[Medial acoustic neurinomas. A new clinical subsection of acoustic neurinomas].
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Ear, Inner↗
Biomedical subjects
M Tos
Publications and source records attributed to M Tos.
[Mechanical suturing devices in bronchopulmonary surgery].
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Bronchi↗
Medial acoustic neuromas. A new clinical entity.
The medial acoustic neuroma, a new clinical entity, is defined as an extrameatal tumor without tumor mass laterally in the internal acoustic meatus. During a 12-year period in Denmark, in a prospective analysis of 400 acoustic neuromas on which surgery was performed by the translabyrinthine approach, 48 tumors (12%) were medial tumors, corresponding to an incidence of 0.8 tumors per million inhabitants per year. Analysis of the symptoms and results showed that medial tumors are generally larger with more severe involvement of the cerebellum, the trigeminal nerve, and the brain stem, compared with the 352 nonmedial tumors. Because of its onset in the medial part of the vestibular nerve, the tumor may grow silently and to a considerable size without any widening of the internal auditory canal and with relatively good hearing. Meaningful hearing preservation is impossible in medial tumors, because the smallest medial tumor (subject's hearing, 40 dB or better) measured 3 cm, and the majority of tumors are giant tumors.
Adult↗
Allograft stapes-incus assembly. Long-term results.
In 35 patients with absence of the stapedial arch, with a history of radical surgery, and without ossicles, the head of an allograft stapes was placed on the patients' footplates and an allograft incus body on the top of this. The long-term results of this assembly, judging by different methods of analysis, are still somewhat better than those of 98 ears with approximately the same pathologic condition treated by an allograft incus as the columella between the footplate and fascia. The allograft stapes-incus assembly is an alternative method to the commonly used incudal columella. The allograft stapes has not been resorbed to a significant degree during the years after surgery.
Ear Ossicles↗
Some aspects of life quality after surgery for acoustic neuroma.
This investigation was performed to describe some aspects of the quality of life in subjects after translabyrinthine removal of an acoustic neuroma, resulting in unilateral total deafness. Two hundred ninety-three subjects who had been operated on during 1976 through 1990 and who were living outside the Copenhagen (Denmark) City and County received a postal questionnaire, to which 93% (n = 273) responded: 118 men and 155 women with a median age of 58 years (range, 18 to 81 years). The median observation period from surgery to the questionnaire was 6 years (range, 6 months to 14 years), and the median age at operation was 52 years (range, 15 to 76 years). Among the subjects, 22% had received postoperative hearing rehabilitation with various types of hearing aids in the ear not operated on. In 62%, tinnitus was experienced in the ear with tumor before surgery, and at the time of the questionnaire, 49% experienced tinnitus in the ear operated on. Half a year after surgery, 56% still experienced dizziness. Sixty-four percent reported damage to the facial nerve in relationship to the operation. At the time of the questionnaire, 12% indicated a total loss of facial nerve function. No vocational consequences were found in 74% after surgery. Information concerning different symptoms related to surgery was insufficient in 29%, while the quality of information in relation to surgery was more satisfying. In conclusion, the study demonstrates that deafness, dysequilibrium, and reduced facial nerve function caused the most severe problems. Improved information to patients before surgery may reduce the frequency of negative experiences.
Adolescent↗
Correlation between temporal bone pneumatization, location of lateral sinus and length of the mastoid process.
The relationship between temporal bone pneumatization and the location of the lateral sinus and length of the mastoid process was investigated in 60 fresh frozen adult temporal bones, by plain X-rays, computed tomography and surgical dissection including otomicroscopic findings. Temporal bone pneumatization was classified as small, moderate and large. After drilling, the shortest distances between the middle fossa dura and mastoid tip representing the mastoid length and between the sigmoid sinus and posterior border of external auditory canal were measured and compared to the degree of pneumatization. The distances in the specimens with pathological eardrum and adhesions in the middle ear were compared to the ones without gross pathology. The length of mastoid process was significantly shorter in specimens with small pneumatization than those with large (Mann Whitney P less than 0.001). The specimens with a pathological eardrum and middle ear adhesions had a significantly shorter mastoid length than those without gross pathology. There was no significant difference between degree of pneumatization and the shortest distance between sigmoid sinus and external auditory canal (Mann Whitney P greater than 0.05). It is demonstrated that the 'under-developed' mastoid process can be a consequence of hampered pneumatization.
Adult↗
Ear polyps in posterior superior retraction pockets, herodion. Histopathological and pathogenetic aspects.
Histopathological characteristics of 20 ear herodion polyps with a certain localisation and a well-known underlying pathological process were studied in order to elucidate the pathogenesis of ear mucosal polyp formation. Only 12 of the polyps were covered with epithelium; either a squamous keratinized epithelium or a cylindrical epithelium. Three polyps were covered with cylindrical and squamous keratinized epithelium. Incipient gland formation was seen and glands were only found in 35% of the polyps. It seems possible that the polyp is a local newly formed process and may have the aim of catching, eliminating and digesting bacteria and dead cells.
Adolescent↗
Causes of facial nerve paresis after translabyrinthine surgery for acoustic neuroma.
Forty-six consecutive video-recorded translabyrinthine operations at Gentofte Hospital, for tumors of 5 to 25 mm, were investigated for possible damage to the facial nerve from cauterization, suction, stretching, pushing, and other instrumental trauma at the following regions: fundus, internal meatus, porus, cerebellopontine angle, and brain stem. House-Brackmann grading of the postoperative facial nerve function was determined from the patient records for the 1st, 3rd, and 10th days and 3 months and 6 months postoperatively, as well as the final status. Suction on the nerve seems to be the most important factor for perioperative facial nerve damage. The most common site of damage was the porus region. This investigation shows thermic drilling lesions to be very relevant. There was no correlation between the degree and character of damage and the postoperative facial nerve function. In eight patients we cannot explain the postoperative facial palsy.
Facial Nerve↗
The early stages of polyp formation.
The purpose of this study is to describe polyp formation in the mucosa of the middle ear as a possible model for the pathogenesis of nasal polyps. In 65 Wistar rats, the eustachian tube was occluded on the left side for up to 20 months; 60 right-sided, nonoccluded ears served as controls. Following occlusion, the middle ear mucosa was examined for signs of polyps. Signs of polyp formation or fully developed polyps were seen in 14 (22%) of the middle ears, and were only seen in middle ears with signs of actual or previous infection. It was established that the first stages of polyp formation include epithelial rupture, proliferation of fibrous tissue through the epithelial defect, and epithelialization of the prolapsed fibrous tissue by proliferation and migration of epithelial cells from the surrounding epithelium until there is full epithelial covering of the polyp. This report discusses whether the described middle ear model may form basis for the explanation of the pathogenesis of nasal polyps.
Animals↗
Incidence and progression of myringo-incudo-pexy after secretory otitis.
A cohort of originally 327 healthy children born in 1975 was followed by repeated otomicroscopies and tympanometries from age 5 to age 16 years, in total 9 otomicroscopies. Prevalence of drum pathology, especially myringo-incudo-pexy was investigated. Prevalence of myringo-incudo-pexy was 0.5% at age 5 years, 2.5% at age 7 and 4.2% at age 16. Forty percent of pexies were stable; 36% fluctuated and 26% disappeared. Hearing was surprisingly good at age 16, but the pexy represents a risk for progression.
Acoustic Impedance Tests↗
Suboccipital acoustic neuroma surgery: results of decentralized neurosurgical tumor removal in Denmark.
From 1979 to 1990, a series of 59 patients with 59 acoustic neuromas were operated on in five departments of neurosurgery by at least five different neurosurgical teams, employing the suboccipital approach. Perioperative mortality rate was 8.5%. Complications including hematoma, ventricular hemorrhage, meningitis, hemiparalysis, abducens nerve paralysis, recurrent nerve paralysis, postoperative wound infection and CSF leak were observed in 21 patients (35.6%). Total tumor removal was not possible in 17 patients (28.8%). Converting the postoperative facial nerve function to House-Brackmann (HB) classification, 34 patients (57.6%) were regarded as HB 6. Reconstruction of the facial nerve was attempted in 19 patients (32.2%). Attempts at hearing preservation were unsuccessful in all patients. Failure to attain better results and the importance of centralized treatment of acoustic neuroma are emphasized.
Adult↗
Daily impedance audiometric screening of children. Validity of impedance tympanoscope ZS331 compared with impedance audiometer AZ7.
The purpose of the present study was to test a fully automated screening impedance tympanoscope against a clinical impedance audiometer. Previous studies have indicated a relatively high incidence of type B tympanograms when using the tympanoscope and in addition shown a surprisingly large number of type B curves of one day's duration. The present study was based on 51 otherwise healthy children attending kindergartens (100 ears) who underwent daily tympanometric screening with both the impedance tympanoscope ZS331 and the impedance audiometer AZ7. The tympanoscope indicated a significantly larger number of type B tympanograms, and in 16 cases the type B curves could be demonstrated on only one day, resulting in significantly higher point and period prevalences of type B tympanograms. The difference is mainly attributable to the different ways in which a type B tympanogram is defined by the two instruments. On the basis of the present study we conclude that the impedance tympanoscope is not well suited for this type of study.
Acoustic Impedance Tests↗
Fireside conference 2. Pathogenesis of nasal polyps.
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Animals↗
Incidence of acoustic neuromas.
The annual incidence of diagnosed acoustic neuromas in Denmark during two 7-year periods from June 1976 to June 1990 was compared, collecting all operated and non-operated tumors from the entire country. During the first period 278 tumors were diagnosed with an annual incidence of 38 tumors or 7.8 tumors per million per year. During the second period the annual incidence rose to 48 tumors and 9.4 tumors per million per year. There was a significant decrease of extrameatal tumor size from 33 to 26 mm and diminishing of giant tumors.
Denmark↗
[False-positive diagnostic findings in acoustic neurinomas].
In the period from 1976 to 1990 Tos and Thomsen operated on 520 patients with acoustic neuromas using the translabyrinthine approach and five other patients were operated on via middle fossa approach. The diagnostic work up in all patients included: pure tone audiometry, tympanogram with acoustic reflexes, caloric test and brainstem audiometry. Since the late seventies, CT became the radiological investigation of choice to visualize the tumor. The first generation of CT failed to reveal tumors less than 1.5 cm in the extrameatal diameter, and pantopaque cisternography was necessary in some cases. The following generation of CT did not always reveal small intrameatal tumors, and false-negative results were reported. The incidence of false-positive CT findings in our series is calculated to be 0.6%. Three patients were operated on on account of false-positive CT. Peroperatively, adhesions in and around the internal porus were found in two cases while no pathology was found in the third case. Postoperatively, anacusis was observed in two cases. This could have been avoided if magnetic resonance imaging (MRI) with gadolinium contrast had been performed. In our opinion, MRI should be considered before a definitive surgical procedure is undertaken. Until MRI becomes more widely available, intravenous contrast-enhanced tomography followed by air cisternography is recommended in the diagnosis of small acoustic neuromas.
Adult↗
[Functional endoscopic endonasal sinus surgery].
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Adult↗
Origin of nasal polyps.
The nasoethmoid complexes from 6 patients with nasal polyps were systematically examined. First, the location and place of the origin of the polyps were recorded and photographed. The polyps and their places of origin were removed, serial sectioned, and examined. In all 6 patients, the polyps originated from the nasal mucosa. Most of the polyps extended laterally from the mucosa into the anterior part of the middle meatus. Several polyps originated from the mucosa near the ethmoid cell ostium or directly from the mucosa lining the edge of the ostium. The ostia themselves were not blocked by the polyps, and there was no indication of polyp formation in the ethmoid cells.
Aged↗
Inverted papilloma of the nasal cavity: pathological aspects in a follow-up study.
The initially removed tumors from 42 patients with inverted papillomas of the nasal cavity and paranasal sinuses were subjected to an extensive histopathological examination in order to define the characteristics associated with multiple recurrences and development of malignancy. Two of the patients subsequently developed squamous cell carcinoma and eight patients had more than one recurrence. No specific histological characteristic was determined to be a predictor of multiple recurrences or development of malignancy. However, three patterns of characteristics emerged from the data which were found to be related to the development of malignancy, multiple recurrences, and benign behaviour. Malignancy was found to be associated with bilateral inverted papilloma, a predominance of mature squamous epithelium, the presence of all three epithelial types (metaplastic squamous, mature squamous, and cylindrical), severe hyperkeratosis, a mitotic index greater than or equal to 2 per high-power field (HPF), absence of inflammatory polyps among the papillomas, an abundance of plasma cells, and an absence of neutrophils. Multiple recurrences (without malignancy) were associated with a mitotic index greater than or equal to 2 per HPF and an absence of inflammatory polyps. Benign behaviour was associated with predominantly mucinous tumors, a mitotic index less than 1 per HPF, a ratio of neoplastic epithelium/connective tissue stroma greater than or equal to 6, and the presence of inflammatory polyps among the papillomas.
Carcinoma, Squamous Cell↗