The state of anatomical donation programs amidst the SARS-CoV-2 (Covid-19) pandemic.

The inclusion of human body dissection in anatomical science curricula has been described as a critical educational experience for the mastery of anatomical structures and concepts. To ensure that body donors are ethically acquired and suitable for anatomy education, Anatomical Donation Programs (ADPs) are tasked with the responsibility of acquiring body donors for basic and clinical science curricula. Considering the personal and institutional impact of SARS-CoV-2, a national survey was conducted to examine the current effect of the pandemic on ADP protocols, body donation, and the sustainability of ADPs in the United States (U.S.). Eighty-nine U.S. ADPs were identified and contacted for optional participation in a survey to assess the impact of the SARS-CoV-2 pandemic on their programs. Survey data were collected and managed using REDCap electronic data capture tools. Thirty-six ADPs (40.5% response rate) from the nine U.S. Divisions are represented in the survey results. Data were collected on ADP descriptions and demographics, SARS-CoV-2 impact on ADPs and protocols, and body donation and ADP sustainability. Almost all ADPs reported that the pandemic has affected their ADP operations in some way; however, the sustainability for the majority of ADPs appears likely and donor availability remains stable due to a proportional decrease in body donations and body donor requests. As the long-term impact on ADPs has yet to be determined, the authors plan to reevaluate the lasting impact of the SARS-CoV-2 pandemic on body donation, ADP sustainability, and anatomical science education throughout the year 2021.

Crossover Assessment of Intraoral and Cuffed Ventilation by Emergency Responders.

OBJECTIVES: A cuffed bag valve mask (BVM) is the most common device used by emergency medical responders to ventilate patients. The BVM can be difficult for users to seal around the patient's mouth and nose. An intraoral mask (IOM) with snorkel-like design may facilitate quicker and better ventilation particularly under austere conditions. METHODS: Both a BVM and IOM were utilized by 27 trained emergency medical technicians and paramedics to ventilate a lightly embalmed cadaver. Ventilation efficacy, workload, and usability were assessed for both devices across four study conditions. RESULTS: The IOM was superior to the BVM in delivered tidal volume ratio (measure of leak, p < 0.03) and minute ventilation (p < 0.0001). Workload, ergonomic and usability assessments indicated that the IOM facilitated gripping through the reduced hand interface size (p < 0.01), decreased user effort (p < 0.001), and reduced upper limb workload (p = 0.0088). CONCLUSIONS: In the assessed model, the IOM represented a better choice for airway management than the standard cuffed BVM. An emergency medical device that is intuitive, efficacious and less demanding has the potential to reduce responder stress and improve resuscitation efforts, especially during austere rescue and patient transport.

Stent Design Affects Femoropopliteal Artery Deformation.

BACKGROUND: Poor durability of femoropopliteal artery (FPA) stenting is multifactorial, and severe FPA deformations occurring with limb flexion are likely involved. Different stent designs result in dissimilar stent-artery interactions, but the degree of these effects in the FPA is insufficiently understood. OBJECTIVES: To determine how different stent designs affect limb flexion-induced FPA deformations. METHODS: Retrievable markers were deployed into n = 28 FPAs of lightly embalmed human cadavers. Bodies were perfused and CT images were acquired with limbs in the standing, walking, sitting, and gardening postures. Image analysis allowed measurement of baseline FPA foreshortening, bending, and twisting associated with each posture. Markers were retrieved and 7 different stents were deployed across the adductor hiatus in the same limbs. Markers were then redeployed in the stented FPAs, and limbs were reimaged. Baseline and stented FPA deformations were compared to determine the influence of each stent design. RESULTS: Proximal to the stent, Innova, Supera, and SmartFlex exacerbated foreshortening, SmartFlex exacerbated twisting, and SmartControl restricted bending of the FPA. Within the stent, all devices except Viabahn restricted foreshortening; Supera, SmartControl, and AbsolutePro restricted twisting; SmartFlex and Innova exacerbated twisting; and Supera and Viabahn restricted bending. Distal to the stents, all devices except AbsolutePro and Innova exacerbated foreshortening, and Viabahn, Supera, Zilver, and SmartControl exacerbated twisting. All stents except Supera were pinched in flexed limb postures. CONCLUSIONS: Peripheral self-expanding stents significantly affect limb flexion-induced FPA deformations, but in different ways. Although certain designs seem to accommodate some deformation modes, no device was able to match all FPA deformations.

Limb flexion-induced axial compression and bending in human femoropopliteal artery segments.

BACKGROUND: High failure rates of femoropopliteal artery (FPA) interventions are often attributed in part to severe mechanical deformations that occur with limb movement. Axial compression and bending of the FPA likely play significant roles in FPA disease development and reconstruction failure, but these deformations are poorly characterized. The goal of this study was to quantify axial compression and bending of human FPAs that are placed in positions commonly assumed during the normal course of daily activities. METHODS: Retrievable nitinol markers were deployed using a custom-made catheter system into 28 in situ FPAs of 14 human cadavers. Contrast-enhanced, thin-section computed tomography images were acquired with each limb in the standing (180 degrees), walking (110 degrees), sitting (90 degrees), and gardening (60 degrees) postures. Image segmentation and analysis allowed relative comparison of spatial locations of each intra-arterial marker to determine axial compression and bending using the arterial centerlines. RESULTS: Axial compression in the popliteal artery (PA) was greater than in the proximal superficial femoral artery (SFA) or the adductor hiatus (AH) segments in all postures (P = .02). Average compression in the SFA, AH, and PA ranged from 9% to 15%, 11% to 19%, and 13% to 25%, respectively. The FPA experienced significantly more acute bending in the AH and PA segments compared with the proximal SFA (P < .05) in all postures. In the walking, sitting, and gardening postures, average sphere radii in the SFA, AH, and PA ranged from 21 to 27 mm, 10 to 18 mm, and 8 to 19 mm, whereas bending angles ranged from 150 to 157 degrees, 136 to 147 degrees, and 137 to 148 degrees, respectively. CONCLUSIONS: The FPA experiences significant axial compression and bending during limb flexion that occur at even modest limb angles. Moreover, different segments of the FPA appear to undergo significantly different degrees of deformation. Understanding the effects of limb flexion on axial compression and bending might assist with reconstructive device selection for patients requiring peripheral arterial disease intervention and may also help guide the development of devices with improved characteristics that can better adapt to the dynamic environment of the lower extremity vasculature.

Limb flexion-induced twist and associated intramural stresses in the human femoropopliteal artery.

High failure rates of femoropopliteal artery (FPA) interventions are often attributed to severe mechanical deformations that occur with limb movement. Torsion of the FPA likely plays a significant role, but is poorly characterized and the associated intramural stresses are currently unknown. FPA torsion in the walking, sitting and gardening postures was characterized in n = 28 in situ FPAs using intra-arterial markers. Principal mechanical stresses and strains were quantified in the superficial femoral artery (SFA), adductor hiatus segment (AH) and the popliteal artery (PA) using analytical modelling. The FPA experienced significant torsion during limb flexion that was most severe in the gardening posture. The associated mechanical stresses were non-uniformly distributed along the length of the artery, increasing distally and achieving maximum values in the PA. Maximum twist in the SFA ranged 10-13° cm-1, at the AH 8-16° cm-1, and in the PA 14-26° cm-1 in the walking, sitting and gardening postures. Maximum principal stresses were 30-35 kPa in the SFA, 27-37 kPa at the AH and 39-43 kPa in the PA. Understanding torsional deformations and intramural stresses in the FPA can assist with device selection for peripheral arterial disease interventions and may help guide the development of devices with improved characteristics.

The choice of a constitutive formulation for modeling limb flexion-induced deformations and stresses in the human femoropopliteal arteries of different ages.

Open and endovascular treatments for peripheral arterial disease are notorious for high failure rates. Severe mechanical deformations experienced by the femoropopliteal artery (FPA) during limb flexion and interactions between the artery and repair materials play important roles and may contribute to poor clinical outcomes. Computational modeling can help optimize FPA repair, but these simulations heavily depend on the choice of constitutive model describing the arterial behavior. In this study finite element model of the FPA in the standing (straight) and gardening (acutely bent) postures was built using computed tomography data, longitudinal pre-stretch and biaxially determined mechanical properties. Springs and dashpots were used to represent surrounding tissue forces associated with limb flexion-induced deformations. These forces were then used with age-specific longitudinal pre-stretch and mechanical properties to obtain deformed FPA configurations for seven age groups. Four commonly used invariant-based constitutive models were compared to determine the accuracy of capturing deformations and stresses in each age group. The four-fiber FPA model most accurately portrayed arterial behavior in all ages, but in subjects younger than 40 years, the performance of all constitutive formulations was similar. In older subjects, Demiray (Delfino) and classic two-fiber Holzapfel-Gasser-Ogden formulations were better than the Neo-Hookean model for predicting deformations due to limb flexion, but both significantly overestimated principal stresses compared to the FPA or Neo-Hookean models.

An Anatomic Investigation of the Ober Test.

BACKGROUND: Recent studies have questioned the importance of the iliotibial band (ITB) in lateral knee pain. The Ober test or modified Ober test is the most commonly recommended physical examination tool for assessment of ITB tightness. No studies support the validity of either Ober test for measuring ITB tightness. PURPOSE/HYPOTHESIS: The purpose of this study was to assess the effects of progressive transection of the ITB, gluteus medius and minimus (med/min) muscles, and hip joint capsule of lightly embalmed cadavers on Ober test results and to compare them with assessment of all structures intact. In addition, thigh position change between gluteus med/min transection and hip capsule transection was also assessed for both versions of the Ober test. It was hypothesized that transection of the ITB would significantly increase thigh adduction range of motion as measured by an inclinometer when performing either Ober test and that subsequent structure transections (gluteus med/min muscles followed by the hip joint capsule) would cause additional increases in thigh adduction. STUDY DESIGN: Controlled laboratory study. METHODS: The lower limbs of lightly embalmed cadavers were assessed for midthigh ITB transection versus intact by use of the Ober (n = 28) and modified Ober (n = 34) tests; 18 lower limbs were assessed for all conditions (intact band, followed by sequential transections of the ITB midthigh, gluteus med/min muscles, hip joint capsule) by use of both Ober tests. Paired t tests were used to compare changes in Ober test results between conditions. RESULTS: No significant changes in thigh position (adduction) occurred in either version of the Ober test after ITB transection. Significant differences were noted for intact band versus gluteus med/min transection and intact band versus hip joint capsule transection (P < .0001) for all findings for both tests. Mean inclinometer measurements for the modified Ober were 4.28° (n = 34 for intact vs ITB transection comparisons), 3.33° (n = 18 for subsequent intact vs gluteus muscle and hip capsule transection comparisons), 5.00° (n = 34 for midthigh ITB transection), 11.20° (gluteus med/min transection), and 13.20° (hip capsule transection). For the Ober test, measures were -2.90° (n = 28 for intact vs ITB transection comparisons), -2.20° (n = 18 for subsequent intact vs gluteus muscle and hip capsule transection comparisons), -2.20° (n = 34 for midthigh ITB transection), 6.50° (gluteus med/min transection), and 9.53° (hip capsule transection). Statistically significant differences were also noted between test findings comparing gluteus med/min transection to hip capsule transection (Ober, P < .0001; modified Ober, P = .0036). CONCLUSION: The study findings refute the hypothesis that the ITB plays a role in limiting hip adduction during either version of the Ober test and question the validity of these tests for determining ITB tightness. The findings underscore the influence of the gluteus medius and minimus muscles as well as the hip joint capsule on Ober test findings. CLINICAL RELEVANCE: The results of this study suggest that the Ober test assesses tightness of structures proximal to the hip joint, such as the gluteus medius and minimus muscles and the hip joint capsule, rather than the ITB.

Assessment of a human cadaver model for training emergency medicine residents in the ultrasound diagnosis of pneumothorax.

OBJECTIVES: To assess a human cadaver model for training emergency medicine residents in the ultrasound diagnosis of pneumothorax. METHODS: Single-blinded observational study using a human cadaveric model at an academic medical center. Three lightly embalmed cadavers were used to create three "normal lungs" and three lungs modeling a "pneumothorax." The residents were blinded to the side and number of pneumothoraces, as well as to each other's findings. Each resident performed an ultrasound examination on all six lung models during ventilation of cadavers. They were evaluated on their ability to identify the presence or absence of the sliding-lung sign and seashore sign. RESULTS: A total of 84 ultrasound examinations (42-"normal lung," 42-"pneumothorax") were performed. A sliding-lung sign was accurately identified in 39 scans, and the seashore sign was accurately identified in 34 scans. The sensitivity and specificity for the sliding-lung sign were 93% (95% CI, 85-100%) and 90% (95% CI, 81-99%), respectively. The sensitivity and specificity for the seashore sign were 80% (95% CI, 68-92%) and 83% (95% CI, 72-94%), respectively. CONCLUSIONS: Lightly embalmed human cadavers may provide an excellent model for mimicking the sonographic appearance of pneumothorax.

Three-dimensional bending, torsion and axial compression of the femoropopliteal artery during limb flexion.

High failure rates of femoropopliteal artery reconstruction are commonly attributed to complex 3D arterial deformations that occur with limb movement. The purpose of this study was to develop a method for accurate assessment of these deformations. Custom-made stainless-steel markers were deployed into 5 in situ cadaveric femoropopliteal arteries using fluoroscopy. Thin-section CT images were acquired with each limb in the straight and acutely bent states. Image segmentation and 3D reconstruction allowed comparison of the relative locations of each intra-arterial marker position for determination of the artery's bending, torsion and axial compression. After imaging, each artery was excised for histological analysis using Verhoeff-Van Gieson staining. Femoropopliteal arteries deformed non-uniformly with highly localized deformations in the proximal superficial femoral artery, and between the adductor hiatus and distal popliteal artery. The largest bending (11±3-6±1 mm radius of curvature), twisting (28±9-77±27°/cm) and axial compression (19±10-30±8%) were registered at the adductor hiatus and the below knee popliteal artery. These deformations were 3.7, 19 and 2.5 fold more severe than values currently reported in the literature. Histology demonstrated a distinct sub-adventitial layer of longitudinally oriented elastin fibers with intimal thickening in the segments with the largest deformations. This endovascular intra-arterial marker technique can quantify the non-uniform 3D deformations of the femoropopliteal artery during knee flexion without disturbing surrounding structures. We demonstrate that 3D arterial bending, torsion and compression in the flexed lower limb are highly localized and are substantially more severe than previously reported.

Biaxial mechanical properties of the human thoracic and abdominal aorta, common carotid, subclavian, renal and common iliac arteries.

The biomechanics of large- and medium-sized arteries influence the pathophysiology of arterial disease and the response to therapeutic interventions. However, a comprehensive comparative analysis of human arterial biaxial mechanical properties has not yet been reported. Planar biaxial extension was used to establish the passive mechanical properties of human thoracic (TA, [Formula: see text]) and abdominal (AA, [Formula: see text]) aorta, common carotid (CCA, [Formula: see text]), subclavian (SA, [Formula: see text]), renal (RA, [Formula: see text]) and common iliac (CIA, [Formula: see text]) arteries from 11 deceased subjects ([Formula: see text] years old). Histological evaluation determined the structure of each specimen. Experimental data were used to determine constitutive parameters for a structurally motivated nonlinear anisotropic constitutive model. All arteries demonstrated appreciable anisotropy and large nonlinear deformations. Most CCA, SA, TA, AA and CIA specimens were stiffer longitudinally, while most RAs were stiffer circumferentially. A switch in anisotropy was occasionally demonstrated for all arteries. The CCA was the most compliant, least anisotropic and least frequently diseased of all arteries, while the CIA and AA were the stiffest and the most diseased. The severity of atherosclerosis correlated with age, but was not affected by laterality. Elastin fibers in the aorta, SA and CCA were uniformly and mostly circumferentially distributed throughout the media, while in the RA and CIA, elastin was primarily axially aligned and concentrated in the external elastic lamina. Constitutive modeling provided good fits to the experimental data for most arteries. Biomechanical and architectural features of major arteries differ depending on location and functional environment. A better understanding of localized arterial mechanical properties may support the development of site-specific treatment modalities for arterial disease.

Passive biaxial mechanical properties and in vivo axial pre-stretch of the diseased human femoropopliteal and tibial arteries.

Surgical and interventional therapies for atherosclerotic lesions of the infrainguinal arteries are notorious for high rates of failure. Frequently, this leads to expensive reinterventions, return of disabling symptoms or limb loss. Interaction between the artery and repair material likely plays an important role in reconstruction failure, but data describing the mechanical properties and functional characteristics of human femoropopliteal and tibial arteries are currently not available. Diseased superficial femoral (SFA, n = 10), popliteal (PA, n = 8) and tibial arteries (TA, n = 3) from 10 patients with critical limb ischemia were tested to determine passive mechanical properties using planar biaxial extension. All specimens exhibited large nonlinear deformations and anisotropy. Under equibiaxial loading, all arteries were stiffer in the circumferential direction than in the longitudinal direction. Anisotropy and longitudinal compliance decreased distally, but circumferential compliance increased, possibly to maintain a homeostatic multiaxial stress state. Constitutive parameters for a four-fiber family invariant-based model were determined for all tissues to calculate in vivo axial pre-stretch that allows the artery to function in the most energy efficient manner while also preventing buckling during extremity flexion. Calculated axial pre-stretch was found to decrease with age, disease severity and more distal arterial location. Histological analysis of the femoropopliteal artery demonstrated a distinct sub-adventitial layer of longitudinal elastin fibers that appeared thicker in healthier arteries. The femoropopliteal artery characteristics and properties determined in this study may assist in devising better diagnostic and treatment modalities for patients with peripheral arterial disease.

Enhancement of anatomical learning and developing clinical competence of first-year medical and allied health profession students.

Hands-on educational experiences can stimulate student interest, increase knowledge retention, and enhance development of clinical skills. The Lachman test, used to assess the integrity of the anterior cruciate ligament (ACL), is commonly performed by health care professionals and is relatively easy to teach to first-year health profession students. This study integrated teaching the Lachman test into a first-year anatomy laboratory and examined if students receiving the training would be more confident, competent, and if the training would enhance anatomical learning. First-year medical, physician assistant and physical therapy students were randomly assigned into either the intervention (Group A) or control group (Group B). Both groups received the course lecture on knee anatomy and training on how to perform the Lachman test during a surface anatomy class. Group A received an additional 15 minutes hands-on training for the Lachman test utilizing a lightly embalmed cadaver as a simulated patient. One week later, both groups performed the Lachman test on a lightly embalmed cadaver and later completed a post-test and survey. Students with hands-on training performed significantly better than students with lecture-only training in completing the checklist, a post-test, and correctly diagnosing an ACL tear. Students in Group A also reported being more confident after hands-on training compared to students receiving lecture-only training. Both groups reported that incorporating clinical skill activities facilitated learning and created excitement for learning. Hands-on training using lightly embalmed cadavers as patient simulators increased confidence and competence in performing the Lachman test and aided in learning anatomy.

A preliminary review of a pilot curriculum to teach open surgical skills during general surgery residency with initial feedback.

INTRODUCTION: The aim of this study is to provide a preliminary review of a pilot curriculum to teach open surgical skills during general surgery residency and obtain initial feedback. DATA SOURCE: The general surgery residency program introduced an open surgical skills training curriculum in 2009. The skills sessions are undertaken under the guidance of the faculty. An annual survey was distributed to the residents and faculty to obtain their feedback. CONCLUSIONS: A total of 50 sessions were conducted over the last 2 years. Ninety-five percent of the residents perceived this educational activity to be above average to exceptional with nearly 70% rating it as exceptional. Sixty-three percent of the faculty perceived it as above average to exceptional, with nearly 40% rating it as exceptional. The open surgical skills training curriculum was rated as the most educational activity in the program by residents and faculty alike.

Comparison of Airtraq optical laryngoscope and Storz video laryngoscope in a cadaver model.

BACKGROUND: Airway management in the emergency department is a critical intervention that requires both standard techniques and rescue techniques to ensure a high rate of success. Recently, video laryngoscope (VL) systems have become increasingly common in many large urban EDs, but these systems may exceed the budgets of smaller rural EDs and EMS services and the Airtraq optical laryngoscope (OL) may provide an effective, low-cost alternative. We hypothesized that laryngeal view and time to endothracheal tube placement for OL and VL intubations would not be significantly different. METHODS: This was a prospective, crossover trial. SETTING: University-based emergency medicine residency program procedure laboratory utilizing lightly embalmed cadavers. SUBJECTS: PGY1-3 emergency medicine residents. The study subjects performed timed endotracheal intubations alternately using the OL and VL. The subjects then rated the Cormack-Lehane laryngeal view for each device. STATISTICAL ANALYSIS: Mean time to intubation and the mean laryngeal view score were calculated with 95% confidence intervals and statistical significance was determined by Student's t test. RESULTS: Fourteen subjects completed the study. The average laryngeal view achieved with the OL vs. the VL was not significantly different, with Cormack-Lehane grade of 1.14 vs. 1.07, respectively. Time to endotracheal intubation, however, was significantly different (P<0.001) with the average time to intubation for the OL 25.49 seconds (95% CI: 17.95-33.03) and the VL 13.41 seconds (10.27-16.55). CONCLUSION: The Airtraq OL and the Storz VL yielded similar laryngeal views in the lightly embalmed cadaver model. Time to endotracheal tube placement, however, was less for the VL.

Assessment of a new model for femoral ultrasound-guided central venous access procedural training: a pilot study.

OBJECTIVES: Repetitive practice with feedback in residency training is essential in the development of procedural competency. Lightly embalmed cadaver laboratories provide excellent simulation models for a variety of procedures, but to the best of our knowledge, none describe a central venous access model that includes the key psychomotor feedback elements for the procedure, namely intravascular contents that allow for determination of correct needle position by either ultrasonographic imaging and/or aspiration or vascular contents. METHODS: A cadaver was lightly embalmed using a technique that preserves tissue texture and elasticity. We then performed popliteal fossa dissections exposing the popliteal artery and vein. Vessels were ligated distally, and 14-gauge catheters were introduced into the lumen of each artery and vein. The popliteal artery and vein were then infused with 200 mL of icterine/gel and 200 mL of methylene blue/gel, respectively. Physician evaluators then performed ultrasound (US)-guided femoral central venous line placements and rated the key psychomotor elements on a five-point Likert scale. RESULTS: The physician evaluators reported a median of 10.5 years of clinical emergency medicine (EM) experience with an interquartile range (IQR) of 16 and a median of 10 central lines placed annually (IQR = 10). Physician evaluators rated the key psychomotor elements of the simulated procedure as follows: ultrasonographic image of vascular elements, 4 (IQR = 0); needle penetration of skin, 4.5 (IQR = 1); needle penetration of vein, 5 (IQR = 1); US image of needle penetrating vein, 4 (IQR = 2); aspiration of vein contents, 3 (IQR = 2); passage of dilator into vein, 4 (IQR = 2); insertion of central venous catheter, 5 (IQR = 1); US image of catheter insertion into vein, 5 (IQR = 1); and overall psychomotor feedback of the simulated procedure compared to the evaluators' actual patient experience, 4 (IQR = 1). CONCLUSIONS: For the key psychomotor elements of central venous access, the lightly embalmed cadaver with intravascular water-soluble gel infusion provided a procedural model that closely simulated clinicians' experience with patients.