In the following detailed description of the invention, further features of the invention are disclosed. Different features of different embodiments may be combined.
FIG. 1 shows an embodiment of a navigation system of the present invention, a support arm structure, a holding system of the present invention and a holding device of the present invention.
FIG. 2 shows a holding system of the present invention;
FIG. 3 shows a lock ring and outer disc;
FIG. 4 shows a holding system of the present invention before fastening of the holding device to the device support;
FIG. 5 shows the fastening of a holding device to the device support;
FIG. 6 shows an instrument holded by the holding system of the present invention;
FIG. 7 shows releasing of the lock ring and the outer ring from the instrument;
FIG. 8 shows releasing of the inner ring and device support from the instrument.
FIG. 1 shows a setup for positioning biopsy needles. An embodiment of the holding system 100, 200 of the present invention is attached to the end 310 of a flexible support arm structure 300. Joints 320, 330, 340, 350, 360, 370, and 380 allow a free positioning of the end 310 of the support arm structure. For instance, the head of a patient may be placed between the embodiment of the invention 100, 200 and a support bracket 390 of the support arm structure 300 which supports the arm of the support arm structure 300. The holding system 100, 200 of the present invention is constituted to a hold biopsy needle in order to position at the needle exactly in the head of the patient. Alternatively to the support arm structure other support devices like stereotactic frames may be used in order to hold the holding device or holding system of the present invention.
Besides the support arm structure other parts of a navigation system of the present invention is shown. A detection unit, in particular camera unit 10 is connected to a data processing unit 20 which processes the detection data. The camera 10 detects for instance infrared light reflected from marker units, in particular from marker balls 236 shown in FIG. 1 or other marker balls 1, 2, 3, 4, 5 and 6 shown in FIG. 5. The data are processed in known manner in order achieve a navigation of the holding system in three-dimensional space. In particular and optionally and not obligatory, the navigation system may be used to register the inner disc 110 by using a pointer as described when discussing FIG. 4 below. Information for the user based on the processed data is shown on a screen 30.
The holding system of the present invention is shown in more detail in FIG. 2. The holding system of the present invention comprises a holding device 100 (shown in dark grey) and a device support 200 (shown in light grey). The device support 200 is attached to the end 310 of the support arm structure 300 (shown in FIG. 1) by the joint 320. Loosening of the joint 320 allows movement of the device support 200 in the directions B (translational) movement and D (rotational movement).
The device support 200 comprises a joint 220 which may be loosened by the screw 222 in order to achieve a rotational movement A around an imaginary axis 500. Preferably, a joint is provided which allows only rotation around the axis 500 and to do not allow movements concerning other mechanical degrees of freedom. Since, in case the holding device is fastened to the support device, the axis 500 corresponds to the axis of symmetry of the holding system, an exact positioning is made easier. In the embodiment shown in FIG. 2, the device support 200 comprises two parts, a part 230 and a part 240. The part 230 is rotatable relative to the part 240 around the axis 500. The part 230 is connected with a leg 234 of a reference array which allows the attachment of marker balls (of a marker unit) at its end. The marker balls are detectable by a navigation system and are in particular passive reflecting marker balls which reflect for instance light.
The holding device 100 shown in FIG. 2 consists of three parts which are called inner disc 110, outer disc 120 and lock ring 130. The combination of the inner disc 110 and the outer disc 120 represent an example for a holding site unit. The inner disc 110 and outer disc 120 are used for defining holding sites for holding the instruments (e.g. biopsy needle). The lock ring 130 is used for both fastening the holding device 100 to the device support 230 and for clamping an instrument at the selected holding site.
FIG. 3 shows the lock ring 130 and the outer disc 120 in more detail. In particular it is obvious from FIG. 3 that the lock ring 130 and outer disc 120 are detachable from each other. Preferably, the lock ring 130 and the outer disc 120 may be coupled by means of a snap mechanism. A snap projection (not shown) is provided in the lock ring 130 which may snapingly engage into a groove 122 of the outer disc 120. If coupled by the snap mechanism, a relative translational movement along the axis 500 of the outer disc 120 and the lock ring 130, which would separate the lock ring 130 from the outer disc 120, is blocked. On the other hand, the projection (not shown) may slide in the groove 122 in order to allow a rotational movement of the lock ring 130 relative to the outer disc 120 around the axis 500 in the rotational direction A (or counterwise to A).
FIG. 4 shows an embodiment of the holding system of the present invention. The device support 230 is separated from the inner disc 110. The inner disc 110 is separated from the outer disc 120 which is coupled to the lock ring 130.
The inner disc 110 is formed in a ring-like manner. In the example shown, the outer circumference of the inner disc 110 follows the path of a circle or ring. The wall of the inner disc 110, the outer circumference of which follows the path of the circle or the ring will be referred to as ring wall in the following. The ring wall has two end faces. An inner end face which faces the device support 230 and an outer end face 112 which faces the outer disc 120. Furthermore the ring wall has the outer circumference (called “outside of the ring wall”) and the inner circumference (called “inside of the ring wall”). The inner end face of the ring wall is preferably continuously and shaped as a ring. The outer end face 112 is interrupted by recesses 114. The recesses 114 cooperate with corresponding, insertable projections in order to form holding sites for the instruments and to define the holding spaces in particular of a particular (maximum) holding size. The recess 114 represents an example for an inner part of a holding site. Preferably, the recesses 114 consist of three parts. An outer part 114a of the recess 114 which has the shape of a cone-like recess and comprises two walls (called “truncated walls” 114a) facing each other and being inclined towards the inner side (i.e. towards the support device 230) such that they become more and more closer towards the inner side. A second part 114b (called “parallel walls” 11b) of the recess 114 is preferably formed by two parallel walls which are aligned parallel to an axis. The axis coincides with the aforementioned axis 500 in case the holding device is fastened to the support device. The axis of the inner disc 110 is preferably the central axis of the ring wall. Preferably, all recesses 114 are equidistant to the axis of the inner disc 110. The third part 114c (called “ring section wall” 114c) of the recess 114 is preferably shaped like a ring section and connects the parallel walls 114b.
The inner disc 110 comprises a plurality of recesses. In the example shown there are eight recesses. Preferably, the recesses are located at opposing sides (with respect to the axis of the inner disc) and are identical in shape. Preferably, the recesses, in particular the ring section walls 114c of opposing recesses are aligned along a straight line which passes through the axis of the inner disc such that a rod shaped instrument having circular cross section the diameter of which coincides with the diameter of the ring wall section 114c, abuts against the two ring section walls 114c which are located opposite to each other. In the example shown in FIG. 4, the recesses designated as 114 and 114′ are located opposed to each other and are identical in shape and size.
Since in the example given in FIG. 4, all recesses and projections located at opposing sides of the axis are identical in shape and size, there are provided four different sizes of holding spaces (i.e. half of total number of recesses) along the ring wall of the inner disc.
This allows to insert instruments of different cross sections into the respective recess pairs (114 and 114′) which are located opposed to each other.
As can be seen by the inscription at reference number 118, the recess 114 (and its opposing counterpart 114′) are meant for accommodating the rod shape part of an instrument which has a cross section between 3.0 mm and 4.0 mm. This means in case of a diameter of 4.0 mm the rod shape instruments fully contacts the ring section wall 114c, i.e. the radius of the ring section wall 114c coincides with the radius of the rod shaped instrument.
Preferably, the recesses 114, and in particular the ring section walls 114c, the parallel walls 114b and the truncated walls 114a extend in a groove-like manner towards the axis of the inner disc in order to define a channel for inserting and holding a rod-shaped instrument. This extension in a groove-like manner is preferably longer than the diameter defined by the ring section walls in order to have a good guidance and stability of the held instrument.
Furthermore, pointer recesses 115 are provided which allow the insertion of a pointer in order to register and/or calibrate the holding device. This feature is optional. Generally, the position of the holding device is known due to a fixed spatial relationship between the holding device and the device support. In that case, the pointer recesses may be used (optionally) to check the correctness of the known position. Pointers are for instance instruments having a marker unit of two or more markers (e.g. marker balls). The spatial relationship between the markers and the tip of the pointer is known. The pointer is observed by a navigation system, in particular comprising a camera, when the tip of the pointer is inserted in the pointer recesses 115. In this way, the location of the inner disc 110 may be registered in three dimensional space and/or the type of holding device, in particular the type of inner disc may be identified. Different type of holding devices, in particular inner discs (and corresponding outer discs) may vary in the size of the recesses in order to allow differently sized instruments to be hold. In case the holding device is fastened to the device support 230, the location of the recesses 114 may be determined from the location of the pointer recesses 115. The registration process thus allows to determine the location of an instrument holded by the holding device of the present invention. For instance, the pointer recesses may have particular and e.g. unique spatial relationship with respect to each other allowing to determine which of the printer recesses is close to which of the holding sites (114, 124).
The ring wall of the inner disc 114 is ring-shaped at the outside while it is polygonal-shaped at the inside. The inside has n plane sections 116 arranged in a closed loop. In more detail, in the example (n=8) shown in FIG. 4, the inside of the ring wall has an octagonal shape (n=8). The octagonal shape is defined by eight adjoining plane sections 116 extending parallel to the axis of the inner disc and surrounding the axis in equal distances from the axis. The arrangement of plane sections, i.e. the planes represent an example for the holding device coupling unit. Each plane section 116 comprises one of the recesses 114. Preferably the recesses 114 extend in the middle of the plane sections 116 of the polygonal (in particular octagonal) inside of the inner disc towards the holding device 230 and parallel to the axis of the inner disc. The axis of the inner disc 110 (and also of the lock ring 130 and of the outer disc 120) coincide with the axis 500 of FIG. 1, in case the holding device 100 is fastened to the device support 200.
The polygonal inside of the inner disc 110 comprising in particular plurality of plane sections 116 (and representing an example for a coupling unit) is preferably constituted to mutely engage with a polygonal structure 236 of the device support 230 in order to achieve at least partly a form closure (form fitting) between the holding device 100 and the device support 200. The engagement may be for instance such that the polygonal inside of the inner disc 110 encompasses and in particular contacts the polygonal structure 236 when the holding device is fastened to the device support. In this way, when fastened, a relative rotation between the device support 230 and the inner disc 110 is blocked due to a polygonal form fitting (form closure) between the polygonal structure 236 and the polygonal inside of the inner disc 110. Thus, a rotation around the axis 500 may be blocked and in particular a definite angular relationship between the holding device 100 and the device support 200 may be set (i.e. one of the plurality of coupling angles may be selected). Preferably, the polygonal structure 236 and the polygonal inside of the inner disc 110 are complementary shaped. Preferably, the polygonal structure is such that the angles defined by the edges of the polygon are equal. This allows to set a distinct number of relative angles between the device support and the inner disc (or holding device).
Preferably the difference between adjoining relative angles is equal (e.g. 45° in case of octagonal structure).
In the example shown, an octagonal structure allows to set eight different relative angles (coupling angles) between the device support 300 and the holding device 100.
In order to achieve a coupling in axial direction between the inner disc 110 and the device support 230, a coupling mechanism may be provided. The coupling allows to releasably block movement in axial direction and to set a fixed spatial relationship in axial direction. As shown in FIG. 4, a ball 236 representing a press bearing which presses the ball outwards, i.e. away from the axis 500, is provided in one of the (eight) plane faces of the polygonal structure 236. The ball 236 may be pressed inwards in order to attach the inner disc 110 to the device support 230. The ball 236 engages with a groove 117 provided in the polygonal inside of the inner disc 110, i.e. in the plane sections 116 of the polygonal inside of the inner disc. The groove 117 is preferably arranged close to the end face of the inner disc 110 which faces the device support 230, i.e. is preferably close to the inner end face.
The outer disc 120 shown in FIG. 4 (and FIG. 3) has projections 124 meant for the insertion into the recesses 114 of the inner disc 110 in order to form holding sites for the instrument. The projections 124 represents an example for an outer part of the holding site. The projections 124 are shaped preferably but not obligatory such that the outer end faces 112 of the inner disc 110 may come in contact with the inner end faces (not shown) of the outer disc 120 which face towards the inner disc. Projections 124 consist of three parts, a first part 124a which is formed complementary or approximately complementary to the truncated wall 114a of the inner disc. The truncated walls 124a of the outer disc at opposite side of each projection are inclined towards each other in the inner direction, i.e. towards the device support. Subsequent to the truncated walls 124a there are parallel walls 124b which further extend towards the inner side, i.e. towards the device support. The end of the projection 124 which faces the inner disc 110 and in particular the ring sections wall 114c has a V fornation 124c. The open side of the V is meant to face a compatible ring section wall 114c.
The distance between the open ends of the V formation 124c corresponds approximately to the diameter of the associated ring section wall. Preferably and not obligatory, the distance between the open ends of the V formation 124c is between 80% or 90% and 100% of the diameter of the associated ring section wall 114c, preferably between 95% and 100%, more preferably between 98% and 100%. Preferably the ring section walls 114c extend along half of a circle such that the ends of the ring section wall define a full diameter of a circle which corresponds to a maximum diameter of an instrument insertable in the holding space. In particular a maximum holding size for a rod shaped instrument is defined by the maximum diameter.
The V formation in corporation with the ring section wall 114c allows to set rod shaped instruments of varying diameters into the holding site which is respectively formed by a ring wall section 114c of a inner disc 110 and a V formation 124c of the outer disc 120. Furthermore the surface of the ring wall section 114c and the surface of the V formation 124c define the holding space for holding the instrument and the available holding size. In case the diameter of the cross section of the rod shaped instrument is less than the diameter of the ring section wall 114c, a contact at least three points between the instrument and the inner and outer disc 110, 120 is assured due to the geometry of the ring section wall 114c and the V formation 124c. As shown in FIG. 4 at reference sign 118, the corresponding recess 114 is suitable to accommodate rod shaped instruments, the cross section of which correspond exactly to the ring section wall (in the example 4.0 mm) as well as rod shaped instruments of smaller diameter below 4.0 mm. The preferred minimum diameter is in the example 3.0 mm. Preferably, the minimum diameter is about 10% to 30% or 40% smaller than the maximum diameter, more preferably at maximum 25% smaller than the maximum diameter in order to assure exact positioning of the instrument. Due to providing a plurality of holding sites which are easily changeable for an operator, the range between the preferred minimum diameter and the maximum diameter may be reduced.
In case an instrument is inserted between the inner and outer disc as can be seen in FIG. 6, the distance between the inner disc 110 and the outer disc 120 may vary in dependence on the diameter of the holded instrument. In case the diameter of the instruments is equal to the maximum diameter of the recess in which the instrument is holded (i.e. clamped between 114c and 124c), then there is a maximum use distance between the inner disc 110 and the outer disc 120 when the holding device is fastened to the device support in use. This maximum distance is reduced if the instrument is replaced by an instrument of smaller diameter which is holded within the same recess. This results in a shift of the center (imaginary) axis of the rod shaped instrument with respect to the device support 230. In order to measure and detect this shift, a reference array 119 comprising at least one marker, preferably a marker unit of plurality of markers may be attached or integrated in the outer disc 120. This is shown as a marker unit 129 in FIG. 5 which is attached to the outer disc 120. Furthermore, an option is to attach a marker unit 119 to the inner disc 110. Alternatively or additionally the pointer recesses 115 may be checked by a pointer or may be replaced by markers, in particular of different size. By using the marker units 119 and 129, the relative position of the inner disc 110 and outer disc 120 may be detected. In particular based on the detection of the marker unit 119 and/or 110 it may beautomatically detected which of the holding sites is used for holding an instrument in order to determine the position of the instrument and/or cross section of the instrument, in particular by (additionally) detecting a marker unit attached to the instrument. In particular, a shift of the central axis of the instrument may be detected by using the marker unit 129. The position of the marker unit 129 relative to the marker unit 119 of the inner disc and/or the marker unit 234 of the device support may be used in order to determine the positional shift of the central axis of the instrument. Furthermore, depending on the shift of the central axis with respect to the position of the central axis in case an instrument of maximum diameter is inserted in one of the recesses, it may be determined whether the inserted instrument is within the preferred range, i.e. whether the diameter of the instrument is above or equal to the preferred minimum diameter. In case, the instrument is below the preferred minimum diameter, this may be detected and a user information procedure may be initiated by the navigation system. In particular, a proposal may be given to choose another holding site more suitable for the instrument, i.e. where the diameter is within the preferred (and proposed) range of diameters. In particular, a warning signal may be issued.
Alternatively to or additionally to providing the marker units 119 and/or 129 at the inner disc and/or outer disc, for instance an RFID detection unit may be provided which contacts a RFID chip in the instrument in order to determine its type, in particular the cross section of its rod part to be hold or held. Based on the data and based on the detection of the used recess, it may be determined whether the inserted instrument or instrument to be inserted is within the preferred holding size range or not and whether the navigation system should for instance initiate the above-mentioned procedure to warn and/or inform the user if the instrument is outside the preferred range. Preferably, the navigation system assumes that a holding site at a predefined holding angle with respect to the device support, e.g. the uppermost holding site, is the site intended for holding the instrument and/or the navigation system determines by means of a marker unit comprised by the instrument which holding site is used by the instrument.
As described with respect to FIG. 3, the lock ring 130 may be rotated relative to the outer disc 120. The lock ring 130 comprises hand-gripping faces 132 which ease the rotation of the lock ring for an operator. This hand-gripping faces are provided on the circumferential outside of the lock ring 130. The circumferential inside of the lock ring 130 is provided with a thread 137. The grooves of the thread 137 surround in a spiral manner the axis 500 which represents in particular an axis of symmetry in case the holding device is fastened to the device support. The thread 137 is constituted to engage with a complementary thread 237 provided on the device support 230. The complementary thread 237, as shown in FIG. 4 is provided on the outside of two walls which represent sections of a cylinder which surrounds the aforementioned axis 500. The sections are separated by a gap 238 in order to allow the passing of an instrument. Thus the distance of the gap is preferably equal or larger than the extension of the largest holding size in circumferential direction. Preferably, the extension of the thread in axial direction is longer than the extension of the lock ring 130. This allows to loosen the held instrument while still having a reliable seat of the lock ring 130 on the thread 237. Loosening of the instrument allows to adjust the position of the instrument, in particular perpendicular to the axis of the holding device.
When the lock ring 130 is rotated as shown by the arrow A in FIG. 5, and if the thread 137 is in contact with the complementary thread 237 of the device support 230 while the inner disc and outer disc are between the device support 230 and the lock ring 130 (as shown in FIG. 4), then the inner disc, outer disc and lock ring are fastened to the device support 230 while the projections 124 engage in their complementary recesses 114 as shown in FIG. 5.
As shown in FIGS. 4 and 5, due to the octagonal structure and the equal shape of opposing recesses or projections, four different diameter ranges for attaching an instrument are provided by the holding device according to the invention.
Preferably, an instrument 600 as shown in FIG. 6 has a particular orientation relative to the device support 230. The present invention allows to maintain this relative orientation while using instruments 600 of different cross section. This is done by rotating the inner disc 110 with respect to the device support 230 in one of the plurality of attachable positions (in the example 8 possible positions). In the shown example, the inner disc is rotated such that the uppermost (and thus also the lowermost) recess has a diameter range suitable for the instrument to be attached. The outer disc 120 is brought into an angular relationship with respect to the inner disc 110 such that all (complementary) projections 124 fit into their complementary recesses when the outer disc 120 is moved towards the inner disc when the lock ring 130 is rotated to engagement with the thread 237. The sense of rotation is shown as A.
FIG. 7 shows detachment of the instrument 600 from the inner disc 110. The instrument 600 passes through a recess 114 and through the gap 238 in the two cylindrical sections 231 and 232. In the situation shown in FIGS. 6 to 8 it may be assumed that the instrument 600 has not only be attached to the holding system of the present invention 100, 200 but that the end of the instrument is inserted in a biological tissue, e.g. brain of a patient. In this situation, it may be preferred to remove the holding system of the present invention. For this purpose, the ring lock is rotated in direction A′ (which is counter to the sense of rotation for fastening) in order to detach the ring lock 130 from the device support 230 as shown in FIG. 7. Since the ring lock 130 is coupled with the outer disc 120 by a snap mechanism, the ring lock 130 automatically removes (catches) the outer disc 120 when the ring lock is detached. The inner disc 110, together with the device support 230, may then be detached from the instrument 600 as shown in FIG. 8. The instrument 600 stays in the biological tissue for further use.
A particular advantage of the present invention is that the inner disc and outer disc may be removed sideward from the instrument, i.e. in a direction perpendicular to the longitudinal extension of the instrument. This is of particular advantage if the instrument comprises two coextending elements, for instance an inner element and an outer element surrounding the inner elements. An example for this is a catheter, which includes a wire for guiding the catheter and a pipe which surrounds the wire. By removing the inner disc and outer disc, the position of the outer part (tube or pipe) is not changed or affected as in some of prior arts systems where the holding device has to be removed from the instrument along the longitudinal extension direction of the instrument.
Patent Application
20080086150
