T. Palva

Operative Technique In Mastoid Obliteration

A meatally based postauricular musculoperiosteal flap is recommended for cavity obliteration. With preserved canal wall, it prevents spreadixg of infections to the mastoid cavity. In cases with removed posterior bony wall, a new rigid wall is reconstructed using cortical bone chips and bone dust between fascia and musculo-periosteal flap.

Cochlear Aqueduct in Infants

In six infant ears the cochlear aqueduct had an average length of 3.5 mm while that of adults was earlier found to measure 6.2 mm. The width of the aqueduct was relatively large being at least 150 μm at the narrowest point, 0.5–1 mm from scala tympani. The canal lumen was filled with arachnoid meshwork allowing the passage of erythrocytes into the scala tympani. No barrier membrane appeared at the scala tympani opening and at the meningeal side the dural sheet maintained a tubular canal which opened into the subarachnoid space adjacent to the glossopharyngeal nerve near the jugular bulb. Corpora amylacea were not seen. The arachnoid meshwork thus provides a patient pathway for fluid transport between CSF and perilymph. The relatively large size of the short aqueduct explains why infectious meningeal processes in childhood may reach the inner ear while protection apparently occurs by soft tissue swelling at the meningeal side of the aqueduct.

Disc Electrophoretic Studies of Human Perilymph and Endolymph

Results are reported on micro disc electrophoresis performed on 30 perilymph and 30 utricular endolymph specimens. Contamination with dissolved hemoglobin affects both fluids: four almost pure fluid samples show that the cochlear fluid proteins are made up of strong albumin and two weak prealbumin bands. While LDH isoenzymes 4 and 5 appear more frequently in perilymph than in endolymph, the total concentration of LDH seems to be higher in endolymph than in perilymph, both values being clearly higher than those in serum or CSF.

The Origin of Perilymph Albumin

Results are presented of analyses of serum, CSF, perilymph and endolymph electrophoretic mobilities in 24 cadaver ears. On an average, perilymph and CSF albumin had identical mobility whereas the mobility index of serum albumin was clearly slower than the other two. It is concluded that perilymph albumin, as a rule, has its source in the CSF space and is apparently transported through the cochlear or vestibular aqueduct or along the eighth nerve through foramina at the internal acoustic meatus.

The effect of tonsillectomy and adenoidectomy on the intra-tympanic pressure.

A group of 67 children were studied (mean age 7 years, 2 months) who underwent adenoidectomy and/or tonsillectomy because of either recurrent otitis media or upper respiratory tract infection. The mean pre-operative intratympanic pressure was -67.3 mmH2O (SD 65.1); three months post-operatively it was -21.9 mmH2O (SD 32.4), a highly significant improvement (p less than 0.001). The size of the adenoids had a nearly significant effect on the pre-operative intratympanic pressure (p less than 0.05). In children with large vs small adenoids the difference was highly significant (p less than 0.001). In a group of five children, tonsillectomy alone (adenoidectomy performed earlier) did not have any effect on the intratympanic pressure. No change in intratympanic pressure was seen in children with nasal allergy as compared with non-allergic children after adenoidectomy.

Middle ear epithelium in chronic ear disease.

Thirteen chronically infected temporal bones were serially sectioned and stained to study the characteristics of any possible squamous epithelium. Non-cholesteatomatous epithelium is either immigrative or metaplastic in origin and the choles-teatomatous always immigrative. The metaplastic epithelium does not keratinize and the non-cholesteatomatons immigrative slightly keratinizing type may change into cholesteatomatous aggressive type only in the presence of at present unknown inductors.

Middle Ear Specific Proteins in Glue Ears

Two rabbits were immunized with a pool of mocoid secretion from glue ears. The ear fluids formed up to three specific protein precipitation lines with the absorbed immune serum. One of these proteins was identified as containing acid and another as containing neutral glycoproteins, the third component remained unidentified. The data bring out new evidence of the active secretory capacity of the middle ear mucosa in secretory otitis media.

Auditory Adaptation at Threshold Intensities

Using the technique of manual adaptation test, recordings of perstimulatory changes at threshold were made during a 3-min. stimulation period on 300 patients, suffering mainly of perception deafness. Results are reported of the magnitude of the perstimulatory threshold shift at various frequencies, of the relation of this shift to recruitment phenomenon, and of the frequency of cases with extreme tone decay in various diagnostic groups.

The Chronic Ear: Operative Methods and Results

During the 2-year period of 1964–1965, 303 chronic ears were operated at the Oulu Clinic. In 70 cases a myringoplasty or tympanoplasty was made without mastoid bone work, and in 233 cases the radical bone removal was included. For repair of the drum and part of the meatus, temporal muscle fascia was used exclusively, and the cavity was occluded with the musculoperiosteal pedicle flap as advocated earlier. Certain important phases of the tympanic repair are elaborated, and results in various clinical subgroups presented.

Esterases in post-mortem inner ear fluids.

In electrophoretic analysis, using β-naph-thyl acetate as substrate, post-mortem perilymph and endolymph, CSF and serum all showed 6 esterase fractions while NHS, diluted 1 : 10, had 4 fractions and CSF none. Fractions 1 and 2 were arylesterases while fraction 3 contained α1-arylesteriise, acetylcho-Iinesterase (AChE) and cholinesterase (ChE). Fraction 4 was ChE and fractions 5 and 6 were tissue esterases. ChE was the dominant fraction in serum while AChE dominated in inner ear fluids, brain tissue, acoustic nerve and acoustic turnour homoge-nates.