Implantation and reimplantation: epidemiology, etiology and pathogenesis over the last 30 years

INTRODUCTION

Due to the increasing number of cochlear implant (CI) recipients, growing indications, and the aging population, the reimplantation of CI recipients has become a focus of attention. The aim of this study is to examine the causes, timing, and postoperative speech understanding in a large cohort over the past 30 years.

METHODS

A retrospective data analysis was conducted on over 4000 CI recipients and 214 reimplanted children and adults from 1993 to 2020. This involved collecting and comparing data on causes, manufacturer information, and demographic data. In addition, a comparison of speech understanding in Freiburg monosyllables and numbers before and after reimplantation was carried out.

RESULTS

Children did not exhibit elevated rates of reimplantation. The overall reimplantation rate in the entire cohort was 5%. The CI overall survival rate after 10 years in the entire cohort was 95.2%. Device failure was the most common reason for reimplantation, with 48% occurring within the first 5 years after implantation. The second most common reason was medical complications, with the risk of reimplantation decreasing as more time passed since the initial implantation. There were no significant differences in Freiburg numbers and monosyllable comprehension before and after reimplantation, both in the overall cohort and in the subcohorts based on indications. Even a technical upgrade did not result in a significant improvement in speech understanding.

DISCUSSION

There was no significant difference in the frequency of reimplantation based on patient age, especially when comparing children and adults. Device failure is by far the most common indication for reimplantation, with no significant difference in implant survival between manufacturers. Patients most often choose the same manufacturer for reimplantation. The likelihood of reimplantation decreases with increasing time since the initial implantation. The indication for reimplantation should be carefully considered, as on average, no improved speech understanding is achieved, regardless of the cause, even with a technical upgrade.

Evaluation of insertion quality of a slim perimodiolar electrode array

OBJECTIVES

The influence of cochlear morphology and electrode array design on scalar position and dislocation rates is of great interest in CI surgery. The aim of this study is to evaluate scalar position and specific points of dislocation in relation to cochlear morphology in patients implanted with a new slim perimodiolar electrode array.

MATERIALS AND METHODS

Patients were implanted using the slim modiolar electrode array (= SMA) (= 532/632 electrode array of Cochlear™). Postoperative imaging was performed via cone beam computed tomography (CBCT) and the scans were analyzed regarding cochlear morphology (distances A and B and cochlear height), scalar location of the electrode array, basal insertion depth and apical insertion angle. Furthermore, electrode array design and surgical protocols were evaluated.

RESULTS

81 ears implanted with the SMA were retrospectively included. We evaluated 3 electrode array tip fold over intraoperatively via X-ray imaging and performed revision during the same surgery. The CBCT scans showed 76 initial scala tympani (ST) insertions without dislocation. Two ears showed a dislocated array, one at 77° and the other at 163°. Three arrays were inserted into scala vestibuli (SV) via cochleostomy. These patients showed no signs of obliteration. Cochlear morphology showed no influence on angular insertion depth and scalar position.

CONCLUSIONS

The SMA showed a very low rate of scalar dislocations due to its slim electrode array design (2.7%). We could find a learning curve regarding the handling and the risk of dislocation and tip fold over with this electrode array. The rate of intraoperative tip fold over detection via X-ray imaging was 3.7%. Therefore, we highly recommend X-ray imaging and transimpedance matrix measurements within the surgery protocol. Scala vestibuli insertions happened in patients with cochleostomy only. We could identify two specific points of dislocation depending on electrode array design.

Manipulation of the nuclear envelope-associated protein SLAP during mammalian brain development affects cortical lamination and exploratory behavior

Here, we report the first characterization of the effects resulting from the manipulation of Soluble-Lamin Associated Protein (SLAP) expression during mammalian brain development. We found that SLAP localizes to the nuclear envelope and when overexpressed causes changes in nuclear morphology and lengthening of mitosis. SLAP overexpression in apical progenitors of the developing mouse brain altered asymmetric cell division, neurogenic commitment and neuronal migration ultimately resulting in unbalance in the proportion of upper, relative to deeper, neuronal layers. Several of these effects were also recapitulated upon Cas9-mediated knockdown. Ultimately, SLAP overexpression during development resulted in a reduction in subcortical projections of young mice and, notably, reduced their exploratory behavior. Our study shows the potential relevance of the previously uncharacterized nuclear envelope protein SLAP in neurodevelopmental disorders.

[Insertion of a second electrode array-a rare complication of CI reimplantation. German version]

Due to a technical defect or a medical indication, it may be necessary to explant a cochlear implant. This case report shows that there is the risk of encountering a nonremovable electrode array-as described here from the scala tympani-during cochlear reimplantation. In the present case, insertion of a second electrode array into the free and nonobstructed scala vestibuli was successful. Nonetheless, the indication for reimplantation must be carefully considered, especially in patients with tolerable limitations with little or no loss of speech understanding. Furthermore, surgery should not be performed solely because an implant upgrade is desired.

Insertion of a second electrode array-a rare complication of CI reimplantation

Due to a technical defect or a medical indication, it may be necessary to explant a cochlear implant. This case report shows that there is the risk of encountering a nonremovable electrode array-as described here from the scala tympani-during cochlear reimplantation. In the present case, insertion of a second electrode array into the free and nonobstructed scala vestibuli was successful. Nonetheless, the indication for reimplantation must be carefully considered, especially in patients with tolerable limitations with little or no loss of speech understanding. Furthermore, surgery should not be performed solely because an implant upgrade is desired.

Subsea permafrost organic carbon stocks are large and of dominantly low reactivity

Subsea permafrost carbon pools below the Arctic shelf seas are a major unknown in the global carbon cycle. We combine a numerical model of sedimentation and permafrost evolution with simplified carbon turnover to estimate accumulation and microbial decomposition of organic matter on the pan-Arctic shelf over the past four glacial cycles. We find that Arctic shelf permafrost is a globally important long-term carbon sink storing 2822 (1518-4982) Pg OC, double the amount stored in lowland permafrost. Although currently thawing, prior microbial decomposition and organic matter aging limit decomposition rates to less than 48 Tg OC/yr (25-85) constraining emissions due to thaw and suggesting that the large permafrost shelf carbon pool is largely insensitive to thaw. We identify an urgent need to reduce uncertainty in rates of microbial decomposition of organic matter in cold and saline subaquatic environments. Large emissions of methane more likely derive from older and deeper sources than from organic matter in thawing permafrost.

Association of polymorphous light eruption with NOD-2 and TLR-5 gene polymorphisms

BACKGROUND

Polymorphous light eruption (PLE) is a common, immunologically mediated, photosensitive skin disease. After ultraviolet-B (UV-B) irradiation, patients with PLE show reduced Langerhans cell (LC) depletion in the epidermis, which results in a non-suppressive microenvironment in the skin. Interestingly, severe acute graft-versus-host-disease (aGvHD) occurred in stem cell transplanted patients that showed no or incomplete depletion of LCs after UVB-irradiation. Genetic variation in nucleotide-binding oligomerization domain 2 (NOD-2) and toll-like receptor 5 (TLR-5) genes also confers susceptibility to aGvHD.

OBJECTIVES

We hypothesized that PLE is associated with genetic variation in the NOD-2 and TLR-5 genes.

METHODS

We investigated single nucleotid polymorphisms (SNPs) of NOD-2 (R702W, G908R, 3020Cins) and TLR-5 (A592S, P616L, N392STOP) in skin biopsies of PLE-patients (n=143) and in healthy controls (n=104) using restriction fragment-length polymorphism analysis.

RESULTS

The frequency of NOD-2 alleles with the SNP R702W was significantly higher in PLE than in controls (31.8% vs 6.3%; p<0.0001), and homozygous carriers of this mutation were more common in PLE (27.9% vs 0%; p<0.0001). For SNP 3020Cins, the allele frequency (7.3% vs 0.7%; p=0.0025) and the number of heterozygotes (14.7% vs 1.3%; p=0.0019) were higher in PLE. The frequency of alleles with the N392STOP SNP of the TLR5 gene, which is associated with a truncated, non-functional receptor, was significantly higher in PLE (21% vs 5%; 7% vs 1% homozygotes, 28% vs 8% heterozygotes; p<0.0001). The other SNPs did not differ significantly.

CONCLUSIONS

This study yielded a high frequency of functional SNPs in the NOD-2 and TLR-5 genes in PLE. The same SNPs are associated with aGvHD and there are similarities in the reaction of LCs after UVB-irradiation between aGvHD and PLE. This leads to the hypothesis that PLE-patients may be more susceptible to developing GvHD after stem-cell transplantation, an assumption that needs to be investigated further.

Hearing outcome after tympanoplasty type III

Purpose

We assessed overall hearing outcome after tympanoplasty type III in chronically infected ears with cholesteatoma (CH) and without cholesteatoma: otitis media chronica mesotympanalis, tympanosclerosis, and adhesive process (COM_T_AP).

Methods

303 surgeries were evaluated: 229 CH-group and 74 COM_T_AP-group. Air-bone gaps (PTA-ABG) with pure-tone averages (PTA-4) at four frequencies (0.5, 1, 2 and 4 kHz) were compared preoperatively, early postoperatively (< 40 days) and late postoperatively (40–400 days). Hearing outcome was compared in various types of middle-ear reconstruction and in smokers and non-smokers. Correlations between hearing outcome and predictive staging indices were evaluated: Middle Ear Risk-Index (MER-I) and Ossiculoplasty Outcome Parameter Staging-Index (OOPS-I).

Results

Mean PTA-ABG in the CH-group increased from 20.9 ± 11.3 dB to 22.3 ± 10.4 dB early postoperatively and decreased significantly to 19.2 ± 10.1 dB late postoperatively. Mean PTA-ABG in the COM_T_AP-group decreased significantly from 27.3 ± 10.9 dB to 20.6 ± 10.9 dB early postoperatively and decreased to 20.0 ± 12.2 dB late postoperatively. No significant difference was seen between PTA-ABG-closures of partial or total ossicular replacement prosthesis (PORP/TORP) and cartilage ossiculoplasty in the CH-group. Patients receiving TORP showed a significantly higher preoperative PTA-ABG. All reconstruction types exhibited postoperative PTA-ABG around 20 dB. In the COM_T_AP-group, smokers had a significantly higher mean PTA-ABG early postoperatively; this equalized with that of non-smokers late postoperatively. PTA-ABG-closures and MER-I or OOPS-I were not significantly correlated.

Conclusion

Tympanoplasty type III maintains hearing in patients with cholesteatoma and significantly improves hearing in chronically inflamed ears without cholesteatoma. All investigated ossicular replacement prostheses are equally beneficial. Healing postoperatively takes longer in smokers, but they eventually catch up with non-smokers.

Active transcutaneous bone-anchored hearing implant: how I do it

BACKGROUND

The Cochlear™ Osia® System leaves a retroauricular bump that can cause discomfort and poor aesthetic outcome.

METHOD

To reduce the retroauricular bump, we introduced an implant well in the bone behind the ear for the transducer. We used cutting and diamond drills to create the implant well with an average depth of 4-5 mm. The surgical time including the implant well (40 min) was within the range of reported average surgical time (52 min).

CONCLUSION

Introduction of an implant well resulted in a better aesthetic outcome and improved patients' comfort. The reduced distance between BI300 and ear canal might improve audiological outcome.

[Deafness after COVID-19? German version]

This article presents a case of sudden bilateral deafness in the context of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection and resultant coronavirus disease 2019 (COVID-19). After treatment in the intensive care unit for acute respiratory distress syndrome and acute kidney failure, hearing ability had drastically changed. While hearing had been subjectively normal before the infection, deafness was now measured on the left and profound hearing loss on the right ear. The patient was treated with cochlea implants on the left and a hearing aid in the right ear. The hearing loss is most likely a complication of COVID-19.

Quality of cochlear implant rehabilitation under COVID-19 conditions

Background

The rehabilitation process following cochlear implant (CI) surgery is carried out in a multimodal therapy according to German national guidelines and includes technical and medical aftercare. In times of the corona pandemic surgery and rehabilitation appointments were cancelled or delayed leading to a more difficult access to auditory rehabilitation. Newly implemented hygiene modalities due to the SARS-CoV‑2 pandemic have changed medical aftercare and the rehabilitation process. The aim of this study was to evaluate the quality of rehabilitation under corona conditions.

Material and methods

An anonymous survey of adult cochlear implant patients was carried out by a non-standardized questionnaire. Demographics were analyzed and the quality of medical aftercare, speech therapy, technical aftercare, psychological support and the hygiene modalities were compared to previous rehabilitation stays.

Results

In total 109 patients completed the questionnaire. The quality of rehabilitation and individual therapy were rated as qualitatively similar or improved. The threat of the pandemic and fear of corona were rated unexpectedly high with 68% and 50%, respectively. The hygiene measures during the rehabilitation stay eased subjective fears at the same time. The majority of patients were annoyed by wearing face masks but visors, protection shields and social distancing were more tolerated.

Conclusion

The implementation of the new hygiene modalities within the therapeutic rehabilitation setting was well-accepted by patients allowing access to auditory rehabilitation. A successful rehabilitation should ensure a fear-free environment by adhering to the necessary hygiene modalities.

Electronic supplementary material

The online version of this article (10.1007/s00106-020-00923-z) includes the study questionnaire. Article and supplementary material are available at www.springermedizin.de. Please enter the title of the article in the search field, the supplementary material can be found under “Ergänzende Inhalte”.

Relationships among gastrointestinal symptoms, sleep problems, challenging behaviour, comorbid psychopathology and autism spectrum disorder symptoms in children and adolescents with 15q duplication syndrome

BACKGROUND

Comorbidity is the presence of at least two disorders in one person at one time. This study examined the frequency of gastrointestinal (GI) symptoms, sleep problems, comorbid psychopathology, challenging behaviour and autism spectrum disorder (ASD) symptoms in children and adolescents with duplication 15q syndrome (Dup15q), aged 3-17 years. This study also examined whether challenging behaviour in Dup15q is predicted by age, gender, presence of an intellectual disability, sleep problems, GI symptoms and comorbid psychopathology.

METHOD

Parental measures were completed by 101 parents of children and adolescents with Dup15q. Questionnaires were composed of the Children's Sleep Habits Questionnaire, Behavior Problems Inventory - Short Form, GI Symptom Inventory, Social Communication Questionnaire and the Child Behavior Checklist.

RESULTS

Sleep problems (94%), GI symptoms (87%) and challenging behaviour (100%) were common comorbidities represented in the sample in this study. Significant relationships were found between challenging behaviour and the presence of co-occurring sleep problems, GI symptoms, comorbid psychopathology and ASD symptoms. Further analysis revealed that these comorbidities also predicted challenging behaviour.

CONCLUSION

This research demonstrated the importance of studying the relationships between GI symptoms, sleep problems, comorbid psychopathology, ASD symptoms and challenging behaviour in Dup15q and how these conditions can shape the Dup15q phenotype.

[Navigated endoscopically controlled transtympanic resection of an infracochlear cholesteatoma recurrence. German version]

An infracochlear cholesteatoma of the petrous apex with direct contact to the internal carotid artery (ICA) is rare. Due to the risk of cochlear injury with consecutive deafness or injury of the ICA, precise preoperative planning of the approach and strategy is recommended, as well as thorough preoperative counseling of the patient for their informed consent. This case report presents navigated endoscopically controlled transtympanic resection of such a cholesteatoma recurrence. Hearing capacity was not impaired and the patient shows no signs of recurrence.

Speech Recognition in Noise in Single-Sided Deaf Cochlear Implant Children on Using Adaptive Digital Microphone Technology

BACKGROUND

 Previous research demonstrated benefits of adaptive digital microphone technologies (ADMTs) in adults with single-sided deafness (SSD) having a cochlear implant (CI). Children with SSD are especially affected by background noise because of their noise exposure in kindergarten and school.

PURPOSE

 This article aims to evaluate possible effects of ADMT on speech recognition in background noise in children with SSD who use a CI.

STUDY SAMPLE

 Ten children between 5 and 11 years of age were included.

DATA COLLECTION AND ANALYSIS

 Speech recognition in noise was assessed for one frontal distant and two lateral speakers. The speech stimulus was presented at a speech level of 65 dB(A) and noise at a level of 55 dB(A). For the presentation condition with one frontal speaker, four listening conditions were assessed: (1) normal-hearing (NH) ear and CI turned off; (2) NH ear and CI; (3) NH ear and CI with ADMT; and (4) NH ear with ADMT and CI. Listening conditions (2) to (4) were also tested for each lateral speaker. The frontal speaker was positioned directly in front of the participant, whereas the lateral speakers were positioned at angles of 90 degrees and -90 degrees to the participant's head.

RESULTS

 Children with SSD who use a CI significantly benefit from the application of ADMT in speech recognition in noise for frontal distant and for lateral speakers. Speech recognition improved significantly with ADMT at the CI and the NH ears.

CONCLUSION

 Application of ADMT significantly improves speech recognition in noise in children with SSD who use a CI and can therefore be highly recommended. The decision of whether to apply ADMT at the CI NH ear or bilaterally should be made for each child individually.

[Quality of cochlear implant rehabilitation under COVID-19 conditions. German version]

Hintergrund

Die Rehabilitation nach CI(Cochleaimplantat)-Operation erfolgt leitliniengerecht durch eine multimodale Therapie, technische Anpassungen des Sprachprozessors und medizinische Nachsorge. Zu Zeiten der Corona-Pandemie wurde für die Patienten der Zugang zur auditorischen Rehabilitation verzögert oder erschwert. Die neuen Hygienemaßnahmen durch die SARS-Cov-2-Pandemie verändern auch die medizinische Nachsorge und Rehabilitation nach CI. Ziel der Untersuchung war es, die Qualität der Rehabilitation unter Corona-Bedingungen zu evaluieren.

Material und Methoden

Wir führten eine anonyme Befragung erwachsener Rehabilitanden mittels nichtstandardisiertem Fragebogen durch. Beurteilt wurden im Vergleich zu den Voraufenthalten die Qualität der ärztlichen Betreuung, der Sprach- und Musiktherapie, der technischen Anpassung und der psychologischen Betreuung sowie der Einsatz der Hygienemaßnahmen.

Ergebnisse

Insgesamt 109 Rehabilitanden beantworteten den Fragebogen. Die Qualität der Rehabilitation und der Therapien wurde als qualitativ unverändert oder besser eingeschätzt. Die Gefährlichkeit der Pandemie, aber auch die Angst in der derzeitigen Situation gaben die Rehabilitanden zu einem unerwartet hohen Prozentsatz mit 68 bzw. 50 % an. Gleichzeitig konnten die getroffenen Hygienemaßnahmen die Patienten subjektiv während des Aufenthalts entlasten. Der Mund-Nasen-Schutz war für die Mehrheit sehr störend, Visiere, Spuckschutz bzw. Abstandsgebot wurden eher toleriert.

Schlussfolgerungen

Die Umsetzung der Hygienemaßnahmen im therapeutischen Setting der CI-Rehabilitation wird von den Rehabilitanden akzeptiert und erlaubt den Zugang zur auditorischen Rehabilitation. Ziel einer erfolgreichen CI-Rehabilitation sollte eine möglichst angstfreie Behandlung unter Wahrung der Hygieneregeln sein.

Zusatzmaterial online

Die Online-Version dieses Beitrags (10.1007/s00106-020-00922-0) enthält den Studienfragebogen. 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“.

Widespread energy limitation to life in global subseafloor sediments

Microbial cells buried in subseafloor sediments comprise a substantial portion of Earth's biosphere and control global biogeochemical cycles; however, the rate at which they use energy (i.e., power) is virtually unknown. Here, we quantify organic matter degradation and calculate the power utilization of microbial cells throughout Earth's Quaternary-age subseafloor sediments. Aerobic respiration, sulfate reduction, and methanogenesis mediate 6.9, 64.5, and 28.6% of global subseafloor organic matter degradation, respectively. The total power utilization of the subseafloor sediment biosphere is 37.3 gigawatts, less than 0.1% of the power produced in the marine photic zone. Aerobic heterotrophs use the largest share of global power (54.5%) with a median power utilization of 2.23 × 10-18 watts per cell, while sulfate reducers and methanogens use 1.08 × 10-19 and 1.50 × 10-20 watts per cell, respectively. Most subseafloor cells subsist at energy fluxes lower than have previously been shown to support life, calling into question the power limit to life.

Influence of single-sided deafness on the auditory capacity of the better ear

BACKGROUND

Patients with single-sided deafness (SSD) are limited by their asymmetric hearing in various areas of everyday life.

OBJECTIVE

The aim of this investigation was to perform an age-correlated comparison of the hearing threshold of the better ear of SSD patients with a normal-hearing (NH) reference cohort. In addition, the potential influence of etiology, duration of deafness, and cochlear implantation (CI) of the poorer ear on the peripheral hearing ability of the better ear was investigated.

MATERIALS AND METHODS

In a multicenter study, the mean bone conduction hearing threshold of the better ear of 413 adult SSD patients was compared with that of an NH cohort drawn from ISO 7029:2017 for the frequencies 0.5, 1, 2, and 4 kHz.

RESULTS

SSD patients showed significantly poorer hearing in the better ear compared to the age-correlated group of NH subjects. CI, duration of deafness, and etiology had no significant effect on the hearing ability of the better ear.

CONCLUSION

The origin of the poorer hearing of the better-hearing ear of SSD patients compared to an age-correlated NH cohort is still unclear. It is most likely a combination of different anatomical, immunological, etiological, and microcirculatory causes, which lead to poorer hearing of the better-hearing ear in SSD patients.

[Dichotic speech recognition with cochlear implants]

BACKGROUND

Dichotic speech recognition of side-separated speech stimuli requires their central nervous processing and has been used since the 1950s in a variety of clinical settings.

OBJECTIVE

The objective of this study was to investigate the dichotic speech recognition of normal-hearing (NH) subjects, cochlear implant (CI) recipients with single-sided deafness (SSD), and bilateral CI (BilCI) recipients with the dichotic discrimination test according to Feldmann.

MATERIALS AND METHODS

The speech recognition of ten adult NH subjects, ten SSD CI recipients, and ten BilCI recipients was determined at 65 dB SPL or 65 dB SPL equivalent for monotic presentation of trisyllabic nouns of the Feldmann test (NH subjects: better ear, poorer ear; SSD CI recipients: NH ear, CI; BilCI recipients: better CI, poorer CI) and for dichotic, i.e., simultaneous side-separated, presentation.

RESULTS

The NH subjects showed significantly poorer speech recognition for dichotic presentation than for monotic presentation. Speech recognition of SSD CI recipients was significantly worse with the CI than with the NH ear for both monotic and dichotic presentation. For both presentation conditions, BilCI recipients obtained significantly lower speech recognition with the poorer CI compared to the better CI. With each of the two CI, BilCI recipients had significantly worse speech recognition for dichotic presentation than for monotic presentation.

CONCLUSION

All three study groups-NH subjects, SSD CI recipients, and BilCI recipients-were able to recognize dichotically presented speech with both ears. For SSD CI recipients, there was no negative effect of the CI on speech recognition with the NH ear for dichotic presentation.

[Incomplete partition type III revisited-long-term results following cochlear implant. German version]

BACKGROUND

Incomplete partition type III (IP III) is defined by a missing lamina cribrosa between the cochlea and the internal auditory canal (IAC). Cochlear implantation (CI) may result in an insertion of the electrode array into the IAC. The aim of this study is to evaluate CI surgery protocols, long-term audiological outcome, mapping and electrophysiological data after CI in IP III patients.

MATERIALS AND METHODS

Nine IP III patients were implanted with perimodiolar electrode arrays between 1999 and 2014; eight of them were included in this study. We evaluated mapping data, stapedius reflexes, electrode impedances and ECAP thresholds. We matched them with 3 CI patients each with normal cochlear morphology regarding sex, age, side, implant type and surgical date. Speech discrimination was evaluated with the Oldenburger sentence test for adults, Göttingen audiometric speech test for children and the Freiburger monosyllabic word test.

RESULTS

3 years after CI IP III patients showed a significant increase in pulse width, calculated electric load and electrode impedances in basal electrodes. Intraoperative electrically-evoked stapedius reflexes could be measured in all patients. Speech recognition scores were lower than average scores for matched patients, but without statistical significance.

CONCLUSIONS

The significant increase of pulse width, electric load and electrode impedances of basal electrodes over time seem to be characteristic for IP III patients probably occurring due to fibrosis and neurodegeneration of the cochlear nerve. The long term audiological results are stable. Intraoperative imaging and stapedius reflexes are highly recommended to control the right position of the electrode array.

Analysis of the melt spreading and MCCI during the ex-vessel phase of a severe accident in WWER-1000

The paper presents analysis results of melt spreading and core-concrete interactions in the containment of a WWER-1000 plant during the ex-vessel phase of a severe accident. The failure of the vessel takes place 8 h 35 min after the initiation of the accident. It has been assumed that the whole area of the containment floor is available for spreading, i.e. the door between the reactor cavity and the main part of the containment is not locked. The melt flow rate from the reactor pressure vessel was used as a boundary condition. The simulation of the melt spreading was performed with the LAVA code. The calculated spreading area varies from 60 to 100 m2 depending on the assumed values of the melt properties. The results from the LAVA calculations were used in parallel for COCOSYS and MELCOR calculations to study the core-concrete interactions. From the analyses it turned out: a larger spreading area leads to a faster cooling of the melt in the initial period of the accident, but in the long term the temperatures are the same. 60 h after start of the ex-vessel phase, the melt is not stabilised.

Validation and Application of the AC2 Code COCOSYS

The GRS program package AC2 with its codes ATHLET/ATHLET-CD and COCOSYS aims for the reliable computational simulation of significant phenomena occurring during normal operation, design basis accidents, and severe accidents in the cooling circuit and containment of a nuclear power plant. To keep the modelling at the state-of-the-art, continuous development and validation is required. This is accomplished through participation in several national and international experimental research programs, where AC2 or one of its codes are assessed against both separate effect tests and integral tests. This paper exemplifies the status of validation and application of COCOSYS by means of calculations of iodine chemistry and molten corium/concrete interaction after reactor pressure vessel rupture. Further, calculations using the external 3D module CoPool coupled to COCOSYS on thermal stratification in large water pools are discussed. The examples given demonstrate the progress of the COCOSYS development and the capability to simulate phenomena in the containment during incidents and accidents with good results. Future applications comprise the entire spectrum of incidents and accidents for Generation III/III+ systems with just one program package.

[Speech processor upgrade increases speech comprehension in patients with cochlear implants]

BACKGROUND

Hearing rehabilitation of patients with severe hearing loss by cochlear implant (CI) enhances their opportunities for communication immensely with regard to their normal-hearing social environment. The degree of participation depends decisively on speech discrimination. This study examines whether speech discrimination can be improved by equipping patients with next-generation speech processors (SP).

METHODS

The changes in speech discrimination of 420 CI patients upon receiving a newer SP from 2003-2012 were retrospectively analyzed. Audiometry comprised the Freiburg number and monosyllable tests and the Oldenburg sentence test in quiet and noise, with a presentation volume of 70 dB.

RESULTS

In all audiometric tests, the newer SP showed a significant improvement compared to the preceding SP. This improvement was attainable for the majority of patients and was independent of age.

CONCLUSION

Upgrade of the SP results in improved speech discrimination. This holds true for several test settings. We therefore recommend earlier upgrades and that the costs for new SP be met.

[Treatment and auditory rehabilitation of intralabyrinthine schwannoma by means of cochlear implants - German Version]

BACKGROUND

To date, the therapy of intralabyrinthine schwannoma consists mainly of a wait-and-see approach, completely ignoring auditory rehabilitation. Only a few single-case reports are as yet available on treatment with cochlear implants (CI).

AIM OF THE STUDY

This study aimed to assess the results of auditory rehabilitation after treatment with CI in a series of cases.

MATERIALS AND METHODS

The demographic findings, symptoms, and results of surgical therapy in 8 patients were evaluated in a retrospective analysis.

RESULTS

Prior to surgery, all patients presented with profound hearing loss and tinnitus. Episodic dizziness was reported by 3 patients. Among the patients, 4 had an intracochlear and 3 an intravestibular schwannoma, and a transmodiolar schwannoma was found in 1 patient. A total of 6 patients underwent treatment with CI. The results of auditory rehabilitation are favorable with open-set speech comprehension.

DISCUSSION

CI treatment following resection of an intralabyrinthine schwannoma is a promising option for auditory rehabilitation, even in single-sided deafness. This is a new treatment concept in contrast to the wait-and-scan policy. Expectant management appears justified only if the patient still has usable hearing.

[Plasma medicine in dermatology: Mechanisms of action and clinical applications]

Plasma medicine has developed into an innovative field of research showing high potential. Since the establishment of cold atmospheric plasma, new, multifaceted medical treatment opportunities have become available. Within a short time a multidisciplinary special interest group of medical scientists, physicists, and biologists was created, aiming to understand plasma medicine and answer clinical as well as scientific questions. In dermatology, new horizons are being opened for wound healing, tissue regeneration, treatment of skin infections, and tumor therapy. A major task will be the introduction of plasma into clinical medicine and, simultaneously, the further investigation of the mechanisms of action of plasma at the cellular level. Only then can the safety of plasma treatment in patients be assured.

Interaural stimulation timing in single sided deaf cochlear implant users

The interaural time difference (ITD) is an important cue for the localization of sounds. ITD changes as little as 10 μs can be detected by the human auditory system. By provision of one ear with a cochlear implant (CI) ITD are altered due to the partial replacement of the peripheral auditory system. A hearing aid (HA), in contrast, does not replace but adds a processing delay component to the peripheral auditory system extending ITD. The aim of the present study was to quantify interaural stimulation timing between these different modalities to estimate the need for central auditory temporal compensation in single sided deaf CI users or bimodal CI/HA users. For this purpose, wave V latencies of auditory brainstem responses evoked either acoustically (ABR) or electrically via the CI (EABR) have been measured. The sum of delays consisting of CI signal processing measured in the MED-EL OPUS2 audio processor and EABR wave V latencies evoked on different intracochlear sites allowed an estimation of the entire CI channel-specific delay for MED-EL MAESTRO CI systems. We compared these values with ABR wave V latencies measured in the contralateral normal hearing or HA provided ear in different frequency bands. The results showed that EABR wave V latencies were consistently shorter than those evoked acoustically in the unaided normal hearing ear. Thus, artificial delays within the audio processor can be implemented to adjust interaural stimulation timing. The currently implemented group delays in the MED-EL CI system turned out to be reasonably similar to those of the unaided ear. For adjustment of CI and contralateral HA, in contrast, an adjustable additional across-frequency delay in the range of 1-11 ms implemented in the CI would be required. Especially for bimodal CI/HA users the adjustment of interaural stimulation timing may induce improved binaural hearing, reduced need for central auditory temporal compensation and increased acceptance of the CI/HA provision.

Feasibility study of the Mn–Na2WO4/SiO2 catalytic system for the oxidative coupling of methane in a fluidized-bed reactor

The catalytic system Mn–Na₂WO₄/SiO₂, was studied in a miniplant fluidized-bed reactor for oxidative coupling of methane.

Magnet dislocation: an increasing and serious complication following MRI in patients with cochlear implants

PURPOSE

Cochlear implantation (CI) represents the gold standard in the treatment of children born deaf and postlingually deafened adults. Initial magnetic resonance imaging (MRI) was contraindicated in CI users. Meanwhile, there are specific recommendations concerning MRI compatibility depending on the type of CI system and the device manufacturer. Some CI systems are even approved for MRI with the internal magnet left in place. The aim of this study was to analyze all magnet revision surgeries in CI patients at one CI center and the relationship to MRI scans over time.

MATERIALS AND METHODS

Between 2000 and 2013, a total of 2027 CIs were implanted. The number of magnet dislocation (MD) surgeries and their causes was assessed retrospectively.

RESULTS

In total 12 cases of MD resulting from an MRI scan (0.59 %) were observed, accounting for 52.2 % of all magnetic revision surgeries. As per the labeling, it was considered safe to leave the internal magnet in place during MRI while following specific manufacturer recommendations: MRI intensity of 1.5 Tesla (T) and compression head bandage during examination.

CONCLUSION

A compression head bandage in a 1.5 T MRI unit does not safely prevent MD and the related serious complications in CI recipients. We recommend a Stenvers view radiograph after MRI with the internal magnet in place for early identification of MD, at least in the case of pain during or after MRI examination. MRI in CI patients should be indicated with restraint and patients should be explicitly informed about the possible risks. Recommendations regarding MRI compatibility and the handling of CI patients issued with MRI for the most common CI systems are summarized.

Enhanced catalytic performance of MnxOy–Na2WO4/SiO2 for the oxidative coupling of methane using an ordered mesoporous silica support

The oxidative coupling of methane is a highly promising reaction for its direct conversion.

Enhancement of skin radical scavenging activity and stratum corneum lipids after the application of a hyperforin-rich cream

Hyperforin is well-known for its anti-inflammatory, anti-tumor, anti-bacterial, and antioxidant properties. The application of a hyperforin-rich verum cream could strengthen the skin barrier function by reducing radical formation and stabilizing stratum corneum lipids. Here, it was investigated whether topical treatment with a hyperforin-rich cream increases the radical protection of the skin during VIS/NIR irradiation. Skin lipid profile was investigated applying HPTLC on skin lipid extracts. Furthermore, the absorption- and scattering coefficients, which influence radical formation, were determined. 11 volunteers were included in this study. After a single cream application, VIS/NIR-induced radical formation could be completely inhibited by both verum and placebo showing an immediate protection. After an application period of 4weeks, radical formation could be significantly reduced by 45% following placebo application and 78% after verum application showing a long-term protection. Furthermore, the skin lipids in both verum and placebo groups increased directly after a single cream application but only significantly for ceramide [AP], [NP1], and squalene. After long-term cream application, concentration of cholesterol and the ceramides increased, but no significance was observed. These results indicate that regular application of the hyperforin-rich cream can reduce radical formation and can stabilize skin lipids, which are responsible for the barrier function.

[Implications of nutritional status for onset and characteristics of experimental acute pancreatitis in a mouse model]

BACKGROUND

Due to uncontrolled activation of digestive enzymes produced within the pancreas, acute pancreatitis is a disease with a great potential for complications and variable course. Since the pathophysiological steps of human pancreatitis can only be inadequately investigated, various animal models were established to study the course of disease. The model of supramaximal caerulein stimulation allows to gain insights into intracellular events of the early phase of acute pancreatitis. Usually, overnight fasted animals are used for the model of acute pancreatitis to achieve a maximum zymogen granula accumulation and a standardised initial situation due to diminished secretion of CCK. Furthermore, the role of the nutritional state for pathogenesis and course of acute pancreatitis is controversially discussed. The aim of the study was to investigate the impact of the nutritional status on pancreatic injury in experimental acute pancreatitis.

METHODS

Using standardised supramaximal caerulein stimulation (dose: 50 µg/kg; time intervals, 1/h; max. 7×), acute oedematous interstitial pancreatitis in fasted and non-fasted mice was induced. Pancreatic injury was locally characterised by pancreatic oedema, histopathological alterations and the release of pancreatic enzyme to the serum while systemic alterations were objectified by IL-6, CRP und pulmonal MPO.

RESULTS

1) Increased pancreatic serum enzyme levels after induction of acute pancreatitis in non-fasted animals do not reflect a greater affection of the pancreas since amylase and lipase in serum and pancreatic tissue correlate proportionally. The induction of acute pancreatitis provoked release of 1.3 % and 0.7 % of amylase and lipase, respectively, independently of nutritional status. 2) Neither local nor systemic parameters of pancreatic injury were significantly altered by the nutritional regimen. Pathohistologic investigations revealed increase of zymogen granula portion and cell size in non-fasted mice but no further differences compared with fasted animals. 3) During a 16-hour recovery period (no further caerulein injection), local and systemic parameters normalised.

DISCUSSION

In the relatively mild model of pancreatitis induced by hormonal hyperstimulation, there was no greater pancreatic injury despite higher intrapancreatic enzyme accumulation in non-fasted animals indicating a steady state between potentially damaging and protective factors and mechanisms.