RU2767279C1 - Method for kyphotic deformity correction in thoracic spine in growing dogs - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to veterinary science, and can be used for correction of kyphotic deformity in thoracic spine in growing dogs. In the course of kyphotic deformity correction, in the area of deformity a transthoracic approach to the vertebral bodies is performed with exposing their ventro-lateral surface. An intervertebral disc is fenestrated with a surgical cutter. At the level of deformity, one multiaxial screw is introduced into the vertebral bodies in the deformation zone, as well as one multiaxial screw is introduced into the thoracic vertebral bodies cephalad and caudal to the deformation. Screws are delivered bicortically. Then the fixing bar is delivered, distraction is performed until the deformation area is straightened, and the bar is fixed in screws. Then one more multiaxial screw is inserted into the thoracic vertebrae cranially and caudally to the installed structure and fixed with a bar.

EFFECT: method provides reducing iatrogenic risks of spinal cord injury in the process of performing the required vertebral distraction by setting the second level of stability.

1 cl, 12 dwg

Description

The invention relates to the stabilization of the spinal column of dogs with kyphotic deformity and can be used to reduce the iatrogenic risks of spinal cord injury and increase the strength of the structure in the process of performing the necessary distraction of the vertebrae to correct kyphotic deformity.

From the prior art, a solution is known according to the patent RU 170604 U, published: 05/02/2017.? which describes a medical instrument for temporary stabilization of the spinal column when correcting its deformity, which consists of two rods of a circular cross section, the rods are arranged in series, the adjacent ends of the rods are connected by means of an axial hinge, transpedicular screws are installed on the rods, the transpedicular screws have a tuning fork head and are installed with the possibility of fixing the position with locking screws, the connected end of the first rod is made in the form of a fork, the connected end of the second rod is made in the form of an eye, the second rod is inserted into the fork of the first rod with an eye and connected to it by an axis-screw with the possibility of fixing the mutual position.

In this analog, the beam for the transpeds is made with a hinge, which increases the risk of instability. It is important to add to this that the hinge is not required for transthoracic fixation. The main drawback is that the transpeds and the beam with a hinge are installed dorsally, which does not provide the necessary strength.

The claimed invention uses a simple beam that increases strength. The prior art solution is known according to the patent RU 2159587, publ.: 27.11.2000. It describes a method for correcting spinal deformity by wedge-shaped resection of the anterior and posterior sections of the spine along the arc and correcting the deformity using an endocorrector, characterized in that wedge-shaped deformed vertebral bodies are compressed along the arc with a change in their shape.

This method has many differences from the claimed invention, which will cause difficulties and risks of iatrogenic damage. Firstly, 2 stages of the operation are required, followed by rehabilitation, which is not acceptable for animals that have a greater load on the spinal column, and in the early postoperative period they are very active and any temporary structures may break. Secondly, as in the previous analogues, the design is installed dorsally and the distraction is carried out behind the vertebral arch, which makes it impossible to use this method in small breeds of dogs, and in large ones it is extremely risky. In contrast to this method, the claimed invention involves ventrolateral fixation and distraction of the vertebral bodies. Thirdly, the analog has external immobilizing structures, which carries more risks of instability, infection of wounds.

The prior art solution is known according to the patent RU 2297192, publ.: 20.04.2007. EFFECT: invention provides reduction of invasiveness and laboriousness of using the device during treatment according to Luque's method while maintaining all its advantages. The device includes a prefabricated structure of fixing elements located one below the other, and a pair of rods or wires, one of which connects the fixing elements located along one longitudinal side of the prefabricated structure, and the other - along the other. A pair of rods or wires are interconnected by at least a pair of crossbars. Each locking element contains a blocky body, a hook and a gripping device. The lumpy body is mounted on a rod or wire with the possibility of rotation around its longitudinal axis, moving along and fixing in the occupied position. The hook is made out of the block-like body, and its first contact surface to ensure the process of correction and stabilization is formed by the inner side of the initial part of the hook, coming out of the block-like body and bending under it, the second contact surface to ensure the correction and stabilization process is formed by the surface of the hook end part bending upwards . The first and second contact surfaces to ensure the process of correction and stabilization are located passing into each other. The gripping means is made pointed so that it can be located in the gripping position and extended into the space between the first and second contact surfaces to ensure the correction and stabilization process.

This analogue is widely applicable in medicine in the treatment of people. But for animals, this method is considered very traumatic and requires the implant to be inserted into the spinal canal, which increases the risk of iatrogenic spinal cord injury many times over and can lead to disability in the dog.

Also, all screws pass through the vertebral arches, and this method of screw placement cannot be performed adequately in dogs (there are risks of getting into the spinal canal and injuring the spinal cord or nerve, and there is also a risk of fracture of the arch).

And just like other analogues, it is carried out dorsally.

In contrast to this method, the claimed invention allows to achieve a stable result without injuring the arches and not getting into the spinal canal at all.

The prior art solution is known according to patent RU 2392888, publ.: 27.06.2010. The method is carried out in two stages: posterior percutaneous transpedicular osteosynthesis with an external fixator, then, after a staged correction of the spinal column deformity, the second stage is performed - replacement of the external transpedicular fixator with a submersible one in the corrected position. The method allows to restore the physiological curves of the spine with minimal tissue trauma.

In this analogue, the correction of the deformity takes place in 2 stages (stage 1 - installation of an external fixation device, which cannot be done in dogs; stage 2 - transpeds are placed and also dorsally).

The closest analogue is the solution according to patent RU 2085145, publ.: 27.07.1997., which describes a device for the surgical treatment of spinal deformities. It contains a rod with holes at the ends, upper and lower attachment points to the spine installed at the ends of the rod in the form of combs with racks, connected in pairs by means of studs and nuts placed in the racks, while the pin of the upper attachment point is connected to the upper end of the rod by means of an installed in the hole of the rod of a screw with a head having a hole for a stud and nuts, and the stud of the lower attachment point is placed in the hole of the lower end of the rod by means of nuts. The rod is made in the form of a plate with a cutout at the lower end, a body with a shaped hole and a spring, and the end of the plate and the spring are installed in the body with the possibility of placing the spring in the plate cutout.

This analogue has the same technical problems as the previous one - the structure is installed dorsally.

In addition, this design is technically complex, which lengthens the operation time, and it is quite voluminous (therefore, it cannot be used in small dogs).

Since animals are more mobile and nimble, this design is not applicable to them, since it has a high risk of failure.

All described analogs were previously used in veterinary neurosurgery, some of them have quite good results. But in the treatment of kyphotic deformity, they will not be able to solve the main problem - to correct the kyphotic angle.

Each of these analogues provides us with the option of dorsal or dorso-lateral implant placement. This causes a number of difficulties: 1) Dorsal laminectomy is required, which obviously increases the risk of iatrogenic spinal cord injury;

2) All deformities are kyphotic in animals (in the thoracic spine) and from the dorsal approach, it is physically very difficult to insert the screws adequately and requires a sufficiently voluminous approach, and the screw is carried out dorso-laterally, which indicates a high risk of the screw falling into the spinal canal, causing compression spinal cord. This is due to the anatomical features of dogs, in which the bodies of the thoracic vertebrae are not as wide as in humans and, as a rule, in dogs with kyphosis, they have aplasia of the bodies, which also creates an additional difficulty in placing implants.

3) It is rather difficult to correct the angle of kyphosis, and in some cases it is not possible. It is also very difficult to visualize the degree of kyphosis correction intraoperatively.

The objective of the invention is to eliminate these technical problems specific to known analogues.

The technical result is that it does not allow iatrogenic damage to the spinal cord, reduces the risks of iatrogenic damage to the spinal cord, increases the strength of the structure, its reliability. In addition, the claimed method is more convenient for surgeons.

The specified technical result is achieved due to the fact that the method for correcting kyphotic deformity in the thoracic spine in growing dogs is claimed, characterized by the institution of a fixing beam in screws inserted into the vertebral bodies at the level of kyphosis, characterized in that access to the vertebral bodies is done transthoracically in the area deformities on the right, with exposure of the ventrolateral surface; then, the intervertebral disc is fenestrated with a surgical cutter at the level of the deformity, followed by insertion of one multiaxial screw into each vertebral body, ventrolaterally, cranially and caudally to the deformity, and the screws are inserted bicartically; after that, a fixing bar is inserted, then with a vertebral distractor, resting between the screws, distraction is carried out at the required angle until the deformity area is straightened, after which the bar is fixed in the screws; then one more multiaxial screw is inserted into the thoracic vertebrae and fixed with the 2nd beam, thus we get 2 levels of stability and we achieve greater structural strength.

Brief description of the drawings

Figure 1 is an x-ray of a dog before surgery showing the access area.

Fig. 2 in the image is an x-ray of the same dog after surgery with a fixation bar in place.

On FIG. 3 shows a skin section.

On FIG. 4 shows a thoracotomy dissection of the latissimus dorsi.

On FIG. 5 shows a thoracotomy dissection of the intercostal muscles.

On FIG. 6 shows the dissection of the muscles, the skeletonization of the vertebral bodies.

On FIG. 7 shows fenestration.

On FIG. 8 shows the stage of screw insertion.

On FIG. 9 shows the stage of preparation for the distraction.

On FIG. 10 shows the stage of guiding the distractor to the multiaxial screws.

On FIG. 11 shows the distraction and anchoring of the beam.

On FIG. 12 shows the fixed beam structure installed.

Implementation of the invention

The claimed method for correcting kyphotic deformity in the thoracic spine in growing dogs is characterized, as in the prototype, by the introduction of a fixing beam in screws inserted into the body of the intervertebral disc.

What is new is that access to the vertebral bodies is done transthoracically in the deformity area on the right, with exposure of the ventrolateral surface. Next, fenestration of the intervertebral discs is performed with a surgical cutter at the level of the deformity, followed by insertion of one multiaxial screw into each body of the intervertebral disc cranial and caudal to the deformity, the screws being inserted bicartically. After that, a fixing bar is inserted, then with a vertebral distractor, resting between the screws, distraction is carried out to the required angle until the deformity area is straightened, after which the bar is fixed in the screws. Then one more multiaxial screw is inserted into the thoracic vertebrae and fixed with a bar.

This method completely changes the approach to the technical problems of the known analogues described above. Access to the vertebral bodies is done transthoracically, exposing the ventrolateral surface. At the same time, the kyphosis point is perfectly visualized, and we see the changed vertebrae. To facilitate the correction of curved vertebrae, this access is used to fenestrate the intervertebral disc at the point of greatest deformation. Due to the introduction of screws ventro-laterally, it is possible to perfectly visualize the angle of passage of the screw, which reduces the risk of screw insertion into the spinal canal. In addition, this way of passing the screw is more durable because the screws are completely immersed in the body.

At the same time, access to the spinal cord is not required, which makes the operation less risky and reduces the iatrogenic risk of spinal cord injury.

Also, in the claimed method, two levels of stability are formed and, which is very important, it is easy to visualize how much we are distracting the vertebrae. And since we can easily control the angle of screw insertion, we also reduce the risk of iatrogenic spinal cord injury.

The method requires multiaxial screws and a fixing beam. The operation according to the claimed method is carried out as follows.

The patient is placed on the operating table on the left side. A linear right-sided access to the chest is made (see Fig. 1). Skin incision approximately between the sixth intercostal space (see Fig. 3). In this case, the incision may slightly shift cranial or caudal, depending on the level of deformation of the spinal column.

A right-sided thoracotomy is performed by dissection of the latissimus stairus and intercostal muscles (see Fig. 4).

The ribs are expanded and retracted with a rib expander (see Fig. 5).

The area of deformation is visualized, the vertebral bodies are skeletonized (see Fig. 6).

Next, fenestration of the intervertebral discs is carried out with a surgical cutter at the level of deformation (see Fig.7). For example, if the deformity is at the level of 6-7 thoracic vertebrae, then we fenestrate the intervertebral disc between these bodies.

The next step is to insert one multiaxial screw into each body of the thoracic vertebra cranial and caudal to the deformity, in this example in the 5th, 6th, 7th, 8th thoracic vertebrae (see Fig. 8). In this case, the screws are inserted bicartically.

Then, a fixing beam is inserted into the system of multiaxial screws (see Fig. 9).

Next, using a vertebral distractor, resting between the screws (in this example, between 5 and 8 screws), distraction is carried out to the required angle so that the deformity area straightens out (see Fig. 10). After it is straightened, the beam is fixed in screws (see Fig. 11).

After that, one more multiaxial screw is inserted into the thoracic vertebrae (in this example, into the 4th and 9th thoracic vertebrae) and fixed with a bar.

Thus, two levels of stability are formed (see Fig. 12).

Then, lavage of the surgical wound is carried out with a sterile isotonic solution, layer-by-layer suturing of the surgical wound with absorbable threads, for example, monofilament. This completes the operation.

The result of the operation is distraction and correction of the cophotic deformity of the spinal column, decompression of the spinal cord in the deformity area.

On FIG. Figure 2 shows a post-operative x-ray of a dog showing that during this operation we corrected the deformity with multi-axial screws and fixation bars. The upper level of the screws and beams corrected the deformity and allowed for the necessary distraction and alignment of the vertebrae. The lower level of the screws of the beams gave reinforcement to the structure.

The essence of the described method lies in the fact that the first level of screw insertion into the nearest thoracic vertebrae of the spinal column allows you to perform the necessary distraction of the spinal column to correct the Cobb angle and straighten the spinal column. And the second level of stability is that we insert additional multiaxial screws into the vertebral bodies of the thoracic region and fix them with a beam to increase the strength of the structure.

Due to this, a more controlled distraction of the spinal column is carried out, and it is more durable with two levels of stability.

The claimed method is currently the only method of surgical treatment of kyphotic deformity of the spinal column in dogs, which gives excellent results.

Practice has shown that it is convenient for surgeons. So, if earlier cortical screws and bone cement were used to stabilize the spinal column of dogs with kyphotic deformity. At the same time, the bone cement, in turn, did not always withstand the loads, and the structure collapsed, became unstable, and the patients again developed a neurological deficit.

And since instead of implants, multiaxial screws are carried out in two levels, we increase the strength of the structure, the method becomes more reliable, and the operation itself is more convenient for surgeons.

Claims (1)

A method for correcting kyphotic deformity in the thoracic spine in dogs, characterized by inserting a fixing beam in multiaxial screws inserted into the bodies of the thoracic vertebrae, characterized in that during the correction of kyphotic deformity in the deformity area, transthoracic access to the vertebral bodies is performed, exposing their ventro- lateral surface, fenestration of the intervertebral disc with a surgical cutter; at the level of deformity, one multiaxial screw is inserted into the vertebral bodies in the deformity zone, as well as one multiaxial screw into the bodies of the thoracic vertebrae cranial and caudal to the deformity; screws are carried out bicortically; then a fixing beam is carried out, distraction is carried out until the deformation area is straightened and the beam is fixed in screws; then, one more multiaxial screw is inserted into the thoracic vertebrae cranial and caudal to the installed structure and fixed with a beam.

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