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Biomedical subjects

T Palva

Publications and source records attributed to T Palva.

At least 91 records · Page 5Linked to original sources
PubMed1980

The cochlear nerve in Meniere's disease.

Cochlear nerves of 11 patients with advanced Meniere's disease were studied by light and electron microscopy. All the nerves appeared normal on light microscopy. In cross sections, the density of myelinated nerve fibers was approximately 20,000 fibers per square millimeter in most cases. In two cases, the density was reduced, about 14,000/sq mm. No correlation was found between the age of patients or the duration of the disease and the density of myelinated nerve fibers. On electron microscopy, there were several features that suggested primary axonal degeneration or segmental demyelination in the cochlear nerve.

Age Factors↗
PubMed1980

Vestibular nerve in Meniere's disease.

Biopsy specimens of vestibular nerves of 40 patients with severe Meniere's disease were studied by microscopy. In 17 patients, a translabyrinthine eighth nerve transection was done; in 23 patients, a middle fossa vestibular neurectomy was done. Many of the nerve fibers had thickened and deformed myelin coats; some were thinly myelinated fibers and some showed degraded myelin. No macrophages were present. Occasional vestibular ganglion cells had thin myelin coats. In six patients, there were lighter areas between the fibers. In these there were roughly parallel astrocyte processes, with numerous cytoplasmic filaments. The light areas were surrounded by a basement membrane. Four of these patients showed continuation of vertiginous symptoms after operation and were not helped by surgery. These patients may suffer from a neuropathy that is different from the more common causes of Meniere's disease.

Adult↗
PubMed1980

Vestibular findings in patients with acoustic neurinoma.

We studied the vestibular system of 30 patients with eighth nerve schwannoma. Preoperatively, cold and warm calorizations were performed. At operation, the utriculus and the ampulla of the horizontal semicircular canal as well as the eighth nerve were identified and removed for study. The sensory epithelium of utricular macula and ampullar crista appeared fairly normal in most cases. In one, there was tumor invasion to the labyrinth and in another patchy necrosis of the sensory epithelium. The number and quality of sensory cells varied from case to case. In cases with intact superior vestibular nerve, on light microscopy the histopathologic features of sensory epithelia did not differentiate between groups and symmetrical caloric reactions and with reduced or absent caloric reactions.

Adult↗
PubMed1979

The meatally based musculoperiosteal flap in cavity obliteration.

A meatally based musculoperiosteal flap that was formed for radical mastoid cavity obliteration was deliberately excised during revision surgery in three cases of recurring tympanic cholesteatoma. The flaps, which contained subcutaneous connective tissue, were well vascularized and contained large, viable muscle bundles and many nerve trunks from the postauricular branch of the facial nerve. In two cases, the periosteum-attached bone chips that had been removed from the patient's mastoid tip region and implanted to form a new bony canal wall were viable and gave the intended support for the meatus after radical ear surgery.

Adolescent↗
PubMed1979

Vestibular sensory epithelium in Meniere's disease.

Utricle and horizontal semicircular canal ampulla removed during labyrinthectomy from 11 patients with advanced Meniere's disease were studied under light and electron microscope. In light microscopy the epithelium of both sensory areas appeared fairly normal. Many sensory cells revealed fluid-filled crescents at the nucleus and many cells were extensively vacuolated. Ultrastructurally, a part of the observations were apparently artifacts due to specimen handling; some were normal, age-related findings. Some changes were considered secondary to dilation of the endolymphatic space. True signs of degeneration, seldom seen in these specimens were intraepithelial cysts, necrotic cells, and dark homogeneous masses in the sensory epithelium and dilated nerve fibers in the subepithelial tissue. No general degeneration of the utricular macula or ampullar crista seems to occur in Meniere's disease.

Adult↗
PubMed1979

Adrenergic innervation of blood vessels. A fluorescence microscopic study of the eighth nerve and inner ear structures in man.

Fluorescence microscopy was used to examine the perivascular adrenergic innervation in the eighth nerve and vestibular end-organ specimens from 13 patients with otoneurological diseases. It was observed that all the blood vessels accompanying the cochlear and vestibular nerves from patients with acoustic neuroma or Meniere's disease were devoid of specifically fluorescent fibers, while several adrenergic fibers were seen around the arterioles accompanying the inferior vestibular nerve from the patient with sudden deafness.

Adrenergic Fibers↗
PubMed1979

Adrenergic innervation of the eighth nerve and vestibular end organs in man.

Fluorescence microscopy was used to examine the adrenergic, blood-vessel-independent innervation of the 8th nerve and inner ear specimens in patients with otoneurological diseases. Specifically fluorescent adrenergic axons were scantily seen among the myelinated nerve fibers in the 8th nerve and in the subepithelial regions of the end organs but not in the endolymphatic sac.

Adrenergic Fibers↗
PubMed1979

Menière's disease: morphological findings in eighth nerve and vestibular end organs.

37 patients with advanced Menière's disease were operated on by translabyrinthine 8th nerve neurectomy or middle fossa vestibular neurectomy. Cochlear and vestibular nerves, epithelia of the utricular macula and ampullar crista of horizontal canal were studied. All specimens were fairly well preserved and the microscopic studies suggested that there is no general deterioration of these structures even in long-standing, advanced Menière's disease, but some minor deviations from normal are present in individual cells.

Adult↗
PubMed1979

Functional and histological findings in acoustic neuroma.

27 patients with acoustic neuroma were operated on by translabyrinthine tumor removal. At operation 8th nerve compartments were identified and removed for study. Results of the audiological test battery and vestibular tests were compared with histological state of the nerve specimens studied. The tumor appears only seldom to invade the cochlear nerve in cases with 'cochlear' hearing loss, but in the majority of cases with 'retrocochlear' hearing loss the cochlear nerve is invaded.

Cochlear Nerve↗
PubMed1979

Recent expericience in the surgery of acoustic neurinomas.

A translabyrinthine method was used in 49 and a suboccipital approach in 55 cases, for the removal of an acoustic neuroma. The translabyrinthine procedure is well suited in cases with no pontine compression, whereas in large tumours the wide opening in the suboccipital method gives added safety to the procedure. The mortality rate was 3% and the facial nerve function after translabyrinthie surgery showed permanent paralysis in 4 patients. A team approach using the suboccipital route has been started in an attempt to save hearing in small- and medium-sized tumours.

Ear, Inner↗
PubMed1979

Vestibular neurectomy.

Vestibular neurectomy technique used for the standard middle fossa approach and for a total translabyrithine VIII nerve section is described. The middle fossa approach has been used in 49 cases of mainly Meniere's disease and basically the same approach for nerve decompression has been used in 19 cases of facial paralysis, 15 being due to Bell's palsy, 2 to petrous pyramid cholesteatoma and 2 to facial nerve Schwannoma. In unilateral Meniere's disease with no further function in hearing, vestibular neurectomy gives good results in alleviating vertigo.

Cholesteatoma↗
PubMed1979

Mastoid obliteration.

Mastoid obliteration is recommended as a routine procedure in all mastoid surgery. Bone chips from the mastoid tip, bone paté from the cortical bone and lyophilized dura can all be employed effectively to fill the epitympanic space and Traumann's triangle. The former annulus is reconstructed using lyodura and periost-bearing bone and the canal wall is fortified and the cavity filled with the metally based postauricular musculoperiosteal flap. Any remaining cavity is filled with bone chips and bone paté.

Bone Transplantation↗
PubMed1979

Vestibular neurectomy and saccus decompression surgery in Meniere's disease.

Results of vestibular neurectomy, total eighth nerve section, and saccus decompression in 42 patients with Meniere's disease are reported. Vestibular nerve section was found in isolated cases to be a very effective method of abolishing the symptom of vertigo. Hearing is not affected but may be lost owing to opening of the vertical canal or disruption of blood supply. Saccus surgery might be the surgical treatment of choice in early cases with good hearing but in patients with fixed non-fluctuating hearing loss, rehabilitation can be effected only by vestibular neurectomy. In bilateral cases either sac surgery or the use of vestibulotoxic drugs is advised.

Adult↗
PubMed1978

Ultrastructural features of spiral ganglion cells. A study of patients with hearing loss of varying origins.

Fresh specimens of the acoustic nerve that were obtained during vestibular neurectomy or acoustic neuroma removal were studied for structure of the spiral ganglion cells. These were large, round or oval cells with many cytoplasmic organelles and were surrounded by Schwann cells. Schwann cells formed a single layer or perikaryal sheath and the cells were thus unmyelinated. In one case the specimen contained part of the spiral ganglion, but in six others spiral ganglion cells were found outside of Rosenthal's canal, among the myelinated nerve fibers. In three cases the ear was deaf due to cochlear insult, but the nerve fibers and ganglion cells showed no retrograde degeneration. The neurophysiologic features of the cochlear nerve should be considered because unmyelinated ganglion cells may have a different conduction capacity in comparison with thickly myelinated cells.

Adult↗
PubMed1978

Pathologic features of the cochlear nerve in profound deafness.

Cochlear nerves transected in the internal meatus were studied in six totally deaf ears and in one ear with profound deafness. In five ears deafness had followed surgical procedures in the oval window, in one it was the result of a mumps infection, and one was probably due to a virus infection or a vascular lesion. In four cases there was no great reduction in the nerve fiber population and the ultrastructure appeared normal. In three nerves there was a reduction in the number of nerve fibers, interfibrillar fibrosis, and disorganized material or extensive degenerative changes in the myelin sheaths. In all specimens artificial myelin changes were seen that apparently resulted from manipulation of the specimens at removal. Analysis of these cochlear nerves suggests that retrograde degeneration after severe cochlear insults may not be as frequent as has been thought on the basis of animal studies.

Adult↗
PubMed1978

Eighth nerve in acoustic neuromas. Special reference to superior vestibular nerve function and histopathology.

Eighth nerve specimens were removed during acoustic neuroma surgery, and findings were related to cochlear and especially to superior vestibular nerve function as studied by conventional caloric testing in 21 cases. The origin of the tumor was in eight cases the inferior and in two cases the superior vestibular nerve, and in eight cases the vestibular nerve without more specific localization. In three advanced cases the exact site of origin could not be determined. Leaving age-related changes out of account, the utricle and horizontal canal ampulla appeared normal in all ears except one in which the ampulla was replaced by tumor tissue. In 11 ears the superior vestibular nerve was histologically intact and three of these ears also showed normal caloric responses. In seven ears there was a canal paresis, and in three no reaction was obtained. The ten ears with partial or total nerve invasion by tumor either showed a weak reaction or no response at all. It is likely that an early conduction block arises in both cochlear and vestibular nerves, and reduced reactions to appropriate stimuli do not warrant conclusions that the numbers of anatomically intact nerve fibers possibly are reduced.

Adult↗
PubMed1978

Cochlear nerve in neurilemomas. Audiology and histopathology.

Correlative data between the histopathologic changes in the cochlear nerve and audiologic findings are reported in 16 cases of neurilemomas. Poor speech discrimination, positive or absent recruitment, excessive adaptation, or separation of forward vs reverse continuous tone Bekesy tracings did not correlate with the number of preserved nerve fibers. There were several cases with profound hearing loss in which the nerve fiber population approached normal. Histologically, pathologic changes included dilated fibers and increased interfibrillary collagen. In many specimens the fibers were further apart than normally, especially in the immediate vicinity of the tumor, and many lay between tumor cells. The tumor-nerve interface was usually gradual and no abrupt change appeared at the transition from the nerve to the tumor, the Schwann cells appearing to continue as tumor cells. Nonspecific changes apparently due to specimen handling were seen in some areas of most specimens.

Adult↗