Biomedical subjects

W Gstöttner

Publications and source records attributed to W Gstöttner.

12 recordsLinked to original sources

PubMed1999

[Interdisciplinary surgical treatment of anterior skull base tumors].

OBJECTIVES: We present our clinical experiences regarding interdisciplinary surgical treatment of anterior skull base tumours and evaluate postoperative results. METHODS: Fifty-seven patients (25 male, 32 female) with benign and malignant neoplasms involving the anterior skull base were retrospectively reviewed. In all cases tumour resection was carried out by an interdisciplinary rhino-neuro-surgical skull base operating team. Forty-three of 57 patients (75.4%) underwent common transbasal tumour resection and 11 (19.3%) were operated on from an extended transbasal approach. An extensive transbasal approach for tumour resection was used in 3 patients (5.3%). Postoperative mortality and morbidity were evaluated over a period of 6 months. RESULTS: In all 57 patients a good access to the frontal fossa and the sinuses was achieved. By means of the transbasal approaches, one-step tumour removal was possible in all cases. Tumor diameter ranged fom 12 mm to 114 mm. Even tumours extending as far as the hard palate required no additional transfacial procedures. Surgical mortality was 3.5%. Permanent postoperative complications were noted in 4 cases (7.02%) and transient postoperative complications in 7 (12.28%). CONCLUSION: In dealing with anterior skull base tumours, interdisciplinary surgical procedures using transbasal approaches provide a satisfactory outcome at a low rate of postoperative complications. When transbasal approaches are applied, no additional transfacial skull base exposure using midfacial incisions is required.

Adult↗

PubMed1998

[Function preserving surgical therapy of head-neck tumors with the CO2 laser].

The use of microscopically controlled laser surgery to treat tumors of the upper aerodigestive tract has as a function maintaining form of treatment gained significance. It is an alternative to conventional surgery, which often makes organ removal necessary. We report on our experience with 85 patients who underwent a laser surgical resection of malignomas of the upper aerodigestive tract. The aim of transoral laser surgery is a histologically confirmed radical tumor resection. Tumor resection can be individually adapted according to the tumor extent. An unnecessary resection of cartilage and muscles can be avoided. Provided the appropriate indication is given, laser surgery yields good oncologic and excellent functional results.

Adult↗

PubMed1997

Diagnostic and therapeutic approaches to carotid body tumors. Review of 24 patients.

OBJECTIVE: To determine the clinical characteristics of carotid body tumors to define better a standardized proceeding in the management of carotid body tumors. DESIGN: Retrospective survey. Duration of postoperative follow-up was 4 months to 16 years (median, 57 months). SETTING: Institutional, tertiary care medical center. PATIENTS: Consecutive sample of 24 patients (10 men and 14 women) with 28 carotid body tumors treated in the University of Vienna (Austria) General Hospital in 35 years. INTERVENTIONS: Surgical resection, preoperative embolization. MAIN OUTCOME MEASURES: Initial signs, duration of symptoms, extension of the tumors, methods of investigations, and treatment modality, with special respect to the operative technique. RESULTS: Doppler color flow imaging and angiography provided essential mainstays for definite diagnosis. Computed tomography and magnetic resonance imaging contributed additional information about tumor extension. Nineteen patients (79%) underwent surgical resection of 22 tumors, 8 (42%) after preoperative embolization. There were no perioperative deaths. Hemiplegia occurred in 1 patient, and cranial nerve palsy occurred in 5 patients. Tumor recurrence was observed in 3 patients. Five patients refused surgery or tumors were unresectable. CONCLUSIONS: Our standard diagnostic procedure consists of establishing diagnosis by Doppler color flow sonography, angiography for detailing the vascularization of the tumor, and selective embolization to enable safer surgery with less bleeding. Early surgery is recommended to minimize major risks.

Adult↗

PubMed1997

[MRI of the regions of the inner ear and cerebellopontine angle using a 3D T2-weighted turbo spin-echo sequence. Comparison with conventional 2D T2-weighted turbo spin-echo sequences and T1-weighted spin-echo sequences].

PURPOSE: To assess the value of a three-dimensional (3D) T2-weighted turbo spin-echo sequence (3D T2-TSE) in comparison to conventional two-dimensional (2D) T2-weighted TSE and unenhanced and enhanced T1-weighted spin-echo sequences (SE) in imaging anatomic structures and pathologic changes of the inner ear and cerebellopontine angle. PATIENTS AND METHODS: The inner ear and cerebellopontine angle were investigated by MRI in three healthy volunteers and 18 patients performing a 2D T2-weighted turbo spin-echo sequence and a 3D T2-TSE in the axial plane. In the patient study, 2D T1-weighted SE sequences both before and after the i.v. injection of gadopentetate dimeglumine in both the axial and coronal plane were performed in addition. RESULTS: Only the 3D T2-TSE enabled an accurate imaging of the anatomic structures. In cases of pathology, the 3D T2-TSE provided additional information to the performed 2D sequences. The combination of the 3D T2-TSE with unenhanced and enhanced 2D T1-weighted SE enabled the most accurate diagnosis in cases of pathology. CONCLUSIONS: Accurate depiction of anatomic structures of the inner ear and cerebellopontine angle could be obtained by 3D T2-TSE only. The most accurate diagnosis in cases of pathology was provided by the combination of the 3D T2-TSE with unenhanced and enhanced 2D T1-weighted spin-echo sequences.

Adult↗

PubMed1997

[Cochleoscopy].

Explore the source record for details and available documents.

Animals↗

PubMed1997

Optimization of channel number and stimulation rate for the fast continuous interleaved sampling strategy in the COMBI 40+.

OBJECTIVE: To investigate the interrelation between number of channels and stimulation rate in the continuous interleaved sampling strategy (CIS). SUBJECTS AND METHODS: Three of the first recipients of the new COMBI 40+ cochlear implant participated in consonant, vowel, number, and sentence tests. Speech understanding was evaluated for different combinations of number of active channels from two to twelve and stimulation rate per channel between 1,515 and 9,090 pulses per second. RESULTS: The results indicate that the optimum number of active channels is not necessarily the maximum number of usable channels.

Adult↗

PubMed1996

Transpalatine excision of a cavernous hemangioma of the infratemporal fossa.

Hemangiomas of the head and neck region can represent a therapeutic challenge depending on their size, location and symptoms. We report a case of a 40-year-old woman who presented with a 2-cm encapsulated cavernous hemangioma in the infratemporal fossa (ITF). Extensive workup included CT, MRI and angiography. A transoral/transpalatine approach avoiding osteotomy was used for surgical excision. After an unremarkable postoperative course the patient has remained disease-free after a 2-year follow-up period. We suggest this surgical approach as an alternative in carefully selected cases of circumscribed small, benign lesions of the ITF.

Adult↗

PubMed1990

Optimizing of electroneuronography of the facial nerve.

The amplitude ratio between the paretic and the normal side as determined by electroneuronography is used as a basis for estimating the prognosis of facial palsy. Several methods have been described of placing the surface electrodes and of finding the supramaximal impulse strength. We investigated 16 normal test persons with the aim (1) of optimizing the procedure of neuronography with regard to the possible variations of electrode placement and stimulus intensity and (2) of finding out the right/left difference in normal test subjects. Following our results, the best positions of the recording electrodes are the nasal alae. Even under these most favorable test conditions we found an average side difference of the bilaterally recorded electroneurograms of normal test persons of 22%.

Adult↗

PubMed1987

[Vestibulocochlear anastomosis in the brain stem of the guinea pig. Preliminary report].

A conspicuous fibre bundle running through the vestibular nuclear complex into the cochlear nucleus could be detected after tracing the superior vestibular nerve branch and the macula sacculi of the guinea pig with HRP (horseradish peroxidase). Considering certain electrophysiological findings, it is quite reasonable to believe that these fibres are indeed primary vestibular afferent fibres in synaptic contact with secondary cochlear neurons.

Afferent Pathways↗

PubMedDate not supplied

MR compatibility of Med EL cochlear implants: clinical testing at 1.0 T.

PURPOSE: Our aim was to evaluate the MR compatibility of Med EL cochlear implants by performing in vitro and in vivo tests. METHOD: All experiments were done on a 1.0 T machine. Potential movement of the cochlear electrode relative to a scale was recorded. Potential dislodgment of the magnetic receiver coil was evaluated with the coil fixed to the retroauricular skin of a volunteer. Temperature changes were measured with temperature sensors fixed to the electrode, performing standard MR sequences. In 11 patients, MRI of the brain was performed 1 day before explantation of the devices using standard MR sequences. Testing of the auditory abilities was done before and after the examination. All explanted devices were assessed for function. RESULTS: There was no detectable movement of the electrode or the receiver coil nor any temperature change. There were no adverse events for the patients. All 11 explanted cochlear implants retained their function. CONCLUSION: Med EL cochlear implants are not a firm contraindication for MRI.

Artifacts↗

PubMedDate not supplied

Speech understanding in quiet and in noise with the CIS speech coding strategy (MED-EL Combi-40) compared to the multipeak and spectral peak strategies (nucleus).

This study compares sentence understanding in quiet and in noise with 3 different speech coding strategies for cochlear implants. The results show that the spectral-peak (SPEAK) and continuous-interleaved-sampling (CIS) coding strategies, based on spectral signal analysis, allow for better speech understanding in quiet as well as in noise, than the multipeak (MPEAK) coding strategy, which relys on speech feature extraction. In the intrasubject comparison of the MPEAK and SPEAK strategies, the SPEAK coding strategy provided a considerable improvement in quiet and in noise for the majority of patients using the Nucleus 22 Mini-implant. In the intersubject comparisons, the mean results in noise with the CIS strategy were superior to both the MPEAK and the SPEAK strategies. The difference was greatest for the most difficult tests in noise. Understanding in noise was least reduced for the CIS strategy. Understanding in quiet was not significantly different between the CIS and the SPEAK strategies; both strategies were significantly better than the MPEAK strategy in quiet. These results are still preliminary, due to the relatively small number of patients and the great inherent intersubject variability of results.

Adolescent↗

PubMedDate not supplied

Evaluation of performance with the COMBI40 cochlear implant in adults: a multicentric clinical study.

The present multicentric clinical study involves 19 centres, 16 of them in German-speaking countries, 1 British, 1 Polish and 1 Hungarian. 60 postlingually deafened adults with a mean age of 47.5 years (20-70) and mean duration of deafness of 5.3 years (0.5-20) have been evaluated with the MED-EL COMBI 40 cochlear implant which implements a high-rate continuous-interleaved-sampling strategy with 8 channels. Safety and effectiveness data have been collected. Speech perception tests include a 16-consonant, an 8-vowel, a sentence and a monosyllabic-word test in all languages and a 2-digit figure test in all languages but English. Test intervals are 1, 3, 6 months and 1 year after first fitting. 41 of the 60 postlingually deafened adult study patients have completed their 6-month evaluation. While their pre-operative monosyllabic-word score was 0%, their mean monosyllabic-word score 6 months after first fitting was 48% (8-90) with a median of 50%. The mean sentence understanding was 84% (24-100) with a median of 90%. The respective values for the 1-year evaluations with 25 patients are a mean of 50% (5-85), with a median of 60% for the monosyllables and a mean of 89% (30-100), with a median of 97%, for the sentences.

Adult↗