Surgery – Specula – Laryngoscope
Reexamination Certificate
2001-11-21
2004-01-13
O'Connor, Cary E. (Department: 3732)
Surgery
Specula
Laryngoscope
Reexamination Certificate
active
06676598
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a laryngoscope comprising a handle, a spatula arranged substantially transverse to said handle, and a coupling, wherein said spatula is detachably fixed to said handle by means of said coupling.
The invention relates specifically to such a laryngoscope further comprising an illumination light waveguide and an image waveguide, both of which being attached to said spatula, wherein said illumination light waveguide comprises a proximal end having an illumination light entry opening, and wherein said image waveguide comprises a proximal end having an image exit opening, wherein said illumination light entry opening and said image exit opening are arranged in the area of said coupling, and wherein said handle comprises, in the area of said coupling, an illumination light exit opening and an image entry opening which allow for an illumination light signal to couple from said handle into said illumination light waveguide, and for an image signal to couple out of said image waveguide.
A laryngoscope of that kind is generally known from EP 0 901 772 A1.
The image waveguide of the known laryngoscope, which might be designated as video-laryngoscope, serves for grabbing an image in the area of the distal end of said spatula, i.e. from a throat area of a patient, and for transmitting said image to an image displaying unit. The image displaying unit might be attached to the handle, but this is not necessary. In any case, however, the grabbed image signal has to be transferred over the separable coupling. This is achieved by coupling the image signal from the image waveguide arranged on the spatula into the image entry opening of an image grabbing system that is located in the handle.
Coupling an image signal from one image waveguide into another always causes losses in quality. As it has turned out, these losses are the less, the more exact the corresponding openings are aligned with respect to each other.
The laryngoscope known from EP 0 901 772 A1 comprises a catching fastener located in the region of the coupling, and ensuring that the laryngoscope spatula is connectable to an image grabbing unit, which is located in the handle, such that the region of the throat area, which is important for the operating physician, can always be imaged. However, any reduction of losses in quality as mentioned above is not guaranteed by this configuration, since the region which is important for the physician to be observed allows positional displacements in the range of several millimeters, whereas the image transmitting quality is already impaired at relative positional displacements of the two coupling openings in the range of several micrometers. Thus, a reduction of losses in quality requires a substantially higher positional accuracy.
From U.S. Pat. Nos. 5,846,186 and 5,800,344, video-laryngoscopes are known wherein the image waveguide is not led across the coupling, just in contrast to the laryngoscope mentioned at the outset. That is how losses in quality are avoided, since the image waveguide can be made in one piece. These laryngoscopes, however, complicate the handling for the physician due to the cables in the proximal region of the spatula.
It is therefore an object of the present invention to provide a laryngoscope of the type mentioned at the outset which provides for reduced losses in quality during image transfer, and which provides a simple handling at the same time.
SUMMARY OF THE INVENTION
This object is achieved with a laryngoscope as mentioned at the outset that comprises a centering element which automatically aligns the image entry opening and the image exit opening precisely to each other.
By means of such a centering element, a given adjustment of the coupling openings is not only fixed, but beyond that the absolute position of the coupling openings with respect to each other is guaranteed, in contrast to a catching fastener. From the technical point of view, displacement of the positions of the coupling openings is not only prevented after putting together the spatula and the handle, but, what is more, in putting together the handle and the spatula, an optimum alignment of the coupling openings is already attained. Thereby, the light entry opening and the light exit opening are always optimally arranged with respect to each other, and losses in quality are minimum when the image signal is coupled over.
Moreover, the laryngoscope according to this invention provides for the same easy handling as the laryngoscope mentioned at the outset. The object is therefore completely achieved.
In an embodiment of the invention, the centering element mechanically aligns said image entry opening and said image exit opening with respect to each other.
This feature provides for a simple and robust handling, in particular when connecting the spatula to the handle.
In a further embodiment, the centering element aligns the image entry opening and the image exit opening both in radial and in axial direction with respect to each other.
This feature is particularly advantageous with respect to the fact that not only a radial displacement of the openings allocated to each other, but also an axial displacement may cause deterioration in image quality. For attaining an optimum image quality, it is therefore advantageous to center the openings allocated to each other in every direction.
In a further embodiment, the centering element fixes said entry and exit openings with a variation in fitting of less than 0.5 mm, preferably less than 0.1 mm.
These dimensions have turned out to be advantageous in practical experiments in order to guarantee a constant image quality even during a rough handling of the laryngoscope, and during force impact, in particular in emergency situations.
In a further embodiment, the centering element comprises at least one cone and a corresponding counter cone, one of which being disposed at said handle and the other one at said spatula.
Such an embodiment has turned out to be particularly advantageous for the centering element, as it is simple and robust on the one hand, and it combines the advantageous features mentioned before on the other.
In a further embodiment, the centering element comprises an electronic image alignment unit.
In particular, an electronic image alignment unit can be realized by arranging an electronic image or frame grabber, e.g. a CCD-chip, in the handle of the laryngoscope, the light-sensitive, active area of which being larger than the area really required. In such a case, the electronic image or frame grabber is capable to catch the image signal transmitted by the image waveguide even, if the adjustment of the image entry and exit openings is not exactly maintained any more. By measures known per se from electronic image processing, the “true” image sector can be extracted then. The feature has the advantage, both if taken alone or in combination with a mechanical alignment element, that the image quality of the laryngoscope according to the invention can be constantly maintained, even if loads and forces are acting.
In a further preferred embodiment of the invention, the image entry opening and the illumination light exit opening are located in different coupling planes that are axially displaced with respect to each other.
This feature has the advantage that scattering of the illumination light signal into the image waveguide is prevented in a simple manner, whereby the image quality of the inventive laryngoscope is further improved.
In a further preferred embodiment, the coupling is a standard coupling for connecting laryngoscope-spatulas to handles.
In this connection, every coupling is considered as a standard coupling which has become so widespread among laryngoscopes that a considerable number of laryngoscopes operate with this coupling. The feature has the advantage that the spatulas and handles of the laryngoscopes being already in use can alternatively be combined with the spatula and the handle of the inventive laryngoscope, although the image displaying unit might not be used in this case.
Irion Klaus M.
Kocher Mark
Renner Martin
Rudischhauser Jürgen
Schwarz Peter
Karl Storz GmbH & Co. KG
O'Connor Cary E.
St. Onge Steward Johnston & Reens LLC
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