RU217616U1 - Telescopic body-replacing spine implant - Google Patents

Abstract

The utility model relates to medicine, namely to traumatology, orthopedics, neurosurgery and vertebrology, and can be used to restore the functions of the anterior support complex of the spinal column after resection of one or more vertebral bodies in the surgical treatment of diseases and injuries of the spine, in the process of performing anterior spinal fusion on cervical and thoracolumbar levels. The utility model is aimed at solving the problem of creating a device - a telescopic body-replacing implant of the spine, taking into account the features of the additive manufacturing method, which ensures reliable fixation of the implant in the operated segment of the spine. The technical result of the proposed utility model is to reduce the risk of implant migration in the intra- and postoperative period, which can significantly increase its original size. The implementation of the technical problem and the claimed result is achieved by manufacturing a telescopic body-replacing implant of the spine, including three connected tubes, made of titanium alloy VT 1-00 with holes using the SLM selective laser melting method, while the inner tube has oppositely directed threads on the inner and outer surfaces , the side surface of the tubes includes through holes with teeth on the outer ends of the tubes, and the fixing of the lower and upper tubes relative to the inner one is carried out using locking rings. 4 ill.

Description

The utility model relates to medicine, namely to traumatology, orthopedics, neurosurgery and vertebrology, and can be used to restore the functions of the anterior support complex of the spinal column after resection of one or more vertebral bodies in the surgical treatment of diseases and injuries of the spine, in the process of performing anterior spinal fusion on cervical and thoracolumbar levels.

It is known that lesions of the spine of various origins with impaired support ability and progressive deformity of the spinal column are a difficult medical problem. The main tasks in the treatment of patients with lesions of the spine are: the elimination of compression of the neural structures, the restoration of the support ability of the spine. For this, various methods and devices of surgical treatment are used, for example, body-replacing implants. An important task is to select the implant design for the parameters of the damaged vertebrae [Prudnikova O.G. Surgery for spinal deformities in adults: current problems and approaches to treatment // Orthopedic genius. - 2015. - No. 4. - S. 94-102].

Known mesh endoprosthesis (implant) of the vertebra, made in the form of a hollow cylinder with through side holes. The method of implantation of the endoprosthesis consists in removing the body of the damaged vertebra and implanting the endoprosthesis instead of the resected vertebra or vertebrae [Harms J Instrumented spinal surgery Principles and techniques-Thieme, Stuttgart - New York, 1999. - P. 198]. The disadvantage of the mesh endoprosthesis is its fixed height, which may not coincide with the height of the gap between the bodies of healthy vertebrae in the operated segment after resection of injured vertebrae. Endoprosthesis replacement is associated with problems of restoring anatomical forces on adjacent vertebrae. Errors in choosing the length of the endoprosthesis at the stage of its formation before installation in the intervertebral space of the spine can lead to a number of postoperative complications.

Known telescopic prostheses of the vertebral body:

- RF patent No. 2520799 dated March 19, 2013. Telescopic prosthesis of the vertebral body and the method of its implantation / Chertkov A.K., Chertkov A.A., Chertkov K.A., Gusev D.A., - RF patent No. 2428146 dated 10.24.2008. Implant for installation between the bodies of the vertebrae of the spine / Kast E.,

- patent of the Russian Federation No. 2443400 dated 01/16/2008. Intervertebral implant with an elastic structural element / Richter M., Hamich S., Willmann N.,

- "Obelisk" company Ulrich medical, Germany. Vertebral body prosthesis for operations on the thoracic and lumbar spine / https://www.medicalexpo.ru, product-70397-722173, see also Synex II, TeCorp, X-Tenz, XPand/XPand-R, ADD plus,

- patent US 20120016478, publ. 01/19/2012. Intervertebral implant with multi-piece end cap / Bret M. Wilfong, Michael J. Merves // patents.google.com>patent/ US20120016478Al/en,

- patent US 20110218631, publ. 09/08/2011. Adjustable intervertebral implant / www.uspto.gov.,

- international application WO No. 2008112923, publ. 09/16/2008,

- RF patent 140742 dated 01/29/2014. Adjustable endoprosthesis of the vertebral body / Nazarov Yu.K., Lunev SV, Gramolin K.V., Grushevsky N.V., containing an upper cylindrical base with an upper support platform, a lower cylindrical base with a lower support platform, an annular coupling and means for fixing the height prosthesis. Cylindrical bases and platforms are made with slots and holes. The upper cylindrical base is made with an external thread, the annular sleeve - with an internal thread. Together they represent a screw pair, while the lower cylindrical base with an annular coupling form a movable connection. During installation, the endoprosthesis is placed between healthy vertebrae, then the cylindrical bases are moved apart by rotating the annular sleeve until their supporting areas are in tight contact with the bodies of adjacent healthy vertebrae, after which the endoprosthesis is fixed in this position with a screw. These endoprostheses are characterized by the complexity of design and installation, as well as the presence of a specialized tool. The designs of these endoprostheses do not provide reliable fixation in the presence of a locking screw to fix the position of the support areas in the intervertebral space, which can be moved in the early postoperative period.

Known endoprosthesis of the vertebral body for minimally invasive fusion in the form of a hollow cylinder. Along the circumference, the cylinder has dividing grooves for cutting the cylinder, located at a distance and relative to each other at angles, passing through rows of holes on its front and posterolateral surfaces and conditionally dividing the endoprosthesis into sections. On the anterolateral surface there is a longitudinal row of holes intended for the installation of a fixing device. The tool for implantation of the said hollow endoprosthesis of the vertebral body with a fixing device of the endoprosthesis is made in the form of an impactor key [RF Patent 2615863 dated 12.05.2015. Endoprosthesis of the vertebral body for minimally invasive (thoracoscopic) fusion, a tool for implanting an endoprosthesis with a fixing device and a method for installing the claimed endoprosthesis using the claimed tool and fixing device / Gribanov A.V.]. However, this endoprosthesis is quite complicated in design.

A method of implantation of a body-replacing vertebra is known, including resection of the damaged vertebra and the introduction of a telescopic implant representing a central hollow rod with a thread differently directed from its center, having through longitudinal grooves, on which half-shells with teeth on the outer ends are screwed on from different sides, equipped with L-shaped plates with holes for screws and windows, the edges of which reach almost to the ends of the semi-corpuses (RF Patent 2663641 dated February 3, 2016. Telescopic body-replacing implant of the vertebra "las-3" and the method of its implantation / Nekhlopochin A.S., Nekhlopochin S.N.). The windows are designed to fill the internal cavity of the implant with a natural or artificial filler, and the half-shells also have through radial side holes. In the semi-hulls between the windows and the inner ends, solid jumpers are made, providing the possibility of forced deflection in the direction towards the longitudinal central axis of the implant without significant efforts to fix the semi-hulls relative to the stem. The implant stem is pre-filled with crushed filler. After the implant is installed, the spine is distracted by unscrewing the rod to maximize the length of the implant. Then, the required amount of filler is added to the internal cavity until it is completely filled, after which the filler is compacted by reducing the total length of the telescopic implant, followed by its fixation with the help of L-shaped plates attached to the vertebrae adjacent to the resected ones, the bridges on the half-cases bend towards the longitudinal central axis of the implant by applying radial forces to them from the outside until the jumpers are lowered into the longitudinal grooves of the stem, with thread blocking and fixation of the implant half-shells relative to the stem. Disadvantages: 1) the imperfection of its design, which, while ensuring reliable fixation of the vertebral motor segment of the retaining rings, can allow the semi-hulls to scroll; 2) the use of separate additional plates for fixation complicates spinal fusion - prototype.

The utility model is aimed at solving the problem of creating a device - a telescopic body-replacing implant of the spine, taking into account the features of the additive manufacturing method, which ensures reliable fixation of the implant in the operated segment of the spine.

The technical result of the proposed utility model is to reduce the risk of implant migration in the intra- and postoperative period, which can significantly increase its original size.

The implementation of the technical problem and the claimed result is achieved by manufacturing a telescopic body-replacing implant of the spine, including three connected tubes, made of titanium alloy VT 1-00 with holes using the selective laser melting "SLM", while the inner tube has oppositely directed threads on the inner and outer surfaces , the side surface of the tubes includes through holes with teeth on the outer ends of the tubes, and the fixing of the lower and upper tubes relative to the inner one is carried out using locking rings.

The developed design of the implant is illustrated in Fig. 1-4:

fig. 1 - the sequence of manufacturing the implant blank by the SLM method, where: a - preparation of the control program for printing, 6 - blanks after cutting from the build platform, c - synthesized blanks on the build platform,

fig. 2 - telescopic body-replacing implant of the spine, a) in the initial position, b) in the working position, 1 - upper tube, 2 - inner tube, 3 - lower tube, 4 - upper tube retainer, 5 - lower tube retainer, 6 and 8 holes , 7 - teeth,

fig. 3 - detail of the telescopic body-replacing implant of the spine, where: a - the upper tube of the implant; 6 - inner tube of the implant, c - outer (or lower) tube of the implant, 4 - holes, 5, 6 - retaining rings (retainers),

fig. 4 - detailing of the clamps, where: a - retaining ring of the upper tube, 6 - retaining ring of the lower tube.

An example of the implementation of the PM. Example 1, the manufacture of the implant.

The development of drawings and CAD 3D models was carried out sequentially on the basis of individual stages of the development of the implant design. To check the calculated data, each part of the product was grown using a digital CAD model on a photopolymer 3D printer. Photopolymer resin "Resione ABS Like 3D K Black" was chosen for the manufacture of parts. After clarification and adjustment of the structural elements of the implant, the technological process for manufacturing experimental samples from the alloy 12X18H10T by the method of selective laser melting at the SLM Solutions 280 facility was worked out. The fabricated samples made it possible to test the method of selective laser melting on small structural elements. The synthesis of overhanging sections in holes and sharp edges was worked out, Fig. 1. Thanks to the proven SLM modes of the source material, the structural elements of the product were printed without much difficulty.

The final stage was the production of a prototype telescopic body-replacing implant of the spine using the SLM method with commercially pure titanium grade VT 1-00 according to (GOST 19807 - 91), Fig. 2-4, commonly used for the manufacture of implants (GOST R ISO 5832-2-2014. Implants for surgery. Metallic materials. Part 2: Unalloyed titanium).

Description of the device.

The main mechanism that ensures the operation of the proposed implant-endofixator is a bilateral tube-lift 2, coupled with tubes 1 and 3, which together, along with the distraction force, guarantee the maintenance of the required height of the implant under conditions of significant axial loads. Bringing the device to the installation site in the resection area is carried out using a well-known locking handle according to the prototype [RF patent No. 202854 dated 10/15/2020. Telescopic body-replacing implant of the spine / Peretsmanas E.O., Esin I.V.]. The locking handle is rigidly attached to the holes 6 and 8 on the tubes 1-3 of the implant. Fixation of the tubes is carried out with the help of two locking rings 4 and 5. The inner part of the locking handle from the distal end has grippers, which, when the inner tube is fixed, are mated with the outer tubes. The proximal end of the outer part of the locking handle is provided with a grip handle and allows rotational movement. The large length of the handle and its tight attachment to the device allows you to position the implant in the operating area. After the placement of the implant-endofixator in the area of the resected part of the vertebra, it is opened. To this end, with a tight grip on the inner tube 2, its sequential rotation relative to the tubes 1 and 3 is carried out, followed by fixing the clamps 4 and 5. The extension of the implant-endofixator is carried out in such a way that the teeth 7 of the implant firmly rest against the adjacent vertebrae.

Example 2, clinical.

Patient N., 44 years old. Open surgical treatment of injuries of the lumbar vertebrae L2, L3, L4 type A4 (AO/Spine). On the basis of X-ray images, a preliminary assessment of the size of the implant for installation in place of damaged vertebrae was carried out, Fig. 2.

Resection of vertebral bodies L2, L3, L4 was performed. After the removal of the bodies, a bone tissue defect was formed with a length of approximately 13.0 cm. A telescopic body-replacing implant of the developed design was implanted into the defect between the bodies L1 and L5 from the anterior retroperitoneal left-sided access. The implant was filled with osteogenic hydroxyapatite to ensure the formation of a metal-bone block in the postoperative period. To correctly restore the height of the affected area of the spine, tubes 1 and 3 were advanced under controlled untwisting of tube 2. The inner tube 2 was fixed relative to the outer tubes 1 and 3 using retaining rings in the area of the accessible surgical field. The mesh structure of the implant allows reliable formation of the bone block inside and outside the implant.

Thus, an implant was formed between the vertebrae, replacing an extended defect after the removal of the vertebrae L2, L3, L4, creating conditions for the consolidation of the affected spinal segments. In the postoperative period, complications, secondary delayed deformities of the operated segment were not observed. After 8 months, a bone block was formed in the operation area.

Claims (1)

Telescopic body-replacing implant of the spine, characterized in that it includes three telescopically connected tubes: inner, lower and upper, while the inner tube has oppositely directed threads on the inner and outer surfaces, and the ability to interface with the lower and upper tubes, the side surface of the tubes includes through holes , and on the outer ends there are teeth that can rest against adjacent vertebrae, and the lower and upper tubes are fixed relative to the inner tube by means of locking rings.

Images