Title of Invention  "INTRAMEDULLARY NAIL" 

Abstract  The intramedullary nail (1) has A) a distal end (2) suitable for insertion in the medullary space, wherein the segment of the intramedullary nail (1) facing the distal end (2) has a diameter D, B) a proximal end (3), C) a central longitudinal axis (4); and D) several cross holes (5) with a hole axis (6), each of which defines a virtual drill cylinder (8) with a cylinder axis (9) corresponding to the hole axis (6) of the defining cross hole (5), wherein E) the drill cylinders (8) of at least two cross holes (5) penetrate each other. The cylinder axes (9) of the two mutually penetrating drill cylinders (8) do not have any common intersection point P on the longitudinal axis (4). This results in improved mechanical strength compared to the state of the art, without any need for the size of the cross section of the intramedullary nail to be increased 
Full Text  The invention relates to an intramedullary nail in accordance with the generic term of Patent Claim 1, specifically for the distal tibia. The state of the art already includes intramedullary nails that have two intersecting cross holes at the same height, so that the same intramedullary nail can be used both for a right and for a left tubular bone. The disadvantages of this prior known arrangement is that the two (or even more) holes intersect and their axis of intersection lies on the longitudinal axis of the nail, with the result that a relatively large quantity of material is taken from the cross section of the intramedullary nail, which in turn leads to considerable mechanical weakening of the intramedullary nail at this point. The invention is intended to remedy this situation. The invention is based on the problem of creating an intramedullary nail with two (or more) intersecting cross holes that has improved mechanical strength compared to the state of the art described above, but which does not require the size of the cross section of the intramedullary nail to be increased. The invention solves the specified task by providing an intramedullary nail having the features of Claim 1. One variation of this invention is that the cylinder axes of the two mutually penetrating drill cylinders meet at an intersection point P which is at a distance d > 0 from the longitudinal axis. The distance d relative to the diameter D of the intramedullary nail is advantageously in the range 0.0001 D One further variation is that the cylinder axes of the two mutually penetrating drill cylinders are slanted and have as shortest distance the length x > 0. The length x in this system should be less than half the total of the two diameters of the mutually penetrating drill cylinders to enable the two drill cylinders to be penetrated. The section S of the length x representing the shortest distance between the two slanted cylinder axes can run parallel or at an angle to the longitudinal axis and have a shortest distance y > 0. The distance y is advantageously less than D/2, but greater than 0.4 D. In a further embodiment, the cylinder axes of the two mutually penetrating drill cylinders lie in a level orthogonal to the longitudinal axis. In another embodiment, the cylinder axes of the two mutually penetrating drill cylinders are in contrast in one level that is penetrated by the longitudinal axis at an angle a, wherein 0° In a further embodiment, the cylinder axes of the two mutually penetrating drill cylinders intersect at an angle ß, wherein 30° In a preferred embodiment, the mutually penetrating drill cylinders are provided with two separate entrance points into the intramedullary nail, but only one common exit from the intramedullary nail. The advantage of this system compared to one with 4 openings is that this system has less material loss, i.e. greater strength of the intramedullary nail. The diameter DB of the mutually penetrating drill cylinders advantageously measures at most 0.6 times, but preferably at most 0.5 times of D. In a further embodiment, the intramedullary nail is provided with a longitudinal hole coaxial to the central longitudinal axis. The bigger the diameter is of this hollow relative to the diameters of the drill cylinders, the greater can be the angle between the mutually penetrating cross holes, without any impairment to the cross section area of the intramedullary nail, i.e. without any lessening of the strength of the intramedullary nail. The invention and refinements of the invention are described in more detail in the following on the basis of partially schematic illustrations of several embodiments. Fig. 1 shows a front and rear view of the intramedullary nail with two intersecting cross holes; Fig. 2 shows a front view of the intramedullary nail with a schematic, perspective view of the drill cylinders; Fig. 3 shows an orthogonal cross section through the intramedullary nail according to Fig. 2 in the range of the intersecting cross holes; and Fig. 4 shows a schematic perspective view of two mutually penetrating drill cylinders with slanted cylinder axes. The intramedullary nail illustrated in figures 1 to 3 is provided with a distal end 2 suitable for insertion in the medullary space of a tubular bone, a proximal end 3, a central longitudinal axis 4 and two cross holes 5 with a hole axis 6, each of which defines a virtual drill cylinder 8 with a cylinder axis 9 corresponding to the hole axis 6 of the defining cross hole 5. The intramedullary nail has generally a constant diameter D and a longitudinal hole 10 coaxial to the central longitudinal axis 4. As illustrated in Fig. 3, the drill cylinders 8 of the two cross holes 5 penetrate each other, wherein the cylinder axes 9 of the two mutually penetrating drill cylinders 8 intersect at point P, which is at a distance d = 0.4 D from the longitudinal axis 4. In other words, the point P does not lie on the longitudinal axis 4 of the intramedullary nail. The mutually penetrating drill cylinders 8 are provided with two separate entrance points in the intramedullary nail 1, but only one common exit from the intramedullary nail 1. The cylinder axes 9 of the two mutually penetrating drill cylinders 8 are placed in a level orthogonal to the longitudinal axis 4, corresponding to the plane of projection of Fig. 3. The cylinder axes 9 of the two mutually penetrating drill cylinders 8 can, however, also be in one level, which is penetrated by the longitudinal axis 4 at a defined angle a (Fig. 2). In the illustrated example, the cylinder axes 9 of the two mutually penetrating drill cylinders 8 intersect at an angle ß of 60°. The diameter DB of the mutually penetrating drill cylinders 8 measures in the illustrated example 0.3 times D. As illustrated in Fig. 4, the cylinder axes 9 of the two mutually penetrating drill cylinders 8 in an alternative embodiment can also run in slanted direction and have a shortest distance 11 of the defined length x, which is smaller than half the total of the two diameters of the mutually penetrating drill cylinders 8. The section S of the length x representing the shortest distance 11 between the two slanted cylinder axes 9 runs in the illustrated example parallel to the longitudinal axis 4 and has a shortest distance y > 0. The section S can, however, also run slanted in relation to the longitudinal axis 4. The distance y is in the range of D/2 > y > 0.4 D. We claim 1. Intramedullary nail (1) with A) a distal end (2) suitable for insertion into the medullary space, wherein the segment of the intramedullary nail (1) facing the distal end (2) has a diameter D; B) a proximal end (3); C) a central longitudinal axis (4); and D) several cross holes (5) with a hole axis (6), each of which defines a virtual drill cylinder (8) with a cylinder axis (9) corresponding to the hole axis (6) of the defining cross hole (5), wherein E) the drill cylinders (8) of at least two cross holes (5) penetrate each other, F) the cylinder axes (9) of the two mutually penetrating drill cylinders (8) have no common intersection point P on the longitudinal axis (4) characterised in that G) the cylinder axes (9) of the two mutually penetrating drill cylinders (8) lie in a plane orthogonal to the longitudinal axis (4). 2. Intramedullary nail (1) as claimed in claim 1, wherein the cylinder axes (9) of the two mutually penetrating drill cylinders (8) intersect at an intersection point P, which is at a distance d > 0 from the longitudinal axis (4). 3. Intramedullary nail (1) as claimed in claim 1, wherein the cylinder axes (9) of the two mutually penetrating drill cylinders (8) are slanted and have a shortest distance (11) of length x > 0. 4. Intramedullary nail (1) as claimed in claim 3, wherein the length x is less than half the total of the two diameters of the mutually penetrating drill cylinders (8). 5. Intramedullary nail (1) as claimed in claim 3 and 4, wherein the section S of the length x representing the shortest distance (11) between the two slanted cylinder axes (9) runs parallel or at an angle to the longitudinal axis (4) and has a shortest distance y > 0. 6. Intramedullary nail (1) as claimed in claim 5, wherein the distance y is less than D/2. 7. Intramedullary nail (1) as claimed in claim 5 and 6, wherein the distance y is greater than 0.4 D. 8. Intramedullary nail (1) as claimed in claim land 2 wherein the, cylinder axes (9) of the two mutually penetrating drill cylinders (8) intersect at an angle ß, wherein 30° 9. Intramedullary nail (1) as claimed in claim 1, 2, and 8 wherein the distance d relative to the diameter D lies in the range 0.0001 D 10. Intramedullary nail (1) as claimed in claim 1 to 8, wherein the mutually penetrating drill cylinders (8) are provided with two separate entrance points into the intramedullary nail (1), but only one common exit from the intramedullary nail (1). 11. Intramedullary nail (1) as claimed in claim 1 to 10, wherein the diameter DB of the mutually penetrating drill cylinders (8) measures at most 0.6 times, and preferably at most 0.5 times D. 12. Intramedullary nail (1) as claimed in claim 1 to 10, wherein it is provided with a longitudinal hole (10) coaxial to the central longitudinal axis (4). 

3544DELNP2005Abstract(28112008).pdf
3544delnp2005assignment.pdf
3544DELNP2005Claims(28112008).pdf
3544DELNP2005CorresopndenceOthers(28112008).pdf
3544DELNP2005CorrespondenceOthers(04032008).pdf
3544DELNP2005CorrespondenceOthers(12122007).pdf
3544delnp2005correspondenceothers.pdf
3544delnp2005descriprion (complete).pdf
3544DELNP2005Description (Complete)(28112008).pdf
3544DELNP2005Drawings(28112008).pdf
3544DELNP2005Form1(28112008).pdf
3544delnp2005form13(04032008).pdf
3544DELNP2005Form2(28112008).pdf
3544DELNP2005Form26(04032008).pdf
3544DELNP2005Form3(28112008).pdf
3544delnp2005petition138.pdf
Patent Number  228322  

Indian Patent Application Number  3544/DELNP/2005  
PG Journal Number  07/2009  
Publication Date  13Feb2009  
Grant Date  31Jan2009  
Date of Filing  09Aug2005  
Name of Patentee  SYNTHES GMBH  
Applicant Address  EIMATTSTRASSE 3, CH4436 OBERDORF, SWITZERLAND.  
Inventors:


PCT International Classification Number  A61B 17/72  
PCT International Application Number  PCT/CH2003/000184  
PCT International Filing date  20030321  
PCT Conventions:
