SYRINGE AND RELATIVE NEEDLE
TECHNICAL FIELD
The present invention concerns a needle for a syringe (in particular for biopsies), a syringe (in particular for biopsies) and a method for manufacturing a needle.
BACKGROUND OF THE INVENTION
With particular reference to figure 2, syringes for biopsies are currently marketed comprising a needle with a cannula having a penetration end provided with three points and three troughs which alternate with the three points. Between the points and along each trough, three blades are defined, which allow partial cutting of a biological tissue so that a portion (sample) of the biological tissue is inserted inside the needle and can therefore be removed. In the area of the bottom of the troughs, the blades have a rounded profile.
Although this type of syringe (normally identified as "Franseen") is currently used, it has been experimentally observed that the force required for insertion of the needle into the biological tissue is relatively high and that the biological tissue is not always precisely cut, since it is partially torn during insertion.
Some types of needles are described in the patent documents WO2008/023193, US3289675, US2007 / 0078415 , US5423330. In particular, WO2008/023193 describes a medical device for taking biological samples, said device comprising an elongated housing, a probe for sampling the biological material and a current supply electrically coupled with the probe or with the elongated housing.
The object of the present invention is to provide a needle for a syringe (in particular for biopsies), a syringe (in particular for biopsies) and a method for manufacturing a needle which overcome, at least partially, the drawbacks of the known art and are, at the same time, easy and inexpensive to produce. SUMMARY
According to the present invention, a needle for a syringe (in particular for biopsies), a syringe (in particular for biopsies) and a method for manufacturing a needle are provided as claimed in the following independent claims and, preferably, in any one of the claims depending directly or indirectly on the independent claims.
BRIEF DESCRIPTION OF THE FIGURES
The invention is described below with reference to the attached figures, which illustrate some non-limiting embodiment examples, in which:
- figure 1 is a perspective view of a point of a needle manufactured according to the present invention;
- figure 2 is a perspective view of a point of a needle of the state of the art;
- figure 3 illustrates schematically a step of a method according to the present invention for manufacturing the needle of figure 1;
- figure 4 is a perspective view of the point of the needle obtained following the work step of figure 3;
- figure 5 is a lateral view of the point of the needle of figure 4;
- figure 6 is a front perspective view of the point of the needle of figure 4;
- figure 7 illustrates schematically a step of the method of figure 3 after the work step of figure 3;
- figure 8 is a perspective view of the point of the needle obtained following the work step of figure 7;
- figure 9 is a front perspective view of the point of the needle of figure 8;
- figures 10 and 11 are perspective views relative to an alternative embodiment of a method for manufacturing the needle of figure 1;
- figures 12 and 13 are lateral schematic views of the illustrations of figures 10 and 11 respectively;
- figure 14 is a schematic perspective view of a tool used in the method of figures 10 to 13;
- figures 15 and 16 are perspective views of two different embodiments of a point of a needle produced according to the present invention; and
- figure 17 is a graph relative to experimental penetration tests performed with a needle of the state of the art ( "Franseen" ) ; the X axis indicates the penetration depth (point 0 indicates that the needle points are at 0 mm from the surface of the tissue to be penetrated, the maximum value indicates the stroke end of the penetration) , and the Y axis indicates the values corresponding to the penetration force in N;
- figure 18 is a graph relative to experimental penetration tests performed with a needle according to the present invention; the X axis indicates the penetration depth (the point 0 indicates that the needle points are at 0 mm from the surface of the tissue to be penetrated, the maximum value indicates the stroke end of the penetration) , the Y axis indicates the values corresponding to the penetration force in N; and
- figure 19 is a perspective view of a syringe (for biopsies) according to the present invention.
DETAILED DISCLOSURE
In figure 1 the number 1 indicates as a whole a needle for syringe (in particular for biopsies) . The needle 1 comprises a cannula 2 having a penetration end 3 provided with at least one point 4, at least one trough 5 and at least one blade 6. In particular, the cannula 2 comprises a perimeter wall which delimits an inner lumen of the cannula 2. The end 3 can be opened so as to establish communication between the above- mentioned lumen and the outside.
According to the embodiment illustrated in figure 1, the penetration end 3 is provided with three points 4, three troughs 5 and three blades 6.
The (each) trough 5 has a bottom 7 with a V-shaped profile (with an edge; in particular, with a sharp non-rounded edge) . The (each) blade 6 extends through the (respective) bottom 7.
Advantageously, the blade 6 comprises a portion 8 arranged in the area of the point 4 (in particular, of one of the points 4) , a portion 9 arranged in the area of the trough 5 so as to delimit on a first side the relative bottom 7, a portion 10 arranged in the area of the trough 5 so as to delimit on a second side the relative bottom 7, and a portion 11 arranged in the area of the point 4 of another of the points 4. In particular, each blade 6 extends between two respective points 4 through the relative bottom 7. More precisely, each blade 6 extends from one of the points 4 to another of the points 4 through the relative bottom 7. In particular, the blade 6 consists of the first portion 8, the second portion 9, the third portion 10 and the fourth portion 11.
According to some embodiments, each portion 8, 9, 10 and 11 is delimited (in particular, laterally towards the outside of the cannula 2) by a respective sharpening surface 12, 13, 14 and 15, which is inclined relative to a longitudinal axis A of the cannula 2 (more precisely, relative to a direction parallel to the axis A) . In particular, the sharpening surfaces 12, 13, 14 and 15 all have the same inclination relative to the axis A (more precisely, relative to the direction parallel to the axis A) . In greater detail, the sharpening surfaces 12, 13, 14 and 15 have an inclination at an angle A' ranging from 10° to 20° (more precisely, from 12° to 16°) relative to the axis A (more precisely, relative to the direction parallel to the axis A) .
In figure 1, an embodiment is shown according to which the sharpening surfaces 12, 13, 14 and 15 have an inclination of 14° (angle A') relative to the axis A (more precisely, relative to the direction parallel to the axis A) . Said inclination is shown more clearly in figure 5, which is relative to the end 3 only partially machined.
The sharpening surfaces 13 and 14 are inclined relative to each other and relative to the sharpening surfaces 12 and 15 respectively. In particular, in this way the cannula 2 has a reduced thickness (a depression) in the area of the bottom 7.
According to some embodiments, the sharpening surfaces 13 and
14 are inclined relative to each other at an angle B ranging from 120° (in particular, from 130°) to 160° (in particular, to 150°) . According to some variations, sharpening surfaces 13 and 14 are inclined relative to the sharpening surfaces 12 and
15 respectively at relative angles C ranging from 190° (in particular, from 195°) to 210° (in particular, to 205°) . Advantageously, the sharpening surfaces 12 and 15 lie on the same plane. In particular, the sharpening surfaces 13 and 14 lie on respective planes inclined relative to each other and relative to the plane of the sharpening surfaces 12 and 15.
In particular, the sharpening surfaces 12, 13, 14 and 16 are (each) substantially flat.
Advantageously, the sharpening surfaces 13 and 14 are inclined relative to each other and relative to the sharpening surfaces 12 and 15 respectively so as to define on the cannula 2 a concavity facing outwards (of the cannula 2) .
In particular, the sharpening surfaces 13 and 14 are joined in the area of the relative bottom 7 by means of a joining line 7' inclined relative to the longitudinal axis A of the cannula 2 (more precisely, relative to the direction parallel to the axis A) .
According to some embodiments (like those illustrated), the portions 8 and 9 are joined together by means of a joining line inclined relative to the axis A.
Advantageously, the portions 10 and 11 are joined to each other by means of a joining line inclined relative to the axis A.
The cannula 2 has a cylindrically shaped outer surface (which externally delimits the cannula 2) which extends parallel to the axis A and is inclined (by the angle A' ) relative to the sharpening surfaces 11, 12, 13, 14 and 15. Advantageously, all the blades 6 are as defined above and therefore have respective portions 8, 9, 10 and 11 as described above.
According to some embodiments (like the one illustrated in figure 15), the penetration end 3 is provided with at least one second point 4, at least one second trough 5, and at least one second blade 6. In particular, each trough 5 is arranged between two points and has a respective bottom 7 with a V- shaped profile (not rounded) .
Figure 15 illustrates an embodiment substantially identical to the embodiment of figure 1, from which it differs exclusively due to the fact that the end 3 is provided with (at least) two points 4, two troughs 5 and two blades 6.
According to some embodiments (like the one illustrated in figure 1), the penetration end 3 is provided with at least one third point 4, at least one third trough 5 and at least one third blade 6; in particular, the first blade 6 extends from the first point 4 to the second point 4 through the relative bottom 7, the second blade 6 extends from the second point 4 to the third point 4 through the relative bottom 7, and the third blade 6 extends from the third point 4 to the first point 4 through the relative bottom 7.
Figure 16 depicts an embodiment substantially identical to the embodiment of figure 1, from which it differs exclusively due to the fact that the end 3 is provided with one single point 4 and one blade (instead of three) .
Advantageously, the cannula 2 is made of stainless steel. In particular, the cannula 2 is made of steel selected from the group consisting of: AISI 304, AISI 316 (and a combination thereof) . According to preferred embodiments, the cannula 2 has an external diameter (i.e. which also includes the thickness of the perimeter wall) up to 2.2 mm (in particular, up to 1.5 mm) . In some cases, the external diameter is at least 0.8 mm (in particular, at least 0.9 mm) . More precisely, the external diameter ranges from 0.9 mm to 2.15 mm.
According to some embodiments, the cannula 2 has an external diameter (i.e. which also includes the thickness of the perimeter wall) up to 1.4 mm (in particular, up to 1.3 mm) . In some cases, the external diameter is at least 1.1 mm (in particular, at least 1.2 mm) . More precisely, the external diameter ranges from 1.2 mm to 1.3 mm.
According to preferred embodiments, the cannula 2 has an internal diameter (i.e. the diameter of the internal lumen of the cannula 2 without considering the thickness of the perimeter wall) up to 2.5 mm (in particular, up to 2 mm) . In some cases, the internal diameter is at least 0.4 mm (in particular, at least 0.45 mm) . More precisely, the external diameter ranges from 2 mm to 0.45 mm .
According to some embodiments, the cannula 2 has an internal diameter (i.e. the diameter of the internal lumen of the cannula 2 without considering the thickness of the perimeter wall) up to 1.2 mm (in particular, up to 1.15 mm) . In some cases, the internal diameter is at least 0.6 mm (in particular, at least 0.7 mm) . More precisely, the external diameter ranges from 0.7 mm to 1.15 mm.
Typically, the perimeter wall has a thickness ranging from 0.8 to 1.2 mm (in particular, approximately 0.1 mm) .
In accordance with a second aspect of the present invention, a syringe 16 is provided (in particular for biopsies) (figure 19) comprising a needle 1 as defined above.
In accordance with a third aspect of the present invention, a method is provided for manufacturing a needle as defined above.
Referring in particular to the figures from 3 to 9 and from 10 to 13, the method comprises a first step of machining the penetration end 3 of the cannula 2, during which at least one tool 17 of an electro discharge machine (EDM) , which comprises an electro discharge element 18 with a triangular cross section, is used. In particular, the electro discharge element 18 has the shape of a prism (right) with triangular base (cross section) .
The tool 17 is brought into contact with the cannula 2 in a first area of an end 3 of the cannula 2 so that a point of the electro discharge element 18 faces the cannula 2 (comes into contact with the cannula 2) and makes the bottom of the first trough 5. In particular, the electro discharge element 18 makes the sharpening surfaces 13 and 14.
In the embodiments illustrated in the figures from 10 to 13, the tool 17 also comprises a further electro discharge element 19 provided with two electro discharge surfaces 20 (flat) arranged on opposite sides of the electro discharge element 18 which projects from the electro discharge element 19 (and is integral with said electro discharge element 19) . In particular, the electro discharge element 19 makes the sharpening surfaces 12 and 15. More precisely, the electro discharge element 19 has the shape of a prism (right) with rectangular base (section) .
Figures 8 and 9 illustrate the end 3 after the first machining step using the tool 17 of figures 10 to 14.
With particular reference to figure 14, it should be noted that the electro discharge element 18 has its own electro discharge surfaces 21 adapted to come into contact with the cannula 2. Advantageously, the electro discharge surfaces 21 are inclined relative to one another at an angle D ranging from 200° to 240°.
According to some variations, discharge surfaces 21 are inclined relative to the respective electro discharge surfaces 20 with relative angles E ranging from 150° to 170°.
In figures 3 to 9 a different embodiment is shown from that of figures 10 to 13, from which it differs due to the fact that the electro discharge elements 18 and 19 are separate from each other. First the electro discharge element 18 is used (figure 3) and then the electro discharge element 19 (figure 7) . Advantageously, in this case, the electro discharge element 19 has one single electro discharge surface 20 (flat) . Figures 4 to 6 illustrate the end 3 after the action of the electro discharge element 19.
According to some embodiments (in particular, those via which the ends 3 illustrated in figures 1 and/or 15 can be obtained), after the first work step, the cannula 2 and the electro discharge element 18 (or tool 17) are separated. At this point, the cannula 2 and the electro discharge element 18 (or tool 17) are rotated relative to each other (by 180°, to obtain the end 3 illustrated in figure 15, or by 120°, to obtain the end illustrated in figure 1) . In particular, the cannula 2 is rotated about its longitudinal axis A. According to some embodiments, the method comprises a second work step of the penetration end 3 of the cannula 2, during which the tool 17 of the electro discharge machine is brought into contact with the cannula 2 in a second area of the end 3 different from the first area so that the point of the electro discharge element 18 faces the cannula 2 (comes into contact with the cannula 2) and makes the bottom of the second trough 5.
In particular, after the second work step, the cannula 2 and the electro discharge element 18 are separated. At this point, the cannula 2 and the electro discharge element 18 are rotated relative to each other (by 120° to obtain the end illustrated in figure 1) . In particular, the cannula 2 is rotated about its longitudinal axis A. Advantageously, the method comprises a third work stage of the penetration end 3 of the cannula 2, during which the tool 17 of the electro discharge machine is brought into contact with the cannula 2 in a third area of the end 3 of the cannula 3 different from the first and the second area so that the point of the electro discharge element 18 faces the cannula 2 (comes into contact with the cannula 2) and makes the bottom of the third trough 5.
Advantageously, during the first work step (and if necessary also the second and third work step) the electro discharge surface/s 20 is/are inclined relative to the direction of the axis A of the angle A' .
Advantageously, during the first work step (and if necessary also the second and third work step) the electro discharge surfaces 21 are inclined relative to the direction of the axis A of the angle A' .
According to some variations, the end 3 is obtained by means of laser machining. Alternatively or in addition, the needle 1 and, more precisely, the end 3 are obtained by means of 3d (three- dimensional) printing.
Further characteristics of the present invention will become clear from the following description of a merely illustrative and non-limiting example.
Example
To determine the penetration efficiency of the needle developed, a series of comparison tests with the standard Franseen needle were performed.
These tests were performed by mounting a needle as described above (figure 1) on a high precision load cell, which in turn had been mounted on an electric cylinder. The load cell has a utilization range from 0 N to 44.5 N, with a precision of approximately 0.001 N.
The following instruments were used: load cell FUTEK model FSH00104 with relative adapter USB210 model FSH03221 and relative control software SENSIT model FSH03189. Electric cylinder SMC model LEY32A-100C-R36P1D with relative programming software and PC connection cable model LEC-W2.
The equipment composed as above allowed the perforation of a given reference material (carrot, which has a consistency similar to the prostate) , which had been positioned at the base of the bench, using an adjustable thrust of the piston, and determination, via the load cell sensing, of the quantity of force required for the point to penetrate the reference material. The thrust force and acceleration of the piston were maintained unchanged for all the tests performed: a total stroke of 60 mm (starting from at least 10 mm distance from the surface to be perforated to have a constant speed along the entire perforation), an acceleration of 3000 mm/sec2, a constant speed of 500 mm/s and a thrust force of 85N (the minimum that can be set on the cylinder) . A cylinder movement speed of 500 mm/s was used.
The data acquisition process entailed the following operations, once the bench was equipped: the load cell reading was started (for 10 seconds) and then the electric motor start command was pressed to perform the perforation. After the 10 second load cell reading, the load cell SENSIT software generated an Excel sheet with the values detected. It was then our job to manually eliminate all the values prior to switch-on of the electric cylinder and after the stroke end of the cylinder. To summarise, the values used to produce the graphs originate from the load cell control software. These files were then processed and simplified to eliminate all the negligible values, i.e. the forces measured prior to penetration (constantly around 0.0 N) and those recorded after the stroke end of the cylinder. Figure 17 illustrates the graphs relative to the values measured for the standard Franseen type needle.
Figure 18 illustrates the graphs relative to the values measured for the needle as described above according to the present invention . For both figures 17 and 18, the X axis indicates the penetration depth in mm (the point 0 indicates that the needle points are at 0 mm from the surface of the tissue to be penetrated, the maximum value indicates the penetration stroke end) , and the Y axis indicates the values corresponding to the penetration force in N.
As can be noted by comparing the graphs of figures 17 and 18, while the Franseen needle in ten tests obtained force values ranging from a minimum of 12 N to a maximum of almost 21 N, the new needle in the same conditions penetrates with a force ranging from 7 N to 12 N.
In addition to demonstrating that the new needle requires a penetration force 43% lower than the Franseen needle, it can be seen that the force used is much more constant in all the tests performed, having a range of 5 N between the lowest force and the highest force measured, whereas with the Franseen needle there is a variability in the force of almost 10 N.