Replacement Of Tissue Defects Research Articles

Development of biocompatible superelastic materials and shape memory implants based on titanium nickelide for the creation of highly effective medical technologies

The paper presents fundamental and applied research in a new direction in science and technology, which has a world priority – medical materials and implants with shape memory. The main directions of the development of a new generation of more advanced biocompatible superelastic implantable materials and long-term shape memory implants based on titanium nickelide are formulated. The physical, biological principles of creating a new class of biocompatible superelastic materials based on titanium nickelide with a certain set of properties for various fields of medicine using technologies of induction melting, self-propagating high-temperature synthesis, and sintering are presented.Among the materials created, the development of alloys for long-term functioning in a living organism is of great importance: monolithic elastic, porous and ultra-thin porous-permeable materials, fabric and textile materials made of thin filaments based on titanium nickelide. The main medical and technical requirements for a new class of implants of the future have been identified. Criteria for the biomechanical compatibility of metallic materials under deformation conditions in aggressive tissue media have been determined. Conditions are formulated under which monolithic and porous materials exhibit properties that are optimal for implantation. A comprehensive study of the properties of cell incubators made of porous titanium nickelide was carried out, and the morphological characteristics and patterns of cell development in the porous structure of bulk biomaterials made of titanium nickelide were revealed.The main directions of creation of unique medical technologies based on the developed materials are characterized. The principles of application of biocompatible superelastic materials in various fields of medicine are described. Titanium nickelide-based materials and implants with shape memory implanted into the body are intended for a wide range of medical purposes in dentistry, traumatology, surgery, ophthalmology, vascular surgery, oncology and other fields of medicine as implants for osteosynthesis, endoprosthetics, replacement of tissue defects, creating anastomoses and support frames of organs.

Medial Gastrocnemius Flap for Covering Tissue Defects Around the Knee

Summary. Tissue defects of the anterior surface of the lower leg and the knee joint is a severe problem at the treatment of orthopedic patients.
 Objective. Analysis of the results of using the medial gastrocnemius flap (MGF) in orthopedic patients; highlighting peculiarities of surgical technique.
 Materials and Methods. 8 patients (10 cases) who underwent the transposition of the MGF. The age of the patients was 19–74 years (on average 40.5±5.7 years); there were 6 males and 2 females. The list of cases: open fractures – 2 cases, combat injury – 2 patients (3 cases), skin necrosis after osteosynthesis – 3 patients (4 cases), and skin necrosis after total knee replacement – 1 case. The results of treatment were assessed in terms 9 months – 10 years by the Lysholm scale.
 Results. Autodermoplasty during MGF transposition was performed in two cases and after a few days in others. In cases with open fractures, the osteosynthesis and external fixators reassembly were done; conversion of osteosynthesis was performed one month after autodermoplasty. In cases of skin necrosis after osteosynthesis and total arthroplasty, the implants were never removed. Knee function according to the Lysholm scale ranged from 70 to 100 points (mean 88.2±3.3).
 Conclusions. The transposition of the MGF for the replacement of tissue defects of the anterior surface of the lower leg and knee joint is an effective method in orthopedic surgery, which helps to solve the problem of infectious complications and to save the supporting-kinematic function of the lower extremity.

Saving of Foot Support Ability in Post-traumatic Defects Using Microsurgical Tissue Autotransplantation

Background. Severe open injuries of the lower extremities in most cases are the result of high-energy trauma, because the foot and ankle are damaged as a result of automobile accidents almost in every fourth victim. According to the literature, the percentage of infectious complications after surgical debridement of open injuries of the foot is 43–67.9% and shows no tendency to decrease.Material and methods. We performed 32 operations with the use of free revascularized grafts in patients aged from 16 to 70 years with extensive posttraumatic defects of the foot between 2010 and 2018.Results. As a result, 30 (93.7%) out of 32 grafts provided foot support ability provided during the post-operative period. When replacing large defects (more than 80 cm2) of soft tissues supporting surface of the foot we used free musculocutaneous flap of the latissimus dorsi, fasciocutaneous flaps were used for defects of the dorsum of the foot (less than 80 cm2). Long-term results were assessed using the Foot and ankle ability Measure (FAAM) questionnaire.Conclusion. Primary early replacement of tissue defects on the foot with free revascularized autografts is the method of choice for solving this problem, as it allows you to maintain the supporting function of the foot and is often alternative method to amputation.

New Bioplastic Material Based on Hyaluronic Acid Hydrocolloid

Relief of the typical pathological processes and the early activation of regenerative mechanisms are the conditions for the successful wound healing. Reparative potential of epithelial tissues is realized at a balanced migration and proliferation of their cellular elements, synthesis of fibrous proteins and extracellular matrix components, epithelisation. An in-depth assessment was made of the structure of the developed bioplastic material based on hyaluronic acid hydrocolloid (G-Derm) and of its properties, positive in terms of optimizing the reparative mechanisms. Scanning probe microscopy and ultrastructure evaluation of bioplastic material were performed. For investigating the visualized globular structures, homogeneous samples of the material length 101.5 ± 11.2 nm, width 110.3 ± 10.7 nm, height 23.4 ± 3.4 nm were taken. The space between globular formations was 127.2 ± 21.3 nm. It was found that the roughness coefficient of the surface relief (Rq) was 8.7 ± 0.5 nm. The method of fixing the contact angle of water was used to evaluate hydrophilic/hydrophobic properties of biomaterial. Value of the angle was 83°; adhesion coefficient was 99.88 mN/ m2, which characterizes the surface of biomaterial as moderately hydrophilic. Mesenchymal stromal stem cells were cultured on a substrate of bioplastic material based on hyaluronic acid hydrocolloid. In the course of ultrastructural study cell migration into the material was recorded, presence between the interwoven fibrillar fibres of cell layers of an oblong shape 3.7 ± 0.5 mcm wide, which reflects their cooperation with the surface of the developed polymer suitable for the use as a growth substrate in case of biotechnological replacement of tissue defects.

A novel surgical material made from collagen with high mechanical strength: a collagen sandwich membrane.

We have developed a novel collagen membrane with excellent mechanical properties using a new method and examined its breaking strength, microstructure, and absorption behavior in vivo. Types I and III atelopeptide collagen extracted from porcine skin by treatment with pepsin were used. One volume percent collagen hydrochloride solution, pH 3.0, was frozen in a cast, then freeze-dried and pressed. Both surfaces of the resulting membrane were coated with 2% w/v collagen hydrochloride solution, pH 3.0, and dried. This procedure was then repeated 10 times, and the membrane was finally heated in vacuo. Microstructural observation showed that the inner part of the membrane consisted of piles of thin collagen nonwoven fabric layers, whereas the coated surface consisted of an amorphous collagen layer. The breaking strength of this membrane with a thickness of 0.5 mm was 73.5 N/cm in dry conditions. The mechanical strength of the membrane was 3.4 to 10.8 times greater than that of control membranes that had not been subjected to coating procedures. The absorption of this membrane was investigated by an implantation test in rabbits. The absorption rate of the membrane in vivo was similar to that of the noncoated control material, and only minimal tissue reaction was evident. Because the mechanical properties of this membrane, made from only collagen, are adequate for suturing without reinforcement by other materials, and its absorption in vivo has so far been equal to that of collagen membranes, the membrane is potentially applicable for various surgical uses such as replacement of tissue defects.

Tvrdek, M. Contribution of neurovascular microsurgery to replacement of tissue defects by one-stage transfer from remote body areas. (Czech)

Tvrdek, M. Contribution of neurovascular microsurgery to replacement of tissue defects by one-stage transfer from remote body areas. (Czech)

Intracerebral neural implants: neuronal replacement and reconstruction of damaged circuitries.

Neural grafting has emerged over the last decade as a viable approach to studying the development and regeneration of neuronal connections in the CNS ofmamrnals. In this review we focus on one particular aspect of this technique: the use of intracerebral neural implants for the reestablishment of severed connections, the substitution of lost pathways, and the replacement of tissue defects in the adult mammalian CNS. A survey of the literature shows that grafting of neuronal tissue to the mammalian CNS has been frequently attempt­ ed since the end of the last century, but that the results of these earlier studies were generally very poor. Thompson (1890) and Saltykow ( 1905) were possi­ bly the fIrst to report results from grafts of adult CNS tissue, and Del Conte (1907) the fIrst to try grafts of embryonic tissues to the brains of mammals. Their results were generally unsuccessful and no clear-cut evidence of good long-term survival was obtained. Del Conte, in particular, concluded that the brain was an unfavorable transplantation site. Similar negative results were subsequently published, e.g. by Altobelli (1914), Willis (1935), Glees (1955), Wenzel & Barlehner (1969), and Frotscher et al (1970). Some of the early investigators were, however, more successful. Ranson (1914) and Tidd (1932) obtained partial survival of grafted sensory ganglia in the cerebral cortex of developing rats, and Dunn (1917) reported survival of four out of 44 grafts of neonatal cerebral cortex, implanted into the cortex of nine to ten day-old