(19)
(11)EP 2 481 363 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
10.07.2019 Bulletin 2019/28

(21)Application number: 12164119.5

(22)Date of filing:  23.09.2005
(51)International Patent Classification (IPC): 
A61B 17/17(2006.01)
A61B 17/00(2006.01)

(54)

Coplanar X-ray guided aiming arm for locking of intramedullary nails

Koplanarer röntgengeführter Zielarm zur Arretierung von Marknägeln

Bras de visée à guidage par rayons X coplanaires pour blocage de clous centromédullaires


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

(30)Priority: 23.09.2004 US 947155

(43)Date of publication of application:
01.08.2012 Bulletin 2012/31

(62)Application number of the earlier application in accordance with Art. 76 EPC:
05799921.1 / 1799127

(73)Proprietor: Synthes GmbH
4436 Oberdorf (CH)

(72)Inventors:
  • Fernandez, Alberto
    Montevideo 11500 (UY)
  • Büttler, Markus
    4702 Oensingen (CH)
  • Waelchli, Andreas
    3043 Uettlingen (CH)

(74)Representative: Klunker IP Patentanwälte PartG mbB 
Destouchesstraße 68
80796 München
80796 München (DE)


(56)References cited: : 
WO-A-03/092515
CH-A5- 668 692
US-A- 4 917 111
US-A- 5 766 179
CH-A5- 664 725
US-A- 4 803 976
US-A- 4 976 713
US-B1- 6 371 959
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD OF INVENTION



    [0001] The present invention is directed to aiming arm locking of intramedullary nails, and in particular to X-ray guided aiming arm locking of intramedullary nails.

    BACKGROUND OF THE INVENTION



    [0002] It is well known the use of intramedullary nails to treat bone fractures in tubular bones. A nail is implanted in the medullary canal of the bone across the fracture site in order to retain the bone fragments on the bone nail and to secure the bone fragments from being displaced. The nail has transverse holes and is fixed to the bone by a number of locking screws or fixation bolts which must pass through holes in the nail and into the surrounding bone material. After the nail is inserted into the medullary canal, the distal end of the nail is invisible to the naked eye. Numerous methods and apparatus have been developed to successfully place locking screws across both a fractured bone and an implanted intramedullary nail.

    [0003] Usually nails are locked at both ends, close to the entry point and far away from the entry point. The region of the bone where the nail is implanted is identified as proximal and the opposite end of the intramedullary nail is distal. Nail locking is currently made using either mechanical aiming arms or X-ray guidance.

    [0004] Mechanical aiming instruments, which are fixedly attached to the proximal end of the implanted bone nail, may provide concentric alignment with the proximal screw holes in order to enable reliable drilling such as those disclosed in United States Patent Nos. 5,334,192, 5,766,179, and 6,514,253.

    [0005] An advantage of this mechanical aiming arm is that neither the patient nor the surgeon will be exposed to the X-ray source. However, distal screw holes may not perform satisfactorily due to distortion of the intramedullary nail while being driven into the bone and/or mechanical stress on the aiming arm. Aiming-arm-guided-locking is usually successful for proximal locking since the distortion of the nail when inserted into the bone is negligible for a short length of nail. However, it is usually not successful for distal locking except for very short nails since the distortion of the nail when inserted into the bone is not negligible.

    [0006] Distortion in the implanted intramedullary nail happens in the 3D space and can be analyzed into its main components:
    • Length variation in the axis of the intramedullary nail.
    • Rotational distortion in the axis of the intramedullary nail.
    • Flexion distortion in the plane of the intramedullary nail distal holes
    • Flexion distortion perpendicular to the plane of the distal holes of the intramedullary nail.


    [0007] We can accept, when using non slotted intramedullary nails provided of coplanar distal holes, that the first three mentioned distortions: (1) length distortion in the axis of the nail, (2) rotational distortion in the axis of the nail, and (3) flexion deformity in the plane of the distal screw holes of the nail, are negligible for our task of distal locking. However, flexion distortion in a plane perpendicular to the plane of the distal screw holes of the nail is very important and the distortion of concern when distal locking is the objective.

    [0008] X-ray guidance is what is presently most used for distal locking except for very short nails. The procedure starts by exactly positioning the X-ray beam in the axis of the nail holes, something that is not always straightforward for the X-ray technician. The intramedullary nail will cast a dark, elongate image on the X-ray monitor, while the nail holes will appear as light circles or ovals. In particular, the nail hole will appear as a circle when the X-ray source is positioned such that the X-ray beam is parallel to the axis of the nail hole, something that is a complex 3D procedure.

    [0009] After the nail holes have been located, a drill is used to drill through the bone for insertion of the locking screw. This procedure may be accomplished either with or without the use of an aiming arm guide, wherein said aiming arm guide can be fastened to the bone nail or not.

    [0010] Various aiming guides are already known in the art to be used in conjunction with the X-ray source in order to accurately place the locking bone screws across both a fractured bone and an implanted intramedullary nail, such as those disclosed in United States Patent Nos. 4,803,976, 4,850,344, 6,656,189, 4,667,664, and 4,881,535.

    [0011] All these X-ray guided procedures require the X-ray source positioned such that the X-ray beam is parallel to the axis of the nail hole. This is not always simple, and sometimes not even possible. It may also increase undesirable X-ray exposure to the surgeon, patient and operating room staff, and lengthen the surgical procedure.

    [0012] WO 03/092515 A2 discloses an apparatus for handling an intramedullary nail, in particular for determining the location and orientation of a transverse hole in the implanted intramedullary nail. The apparatus comprises a radiolucent aiming arm having transverse holes. The aiming arm is connected to a handle portion by a hinge to allow angular adjustment of the aiming arm. The aiming arm has radiopaque markers embedded, for example metallic wires. X-ray is used to align the aiming arm with the intramedullary nail.

    [0013] US 4,976,713 discloses an apparatus for aligning a drill guide with a transverse hole in an implanted intramedullary nail. A viewfinder is attached to an aiming arm. The viewfinder is formed from a radiolucent cylinder having four metallic blades embedded such that the viewfinder can be located and oriented by means of x-ray. Once aligned, the viewfinder is replaced by a drill guide having a transverse hole for guiding a drilling tool.

    [0014] Attempts have been made in the past to obtain a successful method for distal locking, which overcome the problems associated with X-ray guided locking. However, most of these systems are cumbersome and require additional bone screw holes in order to exactly assess the position of the hole in the distorted intramedullary nail after implantation into the bone.

    [0015] The present invention relates to a novel apparatus for distal locking that allows the surgeon to target and install bone screws into an intramedullary nail in an accurate, fast and reliable manner.

    SUMMARY OF THE INVENTION



    [0016] The aiming object of the invention is defined in claim 1. Preferred embodiments are defined in the dependent claims.

    [0017] It is therefore an object of the present invention to provide an aiming arm capable of being adjusted to compensate for the intramedullary nail distortion after its insertion into the bone, making use of the information given by a few snap shots of the X-ray image intensifier.

    [0018] Another object of the present invention is to provide a radiolucent aiming arm for distal locking of an intramedullary nail having radiopaque target markers for use in determining when the position of an X-ray source is such that an X-ray beam is coplanar with the aiming arm holes axis.

    [0019] Further, it is an object of the present invention to reduce undesirable X-ray exposure to the surgeon, patient and operating room staff.

    [0020] The present disclosure further provides an easy and straightforward procedure for the X-ray technician and the surgeon and makes distal bone fixation of intramedullary nails simple and fast, thereby addressing one of the most important issues in actual surgery - time shortening.

    [0021] The aiming arm of the present invention overcomes the disadvantages of conventional aiming arms by providing an easily obtainable X-ray guidance for distal locking without requiring that the X-ray beam be coaxial with the nail hole, thus reducing undesirable X-ray exposure to the surgeon, patient and operating room staff.

    [0022] The aiming arm of the invention is capable of being adjusted to compensate for the nail deformation after its insertion into bone, making use of the information given by a few snap shots of the X-ray image intensifier.

    [0023] By fulfilling the objectives mentioned above, the present invention is extremely helpful to the medical care area.

    [0024] The preferred embodiment of the present invention provides an adjustable aiming arm fastened to a bone nail. The aiming arm is constructed of a radiolucent material and has coplanar transverse holes or apertures. The aiming arm has a number of radiopaque target markers to enable the X-ray technician to assess when the position of an X-ray source is such that an X-ray beam is coplanar with the transverse holes of aiming arm. The image shown by a single X-ray snapshot in this position gives the surgeon precise information on the amount of nail distortion after nail insertion into the bone, thereby allowing the surgeon to determine the aiming arm adjustment needed to compensate for the distortion of the intramedullary nail. Once the aiming arm is accurately oriented over the nail hole, so that the aiming arm transverse holes are coaxial with the nail holes, the surrounding bone material can be drilled. After the bone is drilled, locking bone screws are screwed through the protective sleeves previously inserted into the aiming arm transverse holes.

    [0025] Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0026] Preferred features of the present invention are disclosed in the accompanying drawings, wherein similar reference characters denote similar elements throughout the several views, and wherein:

    FIG. 1 is a side view of an aiming arm according to a preferred embodiment of the present invention, wherein the aiming arm is connected to an intramedullary nail.;

    FIG. 2 is a top view of the aiming arm shown in FIG. 1;

    FIG. 3 includes both top and side views of the lower portion of the aiming arm of FIG. 1;

    FIG. 4 is a partial view of a top surface of the distal portion of the aiming arm of FIG. 1 showing the radiopaque markers;

    FIG. 5 is a partial view of the bottom surface of the aiming arm of FIG. 1, opposite the surface shown in FIG. 4; and

    FIG. 6 is a partial view of the properly aligned radiopaque markers of the aiming arm shown in FIG. 1.


    DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS



    [0027] In a preferred embodiment, shown in FIGS. 1-2, the present inventions relates to a radiolucent aiming device 30 for targeting transverse bores in an intramedullary nail 32 in order to distally lock nail 32 in place within a patient's bone. Aiming device 30 includes an aiming arm 34, which is removably and adjustably connected to an upper handle 36 and includes at least one transverse hole 33 for receiving and guiding drilling and fixation elements. Aiming arm 34 is configured to be both rotated with respect to handle 36 about axis 50 and translated with respect to handle 36 along axis 53 in the direction 52. Aiming arm 34 may also be removed from and re-connected to handle 36 for use with either left-hand or right-hand intramedullary nails. Handle 36 is attached to intramedullary nail 32 via nail insertion handle 38, which is releasably mounted to aiming arm handle 36 via a bolt, screw or other connection element having a knurled nut 39.

    [0028] Aiming arm 34 includes a radiolucent lower portion 35 and an upper portion 37, where lower portion 35 is pivotally attached to upper portion 37 via a pin 40 and includes an adjustment knob 42 that actuates a screw mechanism to rotate arm portion 34 about axis 50 in order to adjust the angle of lower aiming arm portion 35 with respect to upper aiming arm portion 37 and handle 36. In a preferred embodiment, axis 50 is parallel to the axis of the transverse holes in the intramedullary nail. Handle 36 also includes a plurality of elongated slots 44 along which the upper portion 37 of aiming arm 34 may be adjustably mounted. A particular rail is selected based upon the orientation of the nail, i.e., right or left, and the size/length of the nail 32. Once mounted along a slot 44 by one or more pins 46, aiming arm 34 may be releasably locked against further translation along the direction 52 by knurled nut 48.

    [0029] As shown best in FIGS. 4 and 5, lower portion 35 of aiming arm 34 includes a set of radiopaque markers on both its top and bottom surfaces, 56, 58, respectively. Top surface 56 includes a plurality of peripheral circles 60 aligned along the two longitudinal edges of top surface 56 and a series of dots 62 along the centerline of top surface 56. In addition, as discussed more fully below, a series of scale markers 64 (in the form of dashes), aid in determining the degree of angular adjustment necessary when the aiming arm 34 is not correctly aligned with the X-ray source. Top surface 56 may also include radiopaque markers 66 indicating the correct orientation of the device for the given installation, i.e., the letters "L" and "R." In a preferred embodiment, circles 60 may have a diameter on the order 5.0 mm and scale markers 64 may have a length on the order of 5.0 mm.

    [0030] As shown in FIG. 5, bottom surface includes its own set of radiopaque markers in the form of two peripheral lines 68 and one median line 70, all of which run parallel to one another. Peripheral lines 68 extend along both longitudinal edges of the bottom surface 58, while median line 70 runs along the centerline of bottom surface 58. Lines 68, 70 may a have a thickness on the order of 1.0-2.0 mm. As shown in FIGS. 2 and 3, in addition to being radiolucent, lower portion 35 of aiming arm 34 may include one or more recessed sections 72 between the top and bottom surfaces 56, 58, and their respective sets of radiopaque markers, such that less solid material lies between the radiopaque markers. This will aid in visualization and alignment of the radiopaque markers under image intensification.

    [0031] In an effort to further describe the features and benefits of the present invention, reference will now be made to a method of using the disclosed aiming device. First, prior to insertion of the intramedullary nail, the nail must be properly aligned with the aiming device of the present invention. Accordingly, nail insertion handle 38 is attached to aiming arm handle 36. Next, aiming arm 34 is connected to an appropriate slot 44, which is selected based upon the nail length/size and the side of the patient requiring implantation, i.e., left or right. Knurled nut 48 is loosely coupled to handle 36 and calibration trocars 41 are used to align the aiming arm holes 33 with the transverse holes in the intramedullary nail and determine the appropriate length of aiming arm 34. Once the aiming arm holes 33 are properly aligned with the nail holes, knurled nut 48 is tightened securely and the calibration trocars are removed from device 30. Following this initial calibration, aiming device 30 is removed from insertion handle 38, and the nail is inserted into the medullary canal of the patient. After insertion, the nail is typically locked proximally using known techniques.

    [0032] With the nail 32 inserted into the patient and proximally locked, aiming device 30 is re-attached to the nail insertion handle 38, with care taken not to adjust the knurled nut 48, which locks the aiming arm 34 against translational movement along slot 44. Next, the image intensification equipment (C-ARM) is moved toward the patient and angled approximately 30-40° to the longitudinal axis of the bone. (This keeps the surgeon out of the radiation beam and helps avoid the contralateral limb.) Next, using the C-ARM, the surgeon verifies that the image of the radiopaque markers of aiming arm 34 is configured for the appropriate side (left or right). If so, the "L" or "R" symbol, shown as 66 in FIG. 3. If necessary, the image may be transposed. While still using the C-ARM, the surgeon then identifies the various radiopaque markers, e.g., peripheral circles 60, dots 62, scale markers 64, and lines 68, 70. The C-ARM beam is then adjusted in order to align the dots 62 so that they overlay the median line 70 and/or so that the relationship between the peripheral circles 60 and peripheral lines 68 is symmetrical (as shown in FIGS. 5 & 6). Therefore, if the dots 62 and circles 60 are above lines 68 and 70, the C-ARM should be rotated down, and if the dots 62 and circles 60 are below the lines 68, 70, then the C-ARM should be rotated up. In a preferred embodiment, scale markers 64 are configured such that each graduation of the scale represents 2° of rotation. Therefore, the surgeon can use the scale markers 64 to determine the amount the C-ARM needs to be rotated in order to properly align the beam with the plane of the aiming arm holes 33. As shown in FIG. 6, when the center dots 62 overlay the median line 70, and the peripheral circles 60 lie symmetrically with respect to the peripheral lines 68, aiming arm 34 has been properly aligned with the C-ARM. If circles 60 are not symmetrically positioned with respect to the peripheral lines 68, the C-ARM still requires adjustment.

    [0033] Once aiming arm 34 is properly aligned with the C-ARM, the surgeon can visualize the nail and determine if any deflection in the anterior-posterior plane, i.e., in a direction perpendicular to the axis of the nail holes, has occurred. If so, the lower portion 35 of aiming arm 34 can be adjusted to re-align the aiming arm holes 33 with the nail holes. As discussed above, turning of adjustment knob 42 rotates the lower portion 35 of aiming arm 34 with respect to the handle 36 to accomplish this alignment and compensate for the anterior-posterior nail deflection. After adjusting the angle of the aiming arm 34, a final check should be made to ensure that the radiopaque markers are still in proper alignment. If not, the alignment steps described above should be repeated. Once aligned, a sleeve/trocar assembly is inserted through the aiming arm holes 33, and the radiopaque markers are checked once again to confirm alignment prior to drilling and insertion of locking elements.

    [0034] While I have illustrated and described a preferred embodiment of the invention, it will be understood that those skilled in the art will thereby be enabled to devise variations and modifications without departing from the scope of this invention, which is defined only by the following claims.


    Claims

    1. An aiming device (30) for determining the location and orientation of a transverse hole in an implanted intramedullary nail (32) comprising:

    a handle portion (36) attachable to the proximal end of an intramedullary nail (32); and

    an aiming arm (34) formed of a radiolucent material, the aiming arm (34) having at least one transverse hole (33), the transverse hole (33) running from a first surface (56) to a second surface (58), the aiming arm (34) having at least one radiopaque marker (60, 62, 64, 66, 68, 70);

    wherein the aiming arm (34) is adjustably rotatable with respect to the handle portion (36),

    characterized in that the aiming arm (34) is configured and dimensioned for removable attachment to the handle portion (36), and is adjustably translatable with respect to the handle portion (36), and

    both the first and second surfaces (56, 58) have at least one radiopaque marker (60, 62, 64, 66, 68, 70) for use in determining when the position of an X-ray source is such that an X-ray beam is coplanar with the axis of the transverse hole (33).


     
    2. The aiming device of claim 1, wherein the transverse hole (33) in the aiming arm (34) defines a first axis, and the aiming arm (34) is adjustably rotatable about a second axis (50) parallel to the first axis of the transverse hole (33).
     
    3. The aiming device of claim 2, wherein the aiming arm (34) includes a radiolucent first portion (35) and a second portion (37), wherein first portion (35) is pivotally attached to the second portion (37) via a pin (40) and includes an adjustment knob (42) for actuating a screw mechanism to rotate the aiming arm (34) about the second axis (50) in order to adjust the angle of the first portion (35) with respect to the second portion (37) and the handle (36).
     
    4. The aiming device of any one of claims 1 to 3, wherein the handle portion (36) includes at least one longitudinal slot (44) configured and dimensioned to permit translation of the aiming arm (34) with respect to the handle portion (36).
     
    5. The aiming device of claim 4, wherein, once mounted along the longitudinal slot (44) by one or more pins (46), the aiming arm (34) is releasably lockable against further translation by a knurled nut (48).
     
    6. The aiming device of any one of claims 1 to 5, wherein the radiopaque marker (60) on the first surface (56) is a circle (60).
     
    7. The aiming device of any one of claims 1 to 6, wherein the radiopaque marker (64) on the first surface (56) is scaled to indicate an adjustment value to a user.
     
    8. The aiming device of any one of claims 1 to 7, wherein the radiopaque markers (60, 62, 64, 66, 68, 70) on the first and second surfaces (56, 58) indicate the alignment of an X-ray source to obtain an X-ray beam coplanar with a central axis of the at least one transverse hole (33) of the aiming arm (34).
     
    9. The radiolucent aiming arm of any one of claims 1 to 8, wherein the intramedullary nail (32) has a longitudinal axis, and alignment of the radiopaque markers (60, 62, 64, 66, 68, 70) indicates that an X-ray beam is coplanar with a plane defined by the central axis of the aiming arm transverse hole (33) and the longitudinal axis of the intramedullary nail (32), before the nail (32) was inserted into the bone.
     
    10. The aiming device of any one of claims 1 to 9, wherein the radiopaque marker (60, 62, 64, 66) on the first surface (56) is different than the radiopaque marker (68, 70) on the second surface (58).
     
    11. The aiming device of claim 10, wherein the radiopaque marker (60, 62, 64, 66) on the first surface (56) comprises at least three circles (60) and the radiopaque marker (68, 70) on the second surface (58) comprises at least one line (68, 70).
     
    12. The aiming device of any one of claims 1 to 11, wherein the radiopaque marker (60, 62, 64, 66) on the first surface (56) includes a plurality of peripheral circles (60) aligned along two longitudinal edges of the first surface (56) and a series of dots (62) along a centerline of the first surface (56).
     
    13. The aiming device of any one of claims 1 to 12, wherein the radiopaque marker (68, 70) on the second surface (58) includes two peripheral lines (68) and one median line (70), all of which run parallel to one another, the peripheral lines (68) extending along both longitudinal edges of the second surface (58), the median line (70) running along a centerline of the second surface (58).
     
    14. The aiming device of any one of claims 1 to 13, further comprising at least one recessed volume (72) formed between the first and second surfaces (56, 58) to minimize the amount of material between the radiopaque markers (60, 62, 64, 66, 68, 70).
     


    Ansprüche

    1. Zielvorrichtung (30) zum Bestimmen von Ort und Orientierung eines Querlochs in einem implantierten intramedullären Nagel (32), umfassend:

    einen an dem proximalen Ende eines intramedullären Nagels (32) anbringbaren Handgriffabschnitt (36); und

    einen Zielarm (34) aus einem strahlungsdurchlässigen Werkstoff, mit mindestens einem Querloch (33), welches von einer ersten Oberfläche (56) zu einer zweiten Oberfläche (58) verläuft, wobei der Zielarm (34) mindestens eine strahlungsundurchlässige Markierung (60, 62, 64, 66, 68, 70) aufweist;

    wobei der Zielarm (34) in Bezug auf den Handgriff (36) drehbar einstellbar ist,

    dadurch gekennzeichnet, dass der Zielarm (34) konfiguriert und dimensioniert ist für eine abnehmbare Anbringung des Handgriffs (36), und in Bezug auf den Handgriff (36) einstellbar versetzbar ist, und

    sowohl die erste als auch die zweite Oberfläche (56, 58) mindestens eine strahlungsundurchlässige Markierung (60, 62, 64, 66, 68, 70) aufweist zum Bestimmen, wann die Position einer Röntgenstrahlquelle derart ist, dass ein Röntgenstrahl koplanar mit der Achse des Querlochs (33) ist.


     
    2. Zielvorrichtung nach Anspruch 1, bei der das Querloch (33) in dem Zielarm (34) eine erste Achse definiert, und der Zielarm (34) um eine zweite Achse (50) parallel zu der ersten Achse des Querlochs (33) drehbar einstellbar ist.
     
    3. Zielvorrichtung nach Anspruch 2, bei der der Zielarm (34) einen strahlungsdurchlässigen ersten Abschnitt (35) und einen zweiten Abschnitt (37) enthält, wobei der erste Abschnitt (35) schwenkbar zu dem zweiten Abschnitt (37) über einem Zapfen (40) angebracht ist und einen Einstellknopf (42) zum Betätigen eines Schraubenmechanismus' zum Drehen des Zielarms (34) um die zweite Achse (50) enthält, um den Winkel des ersten Abschnitts (35) bezüglich des zweiten Abschnitts (37) und des Handgriffs (36) einzustellen.
     
    4. Zielvorrichtung nach einem der Ansprüche 1 bis 3, bei der der Handgriff (36) mindestens einen Längsschlitz (44) enthält, konfiguriert und dimensioniert zum Ermöglichen einer Translation des Zielarms (34) bezüglich des Handgriffs (36).
     
    5. Zielvorrichtung nach Anspruch 4, bei der der entlang dem Längsschlitz (44) durch einen oder mehrere Zapfen (46) angebrachte Zielarm (34) gegen eine weitere Translation durch eine Rändelmutter (48) lösbar sperrbar ist.
     
    6. Zielvorrichtung nach einem der Ansprüche 1 bis 5, bei der die strahlungsundurchlässige Markierung (60) an der ersten Oberfläche (56) ein Kreis (60) ist.
     
    7. Zielvorrichtung nach einem der Ansprüche 1 bis 6, bei der die strahlungsundurchlässige Markierung (64) auf der ersten Oberfläche (56) skaliert ist, um einen Einstellwert für einen Benutzer anzuzeigen.
     
    8. Zielvorrichtung nach einem der Ansprüche 1 bis 7, bei der die strahlungsundurchlässigen Markierungen (60, 62, 64, 66, 68, 70) auf der ersten und der zweiten Oberfläche (56, 58) die Ausrichtung einer Röntgenstrahlquelle angeben, um einen Röntgenstrahl koplanar mit einer Mittelachse des mindestens einem Querlochs (33) des Zielarms (34) zu erhalten.
     
    9. Strahlungsdurchlässiger Zielarm nach einem der Ansprüche 1 bis 8, bei dem der intramedulläre Nagel (32) eine Längsachse aufweist und die Ausrichtung der strahlungsundurchlässigen Markierungen (60, 62, 64, 66, 68, 70) angibt, dass ein Röntgenstrahl koplanar ist mit einer Ebene, die definiert ist durch die Mittelachse des Zielarm-Querlochs (33) und die Längsachse des intramedullären Nagels (32), bevor der Nagel (32) in den Knochen eingeführt wurde.
     
    10. Zielvorrichtung nach einem der Ansprüche 1 bis 9, bei der die strahlungsundurchlässige Markierung (60, 62, 64, 66, 68, 70) auf der ersten Oberfläche (56) verschieden ist von der strahlungsundurchlässigen Markierung (68, 70) auf der zweiten Oberfläche (58).
     
    11. Zielvorrichtung nach Anspruch 10, bei der die strahlungsundurchlässige Markierung (60, 62, 64, 66) auf der ersten Oberfläche (56) mindestens drei Kreise (60) aufweist, und die strahlungsundurchlässige Markierung (68, 70) auf der zweiten Oberfläche (58) mindestens eine Linie (68, 70) aufweist.
     
    12. Zielvorrichtung nach einem der Ansprüche 1 bis 11, bei der die strahlungsundurchlässige Markierung (60, 62, 64, 66) auf der ersten Oberfläche (56) mehrere Umfangskreise (60) enthält, ausgerichtet entlang zweier Längskanten der ersten Oberfläche (56), ferner einer Reihe von Punkten (62) entlang einer Mittellinie der ersten Oberfläche (56).
     
    13. Zielvorrichtung nach einem der Ansprüche 1 bis 12, bei der die strahlungsundurchlässig Markierung (68, 70) auf der zweiten Oberfläche (58) zwei Umfangslinien (68) und eine Medianlinie (70) enthält, die sämtlich parallel zueinander verlaufen, wobei die Umfangslinien (68) sich entlang der beiden Längskanten der zweiten Oberfläche (58) erstrecken, und die Medianlinie (70) entlang einer Mittellinie der zweiten Oberfläche (58) verläuft.
     
    14. Zielvorrichtung nach einem der Ansprüche 1 bis 13 weiterhin umfassend mindestens ein Vertiefungsvolumen (72), das zwischen der ersten und der zweiten Oberfläche (56, 58) ausgeformt ist, um die Werkstoffmenge zwischen den strahlungsundurchlässigen Markierungen (60, 62, 64, 66, 68, 70) zu minimieren.
     


    Revendications

    1. Dispositif de visée (30) destiné à déterminer l'emplacement et l'orientation d'un trou transversal dans un clou intramédullaire implanté (32), comprenant :

    une portion formant poignée (36) pouvant être fixée sur l'extrémité proximale d'un clou intramédullaire (32), et

    un bras de visée (34) formé d'un matériau radiotransparent, le bras de visée (34) présentant au moins un trou transversal (33), le trou transversal (33) allant d'une première surface (56) à une seconde surface (58), le bras de visée (34) présentant au moins un marqueur radio-opaque (60, 62, 64, 66, 68, 70) ;

    dans lequel le bras de visée (34) peut être tourné de manière réglable par rapport à la portion formant poignée (36),

    caractérisé en ce que le bras de visée (34) est configuré et dimensionné pour une fixation amovible sur la portion formant poignée (36), et peut subir une translation de manière réglable par rapport à la portion formant poignée (36), et

    les première et seconde surfaces (56, 58) présentent toutes deux au moins un marqueur radio-opaque (60, 62, 64, 66, 68, 70) destiné à être utilisé pour déterminer lorsque la position d'une source de rayons X est telle qu'un faisceau de rayons X est coplanaire avec l'axe du trou transversal (33).


     
    2. Dispositif de visée selon la revendication 1, dans lequel le trou transversal (33) dans le bras de visée (34) définit un premier axe, et le bras de visée (34) peut tourner de manière réglable autour d'un second axe (50) parallèle au premier axe du trou transversal (33).
     
    3. Dispositif de visée selon la revendication 2, dans lequel le bras de visée (34) inclut une première portion radiotransparente (35) et une seconde portion (37), dans lequel la première portion (35) est fixée par pivotement sur la seconde portion (37) via une broche (40), et inclut un bouton de réglage (42) pour actionner un mécanisme à vis et faire tourner le bras de visée (34) autour du second axe (50) afin de régler l'angle de la première portion (35) par rapport à la seconde portion (37) et la poignée (36).
     
    4. Dispositif de visée selon l'une quelconque des revendications 1 à 3, dans lequel la portion formant poignée (36) inclut au moins une fente longitudinale (44) configurée et dimensionnée pour permettre une translation du bras de visée (34) par rapport à la portion formant poignée (36).
     
    5. Dispositif de visée selon la revendication 4, dans lequel après montage le long de la fente longitudinale (44) par une ou plusieurs broches (46), le bras de visée (34) peut être verrouillé, d'une manière permettant une libération, contre une translation supplémentaire, par un écrou moleté (48).
     
    6. Dispositif de visée selon l'une quelconque des revendications 1 à 5, dans lequel le marqueur radio-opaque (60) sur la première surface (56) est un cercle (60).
     
    7. Dispositif de visée selon l'une quelconque des revendications 1 à 6, dans lequel le marqueur radio-opaque (64) sur la première surface (56) est scellé pour indiquer une valeur de réglage à un utilisateur.
     
    8. Dispositif de visée selon l'une quelconque des revendications 1 à 7, dans lequel les marqueurs radio-opaques (60, 62, 64, 66, 68, 70) sur les première et seconde surfaces (56, 58) indiquent l'alignement d'une source de rayons X afin d'obtenir un faisceau de rayons X coplanaire avec un axe central du au moins un trou transversal (33) du bras de visée (34).
     
    9. Bras de visée radiotransparent selon l'une quelconque des revendications 1 à 8, dans lequel le clou intramédullaire (32) présente un axe longitudinal, et l'alignement des marqueurs radio-opaques (60, 62, 64, 66, 68, 70) indique qu'un faisceau de rayons X est coplanaire avec un plan défini par l'axe central du trou transversal de bras de visée (33) et l'axe longitudinal du clou intramédullaire (32), avant introduction du clou (32) dans l'os.
     
    10. Dispositif de visée selon l'une quelconque des revendications 1 à 9, dans lequel le marqueur radio-opaque (60, 62, 64, 66) sur la première surface (56) est différent du marqueur radio-opaque (68, 70) sur la seconde surface (58).
     
    11. Dispositif de visée selon la revendication 10, dans lequel le marqueur radio-opaque (60, 62, 64, 66) sur la première surface (56) comprend au moins trois cercles (60), et le marqueur radio-opaque (68, 70) sur la seconde surface (58) comprend au moins une ligne (68, 70).
     
    12. Dispositif de visée selon l'une quelconque des revendications 1 à 11, dans lequel le marqueur radio-opaque (60, 62, 64, 66) sur la première surface (56) inclut une pluralité de cercles périphériques (60) alignés le long de deux bords longitudinaux de la première surface (56) et une série de points (62) le long d'une ligne centrale de la première surface (56).
     
    13. Dispositif de visée selon l'une quelconque des revendications 1 à 12, dans lequel le marqueur radio-opaque (68, 70) sur la seconde surface (58) inclut deux lignes périphériques (68) et une ligne médiane (70), l'ensemble desquelles sont parallèles les unes aux autres, les lignes périphériques (68) s'étendant le long des deux bords longitudinaux de la seconde surface (58), et la ligne médiane (70) longeant une ligne centrale de la seconde surface (58).
     
    14. Dispositif de visée selon l'une quelconque des revendications 1 à 13, comprenant en outre au moins un volume en retrait (72) formé entre les première et seconde surfaces (56, 58) afin de minimiser la quantité de matière entre les marqueurs radio-opaques (60, 62, 64, 66, 68, 70).
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description