RU22611U1 - DEVICE FOR FIXING SPINAL MOTOR SEGMENTS OF EXPERIMENTAL ANIMAL IN SPONDYLODESIS - Google Patents

Description

Adaptation of the fixation of the posterior motor segments of the experimental animal during sonondylosis

The utility model relates to medicine, namely

to experimental vertebrology, and can be used to model spinal fusion during experimental studies of the biological properties of bone and artificial implants, as well as the reparative properties of bone tissue, in particular, to assess the suitability of implants for use in anterior and posterior fusion.

Closest to the declared decision on sovokoyanO € rg1g

signs is a device for fixing pfunochnyh motor segments of an experimental animal, as

which dog 1 is used. The device adopted as a prototype consists of a fixation unit with attachment elements for vertebral retainers (knitting needles). At the same time, the fixation unit is made in the form of a special arc repeating the contours of the transverse cut of the dog’s body in the region of the lumbar spine, on the surface of which 12-18 attachment elements (fixation points) are located.

IPC A61 B 17/56

 UL V)

Oh, Fixture prototype 1 provides a rigid fixation of the vertebral bodies, which allows it to be used in modeling fusion with implants with different biological properties (including with different mechanical strength). However, the prototype device does not allow to obtain the technical result achieved when using the claimed device, for the following reasons. The design features of the fixation unit (arc) make it possible to use the device in question only on the lumbar spine of an experimental animal (dog), which, in turn, limits the localization of possible implantation zones (when modeling spinal fusion using a prototype device for fixation) to the lumbar spine , spinal fracture using a prototype device is actually the so-called "spoke method, which requires fixation tion segment over its relatively large or a relatively large number of segments. In the description of the device of the prototype 1 it is indicated that to ensure stable fixation should be recorded as a minimum) 2-3 vertebrae from each. sides of the operated segment (i.e., only 4-6 vertebrae), with at least three knitting needles inserted into each vertebra. This leads to a relatively high probability of destruction of the structures of fixed vertebrates (especially with their small sizes). On the other hand, 1 is known that the implementation of surgical interventions on the lumbar spine is complicated, in particular, by the proximity of the main (aorta and inferior vena cava) and segmental vessels, the presence of the spinal cord in the canapes. In this regard, such fixation is associated with a high risk of damage to organs of the retroperitoneal space (aorta, kidneys, ureters), as well as the spinal cord, as the needle is carried out blindly in the immediate vicinity of these vital anatomical organs. Damage to the spinal cord, in turn, leads to the development of neurological disorders in the form of paresis of the lower extremities. Left-sided lumbotomic access to vertebral bodies, which is usually used to model spinal fusion in the lumbar spine of dogs, further increases the likelihood of damage to the organs of the retroperitoneal space, which can lead to death of the operation. The introduction of a large number of vertebral fixators, necessary for fixation with the help of a prototype device, increases the likelihood of developing infectious complications (in particular, spoke osteomyelitis), as well as lysis of bone tissue around the fixators. In addition, setting a large number of knitting needles significantly increases the duration of the operation. The implementation of spinal fusion on the lumbar spine of experimental animals requires the use of prolonged intubation anesthesia, muscle relaxants and parenteral administration of blood substitutes in the intraoperative and postoperative periods, which greatly complicates the design of the experiment and .1P1 protects its duration. In addition, as a result of deep anesthesia and the severity of the operation (massive trauma), experimental animals usually experience postoperative agitation, which has a negative effect on the course of the postoperative period, prolonging the recovery time. And finally, the prototype device is characterized by the technical complexity of manufacturing, due to the need to perform special arcs of a certain shape and size. The above reasons (increased likelihood of destruction of vertebral structures

small size; increasing the technical complexity of manufacturing devices with significantly lower parameters, etc.) almost completely exclude the possibility of using the prototype device in small experimental animals, in particular in rats.

The objective of the utility model is to create a device for fixing the vertebral motor segments of an experimental animal during spinal fusion, providing the ability to simulate anteroposterior spinal fusion using implants with various biological properties, while eliminating the possibility of damage to vital anatomical organs and structures of the spine in the fixation zone, due to the stability of the location fixed vertebrae in the process of bone block formation as a friend relative to dr ha and relatively imsh1antata, while minimizing the values of characteristic parameters of fixation.

The problem is solved in that in the device for fixing the vertebral motor segments of the experimental animal during spinal fusion, containing the fixation unit, with the attachment elements of the vertebral retainers placed on it, according to the useful mode. 1sh fixation unit is made in the form of an elongated geometric body having an internal through cavity, located along the central axis of the geometric body. The fastening elements of the vertebral retainers are made in the form of at least pairs of through coaxial channels under the vertebral retainers located on the lateral surface of the geometric body. Moreover, the channels for the vertebral retainers in each pair are made identical to each other in cross-sectional diameters and placed on the side surface of the geometric body in such a way that the axis of each channel pair is located in a plane parallel to the frontal plane of the projections, at an angle of 40-50 ° to frontal axis and intersects the central axis of the geometric body, and the inlet channels of different pairs are placed on the side surface of the geometric body longitudinally relative to its central axis. The optimal length of the elongated geometrical body is 0.25-0.33 of the tail length of the experimental animal. The most effective is a device made in such a way that the profile of the internal through cavity of an elongated geometric body corresponds to the profile of the outer surface of the latter. The optimal diameter of the circle inscribed in the geometric figure, which is a cross section of the inner through cavity of the elongated geometric body, is 1.8-2.2 of the outer diameter of the tail of the experimental animal in the region of the third caudal vertebra. It is most effective when a through inspection hole is made on the lateral surface of an elongated geometric body. It is optimal to perform a fixation block in the form of a straight regular hollow hexagonal prism, the length of the lateral edge of which is 0.25-0.33 of the tail length of the experimental animal, and the diameter of the O1 fusion inscribed in the polygon, which is a cross section of the inner cavity of the prism, is 1, 8-2.2 of the outer diameter of the tail of the experimental animal in the region of the third caudal vertebra. Moreover, it is most effective when the through channels for vertebrae fixators are placed on four pairwise parallel lateral faces of the prism, for example, 1-3 channels on each of these faces, and on each of two mutually parallel side faces these channels are made pairwise coaxial, the axis of each pairs of channels crosses the longitudinal axis

symmetries of each of the mutually parallel faces on which the channels of a given bunk are located, and the centers of the inlet holes of the channels placed on each of the faces are located on the longitudinal axis of symmetry of this face. Optimal is the placement of channels under the vertebral retainers, comprising different pairs, on adjacent lateral faces of the prism. The most effective is the implementation of a through inspection hole on the side of the prism, which does not contain channels for vertebrae retainers.

To select the optimal channel placement under the clips

vertebrae on the lateral surface of the fixation unit, as well as optimal

fixation block forms 2 series of experiments were carried out using

13 adaptation options. In all series of experiments produced

anteroposterior fusion of cortical allografts from

adults (produced by the Russian Research

Institute of Traumatology and Orthopedics. R. Vredena, laboratories

preparation and preservation of tissues). Experimental research

performed on sexually mature laboratory rats. Each option

the devices were tested on a group of animals consisting of 5 individuals.

In both series, a vertebral fixator was used

injection needle with a cross-sectional diameter of 1 mm. Term

observation of experimental animals for 14 days. Distribution

animals by series and gr) spam looked as follows:

I series of experiments - a device made in the form of a direct circular

hollow cylinder, on the side of which

there was a through inspection hole, as well as pairs

end-to-end coaxial channels under the vertebral retainers,

arranged so that their axes crossing the central axis In all of the 1FYSY samples so that they are fixed immediately, the second series of experiments in planes parallel to the frontal plane of the projections, at angles to the frontal axis, comprising 20, 30, 40, 50, 60, 70 to the front axis (groups No. 1-6); in the sagittal plane at angles of 40 and 50 to the sagittal axis (groups 7, 8); in a horizontal plane at angles of 40 and 50 to the horizontal axis (groups nos. 9,10). In series I, the fixture was mounted on the tail at a time to provide a given plane and angle of placement of the through inspection hole above the surgical wound (operating positions). A device made in the form of a straight regular hollow hexagonal prism with various placement of through channels for vertebral retainers and a through inspection hole: through channels for vertebral retainers were located on four pairwise parallel lateral faces (3 channels on each face), and the centers of the channel inlet openings each of the faces was on the longitudinal axis of symmetry of this face; on each of the two mutually parallel faces, the specified channels were made coaxial and identical in cross-sectional diameters to the corresponding channels placed on the other face, and the axis of each pair of channels crossed the central axis of the Fixture was installed on the side faces pr placed from to the side faces from the prism. The through inspection hole was on the verge that did not contain channels for vertebral retainers (group No. 11); through channels for vertebral retainers were located on two mutually parallel lateral faces of the prism (on each side there are 2 channels, pairwise coaxial and identical in cross-sectional diameter); the centers of the inlet channels on each of the faces were located on the longitudinal axis of symmetry of this face; the axis of each channel pair crossed the central axis of the prism. A through inspection hole was located on one of the faces containing channels under the vertebral retainers (group No. 12); through channels for vertebral retainers were located on two side ribs of adjacent pairwise parallel side faces of the prism (on each edge there are 6 channels pairwise coaxial and identical in cross-sectional diameters). The through inspection hole was located on one of the lateral faces, the edges of which did not contain channels (group No. 13). in the variant used in group No. I, the tail of the rat in such a way that two non-adjacent isms containing channels under the vertebral retainers, the lateral sides of the tail, and two other non-adjacent by-pass channels parallel to the specified ones) / / -VJA) -tvi fy

1(

h to the sides, from the Hungarian-lateral sides of the tail, and the through-hole was located above the surgical wound (working position). The device in the variant used in group No. 12 was mounted on the tail of the rat so that the lateral faces containing channels under the vertebral retainers were parallel to the plane of the operating table (in the horizontal plane), and the through-hole was directly above the surgical wound (working position ) The device in the variant used in group No. 13 was mounted on the tail of the rat so that in each pair of adjacent lateral faces, on the common edge of which there were channels for vertebral retainers, one of the faces was located on the dorso-lateral side of the tail, and the other on the ventrolateral side of the tail, and the through-hole was directly above the surgical wound (working position). The choice of the optimal length of the device and the diameter of the circle inscribed in the hexagon, which is a cross section of the inner cavity of the prism (hereinafter - the diameter of the inscribed circle), were selected experimentally by varying them. At the same time, 12 fixture options were tested, in 5 of which the fixture length was varied with a constant (optimal) value of the diameter of the inscribed circle (Ш series of experiments), and in 7 others, the diameter of the inscribed circle was varied with constant (optimal) value of the length of the device (IV series of experiments). The length of the device was determined as a dependent value on the length of the tail of the rat, measured from the tip of the tail to the sacrum (hereinafter - the “tail length”). The diameter of the inscribed circle was determined as a dependent value on the outer diameter

the tail of the rat in the region of the third caudal vertebra (hereinafter - the “tail diameter”). The length of the tail was measured with a centimeter ruler, and the diameter of the tail with a centimeter tape. Each value of the variable parameter was tested on a group of animals of 5 individuals. The observation period is 14 days. The distribution of animals in series and groups when testing adaptation options with different lengths and different inscribed circle diameters was as follows: W series of experiments: the adaptation length in groups nos. 14-18 was

accordingly: 1/6 (0.17); 1/5 (0.20); 1/4 (0.25);

1/3 (0.33); 1/2 (0.50) tail length; IV series of experiments: inscribed circle diameter in groups No. 19-25

amounted, respectively: 1.4; 1.6; 1.8; 2.0; 2.2; 2.4;

2.6 tail diameters.

The test results in the I-IV series of experiments were evaluated using clinical and radiological studies.

During clinical trials in operated animals, the presence or absence of behavioral disorders, the state of the wound and tail as a whole (mobility, sensitivity, the presence of non-photic changes), the presence or absence of spinal deformity, and the integrity of the device and the presence or absence of its displacement were determined within the observation period from working position. In addition, in all series of experiments, immediately after the completion of each of the vertebral clamps, the angle of setting of this clamp (actually obtained value) was measured (visually with the help of a protractor).

X-ray studies were carried out on the apparatus "Arman 10L6-01 (produced by Kazakhstan instrument-making

factory) in two standard projections (direct and lateral). Radiographs were performed with a direct increase of 4 times on the 7th and 14th day after the operation. Radiographs assessed the presence or absence of destruction of the bodies of fixed vertebrae; the correct ratio of fixed vertebrae and the position of the graft relative to the mother bed.

According to the results of tests of the I and II series of experiments, it was found that the devices that are optimal for placing pairs of through coaxial channels under the vertebral retainers on the lateral surface of the fixation unit so that the axis of each pair is located in a plane parallel to the frontal plane of the projections are optimal. at an angle of 40-50 to the frontal axis (I series of experiments, groups nos. 3, 4; P series of experiments, group 11).

Clinical studies in these groups showed the absence of any abnormalities in the behavior of experimental animals within the observation period of 11 observation, the absence of inconsistency of sutures and suppuration in the area of sutures, the preservation of mobility and sensitivity of the distal parts of the tail, the lack of displacement of the device from its working position and the absence of .ini6o . (damage (in 20-60% of p. 11 studies) of its distal end without disturbing the standing of the vertebral retainers. When analyzing the radiographs revealed: the absence of destruction of the bodies is fixed vertebrae; the correct ratio of the vertebrae in the transplantation zone (in the area of bone grafting); clear standing of the graft in the mother’s bed (on the 7th and 14th day after the operation) .In this case, it was found that the use of a device whose fixation unit made in the form of a straight regular hollow hexagonal prism with through-hole placement

eleven

coaxial channels under the vertebral retainers on four pairwise parallel lateral faces (P series of experiments, group No. 11), contributes to high accuracy of optimal fixation conditions, resulting in the receipt of the positive results described above. These design features make it possible to automatically ensure the passage of each of the clamps through the center of the body of the corresponding vertebra at an angle to the front axis, the value of which (45) is in the middle of the interval of optimal values of the specified parameter (40-50), with a relatively high agreement between the fixture design and the actually obtained values of this angle (deviation within ± 1 j.

When applying adaptation options, in which the axis of each of the pairs placed on the lateral surface of the fixation block of the through coaxial channels was located under the canopy to the front axis, comprising 20 and 30 (I series, groups Nos. 1, 2), for 1-2 days after the operation there was a lack of mobility and sensitivity of the tail, and on 3-4 days after the operation, necrotic changes in the distal parts of the tail (in 100 and 80% of cases), indicating damage to the vessels of the tail. In groups No. 5.6 (Series I), where fixation was carried out using fixture options in which the axis of each pair of through coaxial channels was located at an angle of 60 and 70 relative to the front axis, lateral displacement of the fixture was noted 5-7 days after surgery relative to the axis of the tail and curvature of the tail in the horizontal plane in 80 and 100% of cases. The radiological examinations on the 14th day after the operation showed a displacement of the vertebrae relative to each other; graft loss from the mother bed (in 80-100%). When testing options for accommodation

 C1-ADDED coaxial channels on the lateral surface of the fixation unit so that their axes are located in the sagittal plane at angles to the sagittal axis, comprising:

40 and 50 - when performing the fixing block in the form of a direct crank cylinder (I series, groups No. 7, 8);

45 ° - when performing the fixation unit in the form of a straight regular hexagonal prism (P series, group No. 12),

the results of clinical and radiological studies were obtained, similar to the results of groups No. 1, 2 of the I series of experiments (lack of mobility and sensitivity of the tail with the subsequent development of necrotic changes in the distal parts of the tail in 100% of cases). Variants of fixtures, the design feature of which was the placement of pairs of through coaxial channels on the lateral surface of the fixation unit so that their axes were located in a horizontal plane at angles to the horizontal axis, comprising:

40 and 50 - when performing the fixing unit in the form of a straight circular cylinder (I series, groups No. 9.10);

45 ° - when performing the fixing block in the form of a straight regular hexagonal prism (P series, group No. 13),

caused the absence of tail movements in 100% of cases (which indicated damage to lateral muscle groups), as well as in 40% of cases, bleeding from fixation sites (which indicated damage to large muscle masses).

The test results of Ш and IV series of experiments showed that the optimal length of the device is 0.25-0.33 (1 / 4-1 / 3) of the tail length (Ш series, groups No. 16.17), and the optimal diameter of the inscribed circle is 1.8-2.2 tail diameters (IV series, groups Nos. 21-23). h

In these groups, the results of clinical and radiological studies were similar to the results of groups No. 3.4 (I series of experiments) and group No. 11 (P series of experiments). When using adaptation options with a length of 0.17 and 0.20 (1/6 and 1/5) of the tail length (W series, groups No. 14.15), complete closure of the surgical wound was technically unfeasible, as a result of which, in 100% of cases, a prolonged bleeding from the surgical wound, as well as in 60% of cases - suppuration in the suture area for 3-4 days after surgery. On radiographs on the 14th day after the operation, graft defragmentation was observed in 60% of cases, “vertebral corporeal cornea; in 20% of cases, it is a mixture; the vertebrae are relative to each other. The use of the device, the length of which was 0.5 (1/2) of the tail length (P1 series, group No. 18), led to a violation of the behavioral reactions of experimental animals (difficulty in feeding, moving), which were observed starting from the first day after the operation, in during the entire observation period, which indicated the unjustified weighting of the construction. In groups 19, 20 (IV series), where adaptation options were tested with inscribed circle diameters of 1.4 and 1.6 tail diameters, a lack of mobility and h) tail stiffness were noted for 1–2 days after surgery (100 and 80% of sl) aev); 3 after surgery - necrotic changes in the distal parts of the tail (in 100% of cases), which indicated a violation of blood circulation due to excessive compression of the tail. When using devices whose inscribed circle diameters were 2.4 and 2.6 tail diameters (IV series, groups G№ 24, 25), for 1-2 days after the operation, the device was shifted up or down relative to the longitudinal axis of the tail, which led to

tail curvature in the horizontal plane (respectively, in 60 and 100% of cases). On radiographs on the 14th day after the operation, a shift of the fixed vertebrae relative to each other and a shift of the graft relative to the mother bed were revealed (respectively, in 60 and 100% of cases).

The achievement of the technical result provided by the utility model is due to the following. In modern vertebrology, there is a great demand for osteoplastic and artificial materials that ensure the formation of a reliable block between the vertebral bodies. In the clinic, with instability of the spine, anterior fusion or a combination of anterior and posterior fusion is usually used. The latter option provides high stability in the vertebral motor segment due to the formation of a bone block between the vertebral bodies and the posterior structures of the spine 2. At present, experimental methods play an important role in studying the biological properties of various implants during fusion. At the same time, experimental fusion methods should provide the possibility of comparative testing of implants with different properties to assess the feasibility of using this or that implant with different variants of fusion in humans with the maximum possible simplicity and reliability of the experiment and the minimum time for obtaining indicative results. When conducting fusion operations, the most important task is to ensure stability in the area of the operated vertebral-motor segment, which, as a rule, is achieved with the help of special metal structures 2, 3, 4, 5. Accordingly, the fusion simulation also requires

/ / f y special devices for fixing the vertebral motor segments of the experimental animal.

The claimed device is intended for fixation of the vertebral motor segments of an experimental animal, mainly a rat, in the region of the third to fourth caudal vertebrae (when placing an implant between the third and fourth caudal vertebrae). Given that this implantation zone provides the possibility of the formation of a bone block between the vertebral bodies and the posterior structures of the spine, the proposed device can be implemented when modeling anteroposterior fusion. In addition, the specified localization of the implantation zone and, correspondingly, the fixation zone eliminates the possibility of damage to the organs of the retroperitoneal space (aorta, kidneys, ureters) during surgery. The main design features of the claimed device (the shape of the fixation unit, the features of the implementation and placement of channels under the vertebral retainers) actually provide the possibility of fixation using the so-called “rod method” (according to the ratio of the sizes of the retainer and the fixed vertebra), allowing to capture a smaller number of segments and smaller segments. The authors of the utility model experimentally established that when using the device, the stability of the location of the fixed vertebrae both relative to the implant and relative to the implant is achieved by fixing two vertebrae (one of which is located cranially and the other caudally relative to the implant), and each of them with only one retainer. At the same time, the authors of the utility model experimentally proved that such minimization of the characteristic parameters of fixation allows practically

completely eliminate the possibility of destruction of the structures of fixed vertebrae (even with their small sizes), as well as the likelihood of damage to the spinal cord. In addition, the risk of developing infectious complications caused by the introduction of a large number of vertebral fixatives (in particular, staple osteomyelitis), as well as bone lysis around the fixators, is almost completely eliminated. And finally, these features of the device make it possible to use it on small laboratory animals, in particular on rats with high survival, resistance to infection and a high speed of repair processes. Features of the implementation and placement of channels under the vertebral retainers in combination with the shape of the fixation unit ensure that the optimal conditions of fixation (experimentally established by the authors of the utility model) are met - they allow for relatively high accuracy to hold the fixator through the center of the body of the fixed vertebra in a plane parallel to the frontal plane of the projections at an angle of 40 -50 to the frontal axis passing through the center of the body of this vertebra. This leads to the fact that when the device is placed in the working position, the latch is perpendicular to all planes in which Morjn tail movements occur during the work of various groups of tail flexor muscles (lateral-lateral and ventral-dorsal). Such placement of the lock provides a lock on all possible types of tail movements, which minimizes the probability of tail decentration (tail curvature in the horizontal plane). This, in turn, helps to maintain the shape of the mother bed for the implant and almost completely eliminates the possibility of displacement of the implant (with its relatively high mechanical strength) or

. s crushing the implant (with its relatively low mechanical strength). Moreover, these design features of the device not only ensure compliance with the optimal conditions of fixation during the operation of spinal fusion, but also allow you to save them in the dynamics of the experiment. Thus, the claimed device is the main means for creating and functioning during the experiment a system of rigid extra focal external fixation, which ensures the stability of the location of the fixed vertebrae during the formation of the bone block, while eliminating the possibility of damage to the vital anatomical organs and structures of the spine in the fixation zone. Under the conditions of functioning of this fixation system, the implant plays a purely biological role, fulfilling only osteoinductive and osteoplastic functions; Functional fixation of the spine takes on the device, as an integral element of the system. This, in turn, provides a high probability of the formation of a full-fledged bone block in all experimental animals during implant placement with both relatively high mechanical strength (comparable with vertebral strength) and relatively low mechanical strength. In addition, the design features of the implementation of a number of elements of the proposed device, as well as the features of their placement, provide in a specific form of the utility model additional strengthening of the claimed technical result, or obtaining additional technical results. So, a specific optimal form of execution of the fixation unit (in the form of a regular hollow six-prism prism) in combination with the features of the execution of channels for vertebral retainers (in particular, their pairwise v

c - coaxiality) and their placement on the lateral faces of the nrisma (in particular, with respect to the central axis of the prism and the longitudinal axis of symmetry of the lateral faces) contributes to an additional increase in the accuracy of optimal fixation conditions. In particular, these design features increase the accuracy of the installation of the clamps, which further increases the likelihood of each of the clamps passing through the center of the body of the fixed vertebra, and also provides a specific value (45) of the angle of each clamp (relative to the frontal axis passing through the center of the body of this vertebra), which is in the middle of the interval of optimal values of the specified parameter (40-50 °). Placing several through channels for vertebral retainers (up to 3) on each of the four parallel parallel lateral faces of the prism (up to 3) allows 5D1 to read individual variability of the anatomical parameters of experimental animals. The optimal length of the device further enhances the stability of fixation and simplifies the experimentation. This is due to the fact that, on the one hand, the possibility of suppuration in the suture area is excluded, which, in turn, supplement. helps to eliminate the possibility of displacement of the implant relative to the mother bed and its defragmentation. On the other hand, the use of devices of optimal length helps to reduce pain in the experimental animal and allows for freedom of movement of the latter in the cell, which determines the competitiveness of the animal during feeding. As a result of this, the need for isolated keeping of each individual experimental animal is eliminated. The correspondence of the profile of the inner through cavity of the fixation unit and the profile of the outer surface of the latter simplifies the execution

U / 6 9 fixation and creates technical convenience when using through channels under the retainers of the vertebrae. The optimal diameter of the inscribed circle, on the one hand, eliminates the possibility of severe infectious complications (necrosis of the distal parts of the tail), which in some cases can lead to the death of an experimental animal. On the other hand, the optimal values of this parameter contribute to an additional increase in the stability of fixation by eliminating the possibility of the implant being displaced relative to the mother bed due to the curvature of the tail of the experimental animal in the horizontal plane due to the displacement of the device from its working position. The presence of a viewing hole located on the side of the prism that does not contain channels for vertebral retainers, on the one hand, increases the convenience of suturing the surgical wound, which helps to eliminate the likelihood of bleeding from the wound in the postoperative period. On the other hand, the presence of a viewing hole in combination with the features of its placement eliminates the need for x-ray control during the operation AND immediately after it, which simplifies the operation of spinal fusion and the design of the experiment as a whole. In addition, the viewing hole further helps to eliminate the likelihood of spinal cord injury. Thus, it is the claimed combination of elements of the device for fixation, the peculiarities of their implementation (shape, parameters) and their relative position that makes it possible to simulate anteroposterior fusion using implants with different biological properties, with the exception of

. POSSIBILITIES for damage to vital anatomical organs and structures of the spine in the fixation zone. This is achieved by ensuring the stability of the location of the fixed vertebrae during the formation of the bone block both relative to each other and relative to the implant, while minimizing the values of the characteristic parameters of fixation. The utility model is illustrated by drawings, where in Fig.1 shows a General view of the claimed device (axonometric projection); figure 2 - device in 3 types (frontal section aa); in Fig. 3 the image of the device installed in the working position on the tail of the rat (frontal section BB). The claimed device, made in the form of a straight regular hollow hexagonal prism, consists of walls (side faces of the prism) 1, 2, 3, 4, 5, 6; internal through cavity 7, which is located along the central axis of the prism, and its profile corresponds to the profile of the outer surface of the prism, and six pairs of ABSOLUTELY coaxial channels 8i9, YuiI, 12 and 13, 14 and 15, 16 and 17, 18 and 19. Through channels 8 , 10, 12 and 9, 11, 13 are made on parallel lateral faces of the prism (walls), respectively, 2 and 5, and through channels 14, 16, 18 and 15, 17, 19 - on parallel side faces, respectively, 6 and 3 so that the axis of each pair of channels, respectively, 8i9, 10i11, 12i 13, 14i 15, 16i17, 18i19 intersects the central (horizontal) axis of the prism and longitudinal) then the axis of symmetry of each of the two mutually parallel lateral faces, on which the channels of this pair are located. So, the axis KKi of the pair of channels 14 and 15 intersects the central (horizontal) axis of the prism at point O, as well as the longitudinal axis of symmetry LLi of the side face 6 and the longitudinal axis of symmetry MMi of the side face 3, respectively, at points KI and Kz (Fig. 2 view front, top view, side view). In this case, the angle

between the axis KKi and the front axis OiOi - angle KOO2 - is 45 (Fig.2 front view). The centers of the inlets of the through channels located on each of the side faces are located on the longitudinal axis of symmetry of the corresponding face. So, for example, the centers of the inlets of the channels 8, 10, 12 are placed on the longitudinal axis NNi of the side face 2 (FIG. 2 is a top view, a side view); the centers of the inlet channels 14, 16, 18 - on the longitudinal axis LLi of the side face 6 (Fig.2 top view); the centers of the inlet channels 15, 17, 19 - on the longitudinal axis MMi of the side face 3 (Fig.2 side view). In this case, the centers of the channel inlet openings closest to the ends of the device, for example 8, 14, 15, are located at a distance of 5-7 mm from the corresponding bases of the prism, and the distance between the center of the channel inlet openings located on one side face, for example channels 8, 10 , 12 at face 2, channels 14, 16, 18 at face 6, channels 15, 17, 19 at face 3, are equal to each other and comprise 1.5-2 mm. The diameters of the cross section of the channels in each of the pairs are equal to each other and correspond to the diameter of the cross section of the vertebral retainer, conducted through the channels that make up this pair (working channels). For example, an injection needle (hereinafter referred to as the “needle”), a needle, and the like are used as a vertebra fixator. When using a needle with a cross-sectional diameter of 1 mm, working channels, for example 8 and 9, 14 and 15, were made with a cross-sectional diameter of 1 mm. The optimal length of the device (the length of each of the side faces of the prism) is 0.25-0.33 of the length of the tail of the rat. For example, with a tail length of 10 cm, the device was made 3.0 cm long. The optimal diameter of a circle inscribed in a hexagon, which is a cross section of the inner cavity 7 of the prism, is 1.8-2.2 of the outer diameter of the rat tail in the region of the third vertebra .

For example, with a tail diameter of 0.5 cm, the device was made with the diameter of the indicated circle equal to 1.0 cm. Accordingly, the width of the side face of the prism (the side of the hexagon at the base of the prism) was 0.6 cm. The device can be made, for example, from polyethylene. Crowd of walls not less than 1-2 mm. The device is additionally equipped with a through inspection hole 20, designed to monitor the progress of the operation. The inspection hole 20 is made on the side of the prism, which does not contain channels under the vertebral retainer, for example, on the side of the prism 1. The length of the inspection hole is 0.8-1.0 the length of the side face of the prism, and its width, as a rule, corresponds to the width of the side face. For example, with a side face length of 3.0 cm and a face width of 0.6 cm, the size of the inspection hole was (2.4 x 0.6) cm.

The claimed device is used as follows. Rats are used as experimental animals. Osup1; carry out an experimental operation to simulate anteroposterior fusion. As implants, implants can be used with different biological properties (including those with different mechanical strengths), in particular bone grafts (for example, fetal bone allografts prepared by standard methods, spongy washed allografts, cortical allografts), as well as implants made of synthetic materials (e.g. hydroxyapatite or corundum ceramics). Immediately before the start of the operation, the rat is placed on the operating table on the abdomen, fixing its paws and body, for example, with the aid of a nylon tape. The rat is given anesthesia, for example, ether. Antiseptic treatment of the tail and the rear third of the body of the animal is carried out, for example with a 96% solution of ethyl alcohol. Perform

, t

a longitudinal section in the projection of the third, fourth caudal vertebrae from the dorsal surface of the tail of the animal. Tissues are acutely and bluntly disconnected to the bone structures of the spine, for example using a scalpel and tupfer. Then form the mother bed for the implant between the third and fourth caudal vertebrae. At the same time, the substance of the intervertebral disc and the pineal gland plates of the bodies of the third and fourth vertebrae are removed mechanically, for example, using a drill at a boron rotation speed of 1500 rpm. An implant is placed in the formed maternal bed (groove between the vertebrae). After that, fixation is carried out adjacent to the implant vertebrae (third and fourth) using the claimed device. To fix the fixation device and the device is installed in the working position. In this case, the tail 21 of the rat is introduced into the inner through cavity 7 of the prism and the device is installed so that the central axis of the device is aligned with the longitudinal axis of the tail; the surgical wound was located directly under the inspection hole 20; one of the ends of the device (one of the bases of the prism) is located at the base of the tail, and the second end is caudally outside the surgical wound; two non-adjacent lateral faces of the prism, on which the through channels are made under the vertebral retainers, for example, faces 2 and 6, were located on the dorso-lateral sides of the tail, and two other non-adjacent lateral faces with through channels, pairwise parallel to the indicated faces, for example, the lateral faces 5 and 3 , - from the ventro-lateral sides of the tail. Vertebra latch - the needle 22 is inserted into the inlet of the through channel 8 under the ligament of the vertebra on the lateral face 2 of the prism, passed through the specified channel and output through the outlet of the channel 8 into the internal cavity 7 of the device. Then, needle 22 is inserted through the skin with

D G / 4 - dorsal-lateral side of the tail at an angle of 40-50 to the frontal axis passing through the center of the body of the third caudal vertebra (measure the angle, for example using a protractor). A needle 22 is passed through the center of the body of the third caudal vertebra 23, brought to the opposite ventro-lateral side of the tail, passed through the through channel 9 on the lateral face 5 of the prism and brought out through the outlet of the designated channel. Then, the external fixation of the needle 22 is performed: the needle is bent, for example, using a needle holder, while the free end of the needle is bent over the side rib between the side faces 5 and 4 of the prism, and then it is turned through an angle of 90 to the side face 5 of the prism (which creates a clamp tension vertebra). Similarly, the second retainer of the vertebra - the needle 24 is passed through the through channel 14 on the lateral face 6 of the prism, through the center of the body of the fourth caudal vertebra, through the through channel 15 of the lateral face 3 of the prism, is removed from the device and the external fixation of the needle is carried out. After the device is installed in the working position (both retainers of the vertebra are drawn through the bodies of the caudal vertebrae at an angle of 40-50 ° to the frontal axis passing through the center of the body of the corresponding vertebra and are fixed) through the inspection hole 20, visually check the correct position of the implant in the mother’s bed. Then the surgical wound is sutured with 2-3 interrupted sutures. 1.5-2 months after the operation, the fixation needles are removed from the rat vertebral bodies and from the corresponding through channels on the lateral faces of the prism and the device is removed.

The claimed device was used to model spinal fusion during experimental studies of the biological properties of bone grafts with different mechanical strengths. Produced anteroposterior fusion in experimental

d)

i x animals, as described above, using three types of transplants (produced by the R. Vreden Russian Research Institute of Traumatology and Orthopedics / RosNIIITO /, tissue harvesting and preservation laboratory):

fetal bone adografts;

spongy washed allografts from adults;

cortical allografts from adults.

All types of transplants were procured, preserved and sterilized (in a modified solution of 31 E) according to standard methods and stored in the refrigerator from 2 weeks to 3 months at a temperature of (-8) - (-10) С.

3 series of experiments were conducted on 60 sexually mature laboratory rats under standard conditions (20 animals in each series). The observation period for experimental animals is 2 months.

For comparison, all of these types of transplants were also tested when modeling anterior fusion according to method 6 with a modification of the fixation stage. At the same time, according to the indicated technique, left-side lumbotomic access to the vertebral bodies was performed, the mother bed for the transplant was formed in the form of a rectangular defect (groove) in the bodies of the fourth and fifth lumbar vertebrae and the graft was inserted into the defect formed. The transplant was fixed. 11 was performed using the prototype device according to Method 1. The surgical wound was sutured in layers. 3 series of experiments were conducted on 30 adult purebred dogs (10 animals in each series). The observation period for experimental animals is 4 months.

The distribution of experimental animals in a series of experiments was carried out as follows:

D e // F

27 Series (rats) - fetal bone allografts (from rat fetuses); Series II (rats) - spongy washed allografts from adults (from the metaphysis of the thigh of rats); Ш series (rats) - cortical allografts from adults (from the diaphysis of the femur of rats); IV series of experiments (dogs) - fetal bone allografts (from the fruits of dogs); V series (dogs) - spongy washed allografts from adults (from the metaphysis of the hip of dogs); Series VI (dogs) - cortical allografts from adults (from the diaphysis of the femur of the dogs). The test results in the I-VI series of experiments were evaluated using clinical, radiological, histological and pathological studies. During clinical trials in operated animals, the presence or absence of behavioral disorders, neurological disorders, the state of the wound and tail as a whole (mobility, sensitivity, the presence of necrotic changes), the presence or absence of spinal deformity were determined within the observation period. According to the results of the timing of the authors of the utility model, the duration of the operation of fusion was determined. We also evaluated intraoperative mortality (the number of deaths of experimental animals on the operating table from blood loss). At the same time, animals that died during the operation were replaced with new ones so that the number of individuals in the group remained constant.

X-ray studies were performed on an Arman 10L6-01 apparatus (manufactured by the Kazakhstan Instrument-Making Plant) in two standard projections (direct and lateral). Radiographs were performed with a direct increase of 4 times on the 14th day, on the 30th day (after 1 month), on the 45th day (after 1.5 months), on the 60th day (after 2 months) after the operation - in rats and dogs; 3 and 4 months after surgery - in dogs. The radiographs assessed the dynamics of the presence or absence of fraying of the bodies of the fixed vertebrae; the correct ratio of the fixed vertebrae and the position of the graft (s) relative to the mother bed; radiological changes occurring in the used graft (s) and the mother’s bed (the presence and progress of the process of bone block formation and the timing of its completion, or the absence of this process); the presence or absence of spinal deformity.

For histological studies, animals in each series were withdrawn from the experiment in the following periods after surgery: rats - after 1.5 months (10 animals) and after 2 months (10 animals); dogs - after 3 months (2 animals) and after 4 months (8 animals). When collecting experimental material, the third and fourth caudal vertebrae were extracted from rats, and the fourth and fifth lumbar vertebrae from dogs were extracted. The preparations were fixed in a 10% formalin solution for 3-4 weeks. Plots taken for histological examination were decalcified in a 10-15% solution of nitric acid. After washing, the preparations were degreased with alcohol; then they were poured into liquid and then into thick celloidin. Sections were stained with hematoxylin-eosin and Van Gieson according to standard methods 7. The morphological changes occurring in the

Transplant (s) and maternal bed (presence and progress of the process of formation of the bone block and the timing of its completion, or absence of this process). Pathological studies were carried out as follows. After removal from the experiment, an opening of the operation zone and isolation of the place where bone grafting was performed were performed in each animal. The integrity of the bodies of the fixed vertebrae, the presence or absence of damage to the spinal cord, as well as the presence or absence of damage to organs of the retroperitoneal space were determined. In addition, during pathological examination, tissue was taken from a bone block for histology in each animal. The summary results of the major, radiological, histological and pathological studies are presented in tables 1,2. From the data of table 1 it can be seen that when modeling spinal fusion using both the declared device and the prototype device for staging all types of test grafts in all experimental animals (100%), a bone block was formed (respectively, between the vertebral bodies and the posterior spinal structures; between vertebral bodies); which was completed, as a rule, in the following periods after surgery: with the use of fetal bone ash transplants: I series of experiments (rats) - after 1.5 months; IV series of experiments (dogs) - after 3 months; when using spongy washed allografts: P series of experiments (rats) - after 1.5-2 months; u u di / h

 / burn when using cortical allografts; Ш series of experiments (rats) - after 2 months; VI series of experiments (dogs) - after 4 months. Moreover, when using both the claimed device and the prototype device, there were no cases of transplant displacement (s) and spinal deformity. This was confirmed by the results of x-ray, histological and clinical studies. From the data of table 1 it also follows that the use of the claimed device allowed to reduce the duration of the operation of fusion (compared with the use of the device of the prototype) by 20-24 times (the duration of the operation using the claimed device is 15-20 minutes; using the device of the prototype - 5 -8 h). The data presented in table 2 show that when performing fusion with the claimed device in all series of experiments (1-PG) there were no cases with a fatal outcome during surgery. There were no cases of impaired behavior, neurological disorders. In all experimental animals after the operation, the mobility and sensitivity of the tail remained (clinical observations). The results of x-ray and pathological studies have shown the absence of destruction of the structures of the fixed vertebrae. No infectious complications were noted, in particular spinal osteomyelitis (according to clinical, radiological, histological and pathological studies) .In addition, pathological studies indicated the absence of any damage to the spinal cord and retroperitoneal organs in all rats in all series of experiments.

during sioidylodesis using the prototype device (as can be seen from table 2), in all dogs (in 100% of cases), in all series of experiments (IV-VI), behavioral disturbances were observed in the form of prolonged postoperative excitation (within 1-2 days after surgery) . According to the results of clinical studies, neurological disorders in the form of paresis of the lower extremities of varying severity were noted:

when using fetal allografts (IV series of experiments) - in 10% of cases;

when using spongy washed allografts (V series of experiments) - in 20% of cases;

when using cortical allografts (VI series of experiments) - in 10% of cases.

Neurological disorders, as a rule, were observed in cases where subsequent pathological studies revealed damage to the spinal cord (IV and VI series of experiments - in 10% of cases in each; V series of experiments - in 20% of cases). In the IV and VI series of experiments, there were infectious complications (with joint osteomyelitis) in 10% of cases in each series (according to the results of clinical, radiological, histological and pathological studies).

X-ray and pathological studies showed the destruction of vertebral structures:

when using fetal allografts (IV series of experiments) - in 20% of cases;

when using spongy washed allografts (V series of experiments) - in 50% of cases;

 when using cortical allografts (VI series of experiments) - in 30% of cases (on radiographs starting from the 7th day after the operation: fragmentation of bodies and arches of fixed vertebrae). In addition, cases of aortic damage with hemorrhage into the abdominal space (death on the operating table from hemorrhage) were recorded: when using fetal and spongy washed allografts (IV and V series of experiments) - in 2 dogs (in each series); cortical allografts (VI series of experiments) - in 1 dog. Thus, the comparative tests showed that spinal fusion modeling using the claimed device for fixation allows us to evaluate implants with different mechanical strengths, including implants with relatively low strength characteristics (fetal bone allografts) for their suitability for use in both anterior and posterior fusion. Moreover, when using the claimed device, the duration of the operation of spinal fusion is reduced by 20-24 times, and the terms of the experiment are reduced by 1.5-2 months (compared with the use of the prototype device). In addition, the claimed device allows you to almost completely eliminate the possibility of damage to vital vital anatomical organs and structures of the spine in the fixation zone. And finally, the proposed device in comparison with the device of the prototype is technically simpler to manufacture, while ensuring high reliability of the experiment. h SOURCE OF INFORMATION 1.Kirsanov KP, Marchenpsova L.O. Features of fixation of the lumbar spine by the Ilizarov apparatus in the experiment. // Treatment of injuries and diseases of the musculoskeletal system using transosseous osteosynthesis according to Ilizarov (scientific works). / Ed. Corresponding Member of the Academy of Sciences of Tatarstan, MD prof. Kh.Z. Gafarova. - Kazan: All-Union. Kurgan Scientific Center “Reconstructive Traumatology and Orthopedics, 1992. - v. 39, part 1. - P.31 -34 (prototype). 2.Ulrich E.V. Anomalies of the spine in children. - SNB .: Sotis, 1995.S. 226- 252. 3. GurrK.R., McAfee P.C., ShihC.M. Biomechanical analysis of anterior and posterior instrumentation systems after sophomy // J.-Bone and Joint Surgery. - Am. vol. 70 (8) 1988.- P. 1182-1191 4.HopfC. bidikation und Ergebnisse des CD-Verfahrens in der operativen Skoliosetherapie // Beitr. Orthopad Tramnatol - 1990 - 37, No. 7 S. 401-403 5. Ryan. Bolt-Plate Fixation for Anterior Fusion // Clinical Orthopedics and Related Research. - (203) 1986.- P.196.

6.Brus.I.

Plastic surgery of the spine with formalized homotransplants (experimental study): Abstract. dis. for a job. scientist step. Cand. honey. Sciences / Chisinau State. honey. in.- Chisinau: Publishing House of the Central Committee of the Communist Party of Moldova, 1972. - 17 p.

7. The textbook of histology. / ed. Yu.I. Afanasyev and N.A. Yurina. ed. 4th. -M .: Medicine, 1989.-S. 9-18.

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Claims (12)

1. A device for fixing vertebral motor segments of an experimental animal during spinal fusion, comprising a fixation unit with fastening elements of vertebral retainers mounted on it, characterized in that the fixation unit is made in the form of an elongated geometric body having an internal through cavity located along the central axis of the geometric body, and the fastening elements of the vertebral retainers are made in the form of at least two pairs of through coaxial channels under the vertebral retainers located on the side the surface of the geometric body, and the channels under the vertebral retainers in each pair are made identical to each other in cross-sectional diameters and placed on the side surface of the geometric body in such a way that the axis of each channel pair is located in a plane parallel to the frontal plane of the projections, at an angle of 40 50 ^o to the front axle and intersects the geometrical central axis of the body, inlets and channels of different pairs are arranged on the side surface of the geometric body about its longitudinal central th axis.  2. The device according to claim 1, characterized in that the length of the elongated geometric body is 0.25-0.33 of the tail length of the experimental animal.  3. The device according to claim 1, characterized in that the profile of the inner through cavity of the elongated geometric body corresponds to the profile of the outer surface of the latter.  4. The device according to claims 1 and 3, characterized in that the diameter of the circle inscribed in the geometric figure, which is a cross section of the inner through cavity of the elongated geometric body, is 1.8-2.2 of the outer diameter of the tail of the experimental animal in the third region caudal vertebra.  5. The device according to claim 1, characterized in that on the lateral surface of the elongated geometric body, a through inspection hole is made.  6. The device according to claim 1, characterized in that the fixing unit is made in the form of a straight regular hollow hexagonal prism.  7. The device according to claim 6, characterized in that the through channels for the vertebral retainers are located on four pairwise parallel side faces of a straight regular hollow hexagonal prism, and on each of two mutually parallel side faces, these channels are made pairwise coaxial, and the axis of each channel pair intersects the longitudinal axis of symmetry of each of two mutual parallel faces on which the channels of this pair are located.  8. The device according to claim 7, characterized in that on each of the four pairwise parallel lateral faces there are 1-3 through channels for vertebral retainers, the centers of the inlet openings of which are located on the longitudinal axis of symmetry of this side face.  9. The device according to claims 7 and 8, characterized in that the through channels for the vertebrae retainers, comprising different pairs, are placed on adjacent side faces of the prism.  10. The device according to claims 2 and 6, characterized in that the length of the side face of the straight regular hollow hexagonal prism is 0.25-0.33 of the tail length of the experimental animal.  11. The device according to claims 3, 4 and 6, characterized in that the diameter of the circle inscribed in the polygon, which is a cross section of the inner cavity of a straight regular hexagonal prism, is 1.8-2.2 of the outer diameter of the tail of the experimental animal in the region third caudal vertebra. 12. The device according to claims 5 and 6, characterized in that the through inspection hole is made on the lateral edge of a straight regular hollow hexagonal prism that does not contain channels for vertebrae retainers.