdust. In the area of the defect of the zygomatic bone and the temporomandibular joint, the upper ("articular") part of an individual endoprosthesis made of titanium was installed for the reconstruction of the lower jaw with an articular cavity made of high-density polypropylene. This fragment of an individual endoprosthesis, with the help of 8 miniscrews, is fixed to the sawdust of the zygomatic bone in the region of the upper jaw and temporal bone, as well as to the temporal bone itself. In the submandibular region on the left, the facial vessels are highlighted and prepared for the imposition of microvascular anastomoses. Control of hemostasis. Performed a collection of the musculocutaneous peroneal flap on the left. The bone fragment was modeled along the length and shape of the defect in the alveolar process of the lower jaw using an individual template for bone blocks. The angles and designs of the three bone blocks have been modeled. These bone blocks are fixed in the bed of an individual titanium endoprosthesis of the lower jaw with an articular head. The individual endoprosthesis of the lower jaw, together with the bone blocks, was moved to the area of reconstruction, the articular head was inserted into the capsule of the articular element of the endoprosthesis in the area of the zygomatic arch. Also, the endoprosthesis was fixed to the sawdust of the lower jaw in the chin area using minivits. The vascular pedicle of the flap is brought into the region of the upper third of the neck on the left to the region of the facial vessels. The imposition of 3 microvascular anastomosis with the facial vessels was performed: one arterial and two venous (branches of the facial vein). Suture material - Prolen 9-0. Control of the patency of vascular anastomoses. Control of blood flow in all fragments of the flap. Control of hemostasis. Layer-by-layer suturing of the neck wound, leaving active drainage in the left parotid region.

This clinical example shows the possibility of eliminating an extended and complex defect of the lower jaw and zygomatic bone with restoration of the temporomandibular joint. Also, a feature of this case is that a successfully performed reconstructive operation was performed in unfavorable conditions - the consequences of previous radiation therapy and repeated surgical treatment. The used individual reconstructive endoprosthesis in combination with a bone flap allowed the bone structures of the maxillofacial region to be fully and as accurately as possible, with the creation of favorable conditions for restoring the functional activity of the oral cavity (chewing, dental prosthetics).

Appendix

FIG. 1. Individual reconstructive endoprosthesis of the lower jaw and temporomandibular joint. 1-3 - bone blocks of the peroneal flap

FIG. 2 a, b. Individual reconstructive endoprosthesis of the lower jaw and temporomandibular joint with fixation points to the area of the lower jaw, temporal and zygomatic bones, as well as fixation of the bone blocks of the peroneal flap.

FIG. 3. Individual reconstructive endoprosthesis of the lower jaw and temporomandibular joint with the area of fixation of the articular capsule to the base of the articular element.

Claims (2)

1. A method for the reconstruction of the lower jaw, including the manufacture of an endoprosthesis from a titanium alloy in the form of a three-dimensional body, repeating the geometry of the reconstructed defect, resection of the lower jaw with disarticulation of the temporomandibular joint, placement of the endoprosthesis in the defect zone with its subsequent fixation and wound closure, characterized in that replacement of the defect is carried out using an individual two-component endoprosthesis according to claim 2, including the jaw and articular elements, preparation of the bone edges of the defect in the area of the zygomatic and temporal bones: by milling the bone edges of the wound, removal of soft tissues around the bone edges and alignment of the bone edge of the defect , to which the endoprosthesis will be attached, after contact of all attachment points of the endoprosthesis with the bony edges of the zygomatic and temporal bones using an operating drill and a drill with a diameter of 2.05 mm, they form holes in the bone tissue for screwing in titanium mini-screws with a diameter of 2.0 mm, then after fixation of the articular part of the endoprosthesis using titanium mini-screws to the bone edges of the defect, the fixation is monitored for the absence of flotation of the endoprosthesis under load, after which the peroneal flap is isolated and modeled according to the size and design of the restored area of the lower jaw, while using individual plastic resection templates , which are created on the basis of computed tomography data of the patient's lower extremities, taking into account a specific reconstructive task, these templates are temporarily fixed on the anterior surface of the bone fragment, after which, using surgical saws, bone blocks are formed with a length set according to computer planning and characteristics of the surfaces in contact with each other, after which the formed bone fragments on the vascular pedicle are sequentially placed and fixed in the bed of the jaw component of the endoprosthesis, the jaw component is transferred to the area of the defect on the faces f and the final assembly of the two-component endoprosthesis, as well as the articular head of the lower jaw frame is inserted into the capsule of the articular part of the endoprosthesis in the zygomatic arch region, performing the reconstruction of the temporomandibular joint by replacing the lost zygomatic arch with the articular element of the device according to claim 2, while fixing the distal end of the articular component to the surface using self-tapping mini-screws with a diameter of 2 mm and a length of 5.5 mm, also to the temporal bone through holes with a diameter of 2.05 mm in the supporting surface of the articular element of the endoprosthesis, after which the frame of the lower jaw with fixed bone blocks of the peroneal flap in with the help of titanium mini-screws, they are fixed in the area of the sawdust of the lower jaw, the vascular pedicle of the peroneal flap is brought out into the area of the upper third of the neck and microvascular anastomoses are applied with the facial vessels. 2. A device for endoprosthetics of the lower jaw, which is an individual two-component endoprosthesis made in the form of an L-shaped spatial frame, repeating the outlines of the patient's healthy jaw, characterized in that it is made using three-dimensional printing from Ti64ELI titanium alloy metal powder according to models obtained from computed tomography data of the patient's facial skeleton, also consists of two parts - the jaw component and the articular element, while the jaw component replaces the resected part of the lower jaw from the head to the resection area, includes three sections: an attachment area to the non-resected part of the lower jaw bone, a bed for placement bone graft and a leg with an articular head, while the bed forms a J-shaped profile in section, made in the form of a mesh plate with a thickness of 1.1 mm, formed by rhombic holes measuring 2 × 1.2 mm and bridges with a width of 0.5 mm, also along the perimeter of the plate nen edging with a height of 2.5 to 4 mm, for fastening the frame to the jaw and bone blocks of the graft to the frame in the mesh formed by the holes, supporting elements with a diameter of 4 mm and with a hole in the center with a diameter of 2.05 mm are made, and the bone blocks made of fibular the patient's bones are located in the jaw component in this way: two of them are oriented along the body of the lower jaw and one along the branch of the reconstructed lower jaw; in this case, the leg, replacing the upper part of the branch of the lower jaw with the condylar process, is a beam made in the form of a body of revolution, expanding towards the base and tapering closer to the articular head, the leg also ends with a polished articular head made in the form of an ellipsoid, and at the junction of the bed for placement of a bone graft with a leg, an end stop is made for attachment. located in the region of the branch of the lower jaw of the bone block of the graft, while the profile of the end stop body repeats the profile of the end of the graft abutting against it, a mesh structure is made on the surface of the stop with pore sizes from 0.3 to 1 mm, the articular element consists of two parts - the articular capsule and a support base with a zygomatic component, the articular capsule is a parallelepiped with rounded lateral edges, while an internal cavity is made from the lower end, into which the articular head of the jaw component is placed, and the shape of the hole and the cavity is chosen so that after insertion of the articular head into it, its movement, a dovetail seat is made from the upper end of the capsule for connection to the base, contains holes for holding fastening screws, while the support base is a rectangular body with a thickness of 4 to 14 mm with rounded edges, passing into an L-shaped spatial frame , deputy missing a zygomatic arch, and a support surface on the base of the skull base, for attaching the component to the base of the skull using mini-screws with a diameter of 2 mm and a length of 5.5 mm, holes with a diameter of 2.05 mm are made at the base of the support surface, the base support surface on the skull bone is made according to the anatomical model obtained from the computed tomography of the patient and follows the contours of the bone in the place of their conjugation, the component of the zygomatic arch has a shape close to the anatomical shape of the patient's bone, one end is oriented to the supporting surface of the base, and the other is placed on the temporal process of the zygomatic bone, in section it has an O-shape, while the surfaces of the endoprosthesis adjacent to the bones are made in the form of a mesh structure with pore sizes from 0.3 to 1 mm.

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