Low-cost simulation model for ultrasound-guided punch biopsy and puncture: Construction manual and photo examples

PURPOSE

Ultrasound-guided puncture and punch biopsy pose a particular challenge in ultrasound examination training. These techniques should be learned and performed several times using a simulation model that is as realistic as possible before being applied to patients. While the use of agar-agar-based models is extensively documented in the literature, there is a discernible gap in publications specifically addressing their use in punch biopsy and puncture. The aim was to develop a cost-effective model for the simulation of ultrasound-guided interventions.

MATERIALS AND METHODS

The developed simulation model is based on the vegetable gelatine agar-agar. The agar-agar powder is boiled in water and colored. Various objects are added to the mass. Blueberries, olives, tomatoes, and cornichons imitate solid structures. Liquid-filled balloons are used to simulate cystic structures. Adding stones can make the exercises more difficult due to hyperechoic reflexes with distal shadowing.

RESULTS

With the model, ultrasound-guided puncture and punch biopsies could be successfully simulated, and ultrasound images can be generated for this purpose. The cost of a single model is about 2 euros. Production takes less than 2 hours, including cooling. The pure processing time is 30 minutes. The durability of the models is limited by mold, which occurs after 5 days when stored at room temperature and after 5 weeks in the refrigerator.

CONCLUSION

It was shown that it is possible to produce an inexpensive agar-agar-based ultrasound model in a short time and with easily available ingredients to learn ultrasound-guided puncture and punch biopsies.

Visualization of bone formation in sheep's middle ear by using fluorochrome sequential labelling (FSL)

One factor for the lacking integration of the middle ear stapes footplate prosthesis or the missing healing of stapes footplate fractures could be the known osteogenic inactivity. In contrast, it was recently demonstrated that titanium prostheses with an applied collagen matrix and immobilised growth factors stimulate osteoblastic activation and differentiation on the stapes footplate. Regarding those findings, the aim of this study was to evaluate the potential of bone regeneration including bone remodeling in the middle ear. Ten one-year-old female merino sheep underwent a middle ear surgery without implantation of middle ear prostheses or any other component for activating bone formation. Post-operatively, four fluorochromes (tetracycline, alizarin complexion, calcein green and xylenol orange) were administered by subcutaneous injection at different time points after surgery (1 day: tetracycline, 7 days: alizarin, 14 days: calcein, 28 days: xylenol). After 12 weeks, the temporal bones including the lateral skull base were extracted and histologically analyzed. Fluorescence microscopy analysis of the entire stapes with the oval niche, but in particular stapes footplate and the Crura stapedis revealed evidence of new bone formation. Calcein was detected in all and xylenol in 60% of the animals. In contrast, tetracycline and alizarin could only be verified in two animals. The authors were able to demonstrate the osseoregenerative potential of the middle ear, in particular of the stapes footplate, using fluorescence sequence labelling.

The value of subcutaneous xenografts for individualised radiotherapy in HNSCC: Robust gene signature correlates with radiotherapy outcome in patients and xenografts

PURPOSE

To assess the robustness of prognostic biomarkers and molecular tumour subtypes developed for patients with head and neck squamous cell carcinoma (HNSCC) on cell-line derived HNSCC xenograft models, and to develop a novel biomarker signature by combining xenograft and patient datasets.

MATERIALS AND METHODS

Mice bearing xenografts (n = 59) of ten HNSCC cell lines and a retrospective, multicentre patient cohort (n = 242) of the German Cancer Consortium-Radiation Oncology Group (DKTK-ROG) were included. All patients received postoperative radiochemotherapy (PORT-C). Gene expression analysis was conducted using GeneChip Human Transcriptome Arrays. Xenografts were stratified based on their molecular subtypes and previously established gene classifiers. The dose to control 50 % of tumours (TCD50) was compared between these groups. Using differential gene expression analyses combining xenograft and patient data, a gene signature was developed to define risk groups for the primary endpoint loco-regional control (LRC).

RESULTS

Tumours of mesenchymal subtype were characterized by a higher TCD50 (xenografts, p < 0.001) and lower LRC (patients, p < 0.001) compared to the other subtypes. Similar to previously published patient data, hypoxia- and radioresistance-related gene signatures were associated with high TCD50 values. A 2-gene signature (FN1, SERPINE1) was developed that was prognostic for TCD50 (xenografts, p < 0.001) and for patient outcome in independent validation (LRC: p = 0.007).

CONCLUSION

Genetic prognosticators of outcome for patients after PORT-C and subcutaneous xenografts after primary clinically relevant irradiation show similarity. The identified robust 2-gene signature may help to guide patient stratification, after prospective validation. Thus, xenografts remain a valuable resource for translational research towards the development of individualized radiotherapy.

Adjusting the RAPID score with 2 additional variables significantly increases its predictive value in patients with empyema

Pleural empyema is a serious condition leading to a significant burden on health care systems due to protracted hospitalisations. Treatment ranges from non-surgical interventions such as antibiotic therapy and chest tube placement to thoracoscopic or open surgery. Various risk factors which impact outcomes have been investigated. The RAPID (renal, age, purulence, infection source, and dietary factors) score is a clinical risk score which identifies patients at risk of death and may be used to formulate individual treatment strategies accordingly. All patients undergoing surgical interventions for empyema at a major tertiary medical centre in Germany from 2017 to 2020 were analysed. The aim was to identify perioperative risk factors which significantly impact treatment outcomes but are currently not included in the RAPID score. 245 patients with pleural empyema surgically treated at the Department of General, Visceral and Thoracic Surgery at the University Medical Centre, Hamburg, Germany (admitted from January 2017 to April 2020) were retrospectively analysed. All patients which received either minimally invasive or open thoracic surgery were included. Epidemiological as well as perioperative data was analysed to identify risk factors which impact long-term overall outcomes. 90-day mortality rate was the primary endpoint. The mean age was 59.4 years with a bimodal distribution. There was a male predominance across the cohort (71.4% compared to 28.6%), with no significant differences across ages below or above 60 years. 53 (21.6%) patients died within the first 90 days. Diabetes type 1 and 2, renal replacement therapy, immunosuppression, postoperative bleeding, intraoperative transfusion as well as microbiologically confirmed bacterial invasion of the pleura all led to higher mortality rates. Higher RAPID scores accurately predicted higher 90-day mortality rates. Modifying the RAPID score by adding the comorbidities diabetes and renal replacement therapy significantly increased the predictive value of the score. We demonstrated various perioperative and patient related risk-factors not included in the RAPID score which negatively impact postoperative outcome in patients receiving surgical treatment for pleural empyema. These should be taken into consideration when deciding on the best course of treatment. If confirmed in a prospective study including non-surgical patients with a significantly larger cohort, it may be worth considering expanding the RAPID score to include these.

Assessment of gene expressions from squamous cell carcinoma of the head and neck to predict radiochemotherapy-related xerostomia and dysphagia

PURPOSE

We tested the hypothesis that gene expressions from biopsies of locally advanced head and neck squamous cell carcinoma (HNSCC) patients can supplement dose-volume parameters to predict dysphagia and xerostomia following primary radiochemotherapy (RCTx).

MATERIAL AND METHODS

A panel of 178 genes previously related to radiochemosensitivity of HNSCC was considered for nanoString analysis based on tumour biopsies of 90 patients with locally advanced HNSCC treated by primary RCTx. Dose-volume parameters were extracted from the parotid, submandibular glands, oral cavity, larynx, buccal mucosa, and lips. Normal tissue complication probability (NTCP) models were developed for acute, late, and for the improvement of xerostomia grade ≥2 and dysphagia grade ≥3 using a cross-validation-based least absolute shrinkage and selection operator (LASSO) approach combined with stepwise logistic regression for feature selection. The final signatures were included in a logistic regression model with optimism correction. Performance was assessed by the area under the receiver operating characteristic curve (AUC).

RESULTS

NTCP models for acute and late xerostomia and the improvement of dysphagia resulted in optimism-corrected AUC values of 0.84, 0.76, and 0.70, respectively. The minimum dose to the contralateral parotid was selected for both acute and late xerostomia and the minimum dose to the larynx was selected for dysphagia improvement. For the xerostomia endpoints, the following gene expressions were selected: RPA2 (cellular response to DNA damage), TCF3 (salivary gland cells development), GBE1 (glycogen storage and regulation), and MAPK3 (regulation of cellular processes). No gene expression features were selected for the prediction of dysphagia.

CONCLUSION

This hypothesis-generating study showed the potential of improving NTCP models using gene expression data for HNSCC patients. The presented models require independent validation before potential application in clinical practice.

[Vestibular schwannomas - baseline and progress diagnostics]

Vestibular (vestibulocochlear) schwannomas are rare, benign schwannomas of the cerebellopontine angle, the internal auditory canal, or the inner ear. They can occur with or without clinical symptoms. The most common symptoms are unilateral or side-differentiated hearing loss with or without tinnitus and balance disorders. Initial symptomatology is nonspecific in the basic functional diagnosis, raising the question of when a hearing or balance disorder should be thought of as a differential diagnosis of vestibular schwannoma and what diagnostic pathway is appropriate. This concerns not only the confirmation of the diagnosis and the recording of all dysfunctions of the involved cranial nerves in the initial basic diagnostics, but also the procedure in the course and follow-up diagnostics - especially in patients who are subject to an observation strategy. Today, imaging alone is no longer sufficient for differentiated and individualized patient counseling. Due to the increasing detection of smaller tumors on MRI and the growing proportion of nearly asymptomatic patients, a shift in thinking from pure imaging monitoring to a detailed analysis of auditory and vestibular function is timely. In this educational article, diagnostic pathways for a sufficient patient consultation will be compiled. Ultimately, functional examination techniques from follow-up and progression diagnostics will also be included.

[The situation of education in ENT-residency-training in Germany]

Hintergrund

Als Ansatzpunkt zur Entwicklung konkreter Optimierungsvorschläge für das HNO-ärztliche Weiterbildungssystem wurde zunächst die Ausbildungssituation an deutschen HNO-Kliniken analysiert, um existierende Schwachstellen der Weiterbildung identifizieren zu können.

Methodik

HNO-Weiterbildungsassistenten an deutschen HNO-Kliniken wurden eingeladen, an einer Online-Befragung teilzunehmen. Der Fragebogen bestand dabei aus 78 Einzelfragen.

Ergebnisse

An der Umfrage nahmen 223 Weiterbildungsassistenten der HNO-Heilkunde teil. Defizite der Ausbildung wie ein fehlendes regelmäßiges Feedback zwischen Weiterbildungsberechtigten und Weiterbildungsassistenten/-innen, eine nur mittelmäßig bewertete Vermittlung von Fachkompetenz sowie eine in den Freitextkommentaren genannte „Willkür“ der Weiterbildungsbeauftragten hinsichtlich der Gestaltung des Weiterbildungsverlaufs sowie Zeit- und Personalmangel treten in den Fokus unserer Auswertung. Einige der verbindlich aufgeführten Empfehlungen der Weiterbildungsordnung wie die Festlegung von konkreten Weiterbildungszielen im Rahmen eines regelmäßigen Gesprächs oder der Einsatz eines Log-Buchs werden bislang nur vereinzelt umgesetzt. Forderungen zum Ausbau von externen Fortbildungsmöglichkeiten (Hospitation/Rotation) und einer externen objektiven Überprüfung der klinikinternen Durchführung der Weiterbildung im Sinne einer Qualitätssicherung beispielsweise durch Fachvertreter der Deutschen Gesellschaft für HNO-Heilkunde, Kopf- und Halschirurgie (DGHNOKHC) werden diskutiert.

Schlussfolgerung

Die Umsetzung einer strukturierten und standardisierten Weiterbildung in Deutschland, welche im Sinne einer freiwilligen Eigeninitiative auch durch die DGHNOKHC in ihrer Umsetzung überprüft wird, kann eine Basis für eine effektivere verbindliche Weiterbildung schaffen.

Zusatzmaterial online

Die Online-Version dieses Beitrags (10.1007/s00106-020-00838-9) enthält eine Tabelle, die Ergebnisse einer Fragenauswahl gegliedert nach Themenkomplexen darstellt. Beitrag und Zusatzmaterial stehen Ihnen auf www.springermedizin.de zur Verfügung. Bitte geben Sie dort den Beitragstitel in die Suche ein, das Zusatzmaterial finden Sie beim Beitrag unter „Ergänzende Inhalte“.

Erratum zu: Die Weiterbildungssituation in der HNO-Heilkunde in Deutschland

Ein Erratum zu dieser Publikation wurde veröffentlicht: 10.1007/s00106-020-00838-9

[From reconstruction to function : Hands-on training in tympanoplasty using real-time feedback]

Hintergrund

In der Mittelohrchirurgie bedarf es ausgezeichneter feinmotorischer Fertigkeiten. Aufgrund des hohen Komplikationspotenzials im Mittelohr ist die Ausbildung dieser Fertigkeiten am Modell anzustreben.

Fragestellung

Wie gut ist die Ausbildungsmöglichkeit an geeigneten Modellen? Können die am Modell erlernten Fertigkeiten in die intraoperative Situation übertragen werden? Beeinflusst das Modell und die Ausbildung daran die zukünftige Ohrchirurgie?

Material und Methode

Vorliegende Publikationen und eigene Erfahrungen am Dresdener Tympanoplastikmodell (DTM) wurden analysiert und diskutiert.

Ergebnisse

Obwohl die Mittelohrchirurgie hohe Anforderungen an den Ausführenden stellt und am Sinnesorgan Ohr schwerwiegende Komplikationen drohen, gibt es bisher nur wenige Trainingsmöglichkeiten dafür. Das DTM ist ein validiertes Übungsmodell, das diese Lücke schließen kann. Durch eine Real-Time-Feedback-Variante des Modells kann auch das Verständnis für Rekonstruktionsqualität und intraoperative akustische Noxen verbessert werden. Die Übertragung des Real-Time-Feedback-Gedankens in die reale Mittelohrchirurgie kann die Rekonstruktionsqualität zukünftig verbessern.

Schlussfolgerungen

Das Training an geeigneten Modellen ist speziell beim Erlernen der Mittelohrchirurgie anzustreben. Mit dem Real-Time-Feedback kann beim Lernen und Operieren eine weitere Sinneswahrnehmung in die eigene und fremde Qualitätskontrolle der Tympanoplastik sehr wirksam einbezogen werden.

Interdisciplinary Comparison of Endoscopic Laser-Assisted Diverticulotomy vs. Transcervical Myotomy as a Treatment for Zenker's Diverticulum

BACKGROUND

Currently, there are different competing techniques for the treatment of Zenker's diverticulum (ZD). To improve patient selection, we compared endoscopic laser-assisted diverticulotomy (ELAD) with transcervical myotomy (TCM) with regard to possible risk factors for treatment failure.

METHODS

Data of ZD patients (n = 104) treated between 2004 and 2016 with either TCM (38%) or ELAD (62%) were analyzed retrospectively. Univariate and multivariate analyses were performed.

RESULTS

TCM is associated with a higher morbidity (27.8% vs. 10.2%; p = 0.095) but lower recurrence rate (7.3% vs. 19.3%; p = 0.095). Preoperative reflux disease (OR 8.755; p = 0.021) was identified as an independent risk factor for complications.

CONCLUSIONS

Although short-term outcome and symptom relief are similar, TCM tends to have a higher complication rate but better long-term results. Preoperative reflux disease is an independent risk factor for postoperative complications.

Endoscopic optical coherence tomography with wide field-of-view for the morphological and functional assessment of the human tympanic membrane

An endoscopic optical coherence tomography (OCT) system with a wide field-of-view of 8 mm is presented, which combines the image capability of endoscopic imaging at the middle ear with the advantages of functional OCT imaging, allowing a morphological and functional assessment of the human tympanic membrane. The endoscopic tube has a diameter of 3.5 mm and contains gradient-index optics for simultaneous forward-viewing OCT and video endoscopy. The endoscope allows the three-dimensional visualization of nearly the entire tympanic membrane. In addition, the oscillation of the tympanic membrane is measured spatially resolved and in the frequency range between 500 Hz and 5 kHz with 125 Hz resolution, which is realized by phase-resolved Doppler OCT imaging during acoustical excitation with chirp signals. The applicability of the OCT system is demonstrated in vivo. Due to the fast image acquisition, structural and functional measurements are only slightly affected by motion artifacts.

Imaging of the human tympanic membrane by endoscopic optical coherence tomography

Endoscopic optical coherence tomography is a non-invasive and contactless imaging technique based on white light interferometry. It enables high-resolution three-dimensional imaging of scattering tissue up to a depth of about 2 mm. In addition, Doppler-OCT can detect sub-resolution movements. These features can be used to examine the tympanic membrane, the surrounding tissue and nearby areas of the tympanic cavity. For this purpose, we present an endoscopic OCT system, which provides access to the tympanic membrane. The design of the endoscope is based on a gradientindex (GRIN) lens system. This allows a broad field of view and a large working distance. An additional VIS beam path allows visual imaging and orientation inside the auditory canal. Therefore, illumination fibers are attached a round the GRIN-system. The resulting endoscope has a length of 55 mm and a diameter of 3.5 mm. By attaching an earphone and a probe microphone, the oscillation of the tympanic membrane can be measured under acoustic stimulation. With the endoscopic OCT system, we provide an examination tool for the diagnosis of a broad number of diseases like conductive hearing loss.

Functional and morphological imaging of the human tympanic membrane with endoscopic optical coherence tomography

In this ex vivo feasibility study, endoscopic structural and functional optical coherence tomography (OCT) imaging with a field of view of 8 mm is presented allowing the inspection of nearly the entire tympanic membrane through the ear canal. The endoscope utilizes a gradient index optics for simultaneous OCT and video endoscopy. Additionally, Doppler-OCT allows the measurement of the tympanic membrane oscillation. Due to the fast image acquisition, only minor motion artifacts have been observed, which don’t affect the image quality. In conclusion, endoscopic OCT is considered as a promising tool for the comprehensive examination of the human middle ear.

Patency of paediatric endotracheal tubes for airway instrumentation

BACKGROUND

Airway exchange catheters (AEC) and fiberoptic bronchoscopes (FOB) for tracheal intubation are selected so that there is only a minimal gap between their outer and inner diameter of endotracheal tube (ETT) to minimize the risk of impingement during airway instrumentation. This study aimed to test the ease of passage of FOBs and AECs through paediatric ETT of different sizes and from different manufacturers when using current recommendations for dimensional equipment compatibility taken from text books and manufacturers information.

METHODS

Twelve different brands of cuffed and uncuffed ETT sized ID 2.5 to 5.0 mm were evaluated in an in vitro set-up. Ease of device passage as well as the locations of an impaired passage within the ETT were assessed. Redundant samples were used for same sized ETT and all measurements were triple-checked in randomized order.

RESULTS

In total, 51 paired samples of uncuffed as well as cuffed paediatric ETT were tested. There were substantial differences in the ease of ETT passage concordantly for FOBs and AECs among different manufacturers, but also among the product lines from the same manufacturer for a given ID size. Restriction to passage most frequently was found near the endotracheal tube tip or as a gradually increasing resistance along the ETT shaft.

CONCLUSIONS

Current recommendations for dimensional equipment compatibility AECs and FOBs with ETTs do not appear to be completely accurate for all ETT brands available. We recommend that specific equipment combinations always must be tested carefully together before attempting to use them in a patient.

Health-related quality of life measurement after cholesteatoma surgery: comparison of three different surgical techniques

The objective of this study was to compare health-related quality of life (HRQOL) after sequential cholesteatoma surgery including exclusively transcanal technique (ETC), combined transcanal transmastoidal technique (TCM) and canal wall down surgery with obliteration (CWD). It was a clinical case study conducted in a tertiary referral center. 97 patients at least 12 months after cholesteatoma surgery were included. Interventions included sequential cholesteatoma surgery with ETC, TCM or CWD; ossiculoplasty with partial and total ossicular replacement prostheses. HRQOL assessed by Chronic Otitis Media Outcome Test 15 including an overall score and three subscores ('ear symptoms', 'hearing function' and 'mental health') as well as a general evaluation of HRQOL and the frequency of physician consultations, audiometric outcome related to HRQOL were the main outcome measures. Patients, who had undergone sequential cholesteatoma surgery, showed moderate restrictions in HRQOL postoperatively. Stratified for the three surgical techniques, patients receiving ETC tended to report lower restrictions in HRQOL. The ETC group offered a significantly lower value in the subscore 'ear symptoms'. The 'hearing function' was attributed to be the most restriction criteria for all techniques. The overall score and all subscores correlated moderately with the postoperative air conduction threshold. The strongest correlation coefficient was achieved for the subscore 'hearing function' (r(s) = 0.49, p < 0.001). Sequential cholesteatoma surgery offers acceptable moderate restrictions in HRQOL postoperatively. Patients receiving canal wall down surgery with obliteration showed equivalent limitations in HRQOL compared to closed techniques (ETC, TCM). The postoperative air conduction threshold was shown not to be a sufficient indicator for HRQOL. Therefore, disease-specific validated and reliable measuring instruments for HRQOL should be transferred from clinical research to clinical practice to provide an individualized postoperative assessment after cholesteatoma surgery.

[Intubation with a tube exchanger on an intubation trainer. Influence of tube tip position on successful intubation]

BACKGROUND

Securing the airway using a tube exchanger catheter is an important and useful technique in anesthesia. Its success is mainly hampered by tube tip impingement of laryngeal structures. Advancing the tracheal tube along its normal curvature via a tube exchanger catheter has a high risk of tube tip impingement mainly of right laryngeal structures. The authors achieved successful clinical experience by rotating the tracheal tube 90° anticlockwise (ventral tube tip position) before railroading the tube via a tube exchanger catheter or a fiber optic bronchoscope through the larynx.

AIM

The aim of the study was to investigate the influence of the tracheal tube tip position while intubating an airway trainer over a tube exchange catheter.

MATERIAL AND METHODS

Volunteer anesthetists with varying years of professional experience were asked to intubate an intubation mannequin (Laerdal Airway Management Trainer) using the orotracheal route with an established tube exchange catheter (Cook Airway Exchange Catheter, 11F). Two different brands of tracheal tubes (Rüsch and Covidien, ID 7.0 mm) were used in a randomized order, each with the tracheal tube tip at first positioned right (90°), then ventrally (0°), left (270°) and finally dorsally (180°), resulting in eight intubation attempts for each participant. To ensure the correct tube tip position the tube was withdrawn before every intubation attempt until the tube tip position was visualized. The oropharnyx, larynx, trachea and tube were sufficiently lubricated with silicon spray (Rüsch Silikospray). The tube and airway exchange catheter size selection were made according to the clinical trial of Loudermilk et al. Successful endotracheal intubation without resistance was recorded for each tube tip position and tracheal tube brand.

RESULTS

In total 20 anesthetists (13 consultants and 7 residents) with a median of 9.5 years (range 3-37 years) of professional experience participated in the study. Overall 160 intubation attempts were performed, 2 participants showed no successful intubation attempts at all and 38 out of 160 intubation attempts (23.8 %) were successful. Intubation success with the tracheal tube tip placed ventrally (0°) was 60 % followed by the left (270°) and right (90°) tracheal tube tip positions with 27.5 % and 7.5 % intubation success, respectively. With the tube tip placed dorsally (180°) none of the 40 intubation attempts were successful. Intubation attempts with the Rüsch tube were more successful (28.8 %) than those with the Covidien tube (18.8 %). Placing the tracheal tube tip ventrally, the Rüsch tube was twice as successful as the Covidien tube with 16 (80 %) versus 8 attempts (40 %, p = 0.011). There was no correlation between professional experience and intubation success (p = 0.362).

CONCLUSION

Tube insertion via an airway exchange catheter or a fiberoptic bronchoscope is a basic technique in anesthesia. Knowledge about the difficulties and their prevention are essential for every anesthetist. The gap between the airway exchange catheter, the fiber bronchoscope and the tube diameters is one of the major reasons for tube tip impingement. This investigation showed that intubation success via a tube exchange catheter, as investigated in an intubation mannequin, is considerably influenced by the tracheal tube tip position. A 90° anticlockwise rotation, placing the tracheal tube tip ventrally, considerably increased intubation success. This is of particular importance if an anesthesia department has no appropriately sized tube exchange catheters or fiber bronchoscope for every age group of patients.

[Peer teaching and peer assessment are appropriate tools in medical education in otorhinolaryngology]

BACKGROUND

The use of student tutors (peers) is an accepted method in medical education. In 2011, final year students of the otorhinolaryngology (ORL) department of the University Hospital in Dresden were appointed as peers for the clinical ORL examination. They assisted in the instruction of the clinical ORL examination (peer teaching, PT) and served as examiners (peer assessment, PA) in the final objective structured clinical examination (OSCE). The effect on the quality of education and examination was examined.

MATERIAL AND METHODS

248 medical students (5(th) year) were divided in 2 groups. They were trained and finally examined in the standardized clinical ORL examination by peers and/or physicians. Group I (n=118) was exclusively trained and examined by physicians and group II (n=130) by peers and physicians. The results of the OSCE were stratified for the 2 groups and in group II for the subgroups according to the instructors' and examiners' qualification (peer or physician). The students evaluated the internship and the instructors' and examiners' quality with a validated questionnaire.

RESULTS

In the OSCE, group I scored in the mean 59.9±4.9 points (max. 65). In group II the mean score was 58.3±4.3 points examined by the peers and 59.5±4.8 points for same performance assessed by the physicians. There were no statistical significant differences in the examination results when stratified for the instructors' and examiners' qualification. The evaluation results were consistently positive and identical when compared to the previous year without use of PT and PA and between the 2 groups and subgroups.

CONCLUSIONS

When using a standardized clinical examination routine peers can be used for PT and PA to appropriate tools in student's medical education without any decrease in the teaching and examination quality.

Growing experience with mTOR inhibitors in pediatric solid organ transplantation

Controlled trials of mTOR inhibitors in children following solid organ transplantation are scarce, although evidence from prospective single-arm studies is growing. Everolimus with reduced CNI therapy has been shown to be efficacious and safe in de novo pediatric kidney transplant patients in prospective trials. Prospective and retrospective data in children converted from CNI therapy to mTOR inhibition following kidney, liver, or heart transplantation suggest preservation of immunosuppressive efficacy. Good renal function has been maintained when mTOR inhibitors are used de novo in children following kidney transplantation or after conversion to mTOR inhibition with CNI minimization. mTOR inhibition with reduced CNI exposure is associated with a low risk for developing infection in children. Growth and development do not appear to be impaired during low-dose mTOR inhibition, but more studies are required. No firm conclusions can be drawn as to whether mTOR inhibitors should be discontinued in children requiring surgical intervention or whether mTOR inhibition delays progression of hepatic fibrosis after pediatric liver transplantation. In conclusion, current evidence suggests that use of mTOR inhibitors in children undergoing solid organ transplantation is efficacious and safe, but a number of issues remain unresolved and further studies are required.

Interactions between protein coated particles and polymer surfaces studied with the rotating particles probe

Nonspecific interactions between proteins and polymer surfaces have to be minimized in order to control the performance of biosensors based on immunoassays with particle labels. In this paper we investigate these nonspecific interactions by analyzing the response of protein coated magnetic particles to a rotating magnetic field while the particles are in nanometer vicinity to a polymer surface. We use the fraction of nonrotating (bound) particles as a probe for the interaction between the particles and the surface. As a model system, we study the interaction of myoglobin coated particles with oxidized polystyrene surfaces. We measure the interaction as a function of the ionic strength of the solution, varying the oxidation time of the polystyrene and the pH of the solution. To describe the data we propose a model in which particles bind to the polymer by crossing an energy barrier. The height of this barrier depends on the ionic strength of the solution and two interaction parameters. The fraction of nonrotating particles as a function of ionic strength shows a characteristic shape that can be explained with a normal distribution of energy barrier heights. This method to determine interaction parameters paves the way for further studies to quantify the roles of protein coated particles and polymers in their mutual nonspecific interactions in different matrixes.

[Evaluation of the Dresden Tympanoplasty Model (DTM)]

The training of microsurgical motor skills is essentiell for surgical education if the interests of the patient are to be safeguarded. In otosurgery the complex anatomy of the temporal bone and variations necessitate a special training before performing surgery on a patient. We therefore developed and evaluated a simplified middle ear model for acquiring first microsurgical skills in tympanoplasty.The simplified tympanoplasty model consists of the outer ear canal and a tympanic cavity. A stapes model is placed in projection of the upper posterior tympanic membrane quadrant at the medial wall of the simulated tympanic cavity. To imitate the annular ligament flexibility the stapes is fixed on a soft plastic pad. 41 subjects evaluated the model´s anatomical analogy, the comparability to the real surgical situation and the general model properties the using a special questionnaire.The tympanoplasty model was very well evaluated by all participants. It is a reasonably priced model and a useful tool in microsurgical skills training. Thereby, it closes the gap between theoretical training and real operation conditions.

[Operationalization of the clinical head and neck examination]

Standardized procedures support learning of complex psychomotoric activities. We standardized the clinical otolaryngology examination to provide an objective basis for its operationalization. The Impact of the standardization on the objective measureable learning success and the student's evaluation were determined.During their 1-week ENT internship 166 medical students learned the standardized clinical otolaryngology examination. At the end of this week they absolved an objective structured clinical examination (OSCE). The students evaluated both, the teaching (standardization) and examination method (OSCE) with 2 questionnaires.All students passed the exam with mean score of 60.3±3.5 (max. 65) points. By using the OSCE checklist 2 independent examiners appraised nearly identical examination performances. In both evaluations the students rated the teaching and examination design positive. All students greatly appreciated the standardized clinical examinations and considered it as are very important for learning practical skills.The standardization of clinical otolaryngology examination permits objective and reliable tests for learning progress and success. Furthermore transparency, process reliability and test quality are considerably improved. The student's evaluation clearly reflects the mentioned advantages.

Spin-spin interactions in organic magnetoresistance probed by angle-dependent measurements

The dependence of organic magnetoresistance (OMAR) on the orientation of the magnetic field has been investigated. In contrast with previous claims, a finite and systematic change in magnitude is observed when the orientation of the field is changed with respect to the sample. It is demonstrated that, to explain these effects, spin-spin interactions have to be included in the models previously suggested for OMAR. Dipole coupling and exchange coupling are introduced in combination with either an anisotropy of the orientation of the spin pairs or an anisotropy in the hyperfine fields.

[Lambliasis as differential diagnosis of MARSH type 3b]

Giardia lamblia is the most common human parasite with a worldwide distribution and fecal-oral way of transmission. Diagnostic procedures include stool examination and gastroduodenoscopy with biopsy or secret aspiration. In most cases histology reveals a dense accumulation of the parasites on the surface of the duodenal mucosa with no or only slight inflammation. In rare cases, a dense inflammatory infiltrate with severe mucosal atrophy and increased count of intraepithelial lymphocytes may be seen. If in such cases the amount of parasites is low, the histological picture may mimic celiac disease. The two presented cases demonstrate the close morphological relationship and show the importance of considering giardiasis in the differential diagnosis in patients with suspected celiac disease.

[Medical education in otorhinolaryngology in Germany. Implementation of the new licensing regulations for physicians]

BACKGROUND

In 2003 new regulations for the licensing of German physicians came into effect. The aim of this study was to survey the present status of realization in German otorhinolaryngology (ORL) university departments.

METHODS

A questionnaire containing 31 items was sent to all German ORL university departments.

RESULTS

A total of 31 (86%) ORL departments responded to the questionnaire. Most faculties reacted correctly in the practical realization of the new regulation demands. Regarding the quality of written and practical examinations, some changes have to be considered in order to maintain high quality standards.

CONCLUSION

The demands of the new licensing regulations have not yet been fully implemented. Therefore, medical education must gain importance in the daily clinical routine. Establishment of nationwide learning objectives and resources pooling for written examinations would be helpful.