Ultrafast optical switching and data encoding on synthesized light fields.

Modern electronics are founded on switching the electrical signal by radio frequency electromagnetic fields on the nanosecond time scale, limiting the information processing to the gigahertz speed. Recently, optical switches have been demonstrated using terahertz and ultrafast laser pulses to control the electrical signal and enhance the switching speed to the picosecond and a few hundred femtoseconds time scale. Here, we exploit the reflectivity modulation of the fused silica dielectric system in a strong light field to demonstrate the optical switching (ON/OFF) with attosecond time resolution. Moreover, we present the capability of controlling the optical switching signal with complex synthesized fields of ultrashort laser pulses for data binary encoding. This work paves the way for establishing optical switches and light-based electronics with petahertz speeds, several orders of magnitude faster than the current semiconductor-based electronics, opening a new realm in information technology, optical communications, and photonic processor technologies.

Attosecond electronic delay response in dielectric materials.

The advancement in the attosecond field and the generation of XUV attosecond pulses has enabled the study of electron dynamics in the solid-state by high harmonic generation spectroscopy. Here, we introduce new all-optical attosecond metrology to study the light-field induced electron dynamics in dielectric systems. This new methodology is based on the phase transition of a dielectric material due to its interaction with a strong light field. Hence, the charge carriers undergo an inter- and intraband transition, causing a modification in the electronic structure, dielectric constant, and optical properties of the dielectric system. Consequently, the dielectric material experiences an adiabatic semi-metal phase transition due to the strong polarizability. Therefore, the reflectivity of the dielectric system changes, following the shape of the pump field. Accordingly, the time-resolved reflectivity change measurement provides direct access to the phase transition and the related electronic dynamics of the system in real-time. In the reported experiment, a strong light field (pump pulse) induces the phase transition and modifies the fused silica sample's reflectivity, which is probed by another weak light field (probe pulse). The reflected probe beam spectrum is acquired as a function of the time delay between the pump and probe pulses. This measurement shows that the real-time phase transition dynamic (and reflectivity change) follows the pump field shape. Moreover, the reflectivity measurements have been recorded at different pump field strengths performed under the same conditions. The reflectivity trace shows a retardation phase delay at a higher driver field strength. The delay response-retrieved from the recorded reflectivity traces-is in the order of a few hundred attoseconds. In addition, the results show that the delay response monotonically increases as the trigger field escalates. Furthermore, the reflectivity measurements have been acquired for another dielectric system (CaF2). The electronic delay response shows the same linear behavior increase as that of the SiO2 system. This work establishes a universal new attosecond metrology for measuring the electron dynamics and delay response in different materials.

Development and Validation of Scoring System to Predict Secondary Amputations in Free Flap Reconstruction.

Need for amputation is a potential complication when limb salvage is attempted. The present study aimed to develop a risk assessment tool to predict the risk of future amputation when counseling patients about their reconstructive options. METHODS: All patients undergoing a free flap lower extremity soft tissue reconstruction by the senior author from 2005 to 2019 were retrospectively identified. Patient's demographics, comorbidities, and technical aspects of the operation were extracted. Logistic regressions were used to create a predictive scoring system for future amputation. RESULTS: A total of 277 patients were identified. Of these patients, two-thirds (183) were used to derive the scoring system and one-third (94) were used to validate the score. In total, 25 of 183 patients (14%) underwent an amputation. A stepwise forward logistic regression identified age > 55 years, smoking, acute wound, aggressive fluid resuscitation intra-operatively, inability to use a superficial vein for drainage, and inability to use the posterior tibialis artery for anastomosis as independent predictors of need for future amputations. The beta co-efficients were used to create the scoring system, and the patients were categorized into mild, moderate, and severe risk based on their cumulative score. The validity of the scoring system was verified by using the one-third validation cohort. CONCLUSIONS: In patients undergoing free flap reconstruction of the lower extremity, the need for future amputation is 14%. The use of a scoring system can guide the surgeon's and patient's decision regarding limb salvage.

Telemedicine and Plastic and Reconstructive Surgery: Lessons from the COVID-19 Pandemic and Directions for the Future.

Telemedicine holds vast amounts of potential in changing the way outpatient plastic and reconstructive surgery is practiced. Before the coronavirus disease 2019 (COVID-19) pandemic, video conferencing was used by a small fraction of medical specialties. However, since the start of the pandemic, the Centers for Medicare and Medicaid Services and the largest private health insurance companies have relaxed regulations to allow the majority of specialties to use video conferencing in lieu of in-person visits. Most importantly, video conferencing minimizes patient and physician exposure in situations such as these, and decreases risk in the immunocompromised population. Video conferencing, which has been shown to be just as safe and efficacious in treating patients, offers the ability to follow up with physicians while saving travel time and travel-related expenses. This in turn correlates with increased patient satisfaction. Video conferencing also allows physicians to expand their reach to patients in rural areas seeking advanced professional advice. Incorporating video conferencing into existing practices will make for a more efficient practice, improve patient satisfaction, and decrease cost to patients and the health care system.

Abdominal Etching: Surgical Technique and Outcomes.

BACKGROUND: The ideal body is characterized by a muscular physique and defined anterior abdominal wall. Despite diet and exercise, many are unable to achieve this desired result. Liposuction with abdominal etching is used to achieve high-definition abdominal aesthetics. The etching technique is performed with liposuction in a superficial plane, to create indentures consistent with "six-pack abs," or definition of vertical abdominal lines. METHODS: The authors' abdominal etching preoperative markings, surgical technique, and postoperative care are discussed. The surgeons' experience with abdominal etching in 50 consecutive patients is reviewed, including rate of complications and patient satisfaction. RESULTS: The average patient age was 36.4 years. We had an almost equal number of men (n = 26) and women (n = 24), with an average body mass index of 26.7 kg/m. The average blood loss was 275 ml, the average tumescence was 6 liters, and the average lipoaspirate was 5 liters. There were no major complications such as fat embolus, deep venous thrombosis, or intraabdominal injury. The most common minor postoperative complications were contour irregularities (12 percent), seromas (10 percent), and hyperpigmentation (2 percent). The majority of patients were satisfied (98 percent). The average length of postoperative follow-up was 27 months. CONCLUSIONS: Abdominal etching is a safe and effective method of creating a defined anterior abdominal wall for patients who desire the muscular definition of vertical abdominal lines. Almost all of our patients reviewed were satisfied with this procedure, maintained long-term results, and had an acceptable rate of complications. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Iatrogenic Conchal Defect Secondary to Auricular Cartilage Graft.

BACKGROUND: Cleft lip and palate are the most common craniofacial congenital malformations. Timing of the nasal repair remains somewhat controversial. Some authors perform a combined nasal and lip repair in infancy while others advocate for a staged repair with the nasal component occurring later in childhood. Frequently, secondary repair is needed to address residual nasal deformities in early adulthood. Conchal cartilage has become increasingly popular as a source of cartilage for secondary reconstruction. Donor site morbidities include hematoma formation, scar formation, and wound healing complications. To the best of the authors' knowledge, there is 1 previous report of a full through-and-through conchal defect as a complication of auricular cartilage graft harvesting. The authors report an infrequently described iatrogenic conchal defect due to cartilage harvesting managed with a single-stage reconstruction using bookend flaps. METHODS: A 19-year-old female with a history of unilateral cleft lip and palate repair underwent secondary rhinoplasty using conchal cartilage. A bolster dressing was applied to the conchal harvest site. The patient was unable to attend her postoperative clinic visit and was eventually seen 2 months postoperatively with the bolster still in place. A full-thickness conchal defect was present when the bolster was removed. RESULTS: A pressure dressing such as a bolster is commonly used to prevent hematoma formation after conchal cartilage graft harvesting. This is routinely removed during the initial postoperative visit. Prolonged placement can result in donor site complications such as a full-thickness conchal defect. CONCLUSION: A functional and aesthetic reconstruction of a full-thickness iatrogenic conchal defect was achieved with excellent results using a local posterior flap, and 2 anteriorly based bookend flaps for closure. To the best of the authors' knowledge, this report is the first to describe a single-stage reconstruction of an iatrogenic defect in the concha as a complication of conchal cartilage harvesting.

Panniculectomy Outcomes in Patients with End-Stage Renal Disease in Preparation for Renal Transplant.

PURPOSE: End-stage renal disease (ESRD) is associated with increased cardiovascular risk factors, electrolyte imbalances, and iron deficiency anemia. These factors may increase the risk of adverse outcomes in patients undergoing panniculectomy. There is a paucity of data regarding outcomes in patients with ESRD undergoing panniculectomy. The purpose of this study is to investigate whether ESRD is associated with increased rate of complications following a panniculectomy. METHOD: The Nationwide Inpatient Sample database (2006-2011) was used to identify patients who underwent a panniculectomy. Among this cohort, patients diagnosed with end-stage renal disease were identified. Patients excluded from the study were emergency admissions, pregnant women, patients less than 18 years old, and patients with concurrent nephrectomy or kidney transplants. Demographic factors, comorbidities, and postoperative complications were evaluated. Chi-squared and risk-adjusted multivariate logistic regression analyses were performed to determine whether end-stage renal disease was associated with increased rate of postoperative complications. RESULTS: A total of 34,779 panniculectomies were performed during the study period. Of these, 613 (1.8%) were diagnosed with ESRD. Patients with ESRD were older (mean age 58.9 vs. 49.3, p < 0.01) and more likely to have Medicare (63.5 vs. 18.4%, p < 0.01). They had higher rates of comorbidities, including diabetes, hypertension, congestive heart failure, chronic lung disease, chronic anemia, liver disease, peripheral artery disease, obesity, and coagulopathies (p < 0.01). The procedure was more likely to occur at a large, teaching hospital (p < 0.01). Postoperatively, patients with ESRD had a higher rate of death (3.3 vs. 0.2%, p < 0.01), wound complications (10.6 vs. 6.2%, p < 0.01), venous thromboembolism (4.9 vs. 0.8%, p < 0.01), blood transfusions (25.3% vs. 7.0%, p < 0.01), non-renal major medical complications (40.0% vs. 8.4%), and longer hospital stay (9.2 vs. 3.8 days, p < 0.01). Multivariate logistic regression analysis controlling for age, race, sex, hospital location/teaching hospital, payer, and all comorbidities demonstrated that ESRD was independently associated with increased venous thromboembolisms (OR 2.38, 95% CI 1.48-3.83) and non-renal major medical complications (OR 1.51, 95% CI 1.19-1.91). ESRD was not independently associated with increased rate of wound complications or transfusions. CONCLUSION: Patients with ESRD are at increased risk of VTE and non-renal major medical complications following panniculectomy. Moreover, patients with ESRD have longer hospital stays and higher rates of mortality. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Abdominal Contouring Outcomes in Class III Obesity: Analysis of the ACS-NSQIP Database.

BACKGROUND: Obesity may increase the risk of complications following abdominal contouring. The aim of this study is to evaluate panniculectomy outcomes in patients with class III obesity (BMI > 40 kg/m2). METHODS: The American College of Surgeon's National Surgical Quality Improvement Program ACS-NSQIP (2010-2014) was used to identify patients who underwent panniculectomy. Class III obesity patients were identified. Demographics, comorbidities and postoperative outcomes were evaluated. Risk-adjusted multivariate logistic regression analyses were performed to assess impact of class III obesity on panniculectomy outcomes. RESULTS: A total of 4497 panniculectomies were identified. Of these, 545 (12.1%) were performed in patients with class III obesity. This group was older (mean age 50.3 vs. 45.9, p < 0.01) with a higher proportion of men (23.4 vs. 12.4%, p < 0.01). Class III obesity group also had higher rates of comorbidities (p < 0.01). Postoperatively, class III obesity patients experienced much higher rates of wound complications (17.8 vs. 6.8%), sepsis (3.3 vs. 0.8%), venous thromboembolism (1.5 vs. 0.7%) and medical complications (6.4 vs. 1.8%), p < 0.05. Additionally, this group had higher rates of unplanned reoperation (9.2 vs. 3.7%) and 30-day readmissions (3.5 vs. 1.0%), p < 0.01. On risk-adjusted multivariate regression analyses, class III obesity was independently associated with increased risk of wound complications (OR 2.22, p < 0.01), sepsis (OR 3.53, p < 0.01), medical adverse events (OR 1.98, p < 0.05), unplanned reoperation (OR 1.62, p < 0.05) and 30-day readmission (OR 2.30, p < 0.05). CONCLUSION: Class III obesity patients are at significantly increased risk of adverse outcomes following abdominal contouring. Plastic surgeons should consider these risks for counseling and preoperative risk optimization. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .