Abstract:
The invention relates to a medical instrument, comprising a signal transmitter and at least one activating device for activating the transmitter which is provided on a transmitter unit which is separate from the instrument, wherein the transmitter unit is a unit which can be fastened to the exterior of the instrument. It also relates to a method for controlling a treatment-assisting medical software by means of a signal transmitter which is arranged on a medical instrument, wherein the instrument is positionally detected by means of a medical tracking system, and wherein the software assigns a different significance to the signal output by the transmitter depending on the position of the instrument.

Description:
RELATED APPLICATION DATA 
       [0001]    This application claims the priority of U.S. Provisional Application No. 61/173,648, filed on Apr. 29, 2009, which is hereby incorporated in its entirety by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a medical instrument comprising a signal transmitter and at least one activating device for activating the transmitter which is provided on a transmitter unit which is separate from the instrument. 
       BACKGROUND OF THE INVENTION 
       [0003]    A generic instrument of this type is known from EP 1 990 021 A1, wherein in this case, a separate transmitter unit is provided which can be inserted into a sealable interior receptacle of an instrument. Such a solution requires special instruments to be provided and is therefore relatively costly. 
         [0004]    Medical instruments such as are provided within the framework of the present invention can—in addition to their actual purpose as instruments—also be used to control treatment-assisting software. In computer-assisted surgery, the person performing the treatment is provided with different image outputs, in most cases by a navigation and/or tracking system in the operating theatre. These image outputs show patient data sets or at least parts of patient data sets, i.e. for example three-dimensional or sectional representations of parts of the patient&#39;s body. The patient data sets can be generated either by imaging methods such as for example CT or MR tomography, x-ray, ultrasound or fluoroscopy, or by imageless methods such as tapping a bone surface by means of a registered pointer tool, or using laser scanning. Within the framework of image assistance, it is also for example possible to show instruments or treatment devices in their positional relationship relative to the patient data, so as to visually assist the person performing the treatment. Depending on the progress of the treatment, it is often necessary to display a specific part of the software assistance on the screen output, namely the part comprising the functions which are currently required for the current step in the treatment. The software could also be said to consist of different “pages” which interchange in the course of the treatment. It is often necessary to select particular software pages during the treatment. In addition to the solution mentioned above, this is often also realized by means of an input apparatus such as a mouse or a keyboard or by means of a touch-sensitive screen. Foot switches, virtual keyboards or voice control systems are also known. Other “means of communication” are for example specific movements of tracked instruments, for example pivoting about a fixed point. 
       SUMMARY OF THE INVENTION 
       [0005]    Against this background, it is the object of the present invention to optimize the transmission of signals for communication and control in conjunction with medical instruments. The intention is in particular to make equipping an instrument with signal-transmitting functionality simpler and/or applicable to conventional instruments. 
         [0006]    This object is solved in accordance with the invention by a medical instrument comprising a signal transmitter and at least one activating device for activating the transmitter which is provided on a transmitter unit which is separate from the instrument, wherein the transmitter unit is a unit which can be fastened to the exterior of the instrument. The sub-claims define preferred embodiments of the invention. 
         [0007]    The invention is characterized in that the transmitter unit is a unit which can be fastened to the exterior of the instrument. In other words, a transmitter unit which can be placed on the instrument is provided, which makes equipping instruments with transmitter functionality significantly simpler. It is possible to provide transmitter units which can be fastened to conventional instruments easily and/or in simple steps, such that the need to provide special and therefore expensive instruments is removed. The invention is based inter alia on the recognition that the sterility of such instruments is not necessarily threatened if transmitter units are used which can be placed on the exterior of the instrument, and the reason for this is that such transmitter units can also be pre-sterilized in their entirety and in particular provided sterilely packaged. This enables a cost-effective solution without sterility problems; specifically, it is possible to circumvent the problems caused by hot-steam sterilization—which in practice is used the most—with electronic components and energy supply elements. 
         [0008]    In one embodiment of the present invention, a positionally defined fixing portion for the transmitter unit is provided on the instrument, while on the other hand, the transmitter unit can also comprise a fastening portion which can be fastened to the periphery of the instrument, in particular to such a fixing portion. 
         [0009]    In order to optimize handling, the transmitter unit can be able to be fastened by means of a releasable quick-release lock, in particular by means of a snap-on and/or plug connection. In accordance with one embodiment variant, it can be fastened using a fixing element which is arranged on the periphery of the instrument, in particular using a part of the instrument which can be detached and re-attached, specifically a reference marker which can be attached to the instrument. 
         [0010]    The transmitter unit can include different functional elements, including: an optical transmitter, specifically an LED, in particular an infrared LED; and an activating switch, specifically a contact switch. In addition, an optical status signal emitter, in particular a status signal LED, can also be provided. 
         [0011]    It is possible to embody the medical instrument such that the transmitter unit comprises an integrated energy supply for the transmitter, in particular a battery, specifically a button cell battery. 
         [0012]    In a particularly preferred embodiment, the transmitter unit is provided as a disposable item, specifically as a sterilely pre-packaged disposable item which can for example be provided in situ in the operating theatre in a tear-open pack. Modern production methods allow such disposable items to be cost-effectively produced, for example substantially or mainly (predominantly) from a plastic material, and in operating theatres—in which sterility is an extremely important condition—such a practice is perfectly justified and is already used in various ways. 
         [0013]    In accordance with another aspect, the present invention relates to a system of instruments comprising: a plurality of instruments such as are described here in different embodiments, wherein the instruments comprise standardized fixing portions which can fasten the same transmitter unit and/or a transmitter unit via identical standardized fastening portions; and at least one separate transmitter unit. This embodiment variant enables the invention to be used universally with many different instruments. 
         [0014]    Another aspect of the present invention relates to a method for controlling a treatment-assisting medical software by means of a signal transmitter which is arranged on a medical instrument. The medical instrument is positionally detected by means of a medical tracking system, and the software assigns a different significance to the signal output by the transmitter depending on the position of the instrument. 
         [0015]    This system, in which instruments such as are described and claimed here can be used, enables a broad communications base and the transfer of different, even complicated control commands on the one hand, and on the other hand enables signal transmitter units to be held in a very simple way, since the invention envisages that the signal does not necessarily have to be changed in order to relay different commands, but rather it is merely necessary to simply change the position of the instrument on which the signal emitter is currently situated. Because such instruments, for example pointers, can be relatively simply moved to certain positions by the physician performing the treatment, the present invention enables a wealth of signals to be transferred by equipping an instrument in a simple way and/or using a simple transmitter. 
         [0016]    In a specific embodiment of the method in accordance with the invention, at least one spatial region is defined within the detection range of the tracking system, in particular in the vicinity and/or environment of a tracking reference, wherein the signal output by the transmitter is given a particular significance by the software when the instrument interacts with this spatial region, in particular when the tip (or a particular part) of the instrument is situated in this spatial region. 
         [0017]    It is also possible to transmit an instrument identification signal or code by means of the signal transmitter, which can make initializing (and/or calibrating) the instruments, for example for an operation-accompanying medical navigation system, much simpler. 
         [0018]    In accordance with other aspects, the invention relates to a program which, when it is running on a computer or is loaded on a computer, causes the computer to perform a method such as is described here, and to a computer program storage medium comprising such a program. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The invention is explained below in more detail on the basis of an embodiment. It can comprise any of the features described here, individually and in any combination, and can in particular also be regarded as the use of a separate signal transmitter, which can be placed on the exterior of the instrument, for software control. 
           [0020]      FIGS. 1 to 3  show an embodiment of a transmitter unit in accordance with the invention. 
           [0021]      FIGS. 4 and 5  show a medical instrument equipped with a transmitter unit. 
           [0022]      FIGS. 6 and 7  show two embodiments for transferring signals in accordance with the position of the instrument. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In the enclosed drawings, an embodiment of a transmitter unit in accordance with the invention is indicated by the reference sign  1 . It comprises a body including a fastening portion  2  and an extension and/or LED support  3  which comprises a signal LED  5  and a status LED  4 . Opposite the support  3 , the activating switch  6 —in this case, a contact switch—is attached to the fastening portion  2 . The switch  6  can be any switch, including for example a push-button switch. 
         [0024]    A cavity  9  is provided in the lower part of the support  3  for a button cell battery  8  which provides the energy supply for emitting signals through the LEDs  4 ,  5 . A passage  7 —in this case, a circular hole—is situated in the upper part of the fastening portion  2 . The aforesaid component designations can in particular be gathered from  FIGS. 1 to 3 . 
         [0025]      FIGS. 4 to 7  show an instrument  10  which comprises an instrument grip  11  and a tip  13  and which is embodied as a pointer and/or pointing apparatus. The grip has a corrugated portion  12  at which it can be securely held, and three reference markers  14 , and  18  protrude upwards out of the grip and serve as tracking markers for a medical tracking system  31  which comprises two tracking cameras which are schematically shown in  FIGS. 6 and 7  but not separately indicated. The foremost tracking marker  18  is shown in more detail in  FIG. 4  and comprises the protruding marker holder  16  and the marker sphere  17  on the fixing portion  19 . As can be gathered from  FIGS. 4 and 5 , the transmitter unit  1  in this embodiment is plugged onto the marker holder  16  using the transit hole  7  and then onto the fixing portion  19  and is fixed and/or secured against being unintentionally lost by screwing-on the marker sphere  17 . 
         [0026]      FIGS. 6 and 7  also show different defined spatial regions  40 ,  41 ,  42  and  43  which are formed and/or defined around tracking references  30  and/or  35 . The subsequent description of the invention will now be based on said figures and designations. 
         [0027]    Like any standard navigation instrument comprising passive tracking technology, the instrument  10  also has reflection markers  14 ,  15  and  18 , and these markers and/or their reflective spheres (for example,  17 ) reflect emitted infrared light and are thus positionally detected by the tracking system  31 . Conventional navigation systems use these position data as three-dimensional position information for particular marker geometries and assign it to particular instruments, such that the navigation system always for example knows where the front end of the tip  13  of the instrument  10  is situated. 
         [0028]    The transmitter unit  1  in accordance with the present invention, which can be regarded as an active input device for software control, is fastened to an instrument marker  18  on the instrument  10  as shown in  FIGS. 4 and 5  and as already described above. In this position, the switch  6  can easily be reached by a finger; when it is activated, the infrared LED  5  emits an infrared light signal for software control, which is for example detected by the tracking system  31 , and the LED  4  emits a visible light signal as a confirmation or status signal, so that the user knows that the invisible infrared signal of the LED  5  has indeed also been transmitted. As already indicated above, the power supply for this is provided by the button cell  8  in the battery holder  9 . 
         [0029]    The transmitter unit  1 , which in this case is produced from plastic as a disposable item, is advantageously designed such that it can be attached symmetrically, such that it can be attached to the instrument universally for right-handed or left-handed operation, i.e. with the support extension  3  aligned in one or other direction of the instrument body, away from its longitudinal axis. In the preferred embodiment, the transmitter unit  1  is attached at a defined position on the navigated instrument  10 , namely to the fixing portion  19 , such that the software can identify the positional range of the infrared LED support signal, which is stored in the navigation system together with the geometric information about the instrument  10 . 
         [0030]    When the activating switch  6  is activated, the infrared LED signal of the diode  5  is activated. During this “active mode”, the LED  5  is tracked by the tracking cameras of the tracking system  31 , and the signal emitted is used to control a software functionality of the navigation system, for example as a confirmation signal. 
         [0031]    The positional accuracy of the infrared LED  5  is then less important, because only the more exactly positioned passive markers  14 ,  15  and  18  reference the instrument geometry. For this reason, the transmitter unit can be designed very simply and cheaply, as a sterile disposable item. In another embodiment, active trigger signals could be used to digitize registration points on objects, for example bone surfaces, without having to generate additional trigger movements or other trigger signals. 
         [0032]    With respect to applicability, active disposable transmitter units in accordance with the invention can be universally used in combination with any possible existing passive instruments and pointing apparatuses (pointers), and already-existing passive pointer apparatuses can therefore be equipped and/or augmented with active control functionalities. The transmitter units could also be embodied to be compatible with other passive navigated instruments, for example drill guides, cutting blocks, awls, broaching tools, etc., wherein they would likewise be fastened (as disposable items) to these instruments and detached again after use. If such sets of instruments are provided, they could have specifically assigned and embodied interfaces for attaching the universal disposable transmitter units. Other technical features can be integrated, such as additional infrared LEDs, wireless RF communications modules or a plurality of control buttons, which would increase functionality even further, in particular also with regard to the software interaction for standard passive instruments. 
         [0033]    Another aspect of the invention, which may be referred to as non-contact software workflow control, shall now be explained in more detail by referring specifically to  FIGS. 6 and 7 . During medical navigation, reference arrays  30 ,  35  are usually provided and fastened to the patient, in order to be able to reproduce the patient&#39;s movements and integrate them into navigation. On the basis of these reference geometries  30 ,  35  (or also on the basis of other reference geometries provided), it is then possible to determine pre-defined virtual spatial regions which can serve as a remote control for using the instrument. If, for example, a pointed end of a navigated instrument is introduced into such a remote control region, for example the region  40  around the reference array  30  in  FIG. 6 , a particular “remote control mode” for the software is launched. 
         [0034]    In the case of “one-button” control, the user can then control functionalities of the active transmitter unit in order to communicate simple commands such as “next”, “back” or “select”. Thus, “next” functions can for example be assigned to short signals (less than 0.5 seconds), while activating the switch  6  for longer (more than one second) can be classified and pre-defined as a “back” command, when the tip  13  of the pointer instrument  10  is situated in the virtual region  40  around the reference array  30 . If a different function, for example a “select” function, is then required, the user can remove the front end of the tip  13  from the virtual region  40  around the reference array  30 , and when the tracking and navigation system determines that this tip end is not situated in the region  40 , a different command is assigned to activating the switch  6 , for example a “select” command. Subsequent clicks on the active input device  1  would then for example confirm, select, activate or digitize reference points on parts of the patient&#39;s body. Using a “sustained” activation of the button and/or signal emitter, it is also possible to register multiple surfaces, wherein the tip of the pointer instrument is guided over the surface to be registered, and the software ensures that points are not repeatedly recorded. 
         [0035]    The remote control regions  40  in accordance with the invention are situated in a freely defined and definable space around the reference array  30 . 
         [0036]    Another embodiment, shown in  FIG. 7 , provides for sub-dividing the remote control region into three free regions  41 ,  42  and  43  between the arms of the reference star  35 . Each region then has a different functionality when the pointer tip is introduced into it, and corresponding functionalities can be accessed by pressing the activating switch  6 , wherein the tip of the pointer can remain spatially free and does not have to contact the reference star  35  at predetermined or pre-defined locations, such that shifts in references and resultant registration inaccuracies are avoided. 
         [0037]    The embodiments of the present invention thus enable a non-contact, wireless and very comfortable interaction between the person performing the treatment and a software of a navigation system. The person performing the treatment controls the functionalities of the system by using a navigated instrument in the sterile environment. By assigning an active interaction device to the passive navigated instrument, the range of possible methods is extended and allows a greater variety of control inputs (for example, during registration), without having to perform the movements or perform separate selecting or confirming controls. The transmitter unit can be placed, as a disposable item and active auxiliary element, onto existing passive navigated instruments (for example as a clip), and it is thus possible to avoid problems which arise, due to integrated electronics, when heat and steam are used in sterilizations. 
         [0038]    The advantages of the invention in general and of different specific embodiments of the invention can also be listed as follows: 
         [0039]    an intuitive interaction between the user and the software/computer system is possible; 
         [0040]    objects can be registered in the navigation system more comfortably, easily and quickly; 
         [0041]    slipping during object registration, for example bone registration, can be avoided because confirming movements are avoided (pivoting); 
         [0042]    it becomes possible to optimally align reference arrays for the best possible recognition/accuracy during registration (pivoting movements through regions with restricted visibility is not required); 
         [0043]    user flexibility is provided; 
         [0044]    a simple instrument design is possible; 
         [0045]    there is no need for autoclaving, such that damage to electronic components and energy supply elements can be avoided; 
         [0046]    there is compatibility with existing passive instruments, such as for example pointers; and 
         [0047]    any passive instrument can be upgraded with additional active functionalities. 
         [0048]    Computer program elements of the invention may be embodied in hardware and/or software (including firmware, resident software, micro-code, etc.). The computer program elements of the invention may take the form of a computer program product which may be embodied by a computer-usable or computer-readable storage medium comprising computer-usable or computer-readable program instructions, “code” or a “computer program” embodied in said medium for use by or in connection with the instruction executing system. Within the context of this application, a computer-usable or computer-readable medium may be any medium which can contain, store, communicate, propagate or transport the program for use by or in connection with the instruction executing system, apparatus or device. The computer-usable or computer-readable medium may for example be, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared or semiconductor system, apparatus, device or medium of propagation, such as for example the Internet. The computer-usable or computer-readable medium could even for example be paper or another suitable medium on which the program is printed, since the program could be electronically captured, for example by optically scanning the paper or other suitable medium, and then compiled, interpreted or otherwise processed in a suitable manner. The computer program product and any software and/or hardware described here form the various means for performing the functions of the invention in the example embodiment(s). 
         [0049]    Although the invention has been shown and described with respect to one or more particular preferred embodiments, it is clear that equivalent amendments or modifications will occur to the person skilled in the art when reading and interpreting the text and enclosed drawing(s) of this specification. In particular with regard to the various functions performed by the elements (components, assemblies, devices, compositions, etc.) described above, the terms used to describe such elements (including any reference to a “means”) are intended, unless expressly indicated otherwise, to correspond to any element which performs the specified function of the element described, i.e. which is functionally equivalent to it, even if it is not structurally equivalent to the disclosed structure which performs the function in the example embodiment(s) illustrated here. Moreover, while a particular feature of the invention may have been described above with respect to only one or some of the embodiments illustrated, such a feature may also be combined with one or more other features of the other embodiments, in any way such as may be desirable or advantageous for any given application of the invention.