[Tonsillectomy in adults: Length of hospital stay has no influence on the frequency of postoperative hemorrhage]. / Tonsillektomie bei Erwachsenen: Kein Einfluss der stationären Aufenthaltsdauer auf die Nachblutungshäufigkeit.

BACKGROUND: Tonsillectomies (TE) in Germany are traditionally performed during inpatient hospital stays. Socioeconomic changes in the healthcare system have resulted in shorter hospital stays. OBJECTIVES: The aim of the study was to investigate whether a shorter hospital stay of 2 days leads to increased postoperative bleeding after TE. Factors affecting the duration of hospitalization were also studied. MATERIALS AND METHODS: The relevant data of all patients (≥ 14 years) undergoing TE in the ENT Clinic of the Charité Universitätsmedizin Berlin, Campus Benjamin Franklin, between 2011 and 2013 were recorded anonymously. Risk factors for bleeding after TE were analyzed. Additionally, patients who had a hospital stay of 2 days (since 2013) were compared with patients hospitalized for ≥ 3 days, and the influence of various risk factors on the length of hospital stay was analyzed. RESULTS: During the study period 2011-2013, 376 procedures were performed and data from 213 patients was collected for analysis. Median patient age was 26 years (range 14-73 years). The rate of primary hemorrhage (up to 24 hours after TE) was 2% and the rate of secondary bleeding (later than 24 hours) was 24%. In 7% of patients with postoperative haemorrhage (primary and secondary) surgical hemostasis was performed. Male gender was associated with a significantly higher haemorrhage rate. Shortening postdischarge surveillance to only 2 days did not affect the postoperative bleeding rate. CONCLUSION: The duration of stationary monitoring following TE should not only be based on the rate of secondary bleeding, but also on patient comfort and safety. A shortening of postoperative monitoring to only 2 days had no effect on the haemorrhage frequency after TE and can therefore, be considered for adults who do not live alone and are within a reasonable distance to a hospital.

[Cancer stem cell phenotypes and miRNA: therapeutic targets in head and neck squamous cell carcinoma]. / Tumorstammzellphänotypen und miRNA : Therapietargets bei Kopf-Hals-Plattenepithelkarzinomen.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. HNSCC is caused by persistent high-risk human papillomavirus (HR-HPV) infection or excessive consumption of alcohol or tobacco. The persistently low survival rates result from local recurrences and metastases, which are probably caused by so-called tumor stem cells (TSCs). The epithelial-mesenchymal transition (EMT) or transformation is a key event in metastasis initiation and is being increasingly associated with TSCs. OBJECTIVES: This review describes new therapeutic targets in HNSCC, focusing on the TSC hypothesis and EMT regulation. MATERIALS AND METHODS, RESULTS: TSCs and EMT are regulated directly and indirectly via transcription factors and microRNAs (miRNAs). These miRNAs regulate multiple cellular processes and may serve as new therapeutic targets, whose modulation could increase the effectiveness of HNSCC treatments. Post-transcriptionally, miRNAs regulate transcription factors associated with EMT (ZEB1/2, EZH2, Bmi-1), tumor suppressors (p53), TSC markers (ALDH, CD44, EpCAM, p63) and both epithelial (E-cadherin) and mesenchymal markers (vimentin). CONCLUSION: Alterations in HNSSC TSC miRNA expression before and after chemotherapy could potentially serve as a therapeutic control. In the long term, knowledge of a patient's individual protein expression pattern may permit application of specific chemotherapy. Such individualized therapy might prohibit the development of metastases and potentially unresectable recurrences with a high resistance to radiation and chemotherapy, thus improving the prognosis in HNSCC patients.

[Role of miRNA in malignoma of the head and neck]. / Die Rolle von miRNA bei Kopf-Hals-Malignomen.

Despite optimized therapeutic strategies, the long-term survival of head and neck squamous cell carcinomas (HNSCC) has improved in recent years only slightly. Most studies on the tumor cell genome focus on protein-coding genes (exons). Data on changes within the non-coding sequences (introns) are limited. miRNAs (microRNA, miR) are small non-coding single-stranded RNAs that control gene expression at the posttranscriptional level by interacting with the mRNA. miRNA functions include many biological processes and control up to 50 % of human genes. They can have oncogenic or tumor suppressive functions. Altered expression patterns of miRNAs are involved in carcinogenesis and tumor progression even in HNSCC, or those processes (increased resistance to radiation or chemotherapy) that could be responsible for the poor long-term prognosis by forming metastases and inoperable local recurrences. Therefore, we here present miRNA groups, which are involved in these processes and may serve as new potential therapeutic treatment targets. miRNAs may also serve as biomarkers for early diagnosis, evaluation and monitoring of treatment and tumor recurrence. Alterations in miRNA expression before and after chemotherapy are therefore of high interest. In the long run, this knowledge could lead to more effective therapies with improved therapeutic outcome of HNSCC.

[Central auditory prosthesis]. / Zentral-auditorische Implantate.

Deaf patients with severe sensory hearing loss can benefit from a cochlear implant (CI), which stimulates the auditory nerve fibers. However, patients who do not have an intact auditory nerve cannot benefit from a CI. The majority of these patients are neurofibromatosis type 2 (NF2) patients who developed neural deafness due to growth or surgical removal of a bilateral acoustic neuroma. The only current solution is the auditory brainstem implant (ABI), which stimulates the surface of the cochlear nucleus in the brainstem. Although the ABI provides improvement in environmental awareness and lip-reading capabilities, only a few NF2 patients have achieved some limited open set speech perception. In the search for alternative procedures our research group in collaboration with Cochlear Ltd. (Australia) developed a human prototype auditory midbrain implant (AMI), which is designed to electrically stimulate the inferior colliculus (IC). The IC has the potential as a new target for an auditory prosthesis as it provides access to neural projections necessary for speech perception as well as a systematic map of spectral information. In this paper the present status of research and development in the field of central auditory prostheses is presented with respect to technology, surgical technique and hearing results as well as the background concepts of ABI and AMI.

The influence of the coupling of actuation drivers of implantable hearing systems on the mechanics of the middle ear.

We used multifrequency tympanometry to provide middle ear mechanics after implantation of different implantable hearing aids. A total of 34 patients were included in the investigation; 19 of them were fitted with the Otologics system and 15 with the MED-EL Vibrant Soundbridge system. With the Otologics recipients, measurements were made preoperatively and both two months and at least 12 months postoperatively. Measurements involving the MED-EL patients were taken at least 12 months postoperatively. For all measurements, the non-implanted contralateral side was used as a control. Preoperatively, the resonance frequency of the Otologics patients was 904.3 +/- 218.2 Hz for the implanted side and 907.1 +/- 161.8 Hz for the non-implanted side. Postoperatively, a significant increase (p < 0.01) compared with the preoperative value and the control side was observed after two months: 1111.3 +/- 234.7 Hz, as opposed to 823.8 +/- 274.5 Hz on the contralateral side. After 12 months, the resonance point was restored to approximately the preoperatively measured values: 975 +/- 55.3 Hz (implanted side) and 901.3 +/- 207.1 (control side). The resonance frequency in the Symphonix patients, as measured after at least 12 months (on average, 35 months), was 1006.3 +/- 269.5 Hz on the non-implanted side and 900.1 +/- 249.3 Hz on the implanted side. It is apparent that the resonance frequency on the implanted side was higher than on the control side, although the difference was not significant (p = 0.496). Monitoring following the implantation of active hearing systems is therefore recommended in order that conclusions can be drawn regarding the adequacy of the coupling of the actuation driver to the ossicular chain.

Effects of phase duration and pulse rate on loudness and pitch percepts in the first auditory midbrain implant patients: Comparison to cochlear implant and auditory brainstem implant results.

The auditory midbrain implant (AMI), which is designed for stimulation of the inferior colliculus (IC), is now in clinical trials. The AMI consists of a single shank array (20 contacts) and uses a stimulation strategy originally designed for cochlear implants since it is already approved for human use and we do not yet know how to optimally activate the auditory midbrain. The goal of this study was to investigate the effects of different pulse rates and phase durations on loudness and pitch percepts because these parameters are required to implement the AMI stimulation strategy. Although each patient was implanted into a different region (i.e. lateral lemniscus, central nucleus of IC, dorsal cortex of IC), they generally exhibited similar threshold versus phase duration, threshold versus pulse rate, and pitch versus pulse rate curves. In particular, stimulation with 100 mus/phase, 250 pulse per second (pps) pulse trains achieved an optimal balance among safety, energy, and current threshold requirements while avoiding rate pitch effects. However, we observed large differences across patients in loudness adaptation to continuous pulse stimulation over long time scales. One patient (implanted in dorsal cortex of IC) even experienced complete loudness decay and elevation of thresholds with daily stimulation. Comparing these results with those of cochlear implant and auditory brainstem implant patients, it appears that stimulation of higher order neurons exhibits less and even no loudness summation for higher rate stimuli and greater current leakage for longer phase durations than that of cochlear neurons. The fact that all midbrain regions we stimulated, which includes three distinctly different nuclei, exhibited similar loudness summation effects (i.e. none for pulse rates above 250 pps) suggests a possible shift in some coding properties that is affected more by which stage along the auditory pathway rather than the types of neurons are being stimulated. However, loudness adaptation occurs at multiple stages from the cochlea up to the midbrain.

[Image-guided minimal-invasive cochlear implantation--experiments on cadavers]. / Navigationsgeführte minimal-invasive Cochlea-Implantation--Untersuchungen am humanen Felsenbein.

BACKGROUND: The accuracy of navigation systems can be improved significantly by using high-resolution flat panel-based Volume Computed Tomography (fpVCT) so that new surgical therapeutic concepts become feasible. A navigation-guided minimally-invasive cochleostomy places highest requirements on the accuracy of intraoperative navigation. METHODS: A flat-panel Volume Computed Tomograph (fpVCT) was used to scan four human temporal bones. The isometric voxel size was 200 microm. The preoperative planning was used to define an optimized drilling channel from the mastoid surface to the round window niche and the scala tympani providing a safety margin to critical anatomical structures such as facial nerve, chorda tympani, sigmoid sinus and posterior wall of auditory canal. The canal was drilled hand-operated with a navigated drill following the previously planned trajectory. Afterwards the drilled canal was imaged by fpVCT. Conventional dissection including mastoidectomy and posterior tympanotomy assured correct localization of the cochleostomy. RESULTS: Path planning took an average of 54 minutes (range 35-85 minutes). Installation took an average of 16 minutes (range 14-19 minutes). The drilling procedure itself took an average of 7.75 min (range 5-12 minutes.) The RMSE-values varied between 0.1 and 0.2 mm (Table 1). All four specimens showed a cochleostomy located at the scala tympani anterior inferior to the round window. The chorda tympani was damaged in one specimen--this was preoperatively planned as a narrow facial recess was encountered. The time needed for planning and system-installation could be reduced continuously. CONCLUSIONS: This feasibility study demonstrates that using current image-guided surgery technology in combination with fpVCT allows drilling of a minimally invasive channel to the cochlea with loco typico cochleostomy. The necessary accuracy of intraoperative navigation can be achieved by use of fpVCT (technical accuracy between 0.1 and 0.2 mm). Our results demonstrate the feasibility of a navigation-guided minimally-invasive cochleostomy loco typico. While we are enthused by this preliminary work, we recognize the barriers which exist in translation to clinical application. These include surgical issues (e.g. control of unexpected bleeding) and electrode issues (e.g. development of insertion tools).