Operator Inexperience Research Articles

A machine learning framework to adjust for learning effects in medical device safety evaluation.

Traditional methods for medical device post-market surveillance often fail to accurately account for operator learning effects, leading to biased assessments of device safety. These methods struggle with non-linearity, complex learning curves, and time-varying covariates, such as physician experience. To address these limitations, we sought to develop a machine learning (ML) framework to detect and adjust for operator learning effects. A gradient-boosted decision tree ML method was used to analyze synthetic datasets that replicate the complexity of clinical scenarios involving high-risk medical devices. We designed this process to detect learning effects using a risk-adjusted cumulative sum method, quantify the excess adverse event rate attributable to operator inexperience, and adjust for these alongside patient factors in evaluating device safety signals. To maintain integrity, we employed blinding between data generation and analysis teams. Synthetic data used underlying distributions and patient feature correlations based on clinical data from the Department of Veterans Affairs between 2005 and 2012. We generated 2494 synthetic datasets with widely varying characteristics including number of patient features, operators and institutions, and the operator learning form. Each dataset contained a hypothetical study device, Device B, and a reference device, Device A. We evaluated accuracy in identifying learning effects and identifying and estimating the strength of the device safety signal. Our approach also evaluated different clinically relevant thresholds for safety signal detection. Our framework accurately identified the presence or absence of learning effects in 93.6% of datasets and correctly determined device safety signals in 93.4% of cases. The estimated device odds ratios' 95% confidence intervals were accurately aligned with the specified ratios in 94.7% of datasets. In contrast, a comparative model excluding operator learning effects significantly underperformed in detecting device signals and in accuracy. Notably, our framework achieved 100% specificity for clinically relevant safety signal thresholds, although sensitivity varied with the threshold applied. A machine learning framework, tailored for the complexities of post-market device evaluation, may provide superior performance compared to standard parametric techniques when operator learning is present. Demonstrating the capacity of ML to overcome complex evaluative challenges, our framework addresses the limitations of traditional statistical methods in current post-market surveillance processes. By offering a reliable means to detect and adjust for learning effects, it may significantly improve medical device safety evaluation.

Optical microscopy evaluation of root canal filling removal by beginner operators in posterior teeth.

This study analyzed the effectiveness of root canal filling removal in lower molars performed by beginner operators using optical microscopy. A total of 55 mandibular first and second molars with mesial roots exhibiting an average curvature of 10-20° were selected based on preoperative radiographs. Instrumentation was done with ProTaper Gold (Dentsply Sirona) up to F2 (25/.08), using 2ml of 2.5% NaOCl irrigation solution after each file. Root canal obturation was performed using gutta-percha points with cold lateral condensation and Sealapex (Kerr Dental). Coronal fillings were made with composite resin and stored in distilled water for two years. Removal of the root canal fillings was performed with AF Retreatment Rotary (AFRR) and AF Blue R3 (AFBR3) (Fanta Dental Materials) under reciprocating motion with 2.5% NaOCl irrigation. Cross-sections of the coronal, middle, and apical thirds were analyzed at 40x magnification using a STEINDORFF POL microscope with a digital camera. Image analysis was conducted using Image J software, version 1.54, to determine the efficiency of root canal filling removal by percentage. Statistical analysis via one-way ANOVA revealed significant differences between distal and mesial roots (P < 0.05). Specifically, for mesial roots, the removal efficiency was 70.65% in the coronal third, 54.66% in the middle third, and 21.32% in the apical third. Significant difficulties were noted due to fractured files, calcifications, and debris accumulation in the isthmuses. The study concluded that the protocol using Fanta files demonstrated significant differences in removal efficiency correlated with root curvature, compounded by the inexperience of beginner operators. The findings highlight the challenges faced by novice practitioners in achieving effective root canal filling removal.

Determining the ideal measurement site and respiratory condition for liver transient elastography: toward clinical practice standardization

ObjectivesLiver transient elastography (TE) has been endorsed by the WHO as the first-line diagnostic tool for liver diseases. Although unreliable and invalid results caused by intercostal space (ICS)-associated factors (including excessive subcutaneous fat and a narrow ICS relative to the transducer size) and operator inexperience are not uncommon, no standard guidelines for ideal probe placement are currently available. Herein, we conducted a prospective observational study to identify an ideal measurement site and respiratory condition for TE by characterizing anatomical and biomechanical properties of the ICSs using ultrasound B-mode and elasticity imaging.MethodsIntercostal ultrasound was performed pointwise at four specific sites in 59 patients to simultaneously measure the width, stiffness, and skin‒liver capsule distance (SCD) of the ICSs over the liver, under end-inspiratory and end-expiratory conditions. Intersections between the 8th ICS and anterior axillary line, the 7th ICS and anterior axillary line, the 8th ICS and mid-axillary line, and the 7th ICS and mid-axillary line were defined as Sites 1 to 4, respectively.ResultsResults indicated that Sites 2 and 3 presented greater intercostal width; Sites 3 and 4 displayed lower intercostal stiffness; Sites 2 and 3 exhibited a shorter SCD. The ICSs were significantly wider and stiffer at end-inspiration. Additionally, the liver was more easily visualized at Sites 1 and 3.ConclusionWe recommend Site 3 for TE probe placement owing to its greater width, lower stiffness, and smaller abdominal wall thickness. Performing TE at end-inspiration is preferred to minimize transducer-rib interferences. This study paves the way toward a standardized TE examination procedure.Critical relevance statementA standardized measurement protocol for WHO-recommended liver TE was first established to improve the success and efficiency of the examination procedure.Key PointsWHO-recommended TE is unreliable or fails due to intercostal space-related factors.The 8th intercostal space on the mid-axillary line and end-inspiration are recommended.This standardized protocol aids in handling challenging cases and simplifies operational procedures.Graphical

Tips and tricks for a correct interpretation of contrast-enhanced ultrasound.

Although contrast-enhanced ultrasound (CEUS) is a widespread and easily manageable technique, image interpretation errors can occur due to the operator's inexperience and/or lack of knowledge of the frequent pitfalls, which may cause uncertain diagnosis and misdiagnosis. Indeed, knowledge of the basic physical and technical principles of ultrasound is needed both to understand sonographic image findings and to evaluate the potential and limits of the method. Like the B-mode ultrasound, the quality of the CEUS examination is also subject not only to the adequate manual skill of the operator but also to his/her deep knowledge of the technique which improves the quality of the image helping avoid misleading artifacts. In this review, the main parameters influencing a CEUS examination will be described by taking into account the most common errors and pitfalls and their possible solutions.

Endodontic Microsurgery With an Autonomous Robotic System: A Clinical Report

IntroductionEndodontic microsurgery (EMS) requires minimally invasive osteotomy and accurate root-end resection, which can be challenging in many instances. Evidence suggests that autonomous robotic systems can significantly enhance the precision of dental implantation. The aim of this case report is to introduce a novel EMS technique that employs robot-guided osteotomy and root resection procedures. MethodsA 59-year-old man was diagnosed with previously treated, symptomatic apical periodontitis in the mandibular left first molar. Patient data were used to integrate a digital model into preoperative planning software to design the surgical plan. The robotic system utilizes spatial alignment techniques for registration, guiding the robotic arm to autonomously perform a 3-mm osteotomy and root-end resection, based on the surgical plan. After completing the resection, the clinician confirmed the absence of cracks or root fractures and subsequently performed root-end preparation and filling under a microscope. ResultsTo the best of our knowledge, this case marks the first use of autonomous robotic assistance in EMS. ConclusionsUtilizing an autonomous robotic system could enable precise apicoectomy in patients with intact cortical plates, thus facilitating successful EMS procedures. This has the potential to minimize errors caused by operator inexperience and mitigate the risks associated with excessive bone removal.

Development of transporter training simulator based on virtual reality and vehicle dynamics model

A transporter is a means of transportation that is widely used in heavy industries to move heavy loads called blocks. Because the transporter has a more complex operating system compared to the regular car, it takes a lot of time to become familiar with its operation. However, it is not easy to find a proper place and a transporter for training operators. As a result, the number of accidents caused by the operator's inexperience, such as block drops or collisions, is increasing every year. Therefore, in this study, a transporter training simulator based on virtual reality is developed to allow transporter operators to be trained anytime, anywhere without considering actual transporter and a special training place. This training simulator is composed of five modules. The first module is models of the transporter and the shipyard to be displayed in virtual reality. The second is implementation of the transporter operations such as lifting, lowering, and moving wheels. The third is vehicle dynamics model to implement realistic movement of the transporter. The fourth is the network function to simulate collaboration among workers. The fifth is the scenario module to simulate work situations that are similar to actual ones. By using the developed simulator, a scenario where the signalman and the operator collaborate to transport a block is successfully conducted.

Frequency and etiological denominators of alveolar osteitis at Northern Province of Kingdom of Saudi Arabia-An observational study.

Alveolar osteitis is a painful complication that often arises after tooth extraction, presenting a significant clinical challenge. It is imperative to gain a comprehensive understanding of both its occurrence and the contributing factors to enhance the quality of dental care. The aim of this study was to assess the frequency and prevalence of alveolar osteitis among patients and compare these variables based on demographic characteristics (age and sex), the number of teeth extractions, operator experience, health status, and smoking habits in the target population. This cross-sectional observational study was conducted from May 2019 to April 2020. It included all patients above 16 years of age, of both genders, who underwent permanent tooth extraction for various reasons. Patient demographics, smoking habits, health status, operating dental surgeon's clinical experience, extraction technique, and the number of teeth extracted were recorded. Statistical analysis was performed using SPSS version 25. Chi-square test and regression analysis were used to assess differences between age, sex, smoking habit, dentist category, and the number of teeth extractions in relation to alveolar osteitis. A total of 679 permanent tooth extractions were performed in 438 patients. Alveolar osteitis was observed in 107 cases (15.7%) following tooth extractions. Among these, 36 cases (33.6%) occurred in single tooth extraction cases, while 71 cases (66.4%) were present in patients with multiple extractions. Moreover, 67 cases (62.6%) of alveolar osteitis were found in cigarette smokers. In addition, 61 cases (57%) of dry sockets were reported after tooth extractions performed by dental interns, while 46 cases (43.0%) were noted in extractions performed by experienced dental surgeons and specialists. The study found a 15.7% incidence of alveolar osteitis in tooth extraction patients in the Al-Jouf region. Alveolar osteitis was more prevalent in males and the age group of 56-77 years. Multiple tooth extractions were associated with higher alveolar osteitis incidence, while operator inexperience increased post-extraction complication risks. In addition, a promising novel protocol and risk assessment scoring system have been devised which require further validation and future research.

A Controlled Experiment to Test the Efficacy of Ground-Penetrating Radar in the Search for Clandestine Burials in Poland

The international workshop ‘Forensic Search and Recovery of Clandestine Graves’ took place over two days in 2021 in Wroclaw, Poland. The goal of the workshop was to improve search methods and techniques related to the examination of clandestine burial sites. Geophysical methods were used by an international team of multi-disciplinary specialists to detect simulated burial sites. The training focused on testing methods, including Ground-Penetrating Radar (GPR), to verify the effectiveness of the methods in the search for two features representing clandestine burials. The forensic community in Central European countries, including Poland, has been slow to adopt these technologies due to controversial results. While geophysical research is successfully carried out in archaeological research and forensic contexts internationally, its application in the activities of the prosecutor’s office and the police in Poland has been relatively unsuccessful. This has resulted in several controversies related primarily to the erroneous expectations of how the methods are successfully applied. This may be the result of operator inexperience in applying these methods to the search for clandestine burials. This training paired an experienced GPR operator with law enforcement teams and archaeologists, leading to the successful discovery of simulated burials using GPR.

Abstract 231: Patient, Operator, And Procedural Characteristics Of Guidewire Retention As A Complication Of Vascular Catheter Insertion

Introduction: Guidewire retention after intravascular catheter insertion is considered a “never event.” Prior reports attribute this complication to various characteristics including uncooperative patients, operator inexperience, off-hour or emergent insertion, and underutilization of ultrasound guidance. In this descriptive analysis of consecutive events, we assessed the frequency of patient, operator, and procedural factors in guidewire retention. Methods: All consecutive incidents of guidewire retention across 10 hospitals within the Cleveland Clinic Health System in Ohio from August 2007 to October 2015 were prospectively identified and retrospectively analyzed. Data were manually obtained from the electronic medical records and reviewed for potential contributing factors for guidewire retention including patient, operator, and procedural characteristics. Results: A total of 24 guidewire retention events were identified. Overall, the median age was 74 years, 58% were males, and the median body mass index was 26.5 kg/m 2 . A total of 12 (50%) individuals were sedated during the procedure. Most incidents (10 [42%]) occurred in internal jugular venous access sites. The majority of cases (13 [54%]) were performed or supervised by an attending. Among all cases, 3 (12%) were performed by first-year trainees, 7 (29%) by residents, 3 (12%) by fellows, and 4 (17%) by certified nurse practitioners. Overall, 16 (67%) events occurred during regular working hours (8AM - 5PM). In total, 22 (92%) guidewires were inserted non-emergently, with 2 (8%) during a cardiac arrest. Ultrasound guidance was used in all but 1 case. Conclusion: Guidewire retention can occur even in the presence of optimal patient, operator, and procedural circumstances, highlighting the need for constant awareness of this risk. Efforts to eliminate this important complication will require attention to issues surrounding the technical performance of the procedure.

Surgery appears to outperform endovascular therapy for popliteal artery aneurysms; however, the real answer as to which treatment strategy works best and for whom remains elusive

Surgery appears to outperform endovascular therapy for popliteal artery aneurysms; however, the real answer as to which treatment strategy works best and for whom remains elusive

Factors that Influence the Clinical Longevity of Ceramic Unit Restoration: A Scoping Review

Statement of Problem: Ceramic restorations can be essential in dental rehabilitation aesthetic and functional, but its longevity and treatment plan need to be good settled down. Different material options, manufacturing techniques and protocols are available. It is important to map the literature to know the state of the art about of clinical failures related to these fixed prostheses.&#x0D; Purpose: Evaluate the rate of survival of single restorations (crowns and ceramic veneers) as well as identify the types of clinical complications reported.&#x0D; Material and methods: A scoping review was conducted from the MEDLINE/Pubmed, Embase, Scopus, Web of Science and Cochrane Library. A search of all published literature until June 2021 was based on the following keywords: ('dental crown' OR 'ceramic veneer' OR 'porcelain veneer' OR 'dental veneer' OR 'dental porcelain') AND ('survival rate' OR 'ceramic restoration failure' OR 'prosthesis complication' OR complication).&#x0D; Results: The most reported biological complications were need for treatment endodontic and detachment. The complications and technical failures involved, mainly, fractures and cracks in ceramics. There were also cases of pigmentation marginal.&#x0D; Conclusion: The survival rate of single ceramic restorations is high. The main factors influencing restoration failures are bruxism, operator inexperience and inadequate cementation.

PFP-LHCINCA: Pyramidal Fixed-Size Patch-Based Feature Extraction and Chi-Square Iterative Neighborhood Component Analysis for Automated Fetal Sex Classification on Ultrasound Images.

Objectives Fetal sex determination with ultrasound (US) examination is indicated in pregnancies at risk of X-linked genetic disorders or ambiguous genitalia. However, misdiagnoses often arise due to operator inexperience and technical difficulties while acquiring diagnostic images. We aimed to develop an efficient automated US-based fetal sex classification model that can facilitate efficient screening and reduce misclassification. Methods We have developed a novel feature engineering model termed PFP-LHCINCA that employs pyramidal fixed-size patch generation with average pooling-based image decomposition, handcrafted feature extraction based on local phase quantization (LPQ), and histogram of oriented gradients (HOG) to extract directional and textural features and used Chi-square iterative neighborhood component analysis feature selection (CINCA), which iteratively selects the most informative feature vector for each image that minimizes calculated feature parameter-derived k-nearest neighbor-based misclassification rates. The model was trained and tested on a sizeable expert-labeled dataset comprising 339 males' and 332 females' fetal US images. One transverse fetal US image per subject zoomed to the genital area and standardized to 256 × 256 size was used for analysis. Fetal sex was annotated by experts on US images and confirmed postnatally. Results Standard model performance metrics were compared using five shallow classifiers—k-nearest neighbor (kNN), decision tree, naïve Bayes, linear discriminant, and support vector machine (SVM)—with the hyperparameters tuned using a Bayesian optimizer. The PFP-LHCINCA model achieved a sex classification accuracy of ≥88% with all five classifiers and the best accuracy rates (>98%) with kNN and SVM classifiers. Conclusions US-based fetal sex classification is feasible and accurate using the presented PFP-LHCINCA model. The salutary results support its clinical use for fetal US image screening for sex classification. The model architecture can be modified into deep learning models for training larger datasets.

Endodontic instruments fracture in root canal: Integrative review

Introduction: Endodontic instruments fracture is related to several factors from internal dental anatomy and type, to operator inability and inexperience. Objective: To review case reports related to fracture of endodontic instruments inside the root canal. Methodology: A literature review was carried out using papers available in the PubMed and Lilacs databases. Only case reports were included, with no restriction on language and publication year Results: It was analyzed eight papers with 11 instrument fracture cases, with the highest prevalence (45.5%) of rotary instruments fracture, occurring mainly in middle-cervical and middle-apical root canals thirds. In 90.9% of cases, techniques used for removal showed successful results and in only one case (9.1%), the technique was unsuccessful and the instrument was kept inside the root canal. Final considerations: Endodontic instruments fracture is a complication can directly affect prognosis and endodontic treatment success. Several techniques and devices can be used to remove fractured fragments inside root canals, however, there is no specific protocol for their removal. Keywords: accidents; endodontics; fracture; dental instruments; prognosis.

Ultrasonography-Guided Core Needle Biopsy Diagnostic Value in Breast Lump Assessment: An Experience From the Middle East

Objective: Breast cancer is a leading cause of mortality in industrialized and developing countries. Mammography and a core needle biopsy are among the detection methods that are used to diagnose and confirm tumor subtypes. Methods: A retrospective, noninterventional observational study was conducted in a tertiary center between January 2009 and December 2014. A total of 265 patients underwent ultrasonography (US)–guided core needle biopsy (CNB). A cohort of 147 patients met the inclusion criteria and data were subsequently extracted from their medical records. Results: From this cohort, US-CNB detected malignant lesions in 109 patients, with a total sensitivity and specificity for malignancy at 96.33% and 75.10%, respectively. The most frequent malignant tumor diagnosed with US-CNB was invasive ductal carcinoma. The most common benign masses detected were 38 (32.1%) fibroadenomas and fat necrosis. The positive and negative predictive values for US-CNB were 92.4% and 87.5%, respectively. Conclusion: The findings would suggest that the use of US-CNB could play a major role in the identification and management of the breast lesions. It could also redeem any biopsy errors or operator inexperience. Sensitivity and specificity in detecting tumors, malignant or benign, using US-CNB could aid in efforts to provide an appropriate medical management plan.

S1212 Luminal Complications Attributed to Intra-Gastric Balloon Placement: A Systematic Review

INTRODUCTION: Intra-gastric balloons (IGB) pose an effective, and generally well tolerated non-surgical modality for weight loss. Major complications from IGB placement are rare but could carry significant morbidity. In this comprehensive review, we aim to review the frequency of luminal complications of IGBs, outline the clinical features, and outcomes of these patients. METHODS: A comprehensive review of Ovid MEDLINE and EMBASE databases until April 7th, 2020 was conducted. Studies of any design were included if they reported on luminal complications following IGB placement including esophagitis, gastritis, ulcers, erosions, perforation, or luminal obstruction. Two independent reviewers selected and appraised studies using the Newcastle Ottawa Scale (NOS), Cochrane tool and the Murad tool. RESULTS: The most commonly encountered complication in population studies was gastritis, gastric erosions and gastric ulceration (1.4%) followed by esophagitis (0.93%). Gastric Outlet Obstruction (GOO), gastric perforation, bowel obstruction and esophageal perforation are rare complications with <1% prevalence each, however carry significant morbidity. A total of 75 patients developing luminal complications were identified in case reports/series. Of the complications encountered, gastric perforation appears to carry a high mortality (31.3%). CONCLUSION: Life-threatening complications of IGB placement are rare and hence IGBs remain safe devices for weight loss treatment. Frequently complications occured in the setting of operator inexperience, or patient non-compliance to balloon removal times and post-placement protocols. Being cognizant of these complications is necessary in implementing IGBs as adjunct weight loss modalities.Table 1

The incidence and predictors of hypoxaemia during induction of general anaesthesia for caesarean delivery in two South African hospitals : a prospective, observational, dual-centre study

Background: Caesarean delivery is the most commonly performed surgery in Africa. Morbidity and mortality linked to tracheal intubation represent a growing national health concern, yet there is minimal data relating to airway management in this group of patients. Methods: We conducted a prospective, observational, dual-centre cohort study with the aim of quantifying the incidence of hypoxaemia (SpO2 &lt; 90%) at induction of general anaesthesia for caesarean delivery. We further aimed to explore body mass index, operator inexperience, predicted difficult airway, Cormack-Lehane grading and the absence of planned mask ventilation as predictors of hypoxaemia in our population. Airway complications were also quantified. Results: We included 363 patients in our study. The incidence of hypoxaemia was 61/363 (16.8%, 95% CI 13.29-21.02). High body mass index (&gt; 30 kg/m2) and Cormack-Lehane grade (4) were predictive of hypoxaemia during induction. The failed intubation rate was 1.4% (95% CI 0.57–3.28) and the regurgitation rate was 0.8% (95% CI 0.27–2.54). There were no pulmonary aspirations and no surgical airways were required. Conclusion: The incidence of hypoxaemia during general anaesthesia for caesarean delivery is high. Future studies should examine methods to reduce the incidence of hypoxaemia, either through improved training or via specific interventions in this high-risk group.

Contact-force radiofrequency ablation of non-paroxysmal atrial fibrillation: improved outcomes with increased experience.

Clinical trials have failed to reliably show improved outcomes with utilization of contact-force sensing (CFS) radiofrequency (RF) ablation catheters. It is unknown whether the unfavorable outcomes observed in these trials are attributable to inexperience with CFS technology. To compare catheter ablation outcomes of stepwise linear ablation with versus without CFS technology and to assess the impact of operator experience with CFS technology on procedural outcomes. Clinical outcomes were evaluated in 228 consecutive NPAF patients undergoing first-time left atrial ablation using a stepwise linear approach. Arrhythmia recurrence was assessed using 2-week event monitors at 3-month intervals following index ablation. A total of 228 patients were included in our study. There was no statistically significant difference in risk of recurrent atrial arrhythmias at 12 and 24months between CFS and non-CFS patients (p = 0.5 and p = 0.169). The time to recurrence of atrial arrhythmias at 24months in the second half of CFS patients was significantly lower when compared to both the first half of CFS patients (p = 0.002) and non-CFS patients (p = 0.005). While there was no difference in overall outcomes between CFS and non-CFS ablation using a stepwise linear approach in patients with NPAF, procedural efficacy of the second half of CFS patients was significantly improved compared to both the first half of CFS patients and all non-CFS patients. Lack of benefit seen in clinical trials using CFS technology may be related to operator inexperience with CFS ablation catheters at the time of the trials.

Beyond the Learning Curve: Comparison of Microscopic and Endoscopic Incidences of Internal Carotid Injury in a Series of Highly Experienced Operators

As the endoscopic endonasal approach (EEA) has gained popularity as an alternative to microsurgery (MS) for transsphenoidal resection (TSR), numerous studies have attempted to assess the differential risk of internal carotid artery (ICA) injury between the techniques, yet results have been equivocal and contradictory. The aim of this study was to evaluate ICA injury in MS versus EEA among highly experienced neurosurgeons. We performed a systematic literature review of publications from 2002-2017 reporting ICA injury outcomes in ≥250 cases using MS or EEA. Seventeen series reporting 11,149 patients were included: 3 MS series, 13 EEA series, and 1 series with adequate samples for each. ICA injury incidences were 0.0%-1.6% in cohorts of 275-3000. MS series documented 5 ICA injuries in 2672 operations, for an overall incidence of 0.2% (range, 0.0%-0.4%), and EEA series reported 30 ICA injuries in 8477 operations, for a 0.4% injury rate (range, 0.0%-1.6%); the difference was nonsignificant (P= 0.25). Increased operative experience was associated with decreased incidence of ICA injury, a finding preserved in the overall study cohort and within discretely examined MS and EEA subgroups (overall r2= 0.08, MS r2= 0.23, EEA r2= 0.07). ICA injury is the most serious complication of TSR of pituitary neoplasms. Operator inexperience may be a more important risk factor than choice of surgical technique, given the comparably low rates of injury obtained by highly experienced surgeons independent of technique. This emphasizes the need for consolidated care in pituitary centers of excellence, improvement of high-fidelity simulators, and skull base mentorship between senior and junior staff.

Ultrasound of the midfoot ligaments, syndesmosis and bands of the deltoid

This presentation will predominantly bring together methods for scanning all regions of the ankle and midfoot to result in a thorough front-line approach to ligament injury in the acute setting. While alternative diagnostic techniques exist, each offering varying degrees of accuracy, expense and time, it is posited that ultrasound is an accurate, cost-effective, and efficient modality for front-line assessment in acute and subacute ankle sprains. Ultrasound examination is often confined to the lateral ligament complex due to operator inexperience or the ingrained perception that its use in other regions of the ankle is limited. However, if the scope of an ultrasound examination is not extended to include the midfoot, syndesmosis and medial ankle, more time-critical injuries may be missed leading to poor patient management and recovery. The following demonstrations will be given in support of this posit: 1. Correct probe positioning to find important midfoot ligaments 2.Correct dynamic stress-ultrasound for detection of tibiofibular diastasis in the setting of AITFL ligament disruption (high ankle sprain) 3. Correct patient positioning to optimally visualise the components of the medial ankle deltoid ligament. It will be seen that such ultrasound techniques can be used to obtain comparative views; allow for accurate appraisals of the tibiofibular syndesmosis, midfoot and deltoid ligaments (along with routine lateral ligament complex assessment). Dynamic positioning of the ankle or stress-ultrasound during assessment can assist with triage and ensure that best patient management is provided.

Influence of multiple stents on periprocedural stroke after carotid artery stenting in the Carotid Revascularization Endarterectomy versus Stent Trial (CREST)

BackgroundIn the Carotid Revascularization Endarterectomy versus Stent Trial (CREST), carotid artery atherosclerotic lesion length and nature of the lesions were important factors that predicted the observed difference in stroke rates between carotid endarterectomy and carotid artery stenting (CAS). Additional patient-related factors influencing CAS outcomes in CREST included age and symptomatic status. The importance of the operator's proficiency and its influence on periprocedural complications have not been well defined. We evaluated data from CREST to determine the impact of use of multiple stents, which we speculate may be related to technical proficiency. MethodsCREST includes CAS performed for symptomatic ≥50% carotid stenosis and asymptomatic ≥70% stenosis. Both symptomatic and asymptomatic patients were enrolled in the trial and in the lead-in registry. Data from patients enrolled in the CREST registry and randomized trial from 2000 to 2008 were reviewed for patient- and lesion-related characteristics along with number of stents deployed. The occurrence of 30-day stroke and demographic and clinical features were recorded. Odds ratios for 30-day stroke associated with the use of multiple stents were calculated in univariate analysis and on multivariable analysis after adjustment for demographics (age, sex, symptomatic status), lesion characteristics (length, ulceration, eccentric, percentage stenosis), and risk factors (diabetes, hypertension, dyslipidemia, and smoking). ResultsThe registry (n = 1531) and trial (n = 1121) enrolled 2652 patients undergoing CAS. The mean age was 69 years; 36% were women, and 38% were symptomatic. The mean diameter stenosis was 78%, and the mean lesion length was 18 mm (±standard deviation, 8 mm). Risk factors included hypertension (85%), diabetes (32%), dyslipidemia (84%), and smoking (23%). All patients received Acculink stents (Abbott Vascular, Abbott Park, Ill) that were 20, 30, or 40 mm in length (straight or tapered) and Accunet (Abbot Vascular) embolic protection when possible. Most patients received one stent (n = 2545), whereas 98 patients received two stents and 9 patients received three stents (P < .001) to treat the lesion. Patients receiving more than one stent were older (P = .01) but did not differ in other demographic or risk factors. Strokes occurred in 118 (4.5%) of all CAS procedures, in 102 (4%) with the use of one stent, and in 16 (15%) with the use of two or three stents. After adjustment for demographics, lesion characteristics, and risk factors, the use of more than one stent resulted in 2.90 odds (95% confidence interval, 1.49-5.64) for a stroke. ConclusionsAlthough we know that lesion characteristics (length, ulceration) play an important role in CAS outcomes, in this early experience with carotid stenting, a significant and independent relationship existed between the number of stents used and procedural risk of CAS. We postulate that this was an indicator of the operator's inexperience with the procedure.