• 대한기계학회논문집B
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• 제37권11호
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• pp.985-990
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• 2013

신부전 환자의 신장기능을 유지하는 방법의 일환으로서 사용되는 혈액 투석 시 동정맥루 문합각도에 따라서 혈액 유동상태의 양호가 결정된다. 지금까지의 연구는 CFD에 의한 것이 대부분이었으나 실험적 보고는 없다. 본 연구에서는 동정맥루의 혈류역학적 특성을 분석하기 위하여 PIV기법을 이용하였다. PIV실험을 위한 혈관모델의 문합부 각도는 $30^{\circ}C$로 정하였다. 유체역학적 상사를 만족시키기 위하여 Re수는 같게 하였고, 동맥부분에 밸브를 달아 개폐 정도를 조절하면서 PIV실험을 수행하였다. PIV 실험결과 분지부 부분에서 재순환유동이 발생되는 것을 볼 수 있었고, 동맥의 개폐 정도에 따라 전체적인 혈류속도의 변화가 나타났다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제45권6호
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• pp.332-342
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• 2019

Objectives: Socket grafting is vital to prevent bone resorption after tooth extraction. Several techniques to prevent resorption have been described, and various bone graft substitutes have been developed and used with varying success. We conducted this pilot study to evaluate the performance of nanohydroxyapatite (nHA) derived from chicken eggshells in socket preservation. Materials and Methods: This was a prospective, single center, outcome assessor-blinded evaluation of 23 sockets (11 patients) grafted with nHA and covered with platelet-rich fibrin (PRF) membrane as a barrier. Bone width and radiographic bone density were measured using digital radiographs at 1, 12, and 24 weeks post-procedure. Postoperative histomorphometric and micro-computed tomography (CT) evaluation were performed. The study protocol was approved by the Institutional Ethics Committee. Results: All patients had uneventful wound healing without graft material displacement or leaching despite partial exposure of the grafted socket. Tissue re-epithelialized with thick gingival biotype (>3 mm). Width of the bone was maintained and radiographic density increased significantly with a trabecular pattern (73.91% of sockets) within 12 weeks. Histomorphometric analysis showed 56.52% Grade 3 bone formation and micro-CT analysis revealed newly formed bone with interconnecting trabeculae. Conclusion: Use of a PRF membrane with nHA resulted in good bone regeneration in sockets. Use of a PRF membrane prevents periosteal-releasing incisions for primary closure, thereby facilitating the preservation of keratinized mucosa and gingival architecture. This technique, which uses eggshell-derived nHA and PRF membrane from the patient's own blood, is innovative and is free of disease transfer risks. nHA is a promising economic bone graft substitute for bone regeneration and reconstruction because of the abundant availability of eggshell waste as a raw material.

• 대한두개안면성형외과학회지
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• 제20권3호
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• pp.170-175
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• 2019

Background: Cryptotia is a congenital anomaly in which the upper part of the retroauricular sulcus is absent and buried underneath the temporal skin. Various surgical techniques have been reported for the correction of cryptotia following Kubo's V-Y plasty in 1933. Conventional methods using a local skin flap, skin grafting, tissue expansion, Z-plasty, and any of these combined approaches can result in skin deficiency of the upper auricle. The aim of this study was to develop a new method that improves cosmetic results and has fewer complications. Methods: This study involved four patients in whom five cryptotia deformities were corrected using V-Y plasty and Z-plasty. After elevation of the flap, acellular dermal matrix (ADM; MegaDerm) that was over 5 mm in thickness was applied to the cephalo-auricular angle and positioned to enhance the projection of the ear. Lastly, the flap was transposed to complete the repair. Results: Between January 2014 and February 2018, cryptotia correction with ADM graft was performed in four patients. None of the patients developed a recurrence of cryptotia, and there were no postoperative complications such as wound infection, seroma formation, and dehiscence. In addition, the procedures resulted in a favorable cosmetic appearance. Conclusion: Based on these findings, i.e., no recurrence and a favorable cosmetic result, when using an ADM graft, it is suggested that this technique could be an alternative method of cryptotia correction. It could also lessen donor-site morbidity when compared to autologous cartilage grafting and be more cost-effective than using cartilage from a cadaver.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제17권2호
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• pp.130-136
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• 1995

Vestibuloplasty are following categories : Mucosal advancement(submucous), secondary epithlization(reepithelization) and grafting vestibuloplasty. Although certain procedures are indicated for alveolar bone loss and sulcus shortening, relapse can occur. Every efforts to minimize or compensate for it is controversy. O'Steen(1970) reported the mucous graft methods that none of vestibular shrinkage and graft contracture. 15patients in mucous graft vestibuloplasty with fibrin adhesive system(Beriplast) were taken in cases of alveolar bone resorption and mucosal shortening due to traumatized alveolar bone defects, senile atrophic alveolar bone, postoperative cyst or tumor resection, edentulous alveolar bone loss, and others. A technique in the use of small piece of palatal mucosa$(1{\times}20mm)$ from the lateral aspect of the palate with adhesive system provided to secure the skin grafts, avoid stent fixation, postoperative patient's comfort and less time-consuming than the standard technique, especially excellent bleeding control.

• 대한족부족관절학회지
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• 제9권2호
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• pp.193-196
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• 2005

A posterior 3-portal arthroscopic approach with the patient in the prone position provides a novel and optimal approach for isolated subtalar arthrodesis. This approach facilitates access to the posterior talocalcaneal facet and facilitates safe access with regard to the posteromedial neuromuscular bundle. The technique involves prone positioning, establishment of two posterolateral portals and one posteromedial portal, arthroscopic posterior talocalcaneal facet debridement, percutaneous morcellized bone grafting and internal screw fixation. Preliminary results have shown high patient satisfaction, an excellent fusion rate and less postoperative morbidity than open subtalar arthrodesis.

• 대한치과의사협회지
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• 제55권3호
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• pp.240-248
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• 2017

A keratinized gingiva is important to the natural teeth and it is more essential to the health of the peri-implant mucosa of the implants. There are various surgical methods to restore a keratinized gingiva. First, a clinician could utilize apically positioned flap operation. This flap operation technique could be used as a full or partial thickness. If there is little keratinized gingival tissue available for the apically positioned flap operation, free gingival grafting should be used. Its technique sensitivity is relatively high, but using various surgical techniques and disciplines makes it simple and have the good predictability. There have been many considerations for those surgical techniques. Clinicians who treat for periodontitis or operate implant surgeries have to know the considerations and surgical methods.

• Archives of Reconstructive Microsurgery
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• 제8권1호
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• pp.22-27
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• 1999

While the conventional end-to-end anastomotic technique is accepted as 'the golden standard' for microvascular anastomosis, it is time-consuming and tedious. In an effort to offer faster and safer ways of performing microvascular anastomoses, numerous anastomotic techniques have been proposed, but further refinements in microvascular techniques are still necessary. A 'continuous suture with interrupted knot' technique was devised for faster and safer anastomosis. It has been successfully used in microanastomoses of both artery and vein for free tissue transfer. It is a combination of the interrupted suturing technique and the continuous suturing technique. First, a continuous suture is made with the size of loop decreasing in order, and then the sutures are tied individually from the first loop to the last one as in the conventional interrupted suturing technique. It was applied clinically to fourteen patients over the past ten months and found to be a highly efficient technique that satisfied our needs. This 'continuous suture with interrupted knot' technique has several advantages over other techniques : The operative time is reduced comparing conventional interrupted suture technique. By delaying the tie and with the vessel walls kept separated, the risk of through-stitch can be reduced. Tying all the sutures at one time not only speed up the procedures, but also reduced the surgeon's fatigue. In addition, it has no problem of anastomotic stenosis which is a disadvantage of continuous suture technique. This technique proved to be faster and safer, and has patency equal to that of the conventional end-to-end anastomosis. It is of great help to the surgeon in reducing operative time, especially in clinical situations when many anastomoses are required, or lengthy grafting procedures are undertaken.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권4호
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• pp.306-313
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• 2009

Objectives: The aim of the present review was to evaluate survival rate and various factors associated with survival of osseointegrated implants. Patients and methods: The clinical comparisons were performed to evaluate survival rate of 794 endosseous implants that had been inserted between 2004 through 2008 in relation to sex and age of patients, position of implant, implant system and surface characteristics, length and diameter of implant, and bone graft technique. Results: The survival rate of implant was 94.3% in posterior area of maxilla and 98.6% in posterior area of mandible by position of implant, a statistically significant difference. As to diameter of implant, survival rate was 98.4% between the 4.0 and 4.5 mm and 75.0% in larger than 5.0 mm, that was statistically significant difference. There was a statistically significant difference regard to bone graft and surgical technique. The implant survival rate was 89.0% in a placement site which performed sinus lifting, and in case of implant placement with guided bone regeneration technique and without bone grafting was 97.6% and 100% each. Conclusion: According to these findings, this study establishes a relationship between survival rate of implant and position, surface characteristics, diameter of implant and bone graft technique.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권1호
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• pp.46-52
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• 2009

The maxillary posterior edentulous region presents unique and challenging conditions in implant dentistry. The height of the posterior maxilla is reduced greatly as a result of dual resorption from the crest of the ridge and pneumatization of the maxillary sinus after the loss of teeth. Materials previously used for sinus floor grafting include autogenous bone, allogeneic bone, xenogenic bone and alloplastic materials. Autogenous bone is the material of choice, but its use is limited by donor-site morbidity, complications, sparse availability, uncontrolled resorption and marked volume loss. One way to overcome this problem would be to use bone substitutes alone as a osteoconductive scaffold for bone regeneration from the residual bone or in combination with allogeneic bone, which also has osteoinductive properties. The purpose of this article is to describe a double layers technique of demineralized and mineralized bone graft materials instead of autogenous bone in sinus floor augmentation of deficient posterior maxillary alveolar process and to report our experience with this technique. Our results show that maxillary sinus augmentation using mineralized and demineralized bone materials, when installed simultaneously with the implant or not, is good results for bone healing.

• Journal of Chest Surgery
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• 제47권3호
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• pp.225-232
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• 2014

Background: Redo coronary artery bypass grafting (CABG) is still associated with increased morbidity and mortality as compared to the first-time operation. Further, the application of the off-pump technique to redo CABG is limited due to technical difficulties. The aim of this retrospective study was to analyze early and midterm results after redo CABG and compare the outcome of redo on-pump and off-pump CABG. Methods: From June 1996 to October 2011, elective redo CABG was performed in 32 patients. Mean age was 64.8 years (on pump 64.3 years vs. off pump 65.5 years; p=0.658), and 21 patients were male. Among these patients, 14 (43.8%) underwent on-pump CABG, and 18 (56.2%) underwent off-pump CABG. Results: Internal thoracic artery was used in 22 patients (68.8%), and total arterial revascularization was achieved in 17 patients (53.1%). The average number of distal anastomoses was 2.13, and the rate of incomplete revascularization was 43.8%. The rate of total arterial revascularization was higher in the off-pump group (14.3% vs. 83.3%, p<0.001), and the use of saphenous vein graft was more in the on-pump group (78.6% vs. 16.7%, p<0.001). Overall hospital mortality was 3.1% (n=1) and was comparable in both groups (on pump 7.1% vs. off pump 0%; p=0.249). Postoperative complications occurred in 9 patients (64.2%), and the rate of complications was high in the on-pump group without statistical significance (64.2% vs. 33.3%, p=0.082). The mean follow-up duration was 5.4 years, and overall survival at 10 years was $86.0%{\pm}10.5%$. There was no significant difference in the 10-year survival rate between the two groups (79.6% vs. 100%, p=0.225). Conclusion: Redo CABG can be safely performed with acceptable mortality. Redo off-pump coronary artery bypass is feasible with low mortality and morbidity, comparable target vessel bypass grafting, and long-term survival. The off-pump technique might be considered a safe option for redo CABG in high-risk patients.