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Biomedical subjects

U Fisch

Publications and source records attributed to U Fisch.

At least 19 recordsLinked to original sources
PubMed2002

Analysis of formulation and food effect on the absorption of metoclopramide.

OBJECTIVES: Assessment of the relative and absolute bioavailability of immediate release and sustained release formulations of metoclopramide. Assessment of the effect of a high-fat meal on the pharmacokinetics of sustained release metoclopramide. MATERIAL AND METHODS: In a balanced 4-way crossover study in 16 healthy male volunteers, a sustained release (SR) formulation of metoclopramide was compared with a solution for injection (A) and an immediate release tablet (B). The SR formulation was administered after a fasting period (C) as well as after a high-fat meal (D). A single dose of 30 mg metoclopramide was investigated in each treatment. Metoclopramide concentrations were determined by HPLC. RESULTS: The absolute bioavailability of the sustained release formulation (fasting state) was 58% and thus about 17% lower than the bioavailability of the immediate release formulation. Comparing the treatments C (sustained release, fasting state) and D (sustained release, high-fat meal) no significant influence of food on the absorption of sustained release metoclopramide could be detected.

Absorption↗
PubMed2001

Multicenter audiometric results with the Vibrant Soundbridge, a semi-implantable hearing device for sensorineural hearing impairment.

The Vibrant Soundbridge, a semi-implantable hearing device for subjects with moderate to severe sensorineural hearing impairment was introduced commercially. First audiologic results are presented on 63 patients from 10 European implant centers. Hearing loss was at 0.5, 1, 2, and 4 kHz varying between 43 and 81 dB HL. The patients used the analogue audio processor, type 302. Measured sound-field gain was compared with NAL-R target values. For most patients an acceptable agreement was found. There was a subgroup of patients, however, with relatively low gain. The results suggest that this was related to the suboptimal positioning and fixation of the transducer to the incus.

Audiometry, Speech↗
PubMed2001

Evaluation of eardrum laser doppler interferometry as a diagnostic tool.

OBJECTIVES: Laser Doppler interferometry (LDI) of the eardrum allows noncontact optical analysis of its vibrations in response to sound. Although LDI has been widely used in research, it has not yet been introduced into clinical practice as an adjunctive test for otological workup. The aim of this study was to evaluate LDI as a diagnostic tool in the clinical sphere. STUDY DESIGN: Prospective. METHODS: A measurement system was developed based on a commercially available scanning He-Ne laser Doppler interferometer. The study included 129 eardrums of 79 subjects that were divided into 3 groups: 1) normal subjects and 2) patients with sensorineural and 3) conductive hearing loss (HL). All the patients suffering from conductive HL underwent ossiculoplasty, which allowed confirmation of the final diagnosis, and patients were assigned accordingly to the subgroups malleus fixation, incus luxation, and stapes fixation. RESULTS: The modified LDI system allowed bilateral evaluation of a subject within 30 minutes. No significant difference between normal subjects and patients having sensorineural HL were found. However, it was possible to distinguish between normal subjects and patients with conductive HL. Furthermore, the system had the ability to differentiate between various middle ear diseases. These groups differed statistically significantly in terms of manubrium vibration amplitude and resonance frequency. In malleus fixation significant differences in tympanic membrane movement patterns were found. CONCLUSIONS: Our LDI is applicable in clinical otological practice and serves as a valuable addition to the routine audiological investigations for preoperative evaluation of the mobility and integrity of the ossicular chain.

Adult↗
PubMed2001

Is the Er:YAG laser damaging to inner ear function?

OBJECTIVE: To assess whether the use of the Er:YAG laser in middle ear surgery has negative effects on inner ear function. STUDY DESIGN: Prospective. PATIENTS: Forty-nine patients with a 4- to 18-month postoperative audiologic follow-up were included in the study (24 stapedotomies, 23 malleostapedotomies, 1 surgery for congenital ear atresia, and 1 tympanoplasty). Twenty patients with conventional stapedotomy formed a control group. RESULTS: No statistically significant differences in preoperative and postoperative bone conduction thresholds and no impairment of postoperative air conduction thresholds were found. There was no significant difference between the results of the laser and the conventional stapedotomy. In addition, no relevant correlation between applied laser energy and postoperative hearing results were found. In summary, the authors were unable to find a negative effect of the Er:YAG laser on inner ear function at the 4- to 18-month audiometric follow-up. CONCLUSION: The clinical use of the Er:YAG laser with the system used in this study poses no risk to inner ear function if the total amount of energy is kept within the limits applied in this study.

Adolescent↗
PubMed2001

Comparative electron microscopic study of the surface structure of gold, Teflon, and titanium stapes prostheses.

HYPOTHESIS: The goal of this study was to compare stapes prostheses of different materials with respect to their surface structures and to discuss their suitability for their use in stapes surgery. BACKGROUND: The surface condition of a stapes prosthesis plays an important role in relation to the type of membrane that forms between the stapes piston and the bony edge of the stapedotomy opening. The quality of this membrane in thickness and mobility is one of the determinants for postoperative hearing improvement. METHODS: The surface conditions of gold, Teflon/steel, Teflon/platinum, and titanium stapes prostheses were examined with a scanning electron microscope. The loop, shaft, and end of each prosthesis were studied. RESULTS: The gold piston was the smoothest of the four pistons examined. When it was cut with a scalpel, a very smooth surface was achieved at the end area. The Teflon piston had the roughest surface. However, when it was cut, a smooth surface with a parallel arrangement of fibers resulted. Its steel loop was the smoothest, followed by gold and platinum. The titanium shaft had a scaly surface, which remained when the end of the shaft was shortened. CONCLUSION: Because a certain roughness of the piston surface is necessary for the development of a stable membrane between the piston and the edge of the stapedotomy opening, the titanium prosthesis is considered to be the most suitable for stapes surgery of the three pistons examined.

Gold↗
PubMed2001

Malleostapedotomy in revision surgery for otosclerosis.

PURPOSE: The purpose of this study was to analyze the results of malleostapedotomy and to compare them with those of a conventional incus stapedotomy in a series of 82 consecutive surgical revisions in otosclerotic patients. MATERIALS AND METHODS: 82 consecutive revision stapes surgery cases over 5 years were evaluated. The preoperative and postoperative audiometric data of 80 (97.5%) of the patients were obtained. RESULTS: 71 of the patients underwent a functional revision procedure as malleostapedotomy (56, 79%) or as incus stapedotomy (15, 21%). The most common cause of failure of primary surgery was a displaced or malfunctioning prosthesis (86.2%). Pathologic changes of the oval window were found in 80% of the cases. Problems of the incus were identified in 80% and abnormality of the malleus in 48.6% of the cases. The functional success rate of malleostapedotomy (closure within 10 dB) was found to be higher than that of traditional incus stapedotomy (p < 0.05). Overclosure was seen in 12 patients (17%) and a significant sensorineural hearing loss in 2 patients (3%). There were no dead ears in this series. The postoperative hearing results after first revision surgery were better than those after multiple surgical procedures (p < 0.05). CONCLUSIONS: Malleostapedotomy yields better functional hearing results than incus stapedotomy in revision surgery for otosclerosis. The detection of many malleus fixations was the result of the systematic exposure of the anterior malleal process and ligament through an endaural approach with superior canaloplasty.

Adult↗
PubMed2001

Clinical experience with the Vibrant Soundbridge implant device.

OBJECTIVE: To evaluate the full degree and range of benefits provided by the Vibrant Soundbridge (VSB; Symphonix Devices, Inc., San Jose, CA, U.S.A.) and analyze pre-and postoperative results of audiologic tests. STUDY DESIGN: Single-subject study with each subject serving as his or her own control. SETTING: Multicenter clinical study conducted at 10 centers in Europe. PATIENTS: 47 patients who met the selection criteria for participation in the study. INTERVENTIONS: Implantation of the VSB direct-drive middle ear hearing device. MAIN OUTCOME MEASURES: Average change in unaided thresholds with the patient wearing headphones at each frequency pre-and postsurgery was measured. A mean threshold change less than 5 dB across all frequencies was considered clinically nonsignificant. RESULTS: 47 patients had successful surgery for implantation and fitting with the VSB device. CONCLUSION: The VSB is a new middle ear implant device that can be used safely in the treatment of patients with moderate to severe sensorineural hearing loss.

Acoustic Stimulation↗
PubMed2001

Intraoperative assessment of stapes movement.

A method is described that allows, for the first time, intraoperative vibration modes assessment of the acoustically stimulated stapes by means of scanning laser Doppler interferometry (LDI). The study was designed to answer the following questions: 1) Is LDI practical for taking measurements during surgery? 2) Are the results comparable to the findings in temporal bone preparations? and 3) Do the vibration characteristics of the stapes change after the posterior incudal ligament is detached from the incus? Seven patients with profound bilateral hearing loss who were undergoing cochlear implantation were included in the study. The measurement system was easily applicable for intraoperative measurements and allowed contact-free analysis with very high accuracy. No major differences in the results from the live human subjects and temporal bone preparations were observed. The stapes movement was predominantly pistonlike at the lower frequencies and became complex at higher frequencies. Sacrificing the posterior incudal ligament had no statistically significant effect on stapes vibration.

Acoustic Stimulation↗
PubMed2000

Conservative management of unilateral acoustic neuromas.

OBJECTIVE: The aim of this study was to analyze the natural course of unilateral acoustic neuromas and to evaluate the advantages and disadvantages of an initial conservative approach. METHODS: Between 1989 and 1994, 74 consecutive patients with the diagnosis of unilateral acoustic neuroma were evaluated at the Department of Otorhinolaryngology, University of Zurich. Their charts and magnetic resonance imaging scans were retrospectively analyzed regarding duration and type of symptoms, initial tumor size, tumor growth pattern, and audiometric data. RESULTS: Of the 74 tumors, 68.9% (51/74) did not grow during a mean follow-up of 35 months. Eight (16%) of these tumors had radiologically documented tumor regression. Twenty-three tumors did grow, 16 of them (70%) with a growth rate of <2 mm/year. There was a statistically significant correlation between the first-year and the total growth rate, indicating that the tumor's behavior in the first year is highly predictive of its subsequent growth pattern. Patients with progressive hearing loss as a first symptom had a significantly lower tumor growth than those presenting with tinnitus, sudden hearing loss, or dizziness. Patients with tumor growth showed a greater tendency for hearing loss, although this trend was significant only for isolated frequencies. In 12% of the cases (9/74), the initial conservative approach had to be abandoned in favor of surgery. CONCLUSION: Watchful expectation can be regarded as a safe approach for selected cases of acoustic neuromas. Surgery or irradiation is indicated in patients with proven growth of their tumors.

Adult↗
PubMed1999

An update on the surgical treatment of temporal bone paraganglioma.

In 1982, Fisch described his results for the surgical treatment of 74 paragangliomas of the temporal bone, 5 years after his description of the infratemporal fossa approaches (types A and B). This study reviews the subsequent experience of the Department of Otolaryngology-Head and Neck Surgery of the University of Zürich with more than 136 surgically treated cases of paraganglioma of the temporal bone and discusses our current therapy 20 years after the initial description. One hundred nineteen (90%) of the patients had advanced tumors (Fisch class C or C+D), and 81 (68%) had intracranial extension. Total tumor excision was possible in 109 (82%) patients. Subtotal excision was performed in 22 (17%) patients, 21 of whom had intradural tumor invasion. In these cases, the resection was limited not by actual tumor size but by the degree of intracranial intradural tumor extension. Partial tumor excision was undertaken in only 1 patient with a C4De2Di2 tumor. The success rate in preservation of function of the lower cranial nerves was encouraging. Of the 69 patients whose facial nerve status was followed post-operatively, 81% maintained Fisch grade 76 to 100% (House-Brackman grades I and II). Analysis of follow-up data ranging from 2 to 11 years demonstrated 98% disease-free survival when total tumor extirpation was possible. In the patients who underwent subtotal or partial surgical resection there has been no subsequent tumor growth detected by either clinical or neuroradiological evaluation. We have confirmed after more than 20 years of experience that the infratemporal fossa approaches are a safe, highly effective means of surgical management of paragangliomas of the temporal bone, allowing eradication or arrest of disease with minimal morbidity. Limited intradural surgical resection in cases of very extensive tumors can greatly benefit patients for whom complete excision is not an option.

Journal Article↗
PubMed1999

Long-term results of surgery for temporal bone paragangliomas.

OBJECTIVES: Assessment of the long-term results of surgery for temporal bone paragangliomas with special consideration of the patient's ability to cope with the functional deficits. STUDY DESIGN: Retrospective review of 36 patients who had undergone resection of a temporal bone paraganglioma 10 to 15 years previously. Assessment of the patients' subjective view of the functional outcome and quality of life by a questionnaire. METHODS: Clinical records were reviewed regarding size of tumor, technique of surgery, supportive therapy, and tumor recurrence. Patients were sent a 50-item questionnaire evaluating their quality of life and the preoperative and postoperative function of cranial nerves VII through XII. RESULTS: A complete tumor removal was achieved in 30 patients (83%). There was only one tumor recurrence. The major negative effects of surgery involved hearing and dysphagia, which deterioriated in 14 and 12 patients, respectively. Thirty-five of the 36 patients (97%) reported that, despite deterioration, the cranial nerve deficits were still acceptable. Seventy-five percent of the patients regained their preoperative quality of life and 97% returned to their previous occupation in 1 to 2 years. CONCLUSIONS: The otologic extradural approach allowed complete tumor removal in 83%, with minimal perioperative morbidity. No surgically induced central nervous system lesions occured. Tracheostomy was avoided and all patients resumed oral feeding. Full rehabilitation after removal of class C and CD paragangliomas may take 1 to 2 years. However, the fact that 97% of the patients finally resumed normal social life showed the ability of most patients to cope with the sequelae of surgery even in class C and CD paragangliomas.

Adaptation, Psychological↗
PubMed1999

Objective evaluation of normal facial function.

The aim of this investigation was the assessment of normal facial movements using the objective computer-assisted OSCAR method. Computerized black-and-white video images of 20 healthy volunteers were recorded with the face at rest, maximal wrinkling of the forehead, forced eye closure, and forced smiling. The mean regional symmetry index was found to be 91% (SD 6%; range 80% to 99%) for wrinkling of the forehead, 93% (SD 5%; range 82% to 100%) for forced eye closure, and 91% (SD 5%; range 79% to 98%) for maximal smiling. Clinical weighting gave a global symmetry index of 92% (SD 3%; range 88% to 96%). The presented results show that the physiological dynamic asymmetry of the normal face is 7% to 9%. No dominant facial side could be found. The comparison of the results obtained with the OSCAR method with those of the subjective House-Brackmann and Fisch grading systems showed that the physiological asymmetry of facial movements can only be accurately determined with a computer-assisted objective method.

Adult↗
PubMed1998

Cochlear implantation after subtotal petrosectomies.

Among cochlear implant candidates there are patients who have abnormal middle and/or inner-ear conditions that make them unsuitable for implantation. Insertion of a foreign body may also be contraindicated in the setting of an existing or potential intracranial communication, or when the ear is prone to infection. Five patients presented with such unfavorable conditions. These included a Mondini dysplasia with persistent cerebrospinal fluid leak, an atretic mastoid with meningocele, chronic otitis media, a transverse petrous bone fracture, and a temporal bone adenoma. All patients underwent subtotal petrosectomies and cochlear implantations. In four cases implantation was performed concomitantly with subtotal petrosectomy, while the remaining case required a two-stage procedure. No complications occurred. The technique is described in detail, and the cases and the indications for surgery are discussed. By obliterating and isolating the tympanomastoid cleft from the outer environment and utilizing the technique of subtotal petrosectomy, a broader spectrum of patients can now be implanted safely.

Adult↗
PubMed1998

Update on the infratemporal fossa approaches to nasopharyngeal angiofibroma.

OBJECTIVES: Review of preoperative evaluation, surgical management, and outcome of patients operated on for nasopharyngeal angiofibroma using lateral infratemporal fossa approaches. STUDY DESIGN: Retrospective review of 20 patients with either extensive (Fisch class IIIa to IVb, n = 17) or less massive (Fisch class II, n = 3) nasopharyngeal angiofibromas. Analysis of preoperative radiologic classification and angiography and description of indications and surgical techniques of the infratemporal fossa approaches types C and D. Evaluation of the surgical morbidity and radicality of tumor removal. METHODS: Clinical data were obtained from medical records from 1987 to 1994. Tumor classification, preoperative symptoms, type of surgery, and neuroradiologic and surgical complications were evaluated. The completeness of tumor removal was assessed using postoperative magnetic resonance imaging. RESULTS: Temporary visual disturbance or headache, or both, was seen in two of 20 patients after superselective tumor embolization, and further visual diminution was observed in one of six patients after balloon occlusion of the internal carotid artery. Radical resection was obtained in 80% of the cases. The infratemporal fossa type C approach was used in 16 of the cases, with type D approaches used in the other four. There were no deaths. The major morbidity was the conductive hearing loss associated with the type C approach. CONCLUSIONS: Preoperative embolization (and balloon occlusion in selected cases) remains an important adjunct with minimal morbidity. The lateral infratemporal fossa approaches yield a high rate of radical tumor removal (80%) and a low rate of recurrence (6%). If applicable, the type D approach avoids the conductive hearing loss but allows direct tumor access into the infratemporal and pterygopalatine fossae.

Adult↗
PubMed1998

Rate and extent of early axonal degeneration of the human facial nerve.

Electrophysiologic and histologic studies on a severed human facial nerve have shown that 1) response to stimulation by electroneuronography was lost on the sixth day following injury, 2) wallerian degeneration progressed in a nonuniform "front," leaving some of the distal stump axons still viable and responsive to intraoperative stimulation 2 days following injury, and 3) the extent of proximal retrograde degeneration was far greater than to the next node of Ranvier. These findings are discussed in light of the current knowledge regarding peripheral nerve degeneration, and explanations are suggested.

Adult↗
PubMed1998

Objective scaling of facial nerve function based on area analysis (OSCAR).

An objective scaling of facial nerve function based on area analysis (OSCAR) was developed using the variations of luminance produced by changes of facial expression. The presented method of scaling facial motions has the advantage of being continuous, objective, and reproducible. It is fast and simple to use.

Adult↗
PubMed1997

Multicentric eighth cranial nerve schwannoma.

To our knowledge, only 3 histopathologically proved cases of multicentric eighth cranial nerve schwannoma have been described in the literature since 1981. We describe a patient with 2 isolated eighth cranial nerve schwannomas arising separately from the left cochlea and internal auditory canal. These 2 tumors were diagnosed using magnetic resonance imaging prior to resection, and the diagnosis was further confirmed by intraoperative findings and histopathologic analysis. The genetic molecular basis and clinical features of this rare tumor have been overlooked. The value of the transotic approach for total tumor removal is emphasized.

Adult↗