Sterile cover for a medical navigation tracker, medical navigation tracker, and sterile cover system

Abstract

The present disclosure relates to a sterile cover (1; 101) for covering at least part of the periphery of a medical, in particular surgical, navigation tracker (2; 102), in particular for fitting over the navigation tracker. In addition, the invention relates to a navigation tracker and to a sterile cover system according to the additional independent claims.

Description

[0001] Sterile cover for a medical navigation tracker, medical navigation tracker, and sterile cover system

[0002] Description

[0003] Technical area

[0004] The present disclosure relates to a sterile cover for a medical navigation tracker for covering or encasing a medical, in particular surgical, navigation tracker, with a cover that is at least partially transparent. Furthermore, the present disclosure relates to a medical navigation tracker and a sterile cover system comprising a navigation tracker and a sterile cover according to the preambles of the independent claims.

[0005] Background of the present disclosure

[0006] A basic requirement for robot-assisted surgical procedures is the precise recording of the position of a patient currently positioned in the operating room, relative to any available preoperative images, such as CT or MRI scans, as well as to a robot-guided or robot-actuated end effector, in particular to a surgical instrument currently in use.

[0007] To track the position of the patient or an end effector, rigid bodies with navigation markers, so-called navigation trackers, are usually attached to the patient or end effector. These markers can be spatially tracked by a camera of a tracking system. The navigation trackers usually have a large number of navigation markers arranged in a geometrically rigid manner relative to one another, which can be designed actively as LEDs or passively as reflector markers. The use of passive infrared (IR) reflector markers with a number of at least three, in particular at least four, reflector markers has proven particularly advantageous for determining a position. Of course, a higher number of five or six or more is also possible, with the accuracy and process reliability of determining the position increasing with the number of reflector markers.

[0008] In the passive case, a source emits infrared radiation, which is reflected by the IR reflector markers. The position of the reflector markers of navigation trackers mounted on instruments or pointers is stored in a predefined navigation system, so that when used, the position of the instruments or pointers relative to the camera origin can be easily determined.

[0009] In preparation for surgery, the patient must be registered. For this purpose, a non-sterile patient navigation tracker is firmly connected to a bony structure of the patient, for example, the patient's head, via a holding device, such as a clamp, and a patient tracking arm. Furthermore, prominent points or positions on the head are scanned using a pointer, which is also equipped with a navigation tracker. The prominent points thus captured on the patient by the tracking system's camera are then matched or mapped with the same prominent points present in the preoperative CT or MRI images, thereby registering the current patient in the operating room with reference to their preoperative images. The preoperative images and the patient are thus superimposed in the correct position and can be visualized in the correct position.The position of the head can then be recorded in real time (spatially) using the non-sterile patient navigation tracker and the camera, since the registration process and matching with the CT or MRI image is complete.

[0010] To perform the surgery, the patient is typically draped sterilely, with only the surgical site accessible through an opening in a sterile drape. The patient tracker must also be sterile, as it is located in the surgical area and must be tracked intraoperatively. Typically, the non-sterile patient tracker previously used for registration is replaced with an identical, sterile patient tracker. However, since navigation trackers are never truly identical due to their tolerances, this step leads to a loss of navigation precision.

[0011] Alternatively, the non-sterile patient tracker can be left in place and covered with a transparent, sterile drape instead. This option is known for active navigation markers according to US 2014 031 85 51 A1. However, the risk of tracking errors is relatively high even with active navigation markers due to wrinkles or excessive distance to the LEDs. Active trackers also have disadvantages due to their required power supply. Applying this solution to passive navigation trackers poses an even higher error potential.

[0012] WO 2017 144 115 A1 shows a similar solution, in which the sterile cover sleeve is additionally provided with deep-drawn recesses into which the navigation markers of the navigation tracker are inserted. If the positions of the deep-drawn recesses do not sufficiently match those of the navigation markers, a loss of accuracy also occurs.

[0013] Summary of the present disclosure

[0014] It is therefore the object of the present disclosure to avoid or at least mitigate the disadvantages of the prior art and in particular to provide a sterile cover sleeve that ensures particularly simple and secure covering or encasing of a navigation tracker, as well as precise tracking of the navigation tracker, as well as to provide a navigation tracker that ensures its precise tracking when a sterile cover sleeve is thrown over or covered with it, as well as to provide a sterile cover system comprising a navigation tracker and a sterile cover sleeve that provides simple and secure covering or encasing of the navigation tracker and its precise tracking.

[0015] The objects of the present disclosure are achieved with respect to a sterile cover sheath by the features of claim 1, with respect to a navigation tracker by the features of claim 17, and with respect to a sterile cover system by the features of claim 23. Further developments of the respective invention are described in the dependent claims.

[0016] A basic idea of ​​the present disclosure provides for the use of a sterile cover sleeve for at least partially covering or enclosing a non-sterile medical, in particular surgical, navigation tracker, for a sterile cover or sheath. The navigation tracker can in particular be a patient tracker, an instrument tracker, or a robot tracker and preferably have a plurality of navigation markers, in particular three or four. The navigation markers can all be arranged in one (virtual) plane. The navigation markers can all be arranged in different (virtual) planes. The navigation markers can be partially (i.e., at least two, but not all navigation markers) arranged in a common (virtual) plane and partially (i.e., at least two, but not all navigation markers) arranged in different (virtual) planes.

[0017] According to one aspect of the present disclosure (which can also be claimed independently), the sterile cover sleeve has at least one transparent sleeve section.

[0018] Preferably, the transparent casing section can be dimensionally stable.

[0019] Preferably, the transparent casing section may have a shape suitable for receiving only individual navigation markers of an array at their bases.

[0020] Preferably, the sterile cover sleeve can comprise at least two transparent, dimensionally stable sleeve sections, each serving to accommodate a single navigation marker of a navigation tracker, as well as a flexible sleeve section by which the transparent, dimensionally stable sleeve sections are connected to one another. This means that the flexible sleeve section is arranged between the dimensionally stable sleeve sections, or the dimensionally stable sleeve sections are not connected to one another in a dimensionally stable manner.

[0021] Preferably, the transparent casing section can be transparent for a specific wavelength range, in particular for infrared radiation (i.e., is permeable for this wavelength range) in order to cover a navigation marker of the navigation tracker in a transparent, in particular detectable, manner for this wavelength range.

[0022] According to a preferred embodiment, the sterile cover wrap may comprise at least one absorbent wrap portion.

[0023] The absorbent casing section can preferably be absorbent for the specific wavelength range, in particular for infrared radiation, in particular for a wavelength above 780 nm, in order to minimize or even prevent reflections for this wavelength range, in particular in an area of ​​the navigation tracker to be covered by the absorbent casing section. By means of the absorbent casing section, unwanted reflections are minimized or even prevented in an area adjacent to the navigation markers, so that the recognizability and detection of the navigation markers is not negatively affected in this regard. The navigation markers, on the other hand, are covered transparently and are therefore defined and easily detectable. One can also say that on the basis of the specific wavelength range, a first material of the transparent casing section is selected such that it is transparent oris permeable in order to keep the navigation markers covered by the transparent casing section (optically) detectable in this wavelength, and a further, different material is selected for the absorbent casing section, which is designed to be absorbent for this wavelength in order to avoid unwanted reflections as far as possible. For example, for the wavelength range of visible light, a plastic that is transparent (in the visible range) can be selected as the transparent casing section and a dark-colored nonwoven fabric can be selected as the absorbent casing section. According to a further development, the absorbent casing section is dimensioned, in particular in its surface area, such that at least one support structure of the navigation tracker, which supports the navigation markers, can be covered, in particular is covered, by it.While the transparent shell sections cover the navigation markers, the absorbent shell section covers the remaining support structure of the navigation tracker, which only serves to mechanically connect and hold the navigation markers, but not for tracking itself.

[0024] Preferably, the absorbent cover portion can be formed at least partially with a loose shape, in particular from a drape, a cloth, a nonwoven fabric, or a film. Alternatively or additionally, the absorbent cover portion can be formed at least partially with a stable shape, in particular from a plate.

[0025] To allow a user to see the covered or encased navigation tracker, according to a further development, the casing section designed to be absorbent for the specific wavelength range, in particular for IR radiation, is designed to be transparent for visible light, i.e., for wavelengths from approximately 280 to 750 nm. In other words, the absorbent casing section is opaque or absorbent for the specific wavelength range, in particular for IR radiation (in particular from a wavelength greater than 780 nm), but permeable or transparent for visible light. In other words, the absorbent casing section can be absorbent for a first specific wavelength range and transparent for a second specific wavelength range.Alternatively, the sheath section designed to absorb the specific wavelength range, in particular IR radiation, can preferably be designed to be opaque or non-transparent to visible light.

[0026] According to a further development, the sheath section absorbing the specific wavelength range, in particular IR radiation, has at least one recess into which the at least one sheath section transparent to the specific wavelength range, in particular IR radiation, is inserted. In this way, the absorbing and the at least one transparent sheath section can be manufactured separately from one another, and the sterile cover sheath can subsequently be assembled and connected by inserting the at least one sheath section transparent to the specific wavelength range, in particular IR radiation, into the associated recess. In this way, a multi-part, yet closed and continuous cover or enclosure is realized.

[0027] According to a preferred development, the at least one sheath section transparent to the specific wavelength range, in particular to IR radiation, has a circumferential collar or flange with a greater width or dimension, in particular a larger diameter, than the recess. The collar or flange is connected to an edge or edge region of the recess, in particular by means of a material bond, in particular by means of an adhesive bond or ultrasonic welding connection, in order to form a hermetic connection. In this way, a cover sheath, although manufactured from multiple parts, nevertheless forms a seamless sterile barrier after connection. In particular, this makes production and assembly even simpler, more effective, and more cost-effective.

[0028] According to a further development, the at least one casing section, which is transparent for the specific wavelength range, in particular for IR radiation, extends at least partially in a hollow cylinder and has an opening at one end section, in particular bordered by the collar or flange, for inserting one of the navigation markers. At another end section, it has a dome / cap, in particular a partially spherical or semi-spherical or aspherical, for example, elliptical or cylindrical, for at least partially concentrically receiving and covering one of the navigation markers. In other words, the at least one casing section, which is transparent for the specific wavelength range, in particular for IR radiation, has a hollow cylindrical section extending from a collar or flange, which is closed at the end by a spherical hemisphere or aspherical cap.The partially spherical, semi-spherical or aspherical, for example elliptical or cylindrical, dome / cap interacts in a self-centering manner with a preferably spherical navigation marker, so that the navigation marker is concentrically embedded in the dome / cap, which makes the detection of the navigation marker by a tracking camera very precise.

[0029] According to a further development, the at least one casing section which is transparent for the specific wavelength range, in particular for IR radiation, for receiving ( / covering) one of the navigation markers has a cap shape, hat shape or knob shape, preferably a melon hat shape. A cross-section of the casing section can be substantially circular. The cross-section can taper outwards, i.e. have the shape of a circular segment, an oval segment or an elliptical segment in longitudinal section, or remain constant, i.e. be rectangular in longitudinal section. These shapes prove to be advantageous in particular for navigation markers which have a spherical head or a disk head, since the one which is received therein and to be covered thereby, said casing section closely follows a contour of the spherical head.

[0030] Preferably, the at least one casing section that is transparent for the specific wavelength range, in particular for IR radiation, is made of transparent plastic, in particular PETG, PC, PS, for example PS165N, or PMMA. The plastic design enables efficient manufacturing processes for this casing section, so that according to a preferred embodiment, it is deep-drawn or plastic-injected. Particularly in the case of uneven wall thicknesses, the caps can be produced by injection molding. Uneven wall thickness on the caps can significantly influence the accuracy depending on the position relative to the IR light source. According to one embodiment, it does not have to be made entirely of plastic, but can contain a proportion of plastic.

[0031] In particular, the casing section which is transparent for the specific wavelength range, in particular for IR radiation, is designed in the form of a rigid covering cap which is adapted to be plugged or pulled over the navigation marker and in particular has a circumferential flange at the end which is arranged radially outward, said flange being connected to the casing section which is absorbing for the specific wavelength range, in particular for IR radiation, by means of a material-to-material connection, in particular an adhesive connection, particularly preferably by means of a double-sided adhesive tape.

[0032] In particular, the flange is designed as a radially outer ring section around the circumference of the cover cap and the ring section is connected to the sleeve section absorbing the specific wavelength range, in particular for IR radiation, at the top or bottom as seen in the longitudinal axis direction of the cover cap, in particular in a materially bonded or form-fitting manner.

[0033] In particular, the cover section absorbing the specific wavelength range, especially IR radiation, is designed as a drape, in which a cross cut is provided for each cover cap, into which the cover cap is inserted. The cover cover thus formed can be provided particularly cost-effectively and flexibly by users on-site, especially when designed as a disposable item.

[0034] According to a further (also independently claimable) aspect of the present disclosure, a sterile cover sleeve is used for a sterile covering of a non-sterile navigation tracker. This cover sleeve can be thrown or placed over the navigation tracker, or is thrown or placed over the navigation tracker, and which, given the rigidity of its sleeve, has a sufficiently high inherent weight that it tightens itself over the navigation markers of the navigation tracker intended for tracking or detection through the effect of gravity, in other words, automatically and without additional force. For this purpose, a weighted section of the cover sleeve is provided with reference to a transparent section of the cover sleeve that can be pulled smooth or tight.This weighted section defines a cover opening through which the navigation tracker is inserted into the cover when slipped over it, or in other words, through which the navigation tracker is inserted into the cover when the cover is slipped over the navigation tracker. Under the effect of gravity, this weighted section subsequently pulls the cover taut or flat over the navigation markers, with or without a gap, so that disruptions caused by draping are no longer in the line of sight of a camera of a tracking or tracking system, ensuring precise tracking of the navigation tracker's navigation markers.

[0035] One could also say that the navigation tracker can be inserted into the sterile cover. The design of the cover is particularly suitable for inserting and receiving a navigation tracker during relative movement of the navigation tracker to the sterile cover. In practice, the procedure is usually such that the navigation tracker is rigidly attached and the sterile cover is placed over it, or can be placed over it.

[0036] In a specific embodiment, the sterile cover sheath or sleeve is intended for sheathing or wrapping a medical, in particular surgical, navigation tracker. This can in particular be a patient tracker, an instrument tracker, or a robot tracker. In a preferred application, the sterile cover sheath serves to sheathe or wrap a navigation tracker to be attached to the patient. The sterile cover sheath has a sheath that is at least partially transparent and a sheath collar, wherein the sheath and the sheath collar are designed and dimensioned such that the navigation tracker can be accommodated. For this purpose, the sheath collar, in an unloaded state, provides / limits or defines a sheath opening that is sufficiently dimensioned and shaped for the navigation tracker to be passed through.In particular, the navigation tracker can advantageously be inserted through the cover opening predetermined in the unloaded state (i.e., without manual elastic compression, for example) (without adjusting the cover, as in the case of a cover similar to an inside-out plastic bag with an undefined opening). In particular, the cover collar is stiffened to a certain degree, for example through material and / or dimensioning, in order to define the cover opening. According to the disclosure, the cover collar is or has a weight, in particular it has a higher density than the cover, so that when the cover is thrown over the navigation tracker, the cover is tightened by gravity due to the weight of the (cover) collar. In other words, the weight of the cover collar is greater than a deformation force of the cover required to tighten the cover (at least in part).Preferably, the density of the enveloping collar is greater than that of the casing to be tightened. The enveloping collar is preferably made of cardboard, a plastic, or a metal, such as sheet metal.

[0037] In this way, a sterile cover is created through which a navigation tracker can be covered in a particularly simple and secure manner, namely by simply throwing it over, while still providing precise tracking of the navigation tracker, since the weighting under the effect of gravity, i.e. in principle automatically, enables the cover to be tightened over the navigation markers.

[0038] Advantageous embodiments are claimed in the subclaims and are explained in particular below.

[0039] According to a further development, the envelope collar projects outward from the shell, essentially "radially" outward from the shell opening, preferably perpendicularly or vertically / orthogonally from the shell radially outward, i.e., away from an interior of the shell intended to accommodate the navigation tracker. Alternatively or additionally, the envelope collar can project outward and form an obtuse angle with the shell, so that it tapers in a funnel shape in a direction pointing into the interior of the shell.

[0040] Preferably, the cover collar extends completely around or around the cover opening, particularly preferably in a rotationally symmetrical shape. The complete, particularly rotationally symmetrical, shape of the collar facilitates handling of the cover when putting it on, as the collar can be gripped equally well at any point.

[0041] In a specific embodiment, the envelope collar can be formed, in particular, as a planar or flat, or as a conical or truncated cone-shaped circular ring. Furthermore, the circular ring can preferably have a circular, oval, or polygonal edge contour radially inward and / or radially outward, although mixed shapes are possible. In general, an inner contour is preferably designed and dimensioned such that it releases the envelope opening either tension-free without an actuating force or under tension upon application of an actuating force, so that the navigation tracker can be accommodated and the cover can be slipped or thrown over (or inserted into) the navigation tracker.

[0042] According to a further development, an adhesive layer, in particular an adhesive layer, can be applied to the enveloping collar, preferably on a top side or an outward-facing side or a side of the enveloping collar facing away from the enveloping opening. In this way, an additional, sterile cover, preferably a sterile patient cover (such as a sterile drape), can be firmly bonded to the adhesive layer and secured. To prevent the adhesive layer from becoming soiled, worn, accidentally stuck together, or contaminated when the sterile cover film is in place, it is preferably prepared covered with a removable protective film, in particular a peel-off protective film.

[0043] The term upper side refers in particular to the side of the collar which is oriented outwards towards the sterile environment or which would come into contact with the outer side of the envelope if the envelope collar were turned over towards the intended sterile outer side.

[0044] To further assist in tightening the cover and to impart greater rigidity to a section of the cover that is intended to be positioned rearward of the navigation markers when put on, the cover of the sterile cover cover in particular has a preferably elastic reinforcement or stiffening section that holds the cover stretched and imprints a defined geometry on it. In this way, the cover can span the navigation markers under (intrinsic) pre-tension when put on, which reduces wrinkles and improves the optical detection of the navigation markers. The reinforcement or stiffening section can also be designed, for example, as is the case with the cover collar, from cardboard, plastic, or sheet metal.

[0045] Creases in the area of ​​the navigation tracker are almost completely eliminated if, according to a further development, the cover has a transparent, dimensionally stable cover section, preferably a viewing panel, which is designed and constructed to allow a view of the navigation markers after being slipped over the navigation tracker. In other words: After being slipped over the cover, the transparent, dimensionally stable cover section spans the navigation markers, eliminating any crease formation in their area, and the optical detection of the navigation markers is optimal and defined.

[0046] In order to be able to maintain a defined position of the transparent, dimensionally stable cover section, it can in particular have, preferably on an inner side, a clip, preferably a jaw clip or a C-clip with at least two elastically deformable clip arms arranged opposite one another. The clip is intended and designed to engage around and behind a corresponding counterpart on the navigation tracker, in particular a knob or head, and thus to lock onto the knob or head (removable again without tools). Of course, the same effect is achieved if the knob or head is provided on the transparent, dimensionally stable cover section, which requires that the corresponding counterpart, i.e. the clip, is provided on the navigation tracker.The first variant (clip on the transparent, dimensionally stable section of the cover) is preferred, as the navigation tracker is a high-quality, high-precision component, preferably made of the highest quality materials—especially stainless steel. A knob or head for this type of component is easier to manufacture than a clip. Conversely, the clip is preferably formed on the transparent, dimensionally stable section of the sterile cover—which is particularly suitable as a disposable item.

[0047] Alternatively or in addition to the fastening by means of the knob or head and the corresponding clip as its counterpart, at least one clip, preferably a jaw clip or a C-clip with at least two elastically deformable clip arms arranged opposite one another, can be provided, in particular glued, on the transparent, dimensionally stable cover section, preferably on an edge of the dimensionally stable cover section, which clip is designed to latch with, or to engage positively or engage behind, a spacer, preferably on the edge, of a support structure of the navigation tracker. According to a further development, the sterile cover cover also has transparent and dimensionally stable caps provided separately from the cover, which are designed such that, after being put on, the respective cap can be attached to the cover and placed on a navigation marker covered there by the cover.In this way, the transparent cap allows the transparent cover to be tightened locally and secured to the respective navigation marker. The first tightening—through the weighted collar—is thus a tightening preparation of the cover to prevent a fold in the cover from being pulled between the navigation marker and the cap when the cap is later put on.

[0048] A further aspect of the present disclosure (which can also be claimed independently) provides, with regard to a navigation tracker according to the present disclosure, that the navigation tracker has a support structure or a rigid body for spatial tracking, on which navigation markers are arranged, which are in particular actively designed as an IR light-emitting diode or passively as an IR reflector body.

[0049] Preferably, the support structure or the rigid body can be designed to be absorbent for a specific wavelength range, particularly for infrared radiation, at least on one side or front side containing the navigation markers, or to have a low reflectance, particularly with respect to this wavelength range. In this way, reflections for this wavelength range are minimized or even eliminated. This is particularly advantageous in the case where (residual) radiation nevertheless passes through the previously described absorbent sleeve section of the sterile cover sleeve. This (residual) radiation is then further absorbed by the support structure.

[0050] The support structure is preferably designed as a polygonal plate, with the number of corners preferably determined by the number of navigation markers. With preferably four navigation markers, this results in a square plate. The corners are preferably rounded in one plan plane of the plate, so that the sterile cover film covering them or placed over them cannot be damaged at the corners.

[0051] According to a further development of the medical navigation tracker, the support structure has a dark color, in particular black, at least on the side having the navigation markers, in particular on the front side. Alternatively or additionally, it is matte (or has a high degree of roughness). The material of the support structure, in particular on the side or front side having the navigation markers, in particular at least superficially, is plastic or a blasted metal. The same attributes with regard to color, matte finish and / or material, or a selection of these attributes, are preferably also exhibited by at least one peripheral edge of the support structure, since it may be in the field of view of the tracking camera that captures the navigation markers. In addition, the rear side of the support structure, which is generally shaded by the front side and edge side, can also exhibit the aforementioned attributes or a selection of these attributes.

[0052] According to a further development, at least one of the navigation markers protrudes from a base of the support structure. This base is provided and designed to latch and / or couple to the at least one transparent sleeve section of the sterile cover sleeve, which is transparent to a specific wavelength range, in particular infrared radiation, in particular via an O-ring or a snap ring with a round cross-section, or to be elastically encompassed by the latter, so that the at least one transparent sleeve section is positioned precisely and / or concentrically to the navigation marker. For this purpose, the base can, for example, have a circumferential collar that forms an undercut for the at least one transparent sleeve section, so that it can be plugged onto the base and latched into place.

[0053] In particular, the absorption rate of the absorbing shell section for the specific wavelength range is greater than 60%, particularly preferably greater than 80%, and most preferably greater than 90% or even 95%, in order to reduce and, in particular, prevent unwanted reflection. In particular, the transmission rate for the transparent shell section for the specific wavelength range is greater than 60%, particularly greater than 80%, to ensure good detection of the navigation markers.

[0054] A further (also independently claimable) aspect of the present disclosure, with regard to a navigation tracker according to the present disclosure, provides that a navigation tracker to be sterilely wrapped has at least one element (a spacer) against which a sterile cover sleeve or slip-on sleeve is tightened and which prevents direct contact of the sleeve with navigation markers of the navigation tracker, in order to prevent, in particular, a "corner" with folds when placed directly on the cover sleeve. If a cover sleeve were placed directly on the navigation markers, which would thereby also form a corner of the cover sleeve, good visibility and thus also precision would be impaired.

[0055] In a specific embodiment, the latter medical navigation tracker has a support structure designed as a cross or a star, or a rigid body designed in this way, wherein a navigation marker is arranged at each end section of the cross or star, which is configured, in particular, actively as an IR light-emitting diode or passively as an IR reflector body. According to the disclosure, a spacer is arranged adjacent to at least one of the navigation markers, preferably adjacent to each of the navigation markers, which spacer extends at least partially in a direction transverse to a plane spanned by the navigation markers.By means of the at least one spacer or in cooperation with the latter, on the one hand, according to the disclosure, a sterile cover sleeve thrown over the navigation tracker, preferably a sterile cover sleeve designed according to the present disclosure, can be held at a distance from the at least one navigation marker, preferably from all navigation markers, and on the other hand, the cover sleeve can be tightened on the at least one spacer.

[0056] The navigation tracker, with its preferably four navigation markers, is fundamentally used for tracking by a navigation system, in particular a tracking system, for example an optical tracking system, in order to determine at least one position of the navigation tracker, preferably also its orientation (i.e., its overall position), in space. In one embodiment, the respective navigation marker can be a trackable light-emitting diode. In another embodiment, the respective navigation marker can be a trackable reflector, in particular a spherical one. The respective embodiment as an infrared (IR) LED or reflector marker is particularly preferred.

[0057] In a preferred development, spacers are arranged on the support structure next to each navigation marker, extending transversely to the plane or surface beyond the respective navigation marker. The respective spacer thus forms a simple rod or mast that can easily hold the cover of a covering cover that is to be thrown or thrown over at a distance. It can also be said that the navigation markers are arranged in an inner area and surrounded by spacers in an outer area (for example, navigation markers within a circle and spacers outside the circle).

[0058] In an alternative or supplementary development, respective spacers extend from the support structure in an extension, in particular radially, outwardly. These spacers are designed in the form of a, in particular C-shaped, stirrup hook. A plane of the stirrup hook is transverse, preferably perpendicular, to the plane spanned by the navigation markers. The respective stirrup hook is preferably designed such that it extends (radially) outwardly, away from the respective navigation marker, and is curved back perpendicular to the plane spanned by the navigation markers with a radius such that it extends back toward the respective navigation marker.

[0059] Preferably, an end portion of the curved back hook remains spaced from the navigation marker. In other words, the end portion of the curved back hook does not extend to the navigation marker, in particular not beyond it, so that the view of the navigation marker is not obstructed by the hook.

[0060] Particularly preferably, an end tangent of the end section of the recurved stirrup hook is spaced from the navigation marker. In other words, an imaginary tangential extension of the end section of the recurved stirrup hook, i.e., the end tangent, passes the navigation marker at a distance of, in particular, 1 to 5 mm, preferably 1 to 3 mm.

[0061] The convex (radially) outward-facing hooks allow for easy fitting, especially without snagging or damaging the navigation tracker on the cover opening.

[0062] Both spacer designs, the bracket hooks as well as the simple rods or masts, protect the navigation tracker, especially its sensitive structural elements for detection, such as the navigation markers, from damage, particularly from impact and thus from displacement of the navigation markers. This allows the navigation tracker to continue to be used even after a fall to the ground without any loss of accuracy. Furthermore, these preferably define or essentially predetermine the contour of the cover.

[0063] According to a particularly preferred development, the navigation tracker has at least one central spacer on the support structure, centered on the navigation markers, which extends beyond the navigation markers transversely to the plane or surface spanned by the navigation markers. In cooperation with the at least one (radially) outwardly arranged spacer, preferably with all four (radially) outwardly arranged spacers, the central spacer serves to centrally support the sterile cover sleeve at a level above the navigation markers and thus fulfills the purpose of keeping the sterile cover sleeve securely spaced from the navigation markers (similar to a central tent pole). In a configuration with the four bracket hooks, the central spacer enables a pyramidal shape or support of the sleeve of the sterile cover sleeve above the navigation markers or at a distance from the navigation markers.

[0064] According to a further development, the central spacer is designed in the form of a knob or head in order to be encompassed and engaged behind by a clip of the sterile cover, whereby the sterile cover can be fixed to the navigation tracker by locking it.

[0065] Preferably, the navigation tracker has a fastening interface which is provided and designed for attachment to and fastening on a tracker arm, in particular on a patient tracker arm.

[0066] The mounting interface is preferably formed by a circular-cylindrical mounting mandrel or pin, from which an angled, preferably ergonomically shaped, handle extends. A central section of the support structure, preferably an intersection section of support arms on which the navigation markers are mounted, is attached at a predetermined, rigid angle to the upper end section of the handle.

[0067] Preferably, the navigation tracker is formed in one piece from the handle to the support structure and up to the receptacles for the navigation markers.

[0068] The navigation tracker is preferably made of stainless steel for reasons of stability and for reasons of its processing - i.e. its cleaning and disinfection.

[0069] A sterile cover system according to the present disclosure combines a navigation tracker configured according to at least one aspect of the present disclosure with a sterile cover sleeve configured according to at least one aspect of the present disclosure, whereby the already mentioned advantages of the two components naturally also come into effect, so that a repeated mention of the effects and advantages is omitted in order not to overload the document. According to a preferred development, the navigation tracker is covered by the sterile cover sleeve or the sterile cover sleeve is placed over the navigation tracker, so that the, in particular non-sterile, navigation tracker can be used in a sterile environment.

[0070] According to a further development of the sterile cover system, the navigation markers are each accommodated in one of the casing sections that are transparent for the wavelength range, in particular for IR radiation, and are covered or enclosed by these transparent casing sections in a transparent and sterile manner for the wavelength.

[0071] According to a further development of the sterile covering system, the bases of the support structure from which the navigation markers each protrude are each elastically encompassed by one of the sheath sections that are transparent to the wavelength range, in particular to IR radiation, so that these transparent sheath sections are reinforced and / or coupled to the support structure, whereby the transparent sheath sections are arranged in a precisely positioned and / or concentric manner to the navigation markers.

[0072] According to an alternative development of the sterile cover system, the sterile cover sleeve is designed in the variant with an envelope collar and is thrown over the navigation tracker, so that the navigation tracker is accommodated in the sterile cover sleeve, and the sleeve of the sterile cover sleeve is tightened by means of the weight of the envelope collar of the sterile cover sleeve and by means of gravity, wherein the spacers of the navigation tracker hold the sterile cover sleeve, in particular its transparent sleeve, at a sufficient distance - preferably a minimum of 1 mm and / or a maximum of 3 mm - from the navigation markers.

[0073] According to a preferred alternative of the sterile cover system, the cover of the sterile cover formed with an envelope collar is held pyramidally at a distance from the navigation markers by the (radially) outer spacers and the central spacer.

[0074] According to another preferred alternative of the sterile cover system, the cover of the sterile cover formed with an envelope collar is held at a distance from the navigation markers in a planar manner by the spacers arranged next to the navigation markers, and in particular by the central spacer.

[0075] According to a further development of the sterile cover system, the navigation tracker has the knob or head, and the sterile cover sleeve has the transparent, dimensionally stable sleeve section with the clip, preferably a jaw clip or C-clip with at least two oppositely arranged, elastically deformable clip arms. The clip encompasses and engages behind the knob or head, so that the clip is locked to the knob or head, and the transparent, dimensionally stable sleeve section of the sterile cover sleeve is secured to the navigation tracker.

[0076] According to a preferred development of the sterile cover system, the transparent, dimensionally stable cover section is supported on the (radially) outwardly arranged spacers, in particular the hanger hooks.

[0077] All disclosures regarding the sterile drape sheath according to the present disclosure, as well as regarding the navigation tracker according to the present disclosure, also apply to the drape system of the present disclosure, and vice versa.

[0078] Short description of the characters

[0079] The present disclosure will be explained in more detail below using preferred embodiments with reference to the accompanying figures. Figure 1 shows a perspective view of a sterile cover sheath according to a first embodiment, which encloses a conventional patient navigation tracker;

[0080] Fig. 2 is a perspective view of the sterile cover sheath according to Figure 1 with the encased patient navigation tracker, wherein a sterile drape is arranged on the cover sheath, by which a patient is covered;

[0081] Fig. 3 is a perspective (front) view of a sterile draping system with a sterile draping cover according to the disclosure and a navigation tracker according to the disclosure, according to a preferred first embodiment;

[0082] Fig. 4 is a perspective (side) view of the sterile draping system according to Figure 3;

[0083] Fig. 5 is a perspective (front) view of a sterile cover sheath according to a second embodiment;

[0084] Fig. 6 is a perspective view of a sterile cover system comprising a sterile cover sheath according to the disclosure and a navigation tracker according to the disclosure, according to a second embodiment;

[0085] Fig. 7 is a perspective (front) view of the sterile cover sheath of the sterile cover system according to Fig. 6 with an additional drape;

[0086] Fig. 8 is a perspective (front) view of the sterile cover according to Figure 7 with an adhesive strip arranged on the additional drape;

[0087] Fig. 9 is a perspective (side) view of a navigation tracker according to the first embodiment shown in Figures 3, 4, and 6; Fig. 10 is a (side) longitudinal sectional view through a sterile cover system comprising a disclosed sterile cover sleeve and a disclosed navigation tracker according to a third embodiment;

[0088] Fig. 11 is a side view of a sterile cover system comprising a sterile cover sleeve according to the disclosure and a navigation tracker according to the disclosure, according to a fourth embodiment;

[0089] Fig. 12 is a perspective (front) view of a sterile cover sheath according to a third embodiment, enclosing a patient navigation tracker;

[0090] Fig. 13 is a perspective front view of a navigation tracker according to another embodiment;

[0091] Fig. 14a is a perspective front view of a navigation tracker according to another embodiment with navigation markers enclosed in transparent cover sections in cap form;

[0092] Fig. 14b shows a sterile cover system with the navigation tracker according to Figure 14a, covered by a sterile cover sleeve which has an opaque drape and the transparent sleeve sections in cap form according to Figure 14a;

[0093] Fig. 14c shows an image of the sterile draping system according to Fig. 14b in an image from an IR tracking camera;

[0094] Fig. 15a is a perspective front view of a navigation tracker according to another embodiment with a plate-shaped support structure and with navigation markers projecting from bases;

[0095] Fig. 15b shows an image of the navigation tracker according to Fig. 15a in an image from an IR tracking camera; Fig. 16a shows the sterile cover according to Fig. 14b with the drape fully unfolded in a perspective front view;

[0096] Fig. 16b the sterile cover sleeve according to Figure 16a in the area of ​​the transparent sleeve sections in cap form;

[0097] Fig. 16c the sterile cover sleeve according to Figures 16a and 16b in a perspective rear view, in the area of ​​one of the transparent sleeve sections in cap form;

[0098] Fig. 17a shows the sterile draping system according to Figure 14b in a front view, with the navigation tracker fully covered, extended by a patient drape;

[0099] Fig. 17b shows an image of the sterile draping system according to Fig. 17a in an image from an IR tracking camera;

[0100] Fig. 18a shows a sterile cover system according to a further embodiment in a perspective front view with a navigation tracker according to Fig. 15a, over which a sterile cover sheath according to Fig. 3 is thrown;

[0101] Fig. 18b shows an image of the sterile cover system according to Fig. 18a in an image from a tracking camera;

[0102] Fig. 19a shows a sterile cover system in a front view according to a further embodiment with a navigation tracker according to Fig. 15a, which is covered by a sterile cover sheath with a transparent plate;

[0103] Fig. 19b shows an image of the sterile cover system according to Fig. 19a in an image from a tracking camera; Fig. 20a shows a sterile cover system in a perspective front view according to another embodiment with a navigation tracker according to Fig. 15a, which is covered by a sterile cover sleeve with a transparent plate; and

[0104] Fig. 20b to 20d show an image of the sterile cover system according to Fig. 20a, each in an image from a tracking camera, wherein the plate has an increasing thickness from Fig. 20b to Fig. 20d.

[0105] Fig. 21 a perspective design of a support structure of the navigation tracker.

[0106] The figures are schematic in nature and are intended only to assist in understanding the invention. The features of the various embodiments may be interchangeable.

[0107] Detailed description of preferred embodiments

[0108] According to the disclosure, the following describes how a non-sterile navigation tracker, in particular a patient tracker, is covered using a sterile, transparent cover according to the disclosure, without having to accept excessive losses in tracking accuracy. Furthermore, it is described that the cover according to the disclosure serves as a support, connection, or seal for a sterile patient cover. It is further described that the navigation tracker according to the disclosure contributes to maintaining tracking accuracy after the cover is put on. An ergonomic design, according to the disclosure, of both the cover and the navigation tracker, facilitates their handling and their interaction as a sterile cover system according to the disclosure.

[0109] Figure 1 shows a sterile cover sleeve 1 according to a first exemplary embodiment, which encloses a conventional navigation tracker 2. The navigation tracker 2 is sufficiently rigidly attached to a patient P, more precisely to their head, via a clamp and a patient tracker arm. The cover sleeve 1 has a transparent cover 4 that encloses the navigation tracker 2. The cover sleeve 1 has an opening 8 on its underside, which is completely delimited and surrounded by a collar 6. The collar protrudes radially outward, essentially perpendicular to the cover 4.

[0110] In the exemplary embodiment, the cover collar 6 is made of cardboard (it can alternatively be made of plastic or metal) and, due to its comparatively higher rigidity, keeps the comparatively flexible, less inherently rigid cover 4 open, so that the cover opening 8 remains reliably open at all times. This fundamentally enables ergonomic and easy insertion of the navigation tracker 2 into the cover opening 8 and thus the slipping of the cover 1 over the navigation tracker 2.

[0111] After being thrown over, i.e., in the state shown in Figure 1, the cover 1 sags against the navigation tracker 2 due to the effect of gravity. As disclosed, the cover collar 6 has a comparatively high weight for this purpose and thus acts as a weight, by which the cover 1 is pulled down along the navigation tracker 2, essentially automatically, i.e., without the need for further manual handling by personnel. It proves advantageous that the cover collar 6 keeps the cover opening 8 permanently open. At the end of the sagging, the upper edge 16 of the cover 4 comes into contact with the navigation tracker 2, and the cover 1 has reached its final vertical position, which is shown in Figure 1.

[0112] Due to the weighting that the envelope collar 6 represents for the cover 4, the cover 4 is subsequently tightened by gravity, i.e., again in principle automatically, as disclosed. The cover 4 is made of a sufficiently flexible material, and thus only a few residual folds remain in the cover 4 - if any at all - so that the detection quality of navigation markers of the navigation tracker 2 (see in particular Figures 3 and 4) by a tracking system is high. The detection of the navigation tracker 2 occurs in a known manner, for example by an infrared camera (not shown). For this purpose, infrared radiation is emitted from a radiation source, for example, which is reflected by the navigation markers (spherical) of the navigation tracker 2, designed as IR reflector markers, and detected by the infrared camera.The evaluation of this recording by the tracking system or a navigation system results in a position of the navigation tracker 2 with reference to the coordinate system of the infrared camera of the tracking system.

[0113] Using a pointer also equipped with a navigation tracker, prominent points on patient P can be scanned. By mapping these prominent, scanned points with their representations in preoperatively acquired images of patient P—for example, a CT or MRI scan—patient P is then registered with respect to the preoperative images.

[0114] According to Figure 2, the patient P is sterilely covered by means of a sterile patient cover 18, which, as disclosed, rests on the envelope collar 6.

[0115] Figure 3 shows a first embodiment of a sterile covering system 20 according to the disclosure, comprising a sterile covering sleeve 1 according to the disclosure and a navigation tracker 2 according to the disclosure (instead of a conventional one), in a perspective view from the front. The navigation tracker 2 has a cross-shaped support structure 24 made of stainless steel, with a spherical navigation marker 22 designed as an IR reflector marker arranged on each free end section of the crossbeams of the support structure 24.

[0116] In contrast to the conventional navigation tracker 2 according to Figures 1 and 2, on the navigation tracker 2 according to Figure 3, a bow-shaped spacer 26 extends in a plane of the support structure 24 and projects radially outward beyond the respective navigation marker 22, by means of which the cover 4 is held at a distance from the navigation markers 22. Furthermore, the navigation tracker 2 according to Figure 3 has, according to the disclosure, a knob-shaped spacer 28 centrally between the navigation markers 22, which, in cooperation with the bow-shaped spacers 26 arranged radially outward, holds the transparent cover 4 at a distance from the navigation markers 22.The disclosed envelope collar 6 of the cover system 20, which acts as a weight, ensures that the cover 4 is always pulled taut on the navigation tracker 2, while the disclosed spacers 26, 28 ensure that the cover 4 always remains spaced apart from the navigation markers 22, preferably at a distance of 1 to 3 mm.

[0117] According to Figures 3 and 4, the disclosed cover 4 additionally has a stiffening section 30, which is arranged rearwardly on one side of the cover 4 and thus spreads the cover 4 into a predefined shape. This simplifies the wrapping process, as the risk of the navigation tracker 2 becoming jammed or caught in the cover 4 is minimized. Furthermore, in its final position, the navigation tracker 2, in cooperation with the stiffening section 30, prestresses the cover 4, so that the drape of the cover 4 over the navigation markers 22 is reduced to zero.

[0118] In other words, the stiffening section 30 reduces the rearward flexibility of the shell 4, so that the shell 4 is tensioned or tightened on the front side - that is, in a region of the navigation markers 22 - onto the spacers 26, 28 with a rearwardly acting tensioning force of the stiffening section 30.

[0119] The effect is particularly evident in the side view of the sterile cover system 20 shown in Figure 4.

[0120] Figure 5 shows the sterile cover sheath 1 of the sterile cover system according to Figures 3 and 4 in a perspective view from the front and without navigation tracker.

[0121] Regardless of the embodiment, the sleeve 4 of the sterile cover sleeve 1 is preferably conically tapered and in particular welded at a closed end section, in particular towards an edge 16 which forms a stop for the navigation tracker 2 in the sterile cover sleeve 1.

[0122] The tapered shape ensures that the navigation tracker 2 can no longer be accidentally displaced in its final position within the sterile cover sheath 1. This prevents a change in the accuracy of the detection of the navigation markers 22 during the operation, for example, if an accidental impact occurs against the sterile cover sheath 1.

[0123] For a better understanding of the function of the spacers 26, 28 of the navigation tracker 2, reference is made to Figure 9, which shows the navigation tracker 2 according to Figures 3, 4, and 6 without the cover and in a side view. The outer spacers 26 are each formed by a convex, outward-facing, C-shaped wire.

[0124] The spacers 26 initially extend radially outward in a straight line, extending a respective beam end of the support structure 24, beyond the navigation marker 22 located there and are C-shaped, bent back transversely to a plane of the support structure 24 in the direction of the navigation marker. End tangents 32 of the bent back spacers 26 sweep over the navigation marker 22 at a preferred distance of a few millimeters and point toward an apex of the central spacer 28. This spacer projects beyond the navigation marker 22, and the end tangents converge at its apex.In this way, when the sterile cover sleeve 1 is thrown over the navigation tracker 2, the spacers 26 and 28 create a kind of tent effect - in the sense of a pyramid tent - whereby the central spacer 28 then functions as a central "tent pole" and its apex functions as a flat guide cap so that the sleeve 4 can tighten evenly against it.

[0125] The curved spacers 26 act as a type of collision protection because they shield the navigation markers 22 at least partially from the outside, both with regard to the process of putting them on - here they prevent the cover 4 or the cover collar from snagging on the navigation markers 22 - and if, for example, the navigation tracker 2 is accidentally dropped - here they prevent the direct impact or impact of the navigation markers 22, which affects the maintenance of its precision and its service life.

[0126] According to Figure 9, the navigation tracker 2 has a mounting interface 34 for connection to a tracker arm, which is formed by a circular-cylindrical mounting mandrel or pin. Extending from this is an angled, ergonomically shaped handle 38, to whose upper end section, as shown in Figure 9, a central or middle section 40 of the support structure 24 is attached, which also supports the central spacer 28. An angle between a mounting axis 42 of the mounting interface 34 and a plane of the support structure 24, and thus a plane of the navigation markers 22, is rigidly defined via the angled handle 38 and its transition to the middle section 40. The navigation tracker 22 thus has an ergonomic design, by means of which it can be coupled to an adapter, for example, the tracker arm, in a manner that is simple for an operator because it is vertical, while simultaneously being aligned with the camera of the tracking system.

[0127] Preferably, the navigation tracker 2 is formed in one piece, from the handle 38, through the support structure 24, to the receptacles for the navigation markers 22. For example, it is possible to manufacture the aforementioned section of the navigation tracker 2 in one piece by milling or additive manufacturing. Alternatively, the navigation tracker 2 can also be designed in multiple parts, with the components being assembled or joined together to form a single unit. For example, the support structure 24 can be manufactured separately from the reflector markers 22 and later connected to one another, for example, by screwing them in using a thread, pressing them into a bore, or joining them together by means of a material bond.

[0128] Preferably, the Navigation Tracker 2 is made of stainless steel for reasons of stability and for reasons of its processing - especially its repeated cleaning and disinfection.

[0129] It should be noted that the shape of the enveloping collar is, of course, not limited to the circular ring shown in the exemplary embodiments. The same applies, of course, to the angle formed by the enveloping collar with the sheath, which is approximately 90° in the exemplary embodiments shown. The shape and angle of the enveloping collar can be configured, in particular, depending on the application of the sterile covering sheath, in particular depending on the position of the navigation tracker to be encased during the operation.

[0130] Basically, the cover collar advantageously has an inner contour that is oriented towards the intended navigation tracker to be covered, so that the latter can be inserted into the cover sleeve without hitting it and the sterile cover sleeve is not damaged.

[0131] It is also advantageous if the cover collar is made of a flexible material that can be bonded together. This allows for a good connection to the cover of the sterile cover sleeve, so that the seal between the sleeve and the cover collar, which is important for the sterile covering of the non-sterile navigation tracker, can be easily achieved, for example, by gluing or welding.

[0132] Figure 6 essentially shows the sterile cover system 20 according to Figures 3 and 4, wherein an additional adhesive layer 44, preferably an adhesive layer, is provided on the upper side of the envelope collar 6, which is covered with a removable protective film 46, preferably a peel-off protective film. If the protective film 46 is removed, the adhesive layer 44 is exposed and, according to Figure 7, a supplementary or larger drape 48 can be firmly attached to it, thereby spatially expanding a sterile barrier around the navigation tracker 2 and better preventing cross-contamination. In the illustration according to Figure 7, this extension is shown with drape 48, although for reasons of clarity, a navigation tracker accommodated in the sterile cover sleeve 1 has been omitted.

[0133] Starting with the expanded sterile cover 1 shown in Figure 7, Figure 8 shows, in a highly schematic manner, a further possible expansion of the sterile barrier formed by the sterile cover 1 around the navigation tracker 2, by supplementing the cover sheet 48 with an additional adhesive layer 44 with a removable protective film 46. An even larger sterile cover sheet can be firmly attached to this to further prevent cross-contamination.

[0134] Figure 10 shows a further embodiment of a sterile covering system 20 with a variant of a sterile covering sleeve 1 and a navigation tracker 2 according to the disclosure, in a sectional side view. The sterile covering sleeve 1 according to Figure 10 in this case has a sleeve 4 that has a transparent, dimensionally stable sleeve section 4'. In contrast to the rest of the sleeve 4, this sleeve section 4' is therefore stiffer and can also be referred to as a disc. According to one possible embodiment, the dimensionally stable sleeve section 4' nevertheless has a certain flexibility, with which it is tightened by the gravitational effect of the sleeve collar (6, see Figures 1, 3, 4) at the outer spacers 26 and at the central spacer 28. However, due to its dimension stability, its tendency to wrinkle is fundamentally greatly reduced.

[0135] In a further embodiment, a clip 50 is provided centrally on an inner side of the sleeve section 4' according to Figure 10. This clip is designed in the style of a C-clip with clip arms 52 that engage behind and surround a head of the knob 28. In this way, the sterile cover sleeve 1 and the navigation tracker 2 are locked together, ensuring that the dimensionally stable sleeve section 4' reliably allows a high-quality view of the navigation markers 22 and does not slip.

[0136] According to a not-shown alternative embodiment to the embodiment according to Figure 10, an edge of the dimensionally stable casing section 4' can have at least one clip, in particular a plurality of clips, which are, for example, firmly attached to the edge of the dimensionally stable casing section 4', in particular glued (to / on), wherein the clip(s) are each clipped onto one of the outer spacers 26 or can engage behind it. In this way, for example, the central clip 50 in Figure 10 can be dispensed with, and the dimensionally stable casing section 4' is secured not at the central head or knob 28, but at the edge on the outer spacers 26.Alternatively, a central clip 50 can be used together with at least one edge-side clip, preferably several clips (in particular one clip per spacer), in order to ensure a stable fixation of the dimensionally stable sleeve section 4' of the sterile cover sleeve 1.

[0137] Figure 11 shows, as an alternative to the previously disclosed navigation trackers 2 and sterile cover systems 20, an embodiment of a navigation tracker 2 having spacers 27 that protrude normally from the support structure 24 next to the navigation markers 22 and extend beyond the navigation markers 22. Thus, the cover 4 is supported by them in a distributed manner over the surface of the support structure 24, pointwise.

[0138] Figure 12 shows, as an alternative to the previously disclosed sterile cover sleeves 1, an embodiment of a sterile cover sleeve 1 that forcibly tightens the sleeve 4 at the navigation markers 22. Separate, transparent caps 54 are provided for this purpose, in the same number as the navigation tracker 2 has navigation markers 22. After the sterile cover sleeve 1 has been thrown over the navigation tracker 2, when the sterile cover sleeve 1 is tightened by the sleeve collar as disclosed, these caps are attached to the sleeve 4 above the respective navigation marker and slipped over it. In this case, the sleeve 4 undergoes forced or enforced tightening at the navigation markers 22, in addition to the previous tightening due to gravity, in that the respective cap 54 pulls the sleeve 4 over the navigation marker 22.

[0139] Figure 13 shows a further embodiment of a navigation tracker 2 in a perspective side view. The navigation tracker 2 according to Figure 13 has a preferably centrally arranged screw head 28, through which the support structure 24 can be attached in an axially secured manner. In this embodiment, a threaded engagement is provided between the screw head 28 and the support structure 24 (internal thread-external thread).

[0140] In this embodiment, the screw head 28 has a cylindrical disk shape with radially outer knurling or a grooved (radially) outer peripheral structure to enable manual gripping and handling. The outer peripheral knurling is also suitable for forming a gripping portion of the screw head 28, by means of which the navigation tracker 2 can be securely gripped and aligned manually or mechanically—particularly for mounting or dismounting on an adapter arm.

[0141] Preferably, the transparent caps are centered on the bases of the navigation markers and, when attached, hit the surface of the wings so that they are clearly positioned.

[0142] The navigation tracker 2 according to the disclosure shown in Figure 13, in particular its cross-shaped support structure 24, is made of stainless steel. To prevent reflections on the support structure 24 and thus not interfere with the detection of the reflector markers 22, a surface of the support structure 24 is preferably corundum-blasted.

[0143] The cross-shaped support structure 24 according to Figure 13 has two crossed beams, at the end sections 56 of which one of the navigation markers 22 is arranged, protruding beyond the plane of the support structure 24. The end sections 56 have an approximately circular, convex outline in the plane of the support structure 24, with the reflector markers 22 arranged concentrically to the outline. In this case, a radius of the circularly convex outline of the end sections 56 is larger than a radius of the reflector markers 22, so that the end sections 56 in the plane of the support structure 24 - and thus at a base of the reflector markers 22 - form a radially outwardly projecting, circumferential arc, via which the cover of the sterile cover cover can be kept at a distance from the reflector markers 22 in the radial direction, which can prevent or at least reduce creasing of the cover as well as possible damage to the cover 4 at the respective reflector marker 22.

[0144] As already discussed in the exemplary embodiment according to Figure 12, in the embodiment of the navigation marker 2 according to Figure 13, the drape of wrinkles can be minimized and the attachment of the sheath to the respective reflector marker 22 can be improved if the navigation markers 22 are each covered by a separate, transparent cap after the sterile cover sheath has been placed over the navigation tracker 2. Thus, in addition to the tightening due to gravity, the sheath at the navigation markers 22 undergoes forced tightening by the respective cap pulling and tensioning the sheath over the navigation marker 22.

[0145] Furthermore, the wrinkles are no longer an issue once a transparent cap is placed on the bases of the navigation markers and the drape is non-reflective.

[0146] The caps 54 are preferably deep-drawn or injection-molded, transparent plastic sleeves.

[0147] Figure 14a shows a perspective front view of a navigation tracker 102 according to another embodiment. The navigation tracker 102 has a support structure 124 made of stainless steel with two crossed beams, at the outer end sections of which a navigation marker 22 is arranged and projects perpendicular to the plane of the support structure 124. The navigation markers 22 are spherical in shape so that they can be detected with equal quality from different viewing directions and are supported by a neck which, as shown in Figure 14a, projects concentrically from a circular base 160 of the support structure 124 and perpendicular to the plane of the support structure 124. One can also say that a navigation marker has a spherical head supported by a cylindrical neck.

[0148] To minimize – or even eliminate – reflections on the support structure 124, the front side, a peripheral edge side, and the rear side of the support structure 124 are black in the illustrated embodiment, and the surface is matte. All of these sides are absorbent with respect to the wavelength range detected by the tracking camera – in the illustrated embodiment, this is IR radiation, as already mentioned. Generally, the sides are preparatory to corundum blasting during production to enhance the matte effect through the resulting surface quality.

[0149] According to Figure 14a, the navigation markers 22 or IR reflector markers 22 are each covered by and enclosed in a separate, transparent, cap-shaped casing section 154. A transparent property of the casing sections 154 relates to the wavelength range detected by the tracking camera – in the embodiment shown, this is the IR radiation. The transparent, cap-shaped casing sections 154 are injection-molded (or alternatively, deep-drawn) transparent plastic sleeves or plastic caps. The material is preferably PC, PS, or PMMA. The material can also be PETG (polyethylene terephthalate glycol), which is a highly transparent, easy-to-process, and inexpensive plastic. The support structure 124 according to Figure 14a is attached at its rear to a patient tracker arm, which in turn can be attached to a patient in a known manner.

[0150] Figure 14b shows a further embodiment of a sterile cover system 120 with the navigation tracker according to Figure 14a, which is covered by a sterile cover sleeve 101 according to a further embodiment.

[0151] This sterile cover sleeve 101 has an absorbent sleeve section 158 designed as a drape. The absorbent property of the sleeve section 158 relates to the wavelength range detected by the tracking camera – in the illustrated embodiment, this is IR radiation, as already mentioned several times. The drape 158 thus neither transmits nor reflects IR radiation. It should be noted that 100% absorption is not absolutely necessary; rather, for sufficiently precise detection of the IR reflector markers 22, a sufficiently high absorption of the IR radiation, possibly less than 100%, is entirely sufficient.

[0152] According to the disclosure, the IR navigation or reflector markers 22 are thus enclosed / covered by the transparent cover sections 154 in a transparent and thus detectable manner in the IR wavelength range, whereas the remaining area of ​​the navigation tracker 102, which does not need to be detected by the tracking camera and should not be detected if possible, is covered by the IR-absorbing cover section 158. The absorbing property of the cover section 158 means that the cover section 158 does not have any IR reflections that would interfere with the detection of the IR navigation or reflector markers 22. The sterile cover cover 101 according to the disclosure and the sterile cover system 120 according to the disclosure thus enable precise, reflection-free tracking.

[0153] This freedom from reflection, or at least the lack of reflection, is clearly illustrated in Figure 14c, which shows an image 120' of the sterile draping system according to Figure 14b in an image from an IR tracking camera. Although rudimentary images 158' of the edges and folds of the drape cloth 158 are still recognizable, these are so faint that, in contrast, the images 22' of the IR navigation or reflector markers 22 are sharply outlined and precisely captured, particularly because, due to the absorbing properties of the drape cloth 158, no disturbing reflections occurred and were therefore not captured.

[0154] Figure 15a shows a perspective front view of a navigation tracker 102 according to another embodiment, which, in contrast to the embodiment according to Figure 14a, has a plate-shaped support structure 124. Here, too, the navigation markers 22 projecting from the bases 160 are provided. The support structure 124 according to Figure 15a has the basic shape of a quadrilateral, with one of the navigation markers 22, or IR reflector markers 22, arranged in each of the corners. The support structure 124 according to Figure 15a, like the one according to Figure 14a, is also IR-absorbing on its front, edge, and rear sides.

[0155] Accordingly, in Figure 15b, which shows an image of the front side of the navigation tracker 102 according to Figure 15a in an image from an IR tracking camera, no reflections can be seen and only the images 22' of the IR navigation or reflector markers 22 are sharply outlined and precisely captured.

[0156] Figure 16a shows the sterile cover sheath 101 according to Figure 14b with the fully unfolded, absorbent drape cloth as the absorbent sheath section 158 and the four transparent sheath sections 154 in cap form, in a perspective front view.

[0157] Figure 16b shows the sterile cover sleeve 101 according to Figure 16a in the area of ​​the transparent sleeve sections 154 in cap form. These sections are inserted through a respective recess 162 in the drape sheet 158, starting from its underside, which will later face the navigation tracker to be covered. According to the disclosure, the respective recess 162 is designed as a cross-cut, which is either prefabricated in the drape sheet 158 ​​in the case of a known, standardized navigation tracker, or can be individually and easily inserted into the drape sheet 158 ​​by operating personnel on site.

[0158] Figure 16c shows the sterile cover sleeve 101 according to Figures 16a and 16b in a perspective view from the rear, in the region of one of the transparent, cap-shaped sleeve sections 154. Thus, a rear side of the sterile cover sleeve 101 facing the navigation tracker is visible. According to Figure 16c, the transparent sleeve sections 154 each have a circumferential collar or edge 164, which at the end, pointing toward the navigation tracker (not shown) to be covered, defines an opening 166 through which the navigation markers (not shown) can be inserted into the cap-shaped sleeve sections 154.

[0159] At their ends, in the area of ​​their openings 166, the cap-shaped shell sections 154 are elastically configured and adapted to a width or dimension of the bases 160 such that, after being plugged onto them, they elastically encompass the bases 160. Thus, they are circumferentially clamped onto the bases 160 and thus secured to the support structure 124.

[0160] The collar or edge 164 functions, in particular, as a stop at the plane of the support structure below the base 160. The cap-shaped casing sections 154 are spaced from the collar or edge 164 with respect to their front-end domes 168 (see also Figure 16b) such that when the casing sections 154 are attached until they abut the plane of the support structure, the spherical IR navigation or reflector markers are concentrically enclosed in the domes 168. Thus, they can be captured by the tracking camera from all relevant viewing angles with equal quality and without disruptive refraction or distortion.

[0161] Figure 17a shows the sterile draping system 120 with the sterile cover sleeve 101 according to Figure 14b, the latter completely covering the navigation tracker so that its support structure is no longer visible. The sterile draping system 120 is extended by a patient drape 170, which has a cross-cut through which the navigation tracker covered by the sterile cover sleeve 101 is inserted. As can be seen there, the sterile patient drape 170 overlaps the sterile cover sleeve 101 and thereby simultaneously seals it. If necessary, the intersection of the cross-cut in the patient drape 170 can also be additionally taped with sterile adhesive tape.

[0162] Figure 17b shows a section of an image 120' of the sterile draping system 120 according to Figure 17a in an image from an IR tracking camera. Here, too, the disclosed effect of the absorbent cover section 158 together with the transparent cover sections 154 (see Figure 17a) is clearly visible. The images 22' of the IR navigation or reflector markers 22 therefore exhibit no disturbing reflections and are captured and imaged with sharp outlines.

[0163] To illustrate the potential influence of the reflectivity of a sterile drape system's cover on the precise detection of navigation markers, Figures 18 to 20 below show several "worst-case scenarios" with extreme illumination and / or unfavorable illumination angles of sterile drape systems. The examples shown in Figures 18 to 20 all feature a reflective cover with respect to the detected wavelength range, which can complicate or even prevent patient tracking and navigation.

[0164] In the case of a slack-shaped shell, which, as shown in Figures 18, only spans the navigation markers and does not cover them with tight-fitting cover caps (cf. Fig. 18a), reflections 23' may occur at folds 23 of the shell under extreme illumination (cf. Fig. 18b) and the images 22' of the navigation markers may also have inconsistent, non-reproducible and distorted edge contours due to the undefined shape of the shell and the resulting undefined reflection (cf. also 22', Fig. 18b). Even with a planar and solid shell according to Figures 19, which covers the entire navigation tracker in the sense of a disc (cf. Fig. 19a), undesired reflections 23' may arise between the actual images 22' of the navigation markers under extreme illumination and / or unfavorable angles (cf. Fig. 19b) and the images 22' of the navigation markers may also have inconsistent, non-reproducible and distorted edge contours (cf. also 22', Fig. 19b).

[0165] The intensity of the reflections 23' and the distortion of the edge contours 22' for reflective, planar, and rigid shells according to Figures 20a to 20d depends on both the shell thickness and the shell orientation. According to the figures, the thickness varies between 2 and 0.75 mm.

[0166] Figure 20a shows a sterile cover system with the navigation markers 22, which is not irradiated, as the starting position.

[0167] Figure 20b shows the image of the sterile draping system according to Figure 20a with comparatively low intensity illumination and therefore without reflections or distortion of the edge contours, in an image of the tracking camera.

[0168] Figure 20c shows the image of the sterile draping system according to Figure 20a under a first illumination angle with intense illumination in an image of the tracking camera.

[0169] Figure 20d shows the image of the sterile draping system according to Figure 20a with the same intensity of illumination as in the case of Figure 20c, but with a slightly varied illumination angle.

[0170] Figures 20a to 20d clearly show that, in strong lighting conditions, even small changes in the illumination angle can lead to an increase in reflections 23' and distortions of the edge contours 22*, and thus to incorrect tracking or tracking errors that are difficult to compensate for. Figure 21 shows a further exemplary embodiment of a navigation tracker 2 according to the disclosure in a perspective view obliquely from the front. The navigation tracker 2 has the support structure 24. In this embodiment, the support structure 24 has a wing-shaped base plate with two wings 60. A first wing of the two wings 60 is larger than a second wing of the two wings 60. The two wings 60 are formed by a central cross, with two free ends of the cross being connected to one another.

[0171] At each free end of the cross, a base 62 is attached, which essentially corresponds to the described base 160. The base 62 has a circular cross-section and protrudes perpendicularly from the base plate. Preferably, the base 62 can be rotationally symmetrical.

[0172] The base 62 has a substantially disc-shaped base body 64 and a central pin 66 protruding outward from the base body 64 for receiving a navigation marker 22. The pin 66 has a circumferential radial groove 68 for axially securing the navigation marker 22. The navigation marker 22 can be plugged onto the pin 68 and positioned concentrically. The base body 64 has a circumferential radial groove 70. An O-ring or a (round) snap ring can be received in the radial groove 70 in order to attach the transparent, dimensionally stable sleeve section 154. The base body 64 has a radial notch 72 which extends axially to an end face of the base body 64 and to the radial groove 70.

[0173] List of reference symbols

[0174] 1 ; 101 sterile cover

[0175] 2; 102 navigation trackers

[0176] 4 Cover

[0177] 4' dimensionally stable hull section

[0178] 6 shawl collar

[0179] 8 Envelope opening

[0180] 16 edges

[0181] 18 Patient coverage

[0182] 20; 120 sterile drape system

[0183] 22 navigation markers

[0184] 22' IR image navigation marker

[0185] 23' IR reflection

[0186] 24; 124 supporting structure

[0187] 26 spacers

[0188] 27 spacers

[0189] 28 screw head

[0190] 30 reinforcement section

[0191] 32 End tangent

[0192] 34 Mounting interface

[0193] 38 handle

[0194] 40 middle section

[0195] 42 Mounting axis

[0196] 44 Adhesive layer

[0197] 46 protective film

[0198] 48 sterile cover

[0199] 50 clips

[0200] 52 Clip Arm

[0201] 54 cap

[0202] 56 final section

[0203] 60 wings

[0204] 62 Socket 4 Base 6 Pin 8 Radial groove 0 Radial groove 2 Notch

[0205] 154 transparent cover section

[0206] 158 absorbent shell section

[0207] 158' IR image absorbing hull section

[0208] 160 bases

[0209] 162 recess

[0210] 164 collars

[0211] 166 Opening

[0212] 168 Dome / Cap

[0213] 170 sterile patient drape

[0214] P Patient

Claims

Claims 1 . Sterile cover (1; 101) for at least partially covering a medical, in particular surgical, navigation tracker (2; 102), in particular for being placed over the navigation tracker (2; 102).

2. Sterile cover sheath (101) according to claim 1, characterized in that the sterile cover sheath (101) has at least two transparent, dimensionally stable sheath sections (154), each of which serves to receive an individual navigation marker (22) of a navigation tracker (2; 102), and a dimensionally flexible sheath section (158) by means of which the transparent, dimensionally stable sheath sections (154) are connected to one another.

3. Sterile cover sheath (101) according to claim 1 or 2, characterized in that the sterile cover sheath (101) has at least one transparent sheath section (154) which is transparent for a specific wavelength range, in particular infrared radiation, in order to cover a navigation marker (22) of the navigation tracker (2; 102) in a transparent (detectable) manner for this wavelength range, and the sterile cover sheath (101) has at least one absorbent sheath section (158) which is absorbent for the specific wavelength range, in particular infrared radiation, in order to cover, in particular in an area of ​​the navigation tracker (2; 102) to be covered by the absorbent sheath section (158),102), to minimize or even prevent reflections for this wavelength range, wherein the absorbent casing section (158) is formed at least partially to be dimensionally loose, and / or that the absorbent casing section is formed at least partially to be dimensionally stable, and that the absorbent casing section is dimensioned such that it covers at least one support structure (124) of the navigation tracker (102); 4. Sterile cover sheath (101) according to 3, characterized in that the absorbent sheath portion (158) has at least one recess (162) into which the at least one transparent sheath portion (154) is inserted.

5. Sterile cover sleeve (101) according to claim 4, characterized in that the at least one transparent sleeve section (154) has a circumferential collar (164) or flange with a greater width or dimension, in particular diameter, than the recess (162), and that the collar (164) or flange is connected to an edge or edge region of the recess (162), in particular in a materially bonded manner, in particular by means of an adhesive connection or ultrasonic welding connection, in particular in order to form a hermetic connection for a sterile barrier.

6. Sterile cover sleeve (101) according to one of claims 2 to 5, characterized in that the at least one transparent sleeve section (154) extends at least partially in a hollow cylinder and has an opening (166) at one end section, in particular bordered by the collar (162) or flange, for inserting one of the navigation markers (22), and at another end section a dome (168), in particular a part-spherical or hemispherical one, for at least partially concentrically receiving and covering one of the navigation markers (22).

7. Sterile cover sleeve (101) according to one of claims 2 to 6, characterized in that the at least one transparent sleeve section (154) for receiving one of the navigation markers (22) is designed with a cap shape or hat shape or knob shape, preferably a melon hat shape.

8. Sterile cover sleeve (101) according to one of claims 2 to 7, characterized in that the at least one transparent sleeve section (154) is formed from transparent plastic, in particular PS, PC, PMMA or PETG, in particular is plastic-injected. 9 Sterile cover sheath (101) according to one of claims 2 to 8, characterized in that the transparent sheath section (154) is designed in the form of a rigid, dimensionally stable cover cap, which is adapted to be plugged or pulled over the navigation marker (22), and in particular has a peripheral flange at the end which is arranged radially outward, and this flange is connected to the absorbent cover section by means of a materially bonded connection, wherein preferably the cover cap projects through a cross cut of a sterile patient drape (170) as an absorbent cover section (158) and is connected to the latter.

10. Sterile cover sheath (1) according to claim 1 for being thrown over a medical, in particular surgical, navigation tracker (2), characterized in that the cover sheath (1) has a sheath (4) which is at least partially transparent and an envelope collar (6) which are designed and dimensioned to accommodate the navigation tracker (2), wherein the envelope collar (6) predetermines or defines an envelope opening (8) in an unloaded state and the envelope collar (6) is or has a weight, in particular has a higher density than the sheath (4), in order to tighten the sheath (4) at least partially by means of gravity by means of its own weight when the cover sheath (1) is thrown over the navigation tracker (2).

11. Sterile cover sleeve (1) according to claim 10, characterized in that the sleeve collar (6) projects outwards from the sleeve (4) normally or projects outwards from the sleeve (4) at an obtuse angle, and in that the sleeve collar (6) extends completely, in particular rotationally symmetrically, around the sleeve opening (8).

12. Sterile cover sleeve (1) according to claim 10 or 11, characterized in that an adhesive layer (44), in particular an adhesive layer, is applied to the envelope collar (6), preferably on an upper side or an outwardly facing side or a side of the envelope collar (6) facing away from the envelope opening (8), wherein the said side points in particular in the direction of a longitudinal extent of the sleeve (4) and / or against a direction of gravity, so that an additional, sterile cover (48) can be bonded to the adhesive layer (44) in a material-to-material manner and can thus be fixed, wherein the adhesive layer (44) is preferably prepared covered with a removable protective film (46).

13. Sterile cover sheath (1) according to one of claims 10 to 12, characterized in that the sheath (4) has a reinforcing section or stiffening section or that a reinforcing section (30) or stiffening section is arranged on the sheath (4), which is provided and designed so that after being thrown over the navigation tracker (2), the sterile cover sheath (1) is stretched in a stiffened manner in a region of the reinforcing section (30) or stiffening section and tracks a defined geometry.

14. Sterile cover sleeve (1) according to one of claims 10 to 13, characterized in that the sleeve (4) has a transparent and dimensionally stable sleeve section (4'), preferably a see-through pane, which is provided and designed such that, after being thrown over the navigation tracker (2), the transparent and dimensionally stable sleeve section (4') allows a view of the navigation markers (22).

15. Sterile cover sleeve according to claim 14, characterized in that a clip (50) with at least two elastically deformable clip arms (52) arranged opposite one another is provided on the transparent and dimensionally stable sleeve section (4'), which clip is designed to engage around and behind a knob (28) or head of the navigation tracker (2) and thus to lock with the knob (28) or head, and / or that at least one clip with at least two elastically deformable clip arms arranged opposite one another is provided on a transparent and dimensionally stable sleeve section, preferably on an edge of the flat, transparent and dimensionally stable sleeve section, which clip is designed to lock with a spacer, preferably on the edge, of a support structure of the navigation tracker.

16. Sterile cover sleeve according to one of claims 10 to 15, characterized in that separate, transparent and dimensionally stable caps (54) are provided, which are designed such that when put over, the respective cap (54) can be placed on the navigation marker (22) there, so that the sleeve (4) can be tightened and / or fixed to the navigation marker (22) there by the respective cap (54).

17. Medical navigation tracker (2; 102) for spatial tracking, with a support structure (24; 124) on which navigation markers (22) are arranged, which are designed in particular actively as IR light-emitting diodes or passively as IR reflector bodies.

18. Medical navigation tracker (102) according to claim 17, characterized in that the support structure (124) is designed to be absorbent for a specific wavelength range, in particular for infrared radiation, at least on one side having the navigation markers (22), in particular has a low degree of reflection in order to minimize or even prevent reflections for this wavelength range.

19. Medical navigation tracker (102) according to claim 18, characterized in that the support structure (124) has a dark color and / or is black and / or matte at least on one side having the navigation markers (22), and has at least a surface made of plastic or blasted metal.

20. Medical navigation tracker (2) according to claim 17 for spatial tracking with a support structure (24) designed as a cross or as a star, at the end sections of which a navigation marker (22) is arranged, which is in particular actively designed as an IR light-emitting diode or passively as an IR reflector body, characterized in that adjacent to at least one of the navigation markers (22), preferably adjacent to each of the navigation markers (22), at least one spacer (26, 28; 27) is arranged, which extends in a direction transverse to a plane spanned by the navigation markers (22), so that by it or in cooperation with it a sterile cover sleeve (1) is held or maintained at a distance from the navigation marker (22). 21 . Medical navigation tracker (2) according to claim 20, characterized in that the at least one spacer (27) is arranged on the support structure next to the respective navigation marker and projects transversely to the plane or surface beyond the respective navigation marker (22), or that the at least one spacer (26) is designed in the form of a bracket hook which extends outwards, in particular radially outwards, from the support structure (24), wherein a plane of the bracket hook is perpendicular to the plane spanned by the navigation markers (22).

22. Medical navigation tracker (2) according to claim 20 or 21, characterized in that at least one central spacer (28) is arranged on the support structure (24) centrally to the navigation markers (22), which spacer extends transversely to the plane or surface spanned by the navigation markers (22) beyond the navigation markers (22), and which is designed, in particular, in the form of a knob or head with an undercut, to be encompassed and engaged behind by a clip (50) of the sterile cover sleeve and thus to be locked to the clip (50), and in that the sterile cover sleeve (1) is held or maintained at a distance from the navigation markers (22) by the central spacer (28) in cooperation with the at least one spacer (26) arranged on the outside, in particular radially on the outside.

23. Sterile cover system (20; 120) with a navigation tracker (2; 102) according to one of claims 17 to 22 and a sterile cover sheath (1; 101) according to one of claims 1 to 16.

24. Sterile cover system (20; 120) according to claim 23, characterized in that the navigation tracker (102) is covered by the sterile cover sheath (101) or the sterile cover sheath (1) is thrown over the navigation tracker (2).

25. Sterile cover system (120) according to claim 23 or 24, characterized in that the navigation markers (22) are each received in one of the transparent sleeve sections (154) and are covered and / or enclosed by the transparent sleeve sections (154) in a transparent and sterile manner for the specific wavelength range.

26. Sterile covering system (120) according to claim 25, in particular with a sterile covering sleeve (101) according to one of claims 2 to 9, characterized in that bases (160) of the support structure (124), from which the navigation markers (22) each project, are each elastically encompassed by one of the transparent sleeve sections (154), so that the transparent sleeve sections (154), in particular via an O-ring or a snap ring with a round cross-section, are locked and / or coupled to the support structure (124), so that the transparent sleeve sections (154) are arranged in a precisely positioned and / or concentric manner to the navigation markers (22).

27. Sterile cover system (20) according to claim 23 or 24, characterized in that the navigation tracker (2) is accommodated in the sterile cover sheath (1), and that the sheath (4) of the sterile cover sheath (1) is tightened by means of the dead weight of the sheath collar (6) of the sterile cover sheath (1) and by means of gravity, and that the sterile cover sheath (1), in particular its sheath (4), is held at a distance from the navigation markers (22) by means of the spacers (26, 28; 27) of the navigation tracker (2).

28. Sterile covering system (20) according to claim 24, characterized in that the cover (4) is held pyramidally at a distance from the navigation markers (22) by the spacers (26) arranged on the outside, in particular radially on the outside, and the central spacer (28), or that the cover (4) is held flatly at a distance from the navigation markers (22) by the spacers (27) arranged next to the navigation markers (22), and in particular by the central spacer.

29. Sterile cover system (20) according to claim 24, characterized in that the navigation tracker (2) according to claim 21 and the sterile cover sleeve (1) are designed according to claim 14, and that a knob (28) or head of the navigation tracker (2) is encompassed and engaged behind by the clip of the sterile cover film (1) and thus the knob (28) or head is locked to the clip (50) and the transparent and dimensionally stable sleeve section (4') is fixed to the navigation tracker (2).

30. Sterile cover system (20) according to claim 29, characterized in that the transparent and dimensionally stable cover section (4') is supported on the spacers (26, 28).

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