RU2411923C1 - Method of making alloimplant on basis of cartilaginous tissue - Google Patents

Abstract

FIELD: medicine. ^ SUBSTANCE: invention relates to orthopedics and traumatology and can be applied for making alloimplant on the basis of cartilaginous tissue. Rib cartilage is frozen at temperature -25-30C for not less than 6 hours. Rib cartilage in frozen state is cut in longitudinal direction into 0.5-1 mm thick plates and frozen-dried for 48 hours. After which is it packed into double plastic packet and sterilised by flux of fast-moving electrons with dose 20-25 kGy. ^ EFFECT: method allows to increase storage term, reduce cytotoxic and carcinogenic effects. ^ 1 ex

Description

The invention relates to medicine and can be used in the manufacture of medical devices used in reconstructive, plastic surgery, traumatology and orthopedics. It can be applied in the work of tissue banks of the Russian Federation to provide biological plastic material for healthcare institutions.

In the practice of reconstructive, plastic surgery, there is a need for biological plastic materials that have a set of properties that can adequately replace the defect in the situation, especially cartilage tissue. The area of their use, as a rule, is the tissue of the facial skull (nose, auricles, etc.) and in the neck (cartilage of the trachea, etc.). In the postoperative period, the allograft should serve as a matrix for the restoration of the recipient's own tissues. In the process of preparing the material for implantation, the allograft must have a certain plasticity to give it the necessary shape and size, and also perform a frame function after its implantation.

Known methods of conservation with simultaneous sterilization using only formaldehyde solutions of low concentrations (0.25-0.75%) (Parfentieva VF et al. Preservation of bone tissue in formalin solutions of low concentrations // Methodical letter, CITO. M, 1970 ) Also known is a method of preservation of cartilage, reflected in the patent of the Russian Federation (Razinkov S.P. et al. Method of preservation of cartilage, RF patent No. 2123259). The proposed method of preservation of cartilage is to preserve the transplant in a liquid preservation solution. Cartilage tissue is taken during surgery, treated with physiological saline, placed in a sterile glass container with buckwheat honey and stored at a temperature of + 4-5 ° C. The shelf life with this method of conservation is limited to 60 days.

The closest analogue of the proposed method is a method of manufacturing a cartilage allograft, which consists in sequentially mechanical cleaning of the donor cartilage tissue and placing it in a 0.2% solution of formaldehyde and 0.05% glutaraldehyde with glycerol (1: 4) in a sealed glass vessel followed by storage of the allograft in the refrigerator at a temperature of + 4 ° C until its clinical use. Shelf life is limited to 6-12 months (S. Boltrukevich et al. Procurement, preservation and storage of biological tissues in liquid media // Guidelines. Grodno, 2000). We took him for a prototype.

The disadvantages of this method is that the aldehydes used in the manufacture of allografts have a cytotoxic and carcinogenic effect in proportion to the concentration of formalin used and the duration of its effect on biological objects (see Sat: Skripnyuk P.A. et al. Demineralized bone grafts and their use in reconstructive surgery, S.-Pb., 1996, p.106-109, Feigelman S.S. Orthopedics, traumatology, 1980, No. 12, p.45-50). The use of formalin as a preservative and sterilizer entails a number of problems caused by the limited storage time of the allograft (no more than 6 months), the need for long-term washing of the implant before clinical use, storage using low-temperature refrigerators, glass containers with corresponding inconveniences during transportation.

The objective of the claimed method is to eliminate the above disadvantages, namely the exclusion of the use of aldehydes, obtaining an allograft with preserved mechanical properties of the cartilage, reducing the time of preoperative preparation, increasing the shelf life.

To solve the task of obtaining an allograft based on cartilage tissue, a method is used that includes mechanical cleaning of the donor costal cartilage, quick freezing, slicing the frozen workpiece in the longitudinal direction into plates, lyophilization, subsequent packaging in sealed standard double packets and radiation sterilization with a stream of fast electrons. In this case, the workpiece is frozen at a temperature of -25-30 ° C for at least 6 hours. Then, using a device similar to a microtome, frozen material is cut into plates in the longitudinal direction with a thickness of 0.5-1 mm. Cutting frozen samples allows you to get plates of the required thickness. The manufacture of an allograft in the form of plates with a thickness of 0.5-1 mm facilitates its use, since it is easier to cut out fragments of the required size and configuration from it, thereby reducing the time for their preparation before implantation. After cutting, the material is stored at a temperature of -25-30 ° C until the lyophilization stage. Lyophilization is carried out in a lyophilization installation for 48 hours. The proposed dehydration of the material by lyophilization allows you to fully save the architectonics of the cartilage tissue, thereby preserving the mechanical characteristics of the allograft based on costal cartilage. After lyophilization, the material is packaged in a double plastic bag and sterilized by a stream of fast electrons. The radiation dose required for the most effective sterilization, experiments have shown, is 20-25 kGy, which makes the material safe in terms of bacterial and fungal infections.

An example implementation of the method.

The rib cartilage fragment obtained from the donor is cleaned of soft tissues and blood elements.

Next, the preform is cooled to -25-30 ° C, then using a device similar to a microtome, frozen material is cut into plates with a thickness of 0.5-1 mm. After 7-10 days, lyophilization of the material is carried out for 48 hours.

After dehydration, the preforms are placed in a double plastic bag and sterilized by a stream of fast electrons with an irradiation dose of 20-25 kGy. In this form, the allograft is ready for clinical use. The proposed method of conservation by lyophilization and the method of sterilization by irradiation with a stream of fast electrons extend the shelf life of allografts to 5 years at room temperature.

After surgery, the allograft after opening the package is rehydrated in saline (can be combined with antibiotic and hydrocortisone solutions to create an additional level of prevention of postoperative complications) for 10-20 minutes. The geometric shape of the allograft created at the stage of its manufacture does not require its lengthy preparation and imparting the necessary configuration before implantation.

An example of clinical use.

Patient P., 53 years old, medical history No. 15534, was admitted to the clinic of maxillofacial surgery MONICA about a fracture of the lower wall of the orbit on the left. On a series of tomograms, a defect of the lower wall of the orbit was determined, the dimensions of which were 12 mm in width and 20 mm in length. Clinically marked hypo-enophthalmos, limited mobility of the left eyeball, as well as diplopia when looking up and down. Under endotracheal anesthesia, an operation was performed to eliminate hypo- and enophthalmos by endoscopic transantral access with plastic surgery of the lower wall of the orbit with a fragmented allograft based on cartilage tissue with preliminary reposition of adipose tissue and lower rectus muscle into the orbit. The restoration of the volume of bone and soft tissues of the eye socket made it possible to accurately reposition the eyeball and eliminate hypo-enophthalmos.

During follow-up examinations 1, 3 and 6 months after surgery, there was a complete absence of hypo- and enophthalmos, the movement of the eyeball in full. On the control x-ray examination, the correct position of the eyeball of the musculoskeletal structures and the implant was noted. The patient has no complaints.

Claims (1)

A method of manufacturing an allograft based on cartilage tissue, including mechanical cleaning of the donor costal cartilage, preservation and sterilization, characterized in that the costal cartilage is frozen at a temperature of -25-30 ° C for at least 6 hours, longitudinally cut into longitudinal plates 0.5-1 mm thick, lyophilized for 48 hours, packaged in a double plastic bag, sterilized by a stream of fast electrons with a dose of 20-25 kGy.