A patient with a 1.5- to 2.5-cm tracheoesophageal fistula secondary to prolonged assisted ventilation and feeding by a nasogastric tube was operated upon by a transtracheal microsurgical approach. The advantages of this approach are as follows: (1) the surgery is not extensive and therefore does not cause much stress to the patient; (2) this technique avoids the necessity for a wide mediastinotomy or sternotomy and thoracotomy, and therefore averts the danger of a widespread infection with the highly antibiotic-resistant bacteria that are always present in these cases; and (3) there is no risk of damage to the recurrent nerve. The ENT surgeon who is well-trained and experienced in microsurgery should try this approach in selected cases first. If this method fails, other methods are still available.

Adult↗

PubMedDate not supplied

A model for closure of arterial vessels with special regard to the coronary arteries.

Explore the source record for details and available documents.

Arterial Occlusive Diseases↗

PubMedDate not supplied

[Protein concentration in the guinea-pig perilymph].

The protein concentration of the guinea pig perilymph was investigated systematically using a micro-modification of the method of Lowry et al. Perilymph of scala vestibuli and of scala tympani was obtained from living animals and immediately post mortem by various methods. In living animals it is especially difficult to obtain samples without blood contamination. Another problem in the obtaining of perilymph from living animals is the contamination of tympanic perilymph samples with cerebrospinal fluid. This contamination diminishes the protein concentration of perilymph to a high degree. When the subarachnoid space is opened suboccipitally before perilymph extraction, there is no significant difference between protein content in tympanic and vestibular perilymph. The mean protein concentration in both cochlea scales is about 150 mg/100 ml. When samples are extracted post mortem from animals perfused intra-arterially, mean values of protein are in the same range. Without perfusion of animals, the mean value of tympanic samples extracted post mortem is significantly higher. Causes of artefacts in perilymph investigations are discussed.

Animals↗

PubMedDate not supplied

The intratemporal course of the facial nerve and its influence on the development of the ossicular chain.

Analysis of the information obtained from more than 110 malformations of the external and middle ear operated upon by the author (Gerhardt) leads to speculation as to their course of development. Of particular interest are the varying types of stapes malformations and the influence of variations in the course of the facial nerve on the development and shaping of the stapes. In the light of clinical examples, an attempt was made to interpret the variations in the course of the facial nerve and certain forms of stapes and incus malformation on the basis of the developmental processes in the area of the skull base and of the brain.

Ear↗

PubMedDate not supplied

Electrocochleography (ECochG) and brain stem evoked response recordings (BSER) in the diagnosis of acoustic neuromas.

Evaluation of the auditory evoked responses has hitherto been the most important otoneurological method for early diagnosis of acoustic neuromas. ECochG enables to recognize serious damage to the first neurone. Criteria are: increased latency of the action potential (N1) and a low amplitude of the action potential relative to a high amplitude of the microphonic potential. BSER is a more sensitive indicator for functional deficiency in the first neurone, especially by evaluating interaural differences of the interpeak intervals (IPI) I-V and I-III. Problems arising when wave I cannot be clearly detected can be overcome by combining ECochG and BSER and evaluating the latency N1-V or perhaps in a better way by applying derivation of BSER between promontory and vertex. In 24 of 25 patients with indistinctly defined wave I in the standard recording, evaluation was possible in promontory BSER.

Audiometry, Evoked Response↗

PubMedDate not supplied

Cultivation of ethmoidal sinus ciliated epithelia.

Proceeding from the cultivation of human epidermal cells we succeeded in cultivating mucosal cells from ethmoidal sinuses and in characterizing them by scanning electron microscopy. In particular, the reaction of ciliated cells and goblet cells in vitro and their ability to reproduce were compared with the reaction of keratinocytes. Ethmoidal sinus cells show adhesion and spreading rates similar to those of skin cells; they proliferate faster (3 days up to monolayer) and differentiate in vitro to ciliated epithelia. It would seem possible to use them for lining of plastic prostheses for the respiratory tract.

Cell Differentiation↗

PubMedDate not supplied

Experimental in vitro and in vivo studies of epithelium formation on biomaterials seeded with isolated respiratory cells.

Extensive tracheal defects after intensive care medicine, trauma, or large resections in tumor surgery remain a major challenge in plastic and reconstructive surgery. Defects that cannot be satisfactorily treated by complicated and costly reconstructive techniques reveal a need for an alloplastic tracheal replacement. Recent experimental and clinical studies in the development of alloplastic tracheal prostheses proved that the lack of an epithelial lining on the luminal surfaces and inadequate biophysical properties and shapes of the prostheses were the main causes for failure of these prostheses. In this study a cell-seeding technique has been used. Adhesion, spreading, and differentiation of seeded mucosa cells on biomaterials in vitro were observed by scanning electron microscopy (SEM). Chemical properties and surface structure of the material influenced the differentiation process. Epithelium formation of incorporated tracheal prostheses was tested in animal experiments. Isolated respiratory cells were seeded into implanted tubular prostheses of porous polyurethane or expanded polytetrafluorethylene. Light microscopy and SEM showed the tendency of epithelium formation on the surface of the lumen. Vigorous cell layers, predominantly as multiple cell layers of squamous epithelium, were observed. Ciliated or mucus cells were not detected. It can be stated that the epithelium formation on incorporated porous implants is possible. Further studies of the stability and the differentiation process of the epithelium on such implants is needed before an introduction of tracheal replacements into the clinical practice can be considered.

Biocompatible Materials↗

PubMedDate not supplied

[Protein concentration of perilymph in guinea pigs after noise exposure].

The protein concentration in the perilymph of noise-exposed guinea pigs was investigated using a micromethod described previously. The animals were exposed to wide band noise at 140 dB for one hour unilaterally in a closed acoustic system. Perilymph was obtained after exposure at different intervals: immediately, 6 or 24 hours later. From animals exposed to noise, it is particularly more difficult to obtain perilymph without blood contamination than from normal ones. Even post mortem, it is difficult to obtain samples without blood contamination and without hemolysis, particularly from the scala tympani. Therefore, some animals were perfused intra-arterially with Ringer solution or with Infukoll M 40 before decapitation. After exposure to noise only a small increase in protein concentration of the perilymph can be detected in the noise-exposed ears of animals perfused intra-arterially. The difference in concentration is most distinct in samples extracted 6 hours after noise exposure had ceased. No reliable clue to the source of this protein could be obtained from these investigations.

Animals↗

PubMedDate not supplied

[The effects of methodical factors on the microphonic potential in the guinea pig cochlea with perfusion of perilymph].

The decreas in microphonic potentials detected from the round window (RMP) is negligible only if the bores are located very close to the round window, whereas it will increase with increasing distance from it. Only at pressures of more than +/- 30 cm water column, in rare cases even below that, will a sharp decrease in the RMP occur, possibly because of a lesion of either the oval or the round windown membrane. At a perfusion pressure above +5.6 cm water column, the perfusion liquid will enter the cerebrospinal fluid space. At a lower pressure the perfusion liquid is diluted by cerebrospinal fluid via the cochlear aqueduct. The perfusion speed of 1 to 50 mul/min has no effect on the function of the organ of Corti.

Action Potentials↗

PubMedDate not supplied

The Berlin cochlear implant--surgical concept.

The extent of channel interactions using monopolar extrascalar stimulation probably limits the number of independently acting electrodes of a cochlear implant to three. Comparison of psychoacoustic and histopathological findings led to the conclusion that stimulation of the neurons in the upper basal and the second coil is of greatest benefit to the patient. By using a middle fossa approach, access to the upper basal coil and the second coil is possible without destruction of middle ear structures. The danger of infection is probably reduced. Using an additional external round-window electrode, a device providing three different stimulating electrodes can be applied.

Cochlea↗