ORTHOPAEDIC MANIPULATOR FOR REDUCTION AND EXTERNAL FIXATION

Abstract: The application suggests a manipulator fit for being applied to the two stumps of a bony fracture to allow the same to be reduced and stabilized. To this end, it allows through micrometric displacements all the degrees of freedom for the two fragments and all the possible rotations, by means of two half-sectors (1, 2) sliding on each other. The extremities of the two half-sectors are provided with a seat (7, 8) for a bush (9, 10) which can be rotated and/or axially displaced for a corresponding displacement of the bone part.

Description: ORTHOPAEDIC MANIPULATOR FOR REDUCTION AND EXTERNAL FIXATION The method of external fixers for the therapy of skeletal fractures of limbs has been in use for many years in traumatologic medicine. Such a method often substitutes the use of immobilizing plastering apparatuses which always involve a long rehabilitation stage and at the same time often avoids an operation in the open air. However, it is often the difficulty in practising reduction maneuvers that allow an optimum anatomic reconstruction of the fractured skeletal segment that limits its utilization. The various commercially available external fixer systems do not allow such maneuvers, or they allow them only partly, often with the risk of making the already obtained result worse, and often with a complicated and approximative mechanics. The object of the present patent for industrial invention is to suggest a means that makes the reduction maneuvers easier allowing micrometric displacements of the bony fragments to be reduced. Moreover, it allows the maneuvers to be practised independently of each other, so as not to compromise the already obtained reduction result. The manipulator is realized to be removed or to remain applied to a limb through the proper fixers, and to this end it is endowed with clamping members that ensure a stable maintenance of the reached position. According to the suggested solution idea the realized manipulator allows, by acting upon proper screw handlebar grips, a micrometric displacement of the fractured bony fragments in all the possible directions realizing all the degrees of freedom and the relative axial and angular rotations. The manipulator is shown in an embodiment thereof given as a matter of example and not of limitation in the annexed plates of drawings. Plate I presents it in Figure 1 in an axonometric front side view that shows it in the stage of its utilization applied to a fixer of a known type. Plate II in Figure 2 puts into evidence in a top axonometric view the maneuver of angular rotation in the horizontal plane made possible by the manipulator; in Figure 3 it illustrates the particular mating between the toothed sector and the endless screw that allows some rotation maneuvers. Plate III in Figure 4 shows in a rear axonometric view the possible maneuver for the axial slide of the fragments. Plate IV in Figure 5 represents the manipulator in a rear axonometric view that puts into evidence the maneuver for the transverse slide in the horizontal plane. Plate V, finally, represents in Figure 6 a front view of the detail of the sector that allows the axial rotation of the fragments. With reference to the figures, the manipulator is made up of a sector that extends by a quarter of a circle and is comprised of two portions 1 and 2 endowed with guides fit for sliding angularly on each other when the screw 3 that is located in the slit 4 which goes through a large part of the sector 2 is loosened. In this way the sector can be reduced, assuming angles that range from about 60° to about 120°. The screw 5 that engages with the toothing 6 provided on a portion of the contact faces of the two sectors allows a micrometric displacement of a sector with respect to the other. Each sector at the not engaged extremity projects respectively into the blocks 7 and 8, so shaped as to receive the bushes 9 and 10 displaced by the screws 11 and 12 and endowed along a portion of their cylindrical surface with toothings 13 that engage respectively with endless screws 14 and 15 slightly angled with respect to the orthogonal axis of the screw itself, as put into evidence in Figure 3. From bushes 9 and 10 stems 16 and 17 project, which by means of proper transmissions end at the clamps of the fixers 18 and 19. On the stem 17 the slab 20 is provided of the fixer which connects it to the slide bar of the fixer 21 or other axial slide system. Such a maneuver, realized througl a slide bar of the known fixer, will be able to be realized with any other slide system that acts along the longitudinal axis of the bar of the manipulator. The blocks 7 and 8 are moderately elastic and endowed with transverse screws 22 and 23 fit to tighten them in order to clamp the motion of the internal bushes. From what has been illustrated it is apparent that by acting upon the described screws the following displacements of the bony fragments 24 and 25 connected to the relevant clamps of the fixer can be per ormed: a) by acting upon the screw 26 of the fixer or other known axial slide system one determines the approaching or the removal of the fragments along the longitudinal axis; b) by acting upon the screw 12 one determines the transverse translation in the vertical plane of the fragment 24 with respect to the fragment 25; c) by acting upon the screw 11 one determines the transverse translation in the horizontal plane of the fragment 25 with respect to the fragment 24; d) by acting upon the screws 14 and 15 one causes the relative angle of the fragments in the vertical and horizontal plane; e) by acting upon the screw 5, finally, one determines the angular displacement of the two half-sectors 1 and 2 and thus the rotation of the fragments about their own axis. The geometric characteristics that are to be respected in the realization of the fixer are: the coplanarity of the axes of the screws 11 and 12 and their convergence into the fracture focus. When the fracture has been reduced, the screws 3 and the screws 22 and 23 are tightened, so as to clamp the manipulator in the last reached position, it in this position can remain applied to the limb for possible subsequent adjusting maneuvers; this is made possible by its reduced size and by its extremely restricted weight. It is however possible to remove it also by clamping the fixers with a simple connector of a known type. The light weight and smallest encumbrance characteristics are a consequence of the solutions adopted for the realization of ail the movements that occur according to the suggested solution idea with an extremely compact instrument. Formal and structural variations can be made to the solution idea, without departing from the scope of the invention, which is defined by the following claims.

Claims: CLAIMS : 1. A manipulator for reduction maneuvers applicable to external fixers in use in traumato- logic and orthopaedic medicine, characterized in that it allows the displacement of the fractured bony fragments giving them three degrees of freedom and any possible rotation. 2. A manipulator according to the preceding claim and to the same end thereof; characterized in that the displacements occur continuously and micrometrically. 3. A manipulator according to the preceding claims and to the same end thereof, characterized in that it is made up of a circular sector that allows an angular range of about 60° and is assembled in two half-sectors fit for sliding on each other to reduce the aperture angle. 4. A manipulator according to the preceding claims and to the same end thereof, characterized in that at the extremity of the two half-sectors a seat is provided for containing a bush with a portion of the lateral surface longitudinally toothed to mate with and endless screw, said bush being also endowed with a screw for making it to axially displace in its seat. 5 ' A manipulator according to the preceding claims and to the same end thereof, characterized in that the axes of the bushes lie in a same plane and converge to the focus of the fracture. 6. A manipulator according to the preceding claims and to the same end thereof, characterized in that the axial motion of the bushes though proper screws ensures the translations in the horizontal and vertical plane of the bony fragments connected to the manipulator through clamps of the fixer connected to the bushes themselves. 7- A manipulator according to the preceding claims and to the same end thereof, characterized in that by acting upon the endless chains with the axis slightly angled with respect to that of the bushes that mate therewith the angulation of the fragments in the horizontal and in the vertical plane is ensured. 8. A manipulator according to the preceding claims and to the same end thereof, characterized in that the slide of the half-sectors by means of proper micrometric screws allows the rotation of the bony fragments about their own axis. 9. A manipulator according to the preceding claims and to the same end thereof, characterized in that proper screws clamp both the seats and the circular sector once the desired position of the bony fragments has been reached.

Inventors: CAMPOPIANO ASCANIO, CAMPOPIANO, ASCANIO
Applicants: CAMPOPIANO ASCANIO, CAMPOPIANO, ASCANIO
Application year: 1991
Main classification: A61B17
IPC codes: A61B17