Online training for hearing implant surgery : A new approach to otological training.

OBJECTIVE: Education in microsurgery of the ear includes staged training to allow for mastering of the complex microsurgical procedures, particularly in the context of middle ear reconstruction and cochlear implantation. Traditional surgical training includes temporal bone preparations by cadaver dissection and supervised operating room practice. As these on-site trainings are limited, there is a need to broaden education facilities in an on-line format. Therefore, a first basic on-line training for otosurgery was developed. MATERIALS AND METHODS: The system consists of an artificial temporal bone model together with a set of basic surgical instruments and implant dummies. As an essential part of the training kit, a high-resolution camera set is included that allows for connection to a video streaming platform and enables remote supervision of the trainees' surgical steps by experienced otological surgeons. In addition, a pre-learning platform covering temporal bone anatomy and instrumentation and pre-recorded lectures and instructional videos has been developed to allow trainees to review and reinforce their understanding before hands-on practice. RESULTS: Over the three courses held to date, 28 participants with varying levels of prior surgical experience took part in this otological surgical training program. The immediate feedback of the participants was evaluated by means of a questionnaire. On this basis, the high value of the program became apparent and specific areas could by identified where further refinements could lead to an even more robust training experience. CONCLUSION: The presented program of an otosurgical online training allows for basal education in practical exercises on a remote system. In this way, trainees who have no direct access to on-site instruction facilities in ear surgery now have the chance to start their otosurgical training in an educational setting adapted to modern technologies.

Holistic assessment of cochlear implant outcomes using the international classification of functioning disability and health model: data analysis of a longitudinal prospective multicenter study.

PURPOSE: To study outcome after cochlear implantation using the Cochlear Implant (CI) outcome assessment protocol based on the International Classification of Functioning, Disability and Health (ICF) model (CI-ICF). METHODS: Raw data of a prospective, longitudinal, multicenter study was analyzed. Seventy-two CI candidates were assessed preoperatively and six months postoperatively using the CI-ICF protocol. Following tools were used: (1) Work Rehabilitation Questionnaire (WORQ), (2) Abbreviated Profile of Hearing Aid Benefit (APHAB), (3) Audio Processor Satisfaction Questionnaire (APSQ), (4) Speech, Spatial, and Qualities of Hearing Scale (SSQ12), (5) Hearing Implant Sound Quality Index (HISQUI19), (6) Nijmegen CI Questionnaire (NCIQ) (7) pure tone audiometry, (8) speech audiometry, (9) sound localization. RESULTS: There was a significant improvement of speech discrimination in quiet (p = 0.015; p < 0.001) and in noise (p = 0.041; p < 0.001), sound detection (p < 0.001), tinnitus (p = 0.026), listening (p < 0.001), communicating with-receiving-spoken messages (p < 0.001), conversation (p < 0.001), family relationships (p < 0.001), community life (p = 0.019), NCIQ total score and all subdomain scores (p < 0.001). Subjective sound localization significantly improved (p < 0.001), while psychometric sound localization did not. There was no significant subjective deterioration of vestibular functioning and no substantial change in sound aversiveness. CI users reported a high level of implant satisfaction postoperatively. CONCLUSION: This study highlights the positive impact of cochlear implantation on auditory performance, communication, and subjective well-being. The CI-ICF protocol provides a holistic and comprehensive view of the evolution of CI outcomes.

[Comprehensive literature review on the application of the otological-surgical planning software OTOPLAN® for cochlear implantation. German version]. / Umfassender Literaturüberblick über die Anwendung der otologisch-chirurgischen Planungssoftware OTOPLAN® bei der Cochleaimplantation.

BACKGROUND: The size of the human cochlear, measured by the diameter of the basal turn, varies between 7 and 11 mm. For hearing rehabilitation with cochlear implants (CI), the size of the cochlear influences the individual frequency map and the choice of electrode length. OTOPLAN® (CAScination AG [Bern, Switzerland] in cooperation with MED-EL [Innsbruck, Austria]) is a software tool with CE marking for clinical applications in CI treatment which allows for precise pre-planning based on cochlear size. This literature review aims to analyze all published data on the application of OTOPLAN®. MATERIALS AND METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were applied to identify relevant studies published in the PubMed search engine between January 2015 and February 2023 using the search terms "otoplan" [title/abstract] OR "anatomy-based fitting" [title/abstract] OR "otological software tool" [title/abstract] OR "computed tomography-based software AND cochlear" [title/abstract]. RESULTS: The systematic review of the literature identified 32 studies on clinical use of OTOPLAN® in CI treatment. Most studies were reported from Germany (7 out of 32), followed by Italy (5), Saudi Arabia (4), the USA (4), and Belgium (3); 2 studies each were from Austria and China, and 1 study from France, India, Norway, South Korea, and Switzerland. In the majority of studies (22), OTOPLAN® was used to assess cochlear size, followed by visualizing the electrode position using postoperative images (5), three-dimensional segmentation of temporal bone structures (4), planning the electrode insertion trajectory (3), creating a patient-specific frequency map (3), planning of a safe drilling path through the facial recess (3), and measuring of temporal bone structures (1). CONCLUSION: To date, OTOPLAN® is the only DICOM viewer with CE marking in the CI field that can process pre-, intra-, and postoperative images in the abovementioned applications.

Development of an algorithm for correct placement of the basal electrode contact in the context of anatomy based cochlear implantation: a proof of concept.

BACKGROUND: Correct individual tonotopic frequency stimulation of the cochlea plays an important role in the further development of anatomy based cochlear implantation. In this context frequency specific fitting of the basal electrode contact with a normal insertion depth can be difficult since it is often placed in a frequency range higher than 10 kHz and current audio processors only stimulate for frequencies up to 8.5 kHz due to microphone characteristics. This results in a mismatch of the high frequencies. Therefore, this study represents a proof of concept for a tonotopic correct insertion and aims to develop an algorithm for a placement of the basal electrode below 8.5 kHz in an experimental setting. METHODS: Pre- and postoperative flat-panel volume CT scans with secondary reconstructions were performed in 10 human temporal bone specimens. The desired frequency location for the most basal electrode contact was set at 8.25 kHz. The distance from the round window to the position where the basal electrode contact was intended to be located was calculated preoperatively using 3D-curved multiplanar reconstruction and a newly developed mathematical approach. A specially designed cochlear implant electrode array with customized markers imprinted on the silicone of the electrode array was inserted in all specimens based on the individually calculated insertion depths. All postoperative measurements were additionally validated using an otological planning software. RESULTS: Positioning of the basal electrode contact was reached with only a small mean deviation of 37 ± 399 Hz and 0.06 ± 0.37 mm from the planned frequency of 8.25 kHz. The mean rotation angle up to the basal electrode contact was 51 ± 5 °. In addition, the inserted electrode array adequately covered the apical regions of the cochleae. CONCLUSION: Using this algorithm, it was possible to position the basal electrode array contact in an area of the cochlea that could be correctly stimulated by the existing speech processors in the context of tonotopic correct fitting.

[Online training for hearing implant surgery : A new approach to otological training. German version]. / Online-Training für Hörimplantatchirurgie : Ein neuer Ansatz in der otologischen Ausbildung.

OBJECTIVE: Education in microsurgery of the ear includes staged training to allow for mastering of the complex microsurgical procedures, particularly in the context of middle ear reconstruction and cochlear implantation. Traditional surgical training includes temporal bone preparations by cadaver dissection and supervised operating room practice. As these on-site trainings are limited, there is a need to broaden education facilities in an on-line format. Therefore, a first basic on-line training for otosurgery was developed. MATERIALS AND METHODS: The system consists of an artificial temporal bone model together with a set of basic surgical instruments and implant dummies. As an essential part of the training kit, a high-resolution camera set is included that allows for connection to a video streaming platform and enables remote supervision of the trainees' surgical steps by experienced otological surgeons. In addition, a pre-learning platform covering temporal bone anatomy and instrumentation and pre-recorded lectures and instructional videos has been developed to allow trainees to review and reinforce their understanding before hands-on practice. RESULTS: Over the three courses held to date, 28 participants with varying levels of prior surgical experience took part in this otological surgical training program. The immediate feedback of the participants was evaluated by means of a questionnaire. On this basis, the high value of the program became apparent and specific areas could by identified where further refinements could lead to an even more robust training experience. CONCLUSION: The presented program of an otosurgical online training allows for basal education in practical exercises on a remote system. In this way, trainees who have no direct access to on-site instruction facilities in ear surgery now have the chance to start their otosurgical training in an educational setting adapted to modern technologies.

A Retrospective Analysis of Temporal Lobe Gliosis after Middle Fossa Resection of Small Vestibular Schwannomas.

INTRODUCTION: The middle cranial fossa (MCF) approach is a well-established procedure in surgery of the internal auditory canal, as well as with the retrosigmoid and translabyrinthine approaches. It is commonly used in the hearing-preserving microsurgery of small vestibular schwannomas (VS). The debate about the "best" approach for the microsurgery of small VS without contact to the brainstem is controversial. It has been stated that the MCF approach leads to irreversible damage to the temporal lobe, which may be evident in follow-up magnet resonance imaging (MRI) as gliosis in up to 70% of patients. MATERIALS AND METHODS: This study represents a retrospective chart analysis conducted at a tertiary university hospital. Here, 76 postoperative MRIs were re-evaluated by an experienced neuroradiologist and compared with the preoperative images. Temporal lobe gliosis was classified on an ordinal scale as absent, slight, moderate or severe. Occurrence of gliosis was matched to the clinical predictors (tumor stage, tumor volume, sex, age, and side). RESULTS: No case of severe or moderate gliosis was found in the patient group. Slight gliosis of the temporal lobe was rare and was only detected in four patients (5%). There was no relation between clinical predictors and the incidence of gliosis. CONCLUSIONS: In our cohort, postoperative MR imaging did not reveal relevant damage to the temporal lobe parenchyma. This confirms the safe concept of microsurgery of small tumors via the middle fossa approach. The severe glioses described in other studies may be caused by a forced insertion of the retractor or by more extended approaches. However, further prospective neurocognitive studies seem to be necessary in order to assess functional changes in the temporal lobe.

[Initial assessment of ENT emergencies-a feasibility study]. / Ersteinschätzung HNO-spezifischer Notfälle ­ eine Machbarkeitsstudie.

In Germany, an increased volume of patient cases in the emergency department has been observed for several years, many of which do not represent hospital emergencies. To improve the triage and management of patient flows, the Structured Initial Medical Assessment (Strukturierte medizinische Ersteinschätzung in Deutschland, SmED) triage system was developed. This certified medical product is intended to assess both the urgency of everyday complaints and their adequate medical care in a targeted, faster, and safer manner. It supports medical professionals in triage by suggesting courses of action, whereby the ultimate responsibility remains with the professionals themselves. For otorhinolaryngology, a content review was carried out with regard to plausibility and patient safety in the head and neck region on the basis of nine specific emergencies. The cases were simulated by nine otorhinolaryngologists and triaged on the basis of the SmED by medical staff and medical students by assigning a care level and timepoint (urgency). The majority of cases were correctly assigned. The SmED initial assessment system is a good tool for assessing urgent clinical pictures in ear, nose, and throat (ENT) medicine. The long-term goal of the initial assessment is to relieve the capacities of outpatient departments. In order to achieve this and to shorten patient waiting times, it would be necessary to refer patients quickly to otorhinolaryngology. It is therefore necessary to ensure that patients are referred to an ENT on-call service via the online tool.

[Repetitio est mater studiorum-implementation of ENT cases in case-based e-learning]. / Repetitio est mater studiorum ­ Implementierung von HNO-Fällen in fallbasiertes E-Learning.

BACKGROUND: German university otorhinolaryngology has a need for digital teaching content. Case-based e­learning represents a digital teaching methodology. The data on student use of case-based e­learning in university teaching of ENT medicine are limited. OBJECTIVE: The aim of this work was to determine the extent to which voluntary case-based e­learning is used by otolaryngology students and what influence the quality of the e­learning has on motivation to use e­learning and on the interest in otolaryngology. MATERIALS AND METHODS: Fifteen voluntary e­learning cases were created based on the content of the ENT lecture in the winter semester 2022/2023. Subsequently, a descriptive evaluation of the usage statistics of the cases of 157 students was conducted. Likewise, an evaluation of the quality of the e­learning as well as the motivation to complete it and the interest in otorhinolaryngology was carried out using a voluntary questionnaire. RESULTS: Voluntary case-based e­learning was used to varying degrees by 66% of the students. The quality of e­learning correlated significantly with the motivation and the interest in otolaryngology. CONCLUSION: The teaching content of otorhinolaryngology can be implemented sufficiently in case-based e­learning and is characterized by satisfactory student acceptance. Integration should be accomplished in a high-quality manner to increase motivation and interest in otorhinolaryngology.

Dependence of Cochlear Duct Length Measurement on the Resolution of the Imaging Dataset.

HYPOTHESIS: Measurements of the cochlear duct length (CDL) are dependent on the resolution of the imaging dataset. BACKGROUND: Previous research has shown highly precise cochlear measurements using 3D-curved multiplanar reconstruction (MPR) and flat-panel volume computed tomography (fpVCT). Thus far, however, there has been no systematic evaluation of the imaging dataset resolution required for optimal CDL measurement. Therefore, the aim of this study was to evaluate the dependence of CDL measurement on the resolution of the imaging dataset to establish a benchmark for future CDL measurements. METHODS: fpVCT scans of 10 human petrous bone specimens were performed. CDL was measured using 3D-curved MPR with secondary reconstruction of the fpVCT scans (fpVCT SECO ) and increasing resolution from 466 to 99 µm. In addition, intraobserver variability was evaluated. A best-fit function for calculation of the CDL was developed to provide a valid tool when there are no measurements done with high-resolution imaging datasets. RESULTS: Comparison of different imaging resolution settings showed significant differences for CDL measurement in most of the tested groups ( p < 0.05), except for the two groups with the highest resolution. Imaging datasets with a resolution lower than 200 µm showed lower intraobserver variability than the other resolution settings, although there were no clinically unacceptable errors with respect to the Bland-Altman plots. The developed best-fit function showed high accuracy for CDL calculation using resolution imaging datasets of 300 µm or lower. CONCLUSION: 3D-curved MPR in fpVCT with a resolution of the imaging dataset of 200 µm or higher revealed the most precise CDL measurement. There was no benefit of using a resolution higher than 200 µm with regard to the accuracy of the CDL measurement.

Comparison of three different image enhancement systems for detection of laryngeal lesions.

OBJECTIVE: Image enhancement systems are important diagnostic tools in the detection of laryngeal pathologies. This study aimed to compare three different image enhancement systems: professional image enhancement technology, Image1 S and narrow-band imaging. METHOD: Using the three systems, 100 patients with laryngeal lesions were investigated using a flexible and a 30° rigid endoscope. The lesions were diagnosed by three experts and classified using the Ni classification. The findings were compared. RESULTS: Lesions classified as 'benign' were histopathologically confirmed in 50 per cent of patients, malignant lesions were confirmed in 41 per cent and recurrent respiratory papillomatosis were confirmed in 9 per cent. There was no significant difference between the experts' assessments of each image enhancement system. CONCLUSION: The three systems give comparable results in the detection of laryngeal lesions. With two additional systems, more users can perform image-enhanced endoscopy, resulting in a broadly available tool that can help to improve oncological assessment.

Do Disinfectant Solutions during Gargling Reach the Pharynx?

INTRODUCTION: In times of COVID-19, gargling disinfectant is commonly used. Disinfectant solutions seem to decrease the infection's symptoms. For disinfection, several techniques are reported. So far, there are no data about the regions in the upper airways achieved by gargled fluid. METHODS: Ten healthy volunteers without any dysphagia were investigated with a high-sensitivity flexible endoscopic evaluation of swallowing (hsFEES®) during and after gargling colored water. One volunteer repeated the gargling process in fast and real-time MRI. RESULTS: In all cases, no color accumulation was detected on the posterior pharyngeal wall, epi- or hypopharynx during gargling. The MRI scans confirmed the results. CONCLUSIONS: hsFEES® and fast MRI provide an insight into the gargling pattern. Data show that during gargling, the fluid covers the soft tissue in the oral cavity and the anterior part of the soft palate, but not the posterior pharyngeal wall nor the epi- and hypopharynx.

[18F]FDG PET/CT can trigger relevant oncological management changes leading to favorable outcome in iodine-negative thyroid cancer patients.

BACKGROUND: In patients with iodine-negative thyroid cancer (TC), current guidelines endorse an [18F]FDG PET/CT to identify dedifferentiated sites of disease. We aimed to determine the rate of oncological management changes triggered by such a molecular imaging approach, along with the impact on outcome. METHODS: 42 consecutive patients with negative findings on [131I] whole body scan were scheduled for [18F]FDG PET/CT and treatment based on PET results were initiated. To determine the impact on oncological management, we compared the therapeutic plan prior to and after molecular imaging. Based on imaging follow-up, the rate of controlled disease (CD, defined as stable disease, complete or partial response) was also recorded, thereby allowing to assess whether [18F]FDG-triggered management changes can also lead to favorable outcome. RESULTS: We observed no alterations of the treatment plan in 9/42 (21.4%) subjects (active surveillance in 9/9 [100%]). Oncological management was changed in the remaining 33/42 (78.6%; systemic treatment in 9/33 [27.3%] and non-systemic treatment in 24/33 [72.7%]). Among patients receiving non-systemic therapy, the following changes were noted: surgery in 20/24 (83.3%) and radiation therapy in 4/24 (16.7%). In the systemic group, tyrosine kinase inhibitor (TKI) was prescribed in 8/9 (88.9%), while radioiodine therapy based on a TKI-mediated redifferentiation approach was conducted in 1/9 (11.1%). In 26 subjects with available follow-up, rate of CD was 22/26 (84.6%) and among those, 15/22 (68.1%) had experienced previous management changes based on PET/CT findings. CONCLUSIONS: In subjects with iodine-negative TC, [18F]FDG PET/CT triggered relevant management changes along with disease control in the vast majority of patients. As such, in dedifferentiated TC, [18F]FDG PET/CT may serve as a relevant management tool and therapeutic decision-aid in the clinic.

The Stapes Head Coupler-A Flexible and Safe Option for Vibroplasty.

OBJECTIVE: To investigate the surgical approach and the audiological outcome of a stapes head coupler in active middle ear implant surgery. STUDY DESIGN: Retrospective data analysis. SETTING: Tertiary referral center with a large active middle ear implant program. PATIENTS: Twelve patients with active middle ear implant surgery. INTERVENTIONS: Therapeutic surgical approach for hearing rehabilitation in human subjects. MAIN OUTCOME MEASURES: Auditory brainstem response, sound field thresholds, vibrogram, speech perception in the Freiburger monosyllabic word test. RESULTS: The stapes head was attached safely in different coupling situations. Audiological outcomes were similar to the audiological performance of established vibroplasty couplers presented in the literature. CONCLUSION: The stapes head coupler is a new and safe tool for vibroplasty with a good audiological outcome.

Computed tomographic 3D analysis of the cochlear aqueduct-potential and limitations of clinical imaging.

Background: The cochlear aqueduct (CA), which connects the scala tympani and the subarachnoid space, and its accompanying structures appear to have a significant relevance during cochlear implantation and an accurate visualization in clinical imaging is of great interest. Aims and Objective: This study aims to determine which potential and limitations clinically available imaging modalities have in the visualization of the CA. Methods: Micro-CT, flat-panel volume computed tomography with and without secondary reconstruction (fpVCT, fpVCTseco) and multislice computed tomography (MSCT) of 10 temporal bone specimen were used for 3D analysis of the CA. Results: FpVCTseco proved superior in visualizing the associated structures and lateral portions of the CA, which merge into the basal turn of the cochlea. All clinical imaging modalities proved equal in analyzing the length, total volume of the CA and its area of the medial orifice. Conclusion: The choice of the most accurate clinical imaging modality to evaluate the CA and its associated structures depends on the clinical or scientific question. Furthermore, this study should provide a basis for further investigations analyzing the CA.

Diagnostic efficacy of C-X-C motif chemokine receptor 4-directed PET/CT in newly diagnosed head and neck squamous cell carcinoma - a head-to-head comparison with [18F]FDG.

BACKGROUND: The aim of this study was to determine the read-out capabilities of the novel C-X-C motif chemokine receptor 4 (CXCR4)-targeting radiotracer [68Ga]Ga-PentixaFor compared to the reference radiotracer [18F]FDG in untreated individuals with head and neck squamous cell carcinoma (HNSCC). MATERIAL AND METHODS: 12 patients with histologically confirmed HNSCC were scheduled for [18F]FDG and [68Ga]Ga-PentixaFor PET/CT. Maximum standardized uptake values (SUVmax) and target-to-background ratios (TBR) were applied with vena cava superior serving as reference. In addition, we compared [68Ga]Ga-PentixaFor-PET findings with immunohistochemical (IHC) results of CXCR4 expression. RESULTS: On visual assessment, [18F]FDG identified more sites of disease, with increased detection rates for both the primary tumor ([18F]FDG, 12/12 [100%] vs. [68Ga]Ga-PentixaFor, 10/12 [83%]) and LN metastases ([18F]FDG, 9/12 [75%] vs. [68Ga]Ga-PentixaFor, 8/12 [67%]). Indicative for improved image contrast using [18F]FDG, quantification showed a higher TBR for the latter radiotracer, when compared to [68Ga]Ga-PentixaFor for all lesions ([18F]FDG, 11.7 ± 8.5 vs. [68Ga]Ga-PentixaFor, 4.3 ± 1.3; P=0.03), primary tumors ([18F]FDG, 13.6 ± 8.7 vs. [68Ga]Ga-PentixaFor, 4.4 ± 1.4; P<0.01), and LN lesions ([18F]FDG, 9.3 ± 10.6 vs. [68Ga]Ga-PentixaFor, 4.7 ± 1.5; P=0.3). IHC showed variable CXCR4 expression in the primary and LN, along with no associations between ex-vivo CXCR4 upregulation and [68Ga]Ga-PentixaFor-based TBR (R=0.33, P=0.39) or SUVmax (R=0.44, P=0.2). Of note, IHC also revealed heterogeneous expression of CXCR4 in immune cells in the tumor microenvironment and in germinal centers, indicative for inflammatory reactions. CONCLUSIONS: In HNSCC, [18F]FDG demonstrated superior diagnostic performance relative to [68Ga]Ga-PentixaFor, in particular for assessment of the primary. Based on the IHC analyses, these findings may be explained by CXCR4 upregulation not only by tumor but also by immune cells in the tumor microenvironment.

Ag- but Not ZnO-Nanoparticles Disturb the Airway Epithelial Barrier at Subtoxic Concentrations.

Inhalation is considered to be the most relevant source of human exposure to nanoparticles (NPs); however, only a few investigations have addressed the influence of exposing the respiratory mucosal barrier to subcytotoxic doses. In the nasal respiratory epithelium, cells of the mucosa represent one of the first contact points of the human organism with airborne NPs. Disruption of the epithelial barrier by harmful materials can lead to inflammation in addition to potential intrinsic toxicity of the particles. The aim of this study was to investigate whether subtoxic concentrations of zinc oxide (ZnO)- and silver (Ag)-NPs have an influence on upper airway barrier integrity. Nasal epithelial cells from 17 donors were cultured at the air-liquid interface and exposed to ZnO- and Ag-NPs. Barrier function, quantified by transepithelial electrical resistance (TEER), decreased after treatment with 10 µg/mL Ag-NPs, but FITC-dextran permeability remained stable and no change in mRNA levels of tight junction proteins and E-cadherin was detected by real-time quantitative PCR (RT-qPCR). The results indicate that subtoxic concentrations of Ag-NPs may already induce damage of the upper airway epithelial barrier in vitro. The lack of similar disruption by ZnO-NPs of similar size suggests a specific effect by Ag-NPs.

Discontinuation of anti­programmed cell death protein 1 immune checkpoint inhibition after complete remission in head and neck squamous cell carcinoma: A case report and literature review.

Programmed cell death protein 1 (PD-1) inhibition plays a central role in the current treatment of recurrent or metastatic head and neck squamous cell carcinoma (R/M-HNSCC). Some patients achieve a durable response, and even complete remission (CR) is possible, though it occurs rarely. In cases of durable CR, there are no guidelines regarding a possible discontinuation of immunotherapy. Since clinical experience on this issue is limited, the present study reported on a case of a durable CR following discontinuation of PD-1 inhibition in R/M-HNSCC and additionally presented an overview on the current literature. The present study reported on a case of CR of recurrent oropharyngeal cancer after four cycles of PD-1 monotherapy with Nivolumab. The therapy was discontinued after overall 46 cycles. Even after 3 more years of follow-up, there was no sign of tumor recurrence. Overall, according to reports from the literature, CR seems to be an indicator for durable disease control after therapy discontinuation. Since data on therapy termination is rare, decisions about when to stop successful immunotherapy in R/M-HNSCC have to be made individually for each patient.

Somatostatin Receptor-Directed PET/CT Can Differentiate Between Different Subtypes of Head and Neck Paragangliomas.

BACKGROUND: Given their neuroendocrine origin, head and neck paragangliomas (HNPGLs) can be imaged with somatostatin receptor (SSTR)-directed PET/CT. We aimed to determine whether the in vivo PET signal can differentiate between varying HNPGL subtypes. PATIENTS AND METHODS: Fourteen patients with HNPGL received pretherapeutic SSTR-PET/CTs using 68 Ga-DOTATOC. Six (42.9%) patients had a jugular paraganglioma (PGL-J), 5 (35.7%) were diagnosed with carotid paraganglioma (PGL-Cs), and the remaining 3 patients (21.4%) had PGL-C with pathogenic SDHx germline variants (PGL-C-SDH). A visual and quantitative assessment of the primary tumor on SSTR-PET was performed, including SUV max and target-to-background ratio (TBR). Quantitative values were then compared between subgroups of patients affected with different HNPGL entities. RESULTS: On visual assessment, all primary HNPGLs could be identified on SSTR-PET/CT. Quantification of HNPGL revealed substantially elevated SUV max in PGL-J (101.7 ± 58.5) when compared with PGL-C-SDH (13.4 ± 5.6, P < 0.05), but not when compared with PGL-C (66.7 ± 27.3, P = 0.4; PGL-C vs PGL-C-SDH, P = 0.2). TBR of PGL-J (202.9 ± 82.2), however, further differentiated between PGL-C (95.7 ± 45.4, P < 0.05) and PGL-C-SDH (20.4 ± 12.2, P < 0.01; PGL-C vs PGL-C-SDH, P = 0.3). Moreover, whole-body readout revealed metastases in 2/3 (66.7%) of PGL-C-SDH patients, with a single SSTR-expressing skeletal lesion in one subject and bipulmonary lesions in the other patient. CONCLUSIONS: In patients with HNPGL, SSTR-PET/CT identified the primary and metastatic disease and provides substantially elevated TBR, indicating excellent image contrast. PET-based quantification can also differentiate between varying HNPGL subtypes.

mRNA Abundance of Neurogenic Factors Correlates with Hearing Capacity in Auditory Brainstem Nuclei of the Rat.

Neural stem cells (NSCs) have previously been described up to the adult stage in the rat cochlear nucleus (CN). A decreasing neurogenic potential was observed with critical changes around hearing onset. A better understanding of molecular factors affecting NSCs and neurogenesis is of interest as they represent potential targets to treat the cause of neurologically based hearing disorders. The role of genes affecting NSC development and neurogenesis in CN over time on hearing capacity has remained unclear. This study investigated the mRNA abundance of genes influencing NSCs and neurogenesis in rats' CN over time. The CN of rats on postnatal days 6, 12, and 24 were examined. Real-time quantitative polymerase chain reaction arrays were used to compare mRNA levels of 84 genes relevant to NSCs and neurogenesis. Age- and hearing-specific patterns of changes in mRNA abundance of neurogenically relevant genes were detected in the rat CN. Additionally, crucial neurogenic factors with significant and relevant influence on neurogenesis were identified. The results of this work should contribute to a better understanding of the molecular mechanisms underlying the neurogenesis of the auditory pathway.

Electrically evoked auditory responses: A classification for brainstem implant placement in Neurofibromatosis Type 2.

OBJECTIVE: In auditory brainstem implant (ABI) surgery, array placement may be optimized by electrophysiological information of adequate brainstem activation gained from electrically evoked auditory brainstem responses (EABR). This study aims 1) to characterize in detail the EABR from ABI implantation, 2) to introduce an EABR Classification Scheme, and 3) to analyze data for their correlation with individual patients' findings. METHODS: Out of a continuous series of 54 patients who received an ABI between 2005 and 2019, 23 Neurofibromatosis Type 2 patients with complete documentation of 154 recordings were selected for offline analysis and for development and evaluation of a new EABR Classification Scheme comprising Class A: three vertex positive peaks, Class B:two peaks, Class C: a combination of one peak and a second melted double peak, Class D: one sole vertex positive peak and Class E: no peaks. RESULTS: All 23 subjects showed EABR at final ABI position and experienced auditory sensations at first activation. The most frequent morphology consisted of two peaks, Classes B and C. Identified mean latencies were for P1 0.42 ms (±0.095), P2 1.42 ms (±0.244) and P3 2.41 ms (±0.329). Peak latencies correlated positively with tumor extensions (p < 0.005). CONCLUSIONS: This study provides clear instructions on optimal EABR performance and evaluation. SIGNIFICANCE: The new EABR Classification Scheme relies on a fast "online" identification of vertex positive peaks at the estimated post-artifact phase. The variability in EABR morphology provides an individual snapshot of the actual structural and functional status of the brainstem.