Biomedical subjects

E Flemming

Publications and source records attributed to E Flemming.

5 recordsLinked to original sources

PubMed1997

[Tactile sensor for tissue differentiation in minimally invasive ENT surgery].

BACKGROUND: In endoscopic surgery, stereoscopic vision and tactile information about tissue consistency are no longer available to the surgeon. METHODS: To compensate for these sensory deficits, various tissues can be characterized with an electromechanical sensor that records their resonance frequencies. In the future, the sensor will be integrated into surgical instruments, providing the surgeon with information about tactile properties of the tissue. We determined the impedance of tissues removed interoperatively (nasal polyps, lymph nodes, cartilage, bone) and different bony structures in a skull specimen. The examinations were carried out with an experimental setup and subsequently with a prototype of the tactile sensor. RESULTS: Resonance frequency increased with tissue hardness. Measurements with the experimental setup showed resonance frequencies for soft tissues between 15 and 30 Hz. We found that the bony septa of the ethmoid have a resonance frequency of 240-320 Hz and the thicker bony structures at the frontal skull base have a frequency of 780-930 Hz. Measurements of tumors in the upper aerodigestive tract showed that it is possible to differentiate between healthy mucosa, carcinomateous infiltrated mucosa, and carcinomateous undermined mucosa. In case of undermining tumor, the resonance frequency was one third higher than healthy mucosa. These results obtained with the experimental setup were reproduced with the tactile sensor prototype. CONCLUSIONS: The use of tactile information in endoscopic otolaryngological surgery may improve intraoperative tissue differentiation in the future. The safety of minimal invasive operations in head and neck surgery can be increased.

Endoscopes↗

PubMed1997

[Optics with natural appearing added illumination].

Today's endoscopes use a central frontal illumination which creates huge contrast, no visible shadows, and gives an unnaturally flat impression. In the SIMIC project, a new type of optics has been developed that uses additional illumination fibres ending 3 mm behind the front lens. This gives a more natural and spatial impression of the body cavity, causes shadows that are an improvement when approaching tissue with an instrument, reduces blooming in the foreground, and improves detail reproduction in the background.

Endoscopes↗

PubMed1996

[Minimally invasive ENT surgery. Progress due to modern technology].

Three fundamentals have to be fulfilled to optimize minimally, invasive surgery: three-dimensional imaging, free maneuverability of the instruments, sensorial feedback. Projection of two pictures from a stereoendoscope and subsequent separation with a LCD shutter allows three-dimensional videoendoscopy to be performed. A high-frequency shutter technique (100/120 Hz) presents pictures from the two video cameras to the right and left eye, respectively, so that the surgeon has spatial vision of the operative field. Steerable instruments have four component: a control unit, rigid shaft, steerable multi-joints, distal effector. The steerable multi-joints give two additional degrees of freedom compared to conventional rigid instruments in endoscopic surgery. For intuitive movements, however, an electronic control system is necessary that is comparable to the "master-slave" principle in remote technology. A remote manipulator system with six degrees of freedom is now available. Additionally, a multifunctional distal tip permits different surgical steps to be performed without changing the instrument. For better control of the instrument and the operative procedure tactile feedback can be achieved with appropriate microsensor systems. Recent projects suggest that an artificial sensor system can be established within the foreseeable future.

Endoscopes↗

PubMed1995

Using regions and indices in EPG data reduction.

This note describes how dynamic electropalatography (EPG) can be used for the acquisition and analysis of articulatory data. Various data reduction procedures developed to analyze the electropalatographic data are reported. Specifically, these procedures concern two interesting areas in EPG data analysis--first, the novel use of speaker-specific articulatory regions and second, the development of arithmetic indices to quantify time-varying articulatory behavior and reflect reduction and coarticulation.

Electric Stimulation↗

PubMed1990

The perilymphatic fistula: the end of an enigma?

While the existence of a perilymphatic fistula may be suggested on the basis of a patient's history and physical findings, at present the diagnosis can only be established by the identification of the actual fistula at the time of tympanotomy. In some cases, repeated reaccumulation of clear colorless fluid within the middle ear is interpreted as representing perilymph and has been considered to indicate the presence of a fistula that cannot be visualized. This subjective type of observation is made by the operating surgeon and is consequently subject to bias. At the present time there is no objective method, such as histopathology, to confirm the diagnosis of a perilymphatic fistula in this type of situation. As a result, there is some variation and controversy in the otology literature as to what surgical findings at tympanotomy should be considered as "proof" of a perilymphatic fistula. In this paper we will propose a new method for confirmation of the diagnosis of perilymphatic fistulas based on a unique biochemical property of perilymph.

Ear Diseases↗