Cannula attachment for spinal cannula

Abstract

1. Cannula attachment for spinal cannula 2.1 Such a cannula attachment is known, comprising a body extending between a proximal end and a distal end, a fluid channel extending through said body and having an observation channel section visible from the outside through a transparent region of said body, and comprising at least one optical lens disposed in said transparent region, through which said observation channel section is viewed by optical magnification. 2.2 According to the invention, at least one optical prism is present in said observation channel section and is configured for refraction and / or reflection of light entering said observation channel section through said optical lens. 2.3 Use of spinal cannulas

Description

[Technical field]

[0001] The present invention relates to a cannula attachment for a spinal cannula comprising a body extending between a proximal end and a distal end, a fluid channel extending through the body and having an observation channel section externally visible through a transparent region of the body, and at least one optical lens disposed in the transparent region through which the observation channel section is viewed under optical magnification. [Background technology]

[0002] A spinal cannula is used, for example, as part of spinal anesthesia to puncture the spinal cord, and comprises a cannula attachment and a hollow needle fixed to the cannula attachment. During use, the hollow needle is advanced into the cerebrospinal fluid space of the spinal cord, which is filled with cerebrospinal fluid (CSF). To confirm the correct position of the hollow needle, a flashback of fluid entering the cannula attachment is visually monitored.

[0003] A cannula attachment configured for visual monitoring is disclosed in US6656161B2, which comprises a body and a hollow needle fixable to its distal end. A fluid channel extends between the distal and proximal ends of the body. The fluid channel has an observation channel section called a chamber. The wall of the body adjacent to the chamber is provided with an optical lens, the purpose of which is to allow an observer to magnify and visually perceive the chamber from the outside. The purpose is to improve detection of fluid flashback. Furthermore, the patent teaches that the chamber should have as small a volume as possible. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide a cannula attachment of the type mentioned at the outset which allows improved visual monitoring of fluid flashback. [Means for solving the problem]

[0005] This object is achieved by the presence in the observation channel section of at least one optical prism configured for refraction and / or reflection of light entering the observation channel section through the optical lens. Thanks to the light-refracting and / or light-reflecting optical properties of the at least one prism, the observer receives a clearly different visual perception and / or image depending on whether the observation channel section is filled with air or with liquid. In principle, a visual difference would occur even in the absence of the at least one prism. However, without the prism, the visual difference would be clearly smaller and therefore more difficult for the observer to perceive. Thanks to the at least one optical prism, it can be very clearly established whether a fluid flashback has already taken place in the observation channel section or not. The inventors recognize that the combination of, firstly, optical magnification and, secondly, refraction and / or reflection of light allows a particularly reliable and simple visual monitoring even under adverse lighting conditions. The cannula attachment can also be called a cannula hub or simply a hub. The distal end of the body is configured for connection to the hollow needle of the spinal cannula. Preferably, the proximal end located on the opposite longitudinal side of the body is adapted for connection to a further medical component, e.g. a syringe, a medical tubing line, etc. Fluid flashback occurs in the proximal direction. In one embodiment, the at least one optical prism is a component that is manufactured separately from the body and then inserted into the observation channel section. In another embodiment, the at least one optical prism is integrally integrated into the body. The same applies mutatis mutandis with respect to the at least one optical lens. Thus, the at least one optical lens is manufactured in one embodiment as a separate component and then attached to the body. In another embodiment, the at least one optical lens is integrally integrated into the body. The body is transparent at least in the region of the observation channel section, the at least one optical lens and / or the at least one optical prism. For this, the body is made of a transparent material, preferably plastic, at least in the cross section.

[0006] In one embodiment, the at least one optical lens and the at least one optical prism are formed by the same transparent wall of the body and are therefore integrally joined, the at least one optical lens being assigned to an outer surface of the transparent wall and the at least one optical prism being assigned to an inner surface of the transparent wall. This results in a simple structure of the cannula attachment and simplifies its manufacture and assembly. The integral structure of the at least one optical lens and the at least one optical prism in the body, and more precisely in its transparent wall, allows a reduction in the number of necessary parts of the cannula attachment. The outer surface of the transparent wall faces radially away from the observation channel section. The inner surface of the transparent wall faces radially towards the observation channel section. The transparent wall of the body is arranged in or forms the transparent region of the body. The outer surface of the transparent wall is in contact with the environment. The inner surface of the transparent wall is in contact with the observation channel section.

[0007] In one embodiment, the fluid channel has a total volume and the observation channel section occupies the main volume fraction of the total volume. In other words, the observation channel section is as large as possible compared to other dimensions of the fluid channel and / or body. The observation channel section therefore occupies the main volume fraction of the total volume of the fluid channel. The relatively large dimensions of the observation channel section mean that a relatively low flow rate of the fluid flashback can be achieved. This is for an observation channel section with a relatively small dimension. Thanks to the slower flow rate, the observer has more time to visually recognize the fluid flashback occurring. The inventors have recognized that a lower flow rate is related to a further improvement of the visual monitoring. As a result of the quick visualization of the fluid flashback, the observer can react more quickly and therefore less fluid needs to be aspirated. Furthermore, dripping of CSF from the cannula attachment can be avoided. As a result, the fluid flashback is only detected when the fluid is dripping, and as a result, the patient's loss of fluid can also be avoided. As a result, adverse effects on the patient's health can be avoided. In particular, the risk of so-called post-dural puncture headache (PDPH) is reduced.

[0008] In one embodiment, the fluid channel has a maximum internal diameter that is at most 45%, preferably at most 10%, larger than the maximum internal diameter of the observation channel section. In other words, the observation channel section has in this embodiment an internal diameter that is as large as possible relative to the other diametric dimensions of the fluid channel. Preferably, the internal diameter of the fluid channel is variable over its longitudinal extent. Thus, the fluid channel has a channel section with a relatively narrow diameter and a channel section with a relatively wide diameter. The diameter of the observation channel section is as wide as possible. In one embodiment, the maximum internal diameter of the observation channel section is the maximum internal diameter of the entire fluid channel. Thanks to the relatively large maximum internal diameter of the observation channel section, a relatively low flow rate of fluid flashback is obtained. For related advantages, please refer to the explanations related to the previous embodiment. What is said there also applies mutatis mutandis to this embodiment of the invention. The internal diameter can also be called the hydraulically effective diameter or hydraulic diameter and in this respect can have an area dimension.

[0009] In one embodiment, the proximal end of the body has a standardized fluid connector with a standardized inner diameter, the maximum inner diameter of the observation channel section being smaller than the standardized inner diameter of the fluid connector by no more than 45%, preferably no more than 10%. This embodiment also has a relatively large inner diameter of the observation channel section, which inner diameter is defined relative to the standardized inner diameter of the standardized fluid connector. This embodiment also allows for the lowest possible flow rate of fluid flashback in the observation channel section. See above for related advantages. In one embodiment, the standardized fluid connector is an NRFit connector according to DIN EN ISO 80369-6, the maximum inner diameter of the observation channel section being smaller than the standardized inner diameter of the NRFit connector by no more than 20%, preferably no more than 15%, particularly preferably no more than 10%. In another embodiment, the fluid connector is a Luer connector according to DIN EN ISO 80369-7, the maximum inner diameter of the observation channel section being smaller than the standardized inner diameter of the Luer connector by no more than 45%, preferably no more than 30%.

[0010] In one embodiment, there are at least two optical prisms and at least two optical lenses, the pairs in the form of lens-prism pairs being arranged angularly offset from each other in the circumferential direction of the observation channel section. As a result of the angularly offset arrangement of the lens-prism pairs, visual monitoring can be performed by an observer at different viewing angles with respect to the body. In other words, the observer can monitor the fluid flashback not only in a single line of sight towards the body, but also in different line of sight directions. This further improves visual monitoring. If there are exactly two lens-prism pairs, they are preferably arranged angularly offset from each other by 90° or 180°. In the case of an angular offset of 90°, for example, monitoring can be performed looking towards the top surface as well as the right and / or left side of the body. In the case of an angular offset of 180°, monitoring can be performed from both sides of the body. If there are more than two lens-prism pairs, the angular offset is preferably the quotient of the circumferential angle 360° of the observation channel section and the number of lens-prism pairs. For example, if there are 10 lens-prism pairs, the angular offset is preferably 36°.

[0011] In one embodiment, a first lens-prism pair is arranged on a first surface of the body, preferably the upper surface, and a second lens-prism pair is arranged on a second surface of the body, preferably the opposite lower surface. Firstly, this embodiment of the invention allows visual monitoring at various viewing angles. At the same time, a relatively large effective inner diameter of the observation channel section can be maintained. The inventors have realized that, on the one hand, arranging as many angularly offset prisms as possible in the observation channel section has a positive effect on visual monitoring. On the other hand, this reduces the effective diameter of the observation channel section. This can lead to relatively high flow rates of fluid flashback, which in turn can have a negative effect on visual monitoring. The embodiment with two lens-prism pairs represents a kind of optimum in this respect.

[0012] In one embodiment, the body in the region of the observation channel section has a cubic shape with a pair of outer surfaces located opposite each other, at least one optical lens being assigned to one of the outer surfaces. The cubic shape of the body in the region of the observation channel section allows the dimensions of the observation channel section to be relatively large. Furthermore, the cubic shape aids in the handling of the cannula attachment, since the pair of outer surfaces located opposite each other can be advantageously ergonomically gripped between the fingers of the hand. Furthermore, the cubic shape allows for an easy visual monitoring of the angular orientation of the cannula attachment. To further simplify this monitoring, the body can have a marking section on one of its outer surfaces, preferably on its upper surface. This can be, for example, in the form of a recess, a protrusion, etc.

[0013] In one embodiment, the body is integrally made of a transparent plastic material. First, this simplifies manufacturing by avoiding the use of different materials for different sections of the body. Second, the fully transparent design of the body supports the incidence of light into the observation channel section, which can further improve visual monitoring of fluid flashback.

[0014] The invention further relates to a spinal cannula comprising a cannula attachment as described above and comprising a hollow needle fixed to the cannula attachment, the hollow needle being fixed to the distal end of the cannula attachment, the hollow needle having an elongated and continuous lumen between a sharpened distal end and a proximal end as known to those skilled in the art, the lumen of the hollow needle being in fluid communication with the fluid channel of the cannula attachment as known in principle.

[0015] Further advantages and features of the present invention will become apparent from the following description of preferred embodiments of the invention, which is illustrated in the claims and with reference to the drawings. [Brief description of the drawings]

[0016] [Figure 1]FIG. 2 shows a schematic top view of an embodiment of a spinal cannula according to the present invention, comprising an embodiment of a cannula attachment according to the present invention and comprising a hollow needle fixed to the cannula attachment. [Diagram 2] A schematic perspective view of a cannula attachment viewed facing the distal end is shown. [Diagram 3] A further schematic perspective view of the cannula attachment viewed facing the proximal end is shown. [Figure 4] FIG. 13 shows a schematic rear view of the cannula attachment from the distal direction. [Diagram 5] FIG. 2 shows a schematic side view of the cannula attachment. [Figure 6] Similar to FIG. 5, a schematic longitudinal section of the cannula attachment taken along section VI-VI is shown. [Figure 7] 1 shows a schematic plan view of a cannula attachment. [Figure 8] 8 shows a further longitudinal section of the cannula attachment along section VIII-VIII. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] According to FIG. 1, a spinal cannula S is intended for use in spinal anesthesia and comprises a hollow needle K and a cannula attachment 1 .

[0018] The hollow needle K is designed as known to those skilled in the art and is intended for puncturing the spinal cord. In this respect, the hollow needle K is elongated between a proximal end, not further specified, and a distal end E, the distal end E 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 as known to those skilled in the art. For example, the proximal end of the hollow needle K can be glued in the receiving recess A.

[0019] The cannula attachment 1, which may also be referred to as a cannula hub or hub, comprises a body 2 extending between a proximal end 3 and a distal end 4. Additionally, the cannula attachment 1 comprises a fluid channel 5 extending through the body 2 and having an observation channel section 6. The observation channel section 6 is externally visible through a transparent region 7 (FIG. 2) of the body 2. Additionally, the cannula attachment 1 comprises at least one optical lens 8 disposed in the transparent region 7. The optical lens 8 allows the observation channel section 6 to be externally visible with optical magnification.

[0020] When using the spinal cannula S, the spinal cord is punctured by 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. If there is a corresponding fluid flashback in the proximal direction, the correct position of the distal end E can be assumed. Said fluid flashback can be visually monitored by means of an observation channel section 6 arranged in a transparent area 7. At least one optical lens 8 supports the visual monitoring by optical magnification of the observation channel section 6.

[0021] To allow further improved visual monitoring, the cannula attachment 1 also comprises at least one optical prism 9, which is illustrated by 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 entering the observation channel section 6 through the transparent area 7 and / or the optical lens 8. Due to its light-refractive and / or light-reflective properties, the prism 9 allows a clearly improved visual monitoring of the fluid flashback. This is because the observer receives a clearly different visual perception depending on whether the observation channel section 6 is filled with air or with liquid. Naturally, the fluid flashback is in principle perceptible even without the prism 9. However, the extent will be clearly less. The present combination of the optical prism 9 and the optical lens 8 allows for reliable monitoring of the fluid flashback even under poor visual conditions, e.g. poor lighting conditions.

[0022] Further structural and functional features of the cannula attachment 1 are described below. The features described below, despite their possible advantages, are not necessarily considered essential with respect to the present invention.

[0023] 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 Fig. 8. The optical lens 8 and the optical prism 9 are thereby integrally joined. The optical lens 8 is assigned to an outer surface 11 of the transparent wall 10. The optical prism 9 is assigned to an inner surface 12 of the transparent wall 10. The outer surface 11 faces the environment, which is not further specified. The inner surface 12 faces the observation channel section 6.

[0024] In this example, the body 2 is made integrally of a transparent plastic material T. In this respect, the body 2 is see-through not only in the transparent area 7 but also away from the transparent area 7. In an embodiment not depicted in the drawings, instead of a one-piece design of the body, a multi-part design can also be provided. Additionally, in a further embodiment, the body is see-through only in its transparent area.

[0025] The fluid channel 5 is elongated between the proximal end 3 and the distal end 4. Starting from the proximal end 3, the fluid channel 5 first has a proximal channel section 13, which opens in the proximal direction into a proximal channel opening 14. In the distal direction, the proximal channel section 13 opens into an observation channel section 6, which opens in the distal direction into a receiving recess A. In the area of ​​the dashed lines drawn for illustration in Figs. 6 and 8, the fluid channel 5 is subdivided firstly into a proximal channel section 13 and secondly into an observation channel section 6. This subdivision should be understood as exemplary. In each case, the observation channel section 6 is formed by a section of the fluid channel 5, which in plan view (Figs. 1 and 7) extends directly below the optical lens 8.

[0026] The fluid channel 5 has a total volume V1, V2. In the illustrated embodiment, 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 this example. In the illustrated embodiment, the first volume fraction V1 of the observation channel section 6 is dimensioned as large as possible. This is relative to the second volume fraction V2. In a preferred embodiment, the first volume fraction V1 occupies the majority 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 rate of the fluid flashback when entering the observation channel section 6 is obtained. This has been found to be particularly advantageous for various reasons.

[0027] Further, with reference to FIG. 6, the fluid channel 5 has a maximum internal diameter D2 in the illustrated embodiment. In this example, this is located 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 illustrated embodiment, 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. The internal diameter, i.e. the hydraulic diameter, of the observation channel section 6 is therefore dimensioned as large as possible relative to the internal diameter, i.e. the hydraulic diameter, of the fluid channel 5. This supports a reduction in the flow rate of the fluid flashback in the region of the observation channel section 6. In the illustrated embodiment, the maximum internal diameter D1 of the observation channel section 6 lies in the longitudinal section plane seen from FIG. 6. In the longitudinal section plane rotated by 90° according to FIG. 8, a different internal diameter results. This is due to at least one prism 9. With regard to the reduction in the flow rate, a narrowing in one plane is not important. Rather, it is more important that the observation channel section 6 has a relatively large effective hydraulic diameter as much as possible.

[0028] In a preferred embodiment, the maximum hydraulic diameter of the observation channel section is no more than 45% smaller than the maximum hydraulic diameter of the proximal channel section 13, particularly preferably no more than 10% smaller.

[0029] In the region of the proximal end 3, the body 2 is configured for a detachable connection to a fluid-guiding medical component, such as a syringe, a medical tubing line, etc. For this purpose, the body 2 has a standardized fluid connector N at its proximal end 3. In this example, the fluid connector N is an NRFit connector, known to those skilled in the art. The fluid connector N has connection elements 15, 16 arranged angularly offset from one another in the circumferential direction of the proximal end 3. The connection elements 15, 16 are configured for a detachable interlocking connection to complementary connection elements of a corresponding complementary NRFit connector. The fluid connector N complies with the DIN EN ISO 80369-6 standard. This standardization includes not only the shaping of the connection elements 15, 16, but also the design of the proximal channel section 13, more precisely its inner diameter D2 and / or its inner contour. Furthermore, with reference to FIG. 6, the observation channel section 6 merges into the proximal channel section 13, which is standardized in dimensions at this point in the proximal direction, without a reduction in cross section or without a substantial reduction in cross section. Due to the manufacturing process, there may be a gap of approximately 1° to 3°.

[0030] In one embodiment not depicted in the drawings, the fluid connector is a luer connector, more precisely a luer lock connector according to DIN EN ISO 80369-7. In embodiments using a luer connector, there may be a slightly further reduced cross section.

[0031] The optical lens 8 has different lens sections 81, 82, 83 in the region of the outer surface 11 of the transparent wall 10 (Figures 1, 3 and 7). These can also be called central section 18, inner section 82 and outer section 83. The central section 81 has a planar outer contour and therefore has no curvature, in particular in the longitudinal direction of the observation channel section 6. In the transverse direction, the central section 81 also has no curvature in this example. In contrast, the inner section 82 and the outer section 83 are inclined and / or curved in each case in the transverse direction. The inclination and / or curvature proceeds from the central section 81 and is directed inwards in the radial direction of the observation channel section 6.

[0032] In the embodiment shown, the optical lens 8 is elongated at least substantially, and preferably completely, over the entire length of the observation channel section 6. In further embodiments, the optical lens 8 has a different design.

[0033] 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 face inwards towards each other in the radial direction of the observation channel section 6 and can also be called a first prism face 91 and a second prism face 92. The prism faces 91, 92 form the boundary surfaces 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 an embodiment not depicted in the drawings, at least one of the prisms has a different design. For example, the prism can be in the form of a triple prism.

[0034] In the illustrated embodiment, the longitudinal extent of the prism 9 corresponds to the longitudinal extent of the lens 8. In the radial direction of the observation channel 6, the prism 9 is arranged below the central section 81 of the lens 8. In the transverse direction of the central section 81, the prism 9 is centrally oriented. The common edge of the prism faces 91, 92 is centrally located below the central section 81.

[0035] In the illustrated embodiment, the cannula attachment 1 has two optical prisms 9, 9' (FIG. 4) and two optical lenses 8, 8' (FIG. 5), which may also be referred to as a first lens 8 and a second lens 8', and a first prism 9 and a second prism 9'. In the illustrated embodiment, 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'.

[0036] With regard to the design and function of the second lens 8' and the second prism 9', what has already been said with regard to the first lens 8 and the first prism 9 applies mutatis mutandis. In this respect, no further explanation in this regard is necessary.

[0037] The first lens-prism pair 8, 9 and the second lens-prism pair 8', 9' are arranged angularly offset from one another in the circumferential direction of the observation channel section 6. The angular offset is 180° in the illustrated embodiment, so that said pairs are diametrically opposed with respect to the observation channel section 6.

[0038] In one embodiment not depicted in the drawings, there is only a single lens-prism pair. In a further embodiment, there are three or more lens-prism pairs, particularly three, four, five, six or more. Furthermore, in a further embodiment, the angular offset is 90° instead of the 180° shown here.

[0039] In this example, the body 2 in the region of the observation channel section 6 has a cubic shape with pairs of outer faces A1, A2 (FIG. 5) and A3, A4 (FIG. 7) located opposite each other. It will be understood that there is no exact cubic shape, just a basically cubic shape. The outer faces A1-A4 can also be called upper face A1, lower face A2, inner face A3 and outer face A4. A first lens-prism pair 8, 9 is assigned to the upper face A1. A second lens-prism pair 8', 9' is assigned to the lower face A2. In this example, the inner face A3 and the outer face A4 are each provided with a rib 18 having a number of projections 17. The rib 18 facilitates gripping and manipulation of the cannula attachment 1 between the fingers of the hand.

[0040] In the embodiment shown, the body 2 comprises a plate 20, which is arranged in the longitudinal direction of the fluid channel 5 in said subdivided area between the observation channel section 6 and the proximal channel section 13. The plate 20 projects outward from the fluid connector N in the radial direction. The plate 20 can for example function as an axial stopper of the complementary fluid connector and can also be called a stop plate accordingly. The presence or absence of a stopper naturally depends on the concrete design of the complementary fluid connector.

[0041] Furthermore, the body 2 has a marking section 19 for marking an alignment oriented around the longitudinal axis of the body 2. In this example, the marking section 19 is assigned to the upper face A1. Furthermore, the marking section 19 is in the form of a radially inwardly recessed notch in the plate 20, not specified further.

Claims

Claim 1 A cannula attachment (1) for a spinal cannula (S), comprising a body (2) extending between a proximal end (3) and a distal end (4), and a fluid channel (5) extending through the body (2) and having an observation channel section (6) visible from the outside through a transparent region (7) of the body (2). The transparent region (7) is provided with at least one optical lens (8) through which the observation channel section (6) is visible by optical magnification. The cannula attachment (1) has at least one optical prism (9) present in the observation channel section (6) and configured for refraction and / or reflection of light incident on the observation channel section (6) through the optical lens (8). Claim 2 The at least one optical lens (8) and the at least one optical prism (9) are formed by the same transparent wall (10) of the body (2) and are thus integrally joined. The at least one optical lens (8) is assigned to an outer surface (11) of the transparent wall (10), and the at least one optical prism (9) is assigned to an inner surface (12) of the transparent wall (10). The cannula attachment (1) according to claim 1. Claim 3 The fluid channel (5) has a total volume (V1, V2), and the observation channel section (6) occupies a major volume fraction (V1) of the total volume (V1, V2). The cannula attachment (1) according to claim 1. Claim 4 The fluid channel (5) has a maximum inner diameter (D2) that is 45% or less, preferably 10% or less, larger than the maximum inner diameter (D1) of the observation channel section (6). The cannula attachment (1) according to claim 1. Claim 5 The proximal end (3) of the body (2) has a standardized fluid connector (N) with a standardized inner diameter (D2), and the maximum inner diameter (D1) of the observation channel section (6) is 45% or less, preferably 10% or less, smaller than the standardized inner diameter (D2) of the fluid connector (N). The cannula attachment (1) according to claim 1. Claim 6 There are at least two optical prisms (9, 9') and at least two optical lenses (8, 8'), and the pairs in the form of this lens - prism pair (8, 9; 8', 9') are arranged with an angular offset from each other in the circumferential direction of the observation channel section (6). The cannula attachment (1) according to claim 1.

7. The first lens - prism pair (8, 9) is arranged on the first surface (A1), preferably the upper surface, of the main body (2), and the second lens - prism pair (8', 9') is arranged on the second surface (A2), preferably the lower surface on the opposite side, of the main body (2). The cannula attachment (1) according to claim 6.

8. The main body in the region of the observation channel section (6) has a cubic shape (G) having a pair of outer surfaces (A1, A2, A3, A4) located on opposite sides of each other, and the at least one optical lens (8) is assigned to one of the outer surfaces (A1, A2, A3, A4). The cannula attachment (1) according to claim 1.

9. The main body (2) is integrally made of a transparent plastic material (T). The cannula attachment (1) according to claim 1.

10. A spinal cannula (S) comprising the cannula attachment (1) according to any one of claims 1 to 9 and a hollow needle (K) fixed to the cannula attachment (1).

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