Mesh belt structure for treating spondylolisthesis

Abstract

The invention discloses a net belt structure for treating spondylolisthesis, which is H-shaped and comprises an upper pair of stay cords, a lower pair of stay cords and a stay cord connecting part surrounding the spine, the rope ends of the two pairs of pull ropes are connected to the upper spine and the lower spine with the slipping spine respectively, and the net belt structure exerts pulling force on the upper spine and the lower spine through the pull ropes so as to pull the slipping spine. Another scheme is provided for a patient who is not suitable for an existing steel plate and steel nail resetting mode, and the end of the mesh belt can be fixed through steel nails; for people with low bone mineral density, for example, old people, the mesh belt structure connected by the lasso can be used, and after an operation, the vertebral pedicle can be repaired by combining a bone transplantation mode and the like with a treatment mode of the lasso. The mesh belt structure can be prevented from being stiff after an operation, and certain activity of the spine is reserved. Compared with an existing operation, the surgical process has less damage to bone tissue, and minimally invasive surgery can be achieved under certain specific conditions.

Description

Technical Field

[0001] The present invention relates to a medical device for the treatment of spondylolisthesis, and particularly to a mesh belt structure for the treatment of spondylolisthesis. Background Art

[0002] Spondylolisthesis, medically known as vertebral slippage (Spondylolisthesis), refers to the forward or backward slippage of one vertebral body relative to the vertebral body below. This condition usually occurs in the lumbar region, but it may also affect the cervical spine or other parts.

[0003] The reduction of spondylolisthesis (Spondylolisthesis) generally refers to repositioning the slipped vertebral body to the correct position in order to restore the normal spinal anatomical structure. However, once a vertebral body has slipped, especially when a certain degree of slippage has formed, it is very difficult to completely reduce it because the surrounding soft tissues (such as muscles and ligaments) and bone structures may have adapted to the new position. In addition, spondylolisthesis is often accompanied by fractures of the pedicles or degeneration of the intervertebral discs, making self-reduction unlikely.

[0004] If spondylolisthesis (lumbar spondylolisthesis) is severe and not treated in a timely manner, it may lead to a series of serious consequences. These consequences not only affect the patient's quality of life but may also have long-term adverse effects on health. The possible consequences are as follows: 1. Nerve root compression: This is one of the most common consequences. As the degree of spondylolisthesis increases, it may cause nerve root compression, resulting in numbness, weakness, muscle atrophy in the lower limbs, and even symptoms such as lower limb pain and difficulty walking. 2. Intermittent claudication: Due to nerve compression or lumbar spinal stenosis, patients may experience leg pain or weakness when walking, forcing them to stop and rest frequently, which is called intermittent claudication. 3. Sciatica: Spondylolisthesis can affect the sciatic nerve, causing radiating pain, numbness, and tingling sensations extending from the waist to the legs. 4. Increased lumbar lordosis: Patients may present with a forward protrusion of the lumbar curve, accompanied by a significant posterior protrusion of the buttocks and an unsteady gait when walking. 5. Defecation and urination dysfunction: In very severe cases, spondylolisthesis may damage the nerves controlling the bladder and rectum, resulting in the patient's inability to control defecation and urination normally. 6. Risk of paralysis: One of the most serious consequences is the possible paralysis of both lower limbs, especially when the slippage severely affects the spinal cord or nerve roots.

[0005] For mild spondylolisthesis, non-surgical treatments such as rest, physical therapy, anti-inflammatory drugs, and core muscle strengthening training can relieve symptoms, but they usually cannot reduce the vertebral body. For moderate to severe spondylolisthesis, especially when accompanied by persistent pain, nerve compression symptoms, or spinal instability, surgical treatment may need to be considered.

[0006] Currently, for spondylolisthesis, spinal fusion surgery is used to treat it, which is one of the most commonly used treatment methods. The purpose is to stabilize the affected area and prevent further slippage. During this process, doctors will use autologous bone graft materials, synthetic materials or other biocompatible materials to fill between two or more vertebral bodies to promote them to grow together to form a whole. In order to increase stability, in some cases, internal fixation devices such as metal screws and rods are also used in combination.

[0007] For example, Chinese Patent Publication No. CN217090867U discloses a vertebral body lifting and reduction fixation device, which includes a lifting screw, a nut, a connecting rod and a pedicle screw. The lifting screw includes a first threaded section for implanting into the slipped vertebra and a second threaded section for implementing lifting. One end of the second threaded section close to the first threaded section is provided with an intermediate block protruding radially from the lifting screw; the nut is used to cooperate with the second threaded section to implement lifting; the connecting rod has a through hole for sleeving the lifting screw; the pedicle screw includes a screw body for implanting into the normal vertebra near the slipped vertebra and a connector for connecting the connecting rod.

[0008] However, currently, once a situation of pedicle fracture occurs in spondylolisthesis, it is relatively difficult for the nail / rod / bar system adopted from the posterior approach to achieve the corresponding fixation action. Considering factors such as the general age and bone density of patients in the case of pedicle fracture, it is not suitable to use the method of pedicle screw fixation. For pedicle fracture, currently, the conventional method is to perform spinal fixation by posterior spinal fusion. Summary of the Invention

[0009] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and avoid the following problems that may be caused by spinal fusion: 1. Local stiffness: The fused area will lose its normal motor function, resulting in a reduced range of motion in this area. 2. Adjacent segment disease: In the long term, the adjacent unfused intervertebral discs may degenerate faster due to bearing greater pressure, which is called adjacent segment disease (ASD). 3. Fusion failure: Not all fusions can be successful. Sometimes, the bones cannot heal completely, resulting in the formation of a false joint, which may require reoperation.

[0010] The present invention aims to avoid situations such as local stiffness and adjacent segment disease after treatment. Secondly, the treatment method of the present invention can be combined with methods such as bone grafting to repair the pedicle.

[0011] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0012] A belt structure for treating spondylolisthesis, the belt structure is in an H shape, including two pairs of upper and lower stay ropes and a stay rope connecting part surrounding the spine; the ends of the two pairs of stay ropes are respectively connected to the upper spine and the lower spine of the spondylolisthetic spine, and the belt structure applies a pulling force to the upper spine and the lower spine through the stay ropes so as to hold the spondylolisthetic spine. The belt can adopt currently mature artificial ligament materials, degradable or non-degradable materials.

[0013] Optionally, the stay rope connecting part is a belt or a mesh belt.

[0014] Optionally, the tail ends of the stay ropes are fixed to the transverse processes on both sides of the upper spine and the lower spine of the spondylolisthetic spine by steel nails.

[0015] Optionally, the tail ends of the stay ropes are sleeved on the transverse processes on both sides of the upper spine and the lower spine of the spondylolisthetic spine by a noose.

[0016] Optionally, the tail ends of the stay ropes are fixed to the spinous processes of the upper spine and the lower spine of the spondylolisthetic spine by steel nails.

[0017] Optionally, the tail ends of the stay ropes are sleeved on the spinous processes of the upper spine and the lower spine of the spondylolisthetic spine by a noose.

[0018] Generally speaking, when using the steel nail fixation method, there is a situation of pedicle fracture. In this case, it is difficult to find excellent stress points on the human spine. The steel nail fixation position can be selected at appropriate positions on the upper spine and the lower spine of the spondylolisthetic spine, and try to avoid parts such as blood vessels and nerve roots.

[0019] Preferably, the belt structure adopts a controllable degradation material. The externally controllable degradable material described in the present invention is a special type of material. They can change their physical properties under the action of external stimuli such as temperature, light, pH value, magnetic field or electric field, and can gradually decompose and be absorbed by the environment or organisms under specific conditions.

[0020] Preferably, the controllable degradation material is a Fe 3 O 4 3O4-PDLA-PEG copolymer. The Fe3O4-PDLA-PEG copolymer adopted in the present invention can generate heat through hysteresis loss 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 the surrounding polymer to undergo a phase change or degradation, achieving the purpose of controllable degradation.

[0021] Preferably, the Fe₃O₄ 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.

[0022] According to the specific conditions of each patient, the pulling force and structure of the mesh belt are evaluated and selected individually. Finite element analysis (FEA) can be used for more detailed mechanical simulation. This technology can create a digital model of the human spine and simulate different correction strategies and their effects. For example, the NSYS Workbench software (a widely used multi-physics simulation platform) can be used. The process is as follows: clarify the specific purpose you hope to achieve through FEA (the stress distribution of the spine under different correction forces, determining the pulling force of the mesh belt structure), import the 3D body model obtained by the Materialise MimicsinPrint software into NSYS Workbench, define the boundary conditions and constraints, determine the fixed points and other constraints in the model, and simulate the state of the human body in natural standing. Define the material properties, set the material characteristics of bones, intervertebral discs and other soft tissues, such as elastic modulus, Poisson's ratio, non-linear behavior, etc., set the material, 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 NSYS Workbench to ensure that the mesh quality is high enough to capture important mechanical details while maintaining computational efficiency. Note that the mesh density should be appropriately increased in areas with stress concentration or large deformation. 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 situation of spondylolisthesis in postures such as walking, lying down, sitting, and bending. Solver configuration and operation, select the appropriate solver type (static, dynamic or quasi-static solver), consider using a dynamic solver according to the spondylolisthesis project recommendations to ensure that the solver can reach a stable solution within a reasonable time, and the simulation can obtain the pulling force information required for the mesh structure. Finally, select the required mesh belt structure according to the simulation results.

[0023] The beneficial effects of the present invention are as follows: The mesh belt structure of the present invention provides another solution for patients who are not suitable for the existing steel plate and steel nail reduction methods. The ends of the mesh belt can be fixed with steel nails. For patients with relatively low bone density, such as the elderly, the mesh belt structure connected by a lasso of the present invention can be used. After the operation, methods such as bone transplantation can be combined with the treatment method of the present invention to repair the pedicle. Using the mesh belt structure of the present invention can avoid stiffness after the operation and retain a certain range of motion of the spine. The surgical process of the present invention causes less damage to bone tissue compared to existing surgeries and can achieve minimally invasive surgery in certain specific situations. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a mesh belt structure with a connecting part;

[0025] Figure 2 It is a schematic diagram of a mesh belt structure of a mesh belt connecting part;

[0026] Figure 3 It is a schematic diagram of Embodiment 1;

[0027] Figure 4 It is a schematic diagram of Embodiment 2;

[0028] Figure 5 It is a schematic diagram of Embodiment 3;

[0029] Names of the reference numerals in the figure: 1 - connecting part, 2 - drawstring, 3 - lasso, 4 - steel nail, 5 - transverse process, 6 - spinous process. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The mesh belt structure adopted by the present invention can be applied to anterior spinal surgery, lateral spinal surgery or posterior spinal surgery. Generally speaking, posterior spinal surgery is safer.

[0031] The following further elaborates on the present invention in combination with 3 embodiments. The mesh belt structures of the embodiments are as Figure 1 shown. The mesh belt structure is in the shape of an H, including two pairs of upper and lower drawstrings 2 and a drawstring connecting part 1 surrounding a belt of the spine. The ends of the two pairs of drawstrings 2 are respectively connected to the upper spine and the lower spine of the spine with slippage. The mesh belt structure applies a pulling force to the upper spine and the lower spine through the drawstrings 2 to hold the spine with slippage. The mesh belt adopts iron oxide nanoparticles - PDLA - PEG copolymer.

[0032] Embodiment 1

[0033] As Figure 3As shown in the figure, the end loop of the pull rope 2 is sleeved on the steel nail 4 driven into the transverse process 5, tied tightly with a thread, and the excess rope end is cut off. The laying method is as follows: First, drive in the steel nail 4, sleeve the end loop of a pull rope 2 on the steel nail 4 on one side, tie it tightly with a thread, and then sleeve the corresponding end of this pull rope 2 on the steel nail 4 on the other side in the same way to form a closed loop. Then, use a tension pliers with a certain poundage to pull the end until the predetermined tensile poundage, and then tie it tightly with a thread; the other pair of pull ropes 2 is processed in the same way.

[0034] Embodiment 2

[0035] As Figure 4 shown in the figure, the end of the pull rope 2 is sleeved on the transverse process 5 through the lasso 3, tied tightly with a thread, and the excess rope end is cut off. The laying method is as follows: First, pass the end of a pull rope 2 around the transverse process 5 on one side through a crochet hook to form a closed loop and tie it tightly with a thread. Then, pass the corresponding end of this pull rope 2 around the transverse process 5 on the opposite side in the same way to form a closed loop. Then, use a tension pliers with a certain poundage to pull the end until the predetermined tensile poundage, and then tie it tightly with a thread; the other pair of pull ropes 2 is processed in the same way.

[0036] Embodiment 3

[0037] As Figure 5 shown in the figure, the end of the pull rope 2 is sleeved on the spinous process 6 through the lasso 3, tied tightly with a thread, and the excess rope end is cut off. The laying method is similar to that of Embodiment 2.

[0038] In order to perform more precise minimally invasive surgery, intraoperative fluorescence imaging technology is used to observe the blood vessels and lymphatic systems in the spinal region before the surgery. And intraoperative ultrasound technology uses high-frequency sound waves to generate images of internal organs and structures, providing sufficient and safe preparations for the surgery, determining the surgical position, and adopting a suitable mesh belt structure.

[0039] During the surgical procedure, corresponding intraoperative nerve monitoring methods need to be adopted. This method monitors the function of the nervous system through electrophysiological signals, such as brainstem auditory evoked potential (BAEP), somatosensory evoked potential (SSEP), and motor evoked potential (MEP), to avoid damaging the nerve roots and the spinal nervous system.

[0040] The surgical procedure is as follows: First, place the mesh belt structure into the catheter. Generally, since the anterior longitudinal ligament in front of the spine is some important tissues and organs of the human body. Specifically: in the cervical and thoracic vertebrae parts, in front of the anterior longitudinal ligament are mainly the esophagus, trachea, and related soft tissues. In the thoracic region, there are also important blood vessels such as the thoracic aorta in front of the anterior longitudinal ligament. In the lumbar part, in front of the anterior longitudinal ligament is close to large blood vessels such as the abdominal aorta and inferior vena cava, as well as abdominal organs such as the pancreas and small intestine. Generally, there is a "depression" in the central part of the spine, and this position is generally a relatively weak part of some connective tissues. During the operation, it can be considered to place the mesh belt structure through this position. Secondly, pass the catheter through the above-mentioned weak connective tissue part from the left side of the displaced spine to the right side of the displaced spine. The catheter can extend out from the right side. Take out the right pull rope of the mesh belt structure from the catheter and perform the right fixation operation. Then withdraw the catheter from the left side of the displaced spine and take out the left pull rope of the mesh belt structure from the catheter to perform the left fixation operation.

[0041] After the displaced spine is reduced, it can be connected to the fractured pedicle, and further measures such as bone graft repair can be taken for treatment.

[0042] 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. A mesh belt structure for treating spondylolisthesis, characterized in that: The mesh belt structure is H-shaped, including two pairs of upper and lower pull ropes and a pull rope connecting part surrounding the spine; the rope ends of the two pairs of pull ropes are respectively connected to the upper spine and the lower spine where the spinal column has slipped, and the mesh belt structure applies tension to the upper spine and the lower spine through the pull ropes to pull the spinal column that has slipped.

2. The mesh belt structure for treating spondylolisthesis according to claim 1, characterized in that: The drawstring connection portion is a belt or a mesh belt.

3. The mesh belt structure for treating spondylolisthesis according to claim 2, characterized in that: The tail ends of the pull ropes are fixed to the transverse processes on both sides of the upper and lower vertebrae where the spinal column slips by steel nails.

4. The mesh belt structure for treating spondylolisthesis according to claim 2, characterized in that: The tail end of the pull rope is sleeved on the transverse processes on both sides of the upper and lower vertebrae where the spinal column has slipped through a lasso.

5. The mesh belt structure for treating spondylolisthesis according to claim 2, characterized in that: The tail ends of the pull ropes are fixed to the spinous processes of the upper and lower vertebrae where the spinal column slips by steel nails.

6. The mesh belt structure for treating spondylolisthesis according to claim 2, characterized in that: The tail end of the pull rope is sleeved on the spinous process positions of the upper and lower vertebrae where the spinal column slips through a lasso.

7. The mesh belt structure for treating spondylolisthesis according to claim 2, characterized in that: The mesh belt structure adopts controllable degradation material.

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

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