Battery-powered miniature implant for electrical nerve stimulation.

The range of application of implantable stimulators in functional electrical stimulation (FES) for therapeutic purposes and for the restoration of lost or damaged functions has steadily grown within the last 20 years. Each time a clinically used method is improved, a new field of FES application explored or basic research conducted, animal experiments are needed to check and evaluate the findings and results. It is precisely for this use that the stimulation system described in this paper was developed.

Flexible fiberoptic endoscopy and laser surgery in obliterated cochleas: human temporal bone studies.

Background And Objective: The use of conventional drilling procedures in cochlear implant surgery of ossified cochleae poses special risks to the facial nerve and the carotid artery. This study evaluated the alternate use of flexible fiberoptic endoscopy and mid-infrared laser surgery for recanalization of partially and artificially obliterated cochleae in freshly dissected human cadavers.

Study Design/materials And Methods: A pulsed Holmium:YAG-laser (lambda = 2120 nm) was used in the free-running mode (1180 mJ, 250 microseconds pulse, 5 Hz).

Long-term results after stapedectomy versus stapedotomy.

In a retrospective study postoperative hearing results after stapedotomy were compared with those after stapedectomy. Of 117 patients suffering from otosclerosis, 93 percent were primarily successfully operated between 1980 and 1990 in the ENT department of the University of Vienna. Long-term results from 35 stapedotomies and 22 stapedectomies were compared.

[Experimental laser surgery of the ossified cochlea].

A pulsed holmium: YAG-laser (lambda = 2120 nm) was used to reopen the basal turn of artificially obliterated human cochleas in freshly dissected cadavers for intracochlear insertion of the stimulation electrode of a cochlear implant under simulated surgical conditions. Laser energy was transmitted through a 400 microns nylon fibre via the opened facial recess directly to the round window niche. At an energy level of 500 mJ/2.

The Vienna Cochlear Implant in patients with obliteration of the cochlea.

Twelve deaf patients with obliterated or ossified cochleas received the extracochlear version of the Vienna Cochlear Implant. Four patients, 1 of them a child, developed open speech comprehension. Obliteration of the cochlea could not always be predicted by conventional tomography of the temporal bone.

Holmium: YAG laser surgery in obliterated cochleas: an experimental study in human cadaver temporal bones.

A pulsed holmium:YAG laser (lambda = 2120 nm) was used to reopen the basal turn of artificially obliterated human cochleas in freshly dissected cadavers. This allowed intracochlear insertion of the stimulation electrode of a cochlear implant under simulated surgical conditions. Laser energy was transmitted through a 400-microns nylon fiber via the opened facial recess directly to the round window niche.

Multichannel stimulation of phrenic nerves by epineural electrodes. Clinical experience and future developments.

Between 1983 and 1992, 23 patients with complete ventilatory insufficiency of differing etiologies were treated with an eight channel implant (Medimplant Inc., Vienna) for fatigue free stimulation of both phrenic nerves. Data for 15 patients with high spinal cord lesions (ages: 9-51 years) are summarized: 1) level of lesion: C0, 3 patients; C1/C2, 4; C2/C3, 8; 2) time between incident and implantation: 3-14 months; 3) diaphragm training: 1-22 months; 4) chronic pacing: 5-83 months; 5) tracheostomy closed: 7 patients; 6) living permanently at home: 13 patients; 7) respiratory rate per minute: 12-17; 8) duration of inspiration: 1.

[Chondromatous tumors of the larynx based on three case reports with special reference to magnetic resonance tomography].

Cartilaginous tumours of the larynx are rare, altogether about 250 cases being reported in the literature. These tumours typically grow slowly and malignant types usually show only local infiltrative growth. Distant metastases are rarely observed.

[Manifestation of malignant lymphomatous polyposis of the nasopharynx].

A 66 year old male patient with malignant lymphomatous polyposis of the gastrointestinal tract showed a manifestation in the nasopharynx. After 6 cycles of chemotherapy according to the CHOP-Scheme complete remission could be observed. 9 months after therapy no signs of recurrence were evident.

[Chondrosarcoma of the nose and paranasal sinuses. Status of diagnostic imaging and therapeutic concept].

Chondrosarcomas of the nose and paranasal sinuses are extremely rare. The present report deals with a case of chondrosarcoma situated in the ethmoid, destroying the cribriform lamina and infiltrating into the orbit. Diagnosis and therapy are discussed.

[Malignant lymphomatous polyposis of the gastrointestinal tract].

Two years after endoscopic excision of several polyps of the colon (histological examination revealing infiltration by a malignant non-Hodgkin lymphoma) a 67-year-old man was again found to have blood and mucus in his stool. Because local recurrence was suspected a coloscopy was performed. This revealed multiple polyps throughout the entire colon, predominantly in the sigmoid and rectum.

[Functional and electromyographic long-term results following primary microsurgical repair of the recurrent laryngeal nerve].

Six patients with unilateral recurrent nerve paralysis underwent phoniatric follow-up after neurolysis or primary microsurgical repair of the recurrent laryngeal nerve. Four patients were controlled by electromyography of the vocal muscle 14 to 80 months post-operatively. In six patients the paralyzed vocal cords were in median to paramedian position with sustained muscle tonus.

A laryngeal pacemaker for inspiration-controlled, direct electrical stimulation of the denervated posterior cricoarytenoid muscle in sheep.

Bilateral recurrent nerve palsies were induced in four sheep and unilateral nerve palsy in one sheep. Vocal cord abductions were achieved by direct electrical stimulation of the posterior cricoarytenoid muscles (PCMs). By means of the diaphragmatic myogram, respiratory synchronous activation of the glottis opening musculature was shown possible.

Laryngeal pacemaker: activity of the posterior cricoarytenoid muscle (PCM) and the diaphragm during respiration in sheep.

Electromyograms (EMG) of the PCM and the diaphragm were evaluated in 6 sedated female sheep. Corresponding pneumatograms were recorded simultaneously by means of thermocontrolled respiration flowmeter. Evidence was obtained on considerable intra- and inter-individual differences in the duration of respiratory cycles as well as PCM- and diaphragmatic activity.

Comparative histochemistry of human and sheep laryngeal muscles.

Four laryngeal muscles of human male, human female and sheep female cadavers were evaluated by histological, histochemical and quantitative techniques. The muscle fibre sizes showed significant differences between human male, female and sheep. Fibre diameters of male human laryngeal muscles were 2 to 4 microns larger than in female human and 11 to 13 microns larger than in sheep muscles.

Isomyosin changes after functional electrostimulation of denervated sheep muscle.

Isomyosin analyses by biochemical, immunochemical, and histochemical investigations have been carried out in five sheep following unilateral recurrent laryngeal nerve paralysis and direct functional electrostimulation of the denervated cricoarytenoid posterior muscle. Myosin light chains were identified by two-dimensional gel electrophoresis. Myosin heavy chains were analyzed by one-dimensional SDS-polyacrylamide gel electrophoresis.

Comparative anatomy of human and sheep laryngeal skeleton.

In a macroscopical study the dimensions of the adult laryngeal skeleton of man and sheep were compared. In both species the data for male and female were evaluated separately. In contrast to pronounced differences in size between male and female human larynges, the dimensions of both sexes in sheep proved to be very similar.

[A method for puncturing the deep neck muscles in humans].

The authors developed a method to puncture neck muscles by means of computer tomographic control, enabling the introduction of an electrode into the obliquus capitis inferior muscle, to investigate the particular role of neck muscles in posture and head movement.

[Functional electrostimulation of the denervated posticus muscle in an animal experiment: histo- and biochemical results].

Histochemical and biochemical investigations have been carried out in 2 sheep following unilateral recurrent laryngeal nerve paralysis and direct electrical stimulation of the denervated posticus muscles. The stimulation effect was determined histochemically (standard ATP-ase staining) and compared with the fibre pattern of normal posticus muscles. In addition, one-dimensional gel electrophoresis of myosin heavy-chain isoforms was carried out and correlated with the histochemical results.

[Central localization of motor components in the internal branch of the superior laryngeal nerve: a horseradish peroxidase study in the rat].

The central organisation of the internal branch of the superior laryngeal nerve was examined in the rat using the technique of intraaxonal transport of horseradish peroxidase (HRP). Application of HRP to the internal branch resulted in anterograde labelling of afferent nerve fibres as well as in retrograde labelling of perikarya within both motor nuclei of the vagus, i.e.

[Evaluation of real-time sonography in the pretherapeutic staging of malignant tumors of the tongue and mouth floor].

Based on our three years experience with about 200 transcutaneous real-time sonographies of the tongue and the floor of mouth, an assessment of the determination of size and site of 38 pretherapeutically examined malignant tumours (35 squamous cell carcinomas) was made. The patients were examined in reclined position, the head retroflected. Curved array transducers of 5 or 7.

[The pharmacodynamics of vecuronium on the musculature of the vocal cords and the ball of the thumb. Preliminary report].

During endolaryngeal microsurgery, an attempt was made to quantify laryngeal muscle relaxation by electromyographic recording of evoked responses from the vocal cord musculature in 5 patients. Both mechanographic and electromyographic recordings from the adductor pollicis were obtained simultaneously. Following a bolus dose of vecuronium (60 micrograms/kg, n = 3, and 100 micrograms/kg, n = 2), nearly total (97%-100%) suppression of evoked responses at the peripheral muscle site was observed; the vocal cords, however, did not show complete neuromuscular (nm) blockade, but rather varying degrees of nm depression ranging from 61%-92%.

[Differences in the neuromuscular blockade of the larynx and thenar muscles following relaxation with vecuronium].

To objectivate the clinical impression of different neuromuscular depression in the larynx- and limb-musculature, an attempt was made in 5 patients to quantify laryngeal muscle relaxation by electromyographic recordings of evoked responses from the vocalis muscle during endolaryngeal microsurgery. Mechanographic and evoked electromyographic recordings of the thenar muscles were obtained simultaneously. Nearly total suppression of evoked responses at the peripheral muscle site was observed after a bolus dose of either 60 micrograms/kg or 100 micrograms/kg of the nondepolarising muscle relaxant Vecuronium.