[Variable length titanium prostheses for type III tympanoplasty. Intraoperative length adjustment and fixation of the cartilage overlay]. / Längenvariable Titanprothesen bei Typ-III-Tympanoplastik. Intraoperative Längeneinstellung und Fixation der Knorpelauflage.

INTRODUCTION: For type III tympanoplasty by partial ossicular replacement prosthesis (PORP) or total ossicular replacement prosthesis (TORP), the length of the prosthesis must match the individual intraoperative anatomical and physiological characteristics. MATERIALS AND METHODS: Databanks were used to determine the necessary sizer length of the sizer disc. The measurement template for the size of the cartilage to overlay the prosthesis headplate was derived from the headplates of the Tübinger titanium prostheses (TTP) and the Dresdener titanium prostheses. Finally all functions were integrated into a synthetic plate. RESULTS: The result was a simple and reasonably priced disposable multifunctional instrument (Tübinger sizer disc TSD) which allowed an exact measurement for every prosthesis in TORP and PORP. For the TTP-Variac, the TSD enabled the simple intraoperative production of prostheses with the length desired by the surgeon. For PORP the TSD enabled an adaptation of the diameter of the prosthesis foot for TTP, TTP-Vario and TTP-Variac and provided a template for the size determination of the cartilage overlay of the titanium prosthesis head. The sizers and the resulting prostheses were used for initial tympanoplastic operations. Audiometric investigations carried out 6 weeks postoperatively gave results corresponding to those previously obtained in a study with TTP and TTP-Vario using the old instrumentation. CONCLUSIONS: The new instrumentation leads to an improvement of the intraoperative practicability and a simplification. The audiological results remain the same.

[Laser-based quality assurance for robot-assisted milling at the base of the skull]. / Laserbasierte Qualitätssicherung für die robotergestützte Fräsabtragung an der Schädelbasis.

BACKGROUND: Implanting active hearing devices in the lateral base of the skull requires high-precision, secure fixation of the electromagnetic transducer and long-life anchorage using osteosynthetic fixation plates referred to as mountain brackets. Nonlinear distortion in the acoustic signal path and consecutive implant loosening can only be avoided by exact osseous milling to create the necessary cavity bed while avoiding excessive milling. Robot technology is ideal for high-precision milling. However, safety measures are necessary in order to prevent errors from occurring during the reduction process. Ideally, a robot should be guided by a navigation system. However, robotic systems so far available do not yet have an integrated global navigation system. MATERIALS AND METHODS: We used an animal model under laboratory conditions to examine the extent to which the semiautomatic ROBIN assistant system developed could be expected to increase osseous milling accuracy before implanting active electronic hearing devices into the recipient tissue in the cranium. An existing prototype system for robot-assisted skull base surgery was equipped with laser sensors for geometric measurement of the operation site. The three-dimensional measurement data was compared with CT simulation data before, during, and after the robot-assisted operation. The experiments were conducted on test objects as well as on animal models. RESULTS: Under ideal conditions, the operation site could be measured at a spatial resolution of better than 0.02 mm in each dimension. However, reflections and impurities in the operation site from bleeding and rinsing fluids did have a considerable effect on data collection, necessitating specialised registering procedures. Using an error-tolerant procedure specifically developed, the effective registering error could be kept under 0.3 mm. After milling, the resulting shape matched the intended form at an accuracy level of 0.8 mm. CONCLUSION: The results show that robot systems can reach the accuracy required for reliable microsurgery on the cranial base. High-resolution laser-based geometric measurement of the operation site enables head registration without additional artificial landmarks. During the navigated operation, the procedure can be used to ensure that the resulting cavity matches the intended shape as determined in the preoperative planning phase. This will enable quantitative analysis of, and improvement in the quality of robot-assisted surgery in the future.

[Quality of life in patients with oropharyngeal carcinoma. Gender influences the subjective evaluation]. / Lebensqualität bei Patienten mit Oropharynxkarzinom. Das Geschlecht beeinflusst die subjektive Bewertung.

BACKGROUND: The purpose of this study was to evaluate the impact of patient characteristics and surgical interventions on quality of life (QoL) after primary surgery and postoperative irradiation in patients with oropharyngeal carcinoma. PATIENTS AND METHODS: Between January 1997 and February 2002, 169 patients with carcinoma of the oropharynx were treated with curative intent. In September 2002, a total of 88 disease-free survivors were identified and included in this study. A retrospective chart review was performed and patient responses to the SF-36 Health Survey, EORTC QLQ-C30 and EORTC QLQ-H&N35 questionnaires were evaluated. The questionnaires were completed by 34 patients (39% response rate). RESULTS: All patients were treated with primary surgery followed by postoperative irradiation. The median follow-up was 2.3 years (range 0.5-4.9 years). Using Bonferroni-Holm adjustment for alpha, gender was found to be an important factor in QoL. Females scored significantly worse than males in all three questionnaires. We could not identify other factors influencing QoL. CONCLUSION: The impact of gender on QoL must be considered as very significant.

[Waardenburg syndrome. A heterogenic disorder with variable penetrance]. / Waardenburg-Syndrom. Eine heterogene Erkrankung mit variabler Penetranz.

BACKGROUND: Waardenburg syndrome (WS) is an autosomal dominant disorder characterised by pigmentary anomalies of the skin, hairs, eyes and various defects of other neural crest derived tissues. It accounts for over 2% of congenital hearing impairment. At least four types are recognized on the basis of clinical and genetic criteria. PATIENTS AND METHODS: Based on a screening of congenitally hearing impaired children, 12 families with WS type II were detected. Of special interest was the phenotype of these families, in particular the reduced penetrance of hearing impairment within the families. RESULTS AND CONCLUSION: In all cases a high variability of the disease phenotype was detected and the penetrance of the clinical traits varied accordingly. Therefore, it is not possible to predict the clinical phenotype even in a single family. Based on these studies, we plan to identify the pathogenetic cause of the disease in order to perform a detailed genotype/phenotype analysis.

[Recovery of hearing: results of delayed medical treatment in patients with idiopathic sudden hearing loss]. / Erholung der Hörschwelle bei verzögert einsetzender Therapie des Hörsturzes.

For the treatment of idiopathic sudden sensorineural hearing loss (ISSNHL), a variety of studies about intravenous drug administration with the beginning of treatment in the early period of less then one week after the onset of hearing loss have been performed. In contrast, very little information is available about the efficacy of intravenous drug therapy for ISSNHL with the beginning of treatment later than four weeks after the onset of hearing loss. In a retrospective chart review we studied the treatment results of 57 patients with ISSNHL with beginning of treatment later than four weeks after the onset of hearing loss with no spontaneous recovery of hearing. Patients received a treatment with intravenous administration of Dextran (concentration 40 g/l with NaCl 0.9%) and Procain-HCl (a derivative of the local anaesthetic lidocaine,400-800 mg in a 500 ml rheologic infusion of Dextran 40). 25% of the patients showed a significant improvement of 10 dB or more in hearing threshold at 1000 Hz measured in bone-conducted pure tone audiometry. In a subjective evaluation 53% of the patients noticed a subjective improvement of their individual hearing thresholds.

[Pharyngeal reconstruction after salvage pharyngolaryngectomy in recurrent tumors]. / Pharynxrekonstruktion nach Rettungspharyngolaryngektomie bei Rezidivtumoren.

BACKGROUND: Total pharyngeal reconstruction after salvage pharyngolarynectomy in recurrent tumors after primary surgery or radiation therapy may be performed by ENT surgeons in the oncologic field. PATIENTS: We report on six patients that underwent salvage pharyngolaryngectomy and total pharyngeal reconstruction. METHODS: In three cases pharyngeal reconstruction was performed as a two-stage procedure with deltopectoral flaps. One of these patients died before the completion of reconstruction. In three other patients the reconstruction was performed with a tubed pectoralis major myocutaneous flap including one patient after a failed reconstruction with a jejunum segment. or fistula prevention we applied silicon stents in three patients and self-expanding Nitinol stents in three other patients. RESULTS: Of five successfully reconstructed patients two fed orally, one fed combined orally and via PEG and two fed via PEG. CONCLUSIONS: Summarizing our experiences the use of silicon tubes and nitinol stents has proved its worth. Experiences with a larger number of patients must be collected in the future.

Expression of Ca(2+)-activated K(+) channel subunits and splice variants in the rat cochlea.

The recently manifested important role of the Ca(2+)-activated K(+) channels, especially of the Slo gene-coded channels, for the cochlea function of the chicken raised the question of homolog expression in mammalian inner ear tissue. Molecular biological methods were used to demonstrate the expression of Ca(2+)-activated K(+) channel subunits and splice variants of the Slo gene in the rat organ of Corti. RT-PCR experiments for the detection of rat Slo alpha subunit mRNA revealed the presence of several already known splice variants including variants which appeared to be typical for the organ of Corti (+58 aa) and for the brain (+61 aa). To detect the accessory beta subunit we used Southern blot hybridization. Our data support the hypothesis that Ca(2+)-activated K(+) channel subunits (i.e. Slo variants) are also involved in the hearing of mammals in the organ of Corti.

Total implantation of the active hearing implant TICA for middle ear disease: a temporal bone study.

A subpopulation of hearing-impaired patients has conductive hearing loss that cannot be improved by classic tympanoplasty. Other patients have a mixed hearing loss and cannot be helped by present forms of ear surgery or by hearing aids. Possible help for some patients may come from current implantable hearing devices if these are modified for the patient's specific anatomic situation. The TICA LZ 3001 is a hearing implant for total implantation used to treat moderate to severe sensorineural hearing loss. Most patients who use it have a normal ossicular chain that allows coupling of the implant to the incus. The present temporal bone study demonstrates that the TICA can also be used in patients with an interrupted ossicular chain. If the incus long process shows a defect, the TICA may be coupled to the incus body, and connection between the stapes and the long process of the incus can be achieved with a commercially available titanium-angle prosthesis or liquid ionomeric cement. In cases of an absent incus, the coupling axis of the transducer may be coupled to the stapes head via a modified coupling element. With an absent stapes, the coupling axis may be coupled directly to the perilymph by a coupling element similar to a gold stapes prosthesis.

Computer-aided surgical planning for implantation of hearing aids based on CT data in a VR environment.

A study was undertaken to assess the feasibility of a preoperative fitting test for an implantable hearing aid in a virtual reality (VR) environment. High-resolution spiral computed tomography (CT) of the mastoid bone was performed, and the results of a mastoidectomy were simulated with manual segmentation on a standard medical workstation. CT was also performed on a temporal bone specimen obtained at real mastoidectomy, and the bone margins were segmented automatically with threshold-based techniques. A triangulated surface representation of the bone structures including the mastoid cavity was generated. These data as well as the computer-aided design (CAD) files of the medical devices were transferred into a VR environment. The CAD components of the hearing aid were manipulated to simulate the surgical implantation procedure. Merging CAD data of an implantable hearing aid with CT data of the temporal bone in a VR environment was shown to be a feasible method of providing three-dimensional information for the presurgical determination of fit and mountability. Advances in hardware and software are expected to improve the usability of this method. Although clinical studies are needed, these results may serve as an impetus for exploring the use of low-cost, widely available VR computer equipment in a potentially broad field of clinical applications.

[First implantation of a totally implantable electronic hearing aid in patients with inner ear hearing loss]. / Erste Implantationen eines vollständig implantierbaren elektronischen Hörsystems bei Patienten mit Innenohrschwerhörigkeit.

For the majority of patients with sensorineural hearing loss (SNHL) many available hearing aids often do not achieve satisfactory results. For these patients partially implantable hearing devices have been developed, allowing distortion-free hearing and speech intelligibility that may be superior to conventional hearing aids. The external parts of partial implants, however, may result in a patient's stigmatization. Furthermore, they do not use the acoustic properties of the external auditory canal. Recently, we published the successful development of the first totally implantable hearing device for the treatment of SNHL (HNO 46 [1998] 853-863). Here we report the first implantations of this unique, totally implantable electronic hearing system in patients with SNHL: Implex TICA LZ 3001. The implant microphone is implanted subcutaneously in the outer ear canal near the ear drum. The signal is processed by a digitally programmable multichannel audioprocessor located subcutaneously on the bony skull behind the ear. A piezoelectric transducer is coupled to the body of the incus and drives the ossicular chain by vibratory actions. Energy is provided by an implantable battery. Implanted patients describe hearing as being distortion-free and transparent. Speech intelligibility and the hearing of music are improved. Patients may achieve better speech discrimination, especially in the presence of background noise. The aid can be used during sports, including swimming. To our knowledge, this is the first report of the implantation of a totally implantable electronic hearing system in patients. These results encourage further implantations of the totally implantable hearing system in the course of an ongoing clinical study.

Tympanoplasty type II with ionomeric cement and titanium-gold-angle prostheses.

OBJECTIVE: The pronounced isolated erosion of the long incus process is a challenging situation during tympanoplasty. Here, we report two methods for reconstruction of the ossicular chain as tympanoplasty type II with the incus remaining in situ. (1) lonomeric cement is used, resulting in two characteristics: a direct link between stapes head and the long incus process is achieved. At the stapes head the link possesses a joint allowing physiological movements between incus and stapes. (2) Titanium-gold-angle prosthesis according to Plester were crimped to the long process of the incus and positioned onto the head of the stapes forming an articulation. STUDY DESIGN: Forty-five patients with missing long incus process underwent ossiculoplasty among which 41 patients were operated within a randomized, prospective clinical trial. For myringoplasty, the underlay technique with tragus perichondrium was used in all patients. SETTING: We investigated hospitalized patients. INTERVENTION: In 26 patients ossiculoplasty was performed as tympanoplasty type II, in 19 patients with incus interposition. MAIN OUTCOME MEASURE: The essential criterion was the postoperative air-bone-gap (dB). RESULTS: Incus interposition achieved less satisfactory results with an average remaining air-bone gap of 10-20 dB. By contrast, the two tympanoplasty type II procedures yielded average postoperative air-bone-gaps of 0-10 dB (p=0.0003 at 1 kHz; p=0.0028 at 4 kHz), thus reaching the "gold standard" of stapedotomy. The two type II procedures, however, were not equal. The angle prosthesis was restricted to cases with a sufficiently long incus process, whereas the cement-technique is also applicable, when only a short part of the long incus process remained. CONCLUSION: In the present study we show that in the case of a missing crus longum of the incus, a tympanoplasty type II achieved a statistically significant better hearing gain than an autograft interposition.

[A micromanipulator for intraoperative vibratory hearing assessment with an implantable hearing aid transducer]. / Ein Mikromanipulator für intraoperative vibratorische Hörprüfungen mit einem implantierbaren Hörgerätewandler.

First concepts of implantable hearing aids to be coupled to the ossicular chain are available for patients with combined or sensorineural hearing loss (SNHL). To ensure that hearing can be improved intraoperative coupling of a test transducer to the ossicular chain is mandatory for allowing surgical anatomy to be checked and vibratory hearing tests to be performed. To achieve this, the test transducer has to be held and positioned securely in situ for some minutes, avoiding risks for middle or inner ear structures. This is not possible using conventional surgical instruments. Thus, a micromanipulator to hold the test transducer during intraoperative hearing tests was developed. This surgical device allows the surgeon safe, risk-free, and controlled coupling of the test transducer to the ossicular chain with one axial and three rotational degrees of freedom. With the aid of a conventional ear retractor (2x2 prongs), the manipulator is fixed at the patient's ear. In conjunction with a piezoelectric test transducer, the manipulator was used in nine patients during local anesthesia. The test transducer is part of an electronic hearing implant (Tübingen implant) specifically designed for SNHL that may be coupled to a middle ear ossicle or the perilymph of the cochlea. The micromanipulator was easy to handle. It allowed accurate positioning of the test transducer in the ear and the desired coupling of the transducer's probe tip to the ossicular chain during auditory tests. According to the principles of integrated safety, the intraoperative risk of ossicular or inner ear injuries caused, for instance, by the patient's head movement is minimized. The design of the manipulator system is universal, also allowing its use for other electronic hearing implants or minimal invasive surgery after minor modifications.

[An osseointegrated micromanipulator as anchor for implantable hearing aid transducers. 1: Fitting to the surgical anatomy of the temporal bone and surgical technical properties]. / Ein osseointegrierter Mikromanipulator als Halterung für implantierbare Hörgerätewandler. Teil 1: Anpassung an die chirurgische Anatomie des Felsenbeins und operationstechnische Eigenschaften.

The first electronic implantable hearing aids for patients with hearing loss are coupled to the ossicular chain or perilymph during implantation and are now available. Our new Tübingen implant designed for sensorineural hearing loss (SNHL) is the combination of an implantable microphone and piezotransducer. To avoid hearing losses during implantation, the Tübingen piezotransducer will be (1) fixed to the mastoid cavity and (2) positioned to one of the ossicular target points. This can be done with a micromanipulator which will be implanted together with transducer and microphone in the mastoid cavity. The manipulator weights 0.7 g. With four degrees of freedom, it allows highly secure and safe positioning of the transducer's probe tip to the ossicular chain under close to stereotactic conditions. The main advantages of the present micromanipulator are (1) easy handling during surgery, (2) the transducer's precise positioning to the ossicular target point with sufficient degrees of freedom, and (3) the transducer's stable fixation in the mastoid cavity in the final position. Following integrated safety as the leading principle, ossicular or inner ear injuries caused, e.g., by the patient's head movement or unintentional manual contact by the surgeon, are minimized. The micromanipulator is, as it were, the surgeon's vibration-free "artificial hand". The manipulator's development and its optimization to the mastoid cavity by test implantation in 50 human temporal bones are shown in detail. While coupling the transducer to the body of the incus, transducer, microphone, and micromanipulator can be implanted into 76% of all mastoid cavities without protrusion. In the case of transducers coupling to the long process of the incus, the protrusion-free implantation rate of the above-mentioned three implant modules is 78%.

[Value of Schüller conventional roentgen diagnosis and computerized tomography of the temporal bone in preoperative diagnosis of the Tübingen implantable cochlear amplifier]. / Der Stellenwert der konventionellen Röntgendiagnostik nach Schüller sowie der Computer-tomographie des Felsenbeins bei der präoperativen Diagnostik des Tübinger implantierbaren Kochleaverstärkers.

Recently, the transducer and microphone of a cochlea amplifier implant (CAI) for the treatment of sensorineural cochlear hearing loss have been developed further for implantation into the mastoid cavity. At present, the University of Tuebingen implantable cochlea amplifier consists of an implantable microphone and an implantable piezoelectric transducer. It has been implanted into the first patients. Successful future application of this new implant depends on the suitable fit of the CAI within a patient's mastoid cavity. Using conventional X-ray and CT scans, we analyzed 50 cadaver specimens of the temporal bone before total mastoidectomy. After total mastoidectomy, the volume of the mastoid cavity was measured using CT scans and water volume determination. Finally, the CAI was implanted into those temporal bones that were large enough to house it. Our results demonstrate that the degree of pneumatization in the conventional Schüller X-ray is already a good parameter for preoperative evaluation.