Device for use in surgery

Abstract

There is provided a constriction device (100) for use in surgery to surround a physiological structure, comprising: a strip (101) having a main body (102), a first end (110) and a second end (120) opposite the first end; wherein the first end has a passageway (112) therethrough configured to receive the second end and engage the main body and thereby form a fixed loop. The passageway is provided at an angle to the main body such that, in use, the second end extends therefrom, toward the main body and lies substantially flat against the loop, along the length of the main body. The strip may comprise a visual indicator to visually determine the size of the fixed loop.

Description

[0001] DEVICE FOR USE IN SURGERY

[0002] FIELD

[0003] The invention relates to devices for use in surgery. Specifically, the invention relates to constriction devices for use in surgery to surround a physiological structure. The invention also relates to a method of using the device.

[0004] BACKGROUND

[0005] In various types of surgery, it may be necessary to control blood flow to and from organs in order to safely conduct the operation. This is often done by clamping or constricting a part of the organ, a nearby ligament or a proximate physiological structure, to facilitate haemostasis or control of blood flow.

[0006] A type of surgery in which constriction of a physiological structure is required is liver surgery. During surgery on the liver, the hepatoduodenal ligament may be clamped to limit blood inflow through the hepatic artery and the portal vein in order to control bleeding from the liver. This is known in the field as the Pringle Manoeuvre. The hepatoduodenal ligament is a physiological structure and, when clamped during surgery, blood inflow into the liver can be controlled, with no effect on the outflow. It is necessary to use the Pringle Manoeuvre for defined periods of time during surgical operations to effectively reduce intraoperative blood loss. Similar procedures may be implemented in other types of surgery, for example abdominal and cardiac operations, where there is a requirement of surrounding a physiological structure to control blood flow.

[0007] Managing bleeding and maintaining a bloodless surgical field is particularly important during minimally invasive robotic and laparoscopic operations. Surgeons depend heavily on visual cues, and blood can absorb the camera light, resulting in a darker operative field. This can hinder the ability to perform the procedure effectively and may even necessitate conversion to open surgery.

[0008] Existing methods for controlling blood flow in such surgeries include using a haemostat clamp (which may not be suitable for minimally invasive laparoscopic surgery or provide sufficient and reliable clamping of some physiological structures), tape, cord, or even clamping the physiological structure using hands or adapted catheters. None of these solutions are ideal and specifically designed for purpose, and do not provide reliable constriction of the blood flow. Each of these methods can be difficult for the operating surgeon to put in place and position correctly, especially if passing through a small foramen. Such methods also do not consider reducing the likelihood of damage to surrounding tissue when positioning or applying pressure to the physiological structure. They are not easily loosened or tightened during surgery, which may be necessary to avoid complications during surgery. The methods also do not provide for a visual indication of the tension or pressure applied to the physiological structure, which may be particularly important in minimally invasive laparoscopic and robotic surgeries.

[0009] Therefore, a specialised device that can effectively and reliably surround and constrict a physiological structure during different types of surgery is required. It is desired to address the drawbacks associated with current methods for controlling blood flow in surgery.

[0010] SUMMARY

[0011] According to a first aspect of the present invention, there is provided a constriction device for use in surgery to surround a physiological structure, comprising: a strip having a main body, a first end and a second end opposite the first end; wherein the first end has a passageway therethrough configured to receive the second end and engage the main body and thereby form a fixed loop, wherein the passageway is provided at an angle to the main body such that, in use, the second end extends therefrom, toward the main body and lies substantially flat against the loop, along the length of the main body, and wherein the strip comprises a visual indicator to visually determine the size of the fixed loop.

[0012] The constriction device is a specialised device to surround a physiological structure during surgery. The strip forms a fixed loop, which is used to apply pressure effectively and reliably to the physiological structure. A passageway in the first end of the strip engages the second end which means that the device is simply to apply for a surgeon and is fixed in place to act as a constriction device. Providing a passageway means that the device can also be tightened or loosened easily by a surgeon. The passageway is provided at an angle to the main body. This means that, in use, the second end extends toward the main body or the first end and therefore does not substantially project outwardly away from the loop in use. This means that damage to surrounding tissue may be reduced during surgery.

[0013] The main body may be elongate and extend between the first end of the strip and the second end of the strip.

[0014] The main body is elongate which means that it can effectively surround a physiological structure and apply pressure to that structure.

[0015] The passageway may be provided at an angle of between 30 to 60 degrees relative to the main body.

[0016] Such an angle provides for the second end that has passed through the passageway to extends toward the main body or the first end, to minimise the degree to which first end projects away from the loop. This is advantageous as it reduces the space required for the device, reducing the likelihood of damage to surrounding tissue.

[0017] The passageway may be provided at an angle of less than 30 degrees or more than 60 degrees relative to the main body.

[0018] The passageway may comprise a first part and a second part, the cross section of the first part being larger than the cross section of the second part.

[0019] The first part of the passageway may be dimensioned to allow the second end and at least part of the main body to freely pass therethrough.

[0020] The second part of the passageway may be dimensioned to secure a part of the main body and thereby form a non-slip loop.

[0021] The passageway may be formed with first and second parts that differ in size. The first part allows for free movement of the second end and the main body therethrough, such that the device is easily applied. This makes it quicker and simpler for a surgeon to apply the device. The second part secures a part of the main body to form a non-slip loop, which means that the device can effectively and reliably apply pressure to the physiological structure during the surgery. The arrangement of the passageway means that a surgeon can readily and simply loosen or tighten the device, which is beneficial to effectively and safely control the blood flow as required during surgery.

[0022] The main body may be securable along the length of the main body to thereby form a fixed loop at a size suitable for the physiological structure.

[0023] The fixed loop may be formed at different sizes along the length of the main body. As such, the fixed loop may be formed at a range of anatomically relevant sizes, depending on the requirements.

[0024] The second end may comprise a guide hole configured to attach to a thread.

[0025] The second end may comprise a guiding tab.

[0026] The second end may comprise a guide hole or a guiding tab which may be used to guide the second end of the strip around the rear side of a physiological structure or through a small foramen. This may aid the surgeon with straightforward application of the device to ensure that it is positioned suitably to apply effective pressure to the physiological structure.

[0027] The second end may be narrower at a distal end furthest from the main body than at a part of the second end adjacent to the main body.

[0028] The second end being narrower may be beneficial during application of the band as it will fit more easily and smoothly around the physiological structure, and more easily pass through the passageway in the first end.

[0029] The main body may have a rounded cross section.

[0030] A rounded cross section of the main body may ensure that even pressure is applied to the physiological structure. This may assist with more effective and reliable control of blood flow. One or both of the first and second ends of the strip may be rounded in one or more dimensions.

[0031] By providing rounded first and second ends of the strip, the likelihood of damage to surrounding tissues during application of use of the device may be reduced.

[0032] The first end may comprise a gripping tab. The gripping tab may have a textured surface.

[0033] The strip may comprise an elastic material.

[0034] Elasticity of the strip may assist with ensuring that the device can be tightly secured around the physiological structure to apply suitable pressure to occlude blood flow.

[0035] The visual indicator may comprise measurement markings arranged along the length of the main body and / or on the second end.

[0036] The visual indicator may comprise a mechanochromic material in the main body, wherein the mechanochromic material changes colour or shade when the main body is stressed.

[0037] By providing a visual indicator to visually determine the size of the fixed loop, the operating surgeon can easily see the degree of pressure or tension applied to the physiological structure. This may mean that the blood flow can be controlled safely. This may also be particularly advantageous during robotic surgery where there is an absence of haptic feedback for the surgeon.

[0038] The strip may be formed of one or more materials with varying stiffness.

[0039] A part of the strip may be formed of a firmer or more rigid material than a part of which may be formed of a more flexible material. This may allow for smooth and simplified positioning of the strip, as well as preventing tissue injury when forming and tightening the loop. According to a second aspect of the present invention, there is provided a method of using the device of the first aspect, comprising: passing the second end of the strip around a part of a physiological structure; receiving the second end through the passageway in the first end of the strip; and pulling the second end such that the passageway engages the main body, thereby forming a fixed loop around the physiological structure, wherein the passageway is provided at an angle to the main body such that, in use,

[0040] By using a device in the method that is specifically designed for purpose, the method provides for a reliable and safe constriction of blood flow or surgical use. The device is easily and quickly applied by a surgeon, with likelihood of damage to surrounding tissue being reduced.

[0041] The method may further comprise tightening the device by pulling the second end further, such that the loop is formed with a smaller diameter.

[0042] The method may further comprise loosening the device by disengaging the main body in the passageway so that the main body passes back through the passageway.

[0043] The method may include loosening or tightening the device by moving the main body through the passageway. This is simple and quick for the surgeon to implement, which may be important in time-pressured surgery.

[0044] According to a third aspect, there is provided the device of the first aspect for use in liver surgery to surround the hepatoduodenal ligament.

[0045] According to a fourth aspect, there is provided the method of the third aspect for use in liver surgery to surround the hepatoduodenal ligament.

[0046] According to a third aspect of the present invention, there is provided a constriction device for use in surgery to surround a physiological structure, comprising: a strip having a main body, a first end and a second end opposite the first end; wherein the first end has a passageway therethrough configured to receive the second end and engage the main body and thereby form a fixed loop, wherein the passageway is provided at an angle to the main body such that, in use, the second end extends therefrom, toward the main body. It will be understood that any of the features of the first aspect may be combined with the features of the third aspect, and vice versa.

[0047] BRIEF DESCRIPTION OF THE FIGURES

[0048] Embodiments of the invention will now be described by way of example only with reference to the figures, in which:

[0049] Figure 1 shows a plan view of a first example of a constriction device for use in surgery;

[0050] Figure 2 shows a schematic drawing of a second example of a constriction device for use in surgery, in use;

[0051] Figure 3 shows a schematic drawing of the second example of a constriction device for use in surgery and surrounding a physiological structure; and

[0052] Figure 4 schematically shows the steps in a method of using the device.

[0053] DETAILED DESCRIPTION

[0054] In brief overview, a constriction device for use in surgery to surround a physiological structure, comprises a strip having a main body, a first end and a second end opposite the first end. The first end has a passageway therethrough configured to receive the second end and engage the main body and thereby form a fixed loop. The passageway is provided at an angle to the main body such that, in use, the second end extends therefrom, toward the main body or the first end.

[0055] Figure 1 shows a constriction device 100 for use in surgery. The device 100 comprises a strip 101. The strip has a main body 102, a first end 110 and a second end 120. The first end 110 and the second end 120 are on opposing sides of the main body 102 of the strip 101. The strip 101 may be integrally formed.

[0056] The main body 102 is elongate. It extends between the first end 110 and the second end 120 of the strip 101. The main body 102 may be flexible. That is, the main body 102, may be bendable around a physiological structure.

[0057] The main body 102 has a cross section has a rounded cross section. The cross section of the main body 102 may be rounded in one or more dimensions. For example, the cross section of the main body 102 may be circular, oval, or semicircular. Advantageously, an absence of vertex in the cross section may mean that damage to the physiological structure or nearby tissue in use may be minimised. The cross section of the main body 102 may be consistent along the length of the main body 102. Advantageously, this may mean that pressure for constriction of a physiological structure may be applied evenly. In examples, the cross section of the main body 102 may not be rounded and may instead be a different polygonal shape.

[0058] In examples, the dimensions of the cross section of the main body 102 may vary along the length of the main body 102. In examples, the cross section of the main body 102 may comprise notches 104. The notches 104 may be evenly spaced along the length of the main body 102. Advantageously, the notches 104 may provide for distinct and regular engagement points in use.

[0059] The first end 110 of the strip 101 has a passageway 112 therethrough. In use, the passageway 112 in the first end 110 may receive the second end 120 of the strip 101 , thereby forming a loop. The main body 102 may also pass through the passageway and engage with the passageway 112 such that the strip 101 forms a fixed loop.

[0060] The passageway 112 is provided at an angle to the main body 102. In examples, the passageway 112 may be provided at an angle of around 45 degrees relative to the main body 102. In examples, the passageway 112 may be provided at an angle of between 30 to 60 degrees relative to the main body 102. In examples, the passageway 112 may be provided at an angle of less than 30 degrees relative to the main body 102. In examples, the passageway 112 may be provided at an angle of more than 60 degrees relative to the main body 102. By providing the passageway 112 at an angle, the second end 120 that has passed through the passageway 112 extends from the passageway 112 toward the main body 102 or first end 110.

[0061] In the example shown in Figure 1 , this means that the part of the main body 102 and the second end 120 that have passed through the passageway lies substantially flat against the loop, along the length of the main body 102. As such, the second end 120 is tucked away and the likelihood of damage to surrounding tissue, in use, may be reduced. As shown in the embodiment shown in Figures 2 and 3, the passageway 112 may be provided at an angle, as described above, such that the second end 120 extends toward the first end 110. The second end 120 extends in the same plane as the first end 110 of the strip 101. This may reduce damage to nearby tissue as the second end 120 lies in the same plane of the loop so that the second end 120 does not project perpendicularly away from the passageway 112. Such an arrangement may also be easier for the operating surgeon to grip in order to easily loosen or tighten the loop if required.

[0062] In examples, the passageway 112 has a first part 114 and a second part 116. This is illustrated in the embodiments shown in each of Figures 1 to 3. The cross section of the first part 114 of the passageway 112 is larger than the cross section of the second part 116 of the passageway 112. In other words, the dimensions in one or more directions of the first part 114 may be greater than the dimensions in one or more directions of the second part 116.

[0063] The first part 114 of the passageway 112 is configured to receive the second end 120 and part of the main body 102 of the strip 101. The first part 114 is dimensioned such that the second end 120 and part of the main body 102 of the strip

[0064] 101 can pass freely therethrough. In examples, the first part 114 of the passageway 112 is slightly wider than the cross section of the main body 102. Advantageously, this means that the loop can be readily loosened or tightened in use.

[0065] The second part 116 of the passageway 112 is configured to engage the main body 102. In use, the second part 116 may fit tightly around the main body 102 to secure the loop in a fixed position and at a fixed size, i.e. to form a non-slip loop. In examples, the second part 116 of the passageway 112 is slightly narrower than the cross section of the main body 102. Advantageously, this means that the loop is securely fixed in size and position.

[0066] The main body 102 may be fixed in the second part 116 of the passageway 112 anywhere along the length of the main body 102 to form a fixed loop at a size suitable for the physiological structure 300. This is shown in Figure 3, where the main body

[0067] 102 is passing through the passageway 112 at the first part of the passageway 114. To secure the fixed loop, the main body 102 is engaged with the second part 116 of the passageway 112 to form a fixed loop around the physiological structure 300. In the example illustrated in Figure 3, the second end 120 that passes through the first part 114 of the passageway 112 extends from the passageway 112, toward the first end 110, in the plane of the first end 110.

[0068] Referring to the example illustrated in Figure 1 , in use, the second end 120 extends from the passageway 120 toward the main body 102. The second end 120 and a part of the main body 102 that passes through the passageway 112 extends and aligns along a part of the length of the main body 102 in the loop. Advantageously, this means that the part of the main body 102 and the second end 120 are aligned with the loop such that they are tucked away. This may be suitable where space in the area close to the physiological structure is tight.

[0069] In examples, the main body may be fixed in the passageway 112 close to the first end 110 of the strip 101 where a tight loop is required. In examples, the main body 102 may be fixed close to the second end 120 if a larger loop is required. Advantageously, being able to fix the loop along the length of the main body 102 means that suitable pressure may be applied to the physiological structure 300 as desired by the operating surgeon.

[0070] In examples, the passageway 112 may be provided having an inside surface. That is, the inside surface may be the part of the passageway 112 that contacts the part of the main body 102 and the second end 120. In examples, at least part of the inside surface of the passageway 112 may be textured. For example, the inside surface may have a textured surface, for example comprising a criss-cross pattern or protrusions thereon. Advantageously, this may reduce slippage of the fixed loop and my improve handling of the loop.

[0071] The first end 110 of the strip 101 may comprise a gripping tab 118. This may be provided to hold the first end 110 as the second end 120 is received in the passageway 112. Advantageously, this may make it easier for the operating surgeon to hold the passageway 112 in position as the second end 120 is passed therethrough.

[0072] In examples, the gripping tab 118 may be flat. In examples, the gripping tab 118 has a textured surface. The textured surface may comprise serrations 119, as shown in Figure 1. Two or more serrations 119 may be provided in the gripping tab 118. Advantageously, this may provide the operating surgeon increased grip of the first end 110. This may provide the operating surgeon with a non-slip surface to grip between their thumb and index finger in open operations, with similar non-slip grip when holding robotic or laparoscopic instruments.

[0073] The second end 120 of the strip 101 may comprise a guide hole 122. The guide hole 122 may be arranged for attachment to a separate thread. In use, a thread may be attached to the device 100 via the guide hole 122. The thread may be used to guide the support through a foramen to position the device 100. In examples, a guiding tab may be provided instead of the guide hole 122. The guiding tab may be used for an operating surgeon to grip on to the second end 120 of the strip 101 for positioning in use.

[0074] The second end 120 may be narrower at distal end 124 from the main body 102 than at a part of the second end 120 adjacent to the main body 102. In examples, the second end 120 may taper towards the distal end 124. In examples, there may be a step change in the cross section of the second end 120. Advantageously, a narrower distal end 124 in the second end 120 may make it easier to pass the second end 120 through the passageway 112 in use.

[0075] The first end 110 may be rounded in one or more dimensions. In examples, the first end 110 may have smooth edges and no, or few, vertices. The second end 120 may additionally or alternatively be rounded in one or more dimensions. This means that the second end may have smooth edges. Advantageously, by providing rounded first and second ends, the device may be positioned in an atraumatic manner, and damage or injury to surrounding tissue when the device is in use may be reduced.

[0076] The strip 101 may be provided in a range of sizes, suitable for a range of applications in the body. For example, the strip 101 may be dimensioned for use in liver surgery for hepatic portal blocking. In this example, the strip 101 may have a total length of between 100mm and 200mm. In examples, the strip 101 may have a total length of around 16 cm. The main body 102 may have a length of between 40mm and 150mm. In examples, the main body 102 may have a length of 90mm. The diameter of the cross section of the main body 102 may be between 3mm and 15mm. In examples, the total length of the strip 101 may be less than 100mm. In examples, the total length of the strip may be greater than 200mm. In examples, the main body 102 may have a length of less than 40mm. In examples, the main body 102 may have a length of more than 150mm. In examples, the diameter of the cross section of the main body 102 may be less than 3mm or greater than 15mm. Any of the exemplary dimensions of the strip 101 may be combined, as appropriate for the application of the constriction band 100 and for appropriate surrounding of a physiological structure.

[0077] The strip 101 may comprise an elastic material. Advantageously, this means that the device 100 can be stretched and tightly secured around the physiological structure to apply pressure to effectively occlude blood flow.

[0078] In examples, the first end 110, main body 102, and second end 120 of the strip

[0079] 101 is formed of the same elastic material. In examples, part of the strip 101 is formed of an elastic material. The elastic material may be a medical grade polymer or silicone material. In examples, at least part of the strip 101 may be formed from polyethylene, polypropylene, or a polymeric composition. Advantageously, such materials may have improved biological acceptability for medical use. In examples, at least part of the device 100 may comprise a silicone coated material, for example a silicone coated elastic material.

[0080] In examples, the strip 101 may be formed of materials with varying stiffness. In examples, the second end 120 may be formed of a firmer or more rigid material than the first end 110 which may be formed of a more flexible material. In examples, the second end 120 and part of the main body 102 adjacent to the second end 120 may be formed of a more firm or rigid material. In examples, at least half of the main body

[0081] 102 may be formed of such a material. Advantageously, this may allow for smooth and simplified sliding of the strip 101 through a small foramen in use. In examples, the firmer second end 120 may be guided though a small foramen behind a physiological structure 300 using its stiffness to guide in an atraumatic manner. In examples, the first end 110 may be formed of a firmer material than the second end 120. This may reduce tissue injury when forming the loop.

[0082] The main body 102 of the strip 101 may comprise a visual indicator. In use, the visual indicator may be used by the operating surgeon to determine and keep track of the force applied to apply the fixed loop to the desirable effect. This may be important to ensure and monitor safe use of the device 100 during surgery. Advantageously, a visual indicator may be of particular benefit in robotic surgeries where the operating surgeon does not have tactile sensation or haptic feedback and relies on visual cues or indicators during surgery.

[0083] In examples, the visual indicator may comprise a mechanochromic material in the main body 102. A mechanochromic material changes colour or shade when stressed. When used in the main body 102, the mechanochromic material changes colour when the main body 102 is stretched. This may provide a visual indication to the operating surgeon on the degree of stretch to determine whether the strip 101 is surrounding the physiological structure as tightly as desired.

[0084] In examples, the visual indicator may comprise measurement markings along the length of the main body 102. Such measurement markings may allow for the operating surgeon to determine the size of the fixed loop. Advantageously, this may provide additional assurance and accurate determination to the surgeon of the size of the loop. Measurement markings may be provided in place of, or in addition to, a mechanochromic material in the main body 102.

[0085] In examples, the second end 112 may comprise measurement markings. In use, when the strip 101 is stretched, the distance between the sizing markings increases. Advantageously, this may provide the operating surgeon with a visual indication of the degree of tension applied to the loop. This may be provided in place of, or in addition to, visual markings on the main body 102.

[0086] In examples, the passageway 112 may be formed as one part. The first end 110 comprising the passageway 112 may be formed of an elastic material. The second end 120 and the main body 102 may pass through the passageway 112 by stretching the elastic material of the first end 110 to widen the passageway. An additional tab may be provided at the first end 110 to assist in widening the passageway 112. The main body 102 may be secured in position to form a fixed loop by releasing part of the first end 112 such that a tight fit with the main body 102 is provided. The device 100 is suitable for use in different types of surgery where control of blood flow by surrounding a physiological structure is required. The device may be suitable for use in surgery on humans as well as in veterinary surgeries.

[0087] Referring to Fig. 4, a method 200 of using the device 100 is shown.

[0088] At step 201, the second end 120 of the strip 101 is passed around a part of a physiological structure or through a foramen behind a physiological structure. The distal end 124 of the second end 120 is the leading end. In examples, prior to passing the strip around the part of a physiological structure, a thread may be attached to the guide hole 122 to help with this step. In examples, the operating surgeon may use a guiding tab to hold for passing the second end 120 around the part of a physiological structure. In examples, the second end 120 may be passed around the back of a hepatoduodenal ligament during liver surgery.

[0089] At step 202, the second end 120 is received in the passageway 112 in the first end 110 of the strip 101.

[0090] At step 203, the second end 120 is pulled such that the passageway 112 engages the main body 102. The second end 120 and part of the main body 102 pass through the passageway. In examples, the second end 120 and part of the main body 102 freely pass through a first part 114 of the passageway. The second part 116 of the passageway 112 engages the main body 102 to form a fixed loop. As such, the physiological structure is constricted.

[0091] In the fixed loop, the second end 120 extends from the passageway 120, toward the main body 102 or the first end 110. As such, the second end 120 lies flat toward the first end 110 or the main body 102, thereby reducing the likelihood of damage to surrounding tissue.

[0092] Optionally, at step 204, the constriction device 100 may be tightened. The second end 120 is pulled further. The main body 102 may be engaged with the passageway at a point closer to the first end 110 such that the fixed loop is formed around the physiological structure with a smaller diameter. At step 205, the device 100 may be loosened. The main body 102 may be disengaged from the passageway 112. In examples, the main body 102 may be moved towards the first part 114 of the passageway 112 such that it can move freely through the passageway. The main body 102 may pass back through the passageway 112. The main body 102 may be engaged with the passageway at a point further from the first end 110 such that the fixed loop is formed around the physiological structure with a larger diameter.

[0093] Steps 204 and 205 may be repeated by the operating surgeon during the surgery as required. Advantageously, these steps are simple and quick to execute which may be important if surgery, and action during surgery, is time pressured.

[0094] At step 206, the device 100 may be removed from around the physiological structure. As in step 205, the device 100 may be loosened from around the physiological structure. Both the main body 102 and the second end 120 may pass back through the passageway 112 such that the strip 101 is no longer a fixed loop. The second end 120 may be passed back around the physiological structure such that it can be fully removed.

[0095] Although a few example embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

[0096] Attention is directed to all papers and documents which are filed concurrently with or before this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0097] All the features disclosed in this specification, including any accompanying claims, abstract and drawings, and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

[0098] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification, including any accompanying claims, abstract and drawings, or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS1 . A constriction device for use in surgery to surround a physiological structure, comprising: a strip having a main body, a first end and a second end opposite the first end; wherein the first end has a passageway therethrough configured to receive the second end and engage the main body and thereby form a fixed loop, wherein the passageway is provided at an angle to the main body such that, in use, the second end extends therefrom, toward the main body and lies substantially flat against the loop, along the length of the main body, and wherein the strip comprises a visual indicator to visually determine the size of the fixed loop.

2. The device of claim 1 , wherein the main body is elongate and extends between the first end of the strip and the second end of the strip.

3. The device of claim 1 or claim 2, wherein the passageway is provided at an angle of between 30 to 60 degrees relative to the main body.

4. The device of claim 1 to claim 3, wherein the passageway comprises a first part and a second part, the cross section of the first part being larger than the cross section of the second part.

5. The device of claim 4, wherein the first part of the passageway is dimensioned to allow the second end and at least part of the main body to freely pass therethrough.

6. The device of claim 4 or claim 5, wherein the second part of the passageway is dimensioned to secure a part of the main body and thereby form a non-slip loop.

7. The device of claim 6, wherein the main body is securable along the length of the main body to thereby form a fixed loop at a size suitable for the physiological structure.

8. The device of any preceding claim, wherein the second end comprises: a guide hole configured to attach to a thread, ora guiding tab.

9. The device of any preceding claim, wherein the second end is narrower at a distal end furthest from the main body than at a part of the second end adjacent to the main body.

10. The device of any preceding claim, wherein the main body has a rounded cross section.

11. The device of any preceding claim, wherein one or both of the first and second ends of the strip is rounded in one or more dimensions.

12. The device of any preceding claim, wherein the strip comprises an elastic material.

13. The device of any preceding claim, wherein the visual indicator comprises measurement markings arranged along the length of the main body and / or on the second end.

14. The device of claim 13, wherein the visual indicator comprises a mechanochromic material in the main body, wherein the mechanochromic material changes colour or shade when the main body is stressed.

15. The device of any of claims 1 to 14, for use in liver surgery to surround the hepatoduodenal ligament.

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