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Biomedical subjects

T Palva

Publications and source records attributed to T Palva.

227 records · Page 13Linked to original sources
PubMedDate not supplied

Argon laser in otosclerosis surgery.

Data are reported from 323 otosclerotic ears in which primary surgery was carried out by using a large fenestra stapedectomy technique with fascial sealing of the window. In 129 ears the footplate was perforated with an argon laser. In the whole series, one ear became deaf (0.3%) as a result of granulomatous reaction in the operated area. Results in the argon laser group were slightly better than those in the group with mechanical footplate perforation and reconstruction with wire and fascia. Use of argon laser facilitates stapes surgery and, when used judiciously, it is a very helpful tool in all types of ear surgery.

Argon↗
PubMedDate not supplied

Surgical treatment of chronic middle ear disease. II. Canal wall up and canal wall down procedures.

Results of canal wall up (CWU) and canal wall down (CWD) tympanomastoid one-stage surgery were evaluated in 268 ears. In the CWU group of 121 ears, 50 ears (41%) had clinical cholesteatoma, whereas cholesteatoma was present in all 147 ears operated upon by the CWD technique. The disease was much less severe in the former group, which, for instance, showed no labyrith fistula, as compared with 17 (12%) in the latter group. Extensive disease also accounts for the larger number of complications seen in the CWD group. Average hearing levels postoperatively in the CWU group were significantly better than preoperatively. In the CWD group the preoperative levels were maintained. Recurrence of cholesteatoma was noted in 2% in the CWD group, while one implantation cholesteatoma occurred in the CWU group. Of the many surgical procedures available, the one offering the best means of curing the disease should of course be chosen. Ossicular repair with bone offers good prospects of a successful one-stage reconstruction.

Cholesteatoma↗
PubMedDate not supplied

Surgical treatment of chronic middle ear disease. III. Revisions after tympanomastoid surgery.

Revision surgery was performed in 185 ears which had earlier undergone a total of 276 tympanomastoid operations. An open cavity had been made in 98, obliteration in 44 and canal wall up surgery in 43 ears. All ears were now operated upon by the open method combined with ear canal reconstruction and mastoid obliteration. Mastoid cholesteatoma was found in 50% of the open cavities and in 63% of intact canal wall ears, while 80% of the obliterated ears showed mastoid retraction pockets with cholesteatoma. Semicircular canal fistulae occurred in all groups, most frequently in open cavities (11%). During the follow-up period after revision (average 5 years) 3% were reoperated upon because of a new cholesteatoma. In the whole series, average hearing levels were slightly better postoperatively and in 34% of the ears the A-B gap was 20 dB at most. The main reason for failure after primary surgery was inadequate mastoid and epitympanic bone work and failure to obliterate the medial parts of the cavity thoroughly.

Cholesteatoma↗
PubMedDate not supplied

Audiological results using single-channel intracochlear implant, vibrotactile aid or acoustic hearing aids.

Users of a single-channel intracochlear implant (CI, n = 10) (3M/House), a single-channel vibrotactile aid (V, n = 8) (Minivib 3/Special Instrument Ab) and acoustic hearing aids (HA, n = 9) were tested. The comparison was made after training and a minimum of 11 months' use of the devices. All subjects were considered profoundly deaf, but the HA group had some residual hearing. The HA group achieved the best mean test scores in all the tests given. The difference between the CI group and V group increased, in favour to the CI users, as the auditory task was changed from the level of simple signal analysis to the level of linguistic interpretation.

Adult↗
PubMedDate not supplied

Inflammatory cells in chronic middle ear disease. Value of lymphocyte subset determination in ear surgery.

Lymphoid cell subsets were studied in biopsy specimens of uninfected and infected ear canal epidermis, tympanic membrane, cholesteatoma epithelium, and middle ear and antrum granulation tissue. All specimens showing uninfected squamous epithelium, including those of cholesteatoma membrane, contained only a few lymphoid cells. Biopsies of infected squamous epithelium showed enhanced Ts/c activity in the subepithelial layer. Granulation tissue showed normal Th/i activity. B-cells and NK cells appeared in small numbers. Lymphoid cell subset analysis is indicated in ears reconstructed with allograft material to detect signs of rejection. It is of little value in cases of chronic inflammatory middle ear disease which have not previously been operated upon.

Cholesteatoma↗
PubMedDate not supplied

Revision surgery for otosclerosis.

The outcome of surgery was analyzed in 76 otosclerosis patients (82 operations) undergoing revisions during the period 1986-89. The ears were divided into 3 groups based on preoperative A-B gaps 1) larger than 25 dB, 2) between 10 to 25 dB, and 3) less than 10 dB. A final hearing gain of more than 11 dB was recorded in 76%, 40% and 10% of the ears in groups 1, 2 and 3, respectively. In the groups with conductive component none of the ears deteriorated. In the sensorineural group 2 patients suffered further loss of 10 and 29 dB, respectively, and one ear became deaf. At revision the most common causes of conductive impairment were found to be dislocation of the prosthesis, remnants of footplate or new bone growth. Fistula was suspected in 10 ears and verified in 5. Several reconstruction methods must be mastered.

Cochlear Implants↗
PubMedDate not supplied

Surgical anatomy of the internal auditory canal. A temporal bone dissection study.

The suboccipital fossa approach to the fundus of the internal auditory canal (IAC) at acoustic neurinoma surgery was investigated in 32 temporal bones. A microdissection was done under the operating microscope in a specially constructed holder so that the surgeon's exposure and angles of view through the craniotomy were mimicked. It was possible to obtain an unobstructed view of the transverse crest and the vestibular nerves in all specimens without the bony labyrinth being opened in the process. A prerequisite was that, as the posterior wall of the IAC was removed, drilling did not extend lateral to a line running through the midpoint of the craniotomy to the transverse crest. The distances of major structures from the posterior and superior pyramid surface were measured, using a special impression technique that made it possible to measure the thickness of the bony layer removed.

Adolescent↗
PubMedDate not supplied

The pathogenesis and treatment of cholesteatoma.

Congenital cholesteatoma, which arises from embryonic epidermoid tissue, is rare. In the majority of cases the cholesteatoma is acquired. It may develop as a retraction pocket involving the whole membrane, as a result of migration over the perforation edges or as basal cell invasion behind an intact membrane. There is no evidence for a metaplastic process or a Langerhans' cell mediated origin. Treatment modalities include several methods of either conservative or radical surgery, the main aim being one-stage total eradication of cholesteatoma and simultaneous reconstruction. With appropriate surgical methods recurrence figures after 5 years should remain under 10%. The patient's own tissues are the material of choice in the reconstruction.

Cholesteatoma↗
PubMedDate not supplied

Langerhans' cells in chronic otitis media.

Langerhans cells (LCs) were studied in chronic otitis media (COM) by the immunoperoxidase technique and monoclonal antibodies. The LCs were a regular finding in both thin and thick cholesteatoma epithelium, and in open cavity skin. OKT-6 positive cells were also found in smaller numbers in subepithelial connective tissue and lymphoid follicles, and in cuboidal secretory epithelium. LCs form an important part of the immune defence system of the skin, which lacks the humoral secretory IgA defence mechanism of the mucous membranes. There is no proof that LCs are connected with the keratinization process and possible reformation of cholesteatoma.

Antigens, Surface↗
PubMedDate not supplied

Comparison of pure tones and noise stimuli in sonotubometry.

Sonometric data on the Eustachian tube opening response to swallowing and to pressing the mandible down were evaluated in 51 normal ears and 62 ears with chronic disease. Testing with a narrow-band noise which was centered on 7 and 8 kHz gave the best results. The limit for a positive response was set at 3 dB, and of the normal ears, 80% showed a positive response in a short routine test. The data correlated reasonably well with surgical results. If test results point to tubal insufficiency, measures should be taken to prevent the formation of retraction pockets.

Acoustic Stimulation↗