Matthias Helbig

Hearing preservation after complete cochlear coverage in cochlear implantation with the free-fitting FLEXSOFT electrode carrier.

Objectives: To demonstrate the possibility of atraumatic insertion with the free-fitting FLEXSOFT electrode by evaluating the degree of hearing preservation postoperatively. Design: Retrospective study. Setting: Academic tertiary care center. Participants: Twenty-two severely to profoundly hearing impaired subjects with measurable residual hearing preoperatively. Intervention: Atraumatic implantation with the 31.5-mm-long, free-fitting, and highly flexible FLEXSOFT electrode using either the round window approach or a cochleostomy technique. Main Outcome Measures: Subjects were tested preoperatively in unaided condition and at varying intervals postoperatively. Preoperative and postoperative low-frequency pure-tone average (PTA) and PTA shifts were calculated. Speech perception was measured preoperatively and postoperatively using the Freiburger monosyllabic word test in quiet. Results: Preoperative low-frequency hearing could be preserved to a certain degree in 77.3% of subjects (17/22) after insertion of the FLEXSOFT electrode up to the point of first resistance. Complete loss of residual hearing was observed in 22.7% of subjects (5/22). In 18.2% of the subjects (4/22), the preoperative PTA was preserved within 10 dB. Pure-tone average results between preoperative and most recent testing showed statistically significant differences (p < 0.001 to p = 0.031) for almost all loudness levels ranging from 125 Hz to 1.5 kHz. The maximum threshold shift was 40 dB at 250 Hz for the lower frequencies up to 1 kHz. Monosyllable testing in quiet demonstrated significant improvement over time (p < 0.001). Conclusion: This study showed that preservation of residual hearing is possible in a high number of subjects when a flexible electrode and atraumatic surgical techniques are used.

A New Combined Speech Processor for Electric and Acoustic Stimulation -Eight Months Experience

Purpose: Electric acoustic stimulation (EAS) relies on the preservation of low-frequency hearing and adequate amplification of these frequencies. EAS has been achieved by fitting the cochlear implant (CI) speech processor together with an ipsilateral in-the-ear hearing aid. This study will evaluate the outcomes when CI/EAS users upgrade to a new combination of hearing aid and speech processor in 1 device (DUET™). Method: Nine EAS patients participated in this study. Before switchover and after 2 and 8 months of DUET device use, they were assessed using monosyllables and sentences in quiet and in noise. Additionally, a questionnaire, the Abbreviated Profile for Hearing Aid Benefit (APHAB), was used to evaluate subjective impressions. Results: All subjects performed equally well, or even better, after switchover. This was also demonstrated over time. The participants with EAS before switchover performed equally afterwards, while those who used CI only did markedly better with the new device, especially in noisy conditions. Slight preference for the new system was also demonstrated with the APHAB. Conclusion: All subjects showed benefit in noise; CI-only users before switchover particularly benefited from the new hearing system. Those who applied EAS before switchover performed equally well. The DUET allows individuals better access to EAS.

Evaluation of an electrode prototype for atraumatic cochlear implantation in hearing preservation candidates: preliminary results from a temporal bone study.

Objectives: This study aimed to evaluate an atraumatic prototype electrode carrier for cochlear implantation, the FLEXEAS 20 electrode. This electrode is designed to preserve hearing and to achieve a 360-degree insertion. Study Design: A cross-sectional human temporal bone study was conducted. Setting: Preliminarily, the prototype electrode was inserted in a scala tympani model to measure the insertion force. Thirteen human temporal bones were acquired postmortem and implanted with the new device using the round window approach. Three of them were implanted under radiologic control to demonstrate the insertion path. After embedding, the remaining 10 temporal bones were sectioned undecalcified and examined macroscopically and histologically. Main Outcome Measures: The insertion force was measured to determine intracochlear resistance peaks. The insertion angle was measured, and the degree of intracochlear trauma was determined. Results: The round window approach caused cochlear trauma in 1 of 10 specimens. An exact 360-degree insertion was achieved in 7 of 10 specimens (mean overall insertion angle, 360 degrees). Radiologic examination and insertion force measurements revealed the smooth and atraumatic insertion. Conclusion: The new prototype electrode carrier is suitable for clinical application. It can be handled easily and allows atraumatic 360-degree insertion of all electrode contacts. Therefore, this electrode concept allows good coverage of the cochlea for electrical and additional acoustic stimulation.

Scalar localization by computed tomography of cochlear implant electrode carriers designed for deep insertion.

Objectives This study aimed to evaluate the possibility of predicting radiologically the scalar localization of a 31.5-mm-long, free-fitting electrode carrier for cochlear implantation, using conventional planar computed tomography. Study Design A cross-sectional human temporal bone study was conducted. Setting Twenty human temporal bones were acquired postmortem and implanted with 31.5-mm-long electrode carriers. Ten of these were implanted into the scala tympani using the round window approach, whereas the other 10 electrodes were inserted into the scala vestibuli by cochleostomy. Computed tomography was then performed, and 2 experienced blinded radiologists evaluated the intracochlear position of the array. Main Outcome Measure The estimated position of the electrode carrier was described using a 5-point scale. After sectioning and histologic investigation, the results of the radiologic and histologic investigations were compared. Results In 17 of 20 cases, it was possible to estimate the correct position of the electrode carrier within the basal turn of the cochlea by means of computed tomography. As the insertion angles widened beyond 360 degrees, it became increasing difficult for the radiologists to correctly determine the position of the electrode carrier. Conclusion The comparison of our temporal bone experiment results with the computed tomography results revealed the difficulty of assessing the correct position of intracochlear electrodes. Scalar localization of deeply inserted electrode carriers cannot be precisely determined by means of computed tomography.

Hearing preservation and improved speech perception with a flexible 28-mm electrode.

Objective The present study aimed to determine the extent of hearing preservation retrospectively after atraumatic cochlear implant (CI) surgery using a specialized surgical technique and specially designed flexible electrode to minimize cochlear trauma. Study Design Retrospective study. Setting Academic tertiary care center. Patients A consecutive series of 34 patients who had some preoperative residual hearing were included in this study. Intervention Patients underwent CI surgery with a flexible 28-mm electrode using a round window insertion technique. Main Outcome Measures All patients had at least 6 months of postoperative follow-up including audiometric testing and speech perception determined using the Freiburg monosyllable word test and the Oldenburger Sentence Test in noise. Audiometric testing served as a proxy for the evaluation of cochlear trauma and hearing preservation. Results Hearing was preserved to within 20 dB of preoperative low-frequency pure-tone audiometry (PTA) in 40.7% of patients. Hearing was preserved to within 20 dB of preoperative high-frequency PTA in 35.7% of patients. Overall, a deterioration in hearing thresholds was observed between preoperative assessment and first fitting. Speech perception improved significantly over time after surgery. Conclusion Using appropriate surgical techniques, and electrodes specially designed to minimize cochlear trauma, hearing preservation can be achieved.

Development of prototype for navigated real-time sonography for the head and neck region

To date, few imaging methods have been established for the head and neck region, in particular for soft tissues, that allow adequate visualization and simultaneously adequate real‐time orientation.

NAVIGATION-SUPPORTED AND SONOGRAPHICALLY-CONTROLLED FINE-NEEDLE PUNCTURE IN SOFT TISSUES OF THE NECK

In surgery, sonography has been a well-accepted means of orientation for years. The immediate vicinity of many vital structures in the head and neck region calls for a very exact visualization of the surgical instrument in the 2-D ultrasonic picture. We report on the development of a new method for navigation-supported and sonographically-controlled fine-needle puncture in soft tissues of the neck. Our system comprises a navigated ultrasound probe, a navigated fine-puncture needle and a coordinate sensor. A personal computer with specially-developed software assists calibration and surgical application. The applicability test for the system is described. In vitro, a model lymph node of 9 mm in diameter had been hit. It is shown that the target structure can be aimed at very precisely by the navigated puncture needle. An accuracy of 97% and a specificity of 99% could be demonstrated. The development of a very precise and easy-to-handle method for navigation-supported fine-needle puncture in the neck region is presented. The outstanding advantage of this method is that no rigid reference gadget fixed to the patients body is necessary. That makes this method very suitable for surgery in the neck region. Contrary to other sonographically-supported navigation methods in the head and neck region, preoperative imaging (CT or MRT) is dispensable.

Cochlear Reimplantation after Surgery for Electric-Acoustic Stimulation

Background/Aims: Combined electric-acoustic stimulation (EAS) of the auditory system usually results in better speech understanding than electric stimulation only, assuming low-frequency hearing can be preserved. Treatment options and outcomes for 4 subjects experiencing compromised hearing after EAS surgery are discussed. Methods: Each subject underwent revision surgery to replace the original 21-mm electrode arrays used in EAS surgery with cochlear implants (CIs) with 31-mm arrays. Our aims were: (1) to investigate whether deeper insertion is possible, and (2) to evaluate the influence of electrode insertion angle by comparing speech perception scores before and after revision surgery. Results: Deeper insertion was feasible in all subjects. Speech understanding scores after reimplantation were comparable to those seen after the first intervention. Conclusion: A 360-degree insertion under EAS conditions provides sufficient speech understanding, even in cases of additional hearing loss. Reimplantation with a longer electrode array is feasible in former EAS patients.

Certifying a university ENT clinic using the ISO 9001:2000 international standard

PURPOSE Against statutory duties to introduce quality management systems, the increased importance of this subject has led to numerous activities in various public health institutions. Following the International Standardization Organization (ISO 9001:2000) prerequisites, Frankfurt Goethe University Hospital ENT clinic staff introduced a quality management system. This paper aims to investigate this process. DESIGN/METHODOLOGY/APPROACH Designing, planning and implementing the quality management system is described. Under the supervision of an executive quality management board, clinic quality goals were defined. Thereafter, several quality management teams performed an actual state analysis as well as developing and realising improvement proposals. Finally a quality management manual containing binding standards and working instructions concerning all patient care, research and teaching aspects was written. FINDINGS Successful certification by a neutral body ascertained that the clinics quality management system conformed to current national and international standards while restructuring and reform improved procedural efficiency. ORIGINALITY/VALUE The paper shows that mplementing the quality management system requires considerable effort but patients as well as staff profit considerably from the innovation. On the whole, the positive impact on structure and workflow in a specialist clinic predominates. Therefore, implementing a quality management system in all the clinics wards and departments is recommended.

Navigationsunterstützte Weichteilsonographie für den Kopf-Hals-Bereich

BACKGROUND In soft tissue surgery of the head and neck region tissue shifts limit the usefulness of conventional CT/MRI-based navigation procedures. Furthermore, changes caused by invasive measures cannot be visualized. METHODS A novel navigation device for sonography of soft tissues was developed. This consists of a navigated ultrasound scanner, a navigated surgical instrument, and a personal computer with custom-made software. Its use makes an additional visualization by means of CT or MRI dispensable. RESULTS The system deviation (three-dimensional error) of this newly developed prototype was less than 1 mm. The practical application in a model setup showed good handling properties of the system. Orientation and approach of the surgical instrument to the sonographically visualized target structure were rapid and accurate. CONCLUSION This new navigation system does not require additional CT or MRI images. The navigated ultrasound probe shows tissue changes in real time. This navigation system is especially suitable for invasive procedures in soft tissues.