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Concept

Instrument chirurgical

Un instrument chirurgical est un outil ou un appareil spécialement conçu pour réaliser les actions spécifiques liées à une opération chirurgicale, telles que modifier des tissus biologiques ou fournir une manière de les visualiser. De nombreux instruments chirurgicaux existent, certains étant d'utilisation tout à fait générale, d'autres très spécifiques. Histoire Préhistoire Les instruments chirurgicaux existent depuis les temps préhistoriques. Des outils de craniotomie ont ainsi été découverts dans de nombreux sites datant du néolithique. Il est souvent considéré qu'ils étaient utilisés par les guérisseurs et sorciers pour libérer les mauvais esprits et soulager les maux ou les blessures de tête. Antiquité En Inde, les chirurgiens et médecins ont utilisé des instruments chirurgicaux sophistiqués depuis l'Antiquité. Sushruta (aux alentours de 500 av. J.-C.), connu comme le « père de la chirurgie », a probablement été le chirurgien le plus importan

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Le titane est l'élément chimique de numéro atomique 22, de symbole Ti. La variante titanium, bien qu'attestée en français depuis 1872, est considérée comme un anglicisme incorrect. Le titane appart

La chirurgie (du grec , formé à partir de , signifiant « main », et de , « travail ») est la partie de la thérapeutique qui implique des opérations internes ou des manœuvres externes sur les tissus,

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The course introduces the main classes of biomaterials used in the biomedical field. The interactions with biological environment are discussed and challenges highlighted. State of the art examples per type of material are discussed. Students will generate a biomaterial and study cell compatibility.

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Virtual Reality Based Simulation of Hysteroscopic Interventions

Gábor Székely

Virtual reality based simulation is an appealing option to supplement traditional clinical education. However, the formal integration of training simulators into the medical curriculum is still lacking. Especially, the lack of a reasonable level of realism supposedly hinders the widespread use of this technology. Therefore, we try to tackle this situation with a reference surgical simulator of the highest possible fidelity for procedural training. This overview describes all elements that have been combined into our training system as well as first results of simulator validation. Our framework allows the rehearsal of several aspects of hysteroscopy—for instance, correct fluid management, handling of excessive bleeding, appropriate removal of intrauterine tumors, or the use of the surgical instrument.

2008

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Cataract is the leading cause of blindness worldwide. The clouding of the human eye lens is called "Grauer Star" in German. In the industrialized countries this process of increased blindness is corrected by the surgical removal of the clouded lens and its replacement by a plastic lens (intraocular lens, IOL). Cataract surgery is the most frequent surgery worldwide. In Europe more than two million operations are performed annually. For the selection of an optimum replacement the refractive power of the lens is calculated from the radius of curvature of the cornea, the length of the eye and the anterior chamber depth. Therefore these data have to be measured before every surgery. Until now the length of the eye was measured exclusively by ultrasound in the clinical praxis. For this procedure the sound transducer has to be placed directly or via a water funnel onto the cornea. It was the aim of the work presented in this thesis to lay the framework for introducing into the clinical praxis a contact free optical length measurement of the eye. The basic parameters for the measurement were determined. Starting from the state of the art new solutions were found, implemented in a laboratory device, and tested clinically. A two-beam interferometer with light of short coherence length that had been developed at the University Vienna was analyzed and compared with the one-beam technique. Neglecting practical limitations due to the optical arrangement and assuming shot-noise limited detection the one-beam technique allows the measurement of reflected light that is a factor of two lower compared to the two-beam technique. From the point of view of detection both techniques are therefore equivalent. The advantage of the two-beam technique is its independence from the eye movement. Until now the two-beam technique utilizes for detection only 1 over 400 of the light reflected from the retina and 1 over 2500 to 1 over 4000 of the light reflected from the cornea. This causes the dynamic range to drop by 26 dB. Furthermore the noise of the electronics (excess noise) comes into play. In this work a novel concept for the optical configuration in the two-beam interferometer is presented. By using a diffractive lens cornea and retina are imaged simultaneously onto the detector and the losses of the light from the retina are minimized. The cornea is imaged with an efficiency of 5.6 per cent. In order to minimize the requirements on the patient the measuring time was shortened to 1 s. Therefore the scan speed was increased by a factor of four compared to the state of the art. In the laboratory device it fluctuated by 20 per cent. To keep the detection narrow band it was necessary to implement a signal processing that is largely independent of the scan speed. By using a synchronous demodulation of two 90 degrees phase-shifted channels that are added as vector quantities a filter with self-adjusting center frequency was created. Its bandwidth is 4 kHz with signal frequencies between 30 kHz and 90 kHz. This concept was realized as a compact slit-lamp head and tested clinically. A shot-noise limited detection with a dynamic range of 105 dB was achieved (input power 200 µW). On the healthy eye the signal-to-noise ratio was limited by the digitization range of 8 bit. On the eye with cataract the measuring was not limited by the degree of clouding any more. The optical lengths were determined along the line of sight. They agreed with the post operative results. In some cases refractive errors of more than 2 dpt would have been avoidable by determining the IOL from the measurement of the optical length of the eye. This technique allows a comfortable, contact free optical eye length measurement that works correctly in 95 per cent of all eyes with cataract. Additionally smaller post operative refractive errors can be achieved as compared with traditional techniques. These results were the basis for the development of the IOL-Master – a novel device for the cataract treatment – at the Carl Zeiss Jena GmbH. With this device all biometric data can be measured in a non-contact fashion and intraocular lenses can be calculated and selected.

EPFL2001

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Adjustable fixation system for neurosurgical devices

Rémi Charrier, David Haag, Jean-Philippe Thiran

The system comprises at least a support (5) to be attached to a patient by fixing means (4), said support having an outer thread (7), a first nut (9) with an inner thread (11 ) cooperating with said outer thread (7) and an anchor having a spherical bottom end (10) being placed between said support and said nut, a spherical head (15) said spherical bottom end and head being linked by a shaft, a second nut (16) having an inner thread (17) and intended to be screwed on an external device having a corresponding thread (31 ), such as a platform (20) or a surgical device (30), whereby the tightening of at least one of the nuts (9,16) on the support and/or on the external device allows to block the position of the anchor.

2012

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