1,720,985 research outputs found
Il tutore endolaringeo nelle stenosi laringo-tracheali
No full textViene illustrato lL'impiego del tutore endolaringeo nelle stenosi laringo-tracheali
Facilitation of the stapedial reflex by associated tonal stimulation
No full textThe sound stimulus parameters were varied to investigate facilitation effects on the stapedial reflex
Auditory results after vestibular nerve section and intratympanic gentamicin for Ménière's disease.
No full textOBJECTIVE: Hearing loss is a possible complication of vestibular neurectomy and intratympanic gentamicin administration in Ménière's disease. The aim of this study was to compare the incidence of this complication with the two treatments. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: The initial study population reviewed consisted of 24 patients receiving gentamicin injections and 209 patients undergoing vestibular nerve section. Comparison of data was performed among all 24 intratympanic gentamicin patients and the last 24 vestibular neurectomy patients operated on via the retrosigmoid approach. INTERVENTIONS: Intratympanic gentamicin administration (26-156 mg) and retrosigmoid vestibular neurectomy. MAIN OUTCOME MEASURE: Auditory and vertigo results were evaluated according to the American Academy of Otolaryngology 1995 criteria. RESULTS: The mean preoperative pure-tone average for patients undergoing vestibular nerve section was 48.5 dB, with a speech discrimination score of 85%. In these patients, the postoperative pure-tone average was 50.3 dB, and the speech discrimination score was 82%.Patients undergoing gentamicin injection had a mean pretreatment pure-tone average of 50.1 dB and a speech discrimination score of 87%. The posttreatment pure-tone average and discrimination score for the gentamicin group were 74.7 dB and 65%, respectively.The amount of postprocedure hearing loss was significantly greater in the gentamicin group (p = 0.03).Excellent control of vertigo (classes A and B) was obtained in 95.8% of the patients treated with vestibular nerve section and in 75% of the patients in the gentamicin group. CONCLUSION: Gentamicin administration and vestibular neurectomy are both effective for relieving vertigo in Ménière's disease. The incidence of hearing loss is significantly higher after gentamicin injection
Investigations in electrophysiology and morphology of the VIII cranial nerve
No full textThe morphological and functional changes of the eighth nerve in patients undergoing cerebello-pontine angle (CPA) surgery are under investigation in the ENT Department of the University of Verona. The main aspects of the research are: ultrastructural examination of the eighth nerve in normals and subjects operated on for vestibular or cochleo-vestibular neurectomy and for acoustic neuroma; monitoring cochlear nerve function during CPA surgery by monopolar and bipolar recording of cochlear nerve action potential (CNAPs). The specific aims of this research are: to acquire information on the pathophysiology of a number of peripheral cochleo-vestibular disorders; to evaluate the role of intraoperative recording of the eighth nerve in preserving hearing
Mechanisms of auditory impairment during acoustic neuroma surgery
No full textHearing loss during removal of acoustic neuroma (AN) may be due to labyrinthine and/or neural and/or vascular damage. Surgical maneuvers relating to perioperative and postoperative hearing may give rise to mechanisms of auditory impairment. Recording action potentials from the intracranial portion of the cochlear nerve (CN) has proven particularly useful for identifying the mechanisms of iatrogenic auditory injury. In this paper intraoperative and postoperative auditory impairments are investigated in relation to surgical steps in a group of 47 subjects with AN (size ranging from 5 to 25 mm) undergoing removal by a retrosigmoid-transmeatal approach. Drilling of the internal auditory canal (IAC), removal of the AN from the IAC fundus, coagulation close to the CN, lateral to medial tumor traction, separation of the CN from the facial nerve, and stretching of the CN have proven to be the most critical surgical steps in hearing preservation. On the other hand, maneuvers such as intracapsular tumor removal, vestibular neurectomy, suction close to the AN, and closure of the IAC defect did not correlate with changes in auditory potentials. Predisposing factors to postoperative hearing deterioration were IAC enlargement greater than 3 mm, IAC tumor size greater than 7 mm, extracanalar tumor size greater than 20 mm, labyrinth medial to the IAC fundus, severe involvement of the CN in the IAC, preoperative abnormal auditory brainstem responses, and normal vestibular reflectivity. Age and preoperative hearing did not prove to be statistically related to postoperative hearing. The variations in morphology and latency of CNAPs are discussed in relation to the mechanisms of iatrogenic injury
Myelin-containing corpora amylacea in vestibular root entry zone
No full textThe vestibular nerve of patients with Meniere's disease and vascular cross-compression syndrome of the root entry zone due to the antero-inferior cerebellar artery was studied. All patients underwent vestibular neurectomy using the retrosigmoid approach, which permits the removal of a long nerve segment. CA were found in the cytoplasm of astrocytes that had not shown signs of degeneration at the central portion of the vestibular root entry zone. No membrane intervened between CA and the surrounding cytoplasm, which was rich in filaments, in particular near the CA, and poorly equipped with other organelles. CA were round or oval inclusions measuring 10-12 mu-m in diameter. The matrix of the CA was composed of low-density amorphous material, with irregular masses displaying a medium density. A network of randomly oriented filaments and bilaminar, osmiophilic lipid fragments with the same structure and thickness of myelin layers were embedded in the matrix. The CA rich in bilaminar fragments were recognizable also at low magnification for their high electron density. In the astrocytic cytoplasm, near the CA, round or oval shaped, electron-dense bodies with a multilamellar structure were often visible. These results confirm the hypothesis that CA may contain degenerating myelin embedded in a microenvironment rich in glucose polymers and that CA could be an indicator of neurodegeneration
Recent progress in instrumental rhinological diagnosis/ Recenti progressi della diagnostica rinologica strumentale
No full textVengono illustrati i più recenti progressi della diagnostica strumentale nella moderna rinologia
En-block removal of small to medium sized Acoustic Neuromas with Retrosigmoid transmeatal Approach
No full textAbstract
Surgery of acoustic neuroma (AN) has significantly refined over the past years due to a series of advances in diagnostics and surgical technique. Electrophysiologic investigation performed during surgery has greatly contributed to this progress, increasing the surgeon's understanding of the mechanism of damage and suggesting various changes in his or her surgical strategy.In this context, the advantages of the retrosigmoid "en-bloc" removal of small to medium size ANs have been examined in the present study. At the ENT Department of the University of Verona, 103 subjects with AN were operated on, from January 1990 to December 1995, with a retrosigmoid-transmeatal approach. Eighteen subjects (17.4%) presented pure a intracanalar (IC) tumor and 85 (82.6%) had both IC and extracanalar (EC) involvement. All the IC tumors (n = 18) and 70 of the IC-EC neuromas with an EC size less than 25 mm are reported in this paper for a total of 88 patients. The first 48 patients were operated on via the classic procedures described in the literature, characterized by removal of the tumor after "debulking" and limited exposure of the internal auditory canal (IAC). The following 40 subjects were operated on according to the technique of "en-bloc" removal of the tumor and wide exposure of the IAC.In the "en-bloc" group the tumor was first detached from the cerebellar flocculus and the pons, when necessary. The tumor was not debulked to preserve the anatomic relationship with the nerves and to facilitate identification, cleavage and dissection of the tumor from the neural structures. Thereafter, the posterior wall of the IAC was drilled out and opened in a circumferential range from 180 to 270 degrees . The IAC dura was subsequently opened, and the distal end of the AN along with the vestibular nerves were identified. The vestibular nerves were sectioned in the distal portion of the IAC and dissected with the tumor from the underlying facial and cochlear nerves. Dissection continued medially to the IAC porus. The AN was progressively dissected from the cochlear and facial nerves in the cerebellopontine angle (CPA) with multiple direction maneuvers, as required by the characteristics and degree of adherence to the neural structures.The anatomic and functional results obtained with this new procedure ("en-bloc" removal) were compared with the classic "debulking" technique. The statistical analysis shows an improvement in postoperative outcome for both auditory and facial nerve function. The "en-bloc" removal procedure along with the wide exposure of the content of the IAC and electrophysiologic monitoring of the seventh and eighth cranial nerves are, in our experience, the recommended strategies for improving outcomes in small to medium size ANs
Retrosigmoid approach for auditory brainstem implant.
No full textThe present paper reports our experience with the surgical retrosigmoid-transmastoid (RS-TM) technique for implanting auditory brainstem implants (ABIs). From April 1997 to August 1998, four patients with neurofibromatosis type 2 (NF2) were operated on for vestibular schwannoma removal with ABI implantation. The subjects (three men and one women) ranged in age from 22 to 31 years. Tumour size ranged from 12 to 30 mm. A classical RS-TM approach was performed. After tumour excision, identification of landmarks (VIIth, VIIIth and IXth cranial nerves, choroid plexus) to the foramen of Luschka was carefully carried out. The choroid plexus was partially removed and the tela choroidea divided and deflected. The floor of the lateral recess of the fourth ventricle and the convolution of the dorsal cochlear nucleus became visible. The electrode array was then inserted into the lateral recess and placed in the correct position with the help of electrically-evoked auditory brain stem responses. Auditory sensations were induced in all patients with various numbers of electrodes. Different pitch sensations could be identified with different electrode stimulation. Details of the results are presented. In our series, the RS-TM approach represents the elective route for ABI insertion
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