Artificial ligament structure for treating scoliosis

Abstract

The invention discloses an artificial ligament structure for treating scoliosis, which comprises an elastic ligament body, the two ends of the elastic ligament body are respectively connected with a pull rope, the suspended ends of the two pull ropes are respectively used for being connected to two adjacent vertebral bodies or transverse processes with scoliosis, and after the pull ropes are fixed, the elastic ligament body is connected with the elastic ligament body. Tension is applied to the two vertebral bodies or transverse processes through resilience force of the elastic ligament body. By the adoption of the artificial ligament structure, during actual operation, the artificial ligament can be fixed through a minimally invasive surgery, and damage of a traditional surgery to spine bone tissue is effectively reduced. After surgical correction treatment, due to resilience force of the artificial ligament, pulling force can be continuously provided until scoliosis is completely recovered. Meanwhile, due to the elastic characteristic of the artificial ligament structure, the patient can have a certain degree of spine activity space, and local stiffness or diseases of adjacent segments can be avoided after surgical correction treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices for scoliosis, and particularly relates to an artificial ligament structure for the treatment of scoliosis. Background Art

[0002] Scoliosis is a common skeletal deformity disease. Please refer to Figure 1 the scoliosis symptoms shown. Its main manifestations are that one or several segments of the spine bend laterally, or there is a spinal deformity accompanied by vertebral rotation, making the back present a C-shaped or S-shaped curve instead of a normal straight line. This abnormal bending phenomenon may occur in any part of the spine, but it is most common in the thoracic and lumbar vertebrae.

[0003] The severity of scoliosis is usually evaluated by the Cobb angle on an X-ray film, which reflects the degree of spinal curvature. According to the different Cobb angles, scoliosis can be divided into mild (less than 20 degrees), moderate (between 20 and 40 degrees), and severe (greater than 40 - 50 degrees or more). Mild scoliosis usually does not require surgical treatment and may only require regular follow-up observations. Children and adolescents may need to wear orthoses to prevent deterioration. Although patients with moderate scoliosis do not need immediate surgery, they need closer monitoring, and orthoses are one of the recommended treatment methods. Severe scoliosis patients often need to consider surgical treatment because they may compress the cardiopulmonary tissues, etc.

[0004] Currently, the generally adopted surgical method is spinal fusion. By using instruments such as metal rods, hooks, and screws to fix the affected vertebrae together and implanting bone graft materials to promote the fusion between adjacent vertebral bodies, over time, these vertebral bodies will grow into a solid whole. This kind of method has the following defects: 1. Symptoms of adjacent segment disease occur. Specifically, after spinal fusion, the unfused adjacent vertebral bodies may bear greater pressure, thus accelerating the degeneration process in these areas and causing new pain or other symptoms.

[0005] 2. Symptoms of upper body stiffness occur. Specifically, because part of the spine is fixed together, the flexibility of this area will be affected, easily causing inconvenience or pain when the patient moves, such as being unable to perform actions like bending over or straightening the waist.

[0006] 3. When connected with a metal rod, the two adjacent spinal segments are tightened after the operation. For adolescent patients, the positions of the two adjacent spinal segments are restricted, which will affect the growth of the spine, and secondary surgery adjustment is required according to the actual situation after the operation. Summary of the Invention

[0007] The object of the present invention is to provide an artificial ligament structure for treating scoliosis. By using this structure, the scoliosis spine can be pulled and corrected. At the same time, because the artificial ligament has elasticity, the patient can have a certain degree of activity, and it will not interfere with the normal growth of the spine.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is: an artificial ligament structure for treating scoliosis, characterized in that: the artificial ligament structure includes an elastic ligament body, and pulling ropes are respectively connected to both ends of the elastic ligament body. The suspended ends of the two pulling ropes are respectively used to be connected to two adjacent vertebral bodies or transverse processes with scoliosis. After the pulling ropes are fixed, the elastic ligament body applies a pulling force to the two vertebral bodies or transverse processes through its resilience.

[0009] Preferably, the elastic ligament body can adopt the following first structure, specifically: the elastic ligament body includes an elastic strip and a first pulling rope that are fixedly connected to each other at the head and tail. The length of the first pulling rope is greater than the normal length of the elastic strip and less than the ultimate tensile length of the elastic strip.

[0010] The elastic ligament body can also adopt the following second structure, specifically: the elastic ligament body includes a plurality of hollow elastic balls, and the plurality of hollow elastic balls are connected in series by a second pulling rope. The second pulling rope is fixed to the side wall of the hollow elastic ball through a limiting member, and the length of the second pulling rope in the inner cavity of each hollow elastic ball is greater than the diameter of the hollow elastic ball and less than the ultimate tensile length of the hollow elastic ball.

[0011] Preferably, the suspended end of the pulling rope can be fixed to the transverse process by winding and tying with a lasso.

[0012] In addition, the suspended end of the pulling rope can also be fixed to the vertebral body by a steel nail. Further, a connecting ring can also be provided at the suspended end of the pulling rope, and the steel nail is fixed to the transverse process after passing through the connecting ring.

[0013] Preferably, the artificial ligament structure is made of a controllable degradation material.

[0014] Specifically, the controllable degradation material is a Fe3O4 nanoparticle-PDLA-PEG copolymer. The Fe3O4 nanoparticle-PDLA-PEG copolymer adopted by the present invention can generate heat through hysteresis loss by magnetic nanoparticles such as Fe3O4 in an alternating magnetic field. If these nanoparticles are embedded in a temperature-sensitive polymer matrix, such as polyethylene glycol PEG and poly (D-lactic acid) PDLA, when an appropriate alternating magnetic field is applied, the magnetic nanoparticles will heat up and cause a phase change or degradation of the surrounding polymer, achieving the purpose of controllable degradation.

[0015] Preferably, the iron oxide nanoparticles-PDLA-PEG copolymer is prepared by an electrospinning process, in which a polymer solution or melt forms slender fibers by applying a high-voltage electric field. When magnetic nanoparticles are added to the spinning solution, fibers containing uniformly dispersed magnetic particles can be obtained.

[0016] The beneficial effects of the present invention are as follows: By adopting the artificial ligament structure of the present invention, based on different degrees of scoliosis, after surgical correction and treatment, due to its resilience, it can continuously provide tension until scoliosis is completely restored. At the same time, due to the elastic characteristics of the artificial ligament structure, it can give the patient a certain degree of spinal movement space, and after surgical correction and treatment, it can avoid local stiffness or adjacent segment diseases.

[0017] In addition, compared with traditional spinal correction surgeries, the artificial ligament structure of the present invention is used for pulling the transverse processes of the spine, and minimally invasive surgery can be used to fix the artificial ligament, effectively reducing the damage to the spinal bone tissue caused by traditional surgeries. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of an artificial ligament structure of the present invention.

[0019] Figure 2 is Figure 1 a schematic structural diagram of the artificial ligament structure shown fixed on the transverse process.

[0020] Figure 3 is Figure 1 a schematic structural diagram of the artificial ligament structure shown with a connecting ring.

[0021] Figure 4 is Figure 3 a schematic structural diagram of the artificial ligament structure shown fixed on the vertebral body.

[0022] Figure 5 is Figure 4 an enlarged schematic diagram of part A in

[0023] Figure 6 a schematic structural diagram of an artificial ligament structure of the present invention.

[0024] Figure 7 is Figure 6 a sectional schematic diagram of the artificial ligament structure shown.

[0025] Figure 8 is Figure 7 an enlarged schematic diagram of part B in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The present invention will be further described in detail below with reference to the accompanying drawings. Example 1

[0027] As Figure 1 shown, the artificial ligament structure disclosed by the present invention includes an elastic ligament body 1, and drawstrings 2 are respectively connected to both ends of the elastic ligament body 1. Among them, the elastic ligament body 1 adopts the following structure, which includes an elastic strip 11 and a first pulling rope 12 that are fixedly connected to each other at the head and tail, and the length of the first pulling rope 12 is greater than the normal length of the elastic strip 11 and less than the ultimate tensile length of the elastic strip 11. In this way, when being pulled, the first pulling rope 12 can protect the elastic strip from being over-pulled and prevent the situation of being broken, ensuring the effect.

[0028] During surgical application, according to different case conditions, information such as the thickness and length of the elastic strip of the artificial ligament is determined according to the actual situation to ensure that appropriate elasticity can be provided. For the fixation of the artificial ligament, in actual application, it can be fixed on the transverse process of the spine or on the vertebral body.

[0029] The first situation: As Figure 2 shown is the state where the artificial ligament is fixed on the transverse process. The suspended ends of the two drawstrings 2 are respectively wound around the transverse process and fixed by the way of tying with a noose. After the drawstrings are fixed, the scoliosis spine can be corrected. Since the elastic ligament body 1 has elasticity, it can not only apply a pulling force to the two transverse processes to keep the spine in the corrected state, but also enable the spine to have a movement space, avoiding the problem of local stiffness in the corrected part in traditional surgeries.

[0030] The second situation: As Figure 3 shown, a connecting ring 3 is also connected to the suspended end of the drawstring 2. Figure 4 、 5 are the states where the artificial ligament is fixed on the vertebral body. When implementing the fixation operation, the steel nail 4 is passed through the connecting ring 3 and then fixed on the spinal vertebral body.

[0031] Preferably, the artificial ligament structure can also be made of a controllable degradation material. In this way, there is no need to perform another operation to remove the artificial ligament after the operation, which can reduce the burden on the patient.

[0032] Specifically, the above-mentioned controllable degradation material is a Fe3O4 nanoparticle-PDLA-PEG copolymer. The Fe3O4 nanoparticle-PDLA-PEG copolymer adopted by the present invention can generate heat through hysteresis loss by magnetic nanoparticles such as Fe3O4 in an alternating magnetic field. If these nanoparticles are embedded in a temperature-sensitive polymer matrix, such as polyethylene glycol PEG and poly (D-lactic acid) PDLA, when an appropriate alternating magnetic field is applied, the magnetic nanoparticles will heat up and cause a phase change or degradation of the surrounding polymer, achieving the purpose of controllable degradation.

[0033] In addition, the Fe₃O₄ nanoparticles-PDLA-PEG copolymer is prepared by an electrospinning process, where a polymer solution or melt forms slender fibers by applying a high-voltage electric field. When magnetic nanoparticles are added to the spinning solution, fibers containing uniformly dispersed magnetic particles can be obtained. Example 2

[0034] The difference between this example and Example 1 lies in that another structure of the elastic ligament body is adopted, such as Figures 6 - 8 shown, the elastic ligament body includes a plurality of hollow elastic balls 21. Among them, a plurality of hollow elastic balls are connected in series by a second pulling rope 22, and the second pulling rope 22 is fixed to the side wall of the hollow elastic ball through a limiting member 23.

[0035] Specifically, the length of the second pulling rope in the inner cavity of each hollow elastic ball 21 is greater than the diameter of the hollow elastic ball and less than the ultimate tensile length of the hollow elastic ball 21. With such a design, when pulling, the second pulling rope in the inner cavity of the hollow elastic ball 21 can protect the hollow elastic ball from being over-pulled and prevent the situation of being pulled off, effectively ensuring the effect.

[0036] Through the introduction of the above two examples, a clear understanding of the artificial ligament structure of the present invention has been obtained. Next, the operation process during specific application will be further described.

[0037] 1. Obtain the whole-body standing position image of the scoliosis patient through the EOS imaging system to evaluate the morphology of the spine.

[0038] 2. Use a handheld or fixed 3D scanner to perform non-contact scanning on the patient's body to quickly obtain an accurate three-dimensional model. The scanned data can be directly reconstructed into a digital model of the patient's body in the Materialise Mimics inPrint software on the computer. Superimpose the patient's X-ray film on the 3D body model to ensure that the correction force points can be accurately located at the positions that need to be corrected. Through software analysis, the appropriate artificial ligament fixation points can be calculated, which are the appropriate positions for relieving the scoliosis stress.

[0039] 3. Use finite element analysis software (FEA) to perform detailed simulations of different correction strategies and their effects to obtain the parameter information related to the suitable artificial ligament.

[0040] Specifically, the Abaqus software can be used for analysis, and the process is as follows: clarify the specific objectives achieved through FEA (stress distribution of the spine under different correction forces, determine the position, direction, and tensile force of the artificial ligament, material selection, shape, size, quantity, etc.). Import the 3D body model obtained from the above Materialise Mimics inPrint software into Abaqus, define the boundary conditions and constraints, determine the fixed points and other constraint conditions in the model, and simulate the state of natural human standing. Define the material properties, set the material characteristics of bones, intervertebral discs, and other soft tissues, such as elastic modulus, Poisson's ratio, nonlinear behavior, etc., set the material and shape of the artificial ligament, and input accurate parameters such as elastic modulus and Poisson's ratio. Mesh generation, use the automatic or manual mesh generation function of Abaqus to ensure that the mesh quality is high enough to capture important mechanical details while maintaining the calculation efficiency. Pay attention to appropriately increasing the mesh density in the stress concentration area or where the deformation is large. Apply loads and boundary conditions, based on clinical needs, reasonably apply correction forces, set the contact surface between the artificial ligament and other structures, consider factors such as the friction coefficient, and reasonably set the boundary conditions to simulate the scoliosis situation analysis in some postures such as walking, lying down, sitting, bending, etc. Solver configuration and operation, select the appropriate solver type (static, dynamic, or quasi-static solver), consider using a dynamic solver according to the scoliosis project recommendations to ensure that the solver can reach a stable solution within a reasonable time. The simulation can obtain reasonable material and shape information of the artificial ligament. Finally, obtain the required shape parameter information of the artificial ligament according to the simulation results.

[0041] 4. Fabricate an artificial ligament structure with matching parameters based on the artificial ligament information obtained from the simulation.

[0042] 5. Perform minimally invasive surgery to fix the artificial ligament structure of the present invention to correct the scoliosis spine.

[0043] 6. In a period of time after the operation, continue to evaluate whether there is a tendency to deteriorate. The evaluation is usually based on imaging examinations (such as X-rays), and is determined by measuring the change in the Cobb angle. For doctors to determine subsequent treatment methods.

[0044] The above content is only used to illustrate the technical solution of the present invention. Any simple modification or equivalent replacement made by those of ordinary skill in the art to the technical solution of the present invention shall not depart from the essence and scope of the technical solution of the present invention.

Claims

1. An artificial ligament structure for treating scoliosis, characterized in that: The artificial ligament structure includes an elastic ligament body, and the two ends of the elastic ligament body are respectively connected to pull ropes. The suspended ends of the two pull ropes are respectively used to connect to two adjacent vertebrae or transverse processes with scoliosis. After the pull ropes are fixed, tension is applied to the two vertebrae or transverse processes through the resilience of the elastic ligament body.

2. The artificial ligament structure for treating scoliosis according to claim 1, characterized in that: The elastic ligament body comprises an elastic strip and a first pulling rope which are fixedly connected at the head and tail, respectively. The length of the first pulling rope is greater than the length of the elastic strip in a normal state and less than the ultimate stretching length of the elastic strip.

3. The artificial ligament structure for treating scoliosis according to claim 1, characterized in that: The elastic ligament body includes a plurality of hollow elastic balls, which are connected in series through a second pulling rope, and the second pulling rope is fixed to the side wall of the hollow elastic ball through a limiter, and the length of the second pulling rope in the inner cavity of each hollow elastic ball is greater than the diameter of the hollow elastic sphere and less than the maximum stretching length of the hollow elastic sphere.

4. The artificial ligament structure for treating scoliosis according to any one of claims 1 to 3, characterized in that: The suspended end of the pull rope is wrapped around the rope and tied and fixed on the transverse process.

5. The artificial ligament structure for treating scoliosis according to any one of claims 1 to 3, characterized in that: The suspended end of the pull rope is fixed on the vertebral body through a steel nail.

6. The artificial ligament structure for treating scoliosis according to claim 5, characterized in that: The suspended end of the pull rope is also connected with a connecting ring, and the steel nail passes through the connecting ring and is fixed on the transverse process.

7. The artificial ligament structure for treating scoliosis according to any one of claims 1 to 3, characterized in that: The artificial ligament structure is made of controllable degradation material.

8. The artificial ligament structure for treating scoliosis according to claim 7, characterized in that: The controllable degradation material is ferrosoferric oxide nanoparticle-PDLA-PEG copolymer.

9. The artificial ligament structure for treating scoliosis according to claim 7, characterized in that: The ferrosoferric oxide nanoparticle-PDLA-PEG copolymer is prepared by an electrospinning process.

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