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Vaginal pessaries have been used for millennia to alleviate symptoms of pelvic organ prolapse (POP). Despite their long-standing use, the success rate of pessary treatment is approximately 60%, and the underlying mechanisms of support are not well understood. This study aims to investigate three previously proposed hypotheses regarding the support mechanisms of pessaries, utilizing supine and upright magnetic resonance imaging (MRI): (1) support by bony structures, (2) support by levator ani muscles (LAM), and (3) the uterus keeping the pessary in place by acting as a lever. Thirty POP patients, with a successful pessary fit for more than 3 months, underwent MRI scans in both upright and supine position. The position of the pelvic bony structures, LAM, uterus, and pessary were analysed by placing corresponding points on these structures and comparing the differences between supine and upright. Also, the angle of the pessary with the horizontal plane of the pelvic inclination corrections system was analysed. Principal component analysis was applied to evaluate how the positions of the LAM and the pessary changed between the two positions. The lowest point of the pessary descends below the lowest point of the bony structures in upright position, disproving the first hypothesis. The pessary significantly descends towards the LAM from supine to upright, but does not drop below it, strengthening the second hypothesis. The pessary angle is below 90° in upright position, the uterus is positioned in the pessary centre and remains constant from supine to upright, strengthening the third hypothesis. [ABSTRACT FROM AUTHOR]

The goal of this study was to compare the advantages of conventional laparoscopic surgery (CLS) and the split-leg supine position single-port plus one laparoscopic surgery (SSP SILS + 1) in esophageal surgery. This study enrolled 73 patients who previously underwent radical esophagectomy for esophageal cancer from August 2021 to February 2023. Among them, 36 patients underwent SSP SILS + 1, whereas the remaining 37 patients underwentCLS. Surgical time, bleeding volume, number of dissected lymph nodes, incision length, and postoperative abdominal pain score between the two groups of patients were compared using either the Student's t-test or chi-square test. Time of abdominal incision (1.4 ± 0.2 min vs. 5.2 ± 0.7 min, p < 0.001) was shorter in patients in the SSP SILS + 1 group compared with those in the CLS group. However, the average incision length was shorter in the SSP SILS + 1 group compared with that in the CLS group (35.4 ± 4.0 cm vs. 4.6 ± 4.1 cm, p < 0.001). Notably, the pain score on postoperative day (POD) 1 was lower in the SSP SILS + 1 group compared with that in the CLS group (5.7 ± 0.7 vs.6.3 ± 0.7, p = 0.001). The SCAR score was also lower in the SSP SILS + 1 group compared with that in the CLS group (3.5 ± 0.9 vs. 8.3 ± 1.4, p = 0.019). There was no significant difference in the number of dissected abdominal lymph nodes and positive lymph nodes (p > 0.01) between the two groups. The SSP SILS + 1 intervention offers multiple benefits over conventional surgical procedures, encompassing shorter incision length and pain scores on POD 1. In accelerated rehabilitation surgery for esophageal cancer, this surgical procedure demonstrated high safety, feasibility. [ABSTRACT FROM AUTHOR]

Although heart rate variability (HRV) is a valid method to evaluate the behavior of the autonomic nervous system in individuals with temporomandibular disorder (TMD), the measurement can easily be biased by factors involving the analysis methodology, such as the removal of artifacts. Therefore, the objective of this investigation is to evaluate the impact of using different levels of threshold-based artifact correction to process HRV data in individuals with TMD. This cross-sectional observational study. Adults aged 18 to 55 years old with a diagnosis of myogenic TMD, score ≥ 50 on the Fonseca Anamnestic Index (FAI) and pain ≥ 3 on the Numerical Pain Scale (NPS) participated. The HRV was registered in the supine position (short-term) using a Polar S810i. Kubios software was used for HRV analysis using all filters. One-way ANOVA with Tukey-Kramer post-hoc was used to test the differences in HRV using the different Kubios Software artifact correction filters. The effect size was calculated based on the Cohen d. The very strong filter was statistically different (p < 0.05) compared to the no filter in all overview and time domain variables. In the frequency domain, the variables VLF, LF, HF and Total Power showed statistical differences (p < 0.05) when using the very strong filter. The same occurred with the variables SD1, SD2 and DFA α2 of the non-linear analysis (p < 0.05). The most restrictive filter of the Kubios software (very strong) significantly impacts the quantification of HRV parameters in individuals with TMD. [ABSTRACT FROM AUTHOR]

The effect of gravity on the lungs has been evaluated using computed tomography (CT) in the supine and prone positions but not the standing position. However, as humans spend most of the daytime in the standing position, we aimed to compare lung attenuation gradients between the supine and standing positions, and to assess the correlations between the lung attenuation gradients and participant characteristics, including pulmonary function test results. Overall, 100 healthy participants underwent conventional/supine and upright CT, and lung attenuation gradients were measured. Lung attenuation gradients in anteroposterior direction were greater in the supine position than in standing position (all p values < 0.0001) in both upper lobes at the level of the aortic arch (right: standing/supine, -0.02 ± 0.19/0.53 ± 0.21; left: standing/supine, -0.06 ± 0.20/0.51 ± 0.21); in the right middle (standing/supine, -0.26 ± 0.41/0.53 ± 0.39), left upper (standing/supine, -0.35 ± 0.50/0.66 ± 0.54), and lower lobes at the level of the inferior pulmonary vein (right: standing/supine, -0.22 ± 0.30/0.65 ± 0.41; left: standing/supine, -0.16 ± 0.25/0.73 ± 0.54); and in both lower lobes just above the diaphragm (right: standing/supine, -0.13 ± 0.22/0.52 ± 0.32; left: standing/supine, -0.30 ± 0.57/0.55 ± 0.37). Craniocaudal gradients were greater in the standing position (right: standing/supine, 0.41 ± 0.30/0.00 ± 0.16; left: standing/supine, 0.35 ± 0.30/-0.02 ± 0.16, all p values < 0.0001). No moderate to very high correlations were observed between age, sex, height, weight, body index mass, or pulmonary function test results and each lung attenuation gradient. Lung attenuation gradients in anteroposterior direction, which was observed in the supine position, disappeared in the standing position. However, the craniocaudal lung attenuation gradient, which was not present in the supine position, appeared in the standing position. [ABSTRACT FROM AUTHOR]

The vector forces at the human-mattress interface are not only crucial for understanding the distribution of vertical and shear forces exerted on the human body during sleep but also serves as a significant input for biomechanical models of sleeping positions, whose accuracy determines the credibility of predicting musculoskeletal system loads. In this study, we introduce a novel method for calculating the interface vector forces. By recording indentations after supine and lateral positions using a vacuum mattress and 3D scanner, we utilize image registration techniques to align body pressure distribution with the mattress deformation scanning images, thereby calculating the vector force values for each unit area (36.25 mm × 36.25 mm). This method was validated through five participants attendance from two perspectives, revealing that (1) the mean summation of the vertical force components is 98.67% ± 7.21% body weight, exhibiting good consistency, and mean ratio of horizontal component force to body weight is 2.18% ± 1.77%. (2) the predicted muscle activity using the vector forces as input to the sleep position model aligns with the measured muscle activity (%MVC), with correlation coefficient over 0.7. The proposed method contributes to the vector force distribution understanding and the analysis of musculoskeletal loads during sleep, providing valuable insights for mattress design and evaluation. [ABSTRACT FROM AUTHOR]

Evaluating fluid responsiveness with dynamic parameters is recommended for fluid management. However, in hemodynamically stable patients who are breathing spontaneously, accurately measuring stroke volume variation via echocardiography and passive leg raising is challenging due to subtle SV changes. This study aimed to identify normal SV changes in healthy volunteers and evaluate the precision of hemodynamic parameters in screening mild hypovolemia in patients. This prospective, repeated-measures, cross-sectional study screened 269 subjects via echocardiography. Initially, 45 healthy volunteers underwent a fluid challenge test, the outcomes of which served as criteria to screen 215 ICU patients. Among these patients, 53 underwent additional fluid challenge testing. Hemodynamic parameters, including medians of maximum velocity time integrals (VTImaxs), peak velocity of VTImax (PV), internal jugular vein diameters (IJVD), and area (IJVA) were repeatedly measured first at a 60° upper body elevation (UBE), second in a supine position, third at UBE, fourth in a supine position, and lastly in a supine position after fluid loading. The hemodynamic responses to the position changes were compared between 83 fluid non-responders and 15 fluid responders. Fluid responsiveness was defined as fluid-induced medians' change of VTImaxs (fluid-induced median VTImax change) ≥ 10%. None of the healthy volunteers showed the mean value of repeatedly measured medians of VTImaxs ≥ 7%, following either UBE position (UBE-induced median VTImax change) or fluid loading (fluid-induced median VTImax change). UBE-induced median VTImax and PV changes were significantly correlated with fluid responsiveness (p < 0.001, AUC 0.959; p < 0.001, AUC 0.804). The significant correlations were demonstrated via multivariable analysis using binary logistic regression (p = 0.001, OR 90.1) and the correlation coefficient (R2 = 0.793) using linear regression analysis. UBE-induced median VTImax changes (≥ 11.8% and 7.98%) predicted fluid-induced median VTImax changes ≥ 10% and 7% (AUC 0.959 and 0.939). The collapsibility and variation of IJVD and IJVA showed no significant correlation. An increase in the mean value of medians of repeatedly measured VTImaxs transitioning from an UBE to a supine position, effectively screened mild hypovolemia and demonstrated a significant correlation with fluid responsiveness in spontaneously breathing patients maintaining hemodynamic stability. [ABSTRACT FROM AUTHOR]

In breast cancer radiation therapy, minimizing radiation-related risks and toxicity is vital for improving life expectancy. Tailoring radiotherapy techniques and treatment positions can reduce radiation doses to normal organs and mitigate treatment-related toxicity. This study entailed a dosimetric comparison of six different external beam whole-breast irradiation techniques in both supine and prone positions. We selected fourteen breast cancer patients, generating six treatment plans in both positions per patient. We assessed target coverage and organs at risk (OAR) doses to evaluate the impact of treatment techniques and positions. Excess absolute risk was calculated to estimate potential secondary cancer risk in the contralateral breast, ipsilateral lung, and contralateral lung. Additionally, we analyzed the distance between the target volume and OARs (heart and ipsilateral lung) while considering the treatment position. The results indicate that prone positioning lowers lung exposure in X-ray radiotherapy. However, particle beam therapies (PBTs) significantly reduce the dose to the heart and ipsilateral lung regardless of the patient's position. Notably, negligible differences were observed between arc-delivery and static-delivery PBTs in terms of target conformity and OAR sparing. This study provides critical dosimetric evidence to facilitate informed decision-making regarding treatment techniques and positions. [ABSTRACT FROM AUTHOR]

Augmented reality (AR) has been used for navigation during total hip arthroplasty (THA). AR computed tomography (CT)-based navigation systems and AR-based portable navigation systems that use smartphones can also be used. This study compared the accuracy of cup insertion during THA using AR-CT-based and portable AR-based navigation systems. Patients with symptomatic hip disease who underwent primary THA in the supine position using both AR CT-based and portable AR-based navigation systems simultaneously between October 2021 and July 2023 were included. The primary outcome of this study was the absolute difference between cup angles in the intraoperative navigation record and those measured on postoperative CT. The secondary outcome was to determine the factors affecting the absolute value of the navigation error in radiographic inclination (RI) and radiographic anteversion (RA) of the cup, including sex, age, body mass index, left or right side, approach, and preoperative pelvic tilt. This study included 94 consecutive patients. There were 11 men and 83 women, with a mean age of 68 years. The mean absolute errors of RI were 2.7° ± 2.0° in the AR CT-based and 3.3° ± 2.4° in the portable AR-based navigation system. The mean absolute errors of RA were 2.5° ± 2.1° in the AR CT-based navigation system and 2.3° ± 2.2° in the portable AR-based navigation system. No significant differences were observed in RI or RA of the cup between the two navigation systems (RI: p = 0.706; RA: p = 0.329). No significant factors affected the absolute value of the navigation errors in RI and RA. In conclusion, there were no differences in the accuracy of cup insertion between the AR CT-based and portable AR-based navigation systems. [ABSTRACT FROM AUTHOR]

To compare masticatory muscle thickness in patients with temporomandibular disorders (TMDs) during rest and clenching, and by body position, using ultrasonography. This prospective study included 96 patients with TMD (67 females, 29 males; mean age: 40.41 ± 17.88 years): group 1, comprising 66 patients with TMD without bruxism (TMD_nonbruxer), and group 2, comprising 30 patients with concurrent TMD and bruxism (TMD_bruxer). In patients with TMD, bruxism was correlated with the presence of tinnitus, muscle stiffness, sleep problems, psychological stress, and restricted mouth opening. The masseter muscle significantly thickened during clenching (11.16 ± 3.03 mm vs 14.04 ± 3.47 mm, p < 0.001), whereas the temporalis muscle showed no significant increase in thickness from resting to clenching in an upright position (7.91 ± 1.98 vs 8.39 ± 2.08, p = 0.103). Similarly, during clenching in the supine position, the masseter muscle was significantly thicker compared with rest (11.24 ± 2.42 vs 13.49 ± 3.09, p < 0.001), but no significant difference was observed in temporal muscle thickness (8.21 ± 2.16 vs 8.43 ± 1.94, p = 0.464). In comparison between two groups, the average thickness of the masseter muscle was greater among TMD_bruxers than among TMD_nonbruxers in both the upright and supine positions (all p < 0.05). In the generalized lineal model, female sex (B = − 1.018, 95% confidence interval [CI] − 1.855 to − 0.181, p = 0.017) and bruxism (B = 0.868, 95% CI 0.567 to 1.169, p = 0.048) significantly predicted changes in masseter muscle thickness. Female sex (B = − 0.201, 95% CI − 0.299 to − 0.103, p = 0.011), increased age (B = − 0.003, 95% CI − 0.005 to 0.000, p = 0.038), and muscle stiffness (B = − 1.373, 95% CI − 2.369 to − 0.376, p = 0.007) were linked to decreased temporal muscle thickness. Comparing TMD nonbruxer and bruxer muscle thicknesses in upright and supine positions revealed significant increased thickness in the masseter muscle during clenching but not in the temporalis muscle. Masseter muscle thickness varied significantly by sex, body position, and resting/clenching, notably influenced by bruxism. These findings emphasize the relevance of these factors in clinical examinations of patients with TMD. [ABSTRACT FROM AUTHOR]

The capacitive measurement of the head's dielectric properties has been recently proposed as a noninvasive method for deriving surrogates of craniospinal compliance (CC), a parameter used in the evaluation of space-occupying neurological disorders. With the higher prevalence of such disorders in the older compared to the younger population, data on the head's dielectric properties of older healthy individuals would be of particularly high value before assessing pathologic changes. However, so far only measurements on young volunteers (< 30 years) were reported. In the present study, we have investigated the capacitively obtained electric signal known as W in older healthy individuals. Thirteen healthy subjects aged > 60 years were included in the study. W was acquired in the resting state (supine horizontal position), and during head-up and head-down tilting. AMP, the peak-to-valley amplitude of W related to cardiac action, was extracted from W. AMP was higher in this older cohort compared to the previously investigated younger one (0°: 5965 ± 1677 arbitrary units (au)). During head-up tilting, AMP decreased (+ 60°: 4446 ± 1620 au, P < 0.001), whereas it increased during head-down tilting (− 30°: 7600 ± 2123 au, P < 0.001), as also observed in the younger cohort. Our observation that AMP, a metric potentially reflective of CC, is higher in the older compared to the younger cohort aligns with the expected decrease of CC with age. Furthermore, the robustness of AMP is reinforced by the consistent relative changes observed during tilt testing in both cohorts. [ABSTRACT FROM AUTHOR]

The present study sought to expand upon prior investigations of the relationship between post-exercise heart rate recovery (HRR) and cardiovagal resting-reactivity modulation. HRR from 1st to 5th min after maximal exercise test was correlated with a cardiovagal index of heart rate variability (SD1) at resting (supine and orthostatic positions) and its reactivity after the orthostatic stress test in 34 healthy women. Statistical analysis employed non-parametric tests with a p-value set at 5%. HRR, ∆%HRR, and coefficient of HRR (CHRR) at the 3rd and 5th min correlated with SD1 and SD1n (normalized units) in the supine position (rs = 0.36 to 0.47; p = < 0.01). From the 1st to 5th min, HRR, ∆%HRR, and CHRR correlated with SD1 and SD1n in the orthostatic position (rs = 0.29 to 0.47; p = ≤ 0.01 to 0.05), except for HRR at 5th min with SD1n (p = 0.06). Following the orthostatic stress test, HRR at 3rd and HRR, %∆HRR at 5th min correlated with ∆absSD1 (rs = 0.28 to 0.35; p = 0.02 to 0.05). All HRR measurements at 1st min correlated with ∆absSD1n (rs = 0.32 to 0.38; p = 0.01 to 0.03), and the CHRR at 1st min correlated with ∆%SD1(rs = 0.37; p = 0.01). After the sample was divided into high and low cardiovagal modulation subgroups, the subgroup with high modulation at rest (supine and orthostatic) and higher cardiovagal reactivity (reduction) showed faster HRR (p = ≤ 0.01 to 0.05; ES:0.37 to 0.50). HRR throughout the 1st to 5th min positively correlates with cardiovagal modulation in the orthostatic position, and the 3rd and 5th min positively correlate with cardiovagal modulation in both postures at rest. Faster HRR following the maximal exercise test is associated with high resting-reactivity cardiovagal modulation in healthy women. [ABSTRACT FROM AUTHOR]

In recent years, a variety of deep learning networks for cardiac MRI (CMR) segmentation have been developed and analyzed. However, nearly all of them are focused on cine CMR under breathold. In this work, accuracy of deep learning methods is assessed for volumetric analysis (via segmentation) of the left ventricle in real-time free-breathing CMR at rest and under exercise stress. Data from healthy volunteers (n = 15) for cine and real-time free-breathing CMR at rest and under exercise stress were analyzed retrospectively. Exercise stress was performed using an ergometer in the supine position. Segmentations of two deep learning methods, a commercially available technique (comDL) and an openly available network (nnU-Net), were compared to a reference model created via the manual correction of segmentations obtained with comDL. Segmentations of left ventricular endocardium (LV), left ventricular myocardium (MYO), and right ventricle (RV) are compared for both end-systolic and end-diastolic phases and analyzed with Dice's coefficient. The volumetric analysis includes the cardiac function parameters LV end-diastolic volume (EDV), LV end-systolic volume (ESV), and LV ejection fraction (EF), evaluated with respect to both absolute and relative differences. For cine CMR, nnU-Net and comDL achieve Dice's coefficients above 0.95 for LV and 0.9 for MYO, and RV. For real-time CMR, the accuracy of nnU-Net exceeds that of comDL overall. For real-time CMR at rest, nnU-Net achieves Dice's coefficients of 0.94 for LV, 0.89 for MYO, and 0.90 for RV and the mean absolute differences between nnU-Net and the reference are 2.9 mL for EDV, 3.5 mL for ESV, and 2.6% for EF. For real-time CMR under exercise stress, nnU-Net achieves Dice's coefficients of 0.92 for LV, 0.85 for MYO, and 0.83 for RV and the mean absolute differences between nnU-Net and reference are 11.4 mL for EDV, 2.9 mL for ESV, and 3.6% for EF. Deep learning methods designed or trained for cine CMR segmentation can perform well on real-time CMR. For real-time free-breathing CMR at rest, the performance of deep learning methods is comparable to inter-observer variability in cine CMR and is usable for fully automatic segmentation. For real-time CMR under exercise stress, the performance of nnU-Net could promise a higher degree of automation in the future. [ABSTRACT FROM AUTHOR]

The objective of this research is to examine the impact of eccentric training on hamstring flexibility and strength in young dancers during the concluding stages of their foundational dance training program. A total of 24 female, second-year dance students from Hebei Normal University were selected as participants. They were divided into three distinct groups: Nordic hamstring exercise and single-leg deadlift group (NHE&SLD), forward bending exercises and standing leg lift group (FBE&SLL), and a control group (CG). The study was designed around a 6-week training regimen. An isokinetic dynamometer was used to measure seated knee flexor–extensor strength, while electronic goniometry was employed to measure hamstring flexibility in the supine position. Paired sample t-tests were conducted within each group, and one-way analysis of covariance (ANCOVA) was utilized for comparisons between groups. In the NHE&SLD group, significant disparities were observed in both concentric (T = − 5.687, P = 0.001) and eccentric (T = − 3.626, P = 0.008) hamstring strength pre and post-intervention. The pre-intervention dominant leg concentric strength test values significantly influenced the post-intervention outcomes (F = 5.313, P = 0.001, η2 = 0.840). Similarly, the pre-intervention dominant leg eccentric strength test values impacted the post-intervention results (F = 4.689, P = 0.043, η2 = 0.190). Following the intervention, the NHE&SLD group displayed marked changes in the active straight leg raising angle on both left (T = − 4.171, P = 0.004) and right (T = − 6.328, P = 0.001) sides. The FBE&SLL group also revealed significant changes in the active straight leg raising angle on both left (T = − 4.506, P = 0.003) and right (T = − 4.633, P = 0.002) sides following the intervention. The pre-intervention left leg concentric strength test value significantly influenced the post-intervention outcomes (F = 25.067, P = 0.001, η2 = 0.556). Likewise, the pre-intervention right leg eccentric strength test value significantly influenced the post-intervention results (F = 85.338, P = 0.01, η2 = 0.810). Eccentric training can better enhance the flexibility and strength of hamstring muscles in dance students. Traditional stretching training significantly improves the flexibility of the hamstring muscles. Eccentric training has more training benefits than traditional stretching training. It is recommended for dance students to use eccentric training when increasing hamstring flexibility and strength. [ABSTRACT FROM AUTHOR]

Obesity is frequently associated with breathing disorders. To investigate if and how the highest levels of obesity impact respiratory function, 17 subjects with obesity (median age: 49 years; BMI: 39.7 kg/m2, 8 females) and 10 normal-weighted subjects (49 years; 23.9 kg/m2, 5 females) were studied. The abdominal volume occupied 41% in the obese group, being higher (p < 0.001) than the normal-weighted group (31%), indicating accumulation of abdominal fat. Restrictive lung defect was present in 17% of subjects with obesity. At rest in the supine position, subjects with obesity breathed with higher minute ventilation (11.9 L/min) and lower ribcage contribution (5.7%) than normal weighted subjects (7.5 L/min, p = 0.001 and 31.1%, p = 0.003, respectively), thus indicating thoracic restriction. Otherwise healthy obesity might not be characterized by a systematic restrictive lung pattern. Despite this, another sign of restriction could be poor thoracic expansion at rest in the supine position, resulting in increased ventilation. Class 3 obesity made respiratory rate further increased. Opto-electronic plethysmography and its thoraco-abdominal analysis of awake breathing add viable and interesting information in subjects with obesity that were complementary to pulmonary function tests. In addition, OEP is able to localize the restrictive effect of obesity. [ABSTRACT FROM AUTHOR]

Portable navigation systems have been developed for use in total hip arthroplasty (THA) in recent years. Although intraoperative registration in the lateral decubitus position or the supine position is need to create the three-dimensional coordinate system, it is not clear which position is appropriate. The purpose of this study was to assess the accuracy of cup placement in primary THA in the lateral decubitus position using an image-free handheld navigation device with registration in the lateral decubitus or the supine position, and clarify which position is appropriate. This retrospective study included 129 consecutive cementless THAs performed using an image-free handheld navigation device in the lateral decubitus position. Registration in the first 68 hips was performed in the lateral decubitus position and the last 61 hips was performed in the supine position. Postoperative cup radiographic inclination and radiographic anteversion were assessed, and the accuracy was compared between the two groups. The mean absolute errors of the postoperative measured inclination and anteversion from the target angles were 3.9° ± 2.2° and 4.8° ± 3.5° in the lateral group and 2.9° ± 2.7° and 3.2° ± 2.7° in the supine group (p < 0.05). The percentage of cups inside Lewinnek's safe zone was 94% in the lateral group and 95% in the supine group (ns). The mean absolute values of navigation error in inclination and anteversion were 3.1° ± 2.1° and 4.2° ± 2.8° in the lateral group and 2.3° ± 2.0° and 3.1° ± 2.4° in the supine group (p < 0.05 and p < 0.05). Registration in the supine position improved the accuracy of cup insertion compared with the lateral decubitus position in THA using an image-free handheld navigation device in the lateral decubitus position. [ABSTRACT FROM AUTHOR]

The correlation between the anatomical cardiac and electrocardiographic axes has been discussed for several years. Using upright computed tomography, this study aimed to reveal the relationship between the anatomical cardiac and electrocardiographic axes in both the supine and upright positions. Upright CT and standard supine CT were performed for healthy volunteers, following electrocardiography in both upright and supine position. On CT images, the coordinates of apex, the center of aortic valve (AV) and mitral valve (MV) were recorded, and the vectors and angles were calculated. Subcutaneous and visceral fat volume were semi-automatically calculated in a workstation. From a total 190 volunteers, 41 males were performed electrocardiography and included for this study. The QRS and anatomical axes (AV-apex and MV-apex axis) were significantly correlated in both supine and upright positions, while the angle of the AV-apex to Z axis was the most correlated (supine: r = − 0.54, p = 0.0002, upright: r = − 0.47, p = 0.0020). The anatomical axis moved in the dorsal and caudal directions from the supine to upright position. Multiple regression analysis revealed that the anatomical axis from the AV-apex to the Z-axis was determined according to age, body height, subcutaneous and visceral fat volumes. [ABSTRACT FROM AUTHOR]

Dry electroencephalography (EEG) electrodes provide rapid, gel-free, and easy EEG preparation, but with limited wearing comfort. We propose a novel dry electrode comprising multiple tilted pins in a flower-like arrangement. The novel Flower electrode increases wearing comfort and contact area while maintaining ease of use. In a study with 20 volunteers, we compare the performance of a novel 64-channel dry Flower electrode cap to a commercial dry Multipin electrode cap in sitting and supine positions. The wearing comfort of the Flower cap was rated as significantly improved both in sitting and supine positions. The channel reliability and average impedances of both electrode systems were comparable. Averaged VEP components showed no considerable differences in global field power amplitude and latency, as well as in signal-to-noise ratio and topography. No considerable differences were found in the power spectral density of the resting state EEGs between 1 and 40 Hz. Overall, our findings provide evidence for equivalent channel reliability and signal characteristics of the compared cap systems in the sitting and supine positions. The reliability, signal quality, and significantly improved wearing comfort of the Flower electrode allow new fields of applications for dry EEG in long-term monitoring, sensitive populations, and recording in supine position. [ABSTRACT FROM AUTHOR]

Standard supine Magnetic Resonance Imaging (MRI) does not acquire images in a position where most patients with intermittent arm radiculopathy have symptoms. The aim of this study was to test the feasibility of a new compression device and to evaluate image quality and foraminal properties during a Spurling test under MRI acquisition. Ten asymptomatic individuals were included in the study (6 men and 4 women; age range 27 to 55 years). First, the subjects were positioned in the cervical compression device in a 3 T MRI scanner, and a volume T2 weighted (T2w) sequence was acquired in a relaxed supine position (3 min). Thereafter, the position and compressive forces on the patient's neck (provocation position) were changed by maneuvering the device from the control room, with the aim to simulate a Spurling test, causing a mild foraminal compression, followed by a repeated image acquisition (3 min). A radiologist measured the blinded investigations evaluating cervical lordosis (C3–C7), foraminal area on oblique sagittal images and foraminal cross-distance in the axial plane. A total of three levels (C4–C7) were measured on the right side on each individual. Measurements were compared between the compressed and relaxed state. Reliability tests for inter- and intraclass correlation were performed. The device was feasible to use and well tolerated by all investigated individuals. Images of adequate quality was obtained in all patients. A significant increase (mean 9.4, p = 0.013) in the cervical lordosis and a decreased foraminal cross-distance (mean 32%, p < 0.001) was found, during the simulated Spurling test. The area change on oblique sagittal images did not reach a statistically significant change. The reliability tests on the quantitative measures demonstrated excellent intraobserver reliability and moderate to good interobserver reliability. Applying an individualized provocation test on the cervical spine, which simulates a Spurling test, during MRI acquisition was feasible with the novel device and provided images of satisfactory quality. MRI images acquired with and without compression showed changes in cervical lordosis and foraminal cross distance indicating the possibility of detecting changes of the foraminal properties. As a next step, the method is to be tested on symptomatic patients. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the influence of skin distortion due to surgical positioning on the clinical accuracy of the navigation system. The distance errors were measured in four fiducial markers (anterior, posterior, right, and left of the head) after the registration of the navigation system. The distance errors were compared between the surface-merge registration (SMR) method using preoperative imaging and the automatic intraoperative registration (AIR) method using intraoperative imaging. The comparison of the distance errors were performed in various surgical positions. The AIR method had the significant accuracy in the lateral markers than the SMR method (lateral position, 3.8 mm vs. 8.95 mm; p < 0.0001; prone position, 4.5 mm vs. 13.9 mm; p = 0.0001; 5.2 mm vs. 11.5 mm; p = 0.0070). The smallest distance errors were obtained close to the surgical field in the AIR method (3.25–3.85 mm) and in the forehead in the SMR method (3.3–8.1 mm). The AIR method was accurate and recommended for all the surgical positions if intraoperative imaging was available. The SMR method was only recommended for the supine position, because skin distortion was frequently observed in the lateral region. [ABSTRACT FROM AUTHOR]

Upright computed tomography (CT) provides physiologically relevant images of daily life postures (sitting and standing). The volume of the human airway in sitting or standing positions remains unclear, and no clinical study to date has compared the inspiratory and expiratory airway volumes and luminal areas among standing, sitting, and supine positions. In this prospective study, 100 asymptomatic volunteers underwent both upright (sitting and standing positions) and conventional (supine position) CT during inspiration and expiration breath-holds and the pulmonary function test (PFT) within 2 h of CT. We compared the inspiratory/expiratory airway volumes and luminal areas on CT among the three positions and evaluated the correlation between airway volumes in each position on CT and PFT measurements. The inspiratory and expiratory airway volumes were significantly higher in the sitting and standing positions than in the supine position (inspiratory, 4.6% and 2.5% increase, respectively; expiratory, 14.9% and 13.4% increase, respectively; all P < 0.001). The inspiratory and expiratory luminal areas of the trachea, bilateral main bronchi, and average third-generation airway were significantly higher in the sitting and standing positions than in the supine position (inspiratory, 4.2‒10.3% increases, all P < 0.001; expiratory, 6.4‒12.8% increases, all P < 0.0001). These results could provide important clues regarding the pathogenesis of orthopnea. Spearman's correlation coefficients between the inspiratory airway volume on CT and forced vital capacity and forced expiratory volume in 1 s on PFT were numerically higher in the standing position than in the supine position (0.673 vs. 0.659 and 0.669 vs. 0.643, respectively); however, no statistically significant differences were found. Thus, the airway volumes on upright and conventional supine CT were moderately correlated with the PFT measurements. [ABSTRACT FROM AUTHOR]

Microgravity has been shown to be a significant stressor on the cardiovascular system and the brain due to the redistribution of fluids that occurs in the absence of gravitational force, but there is scarce literature surrounding the effects of microgravity on cerebral hemodynamics and cognition. Understanding the early effects that simulated gravity has on cognitive function is essential for developing proper physical and cognitive countermeasures to assure safe and effective cognitive/decisions making while astronauts prepare for the initial launch or when they arrive in a microgravity environment. Therefore, this study aims to determine how an acute simulation of microgravity would alter cerebral oxygenation and executive functions. Sixty-five young healthy participants (22 ± 6 years, 21 females) completed a thirty (30) minute horizontal (00 tilt) followed by a 90-min − 6° head-down-tilt (HDT) protocol. Cerebral oxygenation in the prefrontal cortex was monitored throughout the testing session using near-infrared spectroscopy. Cognition was also measured using a computerized Stroop Task. Our results demonstrate that cerebral oxygenation was higher during HDT compared to the horizontal supine position (9.11 ± 1.3 vs. 7.51 ± 1.8, p = 0.02). For the cognitive results, the non-executive performance of the Stroop task remained stable during HDT (652.46 ± 19.3 vs. 632.49 ± 14.5, p = 0.09). However, reaction time during the executive task performance was improved after the HDT (1058 ± 195–950 ± 158 ms, p < 0.01). Our results suggest that an acute bout of simulated microgravity can enhance executive functioning. [ABSTRACT FROM AUTHOR]

This prospective ex vivo study investigated microdamage to single-use flexible ureteroscopes (fURS) after ureteroscopy and endoscopic combined intrarenal surgery (ECIRS). The performance of 30 WiScope devices (OTU Medical, San Jose, CA, USA) was examined immediately after use, dividing them into three equal groups: ureteroscopy and ECIRS in the prone and supine positions. The overall scope of microdamage assessment included the scope deflection, bending radius, resolution, and water flow rate. Additionally, we analyzed the association between scope status and surgical parameters. The deflection, bending radius, and resolution remained similarly above the thresholds in all groups. However, the water flow rate was below the threshold in seven scopes (70%) in the ureteroscopy group and none in the ECIRS groups (P = 0.001). Univariate and multivariable logistic regression analyses demonstrated that basket wire catheter use was associated with an increased risk for overall scope microdamage (odds ratio [OR], 22.70; P = 0.006 and OR, 22.40; P = 0.019, respectively). Stone size, total laser energy, and surgical position were not associated with a risk for scope microdamage. In conclusion, ureteroscopy was more closely associated with scope damage than ECIRS, and basket wire catheter use seemed to inflict more damage to the fURS. [ABSTRACT FROM AUTHOR]

Real-time effects of changing body position and positive end-expiratory pressure (PEEP) on regional lung overdistension and collapse in individual patients remain largely unknown and not timely monitored. The aim of this study was to individualize PEEP in supine and prone body positions seeking to reduce lung collapse and overdistension in mechanically ventilated patients with coronavirus disease (COVID-19)-induced acute respiratory distress syndrome (ARDS). We hypothesized that prone positioning with bedside titrated PEEP would provide attenuation of both overdistension and collapse. In this prospective observational study, patients with COVID-19-induced ARDS under mechanical ventilation were included. We used electrical impedance tomography (EIT) with decremental PEEP titration algorithm (PEEPEIT-titration), which provides information on regional lung overdistension and collapse, along with global respiratory system compliance, to individualize PEEP and body position. PEEPEIT-titration in supine position followed by PEEPEIT-titration in prone position were performed. Immediately before each PEEPEIT-titration, the same lung recruitment maneuver was performed: 2 min of PEEP 24 cmH2O and driving pressure of 15 cmH2O. Forty-two PEEPEIT-titration were performed in ten patients (21 pairs supine and prone positions). We have found larger % of overdistension along the PEEP titration in prone than supine position (P = 0.042). A larger % of collapse along the PEEP titration was found in supine than prone position (P = 0.037). A smaller respiratory system compliance was found in prone than supine position (P < 0.0005). In patients with COVID-19-induced ARDS, prone body position, when compared with supine body position, decreased lung collapse at low PEEP levels, but increased lung overdistension at PEEP levels greater than 10 cm H2O. Trial registration number: NCT04460859. [ABSTRACT FROM AUTHOR]

Mass vaccination against coronavirus disease 2019 (COVID-19) is ongoing in many countries worldwide. This study reports the occurrence of acute adverse events among vaccine recipients at a mass vaccination center in Japan. Between August and November 2021, approximately 130,000 individuals received two mRNA vaccine doses (mRNA-1273; Moderna) at the vaccination center. Acute adverse events at the site were observed in 1.1% of the recipients after the first dose and in 0.4% of the recipients after the second dose. The most common event was vasovagal syncope/presyncope, followed by acute allergic reactions. The occurrence rate of vasovagal syncope/presyncope was highest in the young population of those aged 16–29 years, but such age-dependency was not apparent in acute allergic reactions. Both symptoms were more prevalent in women than in men. Vasovagal syncope/presyncope occurred mainly within 20 min of the injection, whereas nearly half of the episodes of acute allergic reactions occurred after 20 min. The vaccine being injected while the recipient was in the supine position effectively reduced the occurrence of vasovagal syncope/presyncope. In summary, the suggested risk factors for vasovagal syncope/presyncope included a young age and female sex. The vaccine being injected while the recipient was in the supine position would reduce the risk of vasovagal syncope/presyncope. [ABSTRACT FROM AUTHOR]

Although most patients who undergo transforaminal lumbar interbody fusion (TLIF) show favorable surgical results, some still have unfavorable results for various reasons. This study aimed to investigate the influence of differences in lumbar lordosis (LL) between the standing and supine positions (DiLL: supine LL–standing LL) on minimum 5-year surgical outcomes after short-segment TLIF. Ninety-one patients with lumbar degenerative disease who underwent short-segment TLIF (1–2 levels) were categorized based on preoperative differences in LL as DiLL (+) and DiLL (−). Comparison and correlation analyses were performed. The incidence of adjacent segment disease (ASD) by radiology (R-ASD) and symptomatic ASD (S-ASD), bony fusion rates, and pre- and postoperative clinical scores (visual analog scale [VAS]; Japanese Orthopaedic Association [JOA] score; Oswestry disability index (ODI); and Nakai's score) were evaluated. Postoperatively, VAS for low back pain (LBP) in the sitting position, JOA scores for LBP, lower leg pain, intermittent claudication, ODI, and Nakai's score were significantly worse in the DiLL (+) group than in the DiLL (−) group. DiLL values were significantly correlated with VAS for LBP, ODI, and Nakai's score, postoperatively. Positive DiLL values were associated with poorer postoperative outcomes. DiLL is a simple and useful method for predicting mid-term outcomes after TLIF. [ABSTRACT FROM AUTHOR]

A thorough understanding of lumbar segmental motion is valuable to treat patients with degenerative lumbar disease, but kinematics associated with indicators of lumbar intervertebral instability [traction spur, Modic changes (MCs) and vacuum phenomenon (VP)] in the lumbar spine have not been well understood. The purpose of this study is to evaluate the relationships between traction spur, MCs and VP to radiographic measurements in the lumbar spine. A total of 525 lumbar discs from L1-2 to L5-S1 of 105 patients were evaluated. The sagittal translation (ST) and sagittal angulation were measured from the radiographs taken flexion–extension. The anterior disc height (ADH) was measured from the lateral radiographs, and ΔADH was measured as the difference from supine to sitting position. Logistic regression analyses were used to detect the association between the existence of traction spur, MCs and VP and related factors. Multivariate analysis showed that the traction spur was significantly related to translational motion (ST > 2 mm, OR 4.74) and the VP was significantly related to vertical motion (ΔADH > 3 mm, OR 1.94). These results suggest that the segments with traction spur and VP should be evaluated carefully because these may be a sign of lumbar intervertebral instability. [ABSTRACT FROM AUTHOR]

We evaluated the physiological benefits of performing lung recruitment maneuver (LRM) in the semi-lateral position compared in the supine position. Seventy-nine patients undergoing laparoscopic prostatectomy were randomly assigned to either the supine or semi-lateral group according to body position during the LRM. At the end of surgery, LRM (35 cmH2O for 20 s) was performed twice in the assigned posture. The primary outcome was the maximal decrease in systolic arterial pressure during LRM. Secondary outcomes were changes in PaO2/FiO2 and the regional lung volume distribution after LRM. The decrease in systolic arterial pressure during the LRM was significantly higher in the supine group than in the semi-lateral group (mean ± standard deviation, [−] 27.6 ± 14.6% vs. [−] 18.6 ± 9.9%, P = 0.001). Improvement in PaO2/FiO2 ratio after the LRM was evident in both groups but was more prominent in the semi-lateral group than in the supine group (median [interquartile range], 39.3% [20.2, 63.6] vs. 18.2% [8.4, 29.2], P = 0.001). Among the horizontal lung divisions, regional lung volume in the most dependent portion (the dorsal division) was significantly increased after the LRM only in the semi-lateral group (P = 0.024). Performing lung recruitment in a semi-lateral position protected against hemodynamic deterioration during the LRM and increased regional lung ventilation in the dependent portion of the lung, leading to an improvement in arterial oxygenation after laparoscopic procedures. Trial registration Clinical Research Information Service (https://cris.nih.go.kr/). Identifier: KCT0003756. [ABSTRACT FROM AUTHOR]

Tpeak-Tend interval (Tp-Te) is an indicator of transmural dispersion of repolarization, which is often related to ventricular arrhythmias. The relationship between Tp-Te and vasovagal syncope (VVS) has been reported in previous studies, but very little is known about Tp-Te in differentiation between psychogenic pseudosyncope (PPS) and VVS in children. We aim to discuss the predictive value of Tp-Te of supine and orthostatic electrocardiogram (ECG) in the diagnosis between PPS and VVS in children. The 31 children with PPS and 40 children with VVS from July 2014 to November 2023 were enrolled as the study group. Meanwhile, 30 healthy children who underwent a physical examination in the same hospital were selected as the control group. Tp-Te and QT interval in 12-lead supine and orthostatic ECG were measured. (1) Supine ECG: ① The Tp-Te/QT in PPS group was significantly lower than that in control group in II lead (P < 0.05). The Tp-Te/QTc in PPS group was significantly lower than that in control group in II and aVR lead (P < 0.05). There was no significant difference in Tp-Te between PPS group and control group (P > 0.05). ② The Tp-Te in VVS group was significantly higher than that in control group in aVR, aVF, and V 4 lead (P < 0.05). The Tp-Te/QT in VVS group was significantly higher than that in control group in aVF lead (P < 0.05). The Tp-Te/QTc in VVS group was significantly higher than that in control group in aVL, aVF and V 1 lead (P < 0.05). ③ The Tp-Te, Tp-Te/QT in PPS group were significantly lower than those in VVS group in some leads (P < 0.05). The Tp-Te/QTc in PPS group was significantly lower than that in VVS group in some leads. (2) Orthostatic ECG: ① The Tp-Te in PPS group was significantly higher than that in control group in V 1 , V 2 lead (P < 0.05). The Tp-Te/QT, Tp-Te/QTc in PPS group were significantly higher than those in control group in V 2 lead (P < 0.05). ② The Tp-Te and Tp-Te/QTc in V 4 lead, Tp-Te/QT in V 1 , V 4 lead in VVS group were significantly higher than those in control group (P < 0.05). ③ The Tp-Te in PPS group was significantly lower than that in VVS group in some leads (P < 0.05). The Tp-Te/QT in PPS group was significantly lower than that in VVS group in some leads (P < 0.05). The Tp-Te/QTc in PPS group was significantly lower than that in VVS group in some leads. (3) The receiver-operating characteristic (ROC) curve analysis: Tp-Te of supine ECG and orthostatic ECG in some leads had a predictive value on diagnosis between PPS and VVS (P < 0.05). Tp-Te, Tp-Te/QT, and Tp-Te/QTc of supine and orthostatic ECG in some leads have a certain predictive value in the diagnosis between PPS and VVS in children., Competing Interests: Declarations Competing interests The authors declare no competing interests. Ethics approval and consent to participate Written informed consent must had been obtained from a parent and/or legal guardian before HUTT. This research was approved by the Medical Ethics Committee of The Second Xiangya Hospital, Central South University (2014-012), and conforms to the principles stated in the Declaration of Helsinki., (© 2024. The Author(s).)

The aim of this study was to identify the applicability of an ultrasound-guided attenuation parameter (UGAP) for the noninvasive assessment of hepatic steatosis in clinical practice and to compare its correlation with B-mode ultrasound (US). From May to July 2021, 63 subjects with different body mass index (BMI) grades were included in the prospective study. All of them performed UGAP measurements, under different breathing manipulations, positions, diet statuses, and operators. After that, the UGAP values were compared with the visual grades of hepatic steatosis on B-mode US using a 4-point scale method. The intraclass correlation (ICC) of the UGAP values between the two radiologists was 0.862 (p < 0.001), and the ICCs of the UGAP values on the same day and different days by radiologist A were 0.899 (p < 0.001) and 0.910 (p < 0.001), respectively. There were no significant differences in UGAP values under different breathing manipulations (p > 0.05), positions (p > 0.05), or diet statuses (p = 0.300). The UGAP values in the fasting (supine position, segment V, 1) condition among the lean (BMI < 24 kg/m2), overweight (24 kg/m2 ≤ BMI < 28 kg/m2) and obese groups (BMI ≥ 28 kg/m2) were 0.60 ± 0.12, 0.66 ± 0.14, and 0.71 ± 0.11 dB/cm/MHz, respectively, with a significant difference (p = 0.006). The correlation coefficients (Rho) between the UGAP values and the visual grades of hepatic steatosis by the two reviewers were 0.845 (p < 0.001) and 0.850 (p < 0.001), corresponding to a strong relationship. Steatosis grades by reviewer 1 (p = 0.036) and reviewer 2 (p = 0.003) were significant factors determining the UGAP values according to the multivariate linear regression analysis. UGAP demonstrated excellent intraobserver and interobserver reproducibility in the assessment of hepatic steatosis. UGAP may be a promising tool in clinical practice to predict hepatic steatosis. [ABSTRACT FROM AUTHOR]

Placement of central venous catheters (CVC) into the internal jugular vein represents a routine clinical intervention. The periprocedural complication rate ranges from 5 to 20% and can be reduced by ultrasound guidance, training of residents and other measures. We aimed to proof that the average Seldinger needle is too long, increasing the risk of periprocedural injury, best epitomized in the stellate ganglion injury/irritation. The first part of the study was an online market analysis to investigate the standard needle length currently offered as part of the CVC placement sets. The second part of the study involved 35 hospitalized patients (14 female; median age 74.5 years). In those the distance between the skin and the internal jugular vein as well as the diameter of the internal jugular vein was measured by ultrasound in both, supine position as well as 45° semi-sitting position. In the third part of the study 80 body donors (45 female; median age 83.0 years) preserved by the ethanol/formaldehyde method were studied. In those the distance and angle between the typical landmark for insertion of the Seldinger needle for internal jugular vein catheter placement to the stellate ganglion was measured. The median [interquartile range] Seldinger needle length was 7 [4.0–10.0] cm. In the examined patients the maximum distance between the skin and the internal jugular vein was 1.87 cm. The minimum distance was 0.46 cm and the median distance averaging supine and 45° position was 1.14 [0.94–1.31] cm. Regarding the body donors the median distance from the insertion point of the internal jugular vein to the stellate ganglion was longer in men 5.5 [4.95–6.35] cm than in women 5.2 [4.7–5.9] (p = 0.031 unpaired t-test). With 7 cm average length the Seldinger needle currently sold as part of CVC sets is long enough to physically reach the stellate ganglion, not to mention more proximal structures. A shorter needle length would be sufficient to reach the internal jugular vein even in obese patients and with a small insertion angle while minimizing the possibility to cause severe injury as structures like the pleura and the stellate ganglion could not be reached by shorter needles. [ABSTRACT FROM AUTHOR]

In whole breast and regional nodal irradiation (WB + RNI), breathhold increases organ at risk (OAR) sparing. WB + RNI is usually performed in supine position, because positioning materials obstruct beam paths in prone position. Recent advancements allow prone WB + RNI (pWB + RNI) with increased sparing of OARs compared to supine WB + RNI. We evaluate positional and dosimetrical impact of repeated breathhold (RBH) and failure to breathhold (FTBH) in pWB + RNI. Twenty left-sided breast cancer patients were scanned twice in breathhold (baseline and RBH) and once free breathing (i.e. FTBH). Positional impact was evaluated using overlap index (OI) and Dice similarity coefficient (DSC). Dosimetrical impact was assessed by beam transposition from the baseline plan. Mean OI and DSC ranges were 0.01–0.98 and 0.01–0.92 for FTBH, and 0.73–1 and 0.69–1 for RBH. Dosimetric impact of RBH was negligible. FTBH significantly decreased minimal dose to CTV WBI, level II and the internal mammary nodes, with adequate mean doses. FTBH significantly increased heart, LAD, left lung and esophagus dose. OI and DSC for RBH and FTBH show reproducible large ROI positions. Small ROIs show poor overlap. FTBH maintained adequate target coverage but increased heart, LAD, ipsilateral lung and esophagus dose. RBH is a robust technique in pWB + RNI. (Clinicaltrials.gov: NCT05179161, registered 05/01/2022). [ABSTRACT FROM AUTHOR]

Composite tool use (using more than one tool simultaneously to achieve an end) has played a significant role in the development of human technology. Typically, it depends on a number of specific and often complex spatial relations and there are thus very few reported cases in non-human animals (e.g., specific nut-cracking techniques in chimpanzees and capuchin monkeys). The innovative strategies underlying the innovation and spread of tool manufacture and associative tool use (using > 1 tools) across tool using animals is an important milestone towards a better understanding of the evolution of human technology. We tested Goffin's cockatoos on a composite tool problem, the 'Golf Club Task', that requires the use of two objects in combination (one used to control the free movement of a second) to get a reward. We demonstrate that these parrots can innovate composite tool use by actively controlling the position of the end effector and movement of both objects involved in a goal directed manner. The consistent use of different techniques by different subjects highlights the innovative nature of the individual solutions. To test whether the solution could be socially transmitted, we conducted a second study, which provided only tentative evidence for emulative learning. To our knowledge, this indicates that the cognitive preconditions for composite tool use have also evolved outside the primate lineage. [ABSTRACT FROM AUTHOR]

Respiratory kinematics are important for the regulation of voice production. Dynamic MRI is an excellent tool to study respiratory motion providing high-resolution cross-sectional images. Unfortunately, in clinical MRI systems images can only be acquired in a horizontal subject position, which does not take into account gravitational effects on the respiratory apparatus. To study the effect of body posture on respiratory kinematics during phonation, 8 singers were examined both in an open-configuration MRI with a rotatable gantry and a conventional horizontal MRI system. During dynamic MRI the subjects sang sustained tones at different pitches in both supine and upright body positions. Sagittal images of the respiratory system were obtained at 1–3 images per second, from which 6 anatomically defined distances were extracted to characterize its movements in the anterior, medium and posterior section of the diaphragm as well as the rip cage (diameter at the height of the 3rd and 5th rip) and the anterior–posterior position of the diaphragm cupola. Regardless of body position, singers maintained their general principles of respiratory kinematics with combined diaphragm and thorax muscle activation for breath support. This was achieved by expanding their chest an additional 20% during inspiration when singing in the supine position but not for sole breathing. The diaphragm was cranially displaced in supine position for both singing and breathing and its motion range increased. These results facilitate a more realistic extrapolation of research data obtained in a supine position. [ABSTRACT FROM AUTHOR]

Our recently developed prone crawl position (PCP) for radiotherapy of breast cancer patients with lymphatic involvement showed promising preliminary data and it is being optimized for clinical use. An important aspect in this process is making new, position specific delineation guidelines to ensure delineation (for treatment planning) is uniform across different centers. The existing ESTRO and PROCAB guidelines for supine position (SP) were adapted for PCP. Nine volunteers were MRI scanned in both SP and PCP. Lymph node regions were delineated in SP using the existing ESTRO and PROCAB guidelines and were then translated to PCP, based on the observed changes in reference structure position. Nine PCP patient CT scans were used to verify if the new reference structures were consistently identified and easily applicable on different patient CT scans. Based on these data, a team of specialists in anatomy, CT- and MRI radiology and radiation oncology postulated the final guidelines. By taking the ESTRO and PROCAB guidelines for SP into account and by using a relatively big number of datasets, these new PCP specific guidelines incorporate anatomical variability between patients. The guidelines are easily and consistently applicable, even for people with limited previous experience with delineations in PCP. [ABSTRACT FROM AUTHOR]

The acetabular component orientation in total hip arthroplasty is of critical importance to clinical results. Although navigation systems and surgical robots have been introduced, most surgeons still use acetabular component alignment guides. This study aimed to compare the accuracy between modern acetabular component alignment guides for the lateral position and those for the supine position. Thirteen alignment guides for the lateral position and 10 for the supine position were investigated. All the lateral position alignment guides indicated cup alignment in operative definition, and the supine position alignment guides indicated cup alignment in radiographic definition. For lateral position alignment guides, the anteversion actually indicated by the alignment guide itself was smaller than that indicated by the manufacturer by a mean of 6° (maximum, 9°), and the inclination actually indicated by alignment guides themselves was larger than that by the manufacturer (p < 0.01) by a mean of 2° (maximum, 4°). For supine position alignment guides, the inclination and anteversion indicated by the alignment guide itself were identical with those indicated by the manufacturer. The current study showed that the angles actually indicated and those stated by manufacturers were not identical for lateral position alignment guides. [ABSTRACT FROM AUTHOR]

This study explored the dosimetric difference between hypofractionated whole-breast irradiation (HFWBI) with sequential boost (SEB) and simultaneous integrated boost (SIB) based on supine and prone positions to identify the superior boost mode and superior position. Thirty breast cancer patients eligible for HFWBI after breast-conserving surgery were enrolled. All patients underwent 3DCT simulation scanning in both supine and prone positions. For the SEB-HFWBI plan, the dose prescribed for the planning target volume (PTV) of whole breast (WB) was 2.67 Gy per fraction with a total of 15 fractions, followed by a sequential boost of 3.2 Gy per fraction to the PTV of tumor bed (TB) in 3 fractions. For the SIB-HFWBI plan, the dose prescribed for the PTV of WB was 2.67 Gy per fraction with a total of 15 fractions, with a simultaneously integrated boost of 3.2 Gy per fraction to the PTV of TB with a total of 15 fractions. Regardless of the position, for the PTV of TB, the conformal index (CI) in the SIB-HFWBI plans was greater than those in the SEB-HFWBI plans (T = − 8.114, − 8.114; both P < 0.05). The CI for the PTV of WB increased significantly in the prone position relative to the supine position in both two plans(Z = − 3.340, − 3.501; all P < 0.05). The study suggested that prone SIB-HFWBI might be more suitable for postoperative radiotherapy after breast-conserving surgery for early-stage breast cancer patients. [ABSTRACT FROM AUTHOR]

Currently, no three-dimensional reference data exist for the normal coccyx in the standing position on computed tomography (CT); however, this information could have utility for evaluating patients with coccydynia and pelvic floor dysfunction. Thus, we aimed to compare coccygeal parameters in the standing versus supine positions using upright and supine CT and evaluate the effects of sex, age, and body mass index (BMI) on coccygeal movement. Thirty-two healthy volunteers underwent both upright (standing position) and conventional (supine position) CT examinations. In the standing position, the coccyx became significantly longer and straighter, with the tip of the coccyx moving backward and downward (all p < 0.001). Additionally, the coccygeal straight length (standing/supine, 37.8 ± 7.1/35.7 ± 7.0 mm) and sacrococcygeal straight length (standing/supine, 131.7 ± 11.2/125.0 ± 10.7 mm) were significantly longer in the standing position. The sacrococcygeal angle (standing/supine, 115.0 ± 10.6/105.0 ± 12.5°) was significantly larger, while the lumbosacral angle (standing/supine, 21.1 ± 5.9/25.0 ± 4.9°) was significantly smaller. The migration length of the tip of the coccyx (mean, 7.9 mm) exhibited a moderate correlation with BMI (r = 0.42, p = 0.0163). Our results may provide important clues regarding the pathogenesis of coccydynia and pelvic floor dysfunction. [ABSTRACT FROM AUTHOR]

The highly compliant nature of the neonatal chest wall is known to clinicians. However, its morphological changes have never been characterized and are especially important for a customised monitoring of respiratory diseases. Here, we show that a device applied on newborns can trace their chest boundary without the use of radiation. Such technology, which is easy to sanitise between patients, works like a smart measurement tape drawing also a digital cross section of the chest. We also show that in neonates the supine position generates a significantly different cross section compared to the lateral ones. Lastly, an unprecedented comparison between a premature neonate and a child is reported. [ABSTRACT FROM AUTHOR]

Long-duration Antarctic expeditions are characterized by isolation, confinement, and extreme environments. Here we describe the time course of cardiac autonomic modulation assessed by heart rate variability (HRV) during 14-month expeditions at the German Neumayer III station in Antarctica. Heart rate recordings were acquired in supine position in the morning at rest once before the expedition (baseline) and monthly during the expedition from February to October. The total set comprised twenty-five healthy crewmembers (n = 15 men, 38 ± 6 yrs, n = 10 women, 32 ± 6 yrs, mean ± SD). High frequency (HF) power and the ratio of low to high frequency power (LF/HF) were used as indices of vagal modulation and sympathovagal balance. HF power adjusted for baseline differences decreased significantly during the expedition, indicating a gradual reduction in vagal tone. LF/HF powers ratio progressively shifted toward a sympathetic predominance reaching statistical significance in the final trimester (August to October) relative to the first trimester (February to April). This effect was particularly pronounced in women. The depression of cardio-vagal tone and the shift toward a sympathetic predominance observed throughout the overwintering suggest a long-term cardiac autonomic modulation in response to isolation and confinement during Antartic overwintering. [ABSTRACT FROM AUTHOR]

This study examined whether forced postural change from prone to supine during toddlers' nap, a preventative measure taken in Japan for sudden unexplained death in childhood (SUDC), disturbs toddlers' sleep. When the "Back to Sleep" campaign (BSC) was introduced to Japan in 1996, its recommendations were also applied to infants aged 1 year old and over with the expectation that the BSC recommendations may also contribute to a decrease in the occurrence rate of SUDC. Since then, Japanese nurseries have routinely conducted sleeping position checks and positional adjustments of toddlers every 5–10 min during naps. A total of 52 toddlers (age 18.4 ± 3.3 months, means ± SD) were continuously monitored for 8 h during daytime at nursery schools for wake-sleep status and body position (prone, supine and lateral) with actigraphs and 3-orthogonal-axis accelerometers. Out of the 52 toddlers, 24 toddlers adopted prone positions during naps, which were adjusted by nursery staff back to supine. When nursery staff manually changed the toddlers position from prone to supine, the toddlers either did not wake or woke only briefly (3.1 ± 4.9 min) and returned to sleep soon after the positional change. Our study indicates that manual change of toddlers' sleeping position from prone to supine, a potential SUDC prevention method, does not disturb toddlers' sleep during their naps. [ABSTRACT FROM AUTHOR]

We quantitatively evaluated breast tumor movement and volume changes between magnetic resonance imaging (MRI) scans in prone and supine positions. Twenty-seven breast tumor patients who received neoadjuvant systemic therapy (NST) for breast-conserving surgery were studied. Before and after NST, MRI scans in prone and supine positions were performed immediately. Tumor segmentation, volume, and position of tumors were evaluated in both positions. Average tumor volumes in prone and supine positions did not significantly differ (p = 0.877). Tumor movement from prone to supine positions from the origin of the bottom center of the sternum was strongly correlated with the distance from the tumor center to the chest wall (r = 0.669; p < 0.05). Tumor changes from prone to supine positions measured from the origin of the nipple depended on the location of the tumor in the breast. The prone-to-supine movement of all tumors from the origin of the bottom center of the sternum tended to move outward from the sagittal centerline of the body on the coronal plane, to the inside of the body on the sagittal plane, and outward and downward close to the body on the axial plane, which might help in planning operations using prone MRI in supine-position breast cancer surgery. [ABSTRACT FROM AUTHOR]

The purpose of study was to evaluate the perioperative lung ultrasound findings of patients undergoing scoliosis correction. LUS examination was performed examined three 3 times for each patient: 20 min after starting mechanical ventilation of the lungs(preoperative), after surgery when the patient was placed in the supine position(postoperative), and 20 min after arrival in the post-anaesthesia care unit. Arterial blood gas analyses, mechanical ventilation parameters, peripheral oxygen saturation(SpO2) were also checked. Twenty-six patients completed the study. The changes of LUS score(20 min) was significantly negatively correlated with the partial pressure of arterial oxygen(PaO2)/fraction of inspired oxygen(FiO2) ratio change(P = 0.039, r = −0.40). The change in mean convex side LUS score was significantly greater than that of the concave side as determined by two-factor repeated measures analysis of variance(p = 0.001). Multiple regression analysis revealed perioperative LUS change was the significant factor related to the oxygen index change (p = 0.042). One case of pneumothorax was diagnosed and pleural thickening more than 5 mm was detected in 8 patients and five patients of those were diagnosed pleural effusion and performed thoracentesis after surgery. Postoperative increase of LUS score was related with deteriorating of oxygenation at one day after surgery, and it suggests that lung ultrasound allows prediction of postoperative hypoxia and facilitates the diagnosis of pulmonary complications at operation room in AIS patients. [ABSTRACT FROM AUTHOR]