• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.911-914
• /
• 2005

Soft tissue characterization and modeling based on living tissues has been investigated in order to provide a more realistic behavior in a virtual reality based surgical simulation. In this paper, we characterize the nonlinear viscoelastic properties of intra-abdominal organs using the data from in vivo animal experiments and inverse FE parameter estimation algorithm. In the assumptions of quasi-linear-viscoelastic theory, we estimated the nonlinear material parameters to provide a physically based simulation of tissue deformations. To calibrate the parameters to the experimental results, we developed a three dimensional FE model to simulate the forces at the indenter and an optimization program that updates new parameters and runs the simulation iteratively. The comparison between simulation and experimental behavior of pig intra abdominal soft tissue are presented to provide a validness of the tissue model using our approach.

• Biomedical Science Letters
• /
• v.11 no.1
• /
• pp.23-29
• /
• 2005

Molecular imaging with targeted contrast agents enables tissues to be distinguished by detecting specific cell-surface receptors. In the present study, a ligand-targeted acoustic nanoparticle system is used to identify angioplasty-induced expression of tissue factor by smooth muscle cell within carotid arteries. Pig carotid arteries were overstretched with balloon catheters, treated with tissue factor-targeted or a control nanoparticle system, and imaged with intravascular ultrasound before and after treatment. Tissue factor-targeted emulsion bound and increased the echogenicity and gray-scale levels of overstretched smooth muscle cell within the tunica media, versus no change in contralateral control arteries. Expression of stretch-induced tissue factor in carotid artery media was confirmed by immunohistochemistry. The potential for abnormal thrombogenicity of balloon-injured arteries, as reflected by smooth muscle expression of tissue factor, was imaged using a novel, targeted, nanoparticulate ultrasonic contrast agent.

• Journal of Biomedical Engineering Research
• /
• v.29 no.4
• /
• pp.255-266
• /
• 2008

In tissue engineering, scaffolds play an important role in the growth of cells to 3-D organs or tissues. For the success of tissue engineering, they should be mimicked to meet the requirements of natural extracellular matrix (ECM) in the body, such as mechanical properties, adhesiveness, porosity, biodegradability, and growth factor release, etc. Contrary to other materials, polymeric materials are adequate to engineer scaffolds for tissue engineering because controlling the structure and the ratio of components and designing various shapes and size are possible. In this review, the importance, major characteristics, processes, and recent examples of polymeric scaffolds for tissue engineering applications are discussed.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.32 no.4
• /
• pp.344-350
• /
• 2010

A progressive hemifacial atrophy is characterized by progressive atrophy of subcutaneous fat and rarely muscle and bone. Its contour follows the underlying muscle. Unilateral involvement is common. The treatment goal has been focused on the augmentation of the soft tissue. Many materials such as implants, collagen, fat graft, fat injection, dermal fat graft, filler and vascualized autogenous graft have been used. Although these materials have been used, the best treatment hasn't been achived. In severe cases underlying soft tissue, muscle and bone may be atrophied and massive soft tissue graft, implant and orthognathic surgery must be used. The author used the dermal-fat tissue for the pupose of soft tissue augmentation. We can get the massive soft tissue by the dermolipectomy procedure through the mini-abdominoplsty. The facial augmentation was done by augmentation of the dermal-fat tissue. The progressive hemifacial atrophy is hard to treat by only one procedure and many modalites must be considered.

• Journal of Korean Foot and Ankle Society
• /
• v.21 no.4
• /
• pp.165-169
• /
• 2017

Secondary soft tissue injuries can occur from the pressure of the displaced fragment of posterior calcaneal tuberosity in calcaneal tongue-type fractures and calcaneal tuberosity avulsion fractures. The soft tissue injury can be prevented by immediate reduction of the displaced fragments. Various techniques can be used to fix the fracture fragments, but the stability of fixation and minimal invasiveness to soft tissue should be considered. This paper reports the successful outcomes of patients with soft tissue compromises in calcaneal tongue-type fractures and calcaneal tuberosity avulsion fractures. The fixation technique of a large cannulated screw and simple cerclage wiring is believed to be a useful surgical option for the treatment of secondary soft tissue compromised calcaneal fractures.

• Fibers and Polymers
• /
• v.2 no.2
• /
• pp.51-57
• /
• 2001

Tissue engineering is one exciting approach to treat patients who need a new organ or tissue. A critical element in this approach is the polymer scaffold, as it provides a space for new tissue formation and mimics many roles of natural extra-cellular matrices. In this review, we describe several design parameters of polymer matrices that can significantly affect cellular behavior, as well as various polymers which are frequently used to date or potentially useful in many tissue engineering applications. Interactions between cells and polymer scaffolds, including specific receptor-ligand interactions, physical and degradation feature of the scaffolds, and delivery of soluble factors, should be considered in the design and tailoring of appropriate polymer matrices to be used in tissue engineering applications, as these interactions control the function and structure of engineered tissues.

• Archives of Reconstructive Microsurgery
• /
• v.19 no.1
• /
• pp.68-79
• /
• 2010

Lower abdominal tissue is regarded as an ideal donor site for the breast reconstruction because it provides large skin territory and huge amount of soft tissues enough to the breast size. However it is not easy for the surgeon to reconstruct the really natural breast, and needs the learning curve with long time experience. Author represent the various reconstruction procedures for the breast using lower abdominal tissue such as muscle sparing free TRAM, DIEP, and SIEA free flaps to reinsure like breast. Indications, and selection of reconstructive methods, surgical timing, selection of donor sites and recipient vessel of these flaps were reviewed. In addition, detailed procedures, surgical tips and secondary adjuvant procedures are described for more symmetry of reconstructed breast. The muscle sparing free TRAM, DIEP, and SIEA free flaps would be enough to provide supple, huge amount of well vascularized tissue for the breast, if these flaps were selected for the appropriate indication according to patient's general condition, obesity, the opposite breast and abdominal tissue condition. Lower abdominal tissue was able to provide versatile designs with sufficient adipose tissue without compromising the integrity of abdominal wall.

• Archives of Craniofacial Surgery
• /
• v.20 no.6
• /
• pp.408-411
• /
• 2019

Hairless scalp areas can occur due to trauma, tumors, or congenital disease. This aesthetically unpleasing condition can lead to psychosocial distress, and thin skin flaps may be prone to scarring. Treating the hairless scalp by simple excision is challenging because of skin tension. Tissue expanders are a good option for hairless scalp resurfacing. However, a single expansion may be inadequate to cover the entire defect. This report describes good results obtained using a serial resurfacing method involving re-expansion of the flap with a tissue expander to treat two patients with large lesions: one due to aplasia cutis congenital and another who underwent dermatofibrosarcoma protuberance resection. The results suggest that scalp resurfacing by serial tissue expansion using a tissue expander can be used for extensive lesions.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1458-1460
• /
• 2008

Tissue engineering is an interdisciplinary field that utilizes the principles of engineering and life sciences toward the creation of biological substitutes. Traditionally, major components of tissue engineering are cells, scaffolds, growth factors and recently biomechanical aspects have been given much attention. A large number of studies have reported that mechanical signals are of particular interest in either encouraging or inhibiting cellular responses. In tissue engineering, cell adhesion is a very important step, because quality of adhesion may determine a cell fate in the future. Elasticity of cell-adhesive substrate is found critical in regulating stem cell differentiation. Cells exert different contractile forces for cell migration, depending on substrate mechanics. Though tissue engineering is very interactive with diverse expertise, for a breakthrough, principles of biomechanics in tissue and cell level needs to be fully understood.

• Journal of Biomedical Engineering Research
• /
• v.17 no.2
• /
• pp.227-234
• /
• 1996

This paper is the study of the diffusion constant in order to calculate the percent oxygenation and percent blood volume using reflectance light within biological tissue. The diffusion constant play major role in percent oxygenation and percent blood volume and varies with the biological material such as hemolyzed blood, whole blood, dermis and epidermis in vivo tissue. The diffusion constant can be modeled to consist of a contribution from bloodless tissue and blood present in tissue. The reflectance light for experimental are red light of 660nm, infrared light of 880nm, green light of 569nm. The correlation between the diffusion constant and biological tissue was analyzed by the intensity of reflectance light at different depth within human limb. The reflectance light was changed in response to physiological changes within biological tissue. The data for diffusion constant were obtained at different depth beneath the surface of the skin and will be utilized to amen the percent oxygenation and percent blood volume.