A glass cutting cannula

Abstract

A vitrectomy cannula belongs to the field of medical instruments. The vitrectomy cannula comprises: a tube body having an insertion section and an exposed section. The tube body is hollow and the tube cavity is configured to allow the surgical instrument and the adsorbent to pass through together; a magnetic body is attached and fixed to the exposed section and / or a clamping body; the magnetic body is configured to provide resistance to the surgical instrument passing through the tube cavity of the tube body through magnetic adsorption with the adsorbent; and a soft clamping body is convexly coated on the outer surface of the exposed section. The vitrectomy cannula can be used to improve the accuracy of the operation in ophthalmic surgery.

Description

Technical Field

[0001] The present application relates to the field of medical devices, and in particular, to a vitrectomy cannula. Background Art

[0002] The vitreous body is a mass of transparent gelatinous substance that fills the back of the eye. In some ophthalmic surgeries, the vitreous body needs to be cut. During the vitrectomy operation, many surgical and auxiliary instruments need to be inserted (such as vitreous cutting head probe, optical fiber, intraocular laser, flute needle, vitreous scissors, retinal forceps, epiretinal membrane peeler, etc.).

[0003] When the refractive medium of the eyeball (cornea, aqueous humor, lens and vitreous body) is opaque or / and when operating next to a trocar in the vitreous body, surgical and auxiliary instruments are prone to fall out of the vitreous body. The fall out of surgical instruments increases the unnecessary reinsertion of instruments. When instruments are operated in the posterior segment of the vitreous body, the tip of the instrument is accidentally inserted, which may cause problems such as touching the retina, the macula itself, or retinal detachment due to excessive traction on the retina.

[0004] This will lead to time-consuming and laborious surgery, and will not be conducive to the normal progress of the surgery. Unfortunately, no exact and effective solution has been found so far. Summary of the invention

[0005] In order to improve or even solve at least one of the above problems, the present application proposes a vitrectomy cannula.

[0006] This application is implemented as follows:

[0007] In a first aspect, an example of the present application provides a vitrectomy cannula, which can be used in conjunction with a surgical instrument to perform an ophthalmic surgery.

[0008] The surgical instrument is provided with at least two adsorption parts, and the at least two adsorption parts are arranged far away from each other. The vitrectomy sleeve comprises a tube body, a magnetic body and a clamping body.

[0009] The tube body has an insertion section and an exposed section. The tube body is hollow and its lumen is configured to allow surgical instruments and an adsorbent to pass through together. A soft clamping body is wrapped around the outer surface of the exposed section in a protruding form. A magnetic body is attached and fixed to the exposed section and / or the clamping body, and the magnetic body is configured to provide resistance to the passage of the surgical instrument in the lumen of the tube body through magnetic adsorption with the adsorbent.

[0010] The vitrectomy cannula in the example has a magnetic body, so that it can provide a magnetic force between it and a specific object. When the surgical instrument is close to the vitrectomy cannula or moves in the vitrectomy cannula, the adsorption part provided on the surgical instrument can have an adsorption effect with the magnetic body of the vitrectomy cannula, so that the movement of the surgical instrument is limited and the control is more convenient, so that more accurate surgical operations can be achieved and operational deviations can be avoided.

[0011] In combination with the first aspect, in a first possible implementation manner of the first aspect of the present application, the magnetic body is in the shape of an elongated strip or a flat strip, and is arranged in a manner that two magnetic poles are distributed radially along the lumen.

[0012] In combination with the first aspect or the first embodiment of the first aspect, in a second possible implementation of the first aspect of the present application, a coating is provided on the surface of the magnetic body.

[0013] The coating covers the magnetic body and avoids direct contact between the magnetic body and the human body. By selecting the coating material, the adverse stimulation of the magnetic body to the human body can be avoided in some cases, and the excessive magnetic field strength can be suppressed to a certain extent.

[0014] In combination with the first aspect, in a third possible implementation manner of the first aspect of the present application, the clamping body has a groove sunken from the surface toward the tube body.

[0015] The groove can increase the roughness of the surface of the clamping body, thereby facilitating improving the stability of the clamping body in cooperation with other operating instruments.

[0016] In combination with the third implementation of the first aspect, in a fourth possible implementation of the first aspect of the present application, the groove is annular.

[0017] The annular groove can provide relatively more contact surfaces for operation, thereby reducing the difficulty of operation.

[0018] In combination with the first aspect, in a fifth possible implementation manner of the first aspect of the present application, the exposed section is made of metal.

[0019] The exposed section of the metal material has appropriate strength and environmental tolerance, which is beneficial to improving the service life of the vitrectomy sleeve.

[0020] In combination with the first aspect, in a sixth possible implementation manner of the first aspect of the present application, the inner diameter of the tube body is 0.6 mm to 0.8 mm.

[0021] In combination with the first aspect or the first or sixth embodiment of the first aspect, in a seventh possible implementation of the first aspect of the present application, the length of the exposed segment is 1.5 mm and the length of the inserted segment is 4 mm.

[0022] In combination with the first aspect, in an eighth possible implementation manner of the first aspect of the present application, the surgical instrument is provided with two adsorption parts, and the distance between the two adsorption parts is 16 mm to 21 mm.

[0023] The number of adsorbents in surgical instruments is not limited to two, and multiple adsorbents (such as three, four, five, or even more) may be designed. When the refractive matrix of the eyeball (composed of the cornea, aqueous humor, lens, and vitreous body) is opaque, setting multiple separated adsorbents can better control the degree of entry of some surgical instruments (such as optical fibers). In addition, it is also helpful for beginners to manage their hand posture when practicing surgery with surgical instruments.

[0024] In combination with the first aspect, in a ninth possible embodiment of the first aspect of the present application, the surgical instrument includes any one or more of a vitrectomy head probe, a light guide fiber, an intraocular laser, a flute needle, vitrectomy scissors, retinal forceps, and an epiretinal membrane peeler. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 The schematic diagram of the operation of using a flute-shaped needle to aspirate preretinal blood in existing ophthalmic surgery is shown;

[0027] Figure 2 The schematic diagram of the operation of vitrectomy in the existing eye surgery is shown;

[0028] Figure 3 This is a schematic diagram of the initial insertion of a vitrectomy head during a vitrectomy operation using the vitrectomy cannula of the present application example;

[0029] Figure 4 This is a schematic diagram of the operation of fully inserting the cutting head during vitrectomy surgery using the vitrectomy cannula of the present application example;

[0030] Figure 5 This is a schematic cross-sectional view of a vitrectomy cannula in an example of the present application;

[0031] Figure 6 It is a schematic cross-sectional structure diagram of another vitrectomy cannula in the example of this application;

[0032] Figure 7 for Figure 6Schematic diagram of the front view structure of the end face of the middle glass cutting sleeve.

[0033] Icons: 100-eyeball; 101-flute-shaped needle; 102-trocar; 103-optical fiber; 104-perfusion catheter; 105-vitrectomy head; 200-vitrectomy cannula; 201-vitrectomy head; 203-middle end; 204-head end; 205-adsorbent; 300-lumen; 301-insertion section; 302-exposed section; 303-magnetic body; 303a-magnetic strip; 304-clamping body; 305-clamping body groove; 306-tube body. DETAILED DESCRIPTION

[0034] Vitrectomy is a minimally invasive surgery that does not require a large incision on the eyeball. Instead, a trocar is used to puncture the white of the eyeball. The trocar can be used to establish the channel required for the operation, which can be a through hole with a diameter of 0.5 mm. Depending on the needs of the operation, multiple channels can be established using different numbers of trocars. These channels allow surgical instruments to enter the vitreous cavity for surgery. When the trocar is removed, the eyeball can close itself without the need for suturing, so the trauma is minimal.

[0035] For example, Figure 1 The schematic diagram of the operation of using a flute-shaped needle 101 to suck out preretinal blood in current eye surgery is shown. As shown in the figure, the eyeball 100 is punctured with a light guide fiber 103, a flute-shaped needle 101, and a trocar 102. The trocar 102 provides a channel for the flute-shaped needle 101 to enter the vitreous body through the trocar 102 and suck out preretinal blood through the tip.

[0036] For example, Figure 2 The schematic diagram of the operation of vitrectomy in current eye surgery is shown, and the trocar 102 is not drawn in the figure. As shown in the figure, the eyeball 100 is punctured with an optical fiber 103, an irrigation catheter 104 and a vitrectomy head 105. Among them, the vitrectomy head 105 enters the vitreous body and performs a cutting operation on the vitreous body through the head end. The vitrectomy machine is an instrument the size of a refrigerator, and its functions include cutting, suction, irrigation and lighting. The vitrectomy machine is connected to many channels, including multiple pipelines such as the pipeline where the vitrectomy head is located, the optical fiber, and the gas-liquid exchange tube.

[0037] In order to avoid damage and irritation to the organs and tissues of the eyeball, these operations require high precision. However, in eye surgery, due to the special physiological structure, in some cases, the difficulty of the operation will be increased. For example, the refractive medium is opaque (such as corneal scar or edema, lens opacity, intraocular lens deviation, etc.), the pupil is irregular or cannot be fully dilated, and the operation is performed next to the vitrectomy cannula. In such cases, the instrument inserted into the vitreous body is easy to fall out. Especially for surgeons who have presbyopia (usually surgeons over 40 years old) or / and the lighting in the operating room is poor (the lighting in the operating room is often turned off to see the fundus clearly during vitreous surgery), etc., it will significantly increase the unnecessary operation of reinserting the instrument.

[0038] The inventors have found through research in practice that one of the main reasons for the above problems is that the surgical instrument has a small operating space and high precision requirements, which makes it very difficult to match the trocar with the surgical instrument holder, resulting in the inability to accurately operate the surgical instrument. Specifically, the surgical instrument can move with a high degree of freedom relative to the trocar, that is, the surgical instrument is too flexible and difficult to master.

[0039] Therefore, the inventor believes that the key to solving the above technical problems lies in improving the motion coupling between the surgical instrument and the trocar. As far as the inventor knows, there is currently no effective means to solve the problem of mutual coordination between the surgical instrument and the trocar.

[0040] In view of this, after research, the inventor proposed a feasible solution - by reducing the flexibility of the surgical instrument relative to the trocar, so as to improve the operator's mastery of the surgical instrument. In the example, the relative force between the surgical instrument and the trocar is enhanced to play the role of "restraining" the surgical instrument. Specifically, in the example, the surgical instrument and the trocar are "linked" to a certain extent in the form of magnetic adsorption. Since the trocar is relatively stably and statically attached to the wall of the eyeball in actual surgery, when the two are linked, the movement of the surgical instrument can be constrained by the trocar in a relatively stable posture, thereby reducing its flexibility and freedom, reminding the operator to operate the surgical instrument in a more cautious manner, and reducing the risk of accidentally touching the surrounding tissue and accidentally detaching from the trocar, ultimately making the surgical instrument easier to control and operate.

[0041] Therefore, in the present application, the inventor proposes an improved trocar (hereinafter described as a vitrectomy trocar), which is used in conjunction with a surgical instrument. As a solution adapted to the improved trocar, the surgical instrument is also adjusted accordingly.

[0042] The surgical instruments include but are not limited to any one or more of a vitrectomy probe, an optical fiber 103, an intraocular laser, a flute needle, vitrectomy scissors, retinal forceps and an epiretinal membrane peeler.

[0043] As an adaptive adjustment, the surgical instrument is provided with at least two suction pieces, and the at least two suction pieces are arranged far away from each other.

[0044] For example, the surgical instrument can be provided with two adsorption parts, and the two adsorption parts are respectively located at the head and the middle part of the surgical instrument. Among them, the head of the surgical instrument is its main function and operation part; when the surgical instrument reaches the expected surgical position (that is, the head reaches the position such as cutting the posterior segment of the vitreous (the posterior segment of the vitreous of many patients is closely connected to the retina, which often requires more energy from the surgeon)), the middle part of the surgical instrument is the part that contacts and cooperates with the vitrectomy cannula in position. Therefore, the distance between the two adsorption parts is roughly equivalent to the axial length of a normal person's eye. For example, the surgical instrument is provided with two adsorption parts, and the distance between the two adsorption parts is 16mm to 21mm, while the length of the eye axis is usually 23mm. Exemplarily, the head end (front 4mm) and the middle and rear end (20mm~25mm, the axial length of a normal person's eye) of the surgical and auxiliary instruments (such as flute needles) are magnetizable materials (such as tungsten carbon steel), so the distance between the two adsorption parts should be 16~21mm.

[0045] For the example in which the surgical instrument may be provided with more than two adsorption members, the surgical instrument includes, in addition to the adsorption members at the above-mentioned two positions, one or two or more adsorption members located between the two positions.

[0046] For example, as an example of providing two adsorption members, the surgical instrument can be selected as a vitrectomy head 201, such as Figure 3 and Figure 4 As shown. The eyeball 100 establishes an operation channel through the vitrectomy cannula 200, and the vitrectomy head 201 is inserted into the vitreous body through the vitrectomy cannula 200. An adsorbent 205 is provided at the head end 204 (head) of the vitrectomy head 201, and an adsorbent 205 is provided at the middle end 203 (middle) of the vitrectomy head 201. In the example, the vitrectomy head 201 is used as an example for explanation, but for other types of surgical instruments or auxiliary instruments (such as optical fibers or so-called light guides, flute needles, etc.), the content expressed in this example has the same applicability.

[0047] It should be noted that the adsorbent provided on the surgical instrument / auxiliary instrument is an object that can generate magnetic force with a magnet, which can be a magnet or other object that can be magnetically adsorbed by a magnet, such as iron sheet, iron coating or magnet coating or tungsten carbon steel film, etc. It is understandable that the part or area of ​​the surgical instrument that does not need to generate magnetic adsorption (such as the part between the head end and the middle end) can be made of materials required in ophthalmic surgery such as plastic, glass, titanium alloy, etc. The adsorbent can be fixed on the surgical instrument in various ways, such as precision welding (micro-beam plasma arc welding, laser welding).

[0048] Therefore, the two adsorbing members 205 disposed on the vitreous cutting head 201 serve as its magnetizable region, and can be magnetically adsorbed thereto when approaching a magnet or a magnetic material (ie, a magnetic object).

[0049] In the present application example, the magnetic object is provided by a vitrectomy sleeve 200. The vitrectomy sleeve 200 in the example will be described in detail below. Figure 5 , Figure 6 and Figure 7 shown.

[0050] The vitrectomy cannula 200 includes a tube body 306, a clamping body 304, and a magnetic body 303. The tube body 306 constitutes the main part of the vitrectomy cannula 200, and the clamping body 304 and the magnetic body 303 are both attached to the tube body 306 and fixed. The tube body 306 of the vitrectomy cannula 200 can provide a channel for various surgical instruments / auxiliary instruments to move (insert into the eyeball). The clamping body 304 is used to operate (such as clamp) the vitrectomy cannula 200; the magnetic body 303 is used to provide constraints to the surgical instruments, so that the movement of the surgical instruments is more controllable.

[0051] The tube body 306 is generally in a columnar structure, and thus can be a cylinder or an elliptical cylinder, etc. The tube body 306 is also hollow, and thus, the tube body 306 has a lumen 300 , and the lumen 300 can be used as a passage to allow surgical instruments and suction components to pass through together to enter and exit the eyeball.

[0052] In terms of usage and function, the tube body 306 can be roughly divided into two parts, namely, the insertion section 301 and the exposed section 302. The insertion section 301 is a structure inserted into the eyeball (such as the eyeball wall, eyeball conjunctiva and sclera); the exposed section 302 is a structure exposed outside the eyeball. The tube body 306 can be made of one material and processed by an integrated molding method, such as Figure 5 Alternatively, the insertion section 301 and the exposed section 302 of the tube body 306 are made of different materials, such as Figure 6As shown. The example of the tube body 306 made of different materials is that the insertion section 301 is titanium alloy and the exposed section 302 is medical stainless steel, and the two can be fixed by welding. As an alternative, the exposed section 302 is made of metal.

[0053] The length of the tube body 306 can be designed according to the needs of the operation and does not need to be specifically limited. Generally, its length can be 5mm, 6mm, etc., so as to at least be able to pass through the wall of the eyeball and be stably fixed to the wall of the eyeball. The lengths of the insertion section 301 and the exposed section 302 can be selectively adjusted according to the design requirements, but usually, the length of the insertion section 301 is greater than the length of the exposed section 302. For example, the length (D1) of the exposed section 302 is 1.5mm and the length (D2) of the insertion section 301 is 4mm. The size of the lumen 300 of the tube body 306 is defined by the inner diameter, and illustratively, the inner diameter of the tube body 306 is 0.6mm to 0.8mm. For example, when the inner diameter of the tube body 306 is 0.6 mm, the size of the instrument that can be inserted is 27G (Gauge); when the inner diameter of the tube body 306 is 0.7 mm, the size of the instrument that can be inserted is 25G; when the inner diameter of the tube body 306 is 0.8 mm, the size of the instrument that can be inserted is 23G.

[0054] The clamping body 304 is made of a soft material, such as an elastic resin, silicone, etc. Therefore, the clamping body 304 can be stably clamped and fixed and is not easily damaged. At the same time, based on the consideration of convenient operation, the clamping body 304 is coated on the outer surface of the exposed section 302 in a protruding form. In other words, the tube body 306 presents a large diameter area (enlarged part) in the exposed section 302 by setting the clamping body 304. Furthermore, the clamping body 304 can also be selected to have an appropriate color to improve recognizability. The color can be achieved by adding pigments to the clamping body 304 or fixing coloring strips.

[0055] The clamping body 304 can be fixed to the exposed section 302 of the tube 306 by bonding with medical glue. Alternatively, the clamping body 304 is selected as a tubular sleeve made of elastic silicone material, and its inner diameter is smaller than the outer diameter of the exposed section 302 of the tube 306, so that the tubular sleeve can be fixed to the tube 306 in a sleeve-joined manner. In addition, the clamping body 304 can also be provided with a clamping body groove 305, which is recessed from the surface of the clamping body 304 to the tube 306. The clamping body groove 305 can improve the operability of the clamping body 304. Structurally, the clamping body groove 305 can be annular, such as a circular ring, an elliptical ring, or a rectangular ring, etc.; or, the clamping body groove 305 is a ring segment. The shape of the clamping body groove 305 can be defined by its cross-sectional shape, for example, its cross-section is trapezoidal, rectangular, or arc-shaped, etc. Further, the distribution of the clamping body groove 305 can also be adjusted. For example, the annular clamping body groove 305 is parallel to the cross section of the tube body 306 or substantially coaxial with the tube body 306 .

[0056] Therefore, in ophthalmic surgery, when the vitrectomy cannula 200 is used to construct a movable channel for surgical instruments, the insertion section 301 can be inserted into the eyeball, while the clamping body 304 can be exposed outside the eyeball and can limit the tube body 306 from further extending into the eyeball.

[0057] The magnetic body 303 is provided as a component that provides magnetic force to constrain the movement of the surgical instrument to a certain extent. The magnetic body 303 is configured to provide resistance to the passage of the surgical instrument in the lumen 300 of the tubular body 306 through magnetic adsorption with the adsorbent 205. The magnetic body 303 can be attached and fixed to the exposed section 302 or the clamping body 304, or can be provided on the exposed section 302 and the clamping body 304 at the same time. Since the magnetic force can interact with other objects indirectly, the magnetic body 303 does not necessarily have to be in contact with or directly opposite to the surgical instrument. The number of the magnetic body 303 can be one or more, which can be selected according to the design requirements without special restrictions.

[0058] Based on this, and considering the fixation of the magnetic body 303, the magnetic body 303 can be directly embedded in the clamping body 304, for example, snapped into the clamping body groove 305 of the clamping body 304, for example, arranged in a groove of a side wall of the vitrectomy sleeve. Alternatively, the magnetic body 303 is attached to the surface of the exposed section 302 as a coating layer, such as Figure 5 Alternatively, the magnetic body 303 is inserted from the clamping body 304 along the radial direction of the tube body 306 until it contacts the exposed tube of the tube body 306. For example, the magnetic body can also be configured in the form of a long strip or a flat strip or a sphere or an ellipsoid to form a magnetic strip 303a, and is arranged in a manner that two magnetic poles are distributed radially along the tube cavity 300, such as Figure 6 and Figure 7In some examples, the magnetic strip 303a may also have one magnetic pole facing the lumen and the other magnetic pole facing outside the lumen, that is, the magnetic strip 303a is arranged along the radial direction of the lumen.

[0059] As an optional solution, a coating is provided on the surface of the magnetic body 303. The coating can cover and shield the magnetic body 303, thereby preventing the eyeball from being affected by the highly active magnetic body 303 (such as a neodymium iron boron magnet).

[0060] The magnetic body 303 can be selected according to the size of the tube body 306, the size and material of the clamping body 304, etc. Usually, its magnetic force is appropriately limited to avoid being too large or too small. In general, the magnetic body 303 can generate a slight attraction, and its attraction can both attract the attention of the surgeon and not affect normal operation due to excessive attraction. During normal surgical operation, when the magnetizable part of the surgical instrument is located in the channel, it attracts the vertical bar magnet. However, because the metal tube body 306 channel area is between the two, the magnetic field passes through so that the strength is effectively limited (weakened).

[0061] In some cases, during ophthalmic surgery, when the surgical instrument reaches the vitrectomy cannula 200, the head end of the surgical instrument and the vitrectomy cannula 200 are attracted to each other through magnetic force, thereby increasing the movement resistance of the surgical instrument (which can also serve as a guide and positioning function), reminding the surgeon to operate with caution and reducing the risk of accidental dislodgment of the instrument.

[0062] In ophthalmic surgery, when the tip of the surgical instrument is working near the retina at the back of the eye (such as a vitrectomy head or a flute needle sucking out blood in front of the retina at the back of the eye, such as an intraocular laser performing laser treatment on the diseased vascular area of ​​the retina, such as an epiretinal membrane peeler removing the epiretinal proliferative membrane, etc.), the middle end of the surgical instrument is approximately located in the vitrectomy cannula 200 (at this time the two are attracted to each other by magnetic force), thereby increasing the movement resistance of the surgical instrument (it can also play a guiding and positioning role), reminding the surgeon to operate carefully, and reducing the risk of accidentally touching the retina or the macula itself.

[0063] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the above content is combined with the drawings in the embodiments of the present application to clearly and completely describe the technical scheme in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present application.

[0064] It should be noted that like reference numerals and letters denote similar items in the drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0065] In the description of the present application, it should be noted that the terms "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is usually placed when in use. These are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0066] In the description of this application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0067] In this application, all embodiments, implementation methods and features of this application can be combined with each other without contradiction or conflict. In this application, conventional equipment, devices, components, etc. can be purchased commercially or made according to the contents disclosed in this application. In this application, in order to highlight the key points of this application, some conventional operations and equipment, devices, and components are omitted or simply described.

[0068] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A vitrectomy cannula, used in conjunction with a surgical instrument, characterized in that: The surgical instrument is provided with at least two adsorption members, and the at least two adsorption members are arranged far away from each other, and the two adsorption members are respectively located at the head and the middle of the surgical instrument; the distance between the two adsorption members is 16 mm to 21 mm; the vitrectomy cannula includes: A tube body, having an insertion section and an exposed section, wherein the tube body is hollow and the lumen is configured to allow the surgical instrument and the adsorbent to pass through together; the tube body is made of metal; A soft clamping body is covered on the outer surface of the exposed section in a protruding form; A magnetic body is attached and fixed to the exposed section and / or the clamping body, and the magnetic body is configured to provide resistance to the passage of the surgical instrument in the lumen of the tube body through magnetic adsorption with the adsorbent; the resistance both reminds the operator to operate the surgical instrument with caution and allows the surgical instrument to move in the lumen, thereby not affecting the operator's operation of the surgical instrument.

2. The vitrectomy cannula according to claim 1, characterized in that: The magnetic body is in the shape of a long strip or a flat strip, and is arranged in a manner that two magnetic poles are distributed radially along the lumen.

3. The vitrectomy cannula according to claim 1 or 2, characterized in that: A coating is provided on the surface of the magnetic body.

4. The vitrectomy cannula according to claim 1, characterized in that: The clamping body has a groove recessed from the surface toward the tube body.

5. The vitrectomy cannula according to claim 4, characterized in that: The groove is annular.

6. The vitrectomy cannula according to claim 1, characterized in that: The inner diameter of the tube body is 0.6 mm to 0.8 mm.

7. The vitrectomy cannula according to claim 1 or 6, characterized in that: The length of the exposed section is 1.5 mm, and the length of the inserted section is 4 mm.

8. The vitrectomy cannula according to claim 1, characterized in that: The surgical instrument comprises any one or more of a vitrectomy probe, an optical fiber, an intraocular laser, a flute needle, vitrectomy scissors, retinal forceps and an epiretinal membrane peeler.

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