NEEDLE ATTACHMENT FOR A SPINAL NEEDLE

Abstract

A cannula attachment for a spinal cannula that can be used, for example, in spinal anesthesia. The cannula attachment has a body that extends between a proximal end and a distal end, a fluid channel that extends through the body, and an observation channel section visible from the outside through a transparent region of the body. At least one optical lens is arranged in the transparent region by which the observation channel section is visible with optical magnification. The observation channel section contains at least one optical prism configured for refraction and/or reflection of light incident into the observation channel section through the optical lens.

Claims

1. A cannula attachment for a spinal cannula, the cannula attachment comprising: a body which extends between a proximal end and a distal end; a fluid channel which extends through the body and which has an observation channel section visible from outside the body through a transparent region of the body; at least one optical lens which is arranged in the transparent region and by which the observation channel section is visible with optical magnification; and at least one optical prism is present in the observation channel section and configured for refraction and/or reflection of light incident into the observation channel section through the at least one optical lens.

2. The cannula attachment according to claim 1, wherein the at least one optical lens and the at least one optical prism are formed by a transparent wall of the body and are integrally joined, the at least one optical lens being assigned to an outer face of the transparent wall and the at least one optical prism being assigned to an inner face of the transparent wall.

3. The cannula attachment according to claim 1, wherein the fluid channel has a total volume, and wherein the observation channel section occupies a predominant volume fraction of the total volume.

4. The cannula attachment according to claim 1, wherein the fluid channel has a maximum internal diameter which is not more than 45% greater than a maximum internal diameter of the observation channel section.

5. The cannula attachment according to claim 1, wherein the proximal end of the body has a standardized fluid connector having a standardized internal diameter, and wherein a maximum internal diameter of the observation channel section is not more than 45% smaller than the standardized internal diameter of the fluid connector.

6. The cannula attachment according to claim 1, wherein the at least one optical lens comprises at least two optical lenses and the at least one optical prism comprises at least two optical prisms, the at least two optical lenses and the at least two optical prisms forming lens-prism pairs that are arranged angularly offset to each other in a circumferential direction of the observation channel section.

7. The cannula attachment according to claim 6, wherein a first lens-prism pair of the lens-prism pairs is arranged on a first face of the body, and a second lens-prism pair of the lens-prism pairs is arranged on a second face of the body.

8. The cannula attachment according to claim 1, wherein the body has a cuboid shape in a region of the observation channel section with a plurality of opposite outer faces, the at least one optical lens being assigned to one of the plurality of opposite outer faces.

9. The cannula attachment according to claim 1, wherein the body is made of a transparent plastic material in one piece.

10. A spinal cannula comprising: a cannula attachment according to claim 1; and a hollow needle fixed to the cannula attachment.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Further advantages and features of the invention will become apparent from the following description of a preferred embodiment of the invention that is illustrated by means of the drawings.

[0017] FIG. 1 shows a schematic top view of one embodiment of a spinal cannula according to the invention comprising one embodiment of a cannula attachment according to the invention and comprising a hollow needle fixed to the cannula attachment,

[0018] FIG. 2 shows a schematic perspective view of the cannula attachment as viewed facing a distal end,

[0019] FIG. 3 shows a further schematic perspective view of the cannula attachment as viewed facing a proximal end,

[0020] FIG. 4 shows a schematic rear view of the cannula attachment as viewed in the distal direction,

[0021] FIG. 5 shows a schematic side view of the cannula attachment,

[0022] FIG. 6 shows a schematic longitudinal section of the cannula attachment along a section VI-VI as per FIG. 5,

[0023] FIG. 7 shows a schematic plan view of the cannula attachment and

[0024] FIG. 8 shows a further longitudinal section of the cannula attachment along a section VIII-VIII.

DETAILED DESCRIPTION

[0025] According to FIG. 1, a spinal cannula S is intended for use in spinal anaesthesia and comprises a hollow needle K and a cannula attachment 1.

[0026] The hollow needle K is designed in a manner known to a person skilled in the art and is intended for puncture of the spinal cord. In this respect, the hollow needle K is elongate between a proximal end which is not further identified and a distal end E, the latter being provided with a sharpened cannula tip. The proximal end of the hollow needle K is fixed in a receiving recess A (FIGS. 6 and 8) of the cannula attachment 1 in a manner known to a person skilled in the art. For example, the proximal end of the hollow needle K can be bonded into the receiving recess A.

[0027] The cannula attachment 1 can also be referred to as a cannula hub or hub and comprises a body 2 which extends between a proximal end 3 and a distal end 4. Furthermore, the cannula attachment 1 comprises a fluid channel 5 which extends through the body 2 and which has an observation channel section 6. The observation channel section 6 is visible from the outside through a transparent region 7 (FIG. 2) of the body 2. Furthermore, the cannula attachment 1 comprises at least one optical lens 8 arranged in the transparent region 7. By means of the optical lens 8, the observation channel section 6 is visible from the outside with optical magnification.

[0028] When using the spinal cannula S, the spinal cord is punctured by means of the hollow needle K. To monitor the correct position of the distal end E in the region of the spinal cord, cerebrospinal fluid (CSF) is aspirated through the hollow needle K into the cannula attachment 1. Once there is a corresponding fluid flashback in the proximal direction, a correct position of the distal end E can be assumed. The observation channel section 6 arranged in the transparent region 7 allows visual monitoring of said fluid flashback. The at least one optical lens 8 supports the visual monitoring by means of optical magnification of the observation channel section 6.

[0029] In order to allow further improved visual monitoring, the cannula attachment 1 also comprises at least one optical prism 9, which is shown by means of FIGS. 4, 6 and 8. The optical prism 9 is arranged in the observation channel section 6 and is configured for refraction and/or reflection of light incident into the observation channel section 6 through the transparent region 7 and/or the optical lens 8. Because of its light-refracting and/or light-reflecting properties, the prism 9 allows distinctly improved visual monitoring of fluid flashback. This is because the observer receives distinctly different visual perceptions, depending on whether the observation channel section 6 is filled with air or liquid. Fluid flashback is, of course, perceptible in principle even without the prism 9. However, this is to a distinctly reduced extent. The present combination of optical prism 9 and optical lens 8 allows reliable monitoring of fluid flashback even under adverse visual conditions, for example under poor lighting conditions.

[0030] Further structural and functional features of the cannula attachment 1 will be explained below. The features explained below, notwithstanding their possible advantages, are not necessarily to be considered essential with respect to the present invention.

[0031] In the embodiment shown, the optical lens 8 and the optical prism 9 are formed by the same transparent wall 10 of the body 2. This is shown in detail by means of FIG. 8. The optical lens 8 and the optical prism 9 are thereby integrally joined. The optical lens 8 is assigned to an outer face 11 of the transparent wall 10. The optical prism 9 is assigned to an inner face 12 of the transparent wall 10. The outer face 11 faces an environment which is not further identified. The inner face 12 faces the observation channel section 6.

[0032] In the present case, the body 2 is made of a transparent plastic material T in one piece. In this respect, the body 2 is see-through not only in the transparent region 7, but also away from it. In embodiments not depicted in a drawing, a multipart design can also be provided instead of a one-piece design of the body. In addition, in further embodiments, the body is see-through only in its transparent region.

[0033] The fluid channel 5 is elongate between the proximal end 3 and the distal end 4. Starting from the proximal end 3, the fluid channel 5 initially has a proximal channel section 13, which opens into a proximal channel opening 14 in the proximal direction. In the distal direction, the proximal channel section 13 opens into the observation channel section 6. The observation channel section 6 opens into the receiving recess A in the distal direction. In the region of the dashed line drawn in for illustration in FIGS. 6 and 8, the fluid channel 5 is subdivided into, firstly, the proximal channel section 13 and, secondly, the observation channel section 6. This subdivision is to be understood as illustrative. In any case, the observation channel section 6 is formed by the section of the fluid channel 5 that extends directly below the optical lens 8 in the plan view (FIGS. 1 and 7).

[0034] The fluid channel 5 has a total volume V1, V2. In the embodiment shown, the total volume V1, V2 is composed of a first volume fraction V1 of the observation channel section 6 and a second volume fraction V2 of the proximal channel section 13. In other words, the total volume V1, V2 is the sum of the first volume fraction V1 and the second volume fraction V2 in the present case. In the embodiment shown, the first volume fraction V1 of the observation channel section 6 is dimensioned as large as possible. This is in relation to the second volume fraction V2. In preferred embodiments, the first volume fraction V1 occupies a large portion of the total volume V1, V2. As a result of the first volume fraction V1 being dimensioned as large as possible, a relatively low flow velocity of fluid flashback when entering the observation channel section 6 is achieved. This has been found to be particularly advantageous for various reasons.

[0035] Furthermore, with reference to FIG. 6, the fluid channel 5 has a maximum internal diameter D2 in the embodiment shown. In the present case, it is situated in the region of the proximal channel section 13, more precisely in the region of the channel opening 14. The observation channel section 6 has a maximum internal diameter D1. In the embodiment shown, the maximum internal diameter D1 of the observation channel section 6 corresponds approximately to the maximum internal diameter D2 in the region of the proximal channel section 13. Accordingly, the internal diameter, or hydraulic diameter, of the observation channel section 6 is dimensioned as large as possible in relation to the internal diameter, or hydraulic diameter, of the fluid channel 5. This supports a reduction of the flow velocity of fluid flashback in the region of the observation channel section 6. In the embodiment shown, the maximum internal diameter D1 of the observation channel section 6 is present in the longitudinal section plane which can be seen from FIG. 6. In a longitudinal section plane rotated by 90? according to FIG. 8, a different internal diameter arises. This is because of the at least one prism 9. With respect to said reduction in flow velocity, a narrowing in one plane is not significant. Instead, it is more critical that the observation channel section 6 has a comparatively largest possible effective hydraulic diameter.

[0036] In preferred embodiments, the maximum hydraulic diameter of the observation channel section is not more than 45%, particularly preferably not more than 10%, smaller than a maximum hydraulic diameter of the proximal channel section 13.

[0037] In the region of a proximal end 3, the body 2 is configured for detachable connection to a fluid-guiding medical component, such as a syringe, a medical tubing line or the like. For this purpose, the body 2 has a standardized fluid connector N at its proximal end 3. In the present case, the fluid connector N is an NRFit connector known to a person skilled in the art. It has connecting elements 15, 16 which are arranged angularly offset to each other in the circumferential direction of the proximal end 3. The connecting elements 15, 16 are configured for detachable interlocking connection to complementary connecting elements of a correspondingly complementary NRFit connector. The fluid connector N complies with a DIN EN ISO 80369-6 standard. The standardization comprises not only the shaping of the connecting elements 15, 16, but also the design of the proximal channel section 13, more precisely the internal diameter D2 and/or inner contour thereof. Furthermore, with reference to FIG. 6, the observation channel section 6 merges into the proximal channel section 13 dimensionally standardized in this respect in the proximal direction without a reduction in cross-section or practically without a significant reduction in cross-section. Owing to the manufacturing process, a draft of approximately 1? to 3? may be present.

[0038] In one embodiment not depicted in a drawing, the fluid connector is a Luer connector, more precisely a Luer lock connector, in accordance with DIN EN ISO 80369-7. In the embodiment with a Luer connector, a slightly larger reduction in cross-section may be present.

[0039] The optical lens 8 has different lens sections 81, 82, 83 in the region of the outer face 11 of the transparent wall 10 (FIGS. 1, 3 and 7). They can also be referred to as central section 18, medial section 82, and lateral section 83. The central section 81 has a planar outer contour, and so there is no curvature, especially in the longitudinal direction of the observation channel section 6. In the transverse direction as well, the central section 81 has no curvature in the present case. In contrast, the medial section 82 and the lateral section 83 are in any case inclined and/or curved in the transverse direction. The inclination and/or curvature is inwardly directed in the radial direction of the observation channel section 6 proceeding from the central section 81.

[0040] In the embodiment shown, the optical lens 8 is at least substantially, preferably completely, elongate over an entire length of the observation channel section 6. In further embodiments, the optical lens 8 has a different design.

[0041] The optical prism 9 is in the form of a roof prism P in the embodiment shown. The optical prism 9 has a triangular cross-sectional area and/or prism faces 91, 92 which inwardly run toward each other in the radial direction of the observation channel section 6 and which can also be referred to as first prism face 91 and second prism face 92. The prism faces 91, 92 form boundary faces of the observation channel section 6. The prism 9 has end faces 93, 94 which are arranged opposite each other in the longitudinal direction of the observation channel section 6. In the region of the end faces 93, 94, the prism 9 is flattened at an acute angle. In embodiments not depicted in a drawing, the at least one prism has a different design. For example, the prism can be in the form of a triple prism.

[0042] In the embodiment shown, the longitudinal extent of the prism 9 corresponds to the longitudinal extent of the lens 8. The prism 9 is arranged below the central section 81 of the lens 8 in the radial direction of the observation channel 6. In the transverse direction of the central section 81, the prism 9 is centrally oriented. A common edge of the prism faces 91, 92 lies centrally below the central section 81.

[0043] In the embodiment shown, the cannula attachment 1 has two optical prisms 9, 9 (FIG. 4) and two optical lenses 8, 8 (FIG. 5). They can also be referred to as first lens 8 and second lens 8 and as first prism 9 and second prism 9. In the embodiment shown, the prisms 9, 9 and the lenses 8, 8 form a first lens-prism pair 8, 9 and a second lens-prism pair 8, 9.

[0044] With respect to the design and functioning of the second lens 8 and the second prism 9, what has already been stated in relation to the first lens 8 and the first prism 9 applies mutatis mutandis. In this respect, further explanations in this connection are unnecessary.

[0045] The first lens-prism pair 8, 9 and the second lens-prism pair 8, 9 are arranged angularly offset to each other in the circumferential direction of the observation channel section 6. The angular offset is 180? in the embodiment shown, and so said pairs are diametrically opposed in relation to the observation channel section 6.

[0046] In one embodiment not depicted in a drawing, only a single lens-prism pair is present. In further embodiments, more than two lens-prism pairs are present, in particular three, four, five, six or more. Moreover, in a further embodiment, the angular offset is 90?, instead of the 180? shown here.

[0047] In the present case, the body 2 in the region of the observation channel section 6 has a cuboid shape with pairs of opposite outer faces A1, A2 (FIG. 5) and A3, A4 (FIG. 7). It will be understood that there is no exact cuboid shape, but merely a basically cuboid shape. The outer faces A1 to A4 can also be referred to as upper face A1, lower face A2, medial face A3 and lateral face A4. The first lens-prism pair 8, 9 is assigned to the upper face A1. The second lens-prism pair 8, 9 is assigned to the lower face A2. In the present case, the medial face A3 and the lateral face A4 are each provided with a ribbing 18 having multiple projections 17. The ribbings 18 facilitate gripping and manipulation of the cannula attachment 1 between the fingers of a hand.

[0048] In the embodiment shown, the body 2 has a plate 20. The plate 20 is arranged in the region of said subdivision between the observation channel section 6 and the proximal channel section 13 in the longitudinal direction of the fluid channel 5. The plate 20 outwardly projects from the fluid connector N in the radial direction. The plate 20 can serve, for example, as an axial stop for a complementary fluid connector and can accordingly also be referred to as a stop plate. Whether a stop is present also depends, of course, on the particular design of the complementary fluid connector.

[0049] Furthermore, the body 2 has a marking section 19 which marks an alignment oriented around the longitudinal axis of the body 2. In the present case, the marking section 19 is assigned to the upper face A1. Moreover, the marking section 19 is in the form of a radially inwardly recessed notch on the plate 20 that is not further identified.