• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.38 no.6
• /
• pp.337-342
• /
• 2012

Objectives: Implants connect the internal body to its external structure, and is mainly supported by alveolar bone. Stable osseointegration is therefore required when implants are inserted into bone to retain structural integrity. In this paper, we present an implant with a "wing" design on its area. This type of implant improved stress distribution patterns and promoted changes in bone remodeling. Materials and Methods: Finite element analysis was performed on two types of implants. One implant was designed to have wings on its cervical area, and the other was a general root form type. On each implant, tensile and compressive forces ($30N/m^2$, $35N/m^2$, $40N/m^2$, and $45N/m^2$) were loaded in the vertical direction. Stress distribution and displacement were subsequently measured. Results: The maximum stresses measured for the compressive forces of the wing-type implant were $21.5979N/m^2$, $25.1974N/m^2$, $29.7971N/m^2$, and $32.3967N/m^2$ when $30N/m^2$, $35N/m^2$, $40N/m^2$, and $45N/m^2$ were loaded, respectively. The maximum stresses measured for the root form type were $23.0442N/m^2$, $26.9950N/m^2$, $30.7257N/m^2$, and $34.5584N/m^2$ when $30N/m^2$, $35N/m^2$, $40N/m^2$, and $45N/m^2$ were loaded, respectively. Thus, the maximum stresses measured for the tensile force of the root form implant were significantly higher (about three times greater) than the wing-type implant. The displacement of each implant showed no significant difference. Modifying the design of cervical implants improves the strength of bone structure surrounding these implants. In this study, we used the wing-type cervical design to reduce both compressive and tensile distribution forces loaded onto the surrounding structures. In future studies, we will optimize implant length and placement to improve results. Conclusion: 1. Changing the cervical design of implants improves stress distribution to the surrounding bone. 2. The wing-type implant yielded better results, in terms of stress distribution, than the former root-type implant.

• Journal of Environmental Health Sciences
• /
• v.25 no.3
• /
• pp.58-63
• /
• 1999

Biodegradable films were prepared by solution blend method in the weight ratio of chitosan for the purpose of useful biomaterials. The possibility of biomaterials prepared from natural polymer as a skin substitute was evaluated by measuring biocompatibility. These films were inserts in the back of rat and their biodegradability was investigated by the film weight and hematology as a function of time for the biotransformation. The result of rat test showed that medium, high viscosity chitosan induced some suspects of inbiocompatibility in the tissue by goreign body reaction 48 and 72 hours after implantation. Also, we prepared the official burn ointment which is made by low viscosity chitosan. This burn ointment was covered on the skin wound of artificial burn and their effect of healing was investigated by the evaluation of the naked eye and hematological change as a function of time. The result of rats test showed that burn ointments made from chitosan was effective reductio of inflammation than negative group.

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.10
• /
• pp.1291-1298
• /
• 2010

The aim of this research was to investigate the dynamic changes of the level of total prolactin receptor (PRLR) mRNA and the short form prolactin receptor (S-PRLR) mRNA in skin of cashmere goats from the initiation of cashmere fibre growth to active growth. Eighteen half-sib wethers were allocated randomly to two groups. Melatonin implants were used in order to initiate growth of cashmere fibre before the normal time and reduce blood plasma prolactin (PRL) concentration. Real-time reverse transcription quantitative polymerase chain reaction (real-time PCR) was used to determine PRLR mRNA expression levels of skin from June to November. The results showed that, in Chinese Inner Mongolia cashmere goats, there were seasonal variations in expression of total PRLR mRNA in skin with levels decreasing from June to October. Synchronously, the cashmere fibre growth rate gradually increased during this period, but the expression levels of S-PRLR mRNA did not decrease along with seasonal variation from initiation to active growth of cashmere fibre. These results suggest that expression levels of S- PRLR mRNA might be involved in the process of cashmere growth. It was also possible that the change of alternative splicing of PRLR occurred in the skin of cashmere goats from proanagen to anagen.

• Journal of Yeungnam Medical Science
• /
• v.38 no.3
• /
• pp.175-182
• /
• 2021

Breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL) is a rare T-cell non-Hodgkin lymphoma characterized as CD30 positive and anaplastic lymphoma kinase (ALK) negative. In 2016, the World Health Organization declared BIA-ALCL as a new disease entity. The first case of BIA-ALCL was reported in 1997, and as of July 2019, the United States Food and Drug Administration had cited a total of 573 United States and global medical device reports of BIA-ALCL, including 33 deaths. In all clinical case reports, except for those with unknown clinical history, the patient had received at least one textured surface breast implant. Although the etiology is not yet clear, chronic inflammation has been proposed as a potential precursor to tumorigenesis. The most common presentation of BIA-ALCL is peri-implant fluid collection following aesthetic or reconstructive implantation with textured surface breast implants. It can be accompanied by breast swelling, asymmetry, pain, skin lesions, lymphadenopathy, and B-type symptoms. Most cases are detected on average 7 to 10 years after implantation. Diagnostic specimens can be obtained with fine-needle aspiration or biopsy. BIA-ALCL is CD30 positive, epithelial membrane antigen positive, and ALK negative. It can be cured with complete surgical excision at the T1-T3 stage.

• Archives of Plastic Surgery
• /
• v.32 no.1
• /
• pp.93-99
• /
• 2005

In spite of proper maneuver of total knee replacement arthroplasty, some patients suffer from skin necrosis just above the implant. From Mar. 2000 to Jan. 2004, the authors performed reconstruction of knee skin defects after total knee replacement athroplasty. Total 6 cases of flap surgery were performed and patients ranged between 43-years-old to 82-years-old. Rectus femoris perforator based reversed adipofascial flaps were used in 2 cases, medial gastrocnemius muscular island flaps were used in 2 cases and sural artery based on adipofascial rotation flap was used in 1 case. One patient with extended necrosis underwent reconstruction with dual flaps of sural artery based adipofascial rotation flap and medial gastrocnemius muscular island flap. There were no distinctive complication needing additional procedure in all cases during the long term follow up. Reconstruction of necrosis following total knee replacement arthroplasty had several characteristics different from simple knee defect. The patients might have the history of long term steroid usages, excessive skin tension due to implants, underlying disease such as diabetes, rheumatoid disease, and etc. In addition, the early ambulation is mandatory in these patients of total knee replacement arthroplasty. With regards to these special considerations, a single stage and reliable operation must be needed. The authors introduce various reconstruction methods and algorithm that may aid easy decision making.

• Archives of Craniofacial Surgery
• /
• v.19 no.2
• /
• pp.114-119
• /
• 2018

Background: The ideal absorbable plating system should provide sufficient rigidity and then be absorbed within a timely manner. The Resorb-X has been recently developed as a plating system with a mixture ratio of 50:50 poly(D, L-lactide). Methods: We present seven of 121 patients who experienced delayed degradation with this absorbable plate. One hundred twenty-one patients with facial bone fracture underwent surgical treatment from March 2011 to March 2015, and rigid fixation was achieved with the Resorb-X. Results: Of 121 patients, seven (5.8%) developed complications at the surgical sites. Six of 102 cases underwent fixation of the infraorbital rim and one of 73 underwent fixation of the frontozygomatic buttress; the other sites of fixation did not develop delayed degradation. Foreign body granuloma developed at the earliest by postoperative 20 months and at the latest by postoperative 28 months (average, 23.5 months). Conclusion: We observed that the use of absorbable plates in incision sites or areas with thin skin can increase the possibility of delayed degradation. When performing surgery in these areas, the normal skin above the fixed location should be covered sufficiently.

• Archives of Craniofacial Surgery
• /
• v.16 no.1
• /
• pp.24-28
• /
• 2015

Background: Acute auriculocephalic angle refers to an ear with helix that is spaced closely to the cranium. An increasing number of patients with acute auriculocephalic angle wish to undergo corrective operation for aesthetic purposes. However, there is a paucity of data regarding acute auriculocephalic angle. This paper proposes a treatment protocol for patients with acute auriculocephalic angle. Methods: We performed a retrospective analysis of patients undergoing acute auriculocephalic angle (4 patients, 6 ears). Patient records were reviewed for demographic data as well as auricular measurements at preoperative, immediate postoperative and final follow-up evaluations. Results: All of the patients were men with a mean age of 36.5 years (range, 23-52 years). The mean follow-up period was 47.5 months (range, 28-60 months). Postoperative auriculocephalic angle was close to the normal auriculocephalic angle ($25^{\circ}-30^{\circ}$) without notable scars. Moreover, the patients had minimal contractions of the skin flaps without any hematoma or relapse. Conclusion: We propose the following three treatment protocols for patients with acute auriculocephalic angle: the posterior auricular muscle should be sufficiently released, the mastoid area should be augmented using implants, the skin should be repositioned with a superior auricular flap.

• Macromolecular Research
• /
• v.15 no.3
• /
• pp.205-210
• /
• 2007

Collagen is the major structural protein of connective tissues. It can be used as a prosthetic biomaterial applicable to artificial skin, tendon, ligaments, and collagen implants. The objective of this study is to investigate the possibility of realizing wound dressing medical products by the synthesis of composite materials with collagen and a biodegradable polymer, PLLA, via a surface modification process. Type I collagen was obtained from pig skin by a separation process. The structural characteristics of the extracted collagen were confirmed by SDS-polyacrylamide (PAcr) gel electrophoresis (PAGE) and FTIR. Also, PLLA-g-PAcr was synthesized by the radical polymerization of acrylamide initiated by AIBN in the presence of PLLA. The surface of PLLA was modified by the presence of the acrylamide residues. The structural characteristics of the copolymer were analyzed by FTIR, $^1H-NMR$ and contact angle measurements. The water uptake and WVTR of the collagen/PLLA-g-PAcr composite tended to increase with increasing collagen concentration and with decreasing EDC concentration.

• IEIE Transactions on Smart Processing and Computing
• /
• v.4 no.3
• /
• pp.133-140
• /
• 2015

Neural stimulating implantable medical devices (IMDs) have been widely used to treat neurological diseases or interface with sensory feedback for amputees or patients suffering from severe paralysis. More recent IMDs, such as retinal implants or brain-computer interfaces, demand higher performance to enable sophisticated therapies, while consuming power at higher orders of magnitude to handle more functions on a larger scale at higher rates, which limits the ability to supply the IMDs with primary batteries. Inductive power transmission across the skin is a viable solution to power up an IMD, while it demands high power efficiencies at every power delivery stage for safe and effective stimulation without increasing the surrounding tissue's temperature. This paper reviews various wireless neural stimulating systems and their power management techniques to maximize IMD power efficiency. We also explore both wireless electrical and optical stimulation mechanisms and their power requirements in implantable neural interface applications.

• Archives of Plastic Surgery
• /
• v.37 no.1
• /
• pp.87-90
• /
• 2010

Purpose: Mondor's disease is commonly known as a benign breast condition after augmentation mammaplasty, and some authors have also reported its association with other breast surgeries such as reduction mammaplasty or axillary lymph node biopsy. Here we report two cases of Mondor's disease after immediate breast reconstruction with silicone implant. Methods: Two women, 51-year-old and 36-year-old, underwent immediate breast reconstruction with silicone implants after nipple-areolar skin-sparing mastectomy. Results: Subcutaneous cord-like firm lesion appeared on upper abdomen, axillary area following surgery. The lesion was painless and spontaneously subsided with no medications. Conclusion: To our knowledge, this is the first report of Mondor's disease developed after immediate breast reconstruction using silicone implant.