32 research outputs found
a critical look into stapedotomy learning curve influence of patient characteristics and different criteria defining success
Purpose: To evaluate stapedotomy learning curve with cumulative summation methodology using different success criteria (ie, air-bone gap [ABG] ≤10 dB, ABG ≤15 dB, restoration of interaural symmetry, or hearing threshold gain >20 dB), and to assess patient characteristics influencing or modifying the learning curve. Methods: Retrospective chart review of primary and revision stapedotomy cases performed by surgeon 1 (S1, n = 78) and surgeon 2 (S2, n = 85). Results: Using the classic criterion for a successful stapedotomy (ABG ≤10 dB), patients with preoperative ABG >34 dB were associated with unsuccessful procedures (S1 P = .02; S2 P = .07). Revision surgery was associated with unsuccessful outcomes (S1 P = .005; S2 P = .0012). Cumulative summation plots using different criteria did not show a linear trend of association between stapedotomy success and number of operations, but preoperative characteristics of the patients who underwent stapedotomy significantly influenced the plots. Cumulative summation plots showed an initial increasing tendency with improving results, but when ear surgeons got more skilled, they operated on more complex cases (ie, patients with higher preoperative ABG or revision stapedotomy) and they could not meet the success criteria. Conclusions: Cumulative summation plots do not seem useful to evaluate the stapedotomy learning curve, as they do not correctly deal with heterogeneous case series. The increasing complexity of the stapedotomy patients during the surgeons' career impacts on the outcome of stapedotomy and confounds the evaluation of the growing skills of the surgeon. Stapedotomy audiological success rates are strongly influenced by the success criteria used
Evaluation of the modified Pittsburgh classification for predicting the disease-free survival outcome of squamous cell carcinoma of the external auditory canal
Background: Squamous cell carcinoma (SCC) of the external auditory canal (EAC) is a rare disease, which is commonly classified with the modified Pittsburgh classification. Our aim was to evaluate the predictive performance of this classification in relation to disease-free survival (DFS). Methods: We examined retrospective data from a nationwide Dutch cohort study including patients with primary EAC SCC. These data were combined with individual patient data from the literature. Using the combined data, the predictive performances were calculated using the c-index. Results: A total of 381 patients were included, 294 for clinical and 281 for the pathological classification analyses. The c-indices of the clinical and the pathological modified Pittsburgh classification predicting DFS were 0.725 (0.668-0.782) and 0.729 (0.672-0.786), respectively. Conclusion: The predictive performance of the modified Pittsburgh classification system as such appears to be acceptable to predict the DFS of EAC SCC. Other factors need to be added to a future model to improve the predicted performance
Frequently asked questions about chlorophyll fluorescence, the sequel
[EN] Using chlorophyll (Chl) a fluorescence many aspects of the photosynthetic apparatus can be studied, both in vitro and, noninvasively, in vivo. Complementary techniques can help to interpret changes in the Chl a fluorescence kinetics. Kalaji et al. (Photosynth Res 122: 121-158, 2014a) addressed several questions about instruments, methods and applications based on Chl a fluorescence. Here, additionalChl a fluorescence-related topics are discussed again in a question and answer format. Examples are the effect of connectivity on photochemical quenching, the correction of F-V/F-M values for PSI fluorescence, the energy partitioning concept, the interpretation of the complementary area, probing the donor side of PSII, the assignment of bands of 77 K fluorescence emission spectra to fluorescence emitters, the relationship between prompt and delayed fluorescence, potential problems when sampling tree canopies, the use of fluorescence parameters in QTL studies, the use of Chl a fluorescence in biosensor applications and the application of neural network approaches for the analysis of fluorescence measurements. The answers draw on knowledge fromdifferent Chl a fluorescence analysis domains, yielding in several cases new insights.Kalaji, H.; Schansker, G.; Brestic, M.; Bussotti, F.; Calatayud, A.; Ferroni, L.; Goltsev, V.... (2017). Frequently asked questions about chlorophyll fluorescence, the sequel. 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Voluntary disclosure of corporate strategy: determinants and outcomes. An empirical study into the risks and payoffs of communicating corporate strategy.
Business leaders increasingly face pressure from stakeholders to be transparent. There
appears however little consensus on the risks and payoffs of disclosing vital information
such as corporate strategy. To fill this gap, this study analyzes firm-specific determinants
and organisational outcomes of voluntary disclosure of corporate strategy. Stakeholder
theory and agency theory help to understand whether companies serve their interest to
engage with stakeholders and overcome information asymmetries. I connect these
theories and propose a comprehensive approach to measure voluntary disclosure of
corporate strategy. Hypotheses from the theoretical framework are empirically tested
through panel regression of data on identified determinants and outcomes and of
disclosed strategy through annual reports, corporate social responsibility reports,
corporate websites and corporate press releases by the 70 largest publicly listed
companies in the Netherlands from 2003 through 2008. I found that industry,
profitability, dual-listing status, national ranking status and listing age have significant
effects on voluntary disclosure of corporate strategy. No significant effects are found for
size, leverage and ownership concentration. On outcomes, I found that liquidity of stock
and corporate reputation are significantly influenced by voluntary disclosure of corporate
strategy. No significant effect is found for volatility of stock. My contributions to theory,
methodology and empirics offers a stepping-stone for further research into understanding
how companies can use transparency to manage stakeholder relations
Cochlear Implantation in Adults with Asymmetric Hearing Loss: Benefits of Bimodal Stimulation
Objective: This study addresses the outcome of cochlear implantation in addition to hearing aid use in patients with asymmetric sensorineural hearing loss. Study Design: Prospective longitudinal study. Setting: Tertiary referral center. Patients: Seven adults with asymmetric sensorineural hearing loss, i.e., less than 30% aided speech recognition in their worst hearing ear and 60 to 85% speech recognition in their best hearing ear. All patients had a postlingual onset of their hearing loss and less than 20 years of auditory deprivation of their worst hearing ear. Intervention: Cochlear implantation in the functionally deaf ear. Main Outcome Measures: Speech recognition in quiet, speech recognition in noise, spatial speech recognition, localization abilities, music appreciation, and quality of life. Measurements were performed before cochlear implantation and 3, 6, and 12 months after cochlear implantation. Results: Before cochlear implantation, the average speech recognition of the ear fitted with a hearing aid was 74%. Cochlear implantation eventually resulted in an average speech recognition of 75%. Bimodal stimulation yielded speech recognition scores of 82, 86, and 88% after 3, 6, and 12 months, respectively. At all time intervals, bimodal stimulation resulted in a significantly better speech recognition as compared with stimulation with only hearing aid or only cochlear implant (CI). Speech recognition in noise and spatial speech recognition significantly improved as well as the ability to localize sounds and the quality of life. Conclusion: This study demonstrated that patients are able to successfully integrate electrical stimulation with contralateral acoustic amplification and benefit from bimodal stimulation. Therefore, we think that cochlear implantation should be considered in this particular group of patients, even in the presence of substantial residual hearing on the contralateral side
Monitoring of laryngopharyngeal reflux: Influence of meals and beverages
Ambulatory 24-hour double-probe pH monitoring seems to be the best test to measure reflux. Artifacts caused by intake of acid foods and beverages have to be excluded, necessitating a time-consuming manual review of the 24-hour data. Dietary restrictions used to bypass these artifacts would interfere with the normal daily life situation. Therefore, the influence of food and beverages ingested during the monitoring period was studied. Data from 252 patients who underwent double-probe pH monitoring were analyzed, first by visual inspection of the 24-hour tracing and second by leaving out the intake periods. As to the registration of gastroesophageal reflux, the inclusion or omission of meals and beverages hardly influenced the data. However, the registration of laryngopharyngeal reflux was severely biased by intake of food and beverages and other artifacts. Leaving out meals and beverages did not correct for all artifacts. Therefore, we recommend review of each laryngopharyngeal pH dro
Neuroendocrine neoplasms of the middle ear: Unpredictable tumor behavior and tendency for recurrence
BACKGROUND: Middle ear adenomatous neuroendocrine tumors (MEANTs) are rare temporal bone tumors. This study evaluates its clinical behavior and therapy outcome. METHOD: Retrospective case review in a tertiary referral center evaluating histopathology, immunohistochemistry, treatment, and outcome. RESULTS: Nine patients were diagnosed with MEANT. One patient presented with locally invasive tumor and underwent extensive en-bloc tumor resection with adjuvant radiotherapy. Seven of eight patients with locally non-aggressive tumor confined to the tympanomastoid space underwent tumor resection. Two patients were disease-free, five presented recurrence, even after apparent successful surgery. All tumors showed neuroendocrine features. Histopathology and immunohistochemistry did not yield prognostic tumor characteristics. CONCLUSION: MEANTs are rare tumors with uncertain biological behavior and subsequent unpredictable clinical course. The preferred treatment is complete surgical tumor resection. They have a high tendency for recurrence, irrespective of negative intermediary surgery. As of yet, there are no prognostic biomarkers, including histopathology and immunohistochemistry
Evaluation of subclasses for T4-classified squamous cell carcinoma of the external auditory canal
BACKGROUND: T4-classified squamous cell carcinoma (SCC) of external auditory canal (EAC) can potentially involve different anatomical structures, which could translate into different treatment strategies and survival outcomes within one classification. Our aim is to evaluate the clinical added value of T4-subclasses proposed by Lavieille and by Zanoletti. METHODS: Retrospective data, including patients with primary operated cT4-classified EAC SCC, was obtained from 12 international hospitals. We subclassified according to the T4-subclasses. The treatment strategies, disease-free survival (DFS) and overall survival per subclass were calculated. RESULTS: A total of 130 T4-classified EAC SCC were included. We found commonly used treatment strategies per subclass according to Lavieille and the DFS seems also to differ per subclass. Subclass according to Zanoletti showed comparable treatment strategies and survival outcomes per subclass. CONCLUSION: Our study suggests that the subclass according Lavieille might have added value in clinical practice to improve care of T4-classified EAC SCC
Evaluation of the modified Pittsburgh classification for predicting the disease-free survival outcome of squamous cell carcinoma of the external auditory canal
Background: Squamous cell carcinoma (SCC) of the external auditory canal (EAC) is a rare disease, which is commonly classified with the modified Pittsburgh classification. Our aim was to evaluate the predictive performance of this classification in relation to disease-free survival (DFS). Methods: We examined retrospective data from a nationwide Dutch cohort study including patients with primary EAC SCC. These data were combined with individual patient data from the literature. Using the combined data, the predictive performances were calculated using the c-index. Results: A total of 381 patients were included, 294 for clinical and 281 for the pathological classification analyses. The c-indices of the clinical and the pathological modified Pittsburgh classification predicting DFS were 0.725 (0.668-0.782) and 0.729 (0.672-0.786), respectively. Conclusion: The predictive performance of the modified Pittsburgh classification system as such appears to be acceptable to predict the DFS of EAC SCC. Other factors need to be added to a future model to improve the predicted performance