• Archives of Reconstructive Microsurgery
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• v.16 no.2
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• pp.57-62
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• 2007

Non-vascularized free composite graft is one of the simple and effective reconstructive options, but its clinical use has been limited due to questionable survival rate. Early vascularization is essential for graft survival and is mainly carried out via recipient bed or repaired sites. This study was designed to investigate the effect of the lateral marginal approximations on the survival of the free composite flap using a model of skin-subcutaneous composite graft in rats. Thirty 1.5 ${\times}$ 1.5 $cm^2$ sized square shape composite flaps were elevated freely and reposed in place immediately on the dorsum of five Sprague-Dawley rats, and divided into five groups of six flaps. In all groups, graft bed was isolated with silastic sheet. In the group I, all sides of flap were repaired with blockage of silastic sheet insertion. Three, two, and one sides of flap were treated with same method in the group II, III, and IV respectively. Other sides of flaps were repaired without blockage, so all sides of flap were repaired in the group V. At 14 days later, the survived rate of each flap was evaluated according to the numbers of the repair sites. Histological examination was done for the evaluation of new vessel development quantitatively. Overall survived rates were increased with the number of repaired sites, but the group V only showed increased survival rate up to more than fifty percentile of the flap size with a significant difference statistically. New vessels were also increased in proportion with the number of repaired sites, and the repair site more than two had significant effect on the increased number of new vessels. In conclusion, at least more than three-fourth of flap circumference should be repaired in order to increase flap survival effectively under the condition of bed isolation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.2
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• pp.94-99
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• 2017

Objectives: Idiopathic bone cavity (IBC) is an uncommon intra-osseous cavity of unknown etiology. Clinical features of IBC are not well known and treatment modalities of IBC are controversial. The purpose of this study was to investigate the clinical characteristics of 27 IBC patients who underwent surgical exploration. Materials and Methods: A total of 27 consecutive patients who underwent surgery due to a jaw bone cavity from April 2006 to February 2016 were included in this study. Nine male and 18 female patients were enrolled. Patients were examined retrospectively regarding primary site, history of trauma, graft material, radiographic size of the lesion, presence of interdental scalloping, erosion of the inferior border of the mandible, complications, results of bone graft, and recurrence. Results: Female dominance was found. Maxillary lesion was found in one patient, and bilateral posterior mandibular lesions were found in two patients. The other patients showed a single mandibular lesion. The posterior mandible (24 cases) was the most common site of IBC, followed by the anterior mandible (5 cases). Two patients with anterior mandibular lesion reported history of trauma due to car accident, while the others denied any trauma history. Radiographic cystic cavity length over 30 mm was found in 10 patients. Seven patients showed erosion of the mandibular inferior border. The operations performed were surgical exploration, curettage, and bone or collagen graft. One bilateral IBC patient showed recurrence of the lesion during follow-up. Grafted bone was integrated into the native mandibular bone without infection. One patient reported necrosis of the mandibular incisor pulp after operation. Conclusion: Differential diagnosis of IBC is difficult, and IBC is often confused with periapical cyst. Surgical exploration and bone graft are recommended for treating IBC. Endodontic treatment of involved teeth should be evaluated before operation. Bone graft is recommended to reduce the healing period.

• Archives of Plastic Surgery
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• v.32 no.5
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• pp.613-618
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• 2005

When a large peripheral nerve defect occurs, an autologous nerve graft is the most ideal method of recinstruction. But an autologous nerve graft has many limitations due to donor site morbidities. Many previous focused on finding the ideal nerve conduit. Among them, $Gore-Tex^{(R)}$ has several advantages over other conduits. It can be manipulated to a suitable size, does not collapse easily, and it is a semi- permeable material that contain pores. A round shaped nerve can be newly formed because of its smooth inner surface. The purpose of this study was to evaluate the availability of $Gore-Tex^{(R)}$ tube as a nerve conduit at the peripheral nerve defect in the rat sciatic nerve. The 10 mm nerve gap was made in each group. A $Gore-Tex^{(R)}$ tube filled with skeletal muscle was inserted and autologous nerve graft was harvested, respectively. In the experimental group, we placed a 0.5 mm thickness, $30{\mu}m$ pored, 1.8 mm in diameter and 14 mm length tube with skeletal muscle inserted inside. In the control group, the nerve gap was inserted with a rat sciatic nerve. We estimated the results electrophysiologically and histologically to 16 weeks postoperatively. Results in the nerve conduction velocity, total myelinated axon count, myelin sheath thickness and mean nerve fiber diameter, the experimental group was substantially lower than that of the control group, but the statistic difference was not significant (p<0.05). The morphology was very similar in both groups, microscopically. From the above results, We conclude that $Gore-Tex^{(R)}$ qualifies as an ideal nerve conduit. It is suggested that $Gore-Tex^{(R)}$ tube filled with skeletal muscle may, substitute for an autologous nerve graft.

• Journal of the Korean Burn Society
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• v.23 no.1
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• pp.20-24
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• 2020

Diabetic patients have an increased risk of burn injuries on foot. Because of their diabetic neuropathy, they could contact with hot water or warming device without being aware of it. Split-thickness skin graft (STSG) is successful in treatment of various wound types; however, donor site wounds are sometimes problematic, and complications such as pain and impaired healing often occur. Although, donor site wounds in healthy young individuals can rapidly heal without complications, the wound-healing capacity of elderly patients or those with a comorbidity has been reported to be low. The dermatome is the most commonly used tool because it can harvest a large skin graft in one attempt. However, it is difficult to harvest tissues if the area is not flat. Furthermore, because the harvested skin is usually rectangular, additional skin usually remains after skin grafting. Therefore, use of razor blade and fragmented STSG on a large defect area is advantageous for harvesting a graft with a desired size, shape, and thickness. From January 2018 to July 2018, fragmented STSG was used in 9 patients who suffered from burn induced open wound on foot with diabetic neuropathy. With this approach, healing process was relatively rapid. The mean age of patients was 70 (57~86 years) and all of 9 patients had diabetes mellitus type 2. In all patients, the skin graft on the defect site healed well and did not result in complications such as hematoma or seroma.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.1
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• pp.1-10
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• 2008

Purpose: This study was aimed to examine the resorption rate, the healing pattern, and the response of the surrounding tissue after the graft of the acellular dermal matrix ($AlloDerm^{(R)}$) and the autogenous dermis, and to report the clinical result of the use of $AlloDerm^{(R)}$ in order to restore the soft tissue defects. Methods: Twenty mature rabbits, weighing about 3 ㎏, were used for the experimental study. The $10\times10$ mm-size autogenous dermis and the $AlloDerm^{(R)}$ were grafted to the space between the external abdominal oblique muscle and the fascia of the rabbits. And the $AlloDerm^{(R)}$ was grafted to the pocket between the skin and the underlying perichondrium of rabbit ear. The resorption rate of the grafted sites was calculated, and the tissue specimens were histologically examined at 1, 2, 4, and 8 weeks after the graft. The five patients with the cleft-lip nasal deformity and the one patient with the saddle nose deformity, who received the $AlloDerm^{(R)}$ graft to restore the facial soft tissue defects, were reviewed for the clinical study. Results: The resorption rate at 8 weeks after the graft was 21.5% for the autogenous dermis, and 16.0% $AlloDerm^{(R)}$. In microscopic examinations, the infiltration of the inflammatory cells and the epidermal inclusion cyst were observed in the autogenous dermis graft. However, the neovascularization and the progressive growth of the new fibroblasts were shown in the $AlloDerm^{(R)}$ graft. And the six patients, who received the $AlloDerm^{(R)}$ graft, demonstrated the good stability of the grafts and improved appearance. There were no remarkable complications such as inflammation, rejection, dislocation, and severe absorption in the clinical cases. Conclusion: These results suggest that $AlloDerm^{(R)}$ can be an useful graft material for restoration of soft tissue defects because of the good stability and the tissue response without the remarkable clinical complications.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.6
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• pp.469-477
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• 2009

Purpose: This study was performed to evaluate the effect of various graft materials used with a titanium cap on the ability of new bone formation in the rabbit calvarium. Materials and Methods: A total of 32 sites of artificial bony defects were prepared on the calvaria of sixteen rabbits by using a trephine bur 8 mm in diameter. Each rabbit had two defect sites. 0.2 mm deep grooves were formed on the calvaria of sixteen rabbits by using a trephine bur 8 mm in diameter for the fixation of a titanium cap. The treatments were performed respectively as follows: without any graft for the control group (n=8), autogenous iliac bone graft for experimental group 1 (n=8), alloplastic bone graft ($SynthoGraft^{(R)}$, USA) for experimental group 2 (n=8), and xenogenic bone graft ($NuOss^{(R)}$, USA) for experimental group 3 (n=8). After the treatments, a titanium cap (8 mm in diameter, 4 mm high, and 0.2 mm thick) was fixed into the groove. At the third and sixth postoperative weeks, rabbits in each group were sacrificed for histological analysis. Results: 1. In gross examination, the surgical sites showed no signs of inflammation or wound dehiscence, and semicircular-shaped bone remodeling was shown both in the experimental and control groups. 2. In histological analysis, the control group at the third week showed bone remodeling along the inner surface of the cap and at the contact region of the calvarium without any specific infiltration of inflammation tissue. Also, there was no soft tissue infiltration. Bone remodeling was observed around the grafted bone and along the inner surface of the titanium cap in experimental group 1, 2, and 3. 3. Histologically, all groups at the sixth week showed the increased area of bone remodeling and maturation compared to those at the third week. In experimental group 2, the grafted bone was partially absorbed by multi nucleated giant cells and new bone was formed by osteoblasts. In group 3, however, resorption of the grafted bone was not observed. 4. Autogenous bone at the third and sixth week showed the most powerful ability of new bone formation. The size of newly formed bone was in decreasing order by autogenous, alloplastic, and heterogenous bone graft. There was no statistically significant difference among autogenous, alloplastic, and heterogenous bones(p>0.05). Summary: This result suggests that autogenous bone is the best choice for new bone formation, but when autogenous bone graft is in limited availability, alloplastic and xenogenic bone graft also can be an alternative bone graft material to use with a suitably guided membrane.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.5
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• pp.410-417
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• 2006

The present study was aimed to compare the resorption rate and the histological change of the autogenous dermis and the artificial dermis (Terudermis$^{(R)}$) after the transplantation, and to report the clinical results of the use of Terudermis$^{(R)}$ in order to restore the soft tissue defect. Twenty mature rabbits, weighing about 2 kg, were used for the experimental study. The autogenous dermis and the Terudermis$^{(R)}$ size 1${\times}$1 cm were transplanted to the space between the external abdominal oblique muscle and the external abdominal oblique fascia of the each rabbits. They were divided into 4 groups (n=5 each) and gathered at 1, 2, 4, and 8 weeks after the transplantation. The resorption rate was calculated, and H-E stain was preformed to observe the histological changes. The chart review of the 17 patients who received Terudermis$^{(R)}$ graft to the facial soft tissue defects was conducted for the clinical study. The resorption rate at 8 weeks after the transplantation was 21.5% for the autogenous dermis, and 36.4% Terudermis$^{(R)}$. In microscopic examinations, the infiltration of the inflammatory cells and the epidermal inclusion cyst were observed in the autogenous dermis graft. The neovascularization and the progressive growth of the new fibroblast were shown in the Terudermis$^{(R)}$ graft. In clinical data of 17 patients, the size of the grafted Terudermis$^{(R)}$ was from 1.5$cm^2$ to 7.5$cm^2$ (average 3.5$cm^2$). Follow-up ranged from 5 to 25 months. Fourteen patients with cleft palate demonstrated stability of the graft and unremarkable complications. But unstability of the graft and the partial relapse were observed in three patients received the vestibuloplasty. These results indicate that Terudermis$^{(R)}$ can be available substitute of autogenous dermis because of the stability about resorption, the histocompatibility, and the unremarkable clinical complications.

• Journal of Biomedical Engineering Research
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• v.13 no.4
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• pp.339-352
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• 1992

A numerical simulation of the steady and pulsatile flow across the end-to-side anastomosis was performed In order to understand the role of flow dynamics in the preferential bevel opment of distal anastomotic intimal hyperplasla. The finite element technique was employed to solve two-dimensional unsteady pulsatile flow in that region. The results of the steady flow revealed that low shear stresses occur at the proximally occluded host artery and at the recirculation region in the Inner wall just distal to the toe region of the anastomosis. The nor- mal;zed wall shear rate was increased, as was the recirculation zone size in the host artery of the by-pass graft anastomosis, with increased anastomotic junction angle. In order to min imize the size of the low wall shear region which might result in the intimal hyperplasia in the by-pass graft anastomosis, a smaller anastomotic junction angle is recommended. The pulsatile flow simulation revealed flow that regions of low and ascillating mali shear do exist near the anastomosis as In the steady simulation. The shift of stagnation point depends on the pulsation of the flow. As the flow was accelerated at systole, the stagnation point moved downstream, disappered at early diastole and reappeared during late diastole. Low shear stress was also found along both walls of the occluded proximal artery. However, the diastolic flow behavior is quite different from the steady results. The vortex near the occluded artery moved downstream and inwardly during late systole, and disappeared during diastole. Recirculations proximal to the toe and heel regions were significant during diastole. Shear stress oscillation was found along the opposite wall. The results of the present study revealed that tow shear occurs at the proximally occluded host artery aud the recirculation region in the inner wall Just dlstal to the toe region of the anastomosis. The present study suggested that the regions of fluctuated wall shear stress wit flow separation is correlated with the preferential developing regions of anastomosis neointial fibrous hyperplasia.

• Archives of Plastic Surgery
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• v.37 no.1
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• pp.52-58
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• 2010

Purpose: The digital artery perforator flap was recently introduced and has been proven to be useful for reconstruction of various finger defects. Short operative time, less invasive surgery, and reliable flap circulation are the major advantages of this flap. The authors presented the clinical cases of the digital artery perforator flap and compared them with the distant flaps within a hand (thenar and hypothenar flaps) to reveal their differences. Methods: From May of 2006 to February of 2009, the authors performed reconstructions of finger defects with the digital artery perforator flaps in 10 patients as with the distant flaps within hand in 9 patients (7 thenar and 2 hypothenar flaps). In these two groups of the patients, flap size, use of skin graft, length of stay in hospital, healing time, complications were reviewed retrospectively and compared with statistical analysis (Student's t-test). Results: All flaps survived completely. The mean size of the perforator flap was $0.9{\times}1.9\;cm$ and the mean distant flap within a hand was $1.9{\times}2.0\;cm$. The use of skin graft was reduced in the perforator group because the donor site of the flap was closed primarily. The hospitalization period and healing time also reduced significantly in the perforator group. Minor complications (partial flap loss) were noted in small percentages in both groups but resolved with conservative management. Mean follow-up period was about 6 weeks. Conclusion: The digital artery perforator flap was smaller than the distant flap but its reconstruction of finger defects was reliable and comparable to the conventional distant flaps within a hand. This flap would be not only an alternative method but very useful in the management of various finger defects, because of ease of operative technique, less invasive surgery, decreased need of skin graft, and shorter period of hospitalization and healing time.

• Archives of Pharmacal Research
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• v.29 no.8
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• pp.712-719
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• 2006

In this study, we prepared core-shell type nanoparticles of a poly(DL-lactide-co-glycolide) (PLGA) grafted-dextran (DexLG) copolymer with varying graft ratio of PLGA. The synthesis of the DexLG copolymer was confirmed by $^1H$ nuclear magnetic resonance (NMR) spectroscopy. The DexLG copolymer was able to form nanoparticles in water by self-aggregating process, and their particle size was around $50\;nm{\sim}300\;nm$ according to the graft ratio of PLGA. Morphological observations using a transmission electron microscope (TEM) showed that the nanoparticles of the DexLG copolymer have uniformly spherical shapes. From fluorescence probe study using pyrene as a hydrophobic probe, critical association concentration (CAC) values determined from the fluorescence excitation spectra were increased as increase of DS of PLGA. $^1H-NMR$ spectroscopy using $D_2O$ and DMSO approved that DexLG nanoparticles have core-shell structure, i.e. hydrophobic block PLGA consisted inner-core as a drug-incorporating domain and dextran consisted as a hydrated outershell. Drug release rate from DexLG nano-particles became faster in the presence of dextranase in spite of the release rate not being significantly changed at high graft ratio of PLGA. Core-shell type nanoparticles of DexLG copolymer can be used as a colonic drug carrier. In conclusion, size, morphology, and molecular structure of DexLG nanoparticles are available to consider as an oral drug targeting nanoparticles.