Objective: The aim of this study was to retrospectively investigate if there is any incidence of electrode tip fold-over with 31.5 mm long and flexible lateral wall electrodes implanted in two high-volume Cochlear Implant (CI) centers in Germany. In addition, a detailed literature review was performed to capture all the peer-reviewed publications reporting on tip fold-over with CI electrodes from different CI brands for comparison. Methods: Post-operative X-ray images of FLEX SOFT electrode from MED-EL in Stenver's view were retrospectively investigated for the presence of electrode tip fold-over from 378 consecutive cases in two high-volume CI centers in Germany. All patients were implanted between 2010 and 2018 by three individual experienced CI surgeons using round window and extended round window approach for CI electrode insertion. A literature review was performed following a thorough PubMed (https://www.ncbi.nlm.nih.gov/pubmed/) search using the keywords “cochlear implant electrode tip fold-over” or “cochlear implant electrode tip roll-over” to capture articles that were published until December 2020 in English language only. Articles selection was based on electrode-related issues investigated only in-patient cases applying imaging modality. Those studies investigated tip fold-over in cadaveric temporal bones and cases with inner-ear malformation excluded. Results: No single case of tip fold-over was clinically detected from the retrospective investigation of post-operative X-ray images from 378 consecutive cases. The electrode angular insertion depth as measured applying the cochlear coordinate system, varied from a minimum of 560° to a maximum of 720°. The literature review on the tip fold-over issue resulted in 24 peer-reviewed published articles in total. Tip fold-over with pre-curved modiolar-hugging electrodes was reported in 85 cases out of 1,606 implantations making an incidence rate of 5.3%. With the straight lateral wall electrodes, the tip fold-over was reported in four cases out of 398 implantations making an incidence rate of 1%, not including the number of implantations reported in the current study. Otherwise it would be 0.5%. Conclusion: Electrode tip fold-over with 31.5 mm long flexible lateral wall electrodes is highly exceptional and this can be generalized to any of the straight lateral wall electrodes from any CI brand. The literature review on tip fold-over revealed an incidence rate of 5.3% with pre-curved or modiolar-hugging electrodes and 1% with straight lateral wall electrodes from CI brands. Including this series of 0% tip fold-over, the incidence rate of electrode tip fold-over with LW electrode type would be 0.5%.

Despite the high correlation between sIgE levels and symptoms, no serologic parameter had a sufficiently high accuracy to distinguish between silent sensitization and clinically relevant allergy. Therefore, nasal provocation tests remain the gold-standard to investigate the clinical relevance in Dermatophagoides pteronyssinus sensitization.

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Since the beneficial implementation of allergen specific subcutaneous immunotherapy (SCIT), there are only a few studies on the risk of SCIT-induced neosensitizations. In 51 patients, we retrospectively analyzed sige and sigG patterns by a multiplex eLiSA as well as demographic and clinical features before and after SCIT. 33 allergic patients, who only received symptomatic treatment, served as controls. In 12 of 51 SCIT-treated patients (24%), we found new sIgE against allergen components of the allergen source treated by Scit; eight of them were adults. Among controls, no adult patient showed neosensitization to components of the primarily affected allergen source. Only two children of the control group were affected by neosensitization, which was limited to major allergen components and rarely accompanied by sIgG. In the SCIT-treated group, neosensitization affected major and minor allergen components, and was accompanied by a strong induction of sIgG against major components. A clear clinical predictor of neosensitization during Scit was not found. comparing symptom scores, patients seem to profit more from SCIT, if neosensitization remained absent. Patients undergoing SCIT might carry an enhanced risk of neosensitization towards formerly unrecognized allergen components. According to anamnestic data, these neosensitizations might be of clinical relevance -supporting attempts towards personalized recombinant vaccines.Since the implementation of allergen specific immunotherapy (SIT) in clinical practice, many studies have been conducted to analyze the immunological changes during SIT 1 . Many publications focus on the antibody responses induced by SIT in general and the antibody shift from IgE to IgG subclasses in particular 2 .However, there are only a few studies on the potential induction of new sensitizations by SIT. The exposure to allergens, especially if combined with adjuvants, might lead to new sensitization to formerly unrecognized allergen epitopes 3,4 . With regard to venom SIT, the neosensitization to minor allergens has been described 5 . Concerning other important allergen sources, conflicting results are found: Regarding house dust mite (HDM) and grass pollen, the percentage of de novo sensitizations toward minor allergens differ from 0% 6-10 to 8-12% 11-13 .One major influencing variable might be the observation period: Studies with short-term observation after one course of SIT or less tend to exclude neosensitization 7-10 , possibly by missing middle-or long-term immunological changes occurring only after longer period of repetitive exposure to the allergen. However, all studies reporting de novo sensitization induced by SIT had a longer observation period 12,13 except for the publication by Baron-Bodo et al. in 2013 11 detecting neosensitization in 10% of patients treated by grass pollen sublingual immunotherapy (SLIT) for four months only. With regard to de novo sensitization induced by birch pollen SIT, all three published studies report on cases of neosensitization [14][15][16] .Another ...

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