RU2494469C1 - Method for experimental correction of intervertebral disc defect - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: pulpal core is removed from the intervertebral disc. A three-dimensional chondral graft containing including poorly differentiated chondrocytes with high potency to synthesis and proliferation is laid onto a bed of the pulpal core. The chondral graft size is matched with the defect size.

EFFECT: with the cells of a various degree of differentiation found in the chondral graft, the method provides a complete replacement of the pulpal core, disc height recovery in a relatively short time, and prevents its further degenerative changes.

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Description

The invention relates to experimental medicine, namely to traumatology and orthopedics, and can be used in the treatment of early stages of osteochondrosis, as well as for the correction of traumatic injuries of the intervertebral disc.

A known method of obtaining a pulpous nucleus. Cells of the pulpous nucleus of the intervertebral disc of the tail of a cow were cultured on the surface of a bone substitute (calcium phosphate) and kept for 6 weeks in culture medium. A portable pulpous nucleus was formed, which was similar in histological, biochemical parameters and compression mechanism to the native pulpous nucleus (Seguin CA, Grynpas MD, Pilliar RM, et al. Tissue engineered nucleus pulposus tissue formed on a porous calcium polyphosphate substrate // Spine, 2004 ; 29: 1299-1307).

The disadvantages of this method are the use of highly differentiated cells with low proliferative potential and the use of carrier matrices, which is a resorbable material that is a foreign body that impedes the adaptation and metabolic cooperation of transplanted and maternal chondrocytes.

A known method of transplantation of chondrocytes into the region of an altered intervertebral disc. Autologous chondrocytes were isolated from disc herniation biopsies and cultured for 12 weeks. Autologous chondrocytes were injected into the intervertebral discs of the lumbar spine in patients aged 18 to 60 years. (Volkov A.V. Cellular technologies in traumatology and orthopedics: developmental paths // Cellular transplantology and tissue engineering Volume II, No. 4, 2007).

The main disadvantage of the method used is the use of highly differentiated cells taken from dystrophically altered tissue (intervertebral hernia), which will not ensure the functional usefulness of the disk.

Closest to the claimed is a method of preventive correction of dystrophic changes in the intervertebral discs by cell engineering (Zaydman AM, Korel A.V., Kim II, Markin SP "The possibility of preventive correction of dystrophic changes in the intervertebral discs by cell engineering" // Spinal Surgery No. 3, 2007). Native chondrocytes were obtained by the method described in patent RU No. 2285039. Cultured cells were transplanted into the pulp nuclei of the intervertebral discs of the lumbar in adult dogs using a thick needle. The wound was sutured in layers tightly. The advantage of this method is that highly, medium, and low-differentiated cells capable of active synthesis and further differentiation were introduced into the pulpous nuclei of the intervertebral discs. The replenishment of the cell population and the synthesis of the matrix ensures the maintenance of structural integrity and homeostasis of the intervertebral disc.

The main disadvantage of this method is the injection of a suspension of chondrocytes into the pulp nucleus, since the probability of damage to cells during transplantation increases. Chondrocytes, deprived of an adequate microenvironment, go through the stage of metabolic adaptation. In this regard, the specific differentiation of transplanted cells is delayed in time.

The objective of the invention is to develop a method for restoring the structure and function of the intervertebral disc by introducing a three-dimensional chondrotransplant into the pulp core of the bed to correct dystrophic disorders in the early stages of osteochondrosis.

The problem is solved due to the fact that the pulpous nucleus is removed from the intervertebral disk, a three-dimensional chondrotransplant containing low-differentiated chondrocytes with high potential for synthesis and proliferation is placed in the bed of the removed pulpous nucleus of the intervertebral disk, while the size of the chondrotransplant corresponds to the size of the defect.

The solution of this problem allows us to restore the structural and functional integrity of the intervertebral disc and prevent its further degenerative changes.

The technical result is achieved due to the fact that the three-dimensional chondrotransplant contains low-differentiated chondrocytes with a high potential for synthesis and proliferation. A chondrotransplant transplanted into the corresponding metabolic environment of the cavity of the pulpous nucleus completely fills the defect and, differentiating into hyaline cartilage, ensures restoration of the structural and functional integrity of the intervertebral disc. Preserving the cell metabolism of the pulpous nucleus prevents dystrophic changes in the fibrous ring. Chondrotransplant does not cause antibody aggression, which helps to avoid inflammation and rejection in the postoperative period.

The method is as follows.

After preliminary administration to anesthesia, the dog has left oblique extraperitoneal access to the lumbar vertebrae. The front surfaces of the vertebral bodies with adjacent intervertebral discs are exposed. A U-shaped dissection of the anterior longitudinal ligament, the anterior part of the fibrous ring is carried out, the pulpous nucleus of the intervertebral disc is visualized. Volkman's small spoon pulp nucleus is removed from the intervertebral disc. A three-dimensional chondrotransplant corresponding to the size of the defect formed is placed in the bed of the pulpous nucleus of the intervertebral disc. The dissected anterior portion of the fibrous ring and the anterior longitudinal ligament returns to its original place as a “patch”. A strip of hemostatic sponge is placed on top. Layered seams on the wound. Aseptic dressing.

An example of a specific implementation of the method.

An intervertebral disc defect was simulated in the experiment with its subsequent correction using a three-dimensional chondrotransplant containing low-grade chondrocytes with a high potential for synthesis and proliferation. The control was a defect in the intervertebral disc with the removed pulpous nucleus without correction by a three-dimensional chondrotransplant.

After preliminary introduction into anesthesia of an adult wild-type dog, left-sided oblique extraperitoneal access was performed. The skin, subcutaneous tissue, external and internal oblique muscles, transverse muscle, transverse fascia were dissected. By bluntly stratifying retroperitoneal fiber, the front surface of the lumbar spine was reached. The front surfaces of the bodies L7, L6, L5, L4, L3 of the lumbar vertebrae with adjacent intervertebral discs were exposed. The anterior longitudinal ligament did not exfoliate. The anterior segmental vessels were ligated and intersected along this extent. A thorough wound hemostasis was performed using electrocoagulation. For X-ray identification of vertebral segments in the postoperative period, a metal mark was placed in the vertebral body L7 by driving the tip of the injection needle into the center of the body and biting it. The anterior intervertebral discs L4-L5 and L3-L4 were visualized. By a U-shaped dissection of the anterior longitudinal ligament of the fibrous ring, the pulpous nucleus was visualized. To model defects from the intervertebral discs L5-L4 and L4-L3, Volkman's small spoon removed the nucleus pulposus. In the experimental intervertebral disc L5-L4 in the bed of the pulp nucleus, a three-dimensional chondrotransplant was placed with forceps corresponding to the size of the defect formed when the pulp nucleus was removed. For comparison, a defect correction was not performed in the control intervertebral disc L4-L3. U-shaped dissected fibrous rings of the ring of the discs L5-L4 and L4-L3 together with the anterior longitudinal ligament were installed in their place as a “patch”. On top of the intervertebral discs, hemostatic sponge strips 1 × 2 cm in size were laid. Layered stitches were placed on the wound. Aseptic dressing.

Radiographs were taken before surgery and at the end of the experiment (after 6 months). After 1, 3, 6 months, the dogs were withdrawn from the experiment. Intervertebral disc preparations (experimental and control) were extracted and subjected to morphological and histochemical studies.

The results of the experiment are illustrated by drawings.

Figure 1 is a histological section of an experimental intervertebral disc with a transplanted three-dimensional chondrotransplant 1 month after surgery. (hematoxylin - eosin × 400).

Figure 2 is a histological section of an experimental intervertebral disc 3 months after transplantation of a three-dimensional chondrotransplant (hematoxylin-eosin × 400).

Figure 3 - histological section of the experimental intervertebral disc 6 months after transplantation (hematoxylin - eosin × 200)

Figure 4 - a histological section of the control intervertebral disc with the removed pulp nucleus 1 month after removal of the pulp nucleus (hematoxylin - eosin × 200)

Figure 5 is a histological section of a control intervertebral disc 3 months after surgery (hematoxylin - eosin × 200).

6 is a histological section of the control intervertebral disc 6 months after surgery, (hematoxylin - eosin × 200).

Fig.7 is a lateral radiograph of the dog after 6 months after surgery.

In the experimental intervertebral disc on histological preparations 1 month after transplantation of a three-dimensional chondrotransplant, proliferation of chondrotransplant cells (1) and the formation of chondron structures were observed in the bed of the removed pulp nucleus (1). After 3 months (Figure 2), a chondrotransplant filled the entire space of the bed of the former pulpous nucleus and is closely adjacent to the fibrous ring (3). 6 months after the operation (Figure 3), a hyaline cartilage with a regular arrangement of chondrocytes (4) and a homogeneous matrix (5) was formed in the transplantation zone.

In the control intervertebral disc on histological preparations 1 month later (Figure 4) after removal of the pulpous nucleus, a connective tissue regenerate (6) with small vessels (7) was formed in the defect zone. After 3 months (Figure 5) in the area of dystrophy, the collapse of collagen fibers is observed (8). Active osteogenesis is detected in the lateral parts of the disc (9). After 6 months (Figure 6), osteogenesis with the formation of bone tissue is enhanced in the defect zone (10).

On the lateral radiograph of the dog 6 months after the operation (Fig. 7), in the zone of the experimental intervertebral disc (12), the height of the intervertebral disc remains, there are no radiographic signs of pathological changes. In the area of the control intervertebral disc, a narrowed intervertebral fissure is clearly visible (11). Sclerosis of adjacent parts of the vertebral bodies is observed, anterior bone growths are visible at the level of adjacent vertebrae.

Claims (1)

A method for correcting an intervertebral disk defect in an experiment by introducing cultured chondrocytes, characterized in that the pulp nucleus is removed from the intervertebral disk, a three-dimensional chondrotransplant containing low-grade chondrocytes with high potential for synthesis and proliferation is placed in the bed of the removed intervertebral pulp nucleus, intervertebral disk corresponds to the size of the defect.

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