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Deaminase-T7 RNA polymerase fusion (MutaT7) proteins are a growing class of synthetic biology tools used to diversify target genes during in vivo laboratory evolution. To date, MutaT7 chimeras comprise either a deoxyadenosine or deoxycytidine deaminase fused to a T7 RNA polymerase. Their expression drives targeted deoxyadenosine-to-deoxyguanosine or deoxycytidine-to-deoxythymidine mutagenesis, respectively. Here, we repurpose recently engineered substrate-promiscuous general deaminases (GDEs) to establish a substantially simplified system based on a single chimeric enzyme capable of targeting both deoxyadenosine and deoxycytidine. We assess on- and off-target mutagenesis, strand and context preference, and parity of deamination for four different MutaT7GDE constructs. We identify a single chimera that installs all possible transition mutations more efficiently than preexisting, more cumbersome MutaT7 tools. The optimized MutaT7GDE chimera reported herein is a next-generation hypermutator capable of mediating efficient and uniform target-gene diversification during in vivo directed evolution.
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Objective: In the United States, orthopaedic, general, and plastic surgery hand fellowship programs train hand surgeons. Currently, differences in the academic qualifications of hand surgery fellowship directors (HSFDs) are unknown. This study compares the academic qualifications of HSFDs by specialty. Methods: American Medical Association's Residency and Fellowship Database was queried for hand surgery fellowship training programs. Scholarly activity, academic characteristics, and training pedigrees were collected for each HSFD. Results: Ninety-two HSFDs (73 orthopaedic surgeons, 17 plastic surgeons, 2 general surgeons) were identified. Most were male (87%) and Caucasian (82%). Mean age was 55 ± 11 years and most were trained in orthopaedic surgery (80%). Ten percent of orthopaedic hand surgery fellowship programs were run by a plastic surgeon HSFD, which was greater than 0% of plastic surgery hand fellowship programs run by an orthopaedic surgeon HSFD (p < 0.05). Mean H-index was 15 ± 9 from an average of 57 ± 47 publications. Orthopaedic and plastic surgeon HSFDs had similar levels of scholarly activity (p > 0.05). Age correlated with higher H-index values (r = 0.38, p < 0.001). More plastic surgeon HSFDs were trained by their top five fellowship programs than orthopaedic surgeon HSFDs (65 vs. 27%, p < 0.05). Conclusion: Ultimately, HSFDs have strong research backgrounds and similar characteristics despite disparate training pathways. Women and racial minority groups are largely underrepresented among leadership positions at hand surgery fellowships. These benchmarks can help inform future diversity initiatives.
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Objective: Qualifications needed to achieve national leadership positions in hand surgery are poorly defined. This study compares the academic accomplishments, demographics, and training backgrounds of presidents elected to serve the American Society for Surgery of the Hand (ASSH) and the American Association for Hand Surgery (AAHS). Methods: The ASSH and AAHS provided names of elected Presidents (1990-2022, n = 64). Curriculum vitae and academic web sites were used to collect demographic, training, bibliometric, and National Institutes of Health (NIH) funding data of presidents. Results: Presidents were predominately male (95%), Caucasian (90%), and orthopaedic surgery residency-trained (66%). Only 9% were racial minorities (8% Asian, 2% Hispanic, and 0% African American). The average age at appointment was 59 ± 7 years old, which was an average of 23 years from completion of hand surgery fellowship. More presidents received plastic surgery residency training in AAHS than ASSH (50 vs. 19%). The most represented hand surgery fellowships were Mayo Clinic (14%), University of Louisville (11%), and Duke University (9%). Twenty-one presidents participated in a travel fellowship (33%). Thirty presidents served as Department Chair or Division Chief at time of election (47%). The average h-index was 34 ± 18 resulting from 164 ± 160 peer-reviewed manuscripts and was similar between the two organizations. Eleven presidents had NIH grant funding (18%) and there were no differences in procurement or funding totals between the two organizations. Conclusion: Presidents of American hand surgery societies obtain high levels of scholarly activity regardless of training specialty. Women and racial minorities remain underrepresented at the highest levels of leadership.
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Objective: Multiple pathways exist for hand surgery training in the United States. Plastic surgeons often select Orthopedic Hand Surgery Fellowships to complement their skills and bridge perceived deficiencies in bone and joint cases. This study aims to quantify the impact of this approach on operative hand experience. Materials and methods: Case logs were analyzed for plastic surgery residents and orthopaedic hand surgery fellows (2016-2017 to 2019-2020). Reported hand surgery cases were compared between residency and fellowship using Student's t-tests. In total, 606 plastic surgery residents and 393 orthopaedic hand surgery fellows were included in this study. One year of Orthopedic Hand Surgery Fellowship training afforded more than twice the volume of hand surgery cases than Plastic Surgery Residency training (886.1 ± 234.7 vs. 428.1 ± 147.2, p < 0.001). Results: Case categories with the greatest positive fold difference in case volume encountered during Orthopedic Surgery Hand Fellowship were tumor (138.2 ± 63.2 vs. 22.1 ± 11.8, p < 0.001), joint reconstruction (108.7 ± 21.6 vs. 18.8 ± 11.5, p < 0.001), nerve decompression (158.4 ± 63.1 vs. 53.0 ± 32.6, p < 0.001), Dupuytren's (18.4 ± 10.5 vs. 7.6 ± 6.4, p < 0.001), and fracture management (132.8 ± 21.7 vs. 59.6 ± 24.1, p < 0.001). Conclusion: Orthopedic Hand Surgery Fellowship training doubles the operative hand case volume encountered during Plastic Surgery Residency. Significant increases are especially encountered for select case categories including bone and joint cases.
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Significance: Over the past decade, machine learning (ML) algorithms have rapidly become much more widespread for numerous biomedical applications, including the diagnosis and categorization of disease and injury. Aim: Here, we seek to characterize the recent growth of ML techniques that use imaging data to classify burn wound severity and report on the accuracies of different approaches. Approach: To this end, we present a comprehensive literature review of preclinical and clinical studies using ML techniques to classify the severity of burn wounds. Results: The majority of these reports used digital color photographs as input data to the classification algorithms, but recently there has been an increasing prevalence of the use of ML approaches using input data from more advanced optical imaging modalities (e.g., multispectral and hyperspectral imaging, optical coherence tomography), in addition to multimodal techniques. The classification accuracy of the different methods is reported; it typically ranges from â¼70% to 90% relative to the current gold standard of clinical judgment. Conclusions: The field would benefit from systematic analysis of the effects of different input data modalities, training/testing sets, and ML classifiers on the reported accuracy. Despite this current limitation, ML-based algorithms show significant promise for assisting in objectively classifying burn wound severity.
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Burns , Skin , Humans , Optical Imaging/methods , Machine Learning , Algorithms , Burns/diagnostic imagingABSTRACT
OBJECTIVE: This study assessed the supply and demand for Pediatric Surgery training in the U.S. from 2008 to 2022. We hypothesized that in the Pediatric Surgery Match: match rates would increase over time; U.S. MD Graduates would have higher match rates than non-U.S. MD Graduates; and fewer applicants would match at one of their top fellowship choices. DESIGN: This was a retrospective cohort study of Pediatric Surgery Match applicants (2008-2022). Cochran-Armitage tests elucidated temporal trends and chi square tests compared outcomes by applicant archetype. SETTING: Accreditation Council for Graduate Medical Education (ACGME)-accredited Pediatric Surgery training programs in the United States and non-ACGME-accredited programs in Canada. PARTICIPANTS: A total of 1,133 applicants for Pediatric Surgery training. RESULTS: From 2008 to 2012, growth in the annual number of fellowship positions (34-43, 27% increase) exceeded growth in number of applicants (62-69, 11% increase) (p < 0.001). Over the study period, the applicant-to-training ratio peaked at 2.1 to 2.2 in 2017 to 2018 and decreased to 1.4 to 1.6 in 2021 to 2022. The annual match rate for U.S. MD Graduates increased from 60% to 68% (p < 0.05), but decreased from 40% to 22% (p < 0.05) for non-U.S. MD Graduates. In 2022, there was a 3.1-fold difference in match rates between U.S. MD and non-U.S. MD Graduates (68% vs 22%, p < 0.001). The percentage of applicants that matched at their first choice (25%-20%, p < 0.001), second choice (11%-4%, p < 0.001), and third choice (7%-4%, p < 0.001) fellowships decreased over the study period. The percentage of applicants that matched at their fourth choice to least desirable fellowship increased from 23% to 33% (p < 0.001). CONCLUSIONS: The demand for Pediatric Surgery training peaked in 2017 to 2018 and has decreased since. However, the Pediatric Surgery Match remains competitive especially for non-U.S. MD Graduates. More research is needed to understand barriers to matching into Pediatric Surgery for non-U.S. MD Graduates.
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Internship and Residency , Specialties, Surgical , Child , Humans , United States , Retrospective Studies , Education, Medical, Graduate , Accreditation , Fellowships and ScholarshipsABSTRACT
Introduction The progression of medical knowledge competency during surgical residency training is poorly understood. This study measures the acquisition of medical knowledge as orthopedic surgery residents advance during training and the impact of accreditation status on orthopedic in-training examination (OITE) performance. Methods Orthopedic surgery residents taking the OITE during 2020 and 2021 were included. Residents were grouped into cohorts by post-graduate year (PGY) and Accreditation Council for Graduate Medical Education (ACGME) accreditation status. Comparisons were made with parametric tests. Results Eight thousand eight hundred and seventy-one ACGME-accredited residents (89%) and 1,057 non-ACGME-accredited residents (11%) were evenly distributed by the PGY level (range, 19-21%). Residents in both ACGME- and non-ACGME-accredited residency programs had a significant increase in OITE performance at each PGY level (P<0.001). At ACGME-accredited programs, OITE performance increased from PGY1 (51%), PGY2 (59%), PGY3 (65%), PGY4 (68%), and PGY5 (70%) (P<0.001). There were progressively smaller percentage increases in OITE performance during accredited residency training (range, 2-8%), but this increase was linear in non-accredited residency training (range, 4%). At each PGY level, residents at accredited programs outperformed their counterparts at non-accredited programs (P<0.001). Conclusion OITE performance increases during residency training. Among ACGME-accredited residents, performance on the OITE progresses rapidly during junior years and plateaus during senior years. Residents in ACGME-accredited residency programs outperform their counterparts in non-accredited residency programs. More research is needed to understand optimal training environments that promote medical knowledge acquisition during orthopedic surgery residency.
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Plexiform schwannomas are rare, benign, neural crest-derived tumors that commonly occur in the hand and upper extremities. They may be sporadic or associated with neurofibromatosis type 2. Although previous literature has described plexiform schwannomas occurring in fingers, nerve and tendon sheaths, and intraosseous lesions, this is the first known case of a plexiform schwannoma of the thumb. This is a case of a growing, painless, subungual mass of the thumb in a 54-year-old patient. After surgical excision and subsequent immunohistochemical examination, the patient was diagnosed with a plexiform schwannoma. This highlights the importance of maintenance a broad differential before surgery and obtaining a proper diagnosis using histopathology.
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The complex cerebrovascular network is critical to controlling local cerebral blood flow (CBF) and maintaining brain homeostasis. Alzheimer's disease (AD) and neurological injury can result in impaired CBF regulation, blood-brain barrier breakdown, neurovascular dysregulation, and ultimately impaired brain homeostasis. Measuring cortical hemodynamic changes in rodents can help elucidate the complex physiological dynamics that occur in AD and neurological injury. Widefield optical imaging approaches can measure hemodynamic information, such as CBF and oxygenation. These measurements can be performed over fields of view that range from millimeters to centimeters and probe up to the first few millimeters of rodent brain tissue. We discuss the principles and applications of three widefield optical imaging approaches that can measure cerebral hemodynamics: (1) optical intrinsic signal imaging, (2) laser speckle imaging, and (3) spatial frequency domain imaging. Future work in advancing widefield optical imaging approaches and employing multimodal instrumentation can enrich hemodynamic information content and help elucidate cerebrovascular mechanisms that lead to the development of therapeutic agents for AD and neurological injury.
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Currently, little is known about the differences in medical knowledge acquisition between osteopathic and allopathic orthopedic surgery residents. The purpose of this study was to determine the relationship between Orthopaedic In-Training Examination (OITE) performance and training pathway in orthopedic surgery. This was a retrospective cohort study of all orthopedic surgery residents taking the OITE during the 2019-2020 academic year. Comparisons in OITE performance were made with parametric tests. A total of 4407 orthopedic surgery residents were in allopathic (86%) and osteopathic (14%) training programs. There was significant improvement in OITE performance between subsequent postgraduate year (PGY) levels among allopathic residents (P<.001). Among osteopathic residents, OITE performance increased between PGY1 and PGY4 (P<.001) but plateaued between PGY4 and PGY5 (P>.05). At the PGY1 level, osteopathic residents had higher OITE performance than allopathic residents (P<.001), but scores were equivalent at the PGY2 to PGY4 levels (P>.05). At the PGY5 level, allopathic residents had higher OITE performance than osteopathic residents (P<.001). Allopathic medical students scored higher on the Step 1 (248±19 vs 242±17, P<.001) and Step 2 (255±16 vs 250±15, P<.001) board examinations. Medical knowledge increases during orthopedic surgery residency. Disparities exist by training pathway, with osteopathic residents outperforming allopathic residents at the PGY1 level but then underperforming at the PGY5 level. Ultimately, this study provides insights into how resident promotion and training pathway impacts the acquisition of medical knowledge during orthopedic surgery residency. [Orthopedics. 2023;46(6):379-383.].
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Internship and Residency , Orthopedic Procedures , Orthopedics , Humans , Retrospective Studies , Educational Measurement , Orthopedics/education , Orthopedic Procedures/education , Clinical Competence , Education, Medical, GraduateABSTRACT
Targeted mutagenesis mediated by nucleotide base deaminase-T7 RNA polymerase fusions has recently emerged as a novel and broadly useful strategy to power genetic diversification in the context of in vivo directed evolution campaigns. Here, we expand the utility of this approach by introducing a highly active adenosine deaminase-T7 RNA polymerase fusion protein (eMutaT7AâG), resulting in higher mutation frequencies to enable more rapid directed evolution. We also assess the benefits and potential downsides of using this more active mutator. We go on to show in Escherichia coli that adenosine deaminase-bearing mutators (MutaT7AâG or eMutaT7AâG) can be employed in tandem with a cytidine deaminase-bearing mutator (MutaT7CâT) to introduce all possible transition mutations simultaneously. We illustrate the efficacy of this in vivo mutagenesis approach by exploring mutational routes to antibacterial drug resistance. This work sets the stage for general application of optimized MutaT7 tools able to induce all types of transition mutations during in vivo directed evolution campaigns across diverse organisms.
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Mutagenesis , Adenosine Deaminase/genetics , Escherichia coli/genetics , Escherichia coli Proteins/genetics , Mutation , Genetic TechniquesABSTRACT
INTRODUCTION: Promotion within academic surgery involves demonstrated excellence in administrative, clinical, and scholarly activities. The present study analyzes the relationship between scholarly and clinical productivity in the field of reconstructive microsurgery. METHODS: This is a retrospective cohort study of microsurgery fellowship directors (MFDs). Data on clinical productivity were obtained from the American Society for Reconstructive Microsurgery and scholarly productivity from Scopus. Outcomes were department annual free flap volume, number of publications, and h-index. Descriptive statistics were calculated, and nonparametric tests were used to compare continuous variables. RESULTS: Thirty-nine MFDs were included in this study. All were plastic surgery residency trained and 38% trained under the independent training pathway. Most underwent formal fellowship training in reconstructive microsurgery (89%). The top three microsurgery fellowships trained 37% of all MFDs. Twenty-five percent of MFDs trained at the institution where they ultimately became program director. Twenty percent of MFDs had an additional degree (4 MS, 2 PhD, and 1 MBA). The median number of annual free flaps performed per institution was 175 (interquartile range [IQR] 122). The median h-index was 17 (IQR 13) resulting from 48 (IQR 99) publications. There was a correlation between department annual free flap volume and h-index (r = 0.333, P = 0.038). CONCLUSIONS: There is a correlation between academic productivity of MFDs and the clinical productivity of their department. This study provides a benchmark for aspiring reconstructive microsurgeons.
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Internship and Residency , Plastic Surgery Procedures , Humans , United States , Retrospective Studies , Efficiency , Fellowships and Scholarships , BibliometricsABSTRACT
BACKGROUND: Adequate exposure to commonly performed procedures during physical medicine and rehabilitation (PM&R) residency is an important issue. OBJECTIVE: To assess temporal trends and variabilities in reported procedural volumes, including the number of residents achieving procedure minimum requirements as established by the Accredited Council for Graduate Medical Education (ACGME) PM&R Residency Review Committee. DESIGN: This was a retrospective cohort study of PM&R residents graduating from 2013-2014 to 2020-2021. Descriptive statistics were calculated for tracked procedures and compared over time with analysis of variance (ANOVA) tests. Variability was calculated as the procedure volume difference between the 90th and 10th percentile groups. SETTING: ACGME-accredited PM&R residency training programs. PARTICIPANTS: A total of 3231 PM&R residents graduating from 2014 to 2021. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Reported procedure volume and number of residents achieving minimum requirements. RESULTS: Total procedure volume increased over the study period (436 ± 225 to 523 ± 238, p = .013). The percentage of all procedures that were performed versus observed was stable over the study period (81%-77%, p = .234). Variability in total reported procedure volume remained stable over the study period. The percentage of PM&R residents not achieving minimum requirements ranged from 2% for peripheral joint injections to 22% for ultrasound in the contemporary training period. CONCLUSIONS: The volume of reported procedures has increased along with the number of PM&R residency programs and residents. Variabilities in total reported procedure volume were stable over time, but PM&R residents struggle to obtain minimum requirements for ultrasound procedures.
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Internship and Residency , Physical and Rehabilitation Medicine , Humans , Retrospective Studies , Education, Medical, Graduate/methods , Clinical CompetenceABSTRACT
BACKGROUND: The National Institutes of Health (NIH) remains one of the predominant sources of biomedical research funding in the United States, yet its impact on total hip and knee arthroplasty research is poorly understood. This study defines the portfolio of NIH funding for total joint arthroplasty (TJA) and the impact of orthopaedic surgeons on this portfolio. METHODS: The Research Portfolio Online Reporting Tools Expenditures and Results (RePORTER) database was queried for NIH grants that had been awarded for total hip and knee arthroplasty and total NIH funding from 2010 to 2020. Compound annual growth rates (CAGRs) were calculated. Funding totals were compared with those from 20 other clinical areas. The principal investigators (PIs) and grants were characterized, and comparisons were made with use of the Student t test. RESULTS: A total of 489 grants were awarded, totaling $181 million (CAGR of 10.3%). This was >3 times the growth rate for the total NIH budget (CAGR of 2.9%), which increased from $31.2 to $41.7 billion over the 11-year period. When compared with 20 other clinical areas, TJA received the least amount of NIH funding over that period. Alzheimer disease received the most funding ($12.1 billion, CAGR of 19.5%), and cerebral palsy received the penultimate amount of funding ($284 million, CAGR of 6.3%). The R01 grant mechanism was the predominant source (63.1%), and the Mayo Clinic (Rochester, Minnesota) received the most funding (9.7%). Departments of orthopaedic surgery were awarded the most funding (23.5%), yet only 20 orthopaedic surgeons were identified as PIs (16.0%). There were no significant differences in NIH funding totals by PI demographic and academic characteristics (p > 0.05), yet orthopaedic surgeons had among the highest Hirsch indices (h-indices) (p < 0.001). Funding supported clinical (63.5%), translational (19.3%), basic science (7.1%), and other types (10.1%) of research. The top areas with funding were postoperative complications (44.4%), postoperative pain management (17.6%), rehabilitation (15.1%), and implant design (12.4%). CONCLUSIONS: There is a paucity of orthopaedic surgeon representation among NIH grants awarded for TJA. Opportunities may exist for orthopaedic surgeons to collaborate in identified areas of clinical interest. Additional research is needed to understand the obstacles to obtaining NIH grant funding for orthopaedic surgeon PIs. CLINICAL RELEVANCE: Increasing the levels of funding from the NIH is a strategic priority for departments of orthopaedic surgery. Understanding levels of funding for clinical areas in total joint arthroplasty is critical to foster research and discovery support from the NIH.
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Biomedical Research , National Institutes of Health (U.S.) , United States , Humans , MinnesotaABSTRACT
Biochemical recurrence (BCR) following radical prostatectomy (RP) has a limited ability to predict prostate cancer (PC) progression, leading to overtreatment, decreased quality of life, and additional expenses. Previously, we established that one-third of men with BCR in our group experienced low-risk recurrences that were safely observed without treatment. Our retrospective cohort analysis of 407 BCR patients post RP validates the use of PSA doubling time (DT) kinetics to direct active observation (AO) versus treatment following RP. The primary outcome was no need for treatment according to the predictive value of models of ROC analysis. The secondary outcome was PC-specific mortality (PCSM) according to Kaplan−Meier analysis. A total of 1864 men underwent RP (June 2002−September 2019); 407 experienced BCR (PSA > 0.2 ng/dL, ×2), with a median follow-up of 7.6 years. In adjusted regression analysis, initial PSADT > 12 months and increasing DT were significant predictors for AO (p < 0.001). This model (initial PSADT and DT change) was an excellent predictor of AO in ROC analysis (AUC = 0.83). No patients with initial PSADT > 12 months and increasing DT experienced PCSM. In conclusion, the combination of PSADT > 12 months and increasing DT was an excellent predictor of AO. This is the first demonstration that one-third of BCRs are at low risk of PCSM and can be managed without treatment via DT kinetics.
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PURPOSE: The hand surgery fellowship match attracts applicants from general, plastic, and orthopedic surgery residency training. The purpose of this study was to understand recent trends in applications and match rates in the hand surgery fellowship match. METHODS: The National Resident Matching Program provided program and applicant data from the hand surgery fellowship match (2012-2020). The primary outcomes of interest were match rates and number of unfilled fellowship positions by specialty. Trends over time and comparisons of the percentage of unfilled spots by specialty were observed. RESULTS: The total number of applicants decreased from 199 to 188 (5.5% decrease), while the number of available positions increased from 150 to 177 (18.0% increase) during the study period. The increase in available positions was driven primarily by orthopedic fellowships, which increased from 124 to 149 (20.2% increase). The percentage of applicants that did not match to a hand surgery fellowship decreased from 24.6% in 2012 to 5.9% in 2020. United States graduates had higher match rates than non-United States graduates during each year, but this disparity narrowed over time. Most applicants matched at one of their top 3 choices (first choice, 33.3%; second choice, 12.9%; third choice, 7.9%). Applicants matching at their first choice increased from 28.1% in 2012 to 39.4% in 2020. Plastic surgery hand surgery fellowships had a higher rate of unmatched positions relative to orthopedic surgery fellowships (6.1% vs 2.2%). CONCLUSIONS: Match rates in the hand surgery fellowship match have increased because of an overall increase in training positions and decrease in applicants. More research is needed to understand disparities in match rates by specialty. CLINICAL RELEVANCE: The diverse training experiences of hand surgeons historically have been viewed as a strength for the specialty. Understanding recent trends in the hand surgery fellowship match by specialty can help future applicants and faculty anticipate likely match outcomes.
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INTRODUCTION: Higher case volumes correlate with improved outcomes in total joint arthroplasty surgery. The purpose of this study was to understand the effect of adult reconstruction fellowship training on reported case volume in a contemporary cohort of orthopaedic surgeons. METHODS: The Accreditation Council for Graduate Medical Education provided case logs for orthopaedic surgery residents and adult reconstructive orthopaedic fellows from 2017 to 2018 to 2020 to 2021. Reported case volumes for total joint arthroplasty surgeries were compared using Student t tests. RESULTS: One hundred eighty-three adult reconstructive orthopaedic fellows and 3,000 orthopaedic surgery residents were included. Residents reported more total hip arthroplasty cases (98.9 ± 30 to 106.1 ± 33, 7.3% increase, P < 0.05) and total knee arthroplasty cases (126.0 ± 41 to 136.5 ± 44, 8.3% increase, P < 0.05) over the study period. On average, fellows reported 439.6 total cases: primary total knee arthroplasty, 164.9 cases (37.5%); primary total hip arthroplasty, 146.8 cases (33.4%); revision total knee arthroplasty, 35.2 cases (8.0%); revision total hip arthroplasty, 33.0 cases (7.5%); unicompartmental knee arthroplasty, 4.4 cases (1.0%); and other, 55.0 cases (12.5%). Overall, adult reconstructive orthopaedic fellowship reported between 1.7- and 2.0-fold more joint arthroplasty cases during 1 year of fellowship training than 5 years of residency ( P < 0.001). DISCUSSION: Adult reconstructive orthopaedic fellowship training provides notable exposure to additional cases after residency training. The results from this study may inform prospective applicants on the effect of fellowship training in total joint arthroplasty and help establish benchmarks in case volume for independent practice.
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Internship and Residency , Orthopedics , Adult , Benchmarking , Education, Medical, Graduate , Fellowships and Scholarships , Humans , Orthopedics/educationABSTRACT
BACKGROUND: Spreading depolarizations (SDs) are self-propagating waves of neuronal and glial depolarizations often seen in neurological conditions in both humans and animal models. Because SD is thought to worsen neurological injury, the role of SD in a variety of cerebral insults has garnered significant investigation. Anoxic SD is a type of SD that occurs because of anoxia or asphyxia. Although asphyxia leading to a severe drop in blood pressure may affect cerebral hemodynamics and is widely known to cause anoxic SD, the effect of anoxic SD on peripheral blood pressure in the extremities has not been investigated. This relationship is especially important to understand for conditions such as circulatory shock and cardiac arrest that directly affect both peripheral and cerebral perfusion in addition to producing anoxic SD in the brain. METHODS: In this study, we used a rat model of asphyxial cardiac arrest to investigate the role of anoxic SD on cerebral hemodynamics and metabolism, peripheral blood pressure, and the relationship between these variables in 8- to 12-week-old male rats. We incorporated a multimodal monitoring platform measuring cortical direct current simultaneously with optical imaging. RESULTS: We found that during anoxic SD, there is decoupling of peripheral blood pressure from cerebral blood flow and metabolism. We also observed that anoxic SD may modify cerebrovascular resistance. Furthermore, shorter time difference between anoxic SDs measured at different locations in the same rat was associated with better neurological outcome on the basis of the recovery of electrocorticography activity (bursting) immediately post resuscitation and the neurological deficit scale score 24 h post resuscitation. CONCLUSIONS: To our knowledge, this is the first study to quantify the relationship between peripheral blood pressure, cerebral hemodynamics and metabolism, and neurological outcome in anoxic SD. These results indicate that the characteristics of SD may not be limited to cerebral hemodynamics and metabolism but rather may also encompass changes in peripheral blood flow, possibly through a brain-heart connection, providing new insights into the role of anoxic SD in global ischemia and recovery.
Subject(s)
Cerebral Cortex , Heart Arrest , Animals , Asphyxia/complications , Blood Pressure , Cerebrovascular Circulation/physiology , Heart Arrest/complications , Hypoxia , Male , RatsABSTRACT
SIGNIFICANCE: Spatial frequency domain imaging (SFDI) is a wide-field diffuse optical imaging technique for separately quantifying tissue reduced scattering (µs ' ) and absorption (µa) coefficients at multiple wavelengths, providing wide potential utility for clinical applications such as burn wound characterization and cancer detection. However, measured µs ' and µa can be confounded by absorption from melanin in patients with highly pigmented skin. This issue arises because epidermal melanin is highly absorbing for visible wavelengths and standard homogeneous light-tissue interaction models do not properly account for this complexity. Tristimulus colorimetry (which quantifies pigmentation using the L * "lightness" parameter) can provide a point of comparison between µa, µs ' , and skin pigmentation. AIM: We systematically compare SFDI and colorimetry parameters to quantify confounding effects of pigmentation on measured skin µs ' and µa. We assess the correlation between SFDI and colorimetry parameters as a function of wavelength. APPROACH: µs ' and µa from the palm and ventral forearm were measured for 15 healthy subjects with a wide range of skin pigmentation levels (Fitzpatrick types I to VI) using a Reflect RS® (Modulim, Inc., Irvine, California) SFDI instrument (eight wavelengths, 471 to 851 nm). L * was measured using a Chroma Meter CR-400 (Konica Minolta Sensing, Inc., Tokyo). Linear correlation coefficients were calculated between L * and µs ' and between L * and µa at all wavelengths. RESULTS: For the ventral forearm, strong linear correlations between measured L * and µs ' values were observed at shorter wavelengths (R > 0.92 at ≤659 nm), where absorption from melanin confounded the measured µs ' . These correlations were weaker for the palm (R < 0.59 at ≤659 nm), which has less melanin than the forearm. Similar relationships were observed between L * and µa. CONCLUSIONS: We quantified the effects of epidermal melanin on skin µs ' and µa measured with SFDI. This information may help characterize and correct pigmentation-related inaccuracies in SFDI skin measurements.
Subject(s)
Colorimetry , Skin , Epidermis , Humans , Optical Imaging/methods , Skin/diagnostic imaging , Skin PigmentationABSTRACT
INTRODUCTION: Prospective residents interested in hand surgery must decide to apply for hand surgery fellowships sponsored by different specialties. This study compares case volumes reported during plastic surgery and orthopaedic hand surgery fellowships. METHODS: The American Council for Graduate Medical Education case logs of accredited hand surgery fellowships were analyzed for hand surgery cases (2012 to 2013 to 2020 to 2021). The reported case volume was compared by specialty. Temporal trends were described, intrapathway variabilities calculated, and interpathway differences calculated with Student t -tests. RESULTS: Two hundred plastic surgery (13%) and 1,323 orthopaedic (87%) hand surgery fellows were included. The number of orthopaedic hand surgery fellowships increased from 58 in 2012 to 2013 to 70 in 2020 to 2021 (21% increase), whereas the number of plastic surgery fellowships was stable at 16. Orthopaedic hand surgery fellows reported more hand surgery cases (764 ± 22 versus 628 ± 226), arthroscopy cases (53 ± 54 versus 23 ± 38), and miscellaneous hand surgery cases (42 ± 23 versus 31 ± 18) than plastic surgery hand fellows. Plastic surgery hand fellows reported more cases in wound closure with graft, wound reconstruction with flap, nerve injury, and vascular repair. Overall, orthopaedic surgery offered more experience in 15 case categories (58%), while plastic surgery offered more experience in five case categories (19%). Six case categories (23%) had no difference between specialties. DISCUSSION: Although orthopaedic hand surgery fellowship affords more cases overall, plastic surgery hand fellowships have unique strengths in wound reconstruction with grafts and flaps, nerve injury, and vascular repair. Ultimately, results from this study create a benchmark to improve future training opportunities for hand surgery fellows and orthopaedic surgery residents.