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Biomedical subjects

T Lenarz

Publications and source records attributed to T Lenarz.

At least 91 records · Page 5Linked to original sources
PubMed1998

Acute apnea caused by an epiglottic cyst.

A life threatening complication in the course of routine sedation in a 5 year old child is reported in a case study. A retention cyst of the epiglottis was found to be responsible for obstruction of the larynx leading to acute apnea. The patient history revealed recurrent episodes of stridor previously diagnosed and treated as acute laryngotracheobronchitis as well as border line psychomotoric retardation. Cerebral magnetic resonance imaging was performed for neuroradiological evaluation. After administration of sedation the child presented with stridor and acute apnea. Emergency orotracheal intubation could prevent tracheotomy but was complicated by the unexpected presence of a tumor at the base of the tongue. Further evaluation revealed a large epiglottic cyst. After endoscopic removal of the cyst no further episodes of apnea or stridor were noted.

Acute Disease↗
PubMed1998

[Diagnosis and therapy of tinnitus].

INTRODUCTION: Tinnitus is still one of the most frequent symptoms encountered by the otorhinolaryngologist. Diagnosis and therapy present high demands due to the complex etiology and secondary symptoms. PATHOPHYSIOLOGY: In contrast to objective ear ringing with a physical sound source near the ear, tinnitus is faulty coding within the auditory system. Damage due to all kinds of causes can lead to a change of spontaneous activity in the auditory system. The result is a subjective auditory impression which is increased by further learning processes. DIAGNOSTICS: The aim of otorhinolaryngologic and especially audiologic diagnostic studies is to find the cause of the tinnitus. Modern methods for the objectivation of tinnitus are still experimental. The psychosomatic diagnostic studies evaluate secondary symptoms. THERAPY: Acute tinnitus is treated like sudden deafness. For chronic forms, the analysis of the causes is particularly important for developing an individual consultation and therapy plan. Providing information of the patient is the first step for a sensible treatment of the symptoms. The retraining therapy represents a learning process to reduce subjective symptoms, inconvenience, and loudness. Supportive therapy includes the use of instrumentation and medication. CONCLUSION: Acute tinnitus is often curable. However, only palliative treatment is available for chronic tinnitus. The otorhinolaryngologist plays a crucial role in the management of the disorder.

Diagnosis, Differential↗
PubMed1998

[The Vibrant Soundbridge System: a new kind of hearing aid for sensorineural hearing loss. 1: Function and initial clinical experiences].

INTRODUCTION: Patients suffering from moderate to severe cochlear hearing impairment can not be considered for cochlear implantation on account of their relatively good residual hearing. Conventional hearing aids, on the other hand, have considerable disadvantages which clearly limit the benefit for these patients, e.g. feedback, sound distortion, unfavorable conditions for frequency transfer, occlusion, and recurrent infections of the auditory canal. In addition, many patients complain about a poor speech intelligibility in noise. VIBRANT SOUNDBRIDGE HEARING PROSTHESIS: Implantable hearing aids offer a new approach for improved auditory rehabilitation. The Vibrant Soundbridge system is based on an electromagnetic system, which is linked directly to the intact ossicular chain. Due to the high sound quality and the high frequency characteristic this system is ideally suited for the above-mentioned patient group. The usual disadvantages of conventional hearing aids can be avoided. Externally visible is merely the audio processor, which is worn in the retroauricular area and covered by hair. This processor transfers data and power via magnetic attachment transcutaneously. PATIENT POOL: During a European multicenter clinical study, 19 patients were implanted at MHH since February 1997. No significant complications occurred. RESULTS: In all patients, postoperative unaided pure tone threshold was unaltered in comparison with the preoperative recordings. The use of the audio processor leads to a significant functional gain, particularly in the high frequencies. The patients report about undistorted hearing resulting in a better speech understanding even in situations with loud background noise. CONCLUSION: The preliminary results show a promising new approach to the use of hearing prostheses for patients suffering from moderate to severe sensorineural hearing loss.

Audiometry, Pure-Tone↗
PubMed1998

[Development and clinical testing of a non-magnetic cochlear implant. Preliminary experimental studies and surgical concept. Results in the first 10 patients].

BACKGROUND: To ensure good transmission of electromagnetic signals from the speech processor to the internal cochlear stimulator (ICS) in cochlear implants, exact alignment of the external transmitter coil over the receiver coil of the ICS is necessary. Usually this is achieved by two magnets: one implanted within the ICS, the other one integrated into the transmitter coil of the external headset. Although this principle works, there are some serious problems with the implanted magnet. The most serious of these is that it renders MRI studies potentially hazardous or impossible, or at least compromises image quality. METHOD AND RESULTS: We developed a method to eliminate the magnet. The method requires varying the implantation technique and using a special headset. The technique is easy to perform, and the headset is suitable for series production. Experience with our first patients revealed the coil alignment to be remarkably stable, even more than in patients with a cochlear implant equipped with a magnet. Results of the first ten patients are presented. DISCUSSION: Aside from eliminating the magnet, we attempted to optimize the acoustic properties of the headset. This resulted in design changes such as repositioning the microphone. Further improvements such as integration of telephone coils and special sockets to connect peripheral appliances can easily be implemented in our special headset.

Adult↗
PubMed1998

[Otogenic brain abscess].

BACKGROUND: Otogenic complications are rare but typical following acute or chronic ear infections like mastoiditis and cholesteatoma. A life-threatening sequela is the otogenic brain abscess located in the temporal lobe or cerebellum. PATIENTS: At the ENT Department of the Medical University of Hannover/Germany we treated 8 patients suffering from otogenic brain abscesses in the temporal lobe during the last three years. The average age of the 6 male and 2 female patients was 48 years. In 5 patients the abscess developed due to a cholesteatoma with superinfection. Three cases showed acute mastoiditis. All patients were operated using an otosurgical retroauricular approach, in five cases a classical radical mastoidectomy was performed. In two cases the abscess was reached via mastoidal approach and was subsequently drained. In two other cases the abscess was drained some days later by neurosurgical approach due to increased neurological symptoms. The other patients were treated with high-dosed antibiotics under regular clinical and radiological control. RESULTS: In 7 cases complete regression of the abscess was achieved. Five patients were discharged without further otological or central-nervous problems. One female patient developed severe meningitis with generalized thrombosis of the central blood sinus system and died in central circulatory failure. Two other patients developed a moderate psychopathologic syndrome and were admitted to rehabilitation institutions. CONCLUSIONS: The analysis of our patients shows that otogenic brain abscesses should be regarded especially as a severe complication of the untreated cholesteatoma. It is important to use modern imaging modalities like computer tomography or MRI for early detection of the intracerebral lesion and to perform an early otosurgical intervention. Under antibiotics and CT control, healing of this severe complication can be achieved in most cases. However, the danger of acute and chronic ear diseases has to be kept in mind in all medical disciplines.

Adult↗
PubMed1998

Fibroinflammatory pseudotumor of the temporal bone.

Chronic inflammatory tumor-like lesions of the temporal bone represent a difficult clinical task for the skull base surgeon. Their osteolytic aggressiveness endangers vital structures and may not be controlled by surgery alone. We present the course of four cases of fibroinflammatory pseudotumor of the temporal bone which were treated by a combined approach of skull base surgery and chemotherapy. Three patients were deafened by the disease and underwent several operafive measures. One patient was lost, most likely due to an arrosive bleeding of the internal carotid artery. The chronic and recurrent process could only be stopped by petrosectomy, followed by antiproliferative chemotherapy. Two patients were subsequently provided with a cochlear implant. The differential diagnosis, diagnostic, and operative options of this rare but severe disease are discussed.

Case Reports↗
PubMed1998

Cochlear implants: selection criteria and shifting borders.

Cochlear implants have proven to be effective and reliable in postlingually deaf adults. This is also true for congenitally deaf and perilingually deaf children up to the age of six years. Due to the increasing experience, the improvement of implant technology and the proven reliability the selection criteria are broadened with shifting borders. The main extensions are related to age, additional handicaps, residual hearing and special etiologies of deafness. Increasing evidence shows that very early implantation results in better performance and better hearing and speech development. Near-normal language acquisition can be achieved in children implanted under the age of four. Additional handicaps do not automatically exclude a candidate from cochlear implantation. A case-to-case decision has to be made based on additional diagnostics and the experience of the implant centre. A list of suitable handicaps is provided. Severely hearing impaired patients may also be considered for cochlear implantation if their residual hearing provides no benefit for speech discrimination. The same holds true for children. Cochlear implantation in obliterated cochleae and inner ear malformation requires a special surgical technique and special electrode arrays. In this way even difficult cases can be managed with remarkable outcome. Over all, the selection criteria have been broadened with increasing experience and technological improvement. This development may continue and the borderline between hearing aids and cochlear implants will shift further towards severe hearing loss. However, the basis for success still remains good rehabilitation, a team approach and the willingness of the patient to undergo the whole process of cochlear implantation.

Adult↗
PubMed1998

Pediatric cochlear implantation in cochlear malformations.

OBJECTIVE: This study aimed to present relevant information about pediatric cochlear implantation in malformed cochleas based on the experience gathered with 12 implanted children. STUDY DESIGN: A retrospective analysis was performed. SETTING: All patients were diagnosed and implanted at the Medical University of Hannover. Medical check-ups were performed regularly. The rehabilitation concept was developed by the Cochlear Implant Center of Hannover. PATIENTS: All children were female and were between 2 and 13 years of age at the time of implantation, with the average age being 4 years and 2 months. Only patients who were younger than 14 years of age and implanted between September 1992 and October 1995 were evaluated. INTERVENTION: Diagnostic computed tomographic scans including three-dimensional reconstructions and magnetic resonance imaging images were performed. In all cases, Nucleus devices (Mini 22 or 20 + 2) were implanted. Medical University of Hannover standard surgical technique was used, although in most cases, facial nerve monitoring and electrically evoked auditory brain stem responses were additionally recorded. Total or partial obliteration of the middle ear had occurred in two cases. An anteroposterior approach was used four times. The implantation was followed by the standard rehabilitation procedure for children. RESULTS: No serious complications occurred. All children responded to acoustic stimuli and showed improvement in their speech production. However, one autistic child performed poorly, and for another child suffering from a CHARGE syndrome, results still are pending. CONCLUSIONS: Given suitable preconditions, cochlear implantation is feasible with an acceptable risk of complications. Implantation appears to be beneficial in most cases with cochlear malformations provided that eighth nerve and cochlear lumen are present.

Adolescent↗
PubMed1998

[Myoclonus].

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed1997

[Diagnosis and therapy of lymphoid tumors of the orbits].

For the evaluation of neoplastic orbital lesions an interdisciplinary concept is crucial and includes modern imaging techniques as well as rhinosurgical approaches to the orbit. During a 14-year period 6 primary malignant orbital lymphomas and 9 cases of orbital pseudotumors were managed at our department. In most of the cases an exophthalmus with painful swelling of the eyelids, diplopia and a loss of vision were the clinical symptoms. Imaging using CT or MRI revealed homogeneous tissue formations that could not be clearly demarcated from adjacent orbital structures. By a rhinosurgical approach a biopsy was performed of each lesion without surgical complications. Following diagnosis the localized malignant lymphomas of the orbit were irradiated. In one patient systemic spread of tumor required multi-drug chemotherapy. Two patients died as the result of the sequleae of disseminated plasmocytomas. Patients with orbital pseudotumors were treated with systemic steroids. Two patients were also irradiated. No malignant transformation of any orbital pseudotumor was observed in this series. Our experiences show that careful histological evaluation of lymphoid orbital masses is necessary for correct diagnosis, especially since this has great impact on treatment and prognosis. Depending on the localization of a lesion medial orbitotomy by a rhinosurgical approach has proven to be a safe method for performing a biopsy or extirpating tumor.

Adult↗
PubMed1997

[In vivo studies of a piezoelectric implantable hearing aid transducer in the cat].

Recently, we presented an implantable piezoelectrical hearing aid transducer. Its characteristics make it suitable for implantation in patients with sensorineural hearing loss. The transducer transmits micromechanical vibrations instead of sound into the hearing organ. Efficiency of the transducer implant was investigated in ten cat ears. After determining preoperative (acoustical) BERA threshold, the middle ear was opened and the piezoelectrical transducer coupled to various ossicles or the perilymph. BERA responses were recorded following stimulation of umbo, long incus process, stapes head, stapes foot plate, and vestibulum. By comparing the acoustical and mechanical threshold, a correlation was found between the stimulus level of acoustical and mechanical stimulation. An electrical transducer voltage of 1 Vrms was equivalent to sound-pressure levels between 100 and 128 dB SPL at the tympanic membrane. To judge hearing impression, stimulus-dependent latencies of the early acoustically and mechanically evoked potentials (waves P1 to P5) and their thresholds were analyzed. After coupling the piezoelectrical transducer to the long incus process, latencies corresponded well to stimulation. They were almost completely similar when the equivalent sound-pressure level of 100 dB SPL was achieved by the transducer voltage level.

Animals↗