Biomedical subjects

K Paulsen

Publications and source records attributed to K Paulsen.

At least 37 records · Page 2Linked to original sources

PubMed1975

[Measurement of sound transmitted through the body while drilling and grinding isolated petrous temporal bone (author's transl)].

Measurements of the effect of rotating drills and grinders on isolated fresh temporal bone on the sound transmitted through the body have not previously been made known. In contrast to measurement of air-conducted sound, they include the portion of sound which effects the hearing apparatus of the patient through the bone during the process of drilling the temporal bobe. Measurements were made with a calibrated acceleration pick-up in conjunction with a precision sound level meter (test amplifier with sound frequency analyser). The recording was made continuously between 20 Hz and 20 000 Hz. The range between 250 Hz and 8000 Hz was examined mathematically. Above 8000 Hz the curves dropped markedly, apart from a few exceptions. The level of the sound depends largely on the size of the drill bit, and consequently on the breadth and depth of the rotating cutting edges. The smaller drill heads produce a considerably smaller quantity of sound. The highest level of sound comes from the burrs and wing-cutters. The diamond head lies lower in the scale, but almost equals the effect of the steel drills. The speed of rotation of the drill head plays only a subordinate role. Between 16 000 and 80 000 r.p.m. the values are the same. In the region of 10 000 r.p.m. the sound level is frequently reduced, even if a few loud peaks may still occur here. The type of drilling machine, the handpiece or transmission handpiece used have no effect. Altogether, the rotary drill produces less sound transmitted to the inner ear through the body than through the air.

Bone Conduction↗

PubMed1975

[Facial paresis following stapedectomy (author's transl)].

An ususual complication after stapedectomy for otosclerosis is reported. After two vain attempts elsewhere, the tympanic cavity was opened for the third time. Since the incus was missing, a malleovestibuloplasty was undertaken, using the Schuknecht wire prosthesis. Hearing was very good. One day after the operation, a facial paralysis developed, and increased over the following days. After 18 days, the nerve was found to be oedematous and swollen above the fenestra ovale upto the level of the promontory and had forced the prosthesis out of the fenestra ovale. Six weeks later, nerve function was normal.

Facial Paralysis↗

PubMed1975

[Microcoagulation in the treatment of facial spasm (author's transl)].

A method for the surgical treatment of facial spasm is described. The nerve trunk is exposed in the mastoid region and the sheath is opened. With a bipolar electrode, microspots are burnt spirally round the nerve trunk and also at a few places in the centre of the nerve after pulling the bundles apart. Three cases are reported and assessed in comparison with the methods of Miehlke, Fisch, Rosemann and Schaupp. The more rapid and easier delineation of the nerve trunk in the event of a recurrence are considered an advantage compared with the extratemporal methods.

Electrocoagulation↗

PubMed1975

[Noise level measurements of the air noise during drilling and grinding on the fresh isolated temporal bone (author's transl)].

Aerial sound measurements with different drilling instruments were performed during dry running and preparations of the bone. Registered were the values of the small drilling instruments Sirona, Dentatus-Air, and Electro-Torque-Ritter. Also tested were the KaVo-Technique-machine, the Hall-machine, the Air-Orbit-turbine, and the Sirona-turbine. During dry running most of them already reached the allowed marginal value of noise nuisance for the ear of 85 dB (A) at a distance of 35 cm. Only the Air-Orbit-machine showed a slightly lower value of 80 dB (A). The level increases with the used handpieces. Normal handpieces 1:1 exert only a minimal influence, gear handpieces 2:1, however, markedly increase the level. The verticity is of no importance in the range of normal rotations between 10,000 r/min. and 80,000 r/min. Only rotations in the lower frequency range of 2,000 r/min. markedly decrease the noise level. During bone drilling, the kind and size of the drilling bit have an influence on the intensity of the noise level. Quadruple wing milling cutters create a very high noise level (at a distance of 15 cm still above 110 dB [A!]), big rose cutters (R 16) create noise levels of 95 dB (A) and above, and only diamond round bits create less noise (approximately 88 db [A]). Small drilling bits make such a faint noise, that it is overroared by the drilling instrument. The turbines create only slightly higher levels than during dry running. Larger drilling bits cannot be employed here on principle. Wing milling cutters can lead to persistent damages of the inner ear. The frequent use of dental drilling instruments for bone preparations can also lead to a hearing loss of the operator in the long run.

Humans↗

PubMed1975

[Investigations on the shape and size of bone-chips produced during boring and grinding (author's transl)].

Examinations of the shape and size of chips produced during boring and grinding of dry macerated and fresh temporal bone by various drills and grinders at different revolutions show that rose trepans mainly scrape fresh bone, producing large rolled-up chips, but knock off dry macerated bone, producing more compact chips of bizarre shape. In either case the chip waste also contains plenty of fine and finest compact chips which are broken off and splinter during the removal or knocking-off of the chips from solid bone. The size of the chip depends on the size of the drill head. Diamond cutting heads produce fine and finest compact bone chips. Bone milling produces plenty of scrapes even from dry macerated temporal bone. The rate of revolutions (10,000-80,000 per min) had no influence on the shape and size of chips. Clinically the scraped chip seems to be the most favourable in the drilling of bone because it causes least damage. The use of a drill head with sharp-edged, intact cutting surfaces seems important for this, with continuous rinsing during the boring process to prevent soiling of the interspaces between the cutters and to ensure full performance in accordance with their construction.

Humans↗

PubMed1974