CZ297594A3 - Tool for drilling, particularly of biological materials - Google Patents

Abstract

This drilling tool particularly for biomaterials consists of a cylindrical beam (1) with a conical end (2); the face area (6,7) of each of the main blades (3,4) is geometrically created exclusively by a linear movement forming a plane curve (8) turned in the area passing through the longitudinal axis of the beam (1) and the side point (9) of the main blade (12, 13) by an angle (ω) towards the horizontal axis of the beam (1) and declined towards this area by an angle (φ) so that the main cutting blades (12,13) are created by the crossing of this front area (6,7) with the plane back area (10,11) forming the closing lines of these front areas (6,7) and the back areas (10, 11).<IMAGE>

Description

Technical field

The invention relates to a tool for drilling biomaterials for external transosseal skeletal fixation in orthopedics.

BACKGROUND OF THE INVENTION

Currently, special wires - Kirschner wires, respectively - are used for external transosseal skeletal fixation. called K-wires, in which the front part (tip) is shaped as a cutting tool. These tools are designed to drill bones and stabilize the limb during treatment. ~

This treatment method is one of the basic and frequently used in orthopedic, surgical and traumatological practice.

Kirscher wires are used primarily as single-purpose tools that are not used multiple times. In many cases, they become deformed, essentially depreciated during treatment, or shortened to the minimum length required by individual requirements.

So far, the technology of drilling small bone holes, up to 3 mm in diameter, for the introduction of fixation beams has not been satisfactorily solved. The disadvantages of the current technology are mainly due to too long and physically strenuous surgery during surgery, where the risks of infection and anesthesia increase. Existing cutting parts utilize various variations of commonly known drill tool shapes. For example, a conventional drill bit; the trocar, or the so-called three-surface or four-surface pyramidal tip - the cylindrical end is ground into planar surfaces forming cutting edges; a bayonet-like tip, or a so-called half drill, where the tool is tapered and ground longitudinally to half the diameter of the cylindrical portion, often in a two-stage design;

drill with straight groove - two longitudinal grooves cut to a depth equal to the radius of the cylindrical part.

predominantly negative geometry a number of negative phenomena. Include mechanical delay and devastation of it

These tools are characterized by a cutting edge, resulting in among the most well known negative phenomena of the drilled hole; thermal necrosis and pressure necrosis; bone defect healing; low tool targeting resulting in susceptibility to tool down from drilled bone surface, pushing bone fragments in front of drill bit; low comfort of the surgeon during the drilling, i.e. the difficulty and effort of the operation; increased consumption of antibiotics, anesthetics; postoperative complications.

Some of these drawbacks are partly addressed by the use of twist drills that are capable of drilling with less energy consumption, but which are particularly marked by drawbacks such as the high cost of tools - up to ten times higher than the conventional tools listed above. Furthermore, there is an increased susceptibility to soft tissue winding, there is a particularly high risk of drilling near the nerves.

SUMMARY OF THE INVENTION

These shortcomings. are a substantial tool for drilling, in particular biomaterials, consisting of a cylindrical beam with a conical end provided at its one end with two symmetrical main cutting edges which form an apex angle according to the invention. Its essence is that the apex angle between the main cutting edges is in the shorter direction in the range of 50 ° to 90 °. Furthermore, the beam is provided with one connecting lip between the main cutting edges. The front face of each of the major cutting edges is geometrically formed solely by a linear motion forming planar curves rotated in a plane passing through the longitudinal axis of the beam and the edge point of the main cutting edge at an angle MJ of 60 ° to 85 ° relative to the longitudinal axis of the beam. plane by another angle V of 5 ° to 30 °. By intersecting this face with the planar dorsal surface, the intersection of these faces and the dorsal surfaces of the main cutting edges are formed. The connecting edge is formed by the intersection of the dorsal surfaces of the two main cutting edges and the edge edge of the main cutting edge on the outside diameter has a positive rake angle in the side, rear and orthogonal plane between 1 ° and 30 °. .

The cylindrical beam is preferably provided with an external thread.

The basic advantages of this tool include the positive geometry of the front and back angles of the cutting edges, creating sharp cutting edges practically along the entire length of the cutting edges in the orthogonal, lateral and rear planes. Another advantage is the low energy effort exerted by the surgeon during drilling and the easy targeting, centering, tooling and thus the possibility of drilling bones. under. angle without tendency to slip .. tools. Other advantages include favorable drilling accompanying phenomena, such as satisfactory drilling of bone crumb, shortening of drilling time and elimination of pressure and thermal necrosis. Last but not least. the low tendency to soft-wind is also an important factor. weaving. The biomaterial drilling tool of the present invention is easy to manufacture, while maintaining favorable manufacturing costs.

Although it is a single-purpose tool, mostly for single use, preliminary tests have proven the ability to re-use under normal operating conditions for many biomaterials. It is possible to use up to 20 times without significant loss of cutting.

BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS The invention and its advantages will be explained in more detail with reference to the drawing, in which an exemplary biomaterial drilling tool according to the invention is shown in FIG. FIG. 2 shows the tool in side view and FIG. 3 in plan view. Fig. 4 is a cross-sectional view taken along line A-A in Fig. 1;

DETAILED DESCRIPTION OF THE INVENTION

The invention is described in more detail by means of one possible specific exemplary embodiment, shown in the accompanying drawing.

An exemplary biomaterial drilling tool consists of a beam 1 and a cylindrical shape with a tapered end 2. On the tapered end 2, two symmetrical main cutting edges 3,4 are formed, forming an apex angle of 75 ° and one connecting lip 5. The main cutting edges 3, 4 are geometrically formed by a linear movement forming planar curves 8, rotated, in a plane passing through the longitudinal axis of the beam 1 and the edge point 9 of the main cutting edge 12.13 at an angle W of 75 ° to the longitudinal axis of the beam 1. an angle ψ 20 ° such that the intersection of the front surface 6,7 with the planar dorsal surface 10,11 is formed by the intersection of these front surfaces 6, 7. and planar dorsal surfaces 10.11 main cutting edges 12.13. The connecting blade 14 is formed by the intersection of the dorsal surfaces 10, 11. Both the main cutting edges 3,4 and the edge point 9 of the main cutting edge 12.13 on the outer diameter of the beam 1 have a positive rake angle in the side, rear and orthogonal planes and a positive rake angle measured in these planes.

A thread (not shown here) has been formed on the beam 1. The thread enables better drilling of the drilled bone chippings and can be used for a certain prestressing.

Example

The pig's cortical long bone drilling tool has been manufactured with the following geometry:

diameter of cylindrical beam 1 1,8 mra apex angle between main cutting edges 3,4 70 'radius of the bottom forming plane curves 0,4 mm left side forming plane curves from horizontal direction 20 ° right side forming plane curves from horizontal direction 90 ° angle UJ 70 ° angle 15 '

This tool has repeatedly achieved the lowest forces required to push the tool into the cut and to rotate the tool while drilling relative to the other cited tools under the same cutting conditions on the same material. On a relative comparison, this difference ranged from 30 to 200%. The drilled tissues, in this case the bones, showed practically no signs of thermal or mechanical necrosis. , · ...

Industrial Applicability i

The tool for drilling, in particular biomaterials according to the invention, is particularly useful in hospitals and veterinary facilities.

Claims (2)

PATENT CLAIMS A tool for drilling, in particular biomaterials, consisting of a beam of cylindrical shape, with a conical end, provided at one end with two symmetrical main cutting edges which form an apex angle, characterized in that the apex angle between said main cutting edges (3,4) is in a shorter direction in the range of 50 to 90 and further, the beam (1) is provided with one connecting lip (5) between the main cutting edges (3,4), the front surface (6,7) of each of the major cutting edges (3,4) being geometrically formed exclusively by linear movement forming V-shaped planar curves (8) rotated in a plane passing through the longitudinal axis of the beam and the edge point (9) of the main cutting edge (12,13) by an angle (UJ) in the range 60 'to -85' relative to the longitudinal axis of the beam (1), measured in a shorter direction, and inclined with respect to this plane by another angle (θ) in the range of 5 to 30, intersecting this face (6,7) with the plane dorsal the surface (10, 11) are formed by the intersection of the front surfaces (6,7) and the dorsal surfaces (10,11) of the main cutting edge (12,13) and the connecting blade (14) is formed by the intersection of the dorsal surfaces (10,11) the main cutting edge edge (9) of the main cutting edge (12, 13) at the outer diameter has a positive rake angle in the side, rear and orthogonal planes in the range of 1 to 30 and a positive rake angle in these planes in the range 0 to 20 May Tool according to claim 1, characterized in that the cylindrical-shaped support (1) is threaded.