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Biomedical subjects

T Lenarz

Publications and source records attributed to T Lenarz.

At least 19 recordsLinked to original sources
PubMed1996

[The Clarion cochlear implant--technical principles, initial clinical experiences and results].

BACKGROUND: Certain design characteristics of the Clarion device (Advanced Bionics Corp.) make it significantly different from other cochlear implant systems. It has a preformed electrode array to be placed closer to the modiolus, thus providing a more efficient coupling of the electrical signal to the auditory nerve; a telemetric function which permits the evaluation of the implant electronics; and two different speech processing strategies. The strategies are continuous interleaved sampling (CIS) and compressed analog (CA); both can be programmed into the same speech processor and alternatively selected by the patients, as they desire. The surgical procedure is only slightly different from the procedure familiar from the Nucleus system with the exception of a significantly larger cochleostomy. PATIENTS: The results of a series of speech tests designed to evaluate benefit in terms of speech understanding were administered to the first ten Clarion patients and compared to the results of a similar group of patients using the Nucleus system and the M Peak method. From a data-base of more than 300 Nucleus users, it was possible to select ten subjects who had near-equivalent data for onset of deafness, duration of deafness, and age at implantation (so-called matched pairs). In the majority of cases, etiology and course of deafness (progressive or sudden) could also be matched. RESULTS: It was found that the Clarion patients had higher test scores than the Nucleus patients after two weeks, three months, and six months after implantation. This positive experience with the Clarion device encouraged us to continue implanting this system in patients. As of September 1995, 106 patients (including 35 children between the ages of two and fourteen) are currently enrolled in the study. CONCLUSIONS: A final assessment of results with the Clarion implant is not possible because of the short follow-up. In any case, it appears that the patients with this implant system achieve faster open-set speech understanding and that it is accomplished with less effort in programming and shorter rehabilitation time.

Adolescent↗
PubMed1996

[Tooth discoloration as a rare complication of septorhinoplasty].

BACKGROUND: Surgeons should thoroughly consider the clinical implications of elective surgery such as septorhinoplasty for functional and cosmetic improvement of the appearance of the nose. Complications may jeopardize the intended result of this surgery. CASE REPORT: We report on the rare complication of devitalization of two incisors in the maxilla with disturbing discoloration after performing a septorhinoplasty in a 23-year-old woman. The patient underwent a serial hydrogen peroxide bleaching and a root canal procedure. CONCLUSION: The osteotomy of a huge basal crista that compromised neurovascular dental supply could be a possible mechanism of this event. Even though such a complication after septorhinoplasty is extremely rare, patients should be informed of this eventually prior to surgery, if only for legal reasons.

Adult↗
PubMed1996

[Distant metastasis of renal cell carcinomas to the head-neck area].

BACKGROUND: Metastases of hypernephroma to the head and neck, especially to the larynx, are rare occurrences. PATIENTS: We report on two cases with solitary spread in the head and neck. A 73-year-old woman who underwent nephrectomy because of a hypernephroma six years ago had a manifestation in the right false vocal cord, which was resected by laser surgery. The specimen of the strumectomy in the other patient revealed a metastasis of an asymptomatic hypernephroma to the thyroid gland and finally led to correct diagnosis of the primary tumor. RESULTS: The female patient refused any further treatment and died of cachexia with tumor dissemination four months later. The other patient is still living with a local recurrence after palliative irradiation and administration of interleukin-2 and alpha-interferon. CONCLUSIONS: In absence of other tumor manifestations, choosing an adequate therapy can be difficult because of the long survival rates in some patients even after hematogenous spread and the unpredictable behavior of this malignancy.

Aged↗
PubMed1996

[Cochlear implant in inner ear abnormalities and footplate malformation].

BACKGROUND: Malformations of the cochlea can cause deafness and otogenic meningitis. Cochlear implantation in children with such malformations, which are sometimes quite complex, require special attention before, during and after surgery. PATIENT: The concept developed for these patients at Hannover Medical School is illustrated in a patient with severe bilateral inner ear malformation and bilateral stapes defect. Implantation of a cochlear implant was performed in this 2-year-old girl. A large endostal sack originating from the inner ear, which had caused meningitis twice, was observed in the right middle ear. Both ears had to be obliterated to prevent recurrent meningitis. RESULTS: The child had no post-operative problems and the initial rehabilitation efforts have been successful. The immediate and differentiated reactions to stimulation are very encouraging. This article briefly summaries all diagnostic and therapeutic procedures established over the last three years at Hannover Medical School in cases of implantation into a malformated cochlea. In particular, we describe perioperative radiology (CT scans, MRI and plain radiographs), facial nerve monitoring and intraoperative screening for "hearing sensations", details of surgical technique, and possible postoperative complications. CONCLUSIONS: Based on experience with 13 of these cases, we discuss the different aspects of implantation into a malformated cochlea. Given certain preconditions implantation into a malformated cochlea may be recommended.

Child, Preschool↗
PubMed1996

Expression of matrix-metalloproteinases and their inhibitors in human cholesteatomas.

The proteolytic erosion of the temporal bone is the key event in the pathognomonic course of cholesteatoma progression. The molecular mechanisms of bone resorption, endangering the ossicles, the inner ear, the facial nerve, large vessels or the brain, are not understood. Recently, a new family of proteolytic enzymes, the matrix-metalloproteinases (MMP's) has been described and identified, which seems to play a pivotal role in matrix- and bone homeostasis and inflammatory osteolytic diseases, e.g. osteoarthritis and periodontitis. These enzymes are sophisticatedly controlled by specific inhibitors and activation cascades. We investigated whether human cholesteatoma tissue expresses MMP's and MMP-inhibitors. By immunocytochemistry of cholesteatoma-cryosections, the expression of MMP-2 (72 kD collagenase), MMP-9 (92 kD collagenase), and MMP-3 (stromelysin-1) could be seen to be strictly confined to the basal and suprabasal cell layer of the cholesteatoma epithelium. The neutrophil collagenase (MMP-8) showed a more disseminated expression in the epithelium and the granulation tissue as well. The tissue inhibitor of metalloproteases, TIMP-1, could be detected only in very limited areas of the granulation tissue in a quite randomized manner. Therefore, a derailment in favor of proteolysis of the normally tightly controlled MMP-system might be postulated. The results indicate that members of the MMP-family could play an active role in the molecular mechanisms of cholesteatoma invasion into the temporal bone. This offers new insights into the pathophysiology of the disease and of potential therapeutic approaches.

Adolescent↗
PubMed1995

[Progressive hearing loss--pathophysiology, differential diagnosis, therapy].

Progressive sensorineural hearing loss (SNHL) is still a challenge to the otorhinolaryngologist. It can be solved only by a systematic and interdisciplinary approach to the patient and his disease. Most often an acute onset is observed with a non-linear, sometimes dramatic progress to chronicity and complete deafness. Cardiovascular and rheologic diseases, hereditary disorders, immunological phenomena, hormonal and metabolic derailments, infections, environmental causes like noise, ototoxic drugs and industrial substances and systemic maladies must be included in the diagnostic reflections. Otopathy is an idiopathic hearing loss which cannot be classed with the above mentioned disorders. Wherever possible a causal therapy should be carried out. Symptomatic therapeutic concepts include rheologic medications, corticosteroids or, with all reservation, cytotoxic drugs. Hearing aids should be prescribed in close relation to the dynamic deterioration of the hearing. The timely cochlear implant operation stands at the end of the therapeutic scale.

Cochlear Implants↗
PubMed1995

[Noninvasive assessment of intracochlear pressure. III. Case reports of patients with intracochlear hyper- and hypotension].

It was the scope of two previous papers to outline the basics and possible neurotological applications of the tympanic membrane displacement technique (TMD). The present paper is aimed at briefly reviewing five distinct cases where a sudden sensorineural hearing loss with/without tinnitus could be monitored by the TMD technique. These features include a sudden hearing loss upon lumbar puncture, the audiological manifestation of an internal hydrocephalus, stapes gusher and the round window rupture. All symptoms are based on a change in intracranial and intracochlear pressure which in turn leads to the manifestation of the previously unknown sensorineural hearing loss and/or tinnitus.

Adult↗
PubMed1995

[Standardization and quality assurance exemplified by tinnitus].

Quality management will become another discipline for intensive care and research for the physician. Therefore, the first step in this process will be the need for standardised evaluation criteria and case record forms for documentation, leading to effective quality assessment and control. Only this approach may promote our attempts to improve the quality of patient care. Tinnitus is, due to the lack of objective measurable parameters and a missing rational basis of therapy, up to now a "crux medicorum" for every involved person. In this paper we reproduce a case record form and a patient's questionnaire for patients suffering from tinnitus. The presented forms are based on a consensus conference concerning the evaluation of treatment regimens held at the Fourth International Tinnitus Seminar in Bordeaux in August 1991. Epidemiological data, collected with this questionnaire, are presented and analysed. In conclusion, the presented case record form will lead to a standardised evaluation of symptoms according to tinnitus and improve our understanding of concomitant disturbances in tinnitus sufferers. Furthermore, this form of evaluation and documentation will produce comparable data in different centres allowing a pooling of patients data and history. A comparison of clinical trials in which the items are collected by the procedure shown here will be facilitated and lead us to a new understanding in determining the causes of the disease and the outcome of different therapeutic regimens.

Adolescent↗
PubMed1995

[Carcinoma of the temporal bone--current diagnostic and therapeutic aspects].

BACKGROUND: Carcinoma of the external ear canal and the middle ear is a rather rare event and is especially seen in patients with chronic inflammatory ear disease. PATIENTS: Between 1993 and 1994, we treated seven patients with such a tumor, of which six proved to be a squamous cell carcinoma and one presumably adenocarcinoma. In three patients, the malignoma developed in a radical cavity of the ear and caused a facial palsy. Only two patients were without any discharge of the ear. Beside facial palsy, hemorrhagic otorrhea and otalgia were the leading symptoms. One patient presented with a bilateral painless swelling of the neck due to lymph node metastasis. Diagnosis was made by means of biopsy in only three patients and on the basis of a resected specimen after mastoidectomy in four patients. Angiography and computed tomography and magnetic resonance imaging studies were performed prior to treatment to determine the extent of the tumor. RESULTS: The tumor was resected by petrosectomy, parotidectomy, and neck dissection in 5 patients. Three times the margins of the histological specimen were free of tumor. Lymph node metastasis in the neck were seen in 5 cases, while distant metastasis did not occur. Two patients underwent primary irradiation, but a postoperative radiation therapy was performed five times. To date, three patients died after one year follow-up. CONCLUSIONS: Carcinoma of the temporal bone is a rare tumor, which can be treated only in case of early diagnosis.

Adenocarcinoma↗
PubMed1995

[Langerhans cell histiocytosis of the temporal bone].

BACKGROUND: The localized form of the Langerhans cell histiocytosis was referred to earlier as eosinophilic granuloma, which has the best prognosis of all histiocytosis syndromes concerning survival. The non-malignant proliferative disorder of the histiocytic system is still of unknown etiology. Characteristic radiographic signs are osteolytic lesions. PATIENT: We report on an otologic manifestation of a 20-year-old man's temporal bone, which developed three years after a successful treatment of an eosinophilic granuloma of the mandible. RESULTS: Surgery and low-dose irradiation led to a complete remission of the disease. Other manifestations of the disease were not detected until now. CONCLUSIONS: In the presence of chronic aural discharge, Langerhans cell histiocytosis must bei considered in differential diagnosis and a histopathological examination should be performed.

Adult↗