[Interactive intraoperative annotation of surgical landmarks in student education to support learning efficiency and motivation]

BACKGROUND

The development of technological innovations has not only changed social life and the healthcare system, but also affects medical education. The aim of this pilot study was to evaluate whether students, when observing a microsurgical procedure of the temporal bone, gain an additional understanding of the anatomical structures and surgical site when visualization is used that provides identical views for the surgeon and viewer in 3D.

MATERIALS AND METHODS

During regular attendance tutorials, students were randomly assigned to three different groups: control group, 2D group, or 3D group. Evaluation questionnaires and intraoperative student annotation of the surgical view were used to assess the subjective didactic value of different visualization formats and resultant learning experiences for the students.

RESULTS

A total of 47 students were included in the investigations during conventional attendance tutorials. The majority indicated a high added value of the 3D visualization in terms of method (70%) and vividness (80%) compared to the 2D group and self-study; 69% of the students fully agreed with the statement that 2D and 3D visualization increases learning motivation and is a very good way to improve recognition of anatomical topography and structures.

CONCLUSION

New interactive visualization options in teaching promote learning efficiency and motivation among students. Especially 3D visualization and intraoperative annotation of the surgical view by the student is a useful didactic tool and increases the quality of clinical teaching. It supports the perception of anatomical topography and enables more focused surgical training.

Smartphone-based nystagmus diagnostics: development of an innovative app for the targeted detection of vertigo

BACKGROUND

In medicine, the symptom of dizziness is one of the most common multidisciplinary causes of emergency medical presentation. Attending physicians are often faced with difficult decisions when evaluating patients with dizziness. A rapid differential diagnostic decision must be made during the initial examination. The goal of this study, was to develop a smartphone-based app that can diagnose and qualify nystagmus. The app should enable differentiation between acute emergencies such as strokes ("central vertigo") and vestibular disorders ("peripheral vertigo") using and recognizing or analyzing the accompanying symptom "nystagmus".

MATERIALS AND METHODS

This prospective study was conducted at the Department of Otolaryngology, Head and Neck Surgery "Otto Körner", Rostock (Germany). The experimental study design consisted of two test runs and two control runs. In the two test runs, nystagmus was tracked and evaluated by caloric and optokinetic stimulation, respectively, through a custom-developed app. Sensitivity and correlation were calculated for the app's application performance and compared under different experimental conditions.

RESULTS

The patient sample included twenty healthy participants with a mean age of 25.6 years (± 2.2 SD) who participated in the study. The overall sensitivity of detection of nystagmus averaged 82.14% in the optokinetic stimulation test trials. There is no correlation regarding specific subject data and sensitivity.

CONCLUSIONS

The results of our experimental validation study show that a smartphone-based nystagmus app is a useful tool for vertigo diagnosis. The results of our analyses show that it is possible to diagnose nystagmus and determine shape or direction with the app.

Chronic otitis media following infection by non-O1/non-O139 Vibrio cholerae: A case report and review of the literature

We report a case of a chronic mesotympanic otitis media with a smelly purulent secretion from both ears and recurrent otalgia over the last five years in a six-year-old girl after swimming in the German Baltic Sea. Besides Staphylococcus aureus a non-O1/non-O139 Vibrio cholerae strain could be isolated from patient samples. An antibiotic therapy with ciprofloxacin and ceftriaxone was administered followed by atticotomy combined with tympanoplasty. We conclude that V. cholerae should not be overlooked as a differential diagnosis to otitis infections, especially when patients present with extra-intestinal infections after contact with brackish- or saltwater aquatic environments.

Evaluating the didactic value of 3D visualization in otosurgery

Introduction

Improvements of surgical visualization add value to the quality of clinical routine and offer the opportunity to improve surgical education of medical staff. The aim of this study was to determine whether otorhinolaryngology trainees gain additional comprehension of the anatomical structures and the surgical site when 3D visualization is used.

Methods

Data were collected from ENT trainees of microsurgical courses of the middle ear, inner ear and lateral skull base at four university ENT departments (Charité (Berlin), Martin Luther University Halle-Wittenberg (Halle/Saale), Ludwig Maximilian University (Munich) and Rostock University Medical Center). Participants were asked to complete a questionnaire assessing the subjective value of identical surgical field visualization in 3D for surgeon and observer.

Results

A total of 112 participants completed the questionnaire. The majority of participants stated a high additional value of 3D visualization compared to 2D visualization, with 75% fully agreeing to the statement that 3D visualization of the surgical field is superior to perceive the anatomical topography and structures compared to 2D representation. Participants encouraged the storage of data in online learning platforms.

Conclusion

The results show that 3D visualization with identical imaging for surgeon and observer is a useful tool in teaching of microsurgery. It addresses perception of anatomical topography and structures as well as conception of the surgical workflow.

Electronic supplementary material

The online version of this article (10.1007/s00405-020-06171-9) contains supplementary material, which is available to authorized users.

Air filters for indoor environments: Interlaboratory evaluation of the new international filter testing standard ISO 16890

Electret filters are widely used in HVAC systems to decrease particulate matter in indoor environments. The previous standard in Europe for testing air filters for general ventilation was EN 779. In July 2018, it was replaced by the new international standard ISO 16890. One major change is the discharging process: It is now performed by treating the filters with saturated isopropyl alcohol (IPA) vapor. The process is intended to simulate a worst-case scenario of the filtration efficiency due to the reduction of the electret effect. These minimal efficiencies are a principal part of the filter classification. Therefore, two round robin tests with different filter classes (F9 and F7 according to EN 779) and up to eleven participants were carried out to evaluate the new test method by comparing the filtration efficiencies and pressure drops before and after the IPA treatment. Pressure drop measurements showed no mechanical altering of the material due to the discharging process. The calculated filter classes had a maximum deviation of 5%. Even with different equipment, the results indicate that the new ISO 16890 seems to be a viable test standard and a decent replacement for previous national standards.

Intraoral voice recording-towards a new smartphone-based method for vocal rehabilitation

After laryngectomy, a new voice is needed. We present the first steps in the development of a smartphone-based method. A microphone is placed in the mouth to record the pseudo-whispering voice of laryngectomized patients. This recording is analyzed by voice recognition software followed by voice synthesis. Eventually, this will be performed on a smartphone. We placed a microphone at 10 different places inside and outside the mouth (two in front of the mouth (at 2 and 20 cm), five on the palate and three on the lower jaw) and made voice recordings in eight healthy men. These recordings were analyzed by voice recognition software. The text generated by the software was compared with the original text. Over all positions, the correct detection of words recorded in the mouth was 19.3% vs. 75.2% (p = 0.01) outside the mouth. In the mouth, recording taken on the maxilla (22.8%) was much better than on the mandible (13.5%) (p = 0.01). The optimum position for a microphone on the maxilla was at the highest point of the palate with 31.9% correct word identification there (p = 0.028). Further investigations have to be undertaken with forthcoming development of smartphone processing power and with development of a smartphone-based voice recognition application.

Microbiome and Culture Based Analysis of Chronic Rhinosinusitis Compared to Healthy Sinus Mucosa

The role of bacteria in chronic rhinosinusitis (CRS) is still not well understood. Whole microbiome analysis adds new aspects to our current understanding that is mainly based on isolated bacteria. It is still unclear how the results of microbiome analysis and the classical culture based approaches interrelate. To address this, middle meatus swabs and tissue samples were obtained during sinus surgery in 5 patients with CRS with nasal polyps (CRSwNP), 5 patients with diffuse CRS without nasal polyps (CRSsNP), 5 patients with unilateral purulent maxillary CRS (upm CRS) and 3 patients with healthy sinus mucosa. Swabs were cultured, and associated bacteria were identified. Additionally, parts of each tissue sample also underwent culture approaches, and in parallel DNA was extracted for 16S rRNA gene amplicon-based microbiome analysis. From tissue samples 4.2 ± 1.2 distinct species per patient were cultured, from swabs 5.4 ± 1.6. The most frequently cultured species from the swabs were Propionibacterium acnes, Staphylococcus epidermidis, Corynebacterium spp. and Staphylococcus aureus. The 16S-RNA gene analysis revealed no clear differentiation of the bacterial community of healthy compared to CRS samples of unilateral purulent maxillary CRS and CRSwNP. However, the bacterial community of CRSsNP differed significantly from the healthy controls. In the CRSsNP samples Flavobacterium, Pseudomonas, Pedobacter, Porphyromonas, Stenotrophomonas, and Brevundimonas were significantly enriched compared to the healthy controls. Species isolated from culture did not generally correspond with the most abundant genera in microbiome analysis. Only Fusobacteria, Parvimonas, and Prevotella found in 2 unilateral purulent maxillary CRS samples by the cultivation dependent approach were also found in the cultivation independent approach in high abundance, suggesting a classic infectious pathogenesis of odontogenic origin in these two specific cases. Alterations of the bacterial community might be a more crucial factor for the development of CRSsNP compared to CRSwNP. Further studies are needed to investigate the relation between bacterial community characteristics and the development of CRSsNP.

Sevoflurane at 1.0 MAC together with remifentanil and propofol produces clinically acceptable intubation conditions at the vocal cords: A prospective randomized study

Objective

The overall intubation conditions after tracheal intubation with remifentanil, propofol, and sevoflurane at 1.0 minimum alveolar concentration (MAC) are worse than with rocuronium at 0.45 mg/kg. Therefore, we compared the intubation conditions and laryngeal morbidity (vocal cord injuries, hoarseness, and sore throat) with sevoflurane at 1.2 and 1.4 MAC versus 1.0 MAC.

Methods

In this prospective clinical trial, 90 patients were randomized to 3 groups: the sevoflurane 1.0, 1.2, and 1.4 MAC groups. At 3 min, tracheal intubation was performed and the patients’ intubation conditions were assessed. The vocal cords were examined for injury by videolaryngoscopy. Additionally, the incidence and severity of laryngeal morbidity were compared between women and men.

Results

Acceptable intubation conditions were seen in 72% of the patients without significant differences between the groups. Overall, vocal cord injuries (oedema) occurred in three (4%) patients. Women reported sore throat more often than men (51% vs. 21%, respectively).

Conclusions

Intubation conditions were not improved with higher sevoflurane concentrations. The incidence and severity of sore throat were greater in women than men.

Trial registration: ClinicalTrials.Gov: NCT 01896245

[Otorhinolaryngology in the field of demography, growing outpatient care and regionalization]

BACKGROUND

Otorhinolaryngology (ENT) departments are strongly affected by current changes in the reimbursement schemes for inpatients. The study was designed to investigate these effects on the ENT Department in Rostock and selected comparison clinics, as well as to outline solutions.

METHODS

We analyzed diagnosis-related group (DRG) reports of the ENT Clinic at Rostock University Medical Center from 2013 to 2015, according to the size of the outpatient potential. Comparisons were made with other surgical departments such as maxillofacial surgery and ophthalmology in terms of average length of stay and the resulting deductibles. We also compared billing as day surgery and complete outpatient surgery for the main small surgical procedures such as tonsillectomy and septum surgery. Finally, we compared the discounts with 22 ENT departments in other maximum care hospitals.

RESULTS

The average case mix index of an ENT department in Germany is 0.75, case load average of 2,500 patients and common length of stay 4.1 days. In a typical academic ENT department as in Rostock, health plans usually discount around 500 T€ (thousand euro), which is considerably higher than comparable departments, e.g., oral and maxillofacial surgery or ophthalmology departments. However, discounts on a DRG for inpatient surgery is still approximately 1,000 € more revenue than surgery in an outpatient setting. The benchmark analysis shows that health plans in rural areas are more likely to accept inpatient surgery with discounts for small procedures than strict billing according to outpatient reimbursement schemes.

CONCLUSION

These effects can result in an insufficient cost effectiveness of ENT departments in Germany. As a consequence, substantial restructuring of the in- and outpatient treatment seems necessary, also for academic ENT departments, e.g., in the form of day surgery or ambulatory surgical centers, outpatient clinics with special contracts and specialized inpatient surgery. However, this results in greater demands on the training of young physicians and management of patient flows within the department.

Positioning Accuracy in Otosurgery Measured with Optical Tracking

Objectives

To assess positioning accuracy in otosurgery and to test the impact of the two-handed instrument holding technique and the instrument support technique on surgical precision. To test an otologic training model with optical tracking.

Study Design

In total, 14 ENT surgeons in the same department with different levels of surgical experience performed static and dynamic tasks with otologic microinstruments under simulated otosurgical conditions.

Methods

Tip motion of the microinstrument was registered in three dimensions by optical tracking during 10 different tasks simulating surgical steps such as prosthesis crimping and dissection of the middle ear using formalin-fixed temporal bone. Instrument marker trajectories were compared within groups of experienced and less experienced surgeons performing uncompensated or compensated exercises.

Results

Experienced surgeons have significantly better positioning accuracy than novice ear surgeons in terms of mean displacement values of marker trajectories. The instrument support and the two-handed instrument holding techniques significantly reduce surgeons’ tremor. The laboratory set-up presented in this study provides precise feedback for otosurgeons about their surgical skills and proved to be a useful device for otosurgical training.

Conclusions

Simple tremor compensation techniques may offer trainees the potential to improve their positioning accuracy to the level of more experienced surgeons. Training in an experimental otologic environment with optical tracking may aid acquisition of technical skills in middle ear surgery and potentially shorten the learning curve. Thus, simulated exercises of surgical steps should be integrated into the training of otosurgeons.

[Inpatient vs. outpatient costs analysis of septumplasty in Germany]

The septumplasty is realized inpatient and outpatient in different countries. Caused by the pressure of reduction of expenses there is the question of the economic benefit if done outpatient in Germany. A comparison of the inpatient and outpatient gratification will be done. There is a yearly potential of cost reduction of 180 million euro, if the operation would be done as an outpatient procedure. From the hospital view actual there is no economical recommendation doing an outpatient septumplasty caused by the poor outpatient remuneration. That's why an adjustment of the outpatient remuneration should be done. Actual there is no medical or economical recommendation doing the septumplasty as an outpatient procedere.

Conservative management of post-intubation tracheal tears-report of three cases

Iatrogenic tracheal rupture is a rare complication after intubation. We present three patients with tracheal tears. In all of these patients, a common finding was a lesion of the posterior tracheal wall with postoperative subcutaneous and emphysema as the first clinical sign of the rupture. Diagnosis and follow-up were based on clinical and endoscopic findings and chest computed tomography (CT) scans. In our cases with progressive subcutaneous and mediastinal emphysema or dyspnea, we performed a tracheotomy and bypassed the lesion with a tracheostomy tube to avoid an increase in air leakage into the mediastinum. Under broad-spectrum antibiotic therapy, no mediastinitis occurred and all patients survived without sequelae. Closure of tracheostomy was scheduled for 1-2 months after tracheal injury. Analysis of surgical and anesthesiological procedures revealed no abnormalities and the accumulation of tracheal injuries was considered as accidental. We found that in clinically stable patients with spontaneous breathing and with no mediastinitis, a conservative management of tracheal tears is a safe procedure.

[Inpatient vs. outpatient costs analysis of the tonsillectomy]

BACKGROUND

The tonsillectomy is realized inpatient and outpatient in different countries. Caused by the pressure of reduction of expenses there is the question of the economic benefit if done outpatient in Germany.

MATERIAL AND METHODS

A comparison of the inpatient and outpatient gratification will be done.

RESULTS

There is a yearly potential of cost reduction of 213.5 million euro, if the operation would be done as an outpatient procedure. From the hospital view there is no economical recommendation doing an outpatient tonsillectomy.

CONCLUSION

With simultaneous consideration of economical reasons, the medical quality and macroeconomic reasons there is no recommendation doing the tonsillectomy as an outpatient operation in Germany.

[The costs for different voice prostheses depending on the lifetime]

Voice prostheses are available in different types of architecture und from different producers. Especially the ones with antifungal properties are characterized by a high pricing. The aim of this paper is to check, whether these prices are reflected by the prosthesis life time.A Benchmarking with usage of mean lifetime and prosthesis costs. Comparing Provox 1, Provox 2, Provox Vega, Provox ActiValve, ESKA-Herrmann, Blom Singer Classic, Phonax, Blom Singer Advantage.The voice prosthesis Provox 1 offers the best price-lifetime-ratio (1.0). It's 6.7-times higher than the one of the Provox ActiValve (0.15). In addition, the classic prostheses Provox 2 (0.53), Blom Singer Classic (0.54) and ESKA-Herrmann (0.72) offer a good ratio compared to Provox 1, too.The mean lifetime of the voice prostheses do not reflect the pricing. The Provox 1 offers the best ratio and should be used as a reference in pricing the prostheses.

[Recurrent epistaxis of unknown origin. A rare differential diagnosis and its treatment]

We present the case report on a 66-year-old male patient who appeared in our clinic with recurrent epistaxis. Anterior rhinoscopy during acute bleeding yielded no information on the origin of hemorrhage. On renewed epistaxis, angiography was performed on which an arteriovenous malformation in the sphenoid sinus could be identified as the cause of epistaxis. Embolization of afferent vessels successfully reduced the malformation and stopped the bleeding. In cases of recurrent epistaxis, especially in combination with an unremarkable anterior rhinoscopy, angiography is recommended for the detection of life-threatening vessel malformations.

[The vocal rehabilitation with ESKA-Herrmann voice prosthesis. a report of a 10 years' experience]

ESKA-Herrmann voice prosthesis are available for almost 30 years and are used for the vocal rehabilitation of laryngectomees. Nevertheless there are no studies about this voice prosthesis. Especially because of the smaller external diameter of 5.5 mm differents to other voice prostheses may be expected.We analyzed the 10-year patient documentation in retrospect.67 patients (63 m/4f) got the ESKA-Herrmann voice prosthesis, which could be used with a mean lifetime of 131.4 days. The main reason of changing the prostheses were dislocation (34/119), loss by coughing (34/119) and the leakage around the prostheses. In total a good voice was documented in 83.9% of the prostheses.ESKA-Herrmann voice prostheses are an alternative to other prostheses. Because of the smaller external diameter the dislocation and loss of the prosthesis occur more often than other models. But it's the only model that allows a designated spontaneous closure of the trachea-esophageal fistula after prosthesis removal.

[Post-traumatic aneurysm of the dorsal nasal artery. A rarity following blunt trauma]

We report the case of a 69-year-old male patient who appeared in our clinic with persistent swelling on the right middle nasal bridge of 3 months' standing following blunt trauma. On physical examination the swelling was pulsatile and a flow was identified on color Doppler sonography. MRT of the head demonstrated an aneurysm of the dorsal nasal artery. We treated the aneurysm in an open surgical procedure under local anaesthesia. Due to the superficial position of this artery, open injuries are common after blunt nasal trauma. Some cases of aneurysm of the temporal artery have been described. Aneurysm of the dorsal nasal artery is a rare result of nasal trauma.

Combination of a continuous-wave optical parametric oscillator and a femtosecond frequency comb for optical frequency metrology

We combined a tunable continuous-wave optical parametric oscillator and a femtosecond Ti:sapphire laser frequency comb to provide a phase-coherent bridge between the visible and the mid-infrared spectral ranges. As a first demonstration of this new technique we performed a direct frequency comparison between an iodine-stabilized Nd:YAG laser at 1064 nm and an infrared methane optical frequency standard at 3.39 microm.