Averaging Procedure Research Articles

Studies of stationary features in jets: BL Lacertae

Context. High-resolution very long baseline interferometry observations have revealed a quasi-stationary component (QSC) in the relativistic jets of many blazars, which represents a standing recollimation shock. VLBA monitoring of the BL Lacertae jet at 15 GHz shows the QSC at a projected distance of about 0.26 mas from the radio core. Aims. We study the trajectory and kinematics of the QSC in BL Lacertae on sub-parsec scales using 15 GHz VLBA data of 164 observations over 20 years from the MOJAVE program and 2 cm VLBA Survey. Methods. To reconstruct the QSC’s intrinsic trajectory, we used moving average and trajectory refinement procedures to smooth out the effects of core displacement and account for QSC positioning errors. Results. We identified 22 QSC reversal patterns with a frequency of ∼1.5 per year. Most reversals have an acute angle < 90° and a few have a loop-shaped or arc-shaped trajectory. Where observed, combinations of reversals show reversible and quasi-oscillatory motion. We propose a model in which a relativistic transverse wave passes through the QSC, generating a short-lived reverse motion, similar to the transverse motion of a seagull on a wave. According to the model, relativistic waves are generated upstream and the reverse motion of the QSC is governed by the amplitude, velocity, and tilt of the wave as it passes through. The apparent superluminal speeds of the QSC (∼2 c) are then due to the relativistic speed of the jet’s transverse wave (< 0.3 c in the host galaxy rest frame) combined with the relativistic motion towards the observer. The measured superluminal speeds of the QSC indirectly indicate the presence of relativistic transverse waves, and the size of the QSC scattering on the sky is proportional to the maximum amplitude of the wave. We find that most of the transverse waves are twisted in space. In the active state of the jet, the directions of the twisting waves are random, similar to the behaviour of the wave in a high-pressure hose, while in the jet stable state, the wave makes quasi-oscillations with regular twisting. Conclusions. The study of QSC dynamics in BL Lac-type blazars is important for evaluating the physical characteristics of relativistic transverse jet waves. The latter have important implications for jet physics and open up possibilities for modelling the physical conditions and location in the jet necessary for the excitation of relativistic transverse waves.

Multiphoton Microscopy: A Feasability Study to Explore the Potential Intraoperative Tool for TURBT Diagnosis

Background: Multiphoton microscopy (MPM) is a nonlinear optical imaging technology, allowing process-free imaging of fresh tissue up to a depth of 0.5 mm, with a combined signal of autofluorescence and second harmonic generation. The absence of bladder muscle in a transurethral resection of bladder tumor (TURBT) increases risk of residual disease, recurrence, and understaging, and an intraoperative assessment of resection depth and margins may avoid unnecessary second TURBTs. Objective: The objective of this study was to test the feasibility of MPM in the real-time detection of bladder muscle in cold cup biopsies of patients undergoing TURBT. Methods: This was a prospective feasibility study. Cold cup biopsies were taken intraoperatively from the resection bed during TURBT. Tissue was stored in phosphate buffered saline solution combined with fluorescent dyes (orange acridine and rhodamine). MPM imaging of the tissue was performed first, with z stack images of 100 µm maximum depth for 3D imaging. After MPM imaging, tissue was fixed in formalin and sent to the biorepository for standard histopathology. A descriptive analysis was performed between MPM tissue detection and final histopathology results. Results: Ten patients were included in this pilot study. Tissue was properly imaged for all patients, although 3 of them had artifacts, and we detected 5 times muscularis propria on MPM imaging. MPM average procedure time from biopsy to formalin fixation (MPM imaging) was 16.2 minutes (12-20 minutes). On final pathology, resection depth was correctly performed for only 4 patients of 10 (resection including bladder muscle). We found an 80% sensitivity on resection depth between first layer identified on MPM and final pathology (8/10 patients) and 100% correlation with final histopathology in specimens for the assessment of detrusor muscle. Conclusions: This study supports the use of MPM as a novel intraoperative tool which can evaluate cold cup biopsies during TURBT for resection depth and potentially avoid unnecessary second look procedure.

Evaluating efficacy and safety of a novel registration-free CT-guided needle biopsy navigation system (RC 120): A multicenter, prospective clinical trial

BackgroundCurrent percutaneous transthoracic needle biopsies (PTNB) navigation systems present challenges due to additional steps and limitations on the operating environment. Research QuestionWe developed a novel, registration-free navigation system for swift and precise CT-guided PTNB, eliminating the need for body surface markers and intraoperative registration. This study assesses its efficacy and safety. MethodsA prospective study was conducted on participants aged 18–80 years prepared for PTNB at two clinical centers, from December 2021 to August 2022. The primary endpoint was the success rate of biopsies within 2 needle adjustments, and the secondary endpoint was the success rate within a single adjustment. Safety endpoints were defined by adverse events occurrence. ResultsThe study included 98 patients (median age, 64 years, IQR 54–69 years, 71 men). The primary endpoint achieved a biopsy success rate of 98.98 %, and the secondary endpoint demonstrated 97.96 %. The overall success rate was 98.98 %, significantly exceeding the target value of 85 % (P < 0.0001). The median number of CT scans was 3, significantly fewer than predicted for the manual puncture scheme [3 (IQR 3–3) to 8 (IQR 6–8), P < 0.0001]. The average procedure duration was 18.0 min (IQR: 14.0–29.0 min). The most common adverse events were hemorrhage (14 instances) and pneumothorax (8 instances). Other adverse events included elevated blood pressure, hemoptysis, and other common events. InterpretationOur registration-free navigation system proved to be an effective and safe system for assisting percutaneous lung biopsies in clinical practice.

Prevention of left ventricular outflow tract obstruction in transapical mitral valve replacement: the MitraCut procedure.

The MitraCut procedure employs beating heart transapical (TA) cannulation and endoscopic scissors for dividing the anterior mitral leaflet (AML) to prevent left ventricular outflow tract (LVOT) obstruction in transapical transcatheter mitral valve replacement (TA-TMVR). We present the first multicentre experience of the MitraCut procedure prior to TA-TMVR to prevent LVOT obstruction. In 6 European centres, the clinical outcomes of all 13 high-risk patients who had undergone the MitraCut procedure during TA-TMVR procedures were retrospectively reviewed regarding technical success, procedural details and outcome. The MitraCut procedure was successfully completed in 11 patients with 1 cutting attempt, while 2 patients had 2 cutting attempts, with an average procedure duration of 9.0±5.4 min. No patient demonstrated postoperative LVOT obstruction, and all mitral valve (MV) prostheses were competent throughout the follow-up period. However, 1 patient developed a MitraCut-related paravalvular leak (PVL; technical success rate: 12/13). The mean LVOT gradient was 3.9±4.4 mmHg directly after valve expansion and 3.6±3.1 mmHg at follow-up. In-hospital and 30-day mortality were 0%. One patient experiencing MitraCut-related PVL was successfully treated by interventional PVL closure (reintervention rate: n=1). One patient died at 47 days due to cardiac arrhythmia, unrelated to the AML-directed procedure. The mean follow-up at the time of data analysis was 52±34 days. The MitraCut procedure was effective and reproducible for preventing potential LVOT obstruction in TA-TMVR patients during its initial exploration in 6 European hospitals. Considerations regarding the scissors' characteristics, their handling and cut length are mandatory for safe performance of the procedure.

The Bałaban variational problem in the non-linear sigma model

The minimization of the action of a QFT with a constraint dictated by the block averaging procedure is an important part of Bałaban’s approach to renormalization. It is particularly interesting for QFTs with non-trivial target spaces, such as gauge theories or non-linear sigma models on a lattice. We analyze this step for the [Formula: see text] non-linear sigma model in two dimensions and demonstrate, in this case, how various ingredients of Bałaban’s approach play together. First, using variational calculus on Lie groups, the equation for the critical point is derived. Then, this non-linear equation is solved by the Banach contraction mapping theorem. This step requires detailed control of lattice Green functions and their integral kernels via random walk expansions.

Can Whole-heart Tissue Engineering Products by Recellularization from Scaffolds Be Utilized on Humans in the Next Ten Years?

Diseases like organ failure lead to irreversible damage to our body, making organ transplantation the only treatment. However, though organ transplantation may be an effective treatment, problems of organ shortage and post-transplantation immune rejection still remain unresolved, making the development of alternative technologies vital. Organ regeneration is, therefore, a promising treatment as it aims to lower the chance of immune responses and may potentially solve the issue of organ shortage. An average procedure of organ regeneration has two steps: decellularization and recellularization. Decellularization techniques include physical, chemical, and enzymatic treatments, and these methods are often combined to maximize cell depletion, turning the organ into an extracellular matrix scaffold and minimizing the chances of immune rejection. Recellularization is the process of repopulating the scaffold with patient-specific cells, and is often completed through using perfusion systems by performing vascular perfusion and intramyocardial injections with the help of a bioreactor. This article explains the concept of whole-heart regeneration and assesses different methods of decellularization and recellularization to find the treatment with the highest efficacy and efficiency, while also conducting a case study on cultured epidermal autografts and primary research, in the form of a questionnaire, to look at the social acceptance of this technology, estimate the progress of whole-heart regeneration, and discuss its limitations.

A multi-center study on the use of lidocaine thermogel for pain control in outpatient operative hysteroscopy

ObjectivesThis study aimed to explore the use of an anesthetic lidocaine thermogel in outpatient operative hysteroscopies. Specifically, it assessed the safety, tolerability, and ease of use of the gel, as well as its potential for pain reduction during the procedure. Study designThis was a multicenter observational study conducted in 9 gynecological units between March 2023 and January 2024. The study included adult women scheduled for outpatient operative hysteroscopies, excluding those with hypersensitivity to the product or recent participation in other clinical studies. The target sample size was 60 to account for potential dropouts. Data collection was electronic, and SPSS was used for analysis. The study assessed visibility conditions, procedure duration, pain scores at different stages of the procedure, and adverse event frequency. Statistical analyses utilized descriptive statistics, Student’s t-tests, Wilcoxon and Friedman tests, and Chi-Square or Fisher tests as appropriate. Binary logistic regression was applied to identify factors influencing gel volume. ResultsAll 60 participants met the inclusion criteria. The mean age was 45.5 (SD 8.8) years, with a mean BMI of 27.0 (SD 5.6) kg/m2. Medical histories were reported in 46.7% of participants, and 50% had undergone previous gynecological surgeries. Prior to the procedure, 51.8% of participants took analgesics. The average procedure duration was 13.9 (SD 15.1) minutes. Pain scores were collected at different stages of the procedure, with median VAS scores ranging from 0 to 5 out of 10. In 50% of cases, the quality of vision during the procedure was rated 9 or higher on a 10-point scale. The full recommended dose of thermogel was administered in 91.7% of cases. The mean gel volume used was 7.0 (SD 1.9) milliliters. Regression analysis showed that younger age and a history of abortions or childbirth were significantly associated with higher gel volume use. ConclusionsThe anesthetic thermogel demonstrated effectiveness in managing pain during outpatient operative hysteroscopies, with median pain scores ranging from 0 to 5 out of 10 across different stages of the procedure. The gel showed a favorable safety profile, with only 15% of participants reporting adverse effects, all of which were minor and resolved satisfactorily. The high rate of complete gel application (91.7% of cases) and positive physician feedback suggest good tolerability and ease of use. Further research is recommended to evaluate the gel’s efficacy in other gynecological procedures and to optimize application protocols based on patient-specific factors such as age and reproductive history.

Higher-order stochastic averaging for investigating a vehicle suspension system with nonlinear damping and stiffness

The paper deals with a quarter-car model with nonlinear damping and stiffness under white noise base excitation using the higher-order stochastic averaging method for analyzing approximate responses. Recently, a novel higher-order averaging procedure has been developed to find analytically the first-, second-, and third-order stationary joint probability density functions (PDF) of amplitude and full phase by solving the corresponding Fokker-Planck-Kolmogorov (FPK) equation, and it will be extended to the nonlinear quarter-car model. Accordingly, the mean-square responses such as the displacement, and velocity of the sprung mass can be obtained analytically. The influences of excitation intensity on the dynamic responses, as well as the variations of linear and nonlinear damping, are analyzed. A very satisfactory agreement is found between the accuracy of the solutions corresponding to higher-order stochastic averaging and that of Monte Carlo simulation.

Effective elasto‐(visco)plastic coefficients of a bi‐phasic composite material with scale‐dependent size effects

We employ the theory of asymptotic homogenization (AH) to study the elasto‐plastic behavior of a composite medium comprising two solid phases, separated by a sharp interface and characterized by mechanical properties, such as elastic coefficients and “initial yield stresses” (i.e., a threshold stress above which remodeling is triggered), that may differ up to several orders of magnitude. We speak of “plastic” behavior because we have in mind a material behavior that, to a certain extent, resembles plasticity, although, for biological systems, it embraces a much wider class of inelastic phenomena. In particular, we are interested in studying the influence of gradient effects in the remodeling variable on the homogenized mechanical properties of the composite. The jump of the mechanical properties from one phase to the other makes the composite highly heterogeneous and calls for the determination of effective properties, that is, properties that are associated with a homogenized “version” of the original composite, and that are obtained through a suitable averaging procedure. The determination of the effective properties results convenient, in particular, when it comes to the multiscale description of inelastic processes, such as remodeling in soft or hard tissues, like bones. To accomplish this task with the aid of AH, we assume that the length scale over which the heterogeneities manifest themselves is several orders of magnitude smaller than the characteristic length scale of the composite as a whole. We identify both a fine‐scale problem and a coarse‐scale problem, each of which characterizes the elasto‐plastic dynamics of the composite at the corresponding scale, and we discuss how they are reciprocally coupled through a transfer of information from one scale to the other. In particular, we highlight how the coarse‐scale plastic distortions influence the fine‐scale problem. Moreover, in the limit of negligible hysteresis effects, we individuate two viscoplastic effective coefficients that encode the information of the two‐scale nature of the composite medium in the upscaled equations. Finally, to deal with a case study tractable semi‐analytically, we consider a multilayered composite material with an initial yield stress that is constant in each phase. Such investigation is meant to contribute to the constitution of a robust framework for devising the effective properties of hierarchical biological media.

Single-Port Robotic Ureteroenteric Stricture Repair: A Retrospective Cohort Review.

Introduction The objective of this study is to present a series of 16 cases utilizing single-port robot-assisted repair for ureteroenteric anastomosis stricture (UES). To our knowledge, this is the first case series recorded detailing successful single-port UES revision. Methods A retrospective review of all patients under a single surgeon undergoing single-port robotic revision of ureteroenteric stricture following radical cystectomy with urinary diversion at our institutions from September 2020 through July 2024 was performed. Patient demographics and perioperative outcomes were assessed. Results The study consisted of 3 bilateral ureteroenteric strictures and 13 unilateral strictures, more commonly on the left. Stricture length averaged 2.2 cm on the left and 2.1 cm on the right. Surgeries were performed by a single surgeon using the da Vinci SP surgical system (Intuitive Surgical, Sunnyvale, California, US). The type of stricture repair included excision and primary anastomosis (EPA) with Bricker or Wallace reconstruction or Heineke-Mikulicz (HM) repair, although one case involved the necessity of revision ileocalycostomy. Two of the 16 cases were converted from robotic to open due to extensive adhesions. The average procedure length was 265 minutes (148-440). Length of stay (LOS) ranged from 0-46 days, averaging 4.9 days. There were five postoperative complications encountered including two seromas, two incisional hernias, and an episode of urosepsis. Pre- and postoperative changes in creatinine level ranged from -0.26 to 0.3 mg/dL. No renal units were lost.No patients were readmitted following initial surgical discharge. All patientsreturned for follow-up; none required repeat intervention. Conclusion SP robotic repair of ureteroenteric anastomoses is safe and feasible. The risk of complications is low with a high chance of success and possibly a lower length of stay;more research is warranted.

Contrast enhanced mammography (CEM) guided biopsy using a prone table: A retrospective analysis of the preliminary experience in a single CEM referral center

BackgroundThis study evaluates the procedural efficacy and patient experience of Contrast Enhanced Mammography (CEM)-guided biopsies performed in a prone position using the Giotto Class 30,000 system. The emphasis is on the procedural advantages and clinical outcomes for “enhancing-only lesions” (EOLs). MethodsA retrospective analysis of 524 CEM examinations conducted from December 2023 to June 2024 at a tertiary referral center was performed. Patients referred for pre-surgical staging or evaluation of inconclusive findings from conventional imaging were included. The study utilized dual-energy imaging and vacuum-assisted biopsy techniques, focusing on patients with at least one EOL identified in their initial CEM. Exclusions were based on the absence of a primary or follow-up CEM conducted at our facility Endpoints of this work included procedure efficiency which was evaluated in terms of technical success (biopsy completion with adequate sampling), dose distribution and timing and detection of additional lesions and patients’ comfort evaluation, based on the rate of complications (hematomas) and procedure interruption due to patients’ specific request or fainting events. ResultsAmong the evaluated cases, 37 EOLs were biopsied. The average procedure time was 15.8 min. Biopsies were successfully completed in 100% of cases. However, complications occurred in 27% of cases, primarily as hematomas and a significant histological finding rate of 97.3% was recorded. ConclusionsThe use of the Giotto Class 30,000 system for CEM-guided biopsies in a prone position demonstrated high procedural success and was well-tolerated by patients, highlighting its potential to enhance procedural comfort and efficiency. These preliminary results validate the innovative approach, though further studies are required to solidify these findings and explore long-term outcomes.

Graduating vascular surgery trainee proficiency in endovascular and open peripheral revascularization procedures

BackgroundEndovascular interventions for peripheral artery disease have increased in prevalence over time given the inherent benefits of minimally invasive approaches. Although it is essential that vascular surgery graduates are facile with endovascular techniques, the results of the BEST-CLI (Best Endovascular vs. Best Surgical Therapy in Patients With Critical Limb Ischemia) trial highlight the equivalent importance of ensuring trainee competence in open skills. Recent studies demonstrate increasing case volume of both endovascular and open procedures during vascular surgery training. Case volume is merely a surrogate marker for competence, however, and the objective competence attained by trainees at the time of graduation is unknown. We sought to investigate operative autonomy and competence of graduating vascular surgery trainees performing endovascular as compared with open peripheral vascular revascularization procedures. MethodsOperative performance and autonomy ratings for infrainguinal endovascular and open revascularizations from the Society for Improving Professional Learning Operative application database were collected for all vascular surgery participating institutions from 2018 to 2023. The distribution for autonomy and performance ratings were determined by training level for endovascular and open procedures, respectively. Mixed effects logistic regressions were conducted to estimate the predictive association between procedure type and autonomy and performance assessment, adjusting for training level and case complexity. Subsequently, the estimated model was applied to predict the probability of a graduating trainee being rated as meaningfully autonomous or competent while performing endovascular and open procedures across various case complexities. ResultsSixty-nine residents from 23 programs (12 fellowship, 11 residency) were assessed on 706 revascularization procedures (n = 383 endovascular; n = 323 open). When controlling for training level and case complexity, there were no differences in autonomy (odds ratio [OR], 1.11; 95% confidence interval [CI], 0.62-1.99) or competency assessment (OR, 0.86; 95% CI, 0.46-1.59) for endovascular, as compared with open, peripheral revascularization procedures. For average complexity procedures, the predicted probability of a trainee being assessed as competent and autonomous at the time of graduation was high (competent: 88% endovascular, 86% open; autonomous: 96% endovascular, 97% open). The predicted probability of competence and autonomy for complex procedures was lower, but remained similar between groups (competent: 73% endovascular, 70% open; autonomous: 92% endovascular, 92% open). ConclusionsThere is no difference in the graduating level of autonomy and competence of endovascular as compared with open peripheral revascularization procedures for vascular surgery trainees. These findings suggest that vascular surgery trainees enter independent practice with adequate proficiency to use the full scope of techniques to care for patients requiring peripheral revascularization procedures.

Optimal directed acyclic graph federated learning model for energy-efficient IoT communication networks

Federated learning (FL) stimulates distributed on-device computation systems to process an optimum technique efficiency by communicating local process upgrades and global method distribution from aggregation averaging procedure. On-device FL is a standard application in wireless environments, with several mobile devices participating as nodes in the FL network. Managing extensive multi-dimensional process upgrades and resource-constrained computations in large-scale heterogeneous IoT cellular networks can be challenging. This article introduces a Lifetime Maximization using Optimal Directed Acyclic Graph Federated Learning in IoT Communication Networks (LM-ODAGFL) technique. The proposed LM-ODAGFL technique utilizes FL and metaheuristic optimization algorithms for energy-effective IoT networks. The Direct Acyclic Graph (DAG) model addresses device asynchrony in FL while minimizing additional resource usage. The Archimedes Optimization Algorithm (AOA) is designed to optimize the DAG model by reducing both user energy consumption and the training loss of the FL model. The performance validation of the LM-ODAGFL technique is performed by utilizing a series of experimentations. The obtained results of the LM-ODAGFL model demonstrate superior performance by consuming significantly less energy than SDAGFL and ESDAGFL, with values ranging from 0.373 to 0.485 kJ per round on the FMNIST-Clustered dataset and 16.27 to 20.34 kJ per round on the Poets dataset, compared to 0.000 to 1.442 kJ and 0.00 to 63.89 kJ respectively.

Study on Unguided Temporary Pacing Via the Jugular Vein at the Mohamed VI University Hospital of Marrakech: Safety, Effectiveness and Practicability

This study evaluates the safety, effectiveness, and feasibility of unguided temporary pacemaker insertion in 348 patients at the Mohamed VI University Hospital of Marrakech. The procedure was performed by cardiology residents and showed a high success rate of 99.71%, with successful access to the right internal jugular vein in 89.66% of cases. The majority of patients (66.38%) achieved venous access on the first attempt, with an average procedure time of 11.5 ± 2.1 minutes. Minor complications were observed in 10.63% of patients, including local hematomas (3.45%), accidental arterial punctures (2.30%), pneumothorax (1.15%), and other issues such as local infections and non-sustained ventricular tachycardia. No deaths attributable to the procedure were reported. The clinical significance of this study lies in its demonstration that unguided temporary pacemaker insertion is a safe and effective alternative in resource-limited settings, reducing treatment delays and potentially lowering mortality among patients requiring temporary cardiac pacing. Based on these results, it is recommended to encourage clinicians in primary and secondary healthcare settings to adopt this approach to improve access to urgent cardiac care in under-resourced regions.

Simultaneous Percutaneous Coronary Intervention (PCI) and Endovascular Aneurysm Repair (EVAR): A Preliminary Report.

Background: Performing percutaneous coronary intervention (PCI) and endovascular aneurysm repair (EVAR) at the same time represents a groundbreaking development in the multidisciplinary treatment of cardiovascular disease. This combined PCI-EVAR approach bridges a critical gap by offering treatment for patients who have both coronary artery disease and aortic aneurysms. This innovative strategy exemplifies the evolving landscape of cardiovascular care, providing a new solution for complex clinical situations that previously required separate procedures. Methods: Six patients with critical coronary artery lesions and asymptomatic infrarenal aortic aneurysms (AAAs) ≥ 6 cm diameter, as well as one patient with critical coronary artery lesions and endoleak type 1A with aneurysms ≥ 6 cm, underwent simultaneous coronary artery revascularization through percutaneous intervention (PCI) and endovascular aneurysm repair (EVAR). The occurrence of any intraoperative or postoperative complication was considered to be the primary endpoint of the study, including the abortion or failure of either PCI or EVAR, bleeding requiring a conversion to open surgical procedures, the failure of local anesthesia, postoperative myocardial or lower limb ischemia, and a postoperative serum creatinine level of >125 mmol/L or of >180 mmol/L in patients affected by chronic renal failure. The overall length of the procedure, X-ray exposure, the quantity of iodine contrast medium administered, and the length of recovery were considered to be secondary endpoints. Results: Postoperative complications included two episodes of acute renal failure in the two patients already affected by chronic renal failure, which were easily resolved with adequate daily hydration and the elimination of nephrotoxic drugs. In no cases did cardiac ischemia or lower limb ischemia occur. The average procedure duration was 198 min (range: 180-240 min), the average fluoroscopy duration was 41.7 min (range: 35-50 min), the average amount of iodinated contrast medium was 34.8 mL (range: 30-40 mL), and the mean length of hospitalization was 2.7 days (range: 2-5 days). Conclusions: In selected patients, this surgical approach has demonstrated safety, reduced hospitalization times, minimized risks associated with complications from the untreated condition if procedures were performed at different times, and facilitated the effective management of intraoperative complications due to the presence of a multidisciplinary team. However, the limited number of patients necessitates further research.

Augmented reality for point-of-care ultrasound-guided vascular access in pediatric patients using Microsoft HoloLens 2: a preliminary evaluation.

Conventional ultrasound-guided vascular access procedures are challenging due to the need for anatomical understanding, precise needle manipulation, and hand-eye coordination. Recently, augmented reality (AR)-based guidance has emerged as an aid to improve procedural efficiency and potential outcomes. However, its application in pediatric vascular access has not been comprehensively evaluated. We developed an AR ultrasound application, HoloUS, using the Microsoft HoloLens 2 to display live ultrasound images directly in the proceduralist's field of view. We presented our evaluation of the effect of using the Microsoft HoloLens 2 for point-of-care ultrasound (POCUS)-guided vascular access in 30 pediatric patients. A custom software module was developed on a tablet capable of capturing the moving ultrasound image from any ultrasound machine's screen. The captured image was compressed and sent to the HoloLens 2 via a hotspot without needing Internet access. On the HoloLens 2, we developed a custom software module to receive, decompress, and display the live ultrasound image. Hand gesture and voice command features were implemented for the user to reposition, resize, and change the gain and the contrast of the image. We evaluated 30 (15 successful control and 12 successful interventional) cases completed in a single-center, prospective, randomized study. The mean overall rendering latency and the rendering frame rate of the HoloUS application were 139.30ms and 30 frames per second, respectively. The average procedure completion time was 17.3% shorter using AR guidance. The numbers of puncture attempts and needle redirections were similar between the two groups, and the number of head adjustments was minimal in the interventional group. We presented our evaluation of the results from the first study using the Microsoft HoloLens 2 that investigates AR-based POCUS-guided vascular access in pediatric patients. Our evaluation confirmed clinical feasibility and potential improvement in procedural efficiency.

Use of Snare Tip Endoscopic Submucosal Dissection in the Endoluminal Management of Complex Colon Lesions.

Endoscopic submucosal dissection for advanced colon lesions is typically performed with specialized and costly endoscopic knives, potentially limiting accessibility and increasing procedural cost. Alternatively, the tip of an endoscopic snare, which is inexpensive and universally available, has demonstrated safe and efficient use in gastric lesions but lacks sufficient data for use in colon lesions. This study aimed to assess patient outcomes following endoscopic submucosal dissection of advanced colon lesions using the endoscopic snare tip. A retrospective review of a prospectively maintained database at a single tertiary care center was conducted. This study was conducted at a single tertiary care center. Adult patients with colon lesions that were not amenable to snare polypectomy were evaluated for endoscopic submucosal dissection. Snare tip resection was performed in select patients with lesions that lifted adequately after submucosal injection. Patients who underwent hybrid resections with endoscopic mucosal dissection were excluded. En bloc resection rates, operative time, perioperative complications, and short-term outcomes such as length of stay and lesion recurrence on follow-up colonoscopy were evaluated. A total of 121 patients underwent snare tip endoscopic submucosal dissection, with a mean lesion size of 28.8 ± 9.84 mm. Most procedures were performed in the endoscopy suite (81.8%). The en bloc resection rate was 81.8% with an average procedure time of 37.1 ± 29.8 min. There were two perforations (1.70%), one of which was managed operatively. Recurrence occurred in 6 patients (7.89%) at the time of follow-up colonoscopy. This study was retrospective, conducted by two skilled endoscopists with experience in endoscopic resection, and had short-term follow up. Snare tip endoscopic submucosal dissection for advanced colon lesions demonstrates satisfactory short-term outcomes, suggesting its potential as a safe and accessible alternative to specialized knives, thereby possibly enhancing adoption of endoscopic resection and improving patient accessibility. See Video Abstract.

A modular finite element approach to saturated poroelasticity dynamics: Fluid–solid coupling with Neo-Hookean material and incompressible flow

Several methods have been developed to model the dynamic behavior of saturated porous media. However, most of them are suitable only for small strain and small displacement problems and are built in a monolithic way, so that individual improvements in the solution of the solid or fluid phases can be difficult. This study shows a macroscopic approach through a partitioned fluid–solid coupling, in which the skeleton solid is considered to behave as a Neo-Hookean material and the interstitial flow is incompressible following the Stokes–Brinkman model. The porous solid is numerically modeled with a total Lagrangian position-based finite element formulation, while an Arbitrary Lagrangian-Eulerian stabilized finite element approach is employed for the porous medium flow dynamics. In both fields, an averaging procedure is applied to homogenize the problem, resulting in a macroscopic continuous phase. The solid and fluid homogenized domains are overlapped and strongly coupled, based on a block-iterative solution scheme. Two-dimensional simulations of wave propagation in saturated porous media are employed to validate the proposed formulation through a comprehensive comparison with analytical and numerical results from the literature. The analyses underscore the proposed formulation as a robust and precise modular approach for addressing dynamic problems in poroelasticity.

Clinical experience of pulmonary vein isolation via single transseptal puncture in atrial fibrillation patients: Comprehensive characterization and follow-up

BackgroundAtrial fibrillation is the most commonly observed cardiac rhythm disorder. Pulmonary vein isolation (PVI) is an effective treatment option to maintain sinus rhythm. This study evaluates the safety, efficacy, clinical outcomes and radiation exposures using a standardized single transseptal puncture (STP)-strategy. MethodsWe analyzed data from patients who underwent our STP-ablation technique with transesophageal echocardiography (TEE) guidance at a university hospital and a regional tertiary health center in Switzerland between January 1, 2017, and May 30, 2022. Collected data included demographics, symptoms, echocardiography results, procedural details, complications and outcomes. Mean follow-up time was 21.4 ± 16 months. ResultsThe study population included 304 patients with a median age of 67 years, who had at least one ablation using our STP-approach. Among these, 248 (82 %) patients underwent de novo PVI with this technique. Ablation was successful in all patients with isolation of all pulmonary veins, with an average procedure duration of 120 min and an average fluoroscopy time of 3 min, resulting in a mean X-ray dose of 252 cGy × cm2. TEE guidance was performed in 235 (95 %) patients. During the first intervention, 17 complications occurred in 13 patients (5 %). After the first PVI, 135 (54 %) patients experienced no recurrence during the follow-up period. The one-year recurrence rate for atrial fibrillation requiring therapy was 30 %. ConclusionOur STP- approach demonstrated comparable success rates to traditional methods, with similar procedural durations, low radiation exposure and a low complication rate. Therefore, this method may offer procedural, economic and safety benefits without compromising efficacy or safety.

Exploring versatile applications of a vacuum-assisted bone harvester in orthopedic surgery

BackgroundOrthopedic procedures often require removing bone or pathological tissue, with traditional methods involving instruments like curettes and rongeurs. However, these methods can be time-consuming and lead to increased blood loss. To mitigate these side effects, vacuum-assisted tools have been developed to aid in tissue removal. These devices enable surgeons to suction tissue without discarding it, potentially improving outcomes in conditions such as osteomyelitis or tumor removal while enabling collection of the material for downstream applications. Despite limited research, vacuum-assisted devices show promise beyond bone marrow harvesting. This study assesses infection and clearance rates, estimated blood loss, and total procedure time associated with the use of vacuum-assisted tissue removal, with a goal to understand if these devices can be used for tissue removal across a variety of pathologic conditions.MethodsA retrospective cohort study was conducted on patients undergoing orthopedic procedures with the Avitus® Bone Harvester repurposed from its original design from December 1, 2021, to July 1, 2023. Procedures were categorized into oncology, and debridement for infection cases. Infection cases were further categorized into those secondary to trauma and those involving primary infections (osteomyelitis and periprosthetic joint infection). Clinical variables, including demographics, intraoperative details, complications, and follow-up, were reviewed. Statistical analysis included descriptive statistics computed with R Studio.ResultsThe study included 44 patients, with debridement for infection cases being the most common (primary infection: 45.5%; infection secondary to trauma: 18.1%), followed by oncology cases (36.4%). In all oncology cases, a definitive diagnosis was established using the device, and no post-operative infections were reported. The infection clearance rate was 85.0% for primary infection cases and 50.0% for cases of infection following trauma. Across the entire cohort, the average blood loss was 314.52 mL (sd: 486.74), and the average total procedure time was 160.93 min (sd: 91.07). The overall reoperation rate was 47.7%, with an unplanned reoperation rate of 11.4%.ConclusionThe vacuum-assisted bone harvester was effectively utilized in a wide range of debridement and curettage procedures across diverse orthopedic surgeries. In oncology cases, the device enabled effective tissue removal with comparable recurrence rates, demonstrating its potential to minimize contamination while preserving tissue for accurate diagnoses. Additionally, a high rate of osteomyelitis eradication was observed in debridement for primary infection cases (85%). Despite the relatively high reoperation rate of 47.7%, it is crucial to interpret this figure within the context of the varied reasons for reoperation. Many of these reoperations were planned as part of a staged approach to treatment or were unrelated to the device's performance. It is crucial to acknowledge that isolating the device's contribution to these results can be difficult. The utilization of the device should be guided by considerations of cost-effectiveness and patient-specific risk factors.