RU2365357C2 - Composit implant for repair of lower jaw defects - Google Patents

Abstract

FIELD: medicine; surgery.

SUBSTANCE: composite implant is executed from titan nickelide and contains a wire supporting basis. The composite implant includes a condyle, a periosteal coverage and an attachment retainer. The supporting basis is coupled with the attachment retainer and the condyle. The supporting basis is executed in size of bone defect to condyle basis level - in the form of the dual spiral formed by convolutions of the eight-figurative form, with continuation in the form of a single spiral on a piece, equal to length of a condyle neck. The attachment retainer contains the wire rods and an arch for plunging in a healthy bone fragment from one side, and two spring-actuated loops for insertion in the free end of an eight-figurative spiral - from the other side. The condyle contains a head for implantation in an articulate pole of a temporal bone from one side, and a neck for installation in the free end of a single spiral from the other side. The mentioned neck is executed from two twisted wire branches encircling the condyle head from above. The periosteal coverage is executed in the form of an elastic porous penetrable layer with thickness from 2 to 10 mm, executed in the form of mesh linen from ligature threads, distributed round a surface of the support basis in a circular manner and the attachment retainer and the condyle coupled with it.

EFFECT: replacement of not only form-building and supporting defects of a lower jaw bone fragment, but also accompanying periosteal coverage and condyle defects, stable implant bracing to a healthy bone fragment.

2 cl, 1 ex, 7 dwg

Description

The invention relates to medicine, namely to reconstructive maxillofacial surgery, and can be used in traumatology, orthopedics, and oncology for arthroplasty of complex defects of the lower jaw.

As you know, the lower jaw consists of bone tissue covered with an interacting periosteum, contains two articular heads that interact with the articular fossa of the temporal bones. The success of reconstruction of an extensive defect of the lower jaw as a whole depends on the design features of its constituent elements and the possibility of their interaction.

An endoprosthesis is known - a fixative for reconstructing defects of the lower jaw, having end parts in the form of rods placed intraosseously and an arc connecting the rods placed in a previously prepared bed. (Patent RU No. 2285500, IPC A61F 2/28).

However, this endoprosthesis is designed to provide a fixed connection with a bone fragment and is designed to integrate only with bone structures.

An implant for replacing extended bone fragments of complex shape from an alloy based on titanium nickelide is also known. It contains a formable support base made in the form of a wire spiral covered with a mesh material along its entire length and an element of communication with the surrounding tissue is attached to it. (Patent RU No. 2265417, IPC A61F 2/28).

However, with extensive defects of the lower jaw, the use of this implant also does not provide satisfactory replacement of the defect, since the modeling of its contours using a single cylindrical spiral is not effective enough to restore the anatomical shape.

In addition, the use of granules of porous permeable titanium nickelide as an element of communication with the surrounding tissue does not provide reconstruction of the periosteum and the interaction of the endoprosthesis with tendon-muscle tissues. This causes a change in the spatial ratio of the axles of muscle traction, changes in the moments of forces, and a violation of the biomechanics of the lower jaw. Such defects lead to irreversible severe functional impairment and significantly reduce the quality of life and functional rehabilitation of patients.

In addition, the implant for replacing extended bone fragments of complex shape does not contain an individual element for reconstruction of the condyle defect and an individual element for fixing to a healthy bone fragment.

The objective of the invention is to replace not only the formative and supporting defects of the bone fragment of the lower jaw, but also the accompanying defects of the periosteum and condyle, as well as ensuring a stable connection of the endoprosthesis with a healthy bone fragment.

The problem is solved due to the fact that the composite endoprosthesis for the reconstruction of defects of the lower jaw, made of titanium nickelide and containing a support base of wire, according to the claimed invention, the composite endoprosthesis has a condyle, periosteum and retainer, the support base is connected to the fixator and condyle, the support base is made by the size of the bone defect to the level of the base of the condyle - in the form of a double helix formed by turns of an eight-shaped shape, with a continuation in the form of a single spiral on a segment equal to lengths e neck condyle, the retainer contains wire rods and an arch for immersion in a healthy bone fragment on one side and two spring-loaded loops for insertion into the free end of the eight-shaped spiral - on the other hand, the condyle contains on one side a head for implantation in the articular fossa of the temporal bone, and on the other hand, a neck for installation in the free end of a single spiral, while the said neck is made of two twisted wire branches, covering the condyle head from above, the periosteum is made in the form of elastic porous permeable layer thickness of from 2 to 10 mm formed in a mesh web of ligature strands circularly distributed around the surface of the support base and connected thereto and retainer condyle.

The mesh fabric is made of a width of 40-50 mm from ligature yarns with a thickness of 70-120 μm, connected by facial loops with the formation of cells of 1.5-3.5 mm.

The invention is illustrated by the drawing, which shows in figure 1, 2 - the supporting basis of the bone defect (front view and left, respectively); figure 3 - latch; figure 4 - condyle; figure 5 - mesh fabric from which the periosteum is formed; Fig.6, the claimed endoprosthesis to the formation of an elastic permeable layer (periosteum); Fig.7 - composite endoprosthesis of the lower jaw assembly.

A composite endoprosthesis for the reconstruction of defects of the lower jaw is made of titanium nickelide and according to the claimed invention contains:

- a support base of wire with a diameter of preferably 2 mm, made according to the size of the bone defect to the level of the base of the condyle - in the form of a double helix 1 formed by rounds of an eight-shaped shape, continued as a single helix 2 on a segment equal to the length of the neck of the condyle (to the level of the articular head );

- a retainer 3, containing wire rods 4, 5 and an arch 6, immersed in a healthy bone fragment 7 on the one hand, and two spring-loaded loops 8 inserted into the octal-shaped spiral 1 of the support base, on the other hand, to ensure their connection. Thus, through the retainer, the support base is connected with a healthy bone fragment 7;

- the condyle of the lower jaw, containing on one side the articular head 9 for implantation in the articular fossa of the temporal bone, and on the other a neck 10 of two twisted wire branches, the combined diameter of which corresponds to the inner diameter of a single spiral 2 of the supporting base;

- the periosteum 11 is an elastically porous permeable layer, from 2 to 10 mm thick, made of a mesh web 12, circularly distributed around the surface of the support base of the bone defect and the fixator and condyle connected to it for individual modeling of the anatomical shape and integration with the surrounding tendon-muscle structures driving the mandibular bone.

The mesh fabric 12 is made of ligature threads with a diameter of from 70 to 120 microns by knitting with facial loops. Tissue adaptation of the elements of the endoprosthesis in the field of reconstruction of the defect of the lower jaw occurs due to reparative tissue regeneration. Experimental studies have shown that the use of threads with a diameter of less than 70 microns is impractical due to a decrease in the strength of the fabric, and with a diameter of threads greater than 120 microns, the elasticity of the structure decreases. The optimal width of the mesh web from the point of view of modeling an individual anatomical shape is 40-50 mm, and to ensure the most favorable conditions for cellular reparative regeneration and tissue adaptation, the mesh web should have cells 1.5-3.5 mm in size.

In the individual manufacture of the above components of the composite endoprosthesis, plastic prototypes of the jaw bones of patients are used, obtained on the basis of data from a multi-helical computed tomography (CT) scan using 3-D computer technologies.

Reconstruction of a defect in the lower jaw begins with the formation of a receptive bed on the healthy bone fragment 7 with a milling cutter for installing the arc 6 and holes for the fixing rods 4, 5. After that, a healthy bone fragment 7 is bandaged with two turns of a mesh web and wire rods and an arch are placed in the prepared bed, after which a healthy bone fragment 7 is re-bandaged over the fixation elements and the rest of the mesh cloth is held.

The other end of the clamp, made in the form of two identical spring-loaded wire loops 8, is connected to the support base of the bone defect by introducing the spring-loaded wire loops 8 into the corresponding inner diameter of the double eight-shaped wire spiral 1. The free end of the support base, made in the form of a single spiral 2, is connected to the condyle by introducing the neck of the 10 condyle into the inner diameter of the single helix 2. In this case, the articular head 9 of the condyle is topographically oriented for precise implantation in the joint hydrochloric fossa of the temporal bone.

Then, the remaining part of the mesh web 12 retained after bandaging of the healthy bone fragment 7 is circularly distributed around the entire outer surface of the solid structures of the composite endoprosthesis and the periosteum is formed in the form of an elastic porous permeable layer with a thickness of 2 to 10 μm depending on the anatomical features of a particular patient, namely depending on the initial volume of muscle mass of the maxillary tissue, after which the articular head 9 is implanted into the articular fossa of the temporal bone.

The effectiveness of the composite endoprosthesis during the reconstruction of defects of the lower jaw is confirmed by numerous clinical trials.

Example.

Maxillofacial Department GB No. 11, Omsk, medical history No. 177, dated February 25, 2005. Patient S., 26 years old, sick 6 years. Diagnosis: recurrent suppurative ameloblastoma of the lower jaw on the right with a spread of 34 teeth, damage to the body, branch, condyle, coronoid process with 2.5 cm germination in the left temporal region. Opening of the mouth by 1 cm.

Based on a plastic prototype of the bones of the facial skull, including the mandibular bone, obtained using multislice CT and computer 3-D technologies, the design, modeling and fitting of products from four articulated endoprostheses - the supporting base of the bone defect, fixative, condyle and periosteum, were performed.

Under endotracheal anesthesia, a tumor-affected fragment was removed from the submandibular access to the left with exarticulation of the temporomandibular joint. During the operation, the sections of muscles cut off from the corresponding surfaces of the removed jaw fragment are taken on ligatures:

a) the submental-hyoid, the bottom of the oral cavity, the anterior abdomen of the biceps muscle;

b) medial pterygoid, lateral pterygoid;

c) chewing, temporal muscles.

On a healthy bone fragment, a bone bed was formed under the rods and the retainer arc. After installing the rods and the arc in the above sequence, the other end of the retainer was articulated with the support base of the bone defect using two spring-loaded wire loops inserted into the lumen of an eight-shaped wire spiral. The condyle neck was inserted into the distal portion of the support base of the bone defect made in the form of a single helix, and the condyle head, previously topographically oriented, was implanted into the articular fossa.

The formation of an elastic-elastic permeable layer around the common surface of the assembled endoprosthesis was carried out by circular distribution of the mesh web and ligation of its elements.

After the endoprosthesis is fully installed, distal sections of all the above muscle groups are sutured to the surface of the endoprosthesis to the places of their physiological attachment, suturing of soft tissues over the endoprosthesis, installation of active drains, suturing of the skin.

The postoperative period proceeded against the background of drug therapy without inflammatory complications. The configuration of the lower jaw was restored, the state of the bite was adequate, the volume of the main functional movements of the jaw was restored after 2 months. The long-term observation period is more than 2 years. Functional and clinical examination data reliably confirm the presence of muscle mass, and functional tone, and the interaction of synergistic and antagonistic muscle groups attached to the surface of the endoprosthesis. There are relevant radiological data attached to the application materials.

Thus, the invention provides reconstruction of the formative and supporting defects of the bone fragment and the corresponding defects of the periosteum and condyle of the lower jaw, and in addition, provides a stable connection between the endoprosthesis and a healthy bone fragment, which makes it possible to achieve anatomical and functional compliance with endoprosthetics.

Claims (2)

1. A composite endoprosthesis for the reconstruction of defects of the lower jaw, made of titanium nickelide and containing a support base of wire, characterized in that the composite endoprosthesis has a condyle, periosteum and fixator, the support base is connected to the fixator and condyle, the support base is made up to a bone defect up to condyle base level - in the form of a double helix formed by turns of an octagonal shape, with a continuation in the form of a single spiral on a segment equal to the length of the neck of the condyle, the retainer contains wire rods and an arch for immersion in a healthy bone fragment on one side and two spring-loaded loops for insertion into the free end of the eight-shaped helix - on the other hand, the condyle contains on one side a head for implantation in the articular fossa of the temporal bone, and on the other a neck for installation in the free the end of a single spiral, while the said neck is made of two twisted wire branches covering the condyle head from above, the periosteum is made in the form of an elastic porous permeable layer with a thickness of 2 to 10 mm, made in the form of a mesh web of ligature threads, circularly distributed around the surface of the support base and the retainer and condyle connected to it. 2. The composite endoprosthesis according to claim 1, characterized in that the mesh web is made of a width of 40-50 mm from ligature yarns with a thickness of 70-120 μm, connected by facial loops with the formation of cells 1.5-3.5 mm

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