T. Klenzner

The benefits of sequential bilateral cochlear implantation for hearing-impaired children

Conclusion. Sequential bilateral implantation offers listening advantages demonstrable on speech recognition in noise and for lateralization. Whilst the trend was for shorter inter-implant intervals and longer implant experience to positively impact binaural advantage, we observed no contraindications for binaural advantage. Objective. To evaluate the benefits of sequential bilateral cochlear implantation over unilateral implantation in a multicentre study evaluating speech recognition in noise and lateralization of sound. Subjects and methods. Twenty children, implanted bilaterally in sequential procedures, had the following characteristics: they were native German-speaking, were3 years or older and had a minimum of 1 year inter-implant interval and had between 2 months and 4 years 7 months binaural listening experience. Binaural advantage was assessed including speech recognition in noise using the Regensburg modification of the Oldenburger Kinder-Reimtest (OLKI) and lateralization of broadband stimuli from three speakers. Results. A significant binaural advantage of 37% was observed for speech recognition in noise. Binaural lateralization ability was statistically superior for the first and second implanted ear (p=0.009, p=0.001, respectively). Binaural experience was shown to correlate moderately with absolute binaural speech recognition scores, with binaural advantage for speech recognition and with binaural lateralization ability. The time interval between implants correlated in an inverse direction with binaural advantage for speech recognition.

Navigation as a quality management tool in cochlear implant surgery.

This cadaver study assessed the value of navigation in cochlear implant surgery. Cochlear implantation was simulated on a cadaver using a Stryker-Leibinger navigation system and a Nucleus 24 Contour implant. A conventional surgical strategy consisting of mastoidectomy, posterior tympanotomy, and cochleostomy was performed. The navigated surgical procedure was evaluated for accuracy, reliability, reproducibility, and practicability. The technology of computer-assisted surgery is applicable in cochlear implantation and beneficial in as much as the navigation-controlled implantation constitutes a non-invasive instrument of quality management. Nevertheless, in order to keep the point accuracy below one millimeter, a referencing method using concealed bordering anatomical structures may be further needed to perform the cochleostomy reliably under the guidance of a navigation system. More reproducible reference systems are needed if navigated lateral skull base surgery is to be fully relied upon.

Imaging procedures in cochlear implant patients – evaluation of different radiological techniques

The purpose of this study was to evaluate the feasibility and usability of different radiologic methods (single-slice computed tomography (CT), multi-slice CT and rotational tomography (RT)) for assessment of the position of cochlear implant electrodes. Cochlear implants in an isolated human temporal bone and in a complete formalin-fixed cadaver head were examined and the electrode position was determined. Subsequently, the labyrinth bone was isolated out of the cadaver head and histologically examined to compare the results of histology with imaging. Single-slice CT reliably identifies the electrode inside the human cochlea; however, due to the technically based large electrode artifact its position inside the cochlear spaces (e.g. electrode position in scala tympani or scala vestibuli) cannot be detected. Multi-slice CT of the cadaver head also showed artifacts that complicate the assessment of electrode position. Using RT the electrode artifact is small and therefore the electrode position within the cochlear spaces, scala tympani versus scala vestibuli, can be assessed. This technique was also applicable in a complete cadaver head, which is in contrast with former studies. In conclusion, CT allows the identification of electrode arrays inside the human cochlea. Multi-slice CT permits a much more precise depiction of the electrode inside the cochlea. RT alone has minimized electrode artifacts to a high extent and permits the assessment of the electrode position within the scala tympani or scala vestibuli. As RT was performed successfully in a complete cadaver head, further studies for evaluation of the intracochlear electrode position can now be performed in patients.

Evaluation of the HiFocus® electrode array with positioner in human temporal bones

The aim of the study presented was to assess the insertion mode and possible intracochlear trauma after implantation of the HiFocus electrode with positioner in human temporal bones. The study was performed in five freshly frozen temporal bones. The position of electrodes was evaluated using conventional X-ray analysis, rotational tomography and histomorphological analysis. Insertion of the HiFocus electrode with positioner resulted in considerable trauma to fine cochlear structures including fracture of the osseous spiral lamina, dislocation of the electrode array from the scala tympani into the scala vestibuli and fracture of the modiolus close to the cochleostomy. The implication of the results regarding clinical outcome will be discussed.

Objektivierung von Therapieergebnissen in der Schädelbasischirurgie durch virtuelle Modellanalyse

BACKGROUND Virtual model analysis of patient head tracking allows for objectivity and the monitoring of therapeutic results of pathologies in the skull base region. The introduction of these models in clinical routine has been impaired by the extended time needed for the preparation of radiological data. METHODS Quality control analysis was carried out for seven cases with different pathological findings in the skull base region in patients who had undergone virtual model analysis. RESULTS Preparation time of radiological data for the process of segmentation required, under optimal conditions, a minimum of 30 min. Virtual model analysis enables spatial visualization of regions of interest and adjacent anatomical structures. This improves case-specific pathoanatomical understanding as well as preoperative planning of surgical strategies. CONCLUSIONS Virtual model analysis improves the physicians spatial comprehension of localized pathological findings at the dysmorphic interface of bone and soft tissue across the skull base. Therefore, it seems to be an adequate tool for quality control analysis of therapeutic results after extended skull base surgery.

Use of a mechatronic robotic camera holding system in head and neck surgery

BACKGROUND It has been shown that a third hand is useful for holding the endoscope during endoscopic surgery so that both hands of the surgeon are free for instrumentation. MATERIAL AND METHODS Experimental tests were performed with the mechatronic robotic camera holding system Soloassist on anatomical specimens in the area of the nose, nasopharynx and larynx. RESULTS An ergonomic set-up and the practical application are easily possible. The third hand enables a still and clear picture without undesired camera movement and all instruments can be controlled by the surgeon. There would appear to be some room for improvement as the working area is limited due to an additional instrument. The camera holding system shows a very high velocity for head and neck surgery. CONCLUSION Until the active holder can be used regularly in clinical practice in the field of head and neck surgery, more technical modifications have to be implemented.

Anwendung eines aktiven Haltearms in der endoskopischen Kopf-Hals-Chirurgie

BACKGROUND It has been shown that a third hand is useful for holding the endoscope during endoscopic surgery so that both hands of the surgeon are free for instrumentation. MATERIAL AND METHODS Experimental tests were performed with the mechatronic robotic camera holding system Soloassist on anatomical specimens in the area of the nose, nasopharynx and larynx. RESULTS An ergonomic set-up and the practical application are easily possible. The third hand enables a still and clear picture without undesired camera movement and all instruments can be controlled by the surgeon. There would appear to be some room for improvement as the working area is limited due to an additional instrument. The camera holding system shows a very high velocity for head and neck surgery. CONCLUSION Until the active holder can be used regularly in clinical practice in the field of head and neck surgery, more technical modifications have to be implemented.

Rotational tomography in cochlear implant patients: a new tool for quality control of the electrode position.

Major insertion failures may complicate cochlear implant surgery and result in revision surgery. Our study demonstrated the feasibility of plain X-ray in transorbital projection to identify major insertion failures. In contrast to the cochlear-view X-ray (Xu et al., 2000), recommended for the estimation of electrode to modiolus proximity, a transorbital projection is easy to perform, even intraoperatively, and does not need a specialized setting angle. The electrode position could be identified with regard to the labyrinth, and this was confirmed by CT. It is preferable to evaluate the electrode position intraoperatively in all cases of doubt, as revision surgery with delay may be complicated and would need an additional surgical procedure. So we recommend to have at least plain Xray available in the operating room for the assessment of the electrode position. In addition, a CT scan reliably helps to identify a malpositioned electrode (Jain and Mukherji, 2003) but may not be available intraoperatively in all clinics performing cochlear implants. Each radiological technique for the evaluation of the electrode position needs exact assessment, and training in correct diagnosis is required.

[Insertion results for Contour™ and Contour Advance™ electrodes: are there individual learning curves?].

The aim of our study was to evaluate results of insertion following cochlear implantation with Contour™ and Contour Advance™ electrode arrays in adult patients and to analyze individual insertion results for three experienced surgeons. We performed a retrospective analysis of postoperative 3D volume tomography results in 223 adult patients. The intracochlear electrode position was evaluated to be in scala tympani, scala vestibuli or with a dislocation from one scala to the other. Surgical methods were analyzed and assigned to the different surgeons. We observed a significant increase for scala tympani insertions from initially 33% to 84% and a reduction in dislocations from scala tympani to scala vestibuli from 71% with the Contour™ electrode to 22% with the Contour Advance™ electrode. Results for the different surgeons varied individually with regard to scala tympani insertion rates and dislocation rates over time. 3D Volume tomography offers an important method for postoperative quality control following cochlear implant surgery. The intracochlear electrode position could be determined in all cases. We were able to identify individual learning curves for insertion results. Controlling the insertion quality serves as a feedback of surgical results and may be helpful for improving surgical quality and thus rehabilitation results.ZusammenfassungZiel der Untersuchung war die Evaluation der Insertionsergebnisse nach Cochleaimplantation von Contour™- und Contour-Advance™-Elektrodenträgern bei erwachsenen Patienten sowie die Verfolgung der individuellen Insertionsergebnisse dreier erfahrener Chirurgen. Anhand der routinemäßig durchgeführten postoperativen 3-D-Volumentomographie bei 223 erwachsenen Patienten mit Lagebestimmung der Elektrode in der Cochlea (Scala tympani, Scala vestibuli, Dislokation von einer in die andere Scala). wurde retrospektiv das chirurgische Vorgehen analysiert und den jeweiligen Chirurgen zugeordnet. Die Scala-tympani-Insertionen stiegen von initial 33 auf 84% signifikant an. Mit Verwendung der Contour-Advance™-Elektrode sank gleichzeitig die Dislokationsrate aus der Scala tympani in die Scala vestibuli von initial 71% mit der Contour™-Elektrode auf 22%. Für die einzelnen Chirurgen zeigten sich individuelle Unterschiede in Bezug auf die Scala-tympani-Insertionsraten und die Dislokationsraten im Untersuchungszeitraum. Mit der 3-D-Volumentomographie ließ sich die Elektrodenposition in allen Fällen evaluieren, sodass ein wertvolles Instrument zur Qualitätskontrolle vorliegt. Gleichzeitig stellten sich individuelle Lernkurven dar. Die Kontrolle der Insertionsqualität ist notwendig, um durch ein Feedback der Insertionsergebnisse die chirurgische Qualität verbessern zu helfen und konsekutiv die Rehabilitationsergebnisse zu verbessern.AbstractThe aim of our study was to evaluate results of insertion following cochlear implantation with Contour™ and Contour Advance™ electrode arrays in adult patients and to analyze individual insertion results for three experienced surgeons. We performed a retrospective analysis of postoperative 3D volume tomography results in 223 adult patients. The intracochlear electrode position was evaluated to be in scala tympani, scala vestibuli or with a dislocation from one scala to the other. Surgical methods were analyzed and assigned to the different surgeons. We observed a significant increase for scala tympani insertions from initially 33% to 84% and a reduction in dislocations from scala tympani to scala vestibuli from 71% with the Contour™ electrode to 22% with the Contour Advance™ electrode. Results for the different surgeons varied individually with regard to scala tympani insertion rates and dislocation rates over time. 3D Volume tomography offers an important method for postoperative quality control following cochlear implant surgery. The intracochlear electrode position could be determined in all cases. We were able to identify individual learning curves for insertion results. Controlling the insertion quality serves as a feedback of surgical results and may be helpful for improving surgical quality and thus rehabilitation results.

Insertionsergebnisse von Contour™- und Contour-Advance™-Elektroden

The aim of our study was to evaluate results of insertion following cochlear implantation with Contour™ and Contour Advance™ electrode arrays in adult patients and to analyze individual insertion results for three experienced surgeons. We performed a retrospective analysis of postoperative 3D volume tomography results in 223 adult patients. The intracochlear electrode position was evaluated to be in scala tympani, scala vestibuli or with a dislocation from one scala to the other. Surgical methods were analyzed and assigned to the different surgeons. We observed a significant increase for scala tympani insertions from initially 33% to 84% and a reduction in dislocations from scala tympani to scala vestibuli from 71% with the Contour™ electrode to 22% with the Contour Advance™ electrode. Results for the different surgeons varied individually with regard to scala tympani insertion rates and dislocation rates over time. 3D Volume tomography offers an important method for postoperative quality control following cochlear implant surgery. The intracochlear electrode position could be determined in all cases. We were able to identify individual learning curves for insertion results. Controlling the insertion quality serves as a feedback of surgical results and may be helpful for improving surgical quality and thus rehabilitation results.ZusammenfassungZiel der Untersuchung war die Evaluation der Insertionsergebnisse nach Cochleaimplantation von Contour™- und Contour-Advance™-Elektrodenträgern bei erwachsenen Patienten sowie die Verfolgung der individuellen Insertionsergebnisse dreier erfahrener Chirurgen. Anhand der routinemäßig durchgeführten postoperativen 3-D-Volumentomographie bei 223 erwachsenen Patienten mit Lagebestimmung der Elektrode in der Cochlea (Scala tympani, Scala vestibuli, Dislokation von einer in die andere Scala). wurde retrospektiv das chirurgische Vorgehen analysiert und den jeweiligen Chirurgen zugeordnet. Die Scala-tympani-Insertionen stiegen von initial 33 auf 84% signifikant an. Mit Verwendung der Contour-Advance™-Elektrode sank gleichzeitig die Dislokationsrate aus der Scala tympani in die Scala vestibuli von initial 71% mit der Contour™-Elektrode auf 22%. Für die einzelnen Chirurgen zeigten sich individuelle Unterschiede in Bezug auf die Scala-tympani-Insertionsraten und die Dislokationsraten im Untersuchungszeitraum. Mit der 3-D-Volumentomographie ließ sich die Elektrodenposition in allen Fällen evaluieren, sodass ein wertvolles Instrument zur Qualitätskontrolle vorliegt. Gleichzeitig stellten sich individuelle Lernkurven dar. Die Kontrolle der Insertionsqualität ist notwendig, um durch ein Feedback der Insertionsergebnisse die chirurgische Qualität verbessern zu helfen und konsekutiv die Rehabilitationsergebnisse zu verbessern.AbstractThe aim of our study was to evaluate results of insertion following cochlear implantation with Contour™ and Contour Advance™ electrode arrays in adult patients and to analyze individual insertion results for three experienced surgeons. We performed a retrospective analysis of postoperative 3D volume tomography results in 223 adult patients. The intracochlear electrode position was evaluated to be in scala tympani, scala vestibuli or with a dislocation from one scala to the other. Surgical methods were analyzed and assigned to the different surgeons. We observed a significant increase for scala tympani insertions from initially 33% to 84% and a reduction in dislocations from scala tympani to scala vestibuli from 71% with the Contour™ electrode to 22% with the Contour Advance™ electrode. Results for the different surgeons varied individually with regard to scala tympani insertion rates and dislocation rates over time. 3D Volume tomography offers an important method for postoperative quality control following cochlear implant surgery. The intracochlear electrode position could be determined in all cases. We were able to identify individual learning curves for insertion results. Controlling the insertion quality serves as a feedback of surgical results and may be helpful for improving surgical quality and thus rehabilitation results.