Magnetic Resonance Imaging Compatibility of a New Generation of Active Middle Ear Implant: A Clinically Relevant Temporal Bone Laboratory Study.

OBJECTIVE: Magnetic resonance imaging (MRI) has become an essential tool of modern medical imaging and disease diagnosis. In November 2014, a new MRI-conditional (up to 1.5 T) generation of an active middle ear implant (AMEI) was released to the market.The aim of the study was to test the MRI compatibility of the new implant system in a clinical-anatomical study. DESIGN: Experimental cadaver head model. SETTING: Temporal bone laboratory. PARTICIPANTS: AMEIs were implanted in 28 fixed temporal bones at three different floating mass transducer (FMT)-coupling positions (N = 8 short process of the incus, N = 16 long process of the incus, N = 4 round window). MAIN OUTCOME MEASURES: The position of the FMT and the integrity of the ossicular chain was monitored through microscopy, microendoscopy, and computed tomography (CT) scans before and after the MRI (1.5 T) was conducted. Proper function of the implant was tested with reverse transfer function (RTF) measurements. RESULTS: Neither positional nor functional changes after MRI were observed. CONCLUSION: The new generation of the AMEI is a MRI-compatible system, which features an easier and quicker implant fixation method. The option of MRI in patients with AMEI should be taken into consideration during the preoperative discussion with potential candidates.

Acute dyspnea caused by a giant spindle cell lipoma of the larynx.

BACKGROUND: The spindle cell lipoma (SCL) is a special type of lipoma and this is very rare in the head and neck regions. There are only five reported cases exist, which describes the occurrence of a SCL in the hypopharynx. METHODS: Our case report presents a case of a very large SCL in the larynx. We want to describe that how we treated the patients and compared the situation with other reported cases. RESULTS: Intraoperatively, we found a tumor mass of 7 × 5 cm. It was successfully removed with the carbon dioxide laser. No postoperative complications occurred. CONCLUSIONS: Although SCL is a very rare diagnosis in the larynx/hypopharynx, it should be included in the differential diagnosis of larynx/hypopharynx tumors. Our case is the first report of such a large SCL in the larynx. The clinical symptoms occurred relatively late and ended up in an acute situation of stridor and dyspnea.

Bilateral use of active middle ear implants: speech discrimination results in noise.

Binaural sound reception has advantages over unilateral perception, including better localization and sound quality as well as speech and tone reception in both quiet and noisy environments. Up to now, most active middle ear implant (AMEI) users have been unilaterally implanted, but patient demand for an implant on the other side is increasing. Ten bilaterally-AMEI implanted native German-speaking adults were included in the study. The Oldenburg sentence test was used to measure speech reception thresholds in noise. The subject's signal-to-noise ratio (SNR) at a speech reception score of 50 % was calculated for different noise conditions. SRT was measured as a function of noise condition (nc) and listening condition (lc)-for example, SRT (lc, nc), with nc from S0N0, S0N-90, or S0N90 and lc from left, right or both. For each noise condition, the squelch effect and the binaural summation effect were calculated. Patients in this study demonstrated improvement with bilateral AMEIs compared to right or left AMEI only in all three tested listening conditions. Statistical significance was found in the S0N0 condition to favor usage of bilateral AMI versus either the right or left side only. The benefits of binaural hearing are well known, also in normal-hearing individuals. In the future every bilateral implantation should be a part of the clinical routine. Bilateral implantation can help to reduce problems in background noise and restore directional hearing.

Evaluation of a minimally invasive surgical fixation technique for young children with the Concerto Pin cochlear implant system.

In 2011, Med-El (Innsbruck, Austria) introduced a new cochlear implant system, designed to require a minimally invasive surgical technique and allow greater positional flexibility for its fixation on the skull. The Concerto Pin implant system is a good option for patients with thinner bone, such as children and elderly. The aim of this study was to investigate the implant's stability in children using our minimally invasive surgical technique. This was a prospective, longitudinal study with a single-subject, repeated-examination design. Six children, implanted with a Concerto Pin using our minimally invasive surgical technique between October 2011 and September 2012, were assessed 1, 3 and 6 months after surgery. In each case, the implant remained in a stable position and no adverse events or problems with healing were observed at any time during the investigation. The minimally invasive technique and the method of implant fixation that bypass drilling a deep implant bed constitute a good option for patients with thinner bone, such as children. This clinical study shows the safety and stability of the Concerto Pin implant system using a minimally invasive surgical technique.

Intraoperative measurement for a new transcutaneous bone conduction hearing implant.

OBJECTIVE: To investigate the possibility of using a modified reverse transfer function (RTF) measurement intraoperatively during surgery of a new transcutaneous bone conduction hearing implant to evaluate the status of the device. METHODS: Tests were performed on a cadaver skull (preclinically) and two conductive hearing loss patients implanted with a new transcutaneous bone conduction implant. During intraoperative activation, the RTF was measured using a microphone attached perpendicularly and directly to the skin in the middle section of the forehead. RESULTS: The RTF could be measured for all frequencies from 500 to 6, 000 Hz. CONCLUSION: The usage of an intraoperative RTF measurement may be a good method to verify the mechanical coupling of the bone conduction floating mass transducer and to test the functional integrity of the implant in an objective way.

68Ga-DOTA°-Tyr³-octreotide positron emission tomography in head and neck squamous cell carcinoma.

PURPOSE: 68Ga-labelled DOTA°-Tyr³-octreotide positron emission tomography (PET)/CT (68Ga-DOTATOC PET/CT) is a routinely used imaging modality for neuroendocrine tumours expressing somatostatin receptors (SSTRs). Recent studies have shown that SSTRs are also expressed in head and neck squamous cell carcinoma (HNSCC). This is the first prospective clinical trial investigating SSTR expression in patients with HNSCC using 68Ga-DOTATOC. METHODS: Patients with previously untreated HNSCC underwent 68Ga-DOTATOC PET/CT (120 MBq, range 81-150 MBq). Tumour tracer uptake was scored, the maximum standardized uptake value (SUVmax) was measured and the tumour to background uptake ratio was calculated. For each patient, PET/CT findings were correlated with immunohistochemical SSTR expression in tumour specimens. RESULTS: Fifteen HNSCC patients were included in the study from May 2011 to May 2012. Tumour-specific 68Ga-DOTATOC uptake was detected in all patients with an median SUVmax of 4.0 (range 2.2-6.5). Uptake was weak in seven (47%), moderate in five (33%) and strong in three (20%) patients. All tumour specimens were SSTR positive on immunohistochemistry. Of the 15 patients, 14 were positive for SSTR subtype 2, characterized by the highest affinity to octreotide. CONCLUSION: SSTR expression in HNSCC can be visualized clinically using 68Ga-DOTATOC PET/CT. SSTR expression in HNSCC could provide a potential target for SSTR-based therapy in patients not amenable to standard treatment modalities, but this cannot be predicted by SSTR immunohistochemistry.

Concerto Pin: a novel concept of cochlear implant fixation.

OBJECTIVE: The Concerto Pin is a new cochlear implant system, designed by Med-El to require minimally invasive surgery and to allow greater positional flexibility in its fixation on the skull. The aim of this study was to measure the load needed to displace the implant from a human skull. STUDY DESIGN: This was a laboratory investigation under controlled conditions at the Department of Anatomy, Histology und Embryology, Innsbruck Medical University. METHODS: Using the manufacturer's surgical guidelines, a Concerto Pin cochlear implant was fixed to a fresh skull from a human cadaver. Load was applied to the body of the implant at different positions and measured with a mechanical force gauge. RESULTS: The maximum load of 100N did not cause dislocation of the implant from its position or fracture of the pins. CONCLUSION: The Concerto Pin fixation method for cochlear implants provides a secure skull attachment with a direct mechanical connection between implant and bone. It requires less drilling and no tie-down sutures; surgery should therefore be quicker and less invasive.

Sheep as a large animal model for middle and inner ear implantable hearing devices: a feasibility study in cadavers.

OBJECTIVE: Currently, no large animal model exists for surgical-experimental exploratory analysis of implantable hearing devices. In a histomorphometric study, we sought to investigate whether sheep or pig cochleae are suitable for this purpose and whether device implantation is feasible. METHODS: Skulls of pig and sheep cadavers were examined using high-resolution 128-slice computed tomography (CT) to study anatomic relationships. A cochlear implant and an active middle ear implant could be successfully implanted into the sheep's inner and middle ear, respectively. Correct device placement was verified by CT and histology. The cochlear anatomy of the sheep was further studied by micro-CT and histology. RESULTS: Our investigations indicate that the sheep is a suitable animal model for implantation of implantable hearing devices. The implantation of the devices was successfully performed by access through a mastoidectomy. The histologic, morphologic, and micro-CT study of the sheep cochlea showed that it is highly similar to the human cochlea. The temporal bone of the pig was not suitable for these microsurgical procedures because the middle and inner ear were not accessible owing to distinct soft and fatty tissue coverage of the mastoid. CONCLUSION: The sheep is an appropriate large animal model for experimental studies with implantable hearing devices, whereas the pig is not.

Adenosine stress high-pitch 128-slice dual-source myocardial computed tomography perfusion for imaging of reversible myocardial ischemia: comparison with magnetic resonance imaging.

BACKGROUND: Coronary computed tomography angiography (CTA) enables accurate anatomic evaluation of coronary artery stenosis but lacks information about hemodynamic significance. The aim of this study was to evaluate 128-slice myocardial CT perfusion (CTP) imaging with adenosine stress using a high-pitch mode, in comparison with cardiac MRI (CMR). METHODS AND RESULTS: Thirty-nine patients with intermediate to high coronary risk profile underwent adenosine stress 128-slice dual source CTP (128×0.6 mm, 0.28 seconds). Among those, 30 patients (64 ± 10 years, 6% women) also underwent adenosine stress CMR (1.5T). The 2-step CTP protocol consisted of (1) adenosine stress-CTP using a high-pitch factor (3.4) ECG-synchronized spiral mode and (2) rest-CTP/coronary-CTA using either high-pitch (heart rate <63 bpm) or prospective ECG-triggering (heart rate >63 bpm). Results were compared with CMR and with invasive angiography in 25 patients. The performance of stress-CTP for detection of myocardial perfusion defects compared with CMR was sensitivity, 96%; specificity, 88%; positive predictive value (PPV), 93%; negative predictive value (NPV), 94% (per vessel); and sensitivity, 78%; specificity, 87%; PPV, 83%; NPV, 84% (per segment). The accuracy of stress-CTP for imaging of reversible ischemia compared with CMR was sensitivity, 95%; specificity, 96%; PPV, 95%; and NPV, 96% (per vessel). In 25 patients who underwent invasive angiography, the accuracy of CTA for detection of stenosis >70% was (per segment): sensitivity, 96%; specificity, 88%; PPV, 67%; and NPV, 98.9%. The accuracy improved from 84% to 95% after adding stress CTP to CTA. Radiation exposure of the entire stress/rest CT protocol was only 2.5 mSv. CONCLUSIONS: Adenosine-induced stress 128-slice dual-source high-pitch myocardial CTP allows for simultaneously assessment of reversible myocardial ischemia and coronary stenosis, with good diagnostic accuracy as compared with CMR and invasive angiography, at a very low radiation exposure.

Active middle ear implantation in elderly people: a retrospective study.

OBJECTIVE: To evaluate the outcomes of younger (<60 yr) and older (≥60 yr) patients implanted with the Vibrant Soundbridge (VSB). The aim was to determine if there were differences between groups. METHOD: A retrospective study was used to evaluate all patients who were implanted and fit with a VSB during 2008 and 2009 at the Department of Otorhinolaryngology-Head and Neck Surgery, Medical University Innsbruck. Differences in audiologic, medical, and surgical outcomes between younger and older patients were evaluated. RESULTS: No patients had major complications during or after the surgical procedure. All patients had a good hearing benefit as supported by improvements in hearing thresholds from the preoperative to the postoperative condition in the sound field. There were differences between groups in speech understanding postoperatively; however, the differences were not statistically significant. CONCLUSION: All patients had, independent of age, good audiologic benefit from VSB use. Based on the low risk of medical or surgical complications, the easy use of the hearing implant, audiologic improvements, and potential social benefits, we think that the VSB should be regularly offered to adults with hearing loss, whether they are young or old.