FR2668919A1 - Intramedullary pin and its gripping tool - Google Patents

Abstract

A distal end of the pin comprises an abutment (3) which is preferably spheroidal and has a transverse section in which is inscribed the substantially circular section of the body (2), and an intermediate prismatic portion (4) which is situated between the abutment (3) and the body (2) and which has a polygonal section, preferably an isosceles triangle, inscribed within the section of the body (2). The proximal end of the pin is preferably in the shape of a spatula oriented precisely with reference to a ridge of the prismatic portion. The gripping tool (5) comprises two separable jaws (62, 72) which are substantially continuous along two opposite contact surfaces (63, 73). First recesses (64, 74) in the jaws have, together, a transverse section (DM) greater than the maximum longitudinal section (D) of the abutment (3) in order to receive the portion, and second recesses (65) have, together, a transverse section susbtantially complementary to that of the intermediate portion (4) of the pin in order to receive the said portion.

Description

Intra-medullary spindle and its gripping tool
The present invention relates to an intramedullary spindle having a slender body with a substantially circular section, as well as the gripping tool for maneuvering the spindle, particularly with a view to stable elastic centro-medullary plugging.

 Born from a subtle dosage of restraint and reduction means, stable elastic central # nedullary plugging is based on the principle of an elastic intra-medullary support placed in a closed hearth. This tutor is represented by an elastic, crutched and curved pin, allowing at least three support points. This biomechanical concept creates a coherent system which can adapt to all diaphyseal and metaphyseal fractures in children in particular.

 This technique, avoiding prolonged bed rest, although very satisfactory for maintaining a fracture plan, poses, in 10 to 15% of these clinical cases, problems of subcutaneous infection by external migration of the pins. In fact, the distal end of the spindle having to be cut to length as a precautionary measure, this operation can be carried out simply by means of cutting pliers. This results in a very aggressive part of the coat, this same part being able to damage the subcutaneous tissues in the event of migration of this pin towards the outside.

 In addition, in the case of pins having flattened distal ends in the form of spatulas or pallets, also called "nails ENTER", the effort to be exerted to drive these pins in rotation is such that the corresponding gripping tool is slid on the spindle for lack of grip, or damage the spindle by too much aggressiveness.

 Finally, it should be noted that when the bone consolidation is sufficient, the extraction of these pins is not very easy because the fixing of an extraction tool requires such efforts that, often, the shearing of the pin occurs before even that it is entirely explanted.

 the various known pins currently used, for example provided with a buttoned distal end, with a threaded distal end provided with a protective cap, or else with a distal end curved after section, provide only partial solutions and do not not give satisfaction to the practitioner.

 the present invention aims to provide an intra-medullary spindle end which, without using a shell, remedies a migration of the spindle, without the latter being aggressive, while offering facilities for gripping the spindle, that either in traction and thrust, or in rotation thereof.

 To this end, an intramedullary spindle is characterized by a distal end comprising a stop having a cross section in which the body section is inscribed, and a prismatic section intermediate between the stop and the body and having a polygonal section inscribed in body section.

 the stopper is preferably spheroidal or polyhedral with chamfered or rounded edges to avoid any operational injury.

This stop prevents spindle migration. When the abutment is trapped in a gripping tool according to the invention, the abutment can be used as a longitudinal support to extract or introduce the spindle.

 The prismatic section preferably has a regular cross section, for example isosceles triangular, with edges also chamfered or rounded. This section is intended to be tightened without excess by the gripping tool to touch the spindle and orient it in the medullary canal. The section is not aggressive since it does not project transversely from the body of the spindle.

 In addition, the pins according to the invention are supplied with dimensions and therefore do not require a reduction in length preoperatively. the standard dimensions of the pins are preferably in accordance with the ANDERSON table.

 The proximal end of the pin can be shaped like a thin spatula to help consolidate the fracture.

Preferably, the curvature of the spatula is oriented relative to one of the reference edges or faces of the prismatic section in order to properly position the spindle.

 The gripping tool according to the invention is characterized by two separable jaw elements, substantially contiguous along two facing contact surfaces, and comprising first recesses having together a cross section greater than the largest longitudinal section of the spindle stop to receive said stop, and second recesses having a cross section substantially similar to that of the intermediate spindle section to receive said spindle section.

 the first recesses, such as grooves which have a cross section substantially similar to the longitudinal section of the spindle stop and which are substantially perpendicular to the longitudinal axis of the tool and the spindle, may be wider than the section longitudinal of the stopper, so as to accommodate spindle stops of various sizes. In this case, the clamping force is almost zero.

 the length of the second recesses, such as longitudinal grooves, can be substantially equal to that of the prismatic section of the spindle, so that the jaws of the gripping tool trapping the section, without substantially tightening, are wedged both in rotation and in translation relative to the spindle, and therefore become one with the spindle.

 A mark reproducing the proximal end of a spatula-shaped pin is engraved on the outside of the tool to indicate the orientation of said proximal end relative to the second recesses.

 Preferably the tool comprises a hollow cylindrical body in which are partially housed and with longitudinal sliding of the distal ends of the jaw elements, elastic return mayens for radially spreading the jaw elements in the hollow body, a slide having a proximal end longitudinally integral with the distal ends of the jaw elements and sliding longitudinally in the hollow body, and a nut screwed to a distal end of the slide to translate the slide in order to bring the jaw elements closer and further apart from one another.

Other characteristics and advantages of the present invention will appear more clearly on reading the following description of several preferred embodiments of the invention with reference to the corresponding appended drawings in which
- Fig. 1 is a longitudinal view from the side of an intL <-medullary bruche according to the invention;
- Fig. 2 is a cross-sectional view in the distal end of the pin taken along the line II-II in FIG. 1;
- Fig. 3 is a front view of the spatulated proximal end of the spindle;
- Fig. 4 is an exploded perspective view of a distal end of the spindle according to the invention and of the jaw elements of a gripping tool presented for gripping the spindle;
- Fig. 5 is a view in axial longitudinal section of the distal spindle end according to FIG. 4 trapped in the jaws of the tool;
- Figs. 6 and 7 are cross-sectional views taken along lines VI-VI and VII-VII of FIG. 5, respectively;
- Fig. 8 is a section similar to FIG. 6 and relating to a polyhedral stop housed in a polyhedral cavity of tool jaws which have contact surfaces substantially coinciding with the longitudinal axis of the spindle;
- Fig. 9 is a section similar to FIG. 7 and relating to jaws having contact surfaces substantially coinciding with the longitudinal axis of the spindle;
- Fig. 10 is a section similar to FIG. 7 and relating to separated jaws intended to receive several similar sizes of distal spindle end;
- Fig. 11 is a longitudinal view partially in axial section, of a gripping tool for precise movement of the jaw elements relative to one another;
- Fig. 12 is a longitudinal front view of contact of a jaw element with a longitudinal groove proximal to the tool of the
Fig. he ;;
- Fig. 13 is a view in axial longitudinal section taken along the line XIII-XIII of FIG. 12
- Fig. 14 is a longitudinal front view of contact of a flat jaw element proximal to the tool of FIG. he;
- Fig. 15 is a view in axial longitudinal section taken along the line XV-XV of FIG. 14, and
- Fig. 16 is a longitudinal view of the proximal end of the tool of FIG. 11.

 With reference to FIG. 1, an intramedullary pin 1 comprises a slender, substantially cylindrical body 2 having a distal end 3-4 and a proximal end 5.

 The body 2 may be smooth, provided with helical or longitudinal grooves, grooves, or else slots, and may have a straight or curved longitudinal profile, or else be made up of straight and / or curved sections joined by elbows. The body 2 can be monolithic, as illustrated, or be formed by butted body sections.

 The distal end 3-4 of the spindle 1 comprises a stop 3 and an intermediate section 4 extending substantially longitudinally between the stop 3 and the body 2. The stop and the intermediate section are made of the same material as the spindle body , such as steel, metal alloy, titanium or teflon for example, and are preferably obtained by forging and machining.

 The stop 3 illustrated in Figs. 1 and 4 is spheroidal and is centered on the longitudinal axis XX of the spindle body 2. The diameter D of the spherical stopper 3 is greater than the diameter d of the upper spindle body 2. Typically, the difference in diameters Dd is between 1 and about 2 Tata.

 The interi # area 4 illustrated in Figs. 1 and 2 has a triangular cross section which is inscribed in the circular cross section of diameter d of the spindle body 2. The longitudinal axis of the intermediate section is coincident with that XX of the neighboring end of the body 2. Preferably, the cross section of the section 4 is isosceles or equilateral, in order to provide two symmetrical faces 41 facilitating the machining of an additional groove 65 in one 62 of the jaws of the gripping tool, and a bearing face 75 for the other jaw 72 of the tool, as will be seen below. The edges 43 of the section 4, here three in number, are chamfered or rounded to avoid any risk of injury. In practice, the length L of the section 4 is equal to approximately 10 na.

According to other variants of the spindle end,
- the stop can be convex and ellipsoisdale, oval or barrel-shaped, or more generally a solid of revolution, or else can be cubic, octohedral or more genetically polyhedral 3a (Fig. 8), preferably regular, in which s' enter the cross section of diameter d of the spindle body 2; in the latter case, the edges 31a of the stop are chamfered or rounded; and
- The cross section of the intermediate section can be square, hexagonal, octagonal or more generally polygonal, preferably regular. The intermediate section thus prismatic or substantially pyramidal can be straight, that is to say having a longitudinal axis parallel or collinear with the longitudinal axis XX of the spindle body, or be oblique or substantially curved, that is to say having a longitudinal axis intersecting or tangent to the longitudinal axis of the spindle body, to facilitate gripping of the spindle during certain implantations.

 The proximal end 5 of the pin 1 is in the form of a thin spatula, as shown in Figs. 1 and 3.

The spatula 5 is symmetrical with respect to a longitudinal mediator plane of the intermediate section 4 having trace YY in the
Figs. 2 and 3 and which passes through the top edge 43S of section of section 4 adjacent to two faces of section 4. The thickness E of the spatula between two parallel faces If symmetrical with respect to the plane YY is smaller than the diameter d of the spindle body 2 and typically is substantially less than a third of the diameter d.

 The edges 52 of the spatula 5 are curved and substantially parallel. The curvature of the tip and more particularly that of the edges 52 are oriented in the direction of said edge vertex 435 of the intermediate section from the spindle body 2. In the plane of symmetry YY, the center of curvature CE of the edges 52 is same side as said vertex 435 with respect to the longitudinal axis of spindle XX.

This orientation of the spatula 5 relative to the intermediate section 4 makes it possible to monitor the position of the spatula, for example using an X-ray device, introduced into the fractured region, and to rotate the spindle accordingly so that the spatula brings together the fragments of the traumatized bone. Typically the transverse height H of the proximal spatula 5 is between 6 and 9 mm.

The standard dimensions of pins according to the invention can be as follows, where LB denotes the overall length of a pin
- d = 2 mm; D = 3.5 mm; E = 0.7 mm; H = 6 mm;
and length LB = 130, 150, 170 or 190 mm;
- d = 2.5 mm; D = 3.5 mm; E = 0.8 mm; H = 6.75 mm;
and length LB = 150, 170, 190, 210 or 230 mm;
- d = 3 mm; D = 4.5 mm; E = 1 mm; H = 7.3 mm;
and length LB = 210, 230, 250, 270 or 290 mm;
- d = 3.5 mm; D = 4.5 mm; E = 1 mm; H = 7.95 mm;
and length LB = 270, 290, 310, 330 or 350 mm;
- d = 4 mm; D = 5 mm; E = 1.2 mm; H = 8.7 dwarf;
and length LB 330, 350, 370, 390, 410, 430 or 450 mm.

 With reference to Figs. 4 and 5, a gripping tool for implantation or explantation of the spindle 1 in particular with respect to a medullary canal comprises two monoblock jaw elements 6 and 7 which are separable on either side of a longitudinal plane of contact. Elements 6 and 7 are metallic, for example stainless steel. Each of these elements 6, 7 comprises a substantially semi-cylindrical section 61, 71 and a substantially semi-biconical jaw 62, 72. When the plane longitudinal surfaces of opposite contact 63 and 73 of the elements 6 and 7 have substantially identical contours and are applied one on the other, the sections 61 and 71 form a cylindrical handle here, preferably knurled, and the jaws 62 and 72 form a biconical sheath intended to grip the distal end of pin 3-4.

 The assembly of the two elements 6 and 7 can be kept by manual tightening around the handle 61-71, or by quick attachment means (not shown), such as one or more plastic collars with notches, or pins or flexible tabs on one of the contact surfaces 63 and 73 snapping into respective holes or grooves on the other contact surface. A connecting hinge (not shown) can be provided between the elements 6 and 7, for example at the ends of the handle sections 61 and 71, or else the elements 6 and 7 are pivotally mounted around a transverse articulation axis and form the arms of a clamp. As a practical embodiment, a gripping tool allowing precise movement of the jaws relative to one another will be described later with reference to FIG. 11.

 According to lot the realization illustrated in Figs. 4 and 5, the jaws 62 and 72 ccmprendent of the first recesses in the form of transverse grooves 64 and 74, and of the second recesses in the form of axial longitudinal grooves 65 and 75. According to the illustrated embodiment, the grooves 64, 74 are substantially orthogonal to the grooves 65, 75.

 The first grooves 64 and 74 together have a substantially circular cross section in which the longitudinal diametral section of the stop 3 of the spindle 1 is contained, that is to say have a diameter DMs # greater than D, when the surfaces of contact 63 and 73 are substantially applied to each other.

According to the illustrated embodiment, the contact surfaces 63 and 73 substantially coincide with the bearing face 42 of the triangular section 4 of the spindle which is opposite to the locating top 43S, when the jaws 62 and 72 trap the end of the spindle 3 -4. In this embodiment shown in Figs. 5 and 6, the cross section of the groove 64 has a semi-circular bottom 641 having the diameter DM and parallel walls 642 tangential to the bottom 641 and perpendicular to the surface 63, and the cross section of the groove 74 is a circular arc of diameter DM having a length less than half a circumference.

 The diameter DM is chosen to be substantially greater than the largest diameter of the stops 3 of the various spindle sizes according to the invention. Typically, for the aforementioned standard dimensions, DM is equal to 5.5 mm.

 According to other variants, the grooves 64 and 74 may together have a cross section strictly complementary to the largest longitudinal axial section of the stop 3, and when the contacting surfaces 63 and 73 are provided to coincide substantially with the longitudinal axis XX of the spindle, the grooves 64 and 74 are semi-circular.

More generally, in place of the grooves 64 and 74, two cavities 64a and 74a can be provided respectively formed in the tool jaws 62a and 72a and having together a shape substantially coEplementary or similar to the shape of the stop, as morrtré à la Fig. 8. morrtréWhen the transverse section of the first recesses, grooves or cavities, is strictly complementary to the largest longitudinal section of the stop taken along the longitudinal axis
XX of the stop, the first recesses block the longitudinal translation of the tool relative to the stop 3, 3a, which facilitates the tensile thrust of the spindle 1.

 In Figs. 4 to 7, the zendes grooves 65 and 75 together have a triangular cross section which is substantially complementary to the triangular cross section of the intermediate section 4 of the spindle 1, when the contact surfaces 63 and 73 are substantially contiguous. Knowing that according to the embodiment illustrated in Figs. 5 and 7 the surfaces 63 and 73 substantially coincide with the bearing face 42 of the section 4 when the jaws 62 and 72 enclose the end of spindle 3-4, the groove 65 in the first jaw 62 has a V-shaped section with walls parallel to the symmetrical faces 41 of the section 4, and the groove 75 in the second jaw 72 is leveled into a flat.

 According to another variant shown in FIG. 9, the contact surfaces 63b and 73b of the jaws 62b and 72b substantially coincide with the longitudinal axis XX of the end of the spindle 3-4. In this case, the longitudinal groove 65b of the first jaw 62b has a depth less than the height of the section 4, and the longitudinal groove 75b of the second jaw 72b has a rectangular cross section having a width substantially greater than the width of the face of support 42 of section 4.

 According to another variant shown in FIG. 10, the depth of the longitudinal groove 65c in the first jaw 62c is less than the height Hr of the cross section of the intermediate spindle section 4 taken between the top of the locating edge 43S and the opposite spindle bearing face 42 at said summit, as according to FIG. 9; the second jaw 72c has a flat face 75c to be applied to the spindle bearing face 42. When gripping the intermediate section 4, the contact surfaces 63c and 73c-75c of the jaws are spaced apart in parallel from a clearance JE which depends on the height HT of the section 4, and which is less than this. Preferably, the depth of the groove 65c, of the order of Hl'JE, is less than the smallest height of the sections 4 of the various spindle sizes, for example between the height of the smallest section of sections 4 and half of it for sections having substantially the same angle at the top in 43S. Under these conditions, the same pair of jaws 62c and 72c is used to grip an embroidery, regardless of the size of its proximal end 3-4.

 When the intermediate section 4 of the spindle 1 is contained in the second recesses, such as the grooves 65 and 75, at 65b and 75b, or 65c and 75c, the second recesses block the tool in axial rotation relative to the section 4 ce which allows the spindle 1 to be rotated on itself # and to orient it properly in the medullary canal. A mark RE reproducing the proximal end 5 of the spindle 1 is engraved longitudinally on one of the jaw elements, such as the first jaw element 6, as shown in FIG. 5. The reference RE has a curvature oriented towards the groove 65 so as to indicate to the surgeon the orientation of the proximal end 5 with respect to the grooves 65 and 75 and therefore with respect to the edge and the reference face 43S and 42 of the intermediate spindle section.

 Preferably, the length of the second grooves 65 and 75 is substantially equal to the length L of the intermediate section 4 of the spindle 1. The ends 66 and 76 of the jaws 62 and 72 abut against the shoulder 21 forming the transition between the section 4 and the body 2 of the spindle 1, and the walls of the grooves 64 and 74 contiguous to the mouth of the grooves 65 and 75 abut against the stop 5. Under these conditions, the anterior portions of the jaws 62 and 72 containing the grooves 65 and 75 are blocked in longitudinal translation between the stop 3 and the body 2, which allows the tool 5 to introduce the pin 1 into the medullary canal by pushing it, or to extract the pin 1 from the medullary canal by pulling it .Of course this translation can be combined with a rotation of the spindle 1, as described above.

 With reference to FIG. 11 is described below a gripping tool allowing a precise relative movement of the jaw elements 6c and 7c relative to each other. Elements 6c and 7c are shown in detail in Figs. 12, 13 and 14, 15 and have jaws 62c and 72c of the type illustrated in FIG. 10.

 The tool is in the form of a hollow cylindrical body 8 having a partly knurled external surface at least one month. A full cylindrical slide 9 shorter than the body 8 is mounted with axial longitudinal sliding in the body 8.

 A substantially sectional proximal end 91 of the slider 9 emerges in a wider proximal bore 81 of the tool body 8 which forms a sheath in which the distal semi-cylindrical sections 61c and 71c of the jaw elements 6C and 7c are inserted to slide. The proximal end 91 of the slider is fixed in two axial semi-cylindrical blind grooves 67c and 77c arranged opposite in the distal ends of the contact surfaces 63c and 73c of the elements 6C and 7c. A diametral pin 92 slidably crosses the sections d 'jaw element 61c and 71c and the frustoconical end 91 to secure them together both in longitudinal translation and in axial rotation; however, the sections 61c and 71c and the end 91 are translatable radially along the pin 92. A helical spring 82 is embedded in the bore 81 around the end of the slide 91, between the bottom of the bore 81 and the jaw element sections 61c and 71c.

 A radial cylindrical lug 93 is housed in a radial hole 78c of the distal section 61c of one 6C of the jaw elements, and completely crosses the hole 78c. The lug 93 has a first end which is intended to slide in a longitudinal groove 83 formed in the bore of the tool body 81, and a second convex end which is intended to abut against the end of the slide 91 in the grooves jaw element distals 67c and 77c.

 The jaw elements 6C and 7c are kept apart and are applied in pern m against the bore 81 by means of a doubly bent lamella spring 94 which is housed longitudinally against the facing surfaces 63c and 73c of the jaw elements. A distal end of the strip 94 is fixed to the contact surface 73c of one of the jaw element sections 71c by means of a small radial screw 941 which is screwed into a tapped hole 79c in the section 71c.

A proximal end of the strip 94 is applied by its own bending against the contact surface 63c of the other section of jaw element 61c. A longitudinal relief groove 791c substantially cat #> elementary of the lamella 94 is provided in the surface 73c, and a radial relief blind hole 69c is provided in the surface 63c and facing the threaded hole 79c, to allow application of the surfaces of contact of jaw elements 63c and 73c against each other.

 At the threaded distal end of the slider 9 is mounted a knurled nut 95 partially penetrating into the body 8 and applied against the distal face of the body 8 by the medial inside of an antifriction washer 96.

 As shown in Fig. 16, a curved mark PEc, similar to the mark RE, reproducing the proximal end 5 of the brcoe 1 is etched for example by laser on the tool body 8 and has a curvature oriented towards the V-shaped groove 65c of the element jaw 6c suitable for receiving the locating edge 43S of the intermediate spindle section.

 The use of the gripping tool is as follows.

 The nut 95 is unscrewed to separate the jaws 62c and 72c sufficiently to introduce between their grooves 64c and 74c and 65c and 75c the distal end 3-4 of a pin 1. Unscrewing the nut leads to a translation of the slide 9 towards the bore 81 under the action of the helical spring 82, and thanks to the guide of the lug 93 in the longitudinal groove 83 inside the tool body 8. The biconical jaws 62c and 72c gradually come out of the 'conical proximal orifice of the body 8 against which they abut, and consequently deviate gradually, parallel to the plane XX under the action of the elastic strip 94. The distal end 61c slides radially along the pin 92; similarly, the distal end 71c slides radially along the pin 92, but also along the lug 93.

 After positioning of the distal end of spindle 3-4 between the separated jaws 62c and 72c, the nut 95 is screwed onto the slide 9 which is then translated in the opposite direction, in the direction of the nut and by compressing the spring 82 The biconical jaws progressively penetrate into the bore 81, sliding along its conical orifice against the restoring force of the strip 94, and approach each other. The screwing of the nut 95 is stopped when the grooves 65c and 75c enclose the prismatic intermediate section 4 of the spindle substantially without play or with little play.

Claims (19)

 1. intramedullary spindle (1) comprising a slender body (2) with a substantially circular section, characterized by a distal end comprising a stop (3) having a cross section in which the section of the body (2) is inscribed, and a prismatic section (4) intermediate between the stop (3) and the body (2) and having a polygonal section inscribed in the section of the body (2).  2. Spindle according to claim 1, characterized by a convex stop of revolution, preferably spherical (3).  3. Spindle according to claim 1, characterized by a polyhedral stop (3a), preferably with chamfered or rounded edges (31a).  4. Spindle according to any one of claims 1 to 3, characterized by a regular cross section of the Intermediate section (4), preferably with chamfered or rounded edges (43).  5. Spindle according to any one of claims 1 to 3, characterized by a triangular cross section of the intermediate section (4), preferably isosceles and with chamfered or rounded edges (43).  6. Brooch according to any one of claims 1 to 5, characterized by a proximal end in the form of a thin spatula (5).  7. Spindle according to claim 6, characterized in that the curvature of the spatula (5) is oriented towards one of the edges (43S) or faces (42) of the prismatic intermediate section (4).  8. Spindle according to claim 6 or 7, characterized in that the spatula (5) is symmetrical with respect to a longitudinal mediating plane (YY) of the intermediate prismatic section (4).  9. gripping tool for the spindle according to any one of claims 1 to 8, characterized by two separable jaw elements (6, 7), substantially contiguous along two facing contact surfaces (63, 73), and comprising first recesses (64, 74) having together a cross section (DM) greater than the largest longitudinal section (D) of the spindle stop (3) for receiving said stop, and second recesses (65, 75) having together a cross section substantially similar to that of the intermediate spindle section (4) for receiving said spindle section.  10. Tool according to claim 9, characterized in that the first recesses are grooves (64, 74) extending transversely to the distal end of the spindle (3-4), and have a cross section substantially similar to the longitudinal section of the stop (3).  11. Tool according to claim 9 or 9o10, characterized in that the first recesses are cavities (64a, 74a) together having a shape substantially similar to that of the stop (3a).  12. Tool according to any one of claims 9 to 11, characterized in that the second recesses are second grooves (65, 75) extending longitudinally at the distal end of the spindle (3-4).  13. Tool according to claims 10 and 12, characterized in that the first grooves (64, 74) are substantially orthogonal to the second grooves (65, 75).  14. tool according to any one of claims 9 or 13, characterized by a depth (HT-JE) of one of the second recesses (65c) less than the height (HT) of the transverse section of the spindle inter-sectional section (4) taken between a face (42) of said section and a top (43S) of said section opposite to said face (42).  15. Tool according to any one of claims 9 to 14, characterized in that the facing contact surfaces (63, 73) are adapted to substantially coincide with a face (42) of the intermediate section (4) against which s 'supports one (75) of the second recesses equivalent to a flat, the other second recess (65) having a V-shaped cross section.  16. tool according to any one of claims 9 to 15, characterized in that the facing contact surfaces (63, 73) can be positioned on either side of the longitudinal axis (YX) of the end spindle distal (3-4) when taking a spindle (1).  17. Tool according to any one of claims 9 to 16, characterized in that the length of the second recesses (65, 75) is substantially equal to that (L) of the intermediate spindle section (4).  18. Tool according to any one of claims 9 to 17, characterized by a mark (RE; PEc) reproduced from a proximal spindle end (5) in the shape of a spatula and engraved on the outside (62; 9) of the tool for indicating the orientation of said proximal spindle end relative to the second recesses (65, 75).  19. Tool according to any one of claims 9 to 18, characterized in that it comprises a hollow cylindrical body (8) in which are partially housed and with longitudinal sliding of the distal ends (61c, 71c) of the jaw elements (6c, 7c), elastic return means (94) for radially spreading the jaw elements (6c, 7c) in the hollow body, a slide (9) having a proximal end (91) integral longltudnalement of the distal ends (61c , 71c) jaw elements and sliding longitudinally in the hollow body (8), and a nut (95) screwed to a distal end of the slide (9) to translate the slide in order to bring the jaw elements (6c, 7c) in relation to each other.