• International Journal of Vascular Biomedical Engineering
• /
• v.1 no.1
• /
• pp.41-47
• /
• 2003

The patency rates of small diameter vascular grafts are disappointing because of the formation of thrombus and intimal hyperplasia. Among the various factors influencing the success of graft surgery, the compliance and the size of a graft are believed to be the most important physical properties of a vascular graft. Mismatch of compliance and size between an artery and a graft alters anastomotic flow characteristics, which may affect the formation of intimal hyperplasia. Among the hemodynamic factors influencing the development of intimal hyperplasia, the wall shear stress is suspected as the most important one. The wall shear stress distributions are experimentally measured near the end-to-end anastomosis models in order to clarify the effects of compliance and diameter mismatch on the hemodynamics near the anastomosis. The effects of radial wall motion, diameter mismatch and impedance phase angle on the wall shear rate distributions near the anastomosis are considered. Compliance mismatch generates both different radial wall motion and instantaneous diameter mismatch between the arterial portion and the graft portion during a flow cycle. Mismatch in diameter seems to be affecting the wall shear rate distribution more significantly compared to radial wall motion. The impedance phase angle also affects the wall shear rate distribution.

• Journal of Periodontal and Implant Science
• /
• v.27 no.3
• /
• pp.549-559
• /
• 1997

The purpose of this study was to evaluate clinical changes in graft size after treatment with strip gingival autograft in human. 57 premolar teeth in 27 patients having the following mucogingival problems were selected. The width of extension, attached gingiva including free marginal gingiva, width of transplant and clinical sulcus depth were measured at the initial examination, 2, 12 and 24 weeks following the strip gingival autograft and free gingival autograft. The change of width of extension, attached gingiva including free marginal gingiva, width of transplant and clinical sulcus depth according to healing process in both graft procedures was statistically analyzed by repeated measure ANOVA test and independent t-test using SPSS program. The results were as follows : 1. The change of keratinized gingiva in both graft procedures was increased significantly at 24 weeks post-op. 2. The clinical sulcus depth exhibited no marked changes throughout the entire investigation in both graft procedures. 3. No dimensional variation was seen in graft size in both graft procedures. 4. Shrinkage did not differ significantly in both graft procedures. From the day of grafting to 24 weeks after surgery the percentages of shrinkage were : strip gingival autograft 28% and free gingival autograft 29%.

• Journal of Periodontal and Implant Science
• /
• v.38 no.3
• /
• pp.493-502
• /
• 2008

Purpose: The purpose of this study is to investigate on the regenerative capacity by using different size of graft materials around bony defect around implant. Material and Methods: Dental implant fixtures(Bio-TIS, Korea) were placed into the tibia of 8 rabbits. After placement of implant, artificial defects were created for each group, and the size of bone graft materials were used according to each designated group. 4 weeks after surgery, 8 rabbits were sacrificed. The histologic and histomorphometrical study were done for comparison of the regenerative capacity using $80-90{\mu}m$ and $200{\sim}1000{\mu}m$ size of grafting materials of OCS-$B^{(R)}$. Result: Matured bone formation was significantly increased more in Group E1($80-90{\mu}m$) than in Group E2($200{\sim}1000{\mu}m$). Group E1($80-90{\mu}m$) showed more significant augmentation in marginal length of graft material per unit area than Group E2($200{\sim}1000{\mu}m$). Group E1($80-90{\mu}m$) showed more interspace in graft material than Group E2($200{\sim}1000{\mu}m$). Control group showed no new bone formation around and inside of implanted fixture. Conclusion: Small grafting material size has great influence on bone regeneration.

• Archives of Plastic Surgery
• /
• v.38 no.1
• /
• pp.113-116
• /
• 2011

Purpose: Many fingertip injuries are associated with nail injury and it is hard to repair to original shape due to its unique characteristic. Mucosal graft is used for a defect of the nail bed injury. Hereby, we introduce a DAP flap and buccal mucosal graft, with which we could reduce the defect size of the injured fingertip and donor site morbidity at the same time, without any need for harvesting additional skin from other part of hand. Also, mucosal graft makes good cosmetic and functional outcome of nail. Methods: This method was performed in a 56-year-old man with fingertip injury on dorsal side of left thumb due to electrical saw. First, DAP flap was performed on the injured finger to reduce the size of the defect of fingertip and cover the bone exposure. Second, nail bed part of the DAP flap was de-epithelized and buccal mucosal graft was done from left side of intraoral cavity wall. Results: Flap and graft survived without any necrosis but some nail bed could not be covered with flap due to insufficient flap size. All wounds healed well and did not present any severe adversary symptoms. Conclusion: DAP flap with mucosal graft is an effective method that we can easily apply in reconstruction of fingertip injury. We suggest that the combination of the two procedures makes good functional and cosmetic outcome compared to the usual manner, especially in cases of nail bed injury without distal phalanx bone defect.

• Archives of Plastic Surgery
• /
• v.50 no.1
• /
• pp.106-115
• /
• 2023

Background Primary contraction of full-thickness graft has been traditionally quoted to be 40%. There are lacunae in literature to elaborate on the factors influencing it ever since. Methods About 75 subjects who underwent full-thickness grafting procedures to resurface small defects were included in the study. The initial and final graft dimensions after primary contraction were traced on X-ray templates and the percentage of contraction was evaluated using the graphical method. This was further correlated with age, collagen, elastic matrix metalloproteinases-1 (MMP-1) and -2 content along with dermal thickness of the skin specimen sent from the graft. Results The primary contraction of the graft had a very significant correlation only with the initial size of graft harvested with a linear regression of 33.3% and a Spearman's correlation of 0.587 significant at a p-value of 0.001. Conclusion This study though preliminary tries to highlight an important factor that primary contraction of grafts is a physical phenomenon independent of its contents like collagen, elastin, or MMP-1 and -2 or age and dependent on its initial size of harvest instead.

• Archives of Plastic Surgery
• /
• v.38 no.4
• /
• pp.451-457
• /
• 2011

Purpose: As a central feature of the face, the nose has considerable significance in appearance and expression. Reconstruction of full thickness defects of the nasal ala has always been a challenge because of the 3-dimensional structure. For reconstruction of post burn defects of ala, skin graft, local or pedicled flap and composite graft are optionally available. We have reconstructed the ala defects using adiposocutaneous graft and observed the outcome. Methods: From March 2003 to December 2010, 19 cases in 11 patients with scar contracture and defect on ala portion were performed operation using adiposocutaneous graft. As a donor site, we used the inguinal crease and posterior auricular area and the donor site was primarily closed. We made incision through the superior rim of ala and released fully. A graft is applied to recipient site with larger size than recipient volume. Results: The mean age of the patient was 38.6 years (16~51), males are seven patients and females are four patients. The operation was performed bilaterally in 5 patients and unilaterally in 6 patients. Composite grafts were harvested from inguinal area in 13 cases and posterior auricular area in 6 cases. In one case, we did 4 times of operation to get enough volume. All the grafts were well taken. The mean size of the graft was 3.63 $cm^2$. Conclusion: For reconstruction of post burn defects of ala, it's not easy to use local flap or pedicled flap because of hardness and fibrosis of surrounding tissue. So, we choose adiposocutaneous graft for ala deformity reconstruction, got satisfactory outcome in color matching and texture.

• International Journal of Vascular Biomedical Engineering
• /
• v.2 no.2
• /
• pp.10-15
• /
• 2004

Purpose: In the treatment of aortic aneurysm, endovascular stent-graft application has become an established method of treatment. To observe the outcomes of the procedure as the size change of aneurysm in relation with endoleak, a retrospective analysis was done for the consecutive cases who undertook the procedure. Materials & Method: Stent-graft was applied to the aortic aneurysm in 33 patients. The location of the aneurysm was thoracic in 11 patients and abdominal in 22 patients. CT angiographic was done for the follow-up evaluation to analyze the aneurysm size and the presence of endoleak. Results: Technical success rate was 97% (32/33). The primary success rate without endoleak was 84% (28/33). The secondary success was 90% (30/33). During the follow-up period of 3 months to 7years and 6months in 26 patients, a secondary endoleak developed in 5 cases. Post-implantation syndrome developed in 17 cases (51%). Among the 14 cases with follow-up imaging data for size, endoleak was negative in 10 cases. The aneurysm decreased in 5 cases, stable in size in 4 cases and enlarged in one case (10%).Among the 4 cases with endoleak positive, the aneurysm enlarged in two cases (50%). Conclusion: In the stent-graft application for aortic aneurysm, there is high chance of decrease of aneurysm size in those cases with endoleak negative. However, the aneurysm may increase and eventually rupture in the cases with en do leak positive. Close observation with CT angiography is necessary for the evaluation for the presence of endoleak and size change.

• Applied Chemistry for Engineering
• /
• v.20 no.3
• /
• pp.339-345
• /
• 2009

The graft copolymerization of acrylonitrile-EPDM-styrene (AES) was investigated under various reaction conditions such as the concentration of initiator, the content of diene and viscosity of EPDM, and the concentration of solvents. The conversion increased but the molecular weight and the rubber particle size decreased with the concentration of initiator. The graft ratio(GR) increased at low concentrations of the initiator but, after the maximum value, it gradually decreased with the concentration of initiator. Toluene as a single solvent gave the highest conversion and the mixture of ethyl benzene and toluene was better than toluene. The rubber particle size increased with the viscosity of EPDM and the graft ratio and the number of rubber particles with occluded SANs increased with the content of diene.

• Journal of Rhinology
• /
• v.25 no.2
• /
• pp.123-129
• /
• 2018

Background and Objectives: Endoscopic repair of cerebrospinal fluid (CSF) leak can avoid morbidity of open approaches and has shown a favorable success rate. Free mucosal graft is a good method, and multi-layered repair is more favorable. The inferior turbinate has been commonly utilized for the free mucosal graft, but we newly designed it as a bone-periosteal-mucosal composite graft for multilayered reconstruction. Subjects and Method: Four subjects with a skull base defect were treated with this method. The inferior turbinate was partially resected including the conchal bone and was trimmed according to defect size. Both bony parts and periosteum were preserved on the basolateral side of the mucosa as a composite graft. The graft was applied to the defect site using an overlay technique. Results: All cases were successfully repaired without any complications. Three of them had a defect size greater than 10-12 mm, and the graft stably repaired the CSF leakage. Conclusion: Endoscopic repair of CSF leakage using inferior turbinate composite graft is a simple and easy method and would be favorable for defect sizes greater than 10 mm.

• Journal of Periodontal and Implant Science
• /
• v.30 no.3
• /
• pp.639-650
• /
• 2000

The purpose of this study was to evaluate clinical changes in graft size after treatment with connective tissue autograft in human. 40 premolar teeth in 23 patients having the following mucogingival problemswere selected. The width of extension, attached gingiva including free marginal gingiva, width of transplant and clinical sulcus depth were measured at the initial examination, 2, 12 and 24 weeks following the connective tissue autograft and free gingival autograft. The change of width of extension, attached gingiva including free marginal gingiva, width of transplant and clinical sulcus depth according to healing process in both graft procedures was statistically analyzed by ANOVA test and independent ttest using SPSS program. The results were as follows : 1. The change of keratinized gingiva in both grafting procedures was increased significantly at 24 weeks post-op. 2. The clinical sulcus depth exhibited no marked changes throughoutthe entire investigation in both grafting procedures. 3 . After 12 weeks, no dimensional variation was seen in graft size in both grafting procedures. 4. Shrinkage differs significantly in both grafting procedures. From the day of graft to 24 weeks after surgery the percentages of shrinkage were connective tissue autograft 55% and free gingival autograft 29%.