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Biomedical subjects

N Marangos

Publications and source records attributed to N Marangos.

At least 19 recordsLinked to original sources
PubMed2001

Brainstem response in cerebellopontine angle tumors.

OBJECTIVE: To evaluate the auditory brainstem response (ABR) findings in cerebellopontine angle (CPA) tumors and focus on those with normal ABR results. STUDY DESIGN: This was a retrospective evaluation of ABR findings. All subjects with diagnosed CPA tumors who were referred for treatment were included. PATIENTS: All 309 patients with radiographically confirmed (computed tomography or magnetic resonance imaging [MRI]) CPA tumors (153 before 1993 and 156 after 1993). INTERVENTION: All patients underwent complete audiologic examination, electronystagmography, ABR testing, and ipsilateral transtympanic electrocochleography. All tumors were histologically confirmed. MAIN OUTCOME MEASURES: The patients were categorized according to ABR results (normal or pathologic findings or no response); according to histology (vestibular schwannomas or meningiomas); and according to tumor size by MRI (small, up to 15 mm; medium, 16-25 mm; large, 26-40 mm; and very large, over 40 mm). RESULTS: Normal ABR results were found in 18.4%; pathologic ABR results in 31.4%; and no response in 50.2%. Small vestibular schwannomas (under 15 mm) showed a higher incidence of normal ABR results (41.7%). CPA tumors with normal ABR results (n = 57) caused no hearing loss (n = 12), symmetrical hearing loss (n = 11), or ipsilateral hearing loss with Short Increment Sensitivity Index 100% and normal acoustic reflex (cochlear deafness, n = 34). Caloric response was normal in 59.7% of these tumors. CONCLUSION: Because validation of ABR as screening for acoustic tumors is based on diagnosed tumors, and because MRI allows detection of very small tumors, the incidence of normal ABR increases and its sensitivity would be expected to decrease. ABR is not sufficient for early detection of small CPA tumors.

Audiometry, Evoked Response↗
PubMed2000

Topodiagnosis of deafness: strategy for treatment of neurofibromatosis type 2.

Neurofibromatosis type 2 (NF2) causes bilateral hearing loss due to tumour growth in the cerebellopontine angle. We report the results of promontory testing and transtympanic electrocochleography on subjects with deafness due to NF2 referred for an auditory brainstem implant. All 19 ears tested revealed loss of cochlear microphonics. Nine ears (mainly without previous treatment) revealed auditory perception during promontory stimulation, indicating cochlear deafness. One of these subjects has been successfully provided with a cochlear implant. The other 10 ears (mainly after previous surgery) revealed negative promontory stimulation, indicating additional retrocochlear deafness. These findings indicate that neurofibromas initially cause a cochlear deafness, so that a cochlear implant can be used if the auditory nerve can be preserved. This option has to be considered in rehabilitating patients with bilateral tumours due to NF2.

Adolescent↗
PubMed2000

Surgical experiences in 58 cases using the Nucleus 22 multichannel auditory brainstem implant.

Patients with bilateral total deafness due to lesions of the vestibulocochlear nerve can be treated by electrical stimulation of the second auditory neuron. A 22-channel multi-electrode implant with transcutaneous transmission was developed that allows the selection of the most useful electrodes. Acoustic neuromas were removed from 49 out of 58 patients by ENT surgeons and neurosurgeons working in collaboration and using either a translabyrinthine or suboccipital approach. The central electroauditory prosthesis was implanted in the same procedure. Six patients were deaf after previous acoustic neuroma surgery without recurrence, three had diagnoses other than neurofibromatosis type 2 (NF2). There were no complications due to the implantation procedure. Side effects could be excluded by stimulation of the auditory electrodes alone. Most of the patients used their ABI daily. They reported perception of different sounds and frequencies, enhancement of lip-reading ability, and three of the patients were able to use the telephone.

Adolescent↗
PubMed2000

Stimulation of the cochlear nucleus with multichannel auditory brainstem implants and long-term results: Freiburg patients.

Since 1992 18 patients with bilateral retrocochlear deafness have been provided with a multichannel auditory brainstem implant (ABI). The surgical procedure implies tumour removal and ABI implantation in one stage. Most implantations were via the translabyrinthine approach. The long-term follow-up varied between nine and 80 months. In one case auditory perception could not be achieved and in a second case post-operative stimulation was not possible as the subject died due to lung emboli. In all the other cases auditory perception was achieved and only two subjects became non-users during the follow-up period. The presented long-term results suggest that deaf neurofibromatosis type 2 patients regain acoustic contact with the environment, enlarge their communication skills and improve their quality of life by using a multichannel auditory brainstem prosthesis.

Adolescent↗
PubMed1999

[Extended indications for cochlear implantation. The Freiburg results in patients with residual hearing].

The usual indication for a cochlear implant (CI) is acquired deafness in patients for whom conventional hearing aids are of no benefit. The question is whether CI is superior to the best conventional hearing aids for patients with some residual hearing, but who achieve only minimal speech recognition (< 30% in the Freiburg monosyllable word test at 70 dB (I) SPL) with optimal hearing aids. We report our experience with five patients with residual hearing who underwent cochlear implantation (Nucleus Mini 22 and 24) on the worse side. The patients were examined preoperatively and at 1, 6 and 12 months following activation of the implant. The Freiburg monosyllabic word test, the Göttingen sentence test and consonant recognition were used to assess postoperative results. All patients benefitted from CI when test scores were compared with preoperative ones. All patients achieved a score in the Freiburg monosyllabic word test of more than 60% at 70 dB (I) SPL 12 months post switch-on. Four patients achieved a score of more than 85% in the Göttingen sentence test. These results and the progress made in cochlear implant technology are an impetus to continue discussions of various considerations of criteria for cochlear implants and possibly extend these for patients with severe hearing impairment.

Adult↗
PubMed1999

[Objective auditory brainstem response threshold deficits in patients with cerebellopontine angle tumors].

The established criteria of auditory brainstem responses (ABR) such as JV latency, JI-V interpeak latency and interaural differences of latency or amplitude have been found to be sensitive for detecting tumors of the cerebellopontine angle if a response is present. However, the ABR can be absent in cases of acoustic neuromas because of desynchronization, even though pure-one audiometry indicates that responses should be present. This retrospective study compared the ABR and pure-tone thresholds in 234 cases with cerebellopontine angle tumors and a control group of 181 cases with sensory hearing losses in order to quantify threshold discrepancies. The average deficit of the objective ABR threshold (DOABRT) to the subjective pure-tone threshold for those frequencies between 1-6 kHz was 3.6 dB for the control group (ABR and pure tone thresholds very close) and 31.2 dB for the tumor group (ABR threshold much higher than the pure-tone threshold). ABR thresholds 30 dB higher than the high-frequency pure tone thresholds were found in 40.6% of the tumor group and in none of the control group. Thus, deficits of the ABR threshold >30 dB can be considered to be an additional criterion for detecting retrocochlear disease and increases ABR sensitivity for tumor detection even if responses are absent.

Adolescent↗
PubMed1999

[Management of large bilateral glomus jugulare tumors].

Bilateral glomus jugulare tumors are rare. However, their treatment should preserve not only the function of the facial nerve but also the caudal cranial nerves and the middle ears in order to avoid bilateral hearing losses. Further, venous cerebral drainage has to be ensured in order to avoid cerebral hypertension and hemorrhagic infarction after bilateral jugular ligations. In the case presented bilateral glomus jugulare tumors required super-selective angiography and embolization. Complete tumor removal on both sides was then possible by a transmastoid-transcervical approach without any further functional deteriorations. Middle ear function was preserved on both sides by temporary ventral translocation of the posterior wall of the auditory meatus. As the sigmoid sinus and internal jugular vein had been ligated during initial previous surgery, venous drainage was tested one year later by angiography and compression of the remaining internal jugular vein. A sufficient collateral circulation was found and permitted surgery on the second side.

Angiography↗
PubMed1999

Facial palsy after glomus jugulare tumour embolization.

Facial palsy after pre-operative embolization of glomus tumours is a rare complication. In our case, complete facial palsy occurred within four hours after embolization with polyvinyl alcohol foam. Three days later, embolization material was found in the perineural vessels of the facial nerve in its mastoidal segment. Six months after complete tumour removal, facial decompression with perineural incision, and steroid therapy, facial function recovered completely. In cases of embolization of both stylomastoid and branches of the middle meningeal artery with resorbable material, temporary facial palsy can occur.

Carotid Artery, Common↗
PubMed1999

Paraganglioma as a systemic syndrome: pitfalls and strategies.

Tumours of the neuroendocrine system in the head and neck region are mostly paragangliomas of the glomus tympanicum or jugulare, or of the carotid body. The majority of these tumours are benign, and the coexistence of multiple paragangliomas seems to be rare. Pre-operative embolization and surgery are regarded as primary therapy for these tumours. The treatment regimen in any patient depends on age, general health, hearing status and the function of the lower cranial nerves. Several presentations are possible in which paragangliomas occur as systemic disease. 1. Paragangliomas may occur bilaterally, or, in rare cases, in multiple areas. Pre-operative bilateral angiography is of utmost importance. In case of multicentricity, it might be necessary to proceed without, or just with, unilateral surgery for preservation of adjacent structures. In surgery of jugular vein paraganglioma, we usually perform a modified transmastoidal and transcervical approach with preservation of middle-ear structures and the ossicles. As an alternative or supplement to surgery, radiotherapy or definitive embolization may be used in the treatment of paragangliomas. 2. Paragangliomas may occur as multiple endocrine neoplasia (MEN) syndrome combined with medullary thyroid gland carcinoma, and, facultatively, pheochromocytoma. In these cases, endocrinological examination and magnetic resonance imaging (MRI) of the adrenal region, the thorax and the neck are required for an adequate therapeutic strategy. As MEN may be inherited, family history should be evaluated. 3. Paragangliomas can became malignant and metastasize. Thus, cervical lymph node metastases or distant metastases may occur. We recommend the removal of all ipsilateral lymph nodes and their histological examination.

Adult↗
PubMed1999

[Value of B-image ultrasound in patients with carcinomas of the upper aerodigestive tract and N0 lymph node stage].

BACKGROUND: The wait-and-see policy in patients with a N0 neck stage is not common. PATIENTS AND METHOD: One hundred twenty-one patients with a pT1 or pT2 carcinoma of the upper aerodigestive tract and a N0 neck stage in ultrasound studies underwent transoral laser microsurgery without neck dissection or radiation therapy. In these patients the probability of survival and local or regionals recurrence were analyzed in a follow-up period of 18 to 36 months. RESULTS: Thirty patients in whom cervical lymph nodes were detected in ultrasound studies, underwent a curative neck dissection procedure. In 8 of these 30 patients, lymph node metastases were histologically demonstrated, and 6 patients showed a local recurrence. The probability of survival was 1.0 and the probability of being free of local or regional recurrence was between 0.95 and 0.6 depending on the tumor location. CONCLUSIONS: A wait-and-see policy will not necessarily alter the prognosis, which depends on the location of the tumor. Ultrasound follow-up studies should be performed at regular intervals.

Adult↗
PubMed1999

Central electrical stimulation of the auditory pathway in neurofibromatosis type 2.

The auditory brainstem implant (ABI) is a viable treatment option for patients with neurofibromatosis type 2 (NF2) whom either vestibular schwannomas or the surgery used to remove them has rendered totally deaf. This device stimulates the central auditory pathways in a manner similar to the cochlear implant in individuals with a total hearing loss. A multichannel model with transcutaneous signal transmission is in use experimentally in both the United States and Europe. Of 14 patients implanted with the ABI in a European pilot study, 13 received auditory sensations at initial tuning. Surgical implantation of the ABI is generally, but not always, performed at the same time as tumor removal, with the preferred route being the transmastoid-translabyrinthine approach. After insertion, monitoring of the device is required to optimize the location of its electrode on the cochlear nucleus complex.

Electric Stimulation↗
PubMed1998

[Cochlear implants. Prosthetic management of deafness at the turn of the century].

In recent years the cochlear implant has become an established method for rehabilitation of bilateral sensory deafness in adults and children. Intracochlear multichannel stimulation with sophisticated speech coding strategies has proved to be reliable and safe enough for use in adults as well as young children; thus, a few cochlear implant systems with different specifications are currently available. The differences in their hardware and software are discussed. Furthermore, the current indications for cochlear implants in patients whose hearing is severely impaired and important aspects of the preoperative evaluation are presented with special emphasis on difficult cases such as deformities, multihandicapped subjects and very young children. Our results after 12 years of experience and more than 700 implantations suggest that the most important prognostic factor is the duration of deafness.

Adult↗
PubMed1997

[Early and long-term results of rehabilitation of cochlear implant patients]].

BACKGROUND: Cochlear implantation is nowadays a reliable and well-accepted method of auditory rehabilitation in selected adults and children. METHODS: We present rehabilitation data on 21 adult patients provided with the Nucleus CI22 M cochlear implant using the SPEAK strategy. RESULTS: Results of first tune-up show an open set speech understanding in approximately 50% of patients. Long-term results also reveal further improvement in patients who had no open set speech understanding. Our data seem to indicate similar results in comparison to other groups using the CIS strategy. CONCLUSIONS: In adults, open set speech understanding can be achieved even at the first tune-up. Results of early rehabilitation seem to be influenced by duration and etiology of deafness, experience with hearing aids, and other factors.

Adult↗