HK1237291B - Injection needle - Google Patents

Description

injection needle

The present application is a divisional application of the invention patent application entitled “Injection Needle” with application number 200910206725.5 filed on October 21, 2009 and with priority date of October 28, 2008.

Technical Field

The present invention relates to an injection needle for injecting medicine into human or animal body tissue.

Background Art

During certain surgical procedures and dental treatments, patients must be given a local anesthetic. This anesthesia is limited to the target area, and in the case of dental treatment, it should be limited to the tooth being treated. Typically, the anesthetic product is administered by injection into the tissue to be anesthetized.

During the treatment of skin diseases in humans or animals, there is sometimes a need for needles designed to perform injections in a safer and less painful manner.

Furthermore, during dental treatment, anesthetic products are injected into the gums to produce an effect in the surrounding soft tissues. Therefore, a needle is required that can reach the desired anesthesia site as precisely as possible, thereby limiting the amount of anesthetic product administered.

However, regardless of the annoyance presented to the patient, the effect of the anesthetic is not always optimal, since the anesthetic product is partially distributed at a distance from the tooth to be treated rather than remaining concentrated therein. In addition, the injection needle often deflects because it deforms when penetrating tissue, especially soft tissue.

In practice, the needle according to the invention is primarily used for applying anesthetic products, but is also used for other applications, such as dermatological applications, where the problem is to deposit the drug product at a well-defined location on the human or animal body.

Among the different anesthesia techniques, the present invention is particularly concerned with intraligamentary anesthesia and troncular anesthesia performed during dental surgery.

Intraligament anesthesia involves injecting an anesthetic product into the ligament surrounding the tooth being treated. A problem with using a traditional needle for intraligament anesthesia is the difficulty of inserting the needle deeply enough into the ligament. Even with the thinnest needles, this often results in leakage of the anesthetic. To address this issue, doctors attempt to push their needle deeper, but the needle often bends, necessitating a needle replacement and reinsertion.

Troncular anesthesia is an anesthetic technique for the lower dental nerve before entering the dental channel. During the insertion of the needle into the soft tissue, especially during troncular anesthesia or local anesthesia, the needle is pushed very deep. During its insertion, the traditional needle deforms, which then leads to a curved trajectory, which makes it impossible to correctly perform the injection at the expected position. This is a factor of failure that cannot be ignored. In order to find a solution to this problem, a variety of solutions have been proposed. It should be known that most of the needles used have a diameter of 0.4 or 0.5 mm. First, it is necessary to increase the diameter of the needle to increase its rigidity. It is recommended to preferably use a diameter of 0.51 mm. Traditionally, the inner diameter of the needle is 0.25 mm. It is recommended to use the double rotation insertion technique (BRIT), which includes rotating the needle alternately half a circle in one direction and half a circle in the other direction during the insertion, which eliminates the effect of deviation. This operation is very difficult to perform, and only automatic injectors allow this.

Summary of the Invention

The object of the present invention is to propose an injection needle for administering a medicinal product, which finds a solution to overcome the above-mentioned drawbacks.

The objects of the present invention are achieved with an injection needle for injecting a medicinal product into the human or animal body, wherein the needle comprises a tubular body having two opposite ends, a first end for connection to a product supply device and a second end for piercing the human or animal body, the second end being provided with a primary bevel and a secondary bevel forming a needle tip.

According to the invention, the secondary bevel is located opposite the primary bevel and together with the primary bevel forms a single cutting edge inclined relative to the longitudinal axis of the tubular body, the cutting edges extending on either side of a median face of the primary bevel passing through the longitudinal axis of the tubular body.

Due to the relative positioning of the secondary bevel with respect to the primary bevel and the fact that the cutting edge extends on either side of the median plane of the primary bevel passing through the longitudinal axis of the tubular body, the leading end of the needle, viewed in the direction of needle penetration into the body, is formed so that the needle is subjected to mutually reducing, approximately opposing forces. Thus, needle deflection is minimized.

The advantageous effects of the injection needle according to the present invention can be further enhanced by providing the needle with at least one of the following features, considered individually or in any technically feasible combination:

The secondary bevel forms an angle of less than 10 degrees with the longitudinal axis of the tubular body;

The main bevel forms an angle of between 5 and 25 degrees with the longitudinal axis of the tubular body;

The main bevel forms an angle of between 5 and 10 degrees with the longitudinal axis of the tubular body;

The primary bevel and the secondary bevel form an angle between them of between 15 degrees and 30 degrees;

For different needle calibers, the tubular body has an inner diameter smaller than the standard value;

The needle is provided with a positioning mark which is positioned opposite the main bevel relative to the longitudinal axis of the needle.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent from the following description of a needle consisting of two exemplary embodiments, which are described with reference to the accompanying drawings, in which:

FIG1 shows a first injection needle according to the present invention in a side view viewing a secondary bevel;

FIG2 shows the first needle in a side view looking at the main bevel;

FIG3 shows the first needle in a top view looking at the main bevel;

FIG4 shows the first needle in an axial view on two bevels;

FIG5 shows a second injection needle according to the present invention in a side view viewing the secondary bevel;

Figure 6 shows the second needle in a side view looking at the main bevel;

FIG7 shows the second needle in a top view on the main bevel;

Figure 8 shows the second needle in an axial view on two bevels; and

FIG. 9 shows an injection needle with positioning marks.

DETAILED DESCRIPTION

Figures 1 to 4 show an injection needle for intraligamentary anesthesia. The needle comprises a tubular body 1 having a longitudinal axis A and two opposite ends 2, a first end 2 of which is suitable for connection to a product supply device, such as a syringe or a flexible tube (which is itself connected to a cylinder or any other type of container), or to an automatic device suitable for administering a drug in a programmable manner.

The second end portion 3 for piercing a human or animal body is provided with a primary bevel 4 and a secondary bevel 5 , which together form a single cutting edge 6 and a needle tip 7 .

The tubular body 1 of the injection needle is a substantially hollow cylinder and is symmetrical about the longitudinal axis A. Therefore, the tubular body 1 has an outer diameter E1 and an inner diameter L1. While the outer diameter E1 represents the caliber of the injection needle, the inner diameter L1 represents the size of the lumen of the tubular body 1 through which the drug can pass during injection.

Injection needles used for intraligamentary anesthesia in dental surgery are made of tubing with an outer diameter of 0.3 mm. According to the present invention, this tubing is provided at the end intended for puncturing the human or animal body. It has a primary bevel 4 and a secondary bevel 5 positioned opposite each other, with a relatively small angle D between the two bevels. In this way, the intersection of bevels 4 and 5 creates an inclined cutting edge 6 relative to the longitudinal axis A of the needle's tubular body 1. The orientation of the cutting edge 6 depends primarily on the relative orientation of the two bevels. As the angle D between the bevels increases, this orientation relative to the axis A of the tubular body 1 deviates further and further from a perpendicular configuration.

However, the orientation of cutting edge 6 also depends on the angle that each of the two bevels forms with the longitudinal axis A of tubular body 1. In the case of an injection needle for intraligamentary anesthesia, angle B between primary bevel 4 and longitudinal axis A, as well as angle C between secondary bevel 5 and longitudinal axis A, are at least approximately equal and as small as possible given the technical manufacturing constraints. By making angles B and C less than 10° relative to longitudinal axis A, a very flat needle is produced that can be deeply inserted into the ligament.

At the same time, the small angles between each of the two bevels 4 and 5 and the longitudinal axis A (in particular the small angle C between the secondary bevel 5 and the longitudinal axis A) can only be achieved by using special tubes with thicker walls than in the case of tubes according to the ISO 9626 standard, which sets the following values, for example:

To manufacture a needle according to the present invention, the secondary bevel 5 can be brought closer to the longitudinal axis A of the tubular body 1 by using a tube with thicker walls (because it has a reduced inner diameter L1 relative to a standard needle), i.e., by reducing the diameter of the lumen of the needle, which reduces the length of the lumen at the end 3 of the needle.

In this way, for example, an injection needle can be given the following properties:

Furthermore, the angle C between the secondary bevel 5 and the longitudinal axis A can be reduced relative to conventional needles. A similar concept applies to the orientation of the primary bevel 4 and the angle B1 formed with the longitudinal axis A. In the exemplary embodiment shown in Figures 1 to 4, the angles B1 and C are equal with the same tolerance and have a value of 7°±1°.

The injection needle according to the present invention, which can be used for intraligamentary anesthesia, has two main advantages. First, the blade-shaped tip of the needle allows deeper penetration into the tissue. This reduces leakage during injection and minimizes the lateral component of the resistance encountered by the needle during deeper penetration. Furthermore, by using a thicker-walled needle, the person or animal being treated benefits from a more rigid tube, making the needle less susceptible to deformation, significant bending, and deflection from the primary source associated with conventional needles.

In summary, the needle according to the present invention is improved over conventional needles in two different aspects, each of which contributes independently to increasing the linearity of the insertion path.

In order to fully realize the advantages provided by the present invention, the needle according to the present invention is advantageously provided with a positioning mark M as shown in FIG9 on the needle base 8 that receives the tubular body. This mark is located on the back of the needle relative to the main bevel 4. This allows the practitioner to know that the main bevel of the needle is actually parallel to the mucosa.

When the injection needle according to the present invention is applied to troncular anesthesia (i.e., for depositing drugs and the anesthetic drug is significantly close to the nerve trunk), a 25 caliber needle (i.e., with an outer diameter of 0.5 mm) is conventionally used. However, in order for these needles to benefit from the configuration of the present invention, they are made of a tube with an inner diameter of only about 0.20 mm. As a result, the needle has a thicker wall than that of a standard needle. The increase in the needle wall thickness first strengthens its rigidity and, therefore, reduces its bending when piercing the tissue. Next, by increasing the wall thickness, the secondary bevel can be brought closer to the longitudinal axis A of the tubular body 1 without penetrating the lumen.

Thus, for the injection needle manufactured according to the second exemplary embodiment shown in Figures 5 to 8, its basic configuration is again found to be the same as described with reference to the first exemplary embodiment.

However, since the needle according to the second exemplary embodiment has a larger caliber E2 than the caliber E1 of the needle of the first exemplary embodiment, and since the inner diameter L2 is correspondingly and to a lesser extent larger than the inner diameter L1 of the needle of the first exemplary embodiment, the main bevel 41 of the needle according to the second exemplary embodiment cannot have the same small angle as the main bevel according to the first exemplary embodiment. Therefore, the angle B2 formed by the main bevel 41 together with the longitudinal axis A is approximately 20° to 25°, for example, 21°±1°.

In contrast, the angle C formed by the secondary bevel 51 together with the longitudinal axis A of the catheter 1 is the same as the angle C of the needle according to the first exemplary embodiment, i.e., less than 10°, preferably 7°±1°. Thus, for the secondary bevel 5 according to the first exemplary embodiment and the secondary bevel 51 according to the second exemplary embodiment, an angle C formed together with the longitudinal axis A of up to 6° can be achieved.

Although the primary and secondary bevels of the needle according to the second exemplary embodiment do not have the same small angles as according to the first exemplary embodiment, the end of the needle is still subjected to almost equal opposing forces, with a significantly smaller lateral component, which significantly reduces the risk of deviation of the needle when penetrating tissue of the human or animal body.

Claims (5)

1. An injection needle for injecting a drug into tissue of a human or animal body, the injection needle comprising: a tubular body (1) having two opposing ends (2, 3), the two opposing ends including a first end (2) for connection to a product supply device and a second end (3) for insertion into the human or animal body, the second end (3) being provided with a primary bevel (4) and a secondary bevel (5), characterized in that the injection needle is a flat needle having a leaf-shaped second end (3), the second end (3) having a... The primary bevel (4) and the secondary bevel (5) form a single, continuous straight cutting edge (6) extending on both sides of the middle surface of the primary bevel (4) through the longitudinal axis (A) of the tubular body (1). The injection needle is adapted for deep insertion into the human or animal body. The primary bevel (4) and the secondary bevel (5) are positioned relative to each other such that the lateral components of the resistance acting on the injection needle during tissue insertion cancel each other out to achieve a substantially linear trajectory during deep tissue insertion. The main inclined plane (4) and the secondary inclined plane (5) form an angle between 15 degrees and 30 degrees. 2. The injection needle according to claim 1, characterized in that the main bevel (4) and the secondary bevel (5) of the injection needle used for intraligament anesthesia each have an angle of less than or equal to 10 degrees relative to the longitudinal axis (A) of the injection needle. 3. The injection needle according to claim 2, characterized in that the angles of the main inclined plane (4) and the secondary inclined plane (5) relative to the longitudinal axis (A) of the injection needle are substantially equal. 4. The injection needle according to claim 1, characterized in that the angle formed between the main inclined plane (4) of the injection needle for troncular anesthesia and the longitudinal axis (A) of the injection needle is between 20 degrees and 25 degrees, and the angle formed between the secondary inclined plane (5) and the longitudinal axis (A) of the injection needle is less than 10 degrees. 5. The injection needle according to any one of claims 1-4, characterized in that the tubular body (1) has a wall thicker than that of a standard tube to achieve the angle formed by the secondary bevel (5) and the longitudinal axis (A) of the injection needle and the angle formed by the primary bevel (4) and the longitudinal axis (A) of the injection needle.