Defect-Driven Configurational Entropy in the High-Entropy Oxide Li1.5MO3-δ.

Layered lithiated oxides are promising materials for next generation Li-ion battery cathode materials; however, instability during cycling results in poor performance over time compared to the high capacities theoretically possible with these materials. Here we report the characterizations of a Li1.47Mn0.57Al0.13Fe0.095Co0.105Ni0.095O2.49 high-entropy layered oxide (HELO) with the Li2MO3 structure where M = Mn, Al, Fe, Co, and Ni. Using electron microscopy and X-ray spectroscopy, we identify a homogeneous Li2MO3 structure stabilized by the entropic contribution of oxygen vacancies. This defect-driven entropy would not be attainable in the LiMO2 structure sometimes observed in similar materials as a secondary phase owing to the presence of fewer O sites and a 3+ oxidation state for the metal site; instead, a Li2-γMO3-δ is produced. Beyond Li2MO3, this defect-driven entropy approach to stabilizing novel compositions and phases can be applied to a wide array of future cathode materials including spinel and rock salt structures.

High-Entropy Spinel Oxide Ferrites for Battery Applications.

Four different high-entropy spinel oxide ferrite (HESO) electrode materials containing 5-6 distinct metals were synthesized by a simple, rapid combustion synthesis process and evaluated as conversion anode materials in lithium half-cells. All showed markedly superior electrochemical performance compared to conventional spinel ferrites such as Fe3O4 and MgFe2O4, having capacities that could be maintained above 600 mAh g-1 for 150 cycles, in most cases. X-ray absorption spectroscopy (XAS) results on pristine, discharged, and charged electrodes show that Fe, Co, Ni, and Cu are reduced to the elemental state during the first discharge (lithiation), while Mn is only slightly reduced. Upon recharge (delithiation), Fe is reoxidized to an average oxidation state of about 2.6+, while Co, Ni, and Cu are not reoxidized. The ability of Fe to be oxidized past 2+ accounts for the high capacities observed in these materials, while the presence of metallic elements after the initial lithiation provides an electronically conductive network that aids in charge transfer.

Chemical tools to expand the ligandable proteome: diversity-oriented synthesis-based photoreactive stereoprobes.

Chemical proteomics enables the global assessment of small molecule-protein interactions in native biological systems and has emerged as a versatile approach for ligand discovery. The range of small molecules explored by chemical proteomics has, however, been limited. Here, we describe a diversity-oriented synthesis (DOS)-inspired library of stereochemically-defined compounds bearing diazirine and alkyne units for UV light-induced covalent modification and click chemistry enrichment of interacting proteins, respectively. We find that these 'photo-stereoprobes' interact in a stereoselective manner with hundreds of proteins from various structural and functional classes in human cells and demonstrate that these interactions can form the basis for high-throughput screening-compatible nanoBRET assays. Integrated phenotypic analysis and chemical proteomics identified photo-stereoprobes that modulate autophagy by engaging the mitochondrial serine protease CLPP. Our findings show the utility of photo-stereoprobes for expanding the ligandable proteome, furnishing target engagement assays, and discovering and characterizing bioactive small molecules by cell-based screening.

Outpatient Prescription Opioid Use following Discharge after Deep Inferior Epigastric Perforator Breast Reconstruction with and without an Educational Intervention.

BACKGROUND: There is limited evidence for appropriate postoperative opioid prescribing in autologous breast reconstruction. We sought to describe postoperative outpatient prescription opioid use following discharge after deep inferior epigastric perforator (DIEP) breast reconstruction with and without an educational video. METHODS: Patients undergoing DIEP reconstruction were given a 28-day postoperative pain and medication logbook from August 2022 to June 2023. Our practice implemented an educational video upon discharge on proper opioid consumption. Descriptive statistics on patient characteristics, intraoperative and postoperative opioid consumption, and outpatient prescription opioid use after discharge were compared between the two cohorts. RESULTS: A total of 53 logbooks were completed with 20 patients in the no video cohort and 33 in the video cohort. On average, the days to cessation of opiates was longer in the no video cohort (8.2 vs. 5.1 days, p = 0.003). The average number of oxycodone 5 mg equivalents consumed following discharge was 13.8 in the no video cohort and 7.8 in the video cohort, which was statistically significant (p = 0.01). Overall, the percentage of opioids prescribed that were consumed in the video cohort was 28.3% versus 67.1% in the no video cohort. CONCLUSION: For patients discharging home after DIEP reconstruction, we recommend a prescription for 12 oxycodone 5 mg tablets. With the use of an educational video regarding proper opioid consumption, we were able to reduce the total outpatient opioid use to 5 oxycodone 5 mg tablets following hospital discharge.

RNA m6A methylation in psychiatric disorders.

This comprehensive review introduces the features of m6A modification and its role in neuropsychiatric disorders. The research findings suggest that m6A modifications and their regulators play a critical role in the occurrence and development of major psychiatric disorders, especially Alzheimer's disease, affecting synaptic protein synthesis, subtype classification, immune infiltration, pathogenesis, and inflammatory infiltration. These findings highlight m6A regulators as potential new diagnostic and therapeutic targets, with m6A methyltransferase METTL3 being the best-characterized regulator in these diseases. The review concludes that m6A modification is a promising target for the prevention and treatment of major psychiatric disorders.

Mixoplankton and mixotrophy: future research priorities.

Phago-mixotrophy, the combination of photoautotrophy and phagotrophy in mixoplankton, organisms that can combine both trophic strategies, have gained increasing attention over the past decade. It is now recognized that a substantial number of protistan plankton species engage in phago-mixotrophy to obtain nutrients for growth and reproduction under a range of environmental conditions. Unfortunately, our current understanding of mixoplankton in aquatic systems significantly lags behind our understanding of zooplankton and phytoplankton, limiting our ability to fully comprehend the role of mixoplankton (and phago-mixotrophy) in the plankton food web and biogeochemical cycling. Here, we put forward five research directions that we believe will lead to major advancement in the field: (i) evolution: understanding mixotrophy in the context of the evolutionary transition from phagotrophy to photoautotrophy; (ii) traits and trade-offs: identifying the key traits and trade-offs constraining mixotrophic metabolisms; (iii) biogeography: large-scale patterns of mixoplankton distribution; (iv) biogeochemistry and trophic transfer: understanding mixoplankton as conduits of nutrients and energy; and (v) in situ methods: improving the identification of in situ mixoplankton and their phago-mixotrophic activity.

Two-Dimensional Siloxene Nanosheets: Impact of Morphology and Purity on Electrochemistry.

Two-dimensional (2D) siloxene (Si6O3H6) has shown promise as a negative electrode material for Li-ion batteries due to its high gravimetric capacity and superior mechanical properties under (de)lithiation compared to bulk Si. In this work, we prepare purified siloxene nanosheets through the removal of bulk Si contaminants, use ultrasonication to control the lateral size and thickness of the nanosheets, and probe the effects of the resulting morphology and purity on the electrochemistry. The thin siloxene nanosheets formed after 4 h of ultrasonication deliver an average capacity of 810 mA h/g under a 1000 mA/g rate over 200 cycles with a capacity retention of 76%. Interestingly, the purified siloxene shows lower initial capacity but superior capacity retention over extended cycling. The 2D morphology benefit is illustrated where the parent siloxene nanosheet morphology and structure were largely maintained based on operando optoelectrochemistry, in situ Raman, ex situ scanning electron microscopy, and ex situ transmission electron microscopy. Furthermore, the purified siloxene-based electrode free from crystalline Si impurity experiences the least expansion upon (de)lithiation as visualized by cross-section electron microscopy of samples recovered post-cycling.

A Three-Step Method for the Preparation of N-Substituted 3,4-Dihydroisoquinolin-1(2H)-ones and Heteroaryl-Fused 3,4-Dihydropyridin-2(1H)-ones from 2-Bromobenzoate Precursors.

We demonstrate a general method for the preparation of diverse N-substituted 3,4-dihydroisoquinolin-1(2H)-one compounds through an overall three-step cross-coupling/cyclization/N-deprotection/N-alkylation sequence. In the first step, ethyl 2-bromobenzoates and 2-bromo-1-carboxyethyl heterocycles are cross-coupled with commercially available potassium (2-((tert-butoxycarbonyl)amino)ethyl)trifluoroborate to produce (hetero)aryl-substituted 3-[(N-Boc-2-carboxyethyl)phenyl]ethylamines. In a subsequent two-stage process, these (hetero)arylethylamines undergo base-mediated ring closure followed by N-deprotection and N-alkylation to produce N-substituted 3,4-dihydroisoquinolin-1(2H)-ones and heteroaryl-fused N-benzyl 3,4-dihydropyridin-2(1H)-ones. Mechanistic work was performed to elucidate the order of transformations for the latter two-stage process. The method was also extended to the production of N-benzyl isoindolin-1-one and N-benzyl 2,3,4,5-tetrahydro-1H-benzo[c]azepin-1-one.

A Nationwide Analysis Evaluating the Safety of Using Acellular Dermal Matrix with Tissue Expander-Based Breast Reconstruction.

Background In March 2021, the United States Food and Drug Administration (FDA) safety communication cautioned against the use of acellular dermal matrix (ADM) products in breast reconstruction and reiterated that the FDA does not approve ADM use in breast surgery. This study aims to assess the safety of ADM use in breast reconstruction. Methods Women who underwent ADM and non-ADM assisted tissue expander (TE)-based breast reconstruction were identified using the National Surgical Quality Improvement Program database (2012-2019). Trends of ADM use over time, and 30-day outcomes of surgical site infection (SSI), dehiscence, and unplanned reoperation were assessed. Results Of the 49,049 TE-based breast reconstructive cases, 42.4% were ADM assisted and 57.6% non-ADM assisted. From 2012 to 2019, the use of ADM increased from 26.1 to 55.6% (relative risk [RR] =1.10; p < 0.01). Higher rates of SSI (3.9 vs. 3.4%; p = 0.003) and reoperation (7.4 vs. 6.0%; p < 0.001) were seen in the ADM cohort. There was no significant difference seen in dehiscence rates (0.7 vs. 0.7%; p = 0.73). The most common reoperation within 30 days for the ADM group (17.6%) was removal of TE without insertion of implant (current procedural terminology: 11,971). ADM-assisted breast reconstruction was associated with increased relative risk of SSI by 10% (RR = 1.10, confidence interval [CI]: 1.01-1.21; p = 0.03) and reoperation by 15% (RR = 1.15, CI: 1.08-1.23; p < 0.001). Conclusions ADM-assisted breast reconstruction more than doubled from 2012 to 2019. There are statistically higher complication rates of SSI (0.5%) and reoperation (1.4%) with ADM use in TE-based breast reconstruction, suggesting that reconstruction without ADM is safe when comparing immediate postoperative outcomes.

Meshed Acellular Dermal Matrix for Two-Staged Prepectoral Breast Reconstruction: An Institutional Experience.

The introduction of acellular dermal matrix (ADM) to breast reconstruction has allowed surgeons to reexplore the prepectoral implant placement technique in postmastectomy breast reconstruction. Our institution adopted a novel approach using meshed ADM to lessen the financial burden of increased ADM utilization with the prepectoral breast reconstruction. This is a retrospective, single-center review of two-stage prepectoral breast reconstruction using meshed human-derived ADM for anterior prosthesis coverage. Patient demographics, oncologic data, perioperative characteristics, and complications were examined and reported as means with standard deviations. Cost-saving with the meshed technique was evaluated. Forty-eight patients (72 breasts) with a mean age of 48.5 ± 15.0 years (range 26-70 years) were included in the study. The mean follow-up time was 13.2 ± 4.4 months (range 4.1-25.8 months). Nineteen breasts (24.6%) experienced complications, with seromas being the most common complication (12.5%, n = 9). Expander removal and reoperation occurred at a rate of 8.3 and 9.7%, respectively. The average time to drain removal was 18.8 ± 6.6 days (range 8-32 days). Meshed ADM provided an average cost savings of $6,601 for unilateral and $13,202 for bilateral reconstructions. Our study found that human-derived meshed ADM can be safely used in two-staged prepectoral tissue expander-based breast reconstruction and can result in significant cost savings.

Smartphone Use for Patient Photography by Plastic Surgery Trainees.

Medical photography has become essential to patient care, trainee education, and research in highly visual specialties such as plastic surgery. As smartphone technology advances, plastic surgeons and trainees are using their personal smartphones to take medical photographs prompting ethical and legal concerns about patient consent and privacy. This study aims to determine the prevalence of personal smartphone use for patient photography among plastic surgery trainees, evaluate encryption practices, and establish understanding of current guidelines. Through a survey of 71 plastic surgery trainees throughout the United States, we show that 99% use their personal cell phone to take medical photographs while only 65% use HIPAA-compliant photo storage applications, and only 49% are aware of standard guidelines. This highlights that personal smartphone use among plastic surgery trainees is ubiquitous and there is a need for additional education and access to HIPAA-compliant photo storage applications.

Current Practices in the Pathologic Assessment of Breast Tissue in Transmasculine Chest Surgery.

BACKGROUND: No guidelines exist regarding management of breast tissue for transmasculine and gender-nonconforming individuals. This study aims to investigate the experiences and practices regarding perioperative breast cancer risk management among the American Society of Plastic Surgeons members performing chest masculinization surgery. METHODS: An anonymous, online, 19-question survey was sent to 2517 U.S.-based American Society of Plastic Surgeons members in October of 2019. RESULTS: A total of 69 responses were analyzed. High-volume surgeons were more likely from academic centers (OR, 4.88; 95 percent CI, 1.67 to 15.22; p = 0.005). Age older than 40 years [ n = 59 (85.5 percent)] and family history of breast cancer in first-degree relatives [ n = 47 (68.1 percent)] or family with a diagnosis before age 40 [ n = 49 (71.0 percent)] were the most common indications for preoperative imaging. Nineteen of the respondents (27.5 percent) routinely excise all macroscopic breast tissue, with 21 (30.4 percent) routinely leaving breast tissue. Fifty-one respondents (73.9 percent) routinely send specimens for pathologic analysis. There was no significant correlation between surgical volume or type of practice and odds of sending specimens for pathologic analysis. High patient costs and patient reluctance [ n = 27 (39.1 percent) and n = 24 (35.3 percent), respectively] were the most often cited barriers for sending specimens for pathologic analysis. Six respondents (8.7 percent) have found malignant or premalignant lesions in masculinizing breast specimens. CONCLUSIONS: Large variation was found among surgeons' perioperative management of chest masculinizing surgery patients regarding preoperative cancer screening, pathologic assessment of resected tissue, and postoperative cancer surveillance. Standardization of care and further studies are needed to document risk, incidence, and prevalence of breast cancer in the transmasculine population before and after surgery.

Photoacoustic imaging of posterior periodontal pocket using a commercial hockey-stick transducer.

SIGNIFICANCE: Photoacoustic imaging has shown advantages over the periodontal probing method in measuring the periodontal probing depth, but the large size of conventional photoacoustic transducers prevents imaging of the more posterior teeth. AIM: Our aim is to develop a photoacoustic imaging system to image the more posterior periodontal pocket. APPROACH: We report a clinical "hockey-stick"-style transducer integrated with fibers for periodontal photoacoustic imaging. Cuttlefish ink labeled the periodontal pocket as the photoacoustic contrast agent. RESULTS: We characterized the imaging system and then measured the pocket depth of 35 swine teeth. Three raters evaluated the performance of the hockey-stick transducer. The measurements between the Williams probing (gold standard) and the photoacoustic methods were blinded but highly correlated. We showed a bias of ∼0.3 mm for the imaging-based technique versus Williams probing. The minimum inter-reliability was over 0.60 for three different raters of varying experience, suggesting that this approach to measure the periodontal pocket is reproducible. Finally, we imaged three pre-molars of a human subject. We could access more upper and posterior teeth than conventional linear transducers. CONCLUSIONS: The unique angle shape of the hockey-stick transducer allows it to image more posterior teeth than regular linear transducers. This study demonstrated the ability of a hockey-stick transducer to measure the periodontal pocket via photoacoustic imaging.

Free Vascularized Fibula Salvage of Failed CPH in Pediatric Sarcoma Patients.

Background: Due to extended life expectancy and recent improvements in surgical techniques, limb salvage has replaced amputation as the gold standard and is now performed in 90-95% of upper extremity malignancies. However, many of these salvage procedures are associated with significant postsurgical complications. In particular, the clavicula pro humero (CPH) procedure is associated with high rates of nonunion. We present our experience with upper extremity salvage using the free vascularized fibular flap (VFF) after failure or nonunion of the original CPH procedure in the pediatric population. Methods: Five patients under the age of 18 diagnosed with upper extremity sarcoma who underwent tumor resection with immediate CPH reconstruction complicated with nonunion, and subsequent revision with free VFF were included. Data on patient demographics, oncologic characteristics, surgical procedures, intraoperative details, postoperative complications, and time to graft union were recorded. Results: Five patients (average age = 8.4 years; range = 5-10 years at surgery date) underwent secondary limb salvage procedure with free VFF reconstruction following failed CPH reconstruction for proximal humeral osteosarcoma (n = 4) or Ewing sarcoma (n = 1). The mean follow-up was 3.7 years. Complications occurred in five patients (100%), with three patients requiring reoperation (60%). Four patients achieved graft union (average union time = 3.7 months) and successful limb reconstruction. Four patients were alive with no local recurrence of the disease. One patient did not achieve union and was lost to follow-up. Conclusion: Primary bone tumors in the pediatric population require wide surgical resection, and reconstruction often has high complication rates that can warrant further procedures. A free VFF is a viable option for upper extremity salvage after previously failed reconstructions because it provides vascularized tissue to a scarred tissue bed and allows for the replacement or augmentation of large bony defects.

Hospitalization, mechanical ventilation, and case-fatality outcomes in US veterans with COVID-19 disease between years 2020-2021.

PURPOSE: Although veterans represent a significant proportion (7%) of the USA population, the COVID-19 disease impact within this group has been underreported. To bridge this gap, this study was undertaken. METHOD: A total of 419,559 veterans, who tested positive for COVID-19 disease in the Veterans Affairs hospital system from March 1st, 2020 to December 31st, 2021 with 60-days follow-up, was included in this retrospective review. Primary outcome measures included age-adjusted incidences and relative incidences of COVID-19 hospitalization, mechanical ventilation, and case-fatality outcomes. RESULTS: Of this veteran cohort with COVID-19 disease, predominately 85.7% were male, 59.1% were White veterans, 27.5% were ages 50-64, and 40.5% were obese. Although Black veterans were at 63% higher relative risk (RR) for hospitalization incidences, they had a similar risk RR for in-hospital deaths compared to the White-veteran referent. Asian, American Indian/Alaska Native races, advanced age ≥65, and the underweight were at high RR for mechanical ventilator and/or in-hospital deaths compared to respective referent groups. Veterans who are ≥85 years old had a nearly 5-fold higher incidence of death compared respective referent group. The monthly outcomes for hospitalization, ventilation, and case-fatality data showed decreasing trends with time. CONCLUSION: An increased incidence of death was associated with age ≥65 years and underweight veterans compared to the referent group. Age-adjusted data, however, did not show any increased incidence of death in Black veterans compared to White veterans. RATINGS OF THE QUALITY OF THE EVIDENCE: 3 (Case-control studies; retrospective cohort study).

Characteristics of Nonelderly Adult Health Care Persistent Super Utilizers in Utah.

In the United States, the top 1% and top 5% of health care spenders account for 23% and 50% of total health care spending, respectively. These high spenders have been coined the term super utilizers (SU). The aim of this study was to identify the characteristics associated with these patients to aid in developing public health interventions aimed at transitioning patients out of the SU category and thus ultimately helping to control health care costs. The authors utilized the Utah All-Payer Claims Database and Utah Population Database from 2013 to 2015 to identify demographics, comorbid conditions, health care utilization, and cost characteristics of persistent super utilizers (PSU) (≥3 hospitalizations per year for 3 years) of health care compared with persistent nonsuper utilizers (PNSU) (<3 hospitalizations per year for 3 years). Multivariable logistic regression was utilized to identify the characteristics associated with PSU versus PNSU. Higher outpatient/Emergency Department/noninpatient (eg, visits with imaging and Centers for Medicare & Medicaid Services preventive visits) health care utilization and spending, and prevalence of comorbid disease and psychosocial conditions were associated with PSU. In multivariable analysis, factors such as heart disease, chronic kidney disease (CKD), diabetes, alcohol abuse, and depression were statistically significantly associated with higher odds of PSU, with the most noteworthy being CKD (odds ratio [OR] 6.85, 95% confidence interval [95% CI] 5.84-8.02; P < 0.001), alcohol abuse (OR 5.90, 95% CI 4.49-7.69; P < 0.001), and heart diseases (OR 4.41, 95% CI 3.74-5.18; P < 0.001). The annual health care cost of a PSU is about 11.5 times greater than a PNSU ($54,776 vs. $4801; P < 0.001).

Transverse Rectus Abdominis Muscle Flow-Through to Free Fibula Flap for Lumbar Spinal Reconstruction in a Pediatric Patient: A Case Report.

CASE: A 7-week-old girl presented with a recurrent primitive myxoid mesenchymal tumor of infancy requiring extensive resection of lower back musculature, L3-S2 vertebral bodies, and left L5 nerve root. Reconstruction consisted of transverse rectus abdominis muscle (TRAM) flow-through to free fibular flap to reconstruct the bony defect and fill the soft-tissue void. One-year postoperative imaging revealed a well-incorporated fibula graft. At the 30-month follow-up, the patient can bear weight on the autograft while sitting upright, allowing for efficient ambulation with a wheelchair. CONCLUSION: TRAM flow-through to free fibular flap is an efficacious reconstructive method for a multilevel vertebral spinal defect in a pediatric patient.

An Analysis of the Modified Five-Item Frailty Index for Predicting Complications following Free Flap Breast Reconstruction.

BACKGROUND: The modified five-item frailty index is a validated and effective tool for assessing risk in surgical candidates. The authors sought to compare the predictive ability of the modified five-item frailty index to established risk factors for complications in free flap breast reconstruction. METHODS: The 2012 to 2018 American College of Surgeons National Surgical Quality Improvement Program database was queried for free flap breast reconstructive procedures. Univariate and multivariate regression analysis models were used to assess how modified five-item frailty index and factors commonly used to risk stratify (age, body mass index, American Society of Anesthesiologists classification, and history of smoking) were associated with complications. RESULTS: Of the total 10,550 cases, 24.1 percent experienced complications. A high modified five-item frailty index score is associated with a higher overall rate of postoperative complications (p < 0.001). This significant trend was demonstrated in both surgical (p < 0.001) and medical (p < 0.001) complications. When controlling for other risk factors commonly used for risk stratification such as age, body mass index, American Society of Anesthesiologists classification, and history of smoking, the modified five-item frailty index was significantly associated with medical (OR, 1.75; 95 percent CI, 1.37 to 2.22; p = 0.001) and any complications (OR, 1.58; 95 percent CI, 1.29 to 1.93; p < 0.001) and had the largest effect size. Assessing for specific complications, the modified five-item frailty index is the strongest independent predictor of reoperation (OR, 1.41; 95 percent CI, 1.08 to 1.81; p = 0.009). CONCLUSION: The modified five-item frailty index is a useful predictor of postoperative outcomes in patients undergoing free flap breast reconstruction when compared to other historically considered risk factors for surgical complications. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Big or small, patchy all: Resolution of marine plankton patch structure at micro- to submesoscales for 36 taxa.

Despite the ecological importance of microscale (0.01­1 meter) and fine-scale (1 to hundreds of meters) plankton patchiness, the dimensions and taxonomic identity of patches in the ocean are nearly unknown. We used underwater imaging to identify the position, horizontal length scale, and density of taxa-specific patches of 32 million organisms representing 36 taxa (200 micrometers to 20 centimeters) in the continental and oceanic environments of a subtropical, western boundary current. Patches were the most frequent in shallow, continental waters. For multiple taxa, patch count varied parabolically with background density. Taxa-specific patch length and organism size exhibited negative size scaling relationships. Organism size explained 21 to 30% of the variance in patch length. The dominant length scale was phylogenetically random and <100 meters for 64% of taxa. The predominance of micro- and fine-scale patches among a diverse suite of plankton suggests social and coactive processes may contribute to patch formation.

Management of Large Pediatric Wound Defects Using a Continuous External Tissue Expander.

Both internal and external tissue expanders take advantage of the innate adaptive mechanisms the skin exerts in response to mechanical tension, known as the stress-relaxation phenomenon. Internal tissue expander use is time-consuming and can be complicated by infection and extrusion. In this case series, continuous external tissue expanders used to manage large pediatric wounds were assessed. Fourteen patients (ages: 4 days to 17 years) with large wounds underwent continuous external tissue expansion intraoperatively. The success of wound closure was assessed. In addition, the size of the patient's wounds, duration of device application, and postoperative complications were evaluated. The continuous external tissue expander was applied to wound sizes ranging from 14.7 to 560 cm2 for 5 to 10 days until the wound was amenable for direct closure. In 11 of the 14 patients, delayed primary closure was achieved. The device significantly reduced the wound sizes of the remaining three cases (average 80% size reduction). There was no incidence of wound dehiscence or infection. This case series demonstrates the benefit of the continuous external tissue expansion in managing pediatric wounds that would not otherwise be amenable to primary closure. The method allows for timely closure with limited risk of infection or extrusion, and should be in the armamentarium of reconstructive plastic surgeons.