FR2745709A1

FR2745709A1 - Screw threaded retainer for bone fractures

Info

Publication number: FR2745709A1
Application number: FR9602977A
Authority: FR
Original assignee: CAFFINIERE JEAN YVES DE
Current assignee: CAFFINIERE JEAN YVES DE
Priority date: 1996-03-08
Filing date: 1996-03-08
Publication date: 1997-09-12
Anticipated expiration: 2016-03-08
Also published as: FR2745709B1

Abstract

The retainer has a screw (a) with a central unthreaded section (1). The screw also has a distal section (2) with a thread for spongy bone, and a proximal section (3) with a thread having a constant height. The screw can have a central channel to allow passage of a broach guide (4). Another proximal section (5) receives a turn screw which is channelled.

Description

VIS DE RAPPEL PAR COMPRESSION POUR OSTEDtiYHESE PECIGUT:
La présente invention concerne un type de vis utilisé en chirurgie osseuse pour toute fracture-séparation.COMPRESSION RECOVERY SCREW FOR OSTEDtiYHESE PECIGUT:
The present invention relates to a type of screw used in bone surgery for any fracture-separation.

Le mode de fixation de ces fractures est habituellement assuré par des vis introduites du côté opposé du trait de fracture. Ces vis sont caractérisées par un filetage distal tandis que leur corps en est dépourvu. Le vissage du fragment séparé permet son rappel vers la pièce osseuse principale grâce à l'appui de la tête de vis contre la corticale opposée. Ce procédé n'assure cependant pas le dosage de la compression et ne tient pas compte des variations de dureté du tissu osseux spongieux sur lequel la partie proximale du dispositif s'appuie.The method of fixing these fractures is usually ensured by screws introduced on the opposite side of the fracture line. These screws are characterized by a distal thread while their body is devoid of them. The screwing of the separated fragment allows its recall towards the main bone part thanks to the support of the screw head against the opposite cortex. This method does not however ensure the dosage of the compression and does not take into account the variations in hardness of the spongy bone tissue on which the proximal part of the device is based.

Le dispositif selon la présente invention permet de pallier à cet inconvénient auquel s'ajoute le fait que dans la plupart des cas il peut être placé en percutané sous simple contrôle radiologique avec l'amplificateur de brillance grâce à une instrumentation adéquate.The device according to the present invention overcomes this drawback to which is added the fact that in most cases it can be placed percutaneously under simple radiological control with the image intensifier thanks to adequate instrumentation.

Le disposif présente en première caractéristique une vis A (figure 1) composée de trois segments : un segment central cylindrique (1) dénué de filetage qui compose le corps intermédiaire de la vis. Un segment distal (2) disposant d'un filetage à hauteur croissante puis décroissante pour assurer l'ancrage de la vis dans le tissu osseux spongieux. Enfin, un troisième segment proximal (3), partie originale de la vis, dénué de tête mais site d'un filetage régulier de hauteur constante et de longueur variable.The device has as a first characteristic a screw A (FIG. 1) composed of three segments: a cylindrical central segment (1) devoid of thread which composes the intermediate body of the screw. A distal segment (2) having a thread with increasing then decreasing height to ensure the anchoring of the screw in the cancellous bone tissue. Finally, a third proximal segment (3), original part of the screw, devoid of head but site of a regular thread of constant height and variable length.

La vis A est canulée si nécessaire afin de permettre son guidage par une broche (4).
Elle dispose enfin à son extrémité proximale d'un embout (5) réservé à la prise du tournevis.The screw A is cannulated if necessary to allow its guidance by a pin (4).
Finally, it has at its proximal end a tip (5) reserved for taking the screwdriver.

Le dispositif présente en 2e caractéristique la pièce B (figure 2). C'est la pièce de vissage proximale qui vise à remplacer la tête d'une vis conventionnelle. La pièce B est un anneau et donc une pièce creuse qui dispose d'un canal central (6). Sa surface extérieure est munie d'un filetage large et de hauteur croissante de son extrémité proximale à son extrémité distale (7). Son extrémité distale dispose d'un embout (8) qui sert à recevoir un tournevis adéquat.The second feature of the device is part B (Figure 2). It is the proximal screwing part which aims to replace the head of a conventional screw. The part B is a ring and therefore a hollow part which has a central channel (6). Its outer surface is provided with a wide thread and of increasing height from its proximal end to its distal end (7). Its distal end has a tip (8) which is used to receive an adequate screwdriver.

La surface intérieure (figure3) (9) de la pièce B est munie d'un filetage à filet constant ce qui permet à la pièce B d'être vissée sur la partie filetée (5) de la vis A.The inner surface (figure 3) (9) of part B is provided with a constant thread which allows part B to be screwed onto the threaded part (5) of screw A.

Cette vis spéciale A est introduite (figure 4) dans la pièce osseuse grâce à un tournevis C dont la caractéristique est d'être canulé pour permettre le guidage par la broche (4). Surtout cet instrument dispose d'une poignée amovible (10) ce qui permet à l'instrument de servir de guide au tournevis de la pièce B, une fois la vis A en place, et la poignée (10) enlevée.This special screw A is introduced (FIG. 4) into the bone part using a screwdriver C, the characteristic of which is to be cannulated to allow guidance by the spindle (4). Above all this instrument has a removable handle (10) which allows the instrument to serve as a guide for the screwdriver of part B, once the screw A is in place, and the handle (10) removed.

La séquence suivante (figure 5) consiste en effet à glisser la pièce de vissage B sur le guide C grâce à un tournevis D disposant d'un canal central dont le diamètre lui permet d'être glissé sur la tige C.The following sequence (Figure 5) consists in sliding the screwing part B on the guide C using a screwdriver D having a central channel whose diameter allows it to be slid onto the rod C.

Ainsi l'opérateur peut il visser la pièce B sur le filetage (5) proximal de la pièce A (figure 6) et ainsi doser la compression dans le foyer de fracture. Thus the operator can screw the part B onto the thread (5) proximal to the part A (FIG. 6) and thus measure the compression in the fracture site.

Claims

1) Screwing device for fracture-separation characterized in that the screw A

has three sectors: a central body without thread (1), a distal sector (2) provided with a thread for cancellous bone and a proximal sector (3) provided with a thread with constant height threads.

2) Device according to claim (1) characterized in that the part A is provided with a central cannulation to admit a guide pin (4) and a proximal sector (5) intended to receive a cannulated screwdriver (C).

3) Device according to claims (1) and (2) characterized in that it further comprises a hollow part B consisting of a ring having an external thread (7) with increasing height threads and a thread interior (9) with constant threads allowing the screwing of this piece B on the thread (3) of the proximal end of the screw A.

4) Device according to claim (2) characterized in that the cannulated screwdriver C used to screw the part A is provided with a removable handle (10). O).

5) Device according to any one of the preceding claims, characterized in that the part B has a screwdriver D whose central part is hollow with a diameter allowing it to be adjusted on the screwdriver C after its removable handle 10 has been removed.