Robotic Microsurgery Training for Robot Assisted Reconstructive Surgery

Purpose: Recent advances in robotic surgery have affected not only surgery for visceral organs but also head and neck cancer surgery and microsurgery. The authors intended to analyze and share experience gained from performing microanastomosis training in a new robotic surgery system. Methods: Robotic microanastomosis training was performed using Da Vinci Xi. The robot arm used two black diamond forceps, one Potts scissor, and one vision camera. First, basic robotic surgery skills were trained with Da Vinci Skill Simulator training. Actual microanastomosis practice was performed using artificial blood vessel, chicken wing and porcine leg. Results: Three simulation training sessions were performed and five vessel anastomosis were performed. A total of 8 vascular anastomosis were performed, and anastomosis for one vessel took 31-57 minutes. The number of sutures used was more than one initially due to suture material damage, but one suture was used after four anastomosis. In the anastomosis time analysis with porcine legs, the actual anastomosis process took 2 minutes 15 seconds±41 seconds per stitch. The vascular anastomosis interval took more time than vascular anastomosis itself due to robot arm change and camera movement. Conclusion: Robotic microsurgery training was not difficult process for surgeons who had undergone conventional microsurgery. However, more training was needed to replace the robot arm and move the camera. In the long term, mechanical improvements in diamond forceps and camera resolution were necessary. In order to master robotic microsurgery, surgeons must get used to robotic surgery system through simulation training.ope

Inlay graft of acellular dermal matrix to prevent incisional dehiscence after radiotherapy in prosthetic breast reconstruction

BACKGROUND: As the indications for postmastectomy radiotherapy expand, innovative solutions are required to reduce operative complications and reconstructive failure after prosthetic breast reconstruction. In this study, we investigated the effectiveness of acellular dermal matrix (ADM) inlay grafts in preventing postoperative wound dehiscence of irradiated breasts in the context of prosthetic breast reconstruction. METHODS: A retrospective analysis was conducted of 45 patients who received two-stage prosthetic reconstruction and radiotherapy following mastectomy. An ADM graft was placed beneath the incisional site during the second-stage operation in 19 patients using marionette sutures, whereas the control group did not receive the ADM reinforcement. Patient demographics and complications such as wound dehiscence, capsular contracture, peri-prosthetic infection, cellulitis, and seroma were compared between the two groups. RESULTS: During an average follow-up period of 37.1 months, wound dehiscence occurred significantly less often in the ADM-reinforced closure group (0%) than in the non-ADM group (23.1%) (P=0.032). There was no significant difference between the two groups in relation to other complications, such as capsular contracture, postoperative infection, or seroma. CONCLUSIONS: The ADM inlay graft is a simple and easily reproducible technique for preventing incisional dehiscence in the setting of radiotherapy after prosthetic breast reconstruction. The ADM graft serves as a buttress to offload tension during healing and provides a mechanical barrier against pathogens. Application of this technique may serve to reduce complications in prosthetic breast reconstruction after radiotherapy.ope

Soft Tissue Measurement Method Using Radiopaque Material on Cone-beam Computed Tomography: An Ex Vivo Validation Study

Purpose: The purpose of this study was to investigate the validity and reproducibility of a method based on cone-beam computed tomography (CBCT) technology for the visualization and measurement of gingival soft-tissue dimensions. Material and Methods: A total of 66 selected points in soft-tissue of the ex vivo head of an adult pig were investigated in this study. For the measurement of radiographic thickness (RT), wet softtissue surfaces were lightly covered with barium sulfate powder using a powder spray. CBCT was taken and DICOM files were assessed for soft-tissue thickness measurement at reference points. A periodontal probe and a rubber stop were used for the measurement of trans-gingival probing thickness (TPT). After flap elevation, actual thickness of soft-tissue (actual thickness, AT) was measured. Correlation analysis and intraclass correlation coefficients analysis (ICC) were performed for AT, TPT, and RT. Results: All variables were distributed normally. Strong significant correlations of AT with RT and TPT values were found. The two ICC values between TPT vs. AT and RT vs. AT differed significantly. Conclusion: Our results indicated that correlation of RT was stronger than that of TPT with AT. We concluded that soft tissue measurement with CBCT could be a reliable method, compared to the trans-gingival probing measurement method.ope

Complications of Injectable Soft Tissue Filler

Background : Soft tissue fillers have been used widely in recent years. As the use of filler increases, many complications have arisen. The complications should be prevented and if it occurs effective treatments are necessary to achieve a satisfying aesthetic result. In this article, we discuss the commonly used soft tissue filler and their complications. Methods : We divided the soft tissue filler into three groups according to its origin. The possible complications and management according to the kind of filler were reviewed. Results : Soft tissue fillers can be divided into autologous, biologic, and synthetic groups. Local reaction in the injection site is a common and minimal complication. Misplacement, allergic reaction, infection, and delayed granulomatous reaction can occur. Skin necrosis and visual impairment can occur. It is desirable to have proficiency of basic injection techniques such as aspiration before injection, injection with needle withdrawal, slow injection of small amount, using the blunt-tipped microcannula, pinching and tenting. Conclusions : Soft tissue filler is a simple and safe material to soft tissue augmentation. Clinicians should know about the property and complications of the commonly used fillers. Also clinicians should be well aware of preventing and treating the complications.ope

Case series of maxillary anterior bone augmentation with a novel biphasic calcium phosphate: a clinical and radiographic pilot study

The purpose of this pilot case series was to evaluate the clinical and radiographic outcomes of employing newly developed alloplastic biphasic calcium phosphate (BCP) in guided bone regeneration (GBR) for maxillary anterior peri-implant defects. Six peri-implant dehiscence defects were grafted with BCP. For all included treatment sites, clinical (defect width [DW] and defect height [DH]), radiographic (horizontal hard tissue thickness [HT]), patient discomfort, and early wound healing outcomes were evaluated. At reentry surgery, all surgical sites indicated a change in DW, DH, HT0, HT1, HT2, and HT3 from 4.08±1.39 mm to 1.13±1.76 mm, 3.57±1.42 mm to 0.58±1.09 mm, 2.18±0.66 mm to 1.50±0.53 mm, 2.11±0.57 mm to 1.73±0.28 mm, 2.22±0.54 mm to 1.75±0.26 mm, and 2.63±0.87 mm to 1.83±0.46 mm, respectively. Significant differences were discovered between paired DW and DH (p<0.05), whereas radiographic parameters had no significant differences. The severity of pain and swelling was 4.8±1.9 and 6.5±1.9, respectively, and the duration of pain and swelling was 4.5±3.8 and 5.8±2.9 days, respectively, according to early postoperative discomfort assessment. No adverse reactions occurred at any treatment site. In terms of clinical and radiographic outcomes, the newly developed BCP is acceptable biocompatible and suitable for the GBR of maxillary anterior peri-implant dehiscence defects within the limitations of this study.ope

Efficacy of quilting sutures and fibrin sealant together for prevention of seroma in extended latissimus dorsi flap donor sites

BACKGROUND: The extended latissimus dorsi flap is important for breast reconstruction. Unfortunately, donor site seroma is the most common complication of extended latissimus dorsi flap for breast reconstruction. Although using fibrin sealant in the donor site reduces the rate of seroma formation, donor site seroma remains a troublesome complication. The purpose of this study was to analyze the effectiveness of the combination of quilting sutures and fibrin sealant in the latissimus dorsi donor site for the prevention of seroma. METHODS: Forty-six patients who underwent breast reconstruction with extended latissimus flap were enrolled in the study. The patients received either fibrin sealant (group 1, n=25) or a combination of fibrin sealant and quilting sutures (group 2, n=21) in the extended latissimus dorsi donor site. Outcome measures were obtained from the incidence, volume of postoperative seroma, total drainage amount, indwelling period of drainage, and duration of hospital stay. RESULTS: The incidence of seroma was 76% in group 1 and 42.9% in group 2 (P=0.022). We also found significant reductions in seroma volume (P=0.043), total drainage amount (P=0.002), indwelling period of drainage (P=0.01), and frequency of aspiration (P=0.043). The quilting sutures did not affect the rate of drainage, tube reinsertion, or hospital stay. CONCLUSIONS: The use of quilting sutures combined with fibrin sealant on the latissimus dorsi flap donor site is helpful for reducing the overall seroma volume, frequency of aspiration, and total drainage amount. KEYWORDS: Mammaplasty, Seroma, Surgical flaps, Suture techniquesope

The traditional versus endoscopic-assisted latissimus dorsi harvest in oncoplastic surgery: A long term comparison of breast volume, aesthetics, and donor site outcomes

Background/objective: Volume replacement with the latissimus dorsi (LD) is an option for patients after partial mastectomy. Although potential benefits of using the endoscopic technique have been previously described, previous studies have not assessed long term volume and aesthetic outcomes compared to traditional methods. In this study, we aim to compare the endoscopic, latissimus only harvest to the traditional latissimus with skin paddle method. Methods: Eleven patients underwent breast reconstruction with the traditional LD flap harvesting method; 9 underwent endoscopically assisted LD flap reconstruction. The difference between preoperative and >1 year postoperative volumes were recorded. Patient satisfaction and surgeon-based observer assessment of the breast aesthetic and donor site scar were compared between the two techniques. Results: Compared to the traditional group, there was a significant mean volume reduction in the endoscopic group (70.3 vs 21.7 cc, p = 0.0023). Operative time was also longer in the endoscopic group than in the traditional group (368 vs 257 min, p < 0.001). In observer assessment criteria, the result of the donor site scar assessment was superior in the endoscopic group in terms of vascularity (p = 0.0038), relief (p = 0.0023), and pliability (p = 0.053). Conclusion: Patients' attitudes and feelings about the scar were better in the endoscopic group than in the traditional group. However, compared to the endoscopic group, the traditional group achieved a better breast cosmetic result and better retention of volume postoperatively, possibly due to incorporation of the skin flap and adipo-fascial tissue.ope

Association of visceral fat via epicardial fat thickness with bone mineral content in Korean Healthy Twin Study

학위논문 (석사)-- 서울대학교 보건대학원 : 보건학과, 2015. 2. 성주헌.Despite the detrimental effects of abdominal visceral fat on many cardiovascular and metabolic diseases, the relationship between abdominal visceral obesity and osteoporosis remains controversial. In the present study, we investigated the association between bone mass and abdominal fat estimated by echocardiographic epicardial fat thickness, which is a surrogate measure of abdominal visceral fat, anthropometric data, and regional fat mass (FM) measured by dual energy x-ray absorptiometry (DXA). A total of 1198 subjects (525 men, 460 premenopausal women, and 213 postmenopausal women) were selected from the Healthy Twin Study, a nationwide Korean twin and family study. Epicardial fat thickness was measured on the free wall of the right ventricle at end-systole from the parasternal long axis views. Total FM, regional FM, lean mass (LM), and bone mineral content (BMC) were measured by DXA. We performed multiple linear regression analysis with two models to determine the association between abdominal visceral obesity and osteoporosis. Age and height were included as covariates in Model 1. Past medical history and behavioral factors were included in Model 2. Epicardial fat thickness was positively associated with BMC in all three subgroups (men, premenopausal women, and postmenopausal women) in Model 1 and in Model 2. Trunk FM, waist circumference, and waist-to-hip ratio were also positively correlated to BMC in all three subgroups. Together, these findings suggest that abdominal visceral fat has a positive effect on BMC in the Korean population.I. Introduction II. Method Study design and population Measurement of epicardial fat thickness Measurement of anthropometric data and body composition Clinical information Statistical analysis III. Results IV. Discussion V. ReferencesMaste

주식시장과 노동시장에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 경영학과 경영학전공, 2015. 8. 조재호.This thesis consists of two essays on the financial and labor market. The first chapter studies how the elasticity of intertemporal substitution (EIS) influences labor market fluctuations in the labor search and matching model with both extensive and intensive margins of labor supply. With the curvature of utility, the countercyclical marginal utility of consumption induces the flow value of unemployment to be procyclical, and the stock returns to be countercyclical. The former effect reduces unemployment volatility by weakening wage rigidity. In contrast, the latter effect magnifies unemployment volatility by discounting higher future payoffs from hiring at a lower discount rate, if wages do not absorb all of productivity shocks. The higher EIS reduces the procyclicality of the flow value of unemployment, and reinforces the countercyclicality of the stock returns. We quantitatively show that a high level of the EIS is required to resolve the unemployment volatility puzzle. The second chapter investigates why the positive momentum profit does not exist in the Korean stock market by examining how stock prices respond to public news. Even though the entire set of stocks does not show positive post holding period returns, stocks with news headlines have significantly positive momentum profits, which are mainly driven by return drifts of bad performers with news. However, good performers with public news, as well as those without news, present return reversal in Korea, which is opposite to the case of the U.S.(see \cite{Chan2003}). This difference explains the absence of momentum in Korea. The asymmetric reaction of stock price to news is ignored by major theories on the momentum. Further analyses indicate that transactional frictions can be more plausible explanation for this phenomenon than the incentive of managers to disclose bad news slowly.Chapter 1 Flow Value of Unemployment, Stock Returns, and Unemployment Volatility 1 1.1 Introduction 2 1.2 Model 10 1.2.1 Search and Matching Frictions in the Labor Market 11 1.2.2 Households Decisions 13 1.2.3 Production and Firms Decisions 18 1.2.4 Bargaining on Hours Worked and Wages 21 1.2.5 Asset prices 25 1.2.6 Competitive Equilibrium 26 1.3 Numerical Solution and Parameterization 27 1.3.1 Computation 28 1.3.2 Calibration 29 1.4 Quantitative Results 34 1.4.1 Labor Market Moments 34 1.4.2 Wage Channel: Procyclical Flow Value of Unemployment 37 1.4.3 Discount Rate Channel: Countercyclical Stock Returns 41 1.4.4 Implications for the Elasticity of Intertemporal Substitution 45 1.5 Extensions and Robustness 47 1.5.1 Nash Wage Bargaining 48 1.5.2 Utility of Chodorow-Reich and Karabarbounis (2014) 53 1.5.3 Recursive Preference 56 1.5.4 Wage Bargaining Parameters 58 1.5.5 Fixed Component in Vacancy-Posting Costs 59 1.6 Conclusion 60 Chapter 2 Why is the Momentum Absent? - Stock Price Reaction to News in the Korean Stock Market 70 2.1 Introduction 71 2.2 Methodology 75 2.2.1 Event portfolio formation 76 2.2.2 Test procedure 77 2.3 Data and Descriptive Statistics 78 2.4 Profitability of the momentum strategy 85 2.5 Sources for non-existence of the momentum 88 2.5.1 Abnormal returns in the event portfolios 88 2.5.2 Discussion 95 2.6 Implications of asymmetric reaction of stock price to news 97 2.6.1 Stock price, news and firms size 97 2.6.2 Stock price, news, and share turnover 101 2.7 Conclusion 104 References 111 초 록 120Docto

Dimensional changes in reconstructed nipples: autologous versus prosthetic breast reconstruction

Purpose: The creation of the nipple-areola complex is the final stage in breast reconstruction and highly affects patient satisfaction. The neo-nipple is well known to shrink over time, particularly in the nipple projection. Currently, no reconstruction technique is clearly superior in terms of nipple size maintenance. We evaluated nipple size changes among several methods of breast mound reconstruction. Methods: Seventy-eight patients received nipple-areola complex reconstruction secondarily after breast reconstruction. C-V flap nipple reconstructions were performed using a free transverse rectus abdominis myocutaneous (TRAM) flap in 25 cases (TRAM group), a latissimus dorsi (LD) myocutaneous flap in 27 cases (LD group), and an implant in 26 cases (implant group). The circumference and projection of the neo-nipple were measured using a flexible ruler, immediately after reconstruction and average 10 months after surgery. Results: The overall circumference and projection at the final measurement were 91.43% ± 7.11% and 62.16% ± 21.55%, respectively, of immediate postoperative values. The change in circumference did not significantly differ among the 3 groups. In contrast, the change in projection was significantly worse in implant group compared to that in TRAM and LD groups. In addition, among the patients in implant group, greater inflation was significantly associated with greater decrease in the nipple projection. Conclusion: Breast mound reconstruction with autologous musculocutaneous flap techniques achieves better long-term maintenance of the neo-nipple projection compared to that achieved with expanded tissue and implantation. Considering the prospective loss of long-term nipple dimension, the preoperative design should be oversized in accordance with its origin in mound reconstruction.ope