RU2610533C1 - Mandible prosthetic implant - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers the medicine, particularly, to the oral and maxillofacial surgery, and may be used for a substitution of major postresection mandible defects. The prosthetic implant for a substitution of the three-dimensional bone defect of the mandible is individually produced of titanium nickelide according to the anatomic and topographical parameters. The prosthetic implant has holes for screws and a channel for allocation of the inferior alveolar neurovascular bundle. The prosthetic implant is performed according to a stereolithographical model in the form of a perforated plate made of titanium nickelide with a thermal and mechanical shape memory effect. The prosthetic implant contains a body of the prosthetic implant, lateral and medial ends with fixation components at them. The body of the prosthetic implant is performed in the form of a container for transplantation material formed outgoing from the upper edge of the perforated plate as a semi-cylinder component, which in its lower part has a perforated leaf bent towards the direction of the perforated plate until touching its lower edge. The channel for allocation of the inferior alveolar neurovascular bundle is located at the level of transition of the semi-cylinder component into the perforated leaf from the external part. In the upper part of the bent along the generator line of the semi-cylinder component, a row of holes with screw threads is located for the mounting of dental implants. On the lateral end of the prosthetic implant, a notch is performed for formation of two branches with the legs at their ends bent at the angle of 45 degrees for the mounting by the coronoid and articular processes of the mandible. At the tip end of the medial end of the prosthetic implant, legs bent at the angle of 45 degrees are located for the mounting by saved bone segments of the mandible. The prosthetic implant provides the conditions for transformation of a transplantation material consisting of bone osteoplastic and osteoregenerating material into the bone tissue allowing restoring the integrity and uniformity of the mandible by means of strong contact and immobilization of the bone transplant with the saved bone segments.

EFFECT: exclusion of migration of transplantation material by means of joining of the leaves of the prosthetic implant body.

2 cl, 9 dwg

Description

The invention relates to medicine, namely to maxillofacial surgery, and can be used to replace extensive post-resection defects of the lower jaw.

The goal of endoprosthetics is to ensure continuity and accuracy of restoration of resected areas of the lower jaw, reliable stabilization, creation of conditions for bone formation, long-term functioning of the endoprosthesis, preservation of chewing and speech function.

A known lower jaw implant made on the basis of the lower jaw model in the form of an elongated body with transverse through holes for screws to attach the endoprosthesis to the lower jaw bone and widening protruding inward with screw threads for subsequent implant placement. An endoprosthesis is used in combination with a bone graft (patent for utility model RU 146000 U1, IPC A61B 117/58, published September 27, 2014).

The disadvantages of the known endoprosthesis are:

1. Fixation of the endoprosthesis with screws to intact bone fragments is not reliable due to the functional mobility of the lower jaw in different directions. Possible migration of screws from the cancellous bone of the lower jaw with destabilization of the endoprosthesis.

2. The muscles attached to the body of the lower jaw are sutured with suture material through the transverse openings of the endoprosthesis. The conditions for the formation of a reliable connection of the muscle complex with a metal endoprosthesis in the form of a plate are absent.

3. The implementation of the endoprosthesis in the form of a lamellar body does not allow to restore the volume of the lower jaw, and also excludes the protection of the mandibular nerve after its isolation and transposition.

4. The distal end of the endoprosthesis is made in the form of a single branch, which makes it difficult to position and suture the muscles attached to the superior process in the anatomically correct position, which provokes the appearance of cicatricial retraction of soft tissues.

5. The lamellar body of the endoprosthesis does not contain elements for fixing muscles attached to the branches and body of the lower jaw, which reduces the functional qualities of the endoprosthesis.

A device for eliminating defects and deformations of the bone of the lower jaw, including an elongated body with through transverse holes, reinforcing the perforated element in the form of a mesh groove, open downward made integral with the elongated body. The length of the perforated (mesh) element depends on the size of the filled defect. The gutter is filled with bone and osteoplastic material (patent for invention RU 2387410 C1, MKI A61F 2/28, published on 04/27/2010).

The disadvantages of the known device are:

1. The absence of an element to compensate for the defect of the anterior branch and coronoid process of the lower jaw, the inability to fix the cut off temporal, buccal part of the masticatory muscles in the anatomically correct position.

2. To hold the bone osteoplastic material in the mesh grooved element open downward, additional fixation is required.

3. The difficulty of adapting the ends of the device when fixing with screws and wire seams.

4. Dynamic instability of the device due to the resorption of bone tissue around the screws and wire sutures that fix the device to the bone fragments of the lower jaw remaining after the resection.

5. The device does not provide an element for the transposition and preservation of the lower alveolar neurovascular bundle.

Closest to the claimed endoprosthesis is the lower jaw prosthesis (RU 2491899 C1, IPC A61F2 / 28, publication 05/04/2012), made in accordance with the stereolithographic model in the form of a monolithic hollow block of titanium nickelide, including a body with two perforated screw holders, angle and branches of the jaw with a condylar process of spherical shape, coronoid process with a clamp for tendon of the temporal muscle with a groove depth of 3.0 mm on the outer surface of the body and branches of the jaw to accommodate the lower alveolar vascular ervnogo beam.

The disadvantages of the known endoprosthesis of the lower jaw are:

1. The absence of holes in the monolithic hollow part of the endoprosthesis for suturing the muscles attached to the body, corner, branch of the lower jaw, which makes it difficult to restore the motor function of the lower jaw.

2. There are no conditions for using the osteoplastic compound of the material for the formation of bone tissue and with preserved bone fragments to create continuity of the lower jaw.

3. The connection of the endoprosthesis with a safe bone is carried out using perforated fixators in the form of two plates attached to the endoprosthesis and a bone fragment with two screws is not stable, does not provide sufficient strength of the joint, during the functional loads, the endoprosthesis can be disconnected from the bone.

4. The connection of the articular head by means of a perforated plate fastened with screws to the hollow monolithic condylar process during cyclic functional movements of the lower jaw is unreliable.

5. The method of sequentially fastening the ends of the endoprosthesis in the form of perforated plates to the preserved areas of the lower jaw with screws can make it difficult to position the endoprosthesis.

The objective of the invention is to increase the stabilization of the endoprosthesis, the restoration of the continuity of the lower jaw and the transposition of soft tissue elements in the anatomically correct position.

The task is achieved by the lower jaw endoprosthesis to replace the volumetric bone defect of the lower jaw, made individually by anatomical and topographic indices of titanium nickelide, with screw holes, with a groove for placement of the lower alveolar neurovascular bundle. The endoprosthesis is made according to the stereolithographic model in the form of a perforated plate of titanium nickelide with a thermomechanical shape memory. The endoprosthesis consists of the body of the endoprosthesis, the distal and medial ends with the fixing elements at the ends. The body of the endoprosthesis is made in the form of a container for a transplant material, formed by a semi-cylindrical element extending from the perforated plate from the upper edge, having a perforated lobe at the bottom, bent in the direction of the perforated plate until it comes into contact with its lower edge. The gutter for placement of the lower alveolar neurovascular bundle is located at the level of the transition of the semicylindrical element into the perforated lobe from the outside. In the upper part of the bend along the generatrix of the semicylindrical element there is a series of holes with an internal thread for attaching dental implants. A recess was made at the distal end of the endoprosthesis for the formation of two branches having perforations with an internal thread for fixing screws and legs bent at 45 ° angles for attachment to the coronoid and articular processes of the lower jaw. At the end of the medial end of the endoprosthesis, there are two legs bent at an angle of 45 °, for fastening to the preserved bone segments of the lower jaw and perforations with internal thread for the fixing screws.

Novelty of invention

1. The endoprosthesis is made according to the stereolithographic model in the form of a perforated plate of titanium nickelide with a thermomechanical shape memory, a highly inert super-elastic material. Due to the implementation of the shape memory effect, the opening and closing of the elements forming the container is ensured, which makes it easy to place the transplant material in it and then hold it inside the container. Placing the transplantation material inside a container with holes allows it to be additionally secured with screws; optimal conditions for regenerative processes are ensured, which ultimately leads to the restoration of a continuous bone of the lower jaw.

2. The endoprosthesis consists of the body of the endoprosthesis, the distal and medial ends with the fixing elements on the ends. The body of the endoprosthesis is made in the form of a container for a transplant material, formed by a semi-cylindrical element extending from the top edge of the perforated plate, having a perforated lobe in the lower part, bent in the direction of the perforated plate until it comes into contact with its lower edge

3. The gutter for placement of the lower alveolar neurovascular bundle is located at the level of the transition of the semicylindrical element into the perforated lobe from the outside.

4. In the upper part of the bend along the formed semi-cylindrical element there is a series of holes with internal thread for attaching dental implants used as a support for the dentition.

5. A recess was made at the distal end of the endoprosthesis for the formation of two branches, with legs bent at an angle of 45 ° and fixed in the bone during the implementation of the shape-restoration effect and perforated holes with internal thread for installing the fixing screws in the bone of the coronary and articular processes of the lower jaw, which enhances stabilization of the distal end of the prosthesis in the lower jaw remaining after resection. Perforations at the distal end serve to hem the muscles in the anatomically correct position.

At the medial end of the endoprosthesis there are perforations with an internal thread for installing fixing screws, at the end of the medial end of the endoprosthesis there are two legs bent at an angle of 45 °, which are fixed in the bone during the implementation of the shape restoration effect.

6. The internal thread of the perforation holes at the medial and distal ends of the endoprosthesis increases the reliability of stabilization of the endoprosthesis to the preserved segments of the lower jaw with screws.

The set of essential features of the invention allows to obtain a new technical result:

- To create conditions for the transformation of transplantation material, consisting of bone, osteoplastic and osteoregenerative material (for example, “Lioplast”, “Collapan”, “Easy-graft”) into bone tissue in order to recreate the integrity and continuity of the lower jaw due to strong contact and immobilization bone graft with preserved bone segments, preventing the migration of transplant material due to the closure of the petals of the body of the endoprosthesis;

- To increase the strength and reliability of the fixation of the endoprosthesis due to self-locking legs and screws in the perforations of the distal and medial ends of the endoprosthesis equipped with an internal thread;

- Allows you to fix the muscles to the endoprosthesis to the places of their anatomical position, which eliminates the imbalance of chewing function and speech formation.

The presented devices are shown in Fig.1-6.

Figure 1 is a front view of the endoprosthesis.

Figure 2 is a rear view of the endoprosthesis.

Figure 3 is a top view of the endoprosthesis.

Figure 4 is a rear view of the endoprosthesis in oxonometry.

Figure 5 is a rear view of the endoprosthesis in oxonometry with an open cavity of the container.

On figa - radiograph of the patient before surgery.

On Figb - radiograph of the patient after the installation of the endoprosthesis.

On figv - photograph of the endoprosthesis.

On Figg - photograph of the patient after surgery, the 14th day.

The lower jaw endoprosthesis is made of a perforated plate 1 of titanium nickelide having a shape memory effect, inertness, superelasticity, and high adhesive surface properties in accordance with the anatomical and topographic features of the replaced defect according to the stereolithographic model. Computed tomography of the lower jaw is performed in increments of 1 mm. Create a lower jaw model on an automatic prototyping device. The area of the resection of the pathological site of the lower jaw is determined and an endoprosthesis is made in accordance with the parameters of the defect. The endoprosthesis includes a body 2 corresponding to the size of the post-resection defect, the distal 3 and medial 4 ends for fixing the endoprosthesis to the preserved bone segments of the lower jaw (Figure 1, Figure 2, Figure 3). The endoprosthesis body 2 is made in the form of a container for a transplant material, formed by a semi-cylindrical element 5 extending from the perforated plate 1 from the upper edge and having a perforated lobe 6 at the bottom, bent in the direction of the perforated plate 1 until it comes into contact with its lower edge (FIG. 2, FIG. four). The formed cavity of the container is designed to accommodate a bone graft taken from the patient’s iliac wing, osteoplastic and osteoregenerative material which can be used, for example, “Lioplast”, “Collapan”, “Easy-graft”.

The gutter 7 for accommodating the lower alveolar neurovascular bundle is located at the level of transition of the semicylindrical element 5 into the perforated lobe 6 from the outside (Figure 2, Figure 4). In the upper part of the bend along the generatrix of the semi-cylindrical element 5 there is a series of holes 8 with screw thread for installation and attachment of screw dental implants (Figure 3).

At the distal end of the endoprosthesis 3, a recess is made for the formation of two branches 9, with legs 10 bent at an angle of 45 ° for attachment to the coronoid and articular processes of the lower jaw (Figure 2, Figure 3). On the surface of the branches 9 holes are made with an internal thread 11 for fixing screws (Figure 1).

At the end of the medial end of the endoprosthesis 4 there are two legs 12, bent at an angle of 45 °, for fastening to the preserved bone segments of the lower jaw (Figure 2, Figure 3). At the medial end of the endoprosthesis 4, holes 13 with internal thread for fixing screws are located in FIG. 1.

The endoprosthesis is set as follows. A submandibular skin incision is performed, the bone is skeletonized, the muscles attached to the lower jaw are stitched and cut off, the mandibular canal is opened, the neurovascular bundle is isolated, and bone resection is performed within healthy tissues. The position of the medial and distal ends of the endoprosthesis, the correspondence of the body of the endoprosthesis to the size and shape of the post-resection defect are determined. In the intact bone segments of the lower jaw under the legs of the endoprosthesis 10 and 12, intraosseous channels are formed using a cutter. Perforated petal 6 is cooled to a temperature of -5 ÷ 0 ° C and removed from the lower edge of the perforated plate 1 (Figure 5). In the open cavity of the container formed by the semi-cylindrical element 5, a bone graft, osteoplastic and osteoregenerative material are placed, filling it. During the reverse phase transition, the perforated lobe 6 moves to a predetermined position, bending towards the lower edge of the perforated plate 1, thereby holding the transplant material inside the container. If necessary, the transplant material can be additionally fixed with screws through the perforation holes of the lobe 6. The legs of the endoprosthesis at the medial and distal ends of the endoprosthesis are cooled and set at an angle of 90 °. The endoprosthesis is transferred to the wound. The legs 10 of the distal end are installed in the intraosseous canals of the coronary and articular processes of the lower jaw, then the legs 12 are installed in the intraosseous canals formed in the bones of the medial segment of the lower jaw, through the holes with screw threads 11 and 13, additional fixation of the endoprosthesis and bone graft is carried out with screws. The mandibular neurovascular bundle is placed in the gutter 7. The severed muscles are sutured at the site of their anatomical attachment using the perforations of the plate 1, the medial and distal ends of the endoprosthesis. Soft tissue and skin are restored in layers. Complete the operation by temporarily splinting the lower jaw. After the process of regeneration and restoration of the integrity of the lower jaw bone is completed, dental screw implants are installed using screw holes 8 with a screw thread in the upper part of the bend along the half-cylindrical element 5 and prosthetics are performed using implants as a bridge support.

As an example, we provide an extract from the medical history.

The patient M., 52 years old, 02/14/2014, the diagnosis was established: osteosarcoma of the body of the lower jaw (Figa). Computed tomography was performed with a step of 1 mm. A model of the lower jaw is created, the level of resection of the site of the lower jaw affected by the tumor is indicated. In accordance with the parameters of the stereolithographic model of the lower jaw, an endoprosthesis was made (Fig.6c). 04.04.2014, the operation was performed in one stage: tumor resection, reconstructive implant replacement of the lower jaw. On the control orthopantomogram 2 weeks after the operation, the position of the elements of the endoprosthesis is correct (Fig.6b). The movement of the lower jaw in sufficient volume. On Figg photograph of the patient after surgery on the 14th day after surgery. The tire, sutures, healing by primary intention were removed. The patient was referred to an oncology clinic for specialized treatment. When examined on December 16, 2015, the chewing and speech function were not impaired. Orthopedic restoration of the dentition is planned.

Claims (2)

1. An endoprosthesis of the lower jaw to replace a volumetric bone defect of the lower jaw, made individually according to the anatomical and topographic indices of titanium nickelide, with holes for screws, with a groove for placement of the lower alveolar neurovascular bundle, characterized in that the endoprosthesis is made according to the stereolithographic model in the form perforated plate of titanium nickelide with thermomechanical shape memory, consisting of an endoprosthesis body, distal and medial ends with fixing elements at the ends, endo body the prosthesis is made in the form of a container for transplantation material, formed by a semi-cylindrical element extending from the perforated plate’s outgoing edge, having a perforated lobe in the lower part, bent in the direction of the perforated plate to come into contact with its lower edge, the gutter for placement of the lower alveolar neurovascular bundle is located at the transition level a semicylindrical element in a perforated lobe from the outside, in the upper part of the bend along the generatrix of the semicylindrical a series of holes with a screw thread for attaching dental implants is located, a recess is made at the distal end of the endoprosthesis for the formation of two branches with legs at their ends bent at an angle of 45 ° for attachment to the coronoid and articular processes of the lower jaw, two legs are located at the end of the medial end of the implant , bent at an angle of 45 °, for attaching to the preserved bone segments of the lower jaw. 2. Endoprosthesis of the lower jaw, characterized in that the perforation holes at the distal and medial ends have an internal screw thread for fixing screws.

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