FR2859904A1 - Screw or pin type osteosynthesis device for excessive osseous inter-fragmentary mobility stabilization/prevention, has wedging unit and groove extending from jamming of screw or pin in osseous material to rotatably lock screw or pin - Google Patents

Abstract

The device has a wedging unit (2) and a groove (8) for anchoring a screw (1) or a pin in an osseous material (15). The unit and the groove, implemented after screwing a peripheral thread (5), are associated with the screw or the pin. The unit and the groove extend from the jamming of the screw or the pin in the material to rotatably lock the screw or pin.

Description

The present invention relates to the general field of surgical equipment,

  and in particular the field of devices intended for osteosynthesis techniques.

  The bone consolidation of certain fractures requires the assembly of osteosynthesis equipment or devices on the various bone fragments, to stabilize and prevent excessive interfragmentary mobility.

  Practitioners then use, in most cases, osteosynthesis devices mounted by screwing on the bone fragments, such as screws, pins or plates screwed, so as to apply a determined compression and adapted to the bone.

  However, the corresponding osteosynthesis devices are not entirely satisfactory because they rarely make it possible to preserve, over time, the initial compression characteristics applied by the practitioner, because of recoil phenomena of the screws or pins used.

  The present invention aims to remedy these drawbacks by proposing an improvement to osteosynthesis devices comprising a threaded portion, screw or spindle type, which allows a simple and fast way to maintain over time the compression applied by the practitioner during assembly of the device, and this in particular by largely limiting the conventional phenomena of unscrewing.

  The osteosynthesis device according to the invention is in the form of a screw or a spindle which is provided with a threaded part enabling it to be screwed into the bone material of reception and which is or is not associated with a plate osteosynthesis.

  This device is characterized in that it comprises additional structural means for anchoring said screw or said pin in the receiving bone material, adapted to be implemented after the screwing of said threaded portion. These anchoring means, once implemented, are associated with said screw or said pin and they extend, for at least part of their structure, out of the bulk of said screw or said pin, in the bone material receiving.

  These anchoring means make it possible to lock the threaded element in rotation in order to prevent any phenomenon of unscrewing and thus to maintain the compression of the device either directly on the bone or on the possibly associated osteosynthesis plate.

  Preferably, the anchoring structural means in question are in the form of at least one key or pin, adapted to be positioned by insertion into the bone material.

  According to a first possible embodiment, the osteosynthesis device comprises a screw or a spindle provided with at least one housing adapted to receive, after screwing onto the bone material, a structural element reported in the form of a pin or key; the corresponding structural element, positioned in said housing, then extends in part out of the bulk of said screw or said pin, driven or anchored in the receiving bone material, in a manner adapted to prevent unscrewing of the part screwed.

  According to a first disposition of this embodiment, the osteosynthesis device comprises a screw or a spindle provided with at least one through-housing adapted to cooperate with a structural element of pin or key type. When this particular arrangement is adapted to a screw consisting of a head extended axially by a central body provided on its periphery with a thread, it may be envisaged to arrange at least one through-housing extending diagonally in said head, and possibly also in the body of the screw.

  According to another arrangement of this embodiment, the osteosynthesis device comprises a screw consisting of a head extended axially by a central body provided on its periphery with a thread, and this screw comprises at least one groove, arranged in said head and optionally extending into the thread, which is intended to receive a key-type insert adapted to sink and anchor in the bone material receiving, after screwing the screw body.

  Preferably, the groove formed in the head, and where appropriate in the screw thread, extends parallel to the longitudinal axis of the screw.

  According to yet another particular embodiment of this embodiment, the screw comprises at least two grooves which are each intended to receive a key-type element; the keys in question are connected by a connecting structure intended to abut against the head of the screw. Preferably, the junction structure is embedded in a complementary slot in the head of the screw.

  Still according to a particular arrangement of this embodiment, the osteosynthesis device is in the form of a pin in the thread of which is arranged at least one groove adapted to receive a key-type insert.

  According to a second embodiment of the invention, the osteosynthesis device comprises a screw whose head incorporates at least one part intended to be deformed, after said screw has been positioned in the bone material of reception, so that said deformable portion has the possibility of sinking and anchoring in said bone material.

  However, the invention will be further illustrated, without being limited in any way, by the following description of various possible embodiments of the invention, given solely as an indication, and represented in the appended drawings in which: FIG. 1 is a general view of perspective of an osteosynthesis device according to the invention which is in the form of a screw cooperating with a keying element; Figure 2 shows the screw of the device of Figure 1, screwed into a bone material shown in section, with the keying element not yet implemented; - Figure 3 still shows the screw of the device of Figure 1 mounted in the bone material, here immobilized in rotation by the keying element; - Figures 4 and 5 still show the device of Figure 1, respectively before and after introduction of the keying element, here associated with an osteosynthesis plate; FIGS. 6 to 13 illustrate other possible embodiments of osteosynthesis devices according to the invention comprising means of the key or pin type, illustrated each time before and after implementation. In particular: FIGS. 6 and 7 represent a screw-type device of which only the head is provided with a slot in the form of a notch adapted to receive a complementary locking key; - Figures 8 and 9 still show a screw-type device, here comprising a through housing, extending diagonally in the head of the screw, for receiving a locking pin; - Figures 10 and 11 further illustrate an alternative form of an osteosynthesis device according to the invention, in the form of screws, the head comprises a deformable element for anchoring in the bone material receiving; - Figures 12 and 13 show a pin-type osteosynthesis device, the threaded portion is provided with a groove-shaped housing adapted to receive an immobilizing key.

  The osteosynthesis device illustrated in FIG. 1 comprises an osteosynthesis screw 1 of conventional general shape intended to cooperate with a keying element 2, as developed later; this osteosynthesis device 1, 2 consists of a biocompatible material, well known to those skilled in the art.

  The corresponding screw 1 consists of a head 3 extended axially by a body 4 provided with a peripheral thread 5.

  The head of the screw 3 is provided with a central recess 6, with a polygonal hexagonal section, which is adapted to receive the end of a tool (not shown), allowing the screw 1 to be mounted on the bone by the practitioner.

  Note that this screw head 3 has a diametrical slot 7, extended orthogonally at each of its ends by a groove 8. The two grooves 8 corresponding are arranged vis-à-vis, on either side of the body 4 of the screw 1 and parallel to its longitudinal axis 1 '; they extend in the material of said screw head 3 and in the thread 5 of the body 4.

  The two longitudinal grooves 8 and the diametrical slot 7 together constitute a housing 9 adapted to receive the keying element 2.

  The corresponding keying element 2 has meanwhile a monobloc structure in the general shape of U flattened. It consists of a central portion 10 forming the junction between two parallel side portions 11 each forming a key; the free end 12 of these lateral parts 11 is bevelled so as to facilitate the insertion into the bone, as developed subsequently.

  For optimum embedment and positioning of the keying element 2 in the housing 9, the thickness of said keying element corresponds, with play, to the width of the housing 9.

  In the illustrated embodiment, the width of the keying element 2 substantially corresponds to the diameter of the outer casing of the upper part of the thread 5, so that this keying element 2 is adapted to fit fully into the wall. overall size of the screw.

  In an application of direct compression of the screw on a receiving bone material (FIGS. 2 and 3), the screw 1 is first conventionally screwed into the bone material 15 so as to exert an appropriate compression on the bone (Figure 2).

  Once the screw 1 correctly positioned, the practitioner reports the keying element 2 in the housing 9, in accordance with the representation of FIG. 3.

  For this, the surgeon positions the lateral portions 11 of the keying element 2 in the plane passing through the longitudinal grooves 8, and he then drives these lateral portions 11 into the bone material 15, so that they position themselves within these grooves 8. This depression is facilitated by the bevel of the free ends 12. The keying element 2 is correctly implemented when the joining portion 10 fits completely into the diametrical slot 7 of the screw 1 ( Figure 3).

  The positioning of the keying element 2 is made by force, by means of any suitable tool, for example a mini-impactor.

  The two keys 11 of the keying element 2, once implemented, are engaged with the screw 1 since part of their structure extends in the size of this screw. On the other hand, another part of their structure extends outside this space, between the turns of the screw thread 5, which allows the anchoring of the screw 1 on the bone and its locking in rotation.

  As illustrated in Figure 3, it is understood that the keying element 2 is used to immobilize in rotation the screw 1 in the bone material receiving 15, this according to the desired compression and applied by the practitioner. Any possibility of unscrewing the screw 1 is prevented, or even greatly limited, which allows to retain over time the compression characteristics initially applied.

  The screw 1 of the osteosynthesis device according to the invention may consist of a conventional osteosynthesis screw in which the housing 9 is made for example by a milling operation or any other technique.

  In the embodiment illustrated in FIGS. 1 to 3, the keying element 2 is adapted to fit completely into the overall bulk of the screw 1, and in particular in the screw head 3. consider the implementation of this osteosynthesis device in combination with an osteosynthesis plate, as illustrated in Figures 4 and 5.

  The corresponding osteosynthesis plate 16 is of the conventional type, here in the general shape of dihedron. It consists of a biocompatible material, such as stainless steel for example. In the illustrated embodiment, the plate 16 is provided with three through holes 17, each adapted to receive an osteosynthesis device 1, 2.

  As illustrated in Figure 4, the screws 1 are conventionally mounted in the bone material 15 through the orifices 17 of the plate 16. The lower face of the head 3 of each of the screws 1 abuts against the upper face of the plate 16 to apply the desired compression.

  Once the keying element 2 has been put in place (FIG. 5), the screw 1 is locked in rotation, which makes it possible, in time, to maintain the compression characteristics initially applied, in a manner similar to that described in FIG. relationship with Figures 1 to 3.

  As has been seen previously, the dimensional characteristics of the keying element 2, and the receiving grooves 8, are adapted so as not to hinder the positioning of the osteosynthesis device in the orifices 17 of the plate 16, while by optimizing the anchoring of the keying element 2 in the bone material.

  For this purpose, the distance between the outer edges of the side portions 11 is less than or equal (within the clearance) to the diameter of the orifices 17. Preferably, this distance corresponds to the clearance close to the diameter of said orifices 17 to optimize the anchoring in the bone material.

  Note that the osteosynthesis plate 16 does not require any particular structural feature to receive the osteosynthesis device 1, 2 according to the invention.

  Alternative embodiments of osteosynthesis devices according to the invention are illustrated in FIGS. 6 to 9.

  In these various figures, there is a screw 1 consisting of a head 3 extended by a body 4 provided with a peripheral thread 5. These screws 1 each still comprise a particular housing adapted to receive a shaped anchoring structure. key or pin.

  The osteosynthesis device illustrated in Figures 6 and 7 has a screw 1 whose head 3 is provided with a housing 20 in the form of a notch. This housing 20 allows the positioning of a key 21 having a generally parallelepipedal shape, one end 22 is tapered. This key 21 has a conformation similar to that of one of the lateral elements 11 of the keying member 2 illustrated in FIGS. 1 to 5. The key 21 has a thickness corresponding, with the clearance, to the width of the notch 20 , to ensure effective stalling.

  The recessing of the key 21 in the housing 20 is illustrated in greater detail in FIG. 7. It can be seen that the key 21 then extends parallel to the longitudinal axis 1 'of the screw 1, and is positioned in contact with the outer peripheral edge of the thread 5, or slightly away from said thread 5.

  When the screw 1 is mounted on the bone material receiving, the key 21 is guided by the housing 20 during its insertion into the bone; the key 21 is thus anchored in the bone material and locks the screw 1 in rotation.

  According to one possible variant of embodiment, several housings 20 can be arranged on the periphery of the screw head 3, each housing 20 then being able to receive a locking member 21.

  The osteosynthesis device illustrated in FIGS. 8 and 9 comprises, for its part, a screw 1 provided with a housing 23 in the form of a through orifice, which extends obliquely from the screw head 3 to the end upper body of screws 4.

  The corresponding housing 23 is adapted to receive a pin or pin 24 of generally cylindrical shape. The outer diameter of the pin 24 corresponds, with the clearance, to the inside diameter of the housing 23.

  The key or pin 24 is embedded in the housing 23 when the screw 1 is mounted on the bone material; it is then forced into the bone so as to ensure its fixation and prevent any possibility of subsequent rotation of the screw. Once the pin 24 in the active position, part of its structure extends within the housing 23, in the size of the screw 1, and another part of its structure extends outside the bulk of said screw, implanted in the bone material. One end of the pin is tapered or tip-shaped to facilitate its insertion into the bone material.

  Figures 10 and 11 further illustrate an alternative embodiment of an osteosynthesis device according to the present invention.

  The screw 1 is again constituted by a head 3 extended by a body 4 provided with a thread 5. It is noted that the screw head 3 comprises a monoblock element 25, deformable, constituting the anchoring structure in the bone . This deformable element 25 can be obtained by means of two parallel cuts made in the screw head 3. These two parallel cuts laterally delimit said deformable element 25, which is connected to the screw head 3 only by a fold line 26.

  If necessary, the thickness of the deformable monobloc element 25 may be decreased, for example by milling, to facilitate its movement around said fold line 26.

  After placing the screw 1 in the receiving material, the practitioner can deform the one-piece element 25 so as to push it into the bone support. As in the context of the embodiments described above, the corresponding anchor makes it possible to immobilize in rotation the fitted screw, to prevent any possibility of unscrewing.

  The osteosynthesis device according to the invention may also be in the form of a pin, as illustrated in FIGS. 12 and 13.

  The corresponding pin 27 has a conventional general conformation with a lower section 28 in the form of a nail, the free end 29 is pointed to facilitate the insertion into the bone material. This pin 27 further comprises a threaded upper section 30 ensuring the finalization of the assembly by screwing; this threaded portion 30 is normally extended by an upper section (not shown) for mounting the spindle by means of a suitable tool. When the assembly is completed, this upper portion protrudes from the receiving bone, and is then cut at the junction with the threaded portion 30. The sectioning in question is facilitated by the presence of a pre-cut area.

  Similarly to the embodiments described above in relation to FIGS. 1 to 9, it will be noted that the pin 27 is associated with anchoring means which are in the form of a key 31 intended to be positioned in a dwelling 32.

  The corresponding housing 32 consists of a groove which extends parallel to the axis 27 'of the spindle, over the entire length of the threaded portion 30, directly into the thread 33. The key 31 is similar to that illustrated in connection with FIG. Figures 6 and 7 described above; it is in the general form of a small elongate parallelepiped, provided with a beveled end 34.

  In practice, the spindle 27 is mounted on the bone material receiving nailing the lower section 28 and screwing the threaded portion 30. Once this pin is properly positioned, the practitioner can cut the upper section (not shown) so as to obtain the The keying member 31 is then attached to the housing 32 by insertion into the bone (not shown) in such a way as to obtain the desired rotational locking (FIG. 13).

  In the illustrated embodiment, the width of the key 31 substantially corresponds to the thickness of the thread 33, but it is understood that this width could be greater, the key 31 then overflowing the overall size of the spindle.

Claims (12)

- CLAIMS -   1.- Osteosynthesis device of the screw or spindle type, associated or not with an osteosynthesis plate, which screw (1) or which pin (27) has a threaded portion (5, 30) allowing it to be screwed into a bone material receiving device (15), characterized in that it comprises additional structural means (2, 8; 20, 21; 23, 24; 25; 31, 32) for anchoring said screw (1) or said spindle ( 27) in the bone receiving material (15), which anchoring means (2, 8; 20, 21; 23, 24; 25; 31, 32), implemented after the screwing of said threaded portion (5, 30), are associated with said screw (1) or said pin (27) and extend, for at least part of their structure, out of the bulk of the screw (1) or the pin (27). in the bone material (15), this suitably for rotationally locking said screw (1) or said pin (25) in order to prevent any loosening phenomenon and thus maintain the compression of said device on the bone, and if necessary on the osteosynthesis plate.   2. An osteosynthesis device according to claim 1, characterized in that said structural anchoring means comprise at least one key or a pin (2, 21, 24, 25, 31) adapted to be positioned by embedding in the material. bony.   3.- osteosynthesis device according to claim 2, characterized in that it comprises a screw (1) or a pin (27) provided with at least one housing (8, 20, 23, 32) adapted to receive, after screwing onto the bone material (15), a pin-shaped or key-shaped structural element (2, 21, 24, 31), which structural element (2, 21, 24, 31) is positioned in said housing (8, 20, 23, 32) is adapted to extend in part out of the bulk of said screw (1) or said pin (27) into said bone receiving material (15).   4.- osteosynthesis device according to claim 3, characterized in that it comprises a screw (1) or a pin (27) provided with at least one through housing (23), which housing (23) is shaped to receiving a structural element (24) of the pin or key type intended to extend partly out of the bulk of the screw (1) or the pin (27) so as to anchor itself in the bone material of reception ( 15).   5.- osteosynthesis device according to claim 4, characterized in that it comprises a screw (1) consisting of a head (3) extended axially by a central body (4) provided on its periphery with a thread ( 5), which screw (1) is provided with at least one through-housing (23) arranged obliquely in said head (3), and possibly also in the body of the screw (4).   6.- osteosynthesis device according to claim 3, characterized in that it comprises a screw (1) consisting of a head (3) extended axially by a central body (4) provided on its periphery with a thread ( 5), which screw (1) has at least one groove (20), arranged in said screw head (3), which groove (20) is intended to receive, after the mounting of said screw (1), an insert Key type (21) part of whose structure is intended to extend out of the bulk of the screw (1) so as to penetrate into the bone material receiving (15).   7.- osteosynthesis device according to claim 3, characterized in that it comprises a screw (1) consisting of a head (3) extended axially by a central body (4) provided on its periphery with a thread ( 5), which screw (1) comprises at least one groove (8), arranged in said screw head (3) and extending at said thread (5), which groove (8) is intended to receive, after mounting of said screw (1), an insert (2) key-type part of which is intended to extend out of the bulk of the screw (1) so as to penetrate into the bone material receiving (15).   8.- osteosynthesis device according to any one of claims 6 or 7, characterized in that it comprises a screw (1) provided with at least one groove (8, 20) arranged in its head (3), and where appropriate in its thread (5), which groove (8, 20) extends parallel to the longitudinal axis (1 ') of said screw (1).   9.- osteosynthesis device according to any one of claims 6 to 8, characterized in that it comprises at least two grooves (8, 20) which are each intended to receive a member (11) key-type, which elements (11) are connected by a connecting structure (10) intended to abut against the head of the screw (3).   10. An osteosynthesis device according to claim 9, characterized in that the junction structure (10) is intended to be embedded in a complementary slot (7) arranged in the head of the screw (3).   11. An osteosynthesis device according to claim 3, characterized in that it comprises a pin (27) provided with a threaded portion (30) in which is arranged at least one groove (32) adapted to receive an insert. Key-type (31), after screwing into the receiving bone material (15), which insert (31) positioned in said groove (32) then extends part of its structure out of the space requirement of the spindle ( 27) so as to sink and anchor in said bone material (15).   12.- osteosynthesis device according to any one of claims 1 or 2, characterized in that it comprises a screw (1) consisting of a head (3) extended axially by a central body (4) provided on its periphery of a thread (5), which screw head (3) incorporates at least one part (25) intended to be deformed, when said screw (1) is positioned in the bone receiving material (15), so as to sinking and anchoring in said bone material (15).