METHOD AND DEVICE FOR THE DETERMINATION OF REDUCTION PARAMETERS FOR THE SUBSEQUENT REDUCTION OF A FRACTURED BONE

Abstract: The method for the determination of reduction parameters comprises: A) measuring points on the surfaces of the corresponding bones of interest at the patient's left and right side of the body; B) establishing a plane of symmetry containing an anterior-posterior axis and a proximal-distal axis; C) a mirror image of the patient's non-fractured bone is generated symmetrically to the plane of symmetry; and D) the reduction parameters are then determined by comparison of the coordinates of the points at the fractured bone with the coordinates of the points within the mirror image. The device according to the invention comprises: A) a cylindric or prismatic reference bar; B) clamps displaceable on and fastenable to the reference bar; C) screws or pins screwable into the bone transversely to the reference bar within the clamps; and D) an adjustable clamp to fasten a pin capable of being set with its tip to desired points on the surface of the bone.

Description: Method and Device for the determination of reduction parameters for the subsequent reduction of a fractured bone The present invention relates to a method for the determination of reduction parameters for the subsequent adjustment of a reduction device in order to reduce the fragments of a fractured bone as defined in the preamble of claim 1 and to a device for the determination of reduction parameters for the subsequent adjustment of a reduction device in order to reduce the fragments of a fractured bone as defined in the preamble of claim 5 In the field of osteosynthesis bone fragments of a patient's fractured bone must often be correctly relocated Only after such a correct relocation (reduction) of the bone fragments a fixing device such as an external or internal fixator may be applied in order to fix the bone fragments in a rigid position In other applications, wherein the patient has a bone malformation for example, the bone or bones must be treated At present the dislocation of fragments of fractured bones must be determined by means of X-ray imaging In case of installing a external fixator the corrections to be made through adjustment of the respective clamps and pins or screws bases on these X-ray images The verification of the reduction of the fractured bone by means of the external fixator must be effected with subsequent X-ray imaging This procedure may be cumbersome in case of multiple steps of adjustment of the fragments On this point, the invention intends to provide remedial measures The objective of the invention is to provide a method and a device based on the idea of a comparison of the bone contour of the fractured bone with the corresponding healthy bone on the patient's healthy side of the body without using X-ray imaging The invention solves the above problem by means of a method for the determination of reduction parameters for the subsequent adjustment of a reduction device in order to reduce the fragments of a fractured bone offering the features of claim 1 and a device for the determination of reduction parameters for the subsequent adjustment of a reduction device in order to reduce the fragments of a fractured bone offering the features of claim 5 The method according to the invention comprises the following steps A) the determination of the reduction parameters is performed by means of a comparison of the contour of the corresponding bones of interest at the patient's left and right side of the body, whereby B) the positions of at least three non-collinear points at one of the bones of interest are determined, therewith establishing a three-dimensional coordinate system with respect to the body of the patient, C) the positions of the identical points at the other bone of interest and within the coordinate system are determined whereby the determination of the points is effected such that the at least three points are situated on the proximal fragment of the fractured bone, D) a plane of symmetry containing an anterior-posterior axis and a proximal-distal axis is established by means of dividing the connecting vectors between each point and its corresponding point in two equal parts therewith defining central points of the vectors which determine three points of the plane of symmetry within the coordinate system, D) a mirror image of the patient's non-fractured bone is generated symmetrically to the plane of symmetry by means of determining at least three non-collinear points at the non-fractured bone at each section corresponding to a fragment of the fractured bone and by forming the mirror image by determination of the points that are symmetrical to the points with respect to the plane of symmetry, E) the positions of at least three points at each fragment of the fractured bone and corresponding to the points at the non-fractured bone are determined, and F) the reduction parameters are then determined by comparison of the different coordinates of the points at the fractured bone with the coordinates of the points within the mirror image The coordinates are preferably measured within the coordinate system defined under step B) The determination of the reduction parameters is then preferably executed by means of calculating the differences between the coordinates of the points at the fractured bone and the coordinates of the points within the mirror image in the medial-lateral direction, the anterior-posterior direction and the proximal-distal direction. In a preferred realization of the method according to the invention the determination of the position of the points on the surface of the fractured and the non-fractured bone is performed by means of touching these points with the tip of a pointer which is provided with at least three markers whose position is determinable within an on-site three-dimensional coordinate system by means of an optical position measurement device and respective data management via a computer. The position measurement device may be an optical position measurement device, an accoustic position measurement device or a electromagnetic position measurement device. Corresponding to the mode of operation of the position measurement device the markers attached to the pointer may be energy emitting, receiving or reflecting means. For instance as energy emitting means: - Light sources; - Light emitting diodes (LED's); - Infrared light emitting diodes (IRED's); - Accoustic transmitters; or - Coils in order to establish a magnetic field; or as energy receiving means: - Photodiodes; - Microphones; or - Hall-effect components; may be installed. In yet another preferred realization of the method according to the invention it comprises A) the determination of the position of the at least three points at the surface of one of the bones by means of fastening one reference bar through two screws or pins to the bone and determining a third point with an adjustable pin fastenable to the reference bar, B) the determination of the position of the identical points at the surface of the other bone by means of fastening a second reference bar through two screws or pins to the other bone and determining the third point with an adjustable pin fastenable to the reference bar, and C) the coordinates of the tips of the adjustable pins relative to particularly defined points on the reference bars are compared in order to estimate the reduction parameters This method includes upon request a) the measurement of the reduction parameters relative to the medial-lateral plane by means of attaching one reference bar at the non-fractured bone in the medial-lateral plane and one reference bar at the fractured bone in the medial-lateral plane, b) the measurement of the reduction parameters relative to the anterior-posterior plane by means of attaching one reference bar at the non-fractured bone in the anterior-posterior plane and one reference bar at the fractured bone in the anterior-posterior plane, or c) the measurement of the reduction parameters relative to the medial-lateral plane and relative to the anterior-posterior plane by means of attaching one reference bar each at the non-fractured bone in the medial-lateral plane and in the anterior- posterior plane and one reference bar each at the fractured bone in the medial- lateral plane and in the anterior-posterior plane The method according to the invention is preferably performed by the surgeon as an additinal step during planning and preparation of the surgical treatment of the fractured bone as for example the selection of an adequate reduction apparatus and method as well as adequate internal or external fixators The device according to the invention comprises A) a cylindπc or prismatic reference bar having a longitudinal axis, B) clamps displaceable on the reference bar in the direction of the longitudinal axis and fastenable to the reference bar, C) screws or pins looseπable fixable transversely to the reference bar within the clamps whereby the screws are screwable into the bone therewith attaching the reference bar to the bone, and D) one or more adjustable clamps to loosenably fasten one or more pins capable of being set with their tips to desired points on the surface of the bone In a preferred embodiment of the device according to the invention the adjustable clamp is designed such that the tip of the pin is displaceable with three degrees of freedom therewith allowing to estimate the coordinates of the tip with respect to a three-dimensional coordinate system affixed to the reference bar To realize this displaceabi ty with three degrees of freedom the adjustable clamp comprises a socket, a post and a support whereby the support is slidable in the direction of the longitudinal axis of the post and the socket is slidable on the reference bar in the direction of the longitudinal axis of the reference bar Preferably the post is arranged perpendicularly to the reference bar and the support is provided with a bore hole for acceptance of the pin and with an axis extending perpendicular to the post and the reference bar In yet another embodiment of the device according to the invention articulated pins are provided to attach the reference bar to the bone Preferably the articulated pin is provided with a thread at its end being introduced into the bone As joint of the articulated pin a turning knuckle having one degree of freedom or a ball joint may be provided The articulation is preferably loosenably fastenable The advantages of the invention are that the reduction parameters of a fractured bone may be determined without the need of X-rays of the bone of interest The invention and its further developments are elucidated below in relation to several illustratively embodiments partly shown in diagrammatic form Fig 1 illustrates the method according to the invention, Fig 2 illustrates a realization of the method according to the invention comprising a position measurement device and a computer, Fig 3 shows the preferred embodiment of the device according to the invention, Fig 4 shows an embodiment of the device according to the invention attached to a non-fractured bone, and Fig 5 shows an embodiment of the device according to the invention attached to a fractured bone Fig 1 illustrates the method according to the invention that contains the idea of a comparison of the bone contour of the fractured bone with the corresponding healthy bone on the patient's healthy side of the body The method according to invention serves for the determination of reduction parameters for the subsequent adjustment of a reduction device in order to reduce the fragments of the fractured bone 5 in order to obtain these reduction parameters the method according to the invention comprises the following steps A) the determination of the reduction parameters is performed by means of a comparison of the contour of the corresponding bones 5,27 of interest at the patient s left and right side of the body, whereby B) the positions of at least three non-collinear points 31 ,32 at one of the bones 5,27 of interest are determined, therewith establishing a three-dimensional coordinate system 35 with respect to the body of the patient C) the positions of the identical points 31 ,32 at the other bone 5,27 of interest and within the coordinate system 35 are determined whereby the determination of the points 31 ,32 is effected such that the at least three points 32 are situated on the proximal fragment 42 of the fractured bone 5, D) a plane of symmetry 34 is established by means of dividing the connecting vectors between each point 31 and its corresponding point 32 in two parts therewith defining central points of the vectors which determine three points of the plane of symmetry 34 within the coordinate system 35, E) a mirror image 30 of the patient's non-fractured bone 27 is generated symmetrically to the plane of symmetry 34 by means of determining at least three non-collinear points 36 at the non-fractured bone 27 at each section corresponding to a fragment 40;41 ;42 of the fractured bone 5 and by forming the mirror image 30 by determination of the points 33 that are symmetrical to the points 36 with respect to the plane of symmetry 34; F) the positions of at least three points 39 at each fragment 40;41 :42 of the fractured bone 5 and corresponding to the points 36 at the non-fractured bone 27 are determined; and G) the reduction parameters are then determined by comparison of the different positions of the points 39 at the fractured bone 5 with the positions of the points 33 within the mirror image 30. In order to determine identical points 31 ;32 on the fractured bone 5 and at the non- fractured bone 27 anatomical landmarks may be used. For instance as anatomical landmarks anatomical ridges at the great trochanter proximally and on the lateral femoral condyle distally may be used. Fig. 2 illustrates a preferred realization of the method according to the invention whereby the determination of the position of the at least three points 31 at one of the bones 5;27 and the determination of the position of the identical points 32 at the other bone 5;27 is performed by means of touching the points 31 ;32 on the surface of the bones 5;27 with the tip 26 of a pointer 52 which is provided with at least three markers 53 whose position is determinable within an on-site three-dimensional coordinate system 54 by means of an optical position measurement device 56 and respective data management via a computer 57. This realization of the method according to the invention is preferably being used together with a Computer Assisted Surgery System (CAS). For instance, the position measurement device 56 may be an optoelectronic navigation system (Optotrak 3020, Northern Digital, CAN ) Correspondingly, the markers 53 may be infrared light emitting diodes (IRED's) that are detected by the position measurement device 56 therewith allowing to calculate the position of the pointer tip 26 within the three-dimensional coordinate system 54. Fig 3 illustrates the preferred embodiment of the device according to the invention This device 1 for the determination of reduction parameters at a fractured bone 5 comprises A) a prismatic reference bar 4 having a longitudinal axis 10 and a square cross section, B) two clamps 9 displaceable on the reference bar 4 in the direction of the longitudinal axis 10 and fastenable to the reference bar 4 by means of screws 14 that are screwed into bores containing interior threads within the clamps 5 and press onto the reference bar 4 when tightened, C) two screws 2,3 or pins with axes 13 loosenable fixable transversely to the reference bar 4 within the clamps 9 by means of screws 15 that are screwed into bores containing interior threads within the clamps 5 and press onto the reference bar 4 when tightened whereby the screws 2,3 are screwable into the bone 5 therewith attaching the reference bar 4 to the bone 5, and D) one adjustable clamp 12 to loosenably fasten a pin 11 capable of being set with its tip 26 to a desired point on the surface of the bone 5 The adjustable clamp 12 is designed such that the tip 26 of the pin 11 is displaceable with three degrees of freedom It comprises a socket 21 , a post 17 with a central axis 23 mounted rectangularly to the longitudinal axis 10 of the reference bar 4 on the socket 21 and a support 18 whereby the support 18 is slidable in the direction of the central axis 23 on the post 17 and the socket 21 is slidable on the reference bar 4 in the direction of the longitudinal axis 10 The support 18 is provided with a bore hole 25 for acceptance of the pin 11 and having an axis 26 extending perpendicular to the central axis 23 of the post 17 and perpendicular to the longitudinal axis 10 of the reference bar 4 Figs 4 and 5 illustrate the device 1 according to the invention once mounted at a non- fractured femur 27 and once mounted on the fractured femur 5 The device 1 comprises two adjustable clamps 12 with one pin 11 each Both devices 1 are attached to the bones 5,27 in the lateral-medial plane of the patient and symmetrical to a plane defined as described in fig 1 The coordinates of the points of the tips 26 of the pins 11 may be measured relative to the reference bar 4 and compared Furthermore, the device 1 shown in fig 5 is provided with articulated Once the reduction parameters, particularly the correction measures of bone length and angulation of the bone fragments of the fractured bone are determined the correction may be performed by means of a reduction device. The correction of the position of the bone fragments preferably begins with the correction of the bone length (ordinary distraction) followed by the correction of the angulation of the bone fragments in both the horizontal and the distal planes. These corrections are performed until the same parameters, particularly the corresponding coordinates within the reference coordinate system are received. During this correction the parameter data received from the non-fractured bone and transformed via the plane of symmetry (mirror) are used. Finally, the clamps 21 are moved into the fracture level one in the horizontal plane and one in the vertical plane. The tips of the pins assess the exact position of the fracture area in the horizontal and the vertical plane. Particularly the assessment of any overdistraction is performed which is followed by fine corrections of these small dislocations of the bone fragments. If a comminuted fracture is under procedure the final reduction via the above pin is not performed. Subsequently the measuring device is removed and the fixation of the bone can be performed. If an external fixator is intended to be applied the frame of a high mobile external fixator is fixed to the end remote of the bone of these pins that were already used when performing the reduction with a reduction device. If internal fixation is performed, minimally invasive methods of osteosynthesis are recommended. If the reduction device is computer controlled a particular software program may be used to receive the reduction parameter data from the non-fractured bone of the patient, transform these data via the plane of symmetry (mirror) into the reduction measures and control the motors of the already attached reduction device. By means of the motors the necessary corrections of the bone fragments is performed. Again the correction of the bone length (distraction) is firstly performed. Sensors at the reference bar, the clamps and the pins transmit digital signals to the computer until the correction is completed. One pin can be introduced into each bone fragment and introduced in a clamp. To provide an easier an automatic reduction the pin should be mounted at a right angle to the surface of the bone. The automatic reduction device is preferably provided with a control system which comprises sensors for measuring a probable over strength between the bone and reduction device connections. When this strength exceeds the allowed level the computer can switch the motors off or return the reduction device to a previous position such protecting bone and soft tissues from damage. After receiving this information the computer analyses again the position of the bone fragments and the motors may be controlled in order to perform more distraction or prevent collision of the bone fragments.

Claims: CLAIMS 1. Method for the determination of reduction parameters for the subsequent adjustment of a reduction device in order to reduce the fragments of a fractured bone (5), characterized in that A) the determination of the reduction parameters is performed by means of a comparison of the contour of the corresponding bones (5;27) of interest at the patient's left respective right side of the body; whereby B) the positions of at least three non-collinear points (31;32) at one of the bones (5;27) of interest are determined, therewith establishing a three-dimensional coordinate system (35) with respect to the body of the patient; C) the positions of the corresponding points (31 ,32) at the corresponding bone (5;27) of interest and within the coordinate system (35) are determined whereby the determination of the points (31 ;32) is effected such that the at least three points (32) are situated on the proximal fragment (42) of the fractured bone (5); D) a plane of symmetry (34) is established by means of dividing the connecting vectors between each point (31 ) and its corresponding point (32) in two parts therewith defining central points of the vectors which determine three points of the plane of symmetry (34) within the coordinate system (35); E) a mirror image (30) of the patient's non-fractured bone (27) is generated symmetrically to the plane of symmetry (34) by means of determining at least three non-collinear points (36) at the non-fractured bone (27) at each section corresponding to a fragment (40;41 ;42) of the fractured bone (5) and by forming the mirror image (30) by determination of the points (33) that are symmetrical to the points (36) with respect to the plane of symmetry (34); F) the positions of at least three points (39) at each fragment (40;41 ;42) of the fractured bone (5) and corresponding to the points (36) at the non-fractured bone (27) are determined; and G) the reduction parameters are then determined by comparison of the different positions of the points (39) at the fractured bone (5) with the positions of the points (33) within the mirror image (30). 2. Method as claimed in claim 1 , characterized in that the determination of the position of the at least three points (31) at one of the bones (5;27) and the determination of the position of the identical points (32) at the other bone (5,27) is performed by means of touching the points (31 ,32) on the surface of the bones (5,27) with the tip (26) of a pointer (52) which is provided with at least three markers (53) whose position is determinable within an on-site three-dimensional coordinate system (54) by means of an optical position measurement device (56) and respective data management via a computer (57) 3 Method as claimed in claim 2, characterized in that the points (31) at the non- fractured bone (27) and the identical points (32) at the fractured bone (5) are defined by means of fiducial markers (50,51 ) that were pre-operatively implanted 4 Method as claimed in claim 1 , characterized in that the determination of the position of the at least three points (31) at one of the bones (5,27) is performed by means of fastening at least one reference bar (4) through at least two screws (2,3) or pins to the bone (5,27) and determining a third point with an adjustable pin (1 ) and performing the determination of the position of the identical points (32) at the other bone (5,27) by means of fastening at least one reference bar (4) through at least two screws (2,3) or pins to the other bone (5,27) and determining the third point with an adjustable pin (11). 5 Device for the determination of reduction parameters at a fractured bone (5) according to the method according to one of the claims 1 or 4, characterized in that it comprises A) a cylindric or prismatic reference bar (4) having a longitudinal axis (10), B) at least two clamps (9) displaceable on the reference bar (4) in tne direction of the longitudinal axis (10) and fastenable to the reference bar (4), C) at least two screws (2,3) or pins with axes (13) loosenable fixable transversely to the reference bar (4) within the clamps (9) whereby the screws (2 3) are screwable into the bone (5) therewith attaching the reference bar (4) to the bone (5), and D) at least one adjustable clamp (12) to loosenably fasten a pin (11 ) capable of being set with its tip (26) to a desired point on the surface of the bone (5) 6 Device as claimed in claim 5, characterized in that the adjustable clamp (12) is designed such that the tip (26) is displaceable with three degrees of freedom 7. Device as claimed in claim 6, characterized in that the adjustable clamp (12) comprises a socket 21 , a post (17) and a support (18) whereby the support (18) is slidable in the direction of the central axis (23) on the post (17) and the socket (21 ) is slidable on the reference bar (4) in the direction of the longitudinal axis (10). 8. Device as claimed in claim 7, characterized in that the central axis (23) is arranged perpendicularly to the longitudinal axis (10) and to the axes (13) of the screws (2;3). 9. Device as claimed in claim 7 or 8, characterized in that the support (18) is providing a bore hole (25) for acceptance of the pin (11 ) and with an axis (26) extending perpendicular to the central axis (23) and perpendicular to the longitudinal axis (10). 10. Device as claimed in one of the claims 5 to 9, characterized in that articulated pins (28) are provided. 11. Device as claimed in claim 10, characterized in that the articulated pin (28) is provided with a thread at its end being introduced into the bone. 12. Device as claimed in claim 10 or 11 , characterized in that the articulated pin (28) is provided with a turning knuckle (60) having one degree of freedom. 13. Device as claimed in claim 12, characterized in that the articulated pin (28) is provided with a ball joint. 14. Device as claimed in one of the claims 10 to 13, characterized in that the articulation of the articulated pin (28) is loosenably fastenable. AMENDED CLAIMS [received by the International Bureau on 03 November 2000 (03.11.00); original claims 1 - 14 replaced by new claims 1 -13 (3 pages)] 1. Method for the determination of reduction parameters for the subsequent adjustment of a reduction device in order to reduce the fragments of a fractured bone (5), characterized in that A) the determination of the reduction parameters is performed by means of a comparison of the contour of the corresponding bones (5;27) of interest at the patient's left respective right side of the body; whereby B) the positions of at least three non-collinear points (31 ;32) at one of the bones (5;27) of interest are determined, therewith establishing a three-dimensional coordinate system (35) with respect to the body of the patient; C) the positions of the corresponding points (31 ;32) at the corresponding bone (5;27) of interest and within the coordinate system (35) are determined whereby the determination of the points (31;32) is effected such that the at least three points (32) are situated on the proximal fragment (42) of the fractured bone (5); D) a plane of symmetry (34) is established by means of dividing the connecting vectors between each point (31) and its corresponding point (32) in two parts therewith defining central points of the vectors which determine three points of the plane of symmetry (34) within the coordinate system (35); E) a mirror image (30) of the patient's non-fractured bone (27) is generated symmetrically to the plane of symmetry (34) by means of determining at least three non-collinear points (36) at the non-fractured bone (27) at each section corresponding to a fragment (40;41;42) of the fractured bone (5) and by forming the mirror image (30) by determination of the points (33) that are symmetrical to the points (36) with respect to the plane of symmetry (34); F) the positions of at least three points (39) at each fragment (40;41;42) of the fractured bone (5) and corresponding to the points (36) at the non-fractured bone (27) are determined; and G) the reduction parameters are then determined by comparison of the different positions of the points (39) at the fractured bone (5) with the positions of the points (33) within the mirror image (30). 2. Method as claimed in claim 1 , characterized in that the determination of the position of the at least three points (31) at one of the bones (5;27) and the determination of the position of the identical points (32) at the other bone (5;27) is performed by means of touching the points (31 ;32) on the surface of the bones (5;27) with the tip (26) of a pointer (52) which is provided with at least three markers (53) whose position is determinable within an on-site three-dimensional coordinate system (54) by means of an optical position measurement device (56) and respective data management via a computer (57). 3. Method as claimed in claim 2, characterized in that the points (31 ) at the non- fractured bone (27) and the identical points (32) at the fractured bone (5) are defined by means of fiducial markers (50;51 ) that were pre-operatively implanted. 4. Method as claimed in claim 1 , characterized in that the determination of the position of the at least three points (31 ) at one of the bones (5;27) is performed by means of fastening at least one reference bar (4) through at least two screws (2;3) or pins to the bone (5;27) and determining a third point with an adjustable pin (11) and performing the determination of the position of the identical points (32) at the other bone (5;27) by means of fastening at least one reference bar (4) through at least two screws (2;3) or pins to the other bone (5;27) and determining the third point with an adjustable pin (11 ). 5. Device for the determination of reduction parameters at a fractured bone (5) according to the method according to one of the claims 1 or 4, comprising A) a cylindric or prismatic reference bar (4) having a longitudinal axis (10); B) at least two clamps (9) displaceable on the reference bar (4) in the direction of the longitudinal axis (10) and fastenable to the reference bar (4); C) at least two screws (2;3) or pins with axes (13) loosenable fixable transversely to the reference bar (4) within the clamps (9) whereby the screws (2;3) are screwable into the bone (5) therewith attaching the reference bar (4) to the bone (5); and D) at least one adjustable clamp (12) to loosenably fasten a pin (11 ) capable of being set with its tip (26) to a desired point on the surface of the bone (5), characterized in that E) the adjustable clamp (12) comprises a socket 21 , a post (17) and a support (18) whereby the support (18) is slidable in the direction of the central axis (23) on the post (17) and the socket (21) is slidable on the reference bar (4) in the direction of the longitudinal axis (10). 6. Device as claimed in claim 5, characterized in that the adjustable clamp (12) is designed such that the tip (26) is displaceable with three degrees of freedom. 7. Device as claimed in claim 5 or 6, characterized in that the central axis (23) is arranged perpendicularly to the longitudinal axis (10) and to the axes (13) of the screws (2;3). 8. Device as claimed in one of the claims 5 to 7, characterized in that the support (18) is providing a bore hole (25) for acceptance of the pin (11 ) and with an axis (26) extending perpendicular to the central axis (23) and perpendicular to the longitudinal axis (10). 9. Device as claimed in one of the claims 5 to 8, characterized in that articulated pins (28) are provided. 10. Device as claimed in claim 9, characterized in that the articulated pin (28) is provided with a thread at its end being introduced into the bone. 11. Device as claimed in claim 9 or 10, characterized in that the articulated pin (28) is provided with a turning knuckle (60) having one degree of freedom. 12. Device as claimed in claim 9, characterized in that the articulated pin (28) is provided with a ball joint. 13. Device as claimed in one of the claims 9 to 12, characterized in that the articulation of the articulated pin (28) is loosenably fastenable.

Inventors: HEHLI MARKUS, MITKOVIC MILORAD, PERREN STEPHAN, HEHLI, MARKUS, MITKOVIC, MILORAD, PERREN, STEPHAN
Applicants: HEHLI MARKUS, MITKOVIC MILORAD, PERREN STEPHAN, SYNTHES AG, SYNTHES USA, HEHLI, MARKUS, MITKOVIC, MILORAD, PERREN, STEPHAN, SYNTHES (U.S.A.), SYNTHES AG CHUR
Application year: 1999
Main classification: A61B17
IPC codes: A61B5, A61B17, A61B19, A61F5, G01B5, G01B11, G01B21