RU2463668C1 - Method for experimental simulation of delayed distraction osteogenesis accompanying shortening of extremity bones - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: resection of a bone segment and fixation of bone fragments by an osteosynthesis apparatus are followed by fragment coaptation with preserving a diastasis in between not less than 0.5 cm. Then distraction is applied at 1 mm 4 times a day to reduce an initial bone length.

EFFECT: method enables modelling delayed distraction osteosynthesis accompanying shortening of extremity bones for studying the features of formation of the new diaphysis segment in the created unfavourable physiological environment.

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Description

The invention relates to experimental medicine and veterinary medicine, in particular for scientific research in the field of orthopedics and traumatology, and can be used to model delayed distraction osteogenesis in experimental animals.

A known method of modeling delayed osteogenesis, including the preparation of soft tissues adjacent to the bone, transverse osteotomy of the tibia and fixation of bone fragments by the transosseous osteosynthesis apparatus, after which the ends of the fragments are removed from the wound and the contents of the bone marrow cavity are removed from each, then the ends of the fragments are precisely aligned and fixed to fusion (RF Patent. No. 23014557. Modeling Method for Delayed Osteogenesis / Kononovich N.A. (RF), Dyuryagin E.V. (RF), Dyachkov A.N. (RF), Federal State Institution Scientific and Research Center “WTO” named after Acad. G.A. Or Zarova of Roszdrav "(RF); declared. 02.18.2005; publ. 07.27.2006).

However, the known method is used to simulate delayed osteogenesis during fusion of transverse bone fractures and does not imply modeling shortening of the bone with subsequent distraction.

A known method of modeling a defect in a long tubular bone, including resection of its site and fixation by the apparatus, the fragments are conical, the bone marrow is removed from their ends, and the bone marrow-free sections of the cavities are treated with ethyl alcohol, after which the fragments are stably fixed for 2-3 weeks (RF Patent No. 2069896, Method for modeling a defect in a long tubular bone / Kamerin VK (RF), Shreiner AA (RF), Russian Research Center for Reconstructive Traumatology and Orthopedics (RF); - application. 10.02. 1992; publ. 27.11. 1996. - BI. No. 33).

However, the known method does not involve the provision of distraction effects on the fragments, therefore, it cannot be considered as a method of experimental modeling of delayed distraction osteogenesis during shortening of limb bones.

It is known that to simulate delayed bone formation, an osteotomy of the tibia diaphysis is performed with a Dzhigli saw and after 3 days they begin distraction at a rate of 1.0 mm per day in four doses (A. A. Emanov. Features of regenerate formation under conditions of distraction-compression-distraction osteosynthesis / A.A. Emanov, M. [et al.] // Tenth Anniversary Conference of Young Scientists "Actual Issues of Clinical and Experimental Medicine": collection of abstracts. - St. Petersburg, 2010. - 82-83).

However, a well-known version of the simulation of delayed bone formation during distraction osteogenesis does not imply the formation of shortening of the limb.

The objective of the present invention is to develop a method that allows you to simulate delayed distraction osteogenesis when shortening the bones of the limbs and to study the features of the formation of the newly formed area of the diaphysis in the created unfavorable physiological conditions.

The specified technical result is achieved by the fact that in the method of experimental modeling of delayed distraction osteogenesis during shortening of the limb bones after resection of the bone site and fixation of bone fragments by the osteosynthesis apparatus, the fragments are brought closer together with a diastasis of at least 0.5 cm between them, then distraction is performed at a rate of 1 mm for 4 doses per day before restoring the original limb length.

The present invention is illustrated by a detailed description, a clinical example and radiographs, in which:

Figure 1 - a copy of the x-ray of the bones of the leg after resection of the diaphysis and matching bone fragments while maintaining diastasis between them.

Figure 2 - copy of the x-ray of the bones of the leg after 7 days of distraction.

Figure 3 is a copy of the x-ray of the bones of the leg after 21 days of distraction.

Figure 4 is a copy of an x-ray of the lower leg bones at the end of distraction.

The method is as follows.

Under operating conditions, an animal under general barbituric anesthesia after treating the surgical field with 5% alcohol iodine solution imposes an apparatus for transosseous osteosynthesis with the possibility of elongation on a selected segment of the limb of the experimental animal. In the projection of the planned resection of the bone site, a longitudinal skin incision is made, followed by blunt dissection of the soft tissues adjacent to the bone. To shorten the length of the limb through the incision, a section of the bone is resected using a vibropil. The size of the resected area is chosen arbitrarily, based on the objectives of the experiment. After resection of the bone site, its fragments are brought together with the preservation of diastasis between them of 0.8 cm. Then, knotted sutures are applied to the soft tissues. 2 days after the operation, distraction begins at a rate of 1.0 mm per day for the 4th dose until the initial limb length is obtained. After this, the fragments are stably fixed in the reached position until the formation of a mechanically sound newly formed bone region, which allows to stop the hardware fixation.

An example of the method. Case history No. 368, dog No. 4471, age 2 years, weight 25.0 kg, leg length 20 cm.

Under operating conditions in an anesthetized animal, after treating the surgical field with a 5% alcohol solution of iodine, the Ilizarov apparatus, consisting of two subsystems (proximal and distal), was placed on the right shin. Through longitudinal sections of soft tissues from the medial surface in the region of the middle third of the leg with the help of a vibropile, a section of the tibia diaphysis was resected by 6.0 cm, which amounted to 30% of the initial length. After this, the fragments were brought closer while maintaining diastasis between them 8.0 mm (Figure 1). Knotted stitches were applied to the soft tissue. The surgical field was treated with 5% alcohol solution of iodine.

2 days after the operation, distraction was started at a rate of 1.0 mm per day for four doses over 52 days, thereby restoring the original leg length.

7 days after the start of distraction on radiographs, the diastasis between the fragments was 15.0 mm. Visually, the signs of reparative regeneration were not detected (Figure 2).

After 21 days of distraction, the diastasis was 31.0 mm. The proximal and distal bones of the regenerate were weakly expressed. Their height ranged from 1.0 mm to 13.0 mm. The length of the middle zone of enlightenment reached 20 mm. On the surface of the fragments was weakly expressed periosteal reaction (Figure 3).

By the end of the distraction period, the diastasis was 60.0 mm. The bone sections of the regenerate acquired a conical shape and did not unite with each other in the cavity of the diastasis. The length of each of them did not exceed 25.0 mm. Periosteal layers on the fragments were compacted and reduced (Figure 4).

Similar radiological signs indicated a sharp slowdown in distraction osteogenesis in the elongation period, while restoring the length of the shortened tibia of the experimental animal.

The proposed method is used in the laboratory of experimental traumatology and orthopedics of FGU "RRC" WTO "them. Acad. GA Ilizarova »Ministry of Health and Social Development, which allows you to study the features of delayed distraction osteogenesis by creating the same unfavorable conditions for bone formation during limb lengthening, as well as to test known methods for developing distraction osteogenesis at different stages of lengthening.

Claims (1)

A method for experimental modeling of delayed distraction osteogenesis during shortening of limb bones, including resection of a bone site, fixation of bone fragments with an osteosynthesis apparatus with the possibility of elongation, distraction at a rate of 1.0 mm in 4 doses per day, characterized in that after resection of a bone site and bone fixation of fragments by the osteosynthesis apparatus, the fragments are brought closer together with a diastasis of at least 0.5 cm between them, then distraction is performed at a rate of 1 mm for 4 doses per day before recovery one limb length.

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