WO2016049676A1

WO2016049676A1 - Surgical cutting device and methods of use thereof

Info

Publication number: WO2016049676A1
Application number: PCT/AU2014/000956
Authority: WO
Inventors: Matthew Sampson; James Hopkins
Original assignee: Matthew Sampson; James Hopkins
Priority date: 2014-10-03
Filing date: 2014-10-03
Publication date: 2016-04-07

Abstract

The present disclosure relates to a surgical cutting device and methods of cutting a structure using the device. Certain embodiments of the present disclosure provide a surgical cutting device, the device comprising: (i) a cannula for internally receiving a stylet, the cannula comprising at a distal end an angled tip, the angled tip of the cannula comprising one or more cutting edges; (ii) a stylet receivable into the cannula, wherein the stylet comprises at a distal end an angled tip, the angled tip of the stylet comprising one or more cutting edges; and (iii) a body for holding the cannula, the body comprising means for positioning the stylet received in the cannula in a first position and in a second opposed position; wherein when the stylet is located in the first position the angled tip of the stylet is colocated with the angled tip of the cannula and when the stylet is located in the second position the angled tip of the stylet is located in an opposed position to the angled tip of the cannula.

Description

SURGICAL CUTTING DEVICE AND METHODS OF USE THEREOF

FIELD

[001] The present disclosure relates to a surgical cutting device and methods of cutting a structure using the device.

BACKGROUND

[002] There are a wide variety of diseases, condition and states whose treatment involves division, cutting or release of an involved structure.

[003] Typically these conditions are treated by way of some form of surgical procedure. For example, a variety of surgical procedures provide therapeutic benefit by division of connective tissue structures such as retinacula, ligaments or tendons. Common examples include carpal tunnel release for median nerve impingement, annular pulley release for trigger finger, plantar fascia release, lateral release of the elbow, psoas tenotomy for psoas impingement and tendon division for conditions resulting in spastic muscular contractures.

[004] Surgical treatments involving division, cutting or release of connective tissue structures often require the use of invasive techniques and are typically conducted in an operating theatre under general anaesthesia. As such, there is often an associated increase in morbidity and cost associated with conducting an open procedure, a high degree of technical skill required of the personnel involved with the procedure and the issues of length of hospital stay and the possibility of complications.

[005] For these reasons there is a need for procedures that are less invasive and/or which can assist with reducing morbidity, costs and complications.

[006] The present disclosure relates to a device, and method of use of the device, that provides a less invasive means of treating a variety of conditions requiring division, cutting or release of an involved structure. SUMMARY

[007] The present disclosure relates to a surgical cutting device and methods of cutting a structure using the device.

[008] Certain embodiments of the present disclosure provide a surgical cutting device, the device comprising:

a cannula for internally receiving a stylet, the cannula comprising at a distal end an angled tip, the angled tip of the cannula comprising one or more cutting edges;

a stylet receivable into the cannula, wherein the stylet comprises at a distal end an angled tip, the angled tip of the stylet comprising one or more cutting edges; and

a body for holding the cannula, the body comprising means for positioning the stylet received in the cannula in a first position and in a second opposed position, wherein when the stylet is located in the first position the angled tip of the stylet is colocated with the angled tip of the cannula and when the stylet is located in the second position the angled tip of the stylet is located in an opposed position to the angled tip of the cannula.

[009] Certain embodiments of the present disclosure provide a surgical cutting device, the device comprising:

a body for holding the cannula;

wherein the body of the cannula is adapted to locate the stylet in a first position and in a second opposed position, wherein when the stylet is located in the first position the angled tip of the stylet is colocated with the angled tip of the cannula and when the stylet is located in the second position the angled tip of the stylet is located in an opposed position to the angled tip of the cannula. [0010] Certain embodiments of the present disclosure provide a surgical method of cutting a structure, the method comprising using a surgical cutting device as described herein.

[0011] Certain embodiments of the present disclosure provide a surgical cutting method of cutting a structure, the method comprising:

inserting into a subject a surgical cutting device as described herein to a desired site of cutting of a structure, wherein the stylet is located in the first position; repositioning the stylet from the first position to the second position; and cutting the structure with the surgical cutting device.

[0012] Certain embodiments of the present disclosure provide a cannula for receiving a stylet, the cannula comprising:

(i) an angled tip at a distal end, wherein the angled tip comprises one or more cutting edges; and

(ii) a body for holding the cannula, wherein the body comprises means for positioning a stylet with an angled cutting tip in a first position and means for positioning the stylet in a second opposed position, wherein the means for positioning a stylet in the first position colocates the angled cutting tip of the stylet with the angled tip of the cannula and the means for positioning a stylet in a second position locates the angled cutting tip of the stylet in a position opposed to the angled tip of the cannula.

[0013] Certain embodiments of the present disclosure provide a cannula for receiving a stylet, the cannula comprising:

(ii) a body for holding the cannula, wherein the body comprises a first notch and a second opposed notch, the first notch positioned so that when a projection on a stylet is received in the first notch an angled distal tip of the stylet is colocated with the angled cutting tip of the cannula and when the projection on a stylet is received in the second notch the angled distal tip of the stylet is located opposed to the angled tip of the cannula. Certain embodiments of the present disclosure provide a cannula for receiving the cannula comprising:

(i) an angled tip at a distal end, wherein the angled tip comprises an open face and the angled tip comprises one or more cutting edges; and

(ii) a body for holding the cannula comprising a first notch and an opposed second notch, wherein the first notch is positioned on the body on a cylindrical polar axis of the cannula substantially perpendicularly to the open face of the angled tip.

[0015] Certain embodiments of the present disclosure provide a surgical method of cutting a structure, the method comprising using a surgical cutting device as described herein.

[0016] Certain embodiments of the present disclosure provide a method of forming a surgical cutting device from a biopsy needle comprising a cannula and a stylet, the method comprising:

(i) providing a biopsy needle, the biopsy needle comprising: (a) a cannula for receiving a stylet, the cannula comprising at a distal end an angled tip, the angled tip of the cannula comprising one or more cutting edges; and (b) a stylet receivable into the cannula, wherein the stylet comprises at a distal end an angled tip, the angled tip of the stylet comprising one or more cutting edges; and

(ii) repositioning the stylet received in the cannula to a position whereby the angled tip of the stylet is opposed to the angled tip of the cannula, thereby forming a surgical cutting device.

[0017] Other embodiments are disclosed herein. BRIEF DESCRIPTION OF THE FIGURES

[0018] Certain embodiments are illustrated by the following figures. It is to be understood that the following description is for the purpose of describing particular embodiments only and is not intended to be limiting with respect to the description.

[0019] Figure 1 shows the disassembled components of a stylised surgical cutting device according to one embodiment.

[0020] Figure 2 shows a stylised view of the tips of the cannula (1A) and the stylet (Figure IB) according to one embodiment.

[0021] Figure 3 shows a stylised side view of a surgical cutting device with the components assembled in a non-cutting/insertion configuration (Fig. 3A) and a cutting configuration (Fig. 3B), according to one embodiment.

[0022] Figure 4 shows a stylised view of a cannula component of a surgical cutting device according to one embodiment.

[0023] Figure 5 shows a stylised view of a surgical cutting device according to one embodiment, in which the stylet has been partially inserted into the cannula.

[0024] Figure 6 shows a modified 5 cm 18G needle hub demonstrating the creation of a newly created notch.

[0025] Figure 7 shows a modified 18G needle V shaped cutting tip, photograph and line diagrammatic representation. A 'V tip is created by turning stylet 180 degrees, stylet then locked in modified configuration using the newly created notch in needle hub.

[0026] Figure 8 shows a sonographic view of porcine common calcaneal tendon viewed in transverse plane

[0027] Figure 9 shows a sonographic view of porcine common calcaneal tendon in longitudinal plane post tenotomy, noting the deep central cleft. [0028] Figure 10 shows an open dissection demonstrating division of porcine common calcaneal tendon with scant remnant superficial paratenon fibres.

DETAILED DESCRIPTION

[0029] The present disclosure relates to a surgical cutting device and methods of cutting a structure using the device.

[0030] Certain disclosed embodiments have one or more combinations of advantages. For example, some of the advantages of the embodiments disclosed herein include one or more of the following: a device and/or method that can be used to treat some forms of diseases, conditions or states associated with tendon and connective tissue pathology whose treatment involves division, cutting or release of the involved structure; a device and/or method that has reduced invasiveness; a device and/or method that permits, in some circumstance, the use of a surgical procedure that does not require anaesthesia and an operating theatre; a device and/or method that is less invasive that standard procedures; a device and/or method that assists in reducing the morbidity and/or cost associated with open surgical procedures; a device and/or method that may, in some circumstances, reduce the need for the use of general anaesthesia for some surgical procedures; and/or to provide a useful commercial choice. Other advantages of certain embodiments are disclosed herein.

[0031] The present disclosure is based upon the determination that an efficient surgical cutting device, particularly for use in the cutting of tendons, ligaments and other connective tissue structures, can be formed by a modification to a coaxial bevelled needle.

[0032] Certain embodiments of the present disclosure provide a surgical cutting device.

[0033] Certain embodiments of the present disclosure provide a surgical cutting device, the device comprising:

[0034] Certain embodiments of the present disclosure provide a surgical cutting device, the device comprising:

a body for holding the cannula;

wherein the body of the cannula is adapted to locate the stylet in a first position and in a second opposed position, wherein when the stylet is located in the first position the angled tip of the stylet is colocated with the angled tip of the cannula and when the stylet is located in the second position the angled tip of the stylet is located in an opposed position to the angled tip of the cannula.

[0035] In certain embodiments, the surgical cutting device is a device for cutting a connective tissue structure. Other types of structures are contemplated.

[0036] In certain embodiments, the surgical cutting device is a device for cutting a tissue, a tendon and/or a ligament. In certain embodiments, the surgical cutting device is a tenotomy device. [0037] In certain embodiments, the cannula is a rigid or a semi-rigid cannula. In certain embodiments, the cannula is composed of a material that is rigid or a semi-rigid material. Examples of rigid and semi-rigid materials include metals or rigid plastics.

[0038] In certain embodiments, the cannula is composed of a metal and/or a metal alloy. In certain embodiments, the cannula is composed of a non-ferromagnetic metal and/or metal alloy. In certain embodiments, the cannula is composed of stainless steel.

[0039] In certain embodiments, the angled tip of the cannula comprises a 20° to 50° bevel.

[0040] In certain embodiments, the angled tip of the cannula comprises a 20° to 50°, a 25° to 50° bevel, a 30° to 50° bevel, a 35° to 50° bevel, a 45° to 50° bevel, a 20° to 45° bevel, a 25° to 45° bevel, a 30° to 45° bevel, a 35° to 45° bevel, a 40° to 45° bevel, a 20° to 40° bevel, a 25° to 40° bevel, a 30° to 40° bevel, a 35° to 40° bevel, a 20° to 35° bevel, a 25° to 35° bevel, a 30° to 35° bevel, a 20° to 30° bevel, a 25° to 30° bevel, a 25° to 30° bevel, or about any of the aforementioned ranges. Other bevel angles are contemplated.

[0041] In certain embodiments, the angled tip of the cannula comprises a 25° (Chiba) bevel. In certain embodiments the angled tip of the cannula comprises a 45° (Turner) bevel.

[0042] In certain embodiments, the angled tip of the cannula comprises a substantially 25° (Chiba) bevel. In certain embodiments the angled tip of the cannula comprises a substantially 45° (Turner) bevel. In certain embodiments, the angled tip of the cannula comprises a 25° (Chiba) bevel or about that angle. In certain embodiments the angled tip of the cannula comprises a 45° (Turner) bevel or about that angle.

[0043] In certain embodiments, the one or more cutting edges of the angled tip of the cannula comprise sharpened edges of a bevel of the angled tip.

[0044] The angled tip of the cannula may have a suitable point style. Examples of point styles include a bias grind, a vet point, a lancet point, or a deflected point. Other types of point styles are contemplated. [0045] In certain embodiments, the one or more cutting edges of the angled tip of the cannula comprise sharpened edges of a bevel of the angled tip, for examples sharpened edges produced by machine grinding of the edges. In certain embodiments, the outside edges of the angled tip are sharpened, for example by machine grinding. In certain embodiments, the inside (luminal) edges of the angled tip are sharpened, for example by machine grinding. In certain embodiments, the outside edges and the inside edges of the angled tip are sharpened.

[0046] The cannula is adapted so as to be able to internally receiving a stylet. The gauge of the cannula and the length of the cannula may be selected by a skilled person for the purposes of the stylet to be received and the characteristics and/or positioning of the structure to be cut. Typically the cannula has a gauge in the range from 18 to 25, although other gauges are contemplated. The length of the cannula may be selected, and typically is in the range from 5 to 25 cm, although increased lengths may be selected for some applications, such as veterinary applications.

[0047] The stylet is adapted so as to be able to be internally received into the cannula. The gauge of the stylet and the length of the stylet typically will be matched to that of the gauge and length of the cannula to be used. Typically, the stylet is also in the form of a hollow needle.

[0048] In certain embodiments, the stylet is rigid or a semi-rigid. In certain embodiments, the stylet is composed of a material that is rigid or a semi-rigid material. Examples of rigid and semi-rigid materials include metals or rigid plastics.

[0049] In certain embodiments, the stylet is composed of a metal and/or a metal alloy. In certain embodiments, the stylet is composed of a non-ferromagnetic metal and/or metal alloy. In certain embodiments, the cannula is composed of stainless steel. In certain embodiments, the cannula and the stylet are composed of a non-ferromagnetic metal and/or metal alloy.

[0050] In certain embodiments, the angled tip of the stylet comprises a bevel angle that is matched to, or substantially the same as, the bevel angle of the cannula. In certain embodiments, the angled tip of the stylet comprises a bevel angle substantially the same as the angle of the bevel of the cannula.

[0051] In certain embodiments, the angled tip of the stylet comprises a 20° to 50° bevel.

[0052] In certain embodiments, the angled tip of the stylet comprises a 20° to 50°, a 25° to 50° bevel, a 30° to 50° bevel, a 35° to 50° bevel, a 45° to 50° bevel, a 20° to 45° bevel, a 25° to 45° bevel, a 30° to 45° bevel, a 35° to 45° bevel, a 40° to 45° bevel, a 20° to 40° bevel, a 25° to 40° bevel, a 30° to 40° bevel, a 35° to 40° bevel, a 20° to 35° bevel, a 25° to 35° bevel, a 30° to 35° bevel, a 20° to 30° bevel, a 25° to 30° bevel, a 25° to 30° bevel, or about any of the aforementioned ranges. Other bevel angles are contemplated.

[0053] In certain embodiments, the angled tip of the stylet comprises a 25° (Chiba) bevel. In certain embodiments the angled tip of the stylet comprises a 45° (Turner) bevel.

[0054] In certain embodiments, the angled tip of the stylet comprises a substantially 25° (Chiba) bevel. In certain embodiments the angled tip of the stylet comprises a substantially 45° (Turner) bevel. In certain embodiments, the angled tip of the stylet comprises a 25° (Chiba) bevel or about that angle. In certain embodiments the angled tip of the stylet comprises a 45° (Turner) bevel or about that angle.

[0055] The stylet comprises at a distal end an angled tip comprising one or more cutting edges.

[0056] The angled tip of the stylet may have a suitable point style. Examples of point styles include a bias grind, a vet point, a lancet point, or a deflected point. Other types of point styles are contemplated.

[0057] In certain embodiments, the one or more cutting edges of the angled tip of the stylet comprise sharpened edges of a bevel of the angled tip. Examples of sharpened edges include machine ground edges. In certain embodiments, the outside edges of the angled tip are sharpened, for example by machine grinding. In certain embodiments, the inside (luminal) edges of the angled tip are sharpened, for example by machine grinding. In certain embodiments, the outside edges and the inside edges of the angled tip are sharpened.

[0058] The device comprises a body for holding the cannula. In certain embodiments, the body is composed of a material comprising a plastic. In certain embodiments, the body is composed of a material comprising a rigid plastic. Other types of materials are contemplated.

[0059] In certain embodiments, the body is composed of a plastic formed around the cannula.

[0060] In certain embodiments, the body holds the base of the cannula. In this embodiment, the body of the cannula is hollow and configured so as to allow the end of the stylet to be inserted into the body and subsequently inserted into the end of the cannula within the body. In certain embodiments, the body for holding the cannula is adapted to internally receive the stylet.

[0061] The body comprises means for positioning the stylet received in the cannula in a first position and in a second opposed position. In the first position the angled tip of the stylet is colocated with the angled tip of the cannula, and in the second position the angled tip of the stylet is located in an opposed position to the angled tip of the cannula. Colocation of the tips in the first position assists with insertion of the device into a subject to the desired site of cutting, and location of the tips in the opposed position forms a surgical cutting end.

[0062] In certain embodiments, the means for positioning comprises a mean for retaining the stylet. In certain embodiments, the means for positioning comprises an interference fit.

[0063] In certain embodiments, the body of the cannula and the stylet are adapted so as to locate the stylet in a first position and in a second opposed position, wherein when the stylet is located in the first position the angled tip of the stylet is colocated with the angled tip of the cannula and when the stylet is located in the second position the angled tip of the stylet is located in an opposed position to the angled tip of the cannula.

[0064] In certain embodiments, the means for positioning in the first and second positions comprise recesses or notches. In certain embodiments, the means for positioning in the first and second positions comprise recesses or notches in the body of the cannula. In certain embodiments, the body of the cannula comprises recesses or notches for positioning the stylet.

[0065] In certain embodiments, the stylet comprises a projection receivable by the body of the cannula to locate the stylet in the first or the second position. In certain embodiments, the projection comprises a finger. In certain embodiments, the projection projects in a direction substantially parallel to the stylet. In certain embodiments, the projection projects in a direction substantially perpendicular to the stylet. Other configurations are contemplated.

[0066] Other means for positioning are contemplated.

[0067] Certain embodiments of the present disclosure provide a surgical cutting device, the device comprising:

a body for holding the cannula, the body comprising a first recess and a second opposed recess receivable by a projection on the stylet, wherein the first recess is positioned so that when the projection on the stylet is received in the first recess the angled distal tip of the stylet is colocated with the angled cutting tip of the cannula and when the projection on the stylet is received in the second recess the angled distal tip of the stylet is located opposed to the angled tip of the cannula.

[0068] In certain embodiments, the body for holding the cannula comprises a base. In certain embodiments, the body for holding the cannula comprises a base and the means for positioning the stylet are located at the base of the body. In certain embodiments, the base comprises recesses or notches for positioning the stylet.

[0069] In certain embodiments, the base comprises a first recess and a second opposed recess, and the stylet comprises a projection receivable into the first recess or the second recess. In certain embodiments, the base comprises a first notch and a second notch, and the stylet comprises a projection receivable into the first notch or the second notch.

[0070] In certain embodiments, the stylet comprises a body for holding the stylet.

[0071] In certain embodiments, the body for holding the stylet is composed of a material comprising a plastic, a metal or a metal alloy. In certain embodiments, the body for holding the stylet is composed of a material comprising a rigid plastic. Other types of materials are contemplated.

[0072] In certain embodiments, the body is composed of a plastic formed around the stylet.

[0073] In certain embodiments, the stylet comprises a body for holding the stylet and the body holding the stylet comprises a projection. In certain embodiments, the projection projects in a direction substantially parallel to the stylet. In certain embodiments, the projection projections in a direction substantially perpendicular to the stylet.

[0074] In certain embodiments, the body holds the base of the stylet. In certain embodiments, the projection projects from the base of the stylet.

[0075] In certain embodiments, the body of the stylet comprises a projection and the means for positioning the stylet comprises a recess configured to receive the projection. In certain embodiments, the recess comprises a notch. In certain embodiments, the recess holds the projection. In certain embodiments, the recess and the projection form an interference fit.

[0076] In certain embodiments, a reversed configuration of the projection and recess/notches is utilised, whereby the body of the cannula comprises a finger projection which may be received by opposed recesses on the body of the stylet. [0077] In certain embodiments, the means for positioning the stylet received in the cannula in a first position and in a second opposed comprises a projection.

[0078] In certain embodiments, the means for positioning the stylet received in the cannula in a first position and in a second opposed comprises a projection, and the body of the stylet comprises two opposed recesses configured to receive the projection. In certain embodiments, the recesses comprise notches. In certain embodiments, the recesses hold the projection. In certain embodiments, the recesses and the projection form an interference fit.

[0079] In certain embodiments, the means for positioning the stylet received in the cannula in a first position and in a second opposed position comprises a projection.

[0080] In certain embodiments, the stylet comprises a body and the body of the stylet comprises two opposed recesses configured to receive the projection.

[0081] Other of the means for position the stylet in a first position and a second position are contemplated.

[0082] Certain embodiments of the present disclosure provide a surgical cutting device, the device comprising:

a body for holding the stylet, the body comprising a first recess and a second opposed recess receivable by a projection on the cannula, wherein the first recess is positioned so that when the projection on the cannula is received in the first recess the angled distal tip of the stylet is colocated with the angled cutting tip of the cannula and when the projection on the cannula is received in the second recess the angled distal tip of the stylet is located opposed to the angled tip of the cannula. [0083] Certain embodiments of the present disclosure provide a surgical cutting device, the device comprising:

a stylet receivable into the cannula, wherein the stylet comprises at a distal end an angled tip, the angled tip of the stylet comprising one or more cutting edges; a body for holding the stylet, the body comprising a first recess and a second opposed recess; and

a body for holding the cannula, the body comprising a projection receivable by the first recess and the second recess on the body of the stylet;

wherein the first recess is positioned so that when the projection on the body of the cannula is received in the first recess the angled distal tip of the stylet is colocated with the angled cutting tip of the cannula and when the projection on the body of the cannula is received in the second recess the angled distal tip of the stylet is located opposed to the angled tip of the cannula.

[0084] Certain embodiments of the present disclosure provide a surgical method of cutting a structure.

[0085] Certain embodiments of the present disclosure provide a surgical method of cutting a structure, the method comprising using a surgical cutting device as described herein to cut the structure.

[0086] Methods for cutting structures are as described herein. Structures for surgical cutting are as described herein.

[0087] In certain embodiments, the structure comprises a connective tissue structure. Other types of structures are contemplated. In certain embodiments, the structure comprises a tendon and/or a ligament. In certain embodiments, the method is used to cut a tendon or a ligament. [0088] In certain embodiments, the method comprises inserting into a subject a surgical cutting device as described herein to a desired site of cutting of a structure.

[0089] In certain embodiments, the method comprises:

inserting into a subject a surgical cutting device as described herein to a desired site of cutting of a structure, wherein the stylet is located in the first position; repositioning the stylet from the first position to the second position, and cutting the structure with the surgical cutting device.

[0090] In certain embodiments, the method comprises a medical imaging guided method. In certain embodiments, the method comprises medical imaging guidance. In certain embodiments, the medical imaging guidance comprises ultrasound guidance.

[0091] Certain embodiments of the present disclosure provide a medical imaging guided method of cutting a connective tissue structure, the method comprising using a surgical cutting device as described herein.

[0092] In certain embodiments, the method comprises ultrasound guidance of the device to a position for cutting. In certain embodiments, the medical imaging guidance comprises ultrasound guidance of the device to a position for cutting.

[0093] Certain embodiments of the present disclosure provide a surgical cutting method of cutting a structure, the method comprising:

[0094] In certain embodiments, the method comprises ultrasound guidance of the device to the desired site of cutting. In certain embodiments, the structure to be cut comprises a tendon or a ligament. [0095] Certain embodiments of the present disclosure provide a surgical method of cutting a connective tissue structure, the method comprising:

inserting into a subject through the skin and under ultrasound vision or guidance, a surgical cutting device as described herein to a desired site of cutting of a structure, wherein the stylet is located in the first position;

repositioning the stylet from the first position to the second position; and cutting the structure with the surgical cutting device.

[0096] Certain embodiments of the present disclosure provide a cannula as described herein.

[0097] Certain embodiments of the present disclosure provide a cannula for receiving a stylet, the cannula comprising:

[0098] Certain embodiments of the present disclosure provide a cannula for receiving a stylet, the cannula comprising:

(ii) a body for holding the cannula, wherein the body comprises a first notch and a second opposed notch, the first notch positioned so that when a projection on a stylet is received in the first notch an angled distal tip of the stylet is colocated with the angled cutting tip of the cannula and when the projection on a stylet is received in the second notch the angled distal tip of the stylet is located opposed to the angled tip of the cannula. [0099] Certain embodiments of the present disclosure provide a cannula for receiving a stylet, the cannula comprising:

(ii) a body for holding the cannula, the body comprising a first notch and an opposed second notch, wherein the first notch is positioned on the body on a cylindrical polar axis of the cannula substantially perpendicularly to the open face of the angled tip.

[00100] Certain embodiments of the present disclosure provide a surgical method of cutting a structure using a cannula as described herein.

[00101] Certain embodiments of the present disclosure provide a product comprising a cannula as described herein and a stylet as described herein.

[00102] Certain embodiments of the present disclosure provide a product comprising:

(i) a cannula as described herein; and

(ii) a stylet receivable into the cannula, the stylet comprising an angled cutting tip and a projection receivable by recesses/notches on the body of the cannula.

[00103] Certain embodiments of the present disclosure provide a method of forming a surgical cutting device from a biopsy needle.

[00104] Certain embodiments of the present disclosure provide a method of forming a surgical cutting device from a biopsy needle comprising a cannula and a stylet, the method comprising:

[00105] The present disclosure is further described by the following examples. It is to be understood that the following description is for the purpose of describing particular embodiments only and is not intended to be limiting with respect to the above description.

EXAMPLE 1 - A surgical cutting device

[00106] Figure 1 shows the disassembled components of a stylised surgical cutting device 110 according to one embodiment.

[00107] Referring to Figure 1A, there is shown a front view of a cannula 112 and a stylet 114 for use in the surgical cutting device 110 for positioning a first position.

[00108] The cannula 112 is hollow and configured so as to be able to internally receive the stylet 114. The cannula 112 comprises a shaft 116 which is typically rigid and made of a metal or metal-alloy. The use of a non-ferromagnetic material (such as stainless steel) provides a number of benefits, including assisting in guidance of the device 110 to the desired site of cutting. Typically, the cannula 112 has a length of 5 to 20 cm and a 18 to 25 gauge, although other lengths and gauges are suitable.

[00109] The cannula 112 comprises at a distal end 118 an angled, bevelled tip 120 comprising one or more cutting edges. Typically, the tip of the cannula utilises a Chiba bevel which has a bevel angle of around 25°, although other types of bevelled tips may be utilised. The cannula 112 is hollow and permits the shaft of the stylet 123 to be received into the cannula 112. The one or more cutting edges of the angled tip of the cannula typically comprise sharpened edges.

[00110] The cannula 112 also comprises a body 122 which acts to hold the cannula. Typically, the body 122 is cylindrical or rectangular prismatic in shape and may comprise a head 124 for also holding the end of the shaft 116 of the cannula and a base 128. The body 122 is typically formed of a rigid plastic. The body 122 and head 124 also assist the user in holding and positioning the device. In the embodiment shown, the body 122 and head 124 are hollow and which permits the stylet 114 to be inserted through an opening 126 in the base 128 of the body 122, and pass through the body 122 into the shaft 116 of the cannula 112. In the embodiment show, the base 128 also comprises a circular flange 130 which runs around the outside of the base 128.

[00111] The flange 130 comprises two means for positioning the stylet 114 received in the cannula 112 in a first position or in a second opposed position. In the embodiment shown, the means for positioning the stylet are located at the base 128, in the flange 130, and comprise two opposed recesses (notches) cut into the flange 130 and configured to receive a projection 142 on the stylet 114.

[00112] Figure 1A is a front view and shows the first notch 132. This notch is located on the same side of the body 122 as the open face 134 of the tip 120 of the cannula, and is located in-line with the open face 134 of the angled tip 120. When the stylet is located in the first position it is in a configuration suitable for insertion of the device to a desired site of cutting. As such, the first notch 132 is positioned on the body 122 on a cylindrical polar axis of the cannula 122 substantially perpendicularly to the open face 134 of the angled tip 120.

[00113] The stylet 114 is configured to be receivable into the cannula 112 and comprises a shaft 123, which is also typically rigid and made of a metal or metal-alloy, such as a non-ferromagnetic material (eg stainless steel). The shaft 123 of the stylet 114 is typically hollow, and comprises at a distal end 136, an angled, bevelled tip 138 comprising one or more cutting edges. Typically, the tip 138 of the stylet has a bevelled angle that is the same, or substantially the same, as the tip 120 of the cannula. In this way, the angled tip 138 of the stylet may be able to be colocated with the angled tip 120 of the cannula 112, thereby sitting flush inside the tip 120, which provides a configuration suitable for insertion into a subject to the desired site of cutting.

[00114] The stylet 114 also comprises a body 140 for holding the stylet. Typically, the body 140 is formed of a rigid plastic and may comprise a head 144 for holding the end of the stylet 114. In the embodiment shown the head 144 comprises a conical shape which assists with the movement and guidance of the stylet 114 into the cannula body 122 through the opening 126.

[00115] The stylet 114 comprises a projection, in this case a finger 142, receivable by the body 122 to locate the stylet in the first or the second position. The finger 142 projects from the body for holding the stylet. In the embodiment shown, the projection projects in a direction substantially parallel to the stylet, although in other embodiments the projection may, for example, project in a direction substantially perpendicular to the stylet.

[00116] When the body 140 of the stylet is inserted into the base 128 of the cannula, and the finger 142 has been received by first notch 132, the tip 138 of stylet is positioned in a first position so as to be collocated with the tip 120 of the cannula, and the bevelled face of the stylet sits inside and flush with the bevelled face 134 of the tip 120. This provides a configuration of the device suitable for insertion into a subject to the desired site of cutting. Accordingly, the length of the shaft 122 is usually selected so that when the stylet 114 is inserted into the cannula 112, the tips 120 and 138 can be collocated.

[00117] Referring to Figure IB, there is shown a rear view of a cannula 112, and a stylet 114 for use in the surgical cutting device 110 for positioning in a second position.

[00118] In this position, the cannula 112 is shown positioned 180° to that shown in Figure 1A.

[00119] The cannula 112 comprises a shaft 116, and at a distal end 118, an angled, bevelled tip 120 as described above, except that the back face of the tip 120 is shown.

[00120] The cannula 112 comprises a body 122 and a head 124 which holds the end of the cannula shaft 116. The body 122 is hollow and permits the stylet 114 to be inserted through an opening 126 in the base 128 of the body 122, and pass through the body 122 to the shaft 116 of the cannula. The base 128 of the body 122 also comprises a flange 130 which runs around the outside of the cylindrical base 128. [00121] The flange 130 comprises two means (notches) for positioning the stylet 114 received in the cannula 112, which permit the stylet 114 received into the cannula 112 to be positioned in a first position or in a second opposed position. Figure IB shows a rear view of the cannula 112. In this view, the second notch 148 for locating the stylet 114 in a second position is visible. The second notch 148 is located opposed to the first notch 132 shown in Figure 1A. When the stylet 114 is positioned in this second position, the angle tip 138 of the stylet is located in an opposed position to the angled tip 120 of the cannula.

[00122] As such, in the rear view shown in the Figure IB, the flange 130 comprises a second notch 148 which extends into the flange 130. The second notch 148 is located directly opposed to notch 132 in Figure 1A, is located on the same side of the body 124 as the back side 150 of the tip 120, and thereby located in-line with the back side 150 of the angled tip 120.

[00123] As described, the stylet 114 comprises a shaft 123, which is hollow, and comprises at a distal end 136, an angled, bevelled tip 138. Typically, the tip 138 of the stylet has a bevelled angle that is the same, or substantially the same, as the tip 120.

[00124] The stylet 114 also comprises a body 140 and a head 144 for holding the end of the stylet shaft 123. To provide a configuration of the device for cutting (after the device has been guided to a desired site of cutting), the stylet 114 is withdrawn slightly from the cannula 112, thereby disengaging the finger 142 from the first notch 132. The stylet 114 is then rotated through 180° so that the finger 142 is aligned with the second notch 148 and re-inserted.

[00125] In this configuration, when the body 140 of the stylet is re-inserted into the base 128 of the cannula, and the finger 142 has been received by notch 148, the tip 138 of stylet is positioned so as to be opposed to the open face 134 of the tip. This provides a "V"-shaped configuration of the tips of the cannula and stylet (120 and 138 respectively) which is suitable for cutting a structure, such as a tendon.

[00126] In this way, the stylet 114 can be received in the cannula 112 in a first position (1A) or in a second opposed position (IB), and when the stylet is located in the first position the angled tip 138 of the stylet is colocated with the angled tip 120 of the cannula in a non-cutting position and when the stylet is located in the second position the angled tip 138 of the stylet is located in an opposed position to the angled tip 120 of the cannula in a cutting position.

[00127] As such, the body of the cannula is adapted to locate the stylet in a first position and in a second opposed position, so that when the stylet is located in the first position the angled tip of the stylet is colocated with the angled tip of the cannula and when the stylet is located in the second position the angled tip of the stylet is located in an opposed position to the angled tip of the cannula.

[00128] In an alternative embodiment as to that described above, the body of the cannula may have a projection (eg a finger) which is receivable by opposed recesses/notches on the body of the stylet. In this way, the projection on the body of the cannula may be received into a first recess on the body of the stylet, so as to collocate the angled tip of the stylet with the angled tip of the cannula. This position is suitable for insertion of the device to a desired site of cutting. When the projection on the body is received into the second opposed notch on the body of the stylet (located 180° to the first notch), the angled tip of the stylet is located in an opposed position to the angled tip of the cannula, thereby forming a "V"-shaped configuration of the tips of the cannula and the stylet, and which is suitable for cutting a structure, such as a tendon.

[00129] Figure 2 shows stylised, magnified views of the tips of the cannula (Figure 2 A) and the stylet (Figure 2B) according to one embodiment.

[00130] Referring to Figure 2 A, there is shown a distal end 218 of the cannula with a bevelled angled tip 220 at the end of the shaft 216. Typically, the angled tip 220 of the cannula comprises a 20° - 50° bevel, although other angles are contemplated. The angled tip 220 comprises a hollow face 250, sharpened edges 252 which typically are ground on both the external and internal sides of the bevel, and a pointed tip 254 which is typically also sharpened by grinding.

[00131] Referring to Figure 2B, there is shown a distal end 236 of the stylet with a bevelled angled tip 238 at the end of the shaft 223. The angled tip 238 comprises a face 256, sharpened edges 258 which typically are ground on both the external and internal sides, and a pointed tip 260 which is typically also sharpened by grinding. Typically, the angled tip 238 of the stylet comprises a bevel angle substantially the same as the angle of the bevel of the tip 220 of the cannula.

[00132] Figure 3 shows a stylised side view of a surgical cutting device 310 with the components assembled in a non-cutting/insertion configuration (Fig. 3A) and a cutting configuration (Fig. 3B), according to one embodiment.

[00133] Referring to Figure 3 A, there is shown side view of the device 310 in a configuration for insertion of the device into a subject. In this configuration, the tip of the cannula (320) and the tip of the stylet (not visible) are collocated 364.

[00134] The stylet 314 has been received into the cannula 312. The body 340 of the stylet 314 has been inserted fully into the body 322 of the cannula, so that the body 340 of the stylet contacts the base 362 of the flange 330. The projecting finger 342 is received into the first notch in the fiange 330 at the base 328 of the body 324 of the cannula. The receipt of the finger 342 by the first notch prevents any rotation of the stylet 314 inside the cannula 312 and places the tip 320 of the cannula and the tip of the stylet (not visible) into a position 364 where the tips are collocated and the bevelled face of the stylet sits inside and flush with the bevelled face of the of the tip 320 of the cannula. This provides a configuration of the device suitable for insertion into a subject to the desired site of cutting in a human or animal subject.

[00135] Referring to Figure 3B, there is shown side view of the device 310 in a configuration for cutting of a structure. In this configuration, the tips of the cannula (320) and the stylet (338) are located in a "V" shaped configuration 366 suitable for cutting.

[00136] The stylet 314 has been received into the cannula 312, but in an orientation 180° opposed to that shown in Figure 3A. The body 340 of the stylet 314 has been rotated and then re-inserted into the body 322 of the cannula. The finger 342 is now received into the second opposed notch in the flange 330. The receipt of the finger 342 by the notch prevents any rotation of the stylet 314 inside the cannula 312 and places the tip 320 of the cannula and the tip 338 of the stylet into a "V"-shaped configuration 366 which is suitable for cutting a structure, such as a tendon.

[00137] Figure 4 shows a view of a stylised view of the cannula 412 component of a surgical cutting device according to one embodiment.

[00138] The cannula 412 comprises a shaft 416. At a distal end 418, the cannula 412 comprises an angled, bevelled tip 420. The cannula 412 is hollow and permits the shaft of a stylet (not shown) to be received into the cannula 412.

[00139] The cannula 412 also comprises a body 422 having a head 424, which hold the end of the cannula shaft 416. The body 422 and head 424 permit the stylet to be inserted through an opening 426 in the base 428 of the body 422, and pass through the body 422 and head 424 to the shaft 416 of the cannula 412. The base 428 of the body 422 comprises a flange 430 which runs around the outside of the base 428.

[00140] The flange 430 comprises two opposed notches (432 and 448) in the flange 430 for positioning the stylet in either a first position or in a second opposed position. The first notch 432 is located on the same side of the body 424 as the open face of the tip 420 of the cannula 412. The second notch 448 is located 180° to the first notch.

[00141] When the stylet is located in a first position, by receipt of a finger projection on the stylet in the first notch 432, the device adopts a non-cutting configuration suitable for insertion into a subject to the desired site of cutting. When the stylet is located in a second position, by receipt of a finger projection on the stylet in the opposed second notch 448, the device adopts a configuration suitable for cutting a structure, such as a tendon.

[00142] Figure 5 shows a stylised view of surgical cutting device 510 according to one embodiment, in which the stylet 514 has been partially inserted into the cannula 512.

[00143] The cannula 512 comprises a shaft 516 which is hollow and capable of receiving the stylet 514. The stylet 514 is shown partially inserted into the body 524 of the cannula, through an opening 526 present in the base 528 of the body 524 of the cannula. The body 524 of the cannula comprises a flange 530 around the base 528 which comprises two notches, a first notch 532 and an opposed second notch (not visible).

[00144] The body 524 is hollow and permits the stylet 522 to be inserted through an opening 526 in the base 528 of the body 522, and pass through the body 524 to the shaft 516 of the cannula 512. The base 528 of the body 524 also comprises a circular flange 530 which runs around the outside of the cylindrical base 528.

[00145] In the embodiment shown, the flange 530 comprises two notches for positioning the stylet 514 received in the cannula 512 in a first position or in a second opposed position. In the figure, only the first notch 532 is visible. The first notch 532 is located on the same side of the body 524 as the open face of the tip of the cannula (not shown) and in-line with the open face of the tip of the cannula.

[00146] The stylet 514 comprises a body 540 having a head 544 for retaining the stylet 514. The body 540 of the stylet 514 also comprises a forward projecting finger 542 which is receivable by the first notch 532 in the flange 530 at the base 528 of the body 522 of the cannula.

EXAMPLE 2 - Development of a novel, percutaneous, ultrasound guided needle tenotomy technique

[00147] The following description relates to development of a novel, percutaneous, ultrasound guided needle cutting technique for division of tendons and other connective tissue structures.

[00148] Here we describe, using an animal cadaveric model, demonstration of the feasibility of a novel, percutaneous, ultrasound guided needle cutting technique. The technique involves the creation of an effective needle tenotomy device via an improvement to an 18G coaxial bevelled needle. The technique provides a less invasive approach with reduction of morbidity and cost associated with open procedures.

[00149] (i) Methods

[00150] We used the common calcaneal tendon of the porcine hind leg as a target for tenotomy. Porcine hind legs were sourced from a production animal wholesaler.

[00151] A linear array 12 MHz probe was used to provide ultrasound vision. Using a disposable scalpel, a small skin incision was made medial to the tendon 4 cm from its distal insertion. We made a modification to an 18g co-axial bevelled needle (Cook Medical 18g Chiba biopsy needle) to serve as a percutaneous cutting device. A small notch was cut into the hub of the needle such that the stylet could be inserted and fixed at 180° to its normal orientation (Figure. 6). This created a 'V shaped cutting tip (Fig. 7). Whilst kept in its conventional non-modified configuration, the needle was manoeuvred to the site of tenotomy. The needle was kept in this configuration (stylet bevel flush with the coaxial bevel) to minimise trauma to other tissues during positioning. This also allowed the bevel to be used to manipulate needle direction during manoeuvring, (turning the needle hub and bevel permitted changes in needle trajectory for subtle positioning adjustments).

[00152] With real time ultrasound guidance the needle was positioned at the deep aspect of the tendon. The stylet was then rotated 180° and locked into the cutting position using the opposed notch in the needle hub. The needle was oriented such that the inverted stylet bevel was positioned adjacent to the deep aspect of the tendon. Under ultrasound guidance, the 'V shaped cutting tip was repeatedly advanced and retracted in a sawing action through the various layers of tendon fibres to achieve tendon division. Progress was assessed in real time sonographically and subsequently evaluated with open dissection. The procedure was performed by a fellowship trained musculoskeletal radiologist adept at ultrasound guided intervention.

[00153] (ii) Results

[00154] The inverted 'V shaped cutting tip was found to be extremely effective in dividing the common calcaneal tendon. This was a thick structure, approximately 1.2 x 2 cm in transverse dimension (Fig. 8), however agitation through the tendon resulted in destruction of fibres in little time. Initial resistance rapidly dissipated with division of fibres. Direct ultrasound vision permitted selectivity, and the procedure began with the deep/anterior portion of the calcaneal tendon and progressed through fibres to reach the superficial/posterior portion. Cutting needle tip visualisation was able to be maintained throughout. Within approximately 3 minutes a large cleft was sonographically demonstrable (Fig. 9. Lengthening of the tendon was then possible. The entire procedure was completed in around 10 minutes. Open dissection subsequently confirmed the tendon to be almost completely divided with demonstration of some remnant superficial paratenon (Fig. 10). During open dissection we encountered no detectable injury to surrounding soft tissues.

[00155] (iii) Discussion

[00156] The cadaveric porcine common calcaneal tendon was chosen for this trial in part for accessibility but also to provide a large diameter, tough structure upon which to evaluate the technique. It was anticipated that needle tenotomy would prove difficult owing to its significant bulk. However, it was found that the 'V shaped tip created was extremely effective. The cutting device cut through tendon fibres readily and the 18g coaxial needle provided the requisite stiffness to push through such a tough structure. Without being bound by theory, it is believed that the primary cutting mechanism involved tendon fibres being drawn into, and cut by the 'V on the forward stroke. In addition, downward angulation of the needle hub on the backward stroke with resultant upward angulation of the sharp, inverted stylet bevel tip against the undersurface of the tendon probably contributed in part to fibre division. In addition, the tip did not accumulate cut tendon debris by virtue of clearing of this material on the backward stroke.

[00157] Under direct ultrasound vision it was possible to accurately target specific portions of the tendon. This is obviously desirable and confers the ability to perform selective, partial tenotomy or complete tendon division depending upon the intended outcome. Continuous direct vision of the tip was also reassuring in terms of restriction of injury to surrounding tissues. Given the ability to divide a structure of the calibre of the porcine common calcaneal tendon, there should be no difficulty in applying this technique to any of the larger tendons in the human body. The accuracy and selectivity of the technique also permit use on smaller or more delicate ligaments and retinacula with minimal damage to adjacent structures. This procedure provides a less invasive alternative to open surgical approaches and involves inexpensive equipment. Furthermore the technique requires only a matter of a few minutes. The procedure can potentially be performed in the outpatient setting with local or regional anaesthesia. The potential benefits in terms of minimisation of morbidity and cost are self evident.

EXAMPLE 3 - Psoas muscle tenotomy

[00158] A psoas muscle tenotomy was conducted using the device for a patient with psoas impingement after a hip replacement.

[00159] Psoas impingment is a painful, mobility restricting condition which may occur following total hip replacement. An open surgical approach to releasing the psoas tendon is a significant operation involving dissection to the psoas insertion onto the proximal femur. The procedure comes with risk of injury to the femoral neurovascular bundle. As an alternative to this approach, the previously described needle tenotomy device was introduced under ultrasound guidance to the psoas insertion and used to divide the psoas tendon. With the stylet tip flush with the needle cannula bevel, the device was placed adjacent the psoas insertion onto the femur. The stylet was then rotated 180degrees and fixed in the cutting position as previously described. With the hip in a degree of extension (to place some tension on the psoas tendon) the cutting tip was agitated through the tendon resulting in division. This approach obviated the need for extensive dissection and ultrasound vision of neurovascular structures minimised risk of neurovascular injury. The procedure was performed under general anaesthesia given that even with copious local anaesthetic this was likely to be moderately painful. The procedure was very successful, at 9 weeks post procedure the patient had satisfactory mobility and was pain free.

[00160] As used herein, the singular forms "a," "an," and "the" may refer to plural articles unless specifically stated otherwise.

[00161] Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. Where a specific range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is included therein. All smaller sub ranges are also included. The upper and lower limits of these smaller ranges are also included therein, subject to any specifically excluded limit in the stated range.

[00162] The term "about" or "approximately" means an acceptable error for a particular value, which depends in part on how the value is measured or determined. In certain embodiments, "about" can mean 1 or more standard deviations. When the antecedent term "about" is applied to a recited range or value it denotes an approximation within the deviation in the range or value known or expected in the art from the measurements method. For removal of doubt, it shall be understood that any range stated herein that does not specifically recite the term "about" before the range or before any value within the stated range inherently includes such term to encompass the approximation within the deviation noted above.

[00163] Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or integer or group of elements or integers but not the exclusion of any other element or integer or group of elements or integers.

[00164] Also, it must be noted that, as used herein, the singular forms "a", "an" and "the" include plural aspects unless the context already dictates otherwise.

[00165] The subject headings used herein are included only for the ease of reference of the reader and should not be used to limit the subject matter found throughout the disclosure or the claims. The subject headings should not be used in construing the scope of the claims or the claim limitations.

[00166] Reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in any country. [00167] All methods described herein can be performed in any suitable order unless indicated otherwise herein or clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the example embodiments and does not pose a limitation on the scope of the claimed invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential.

[00168] The description provided herein is in relation to several embodiments which may share common characteristics and features. It is to be understood that one or more features of one embodiment may be combinable with one or more features of the other embodiments. In addition, a single feature or combination of features of the embodiments may constitute additional embodiments.

[00169] Although the present disclosure has been described with reference to particular examples, it will be appreciated by those skilled in the art that the disclosure may be embodied in many other forms.

[00170] Future patent applications may be filed on the basis of the present application, for example by claiming priority from the present application, by claiming a divisional status and/or by claiming a continuation status. It is to be understood that the following claims are provided by way of example only, and are not intended to limit the scope of what may be claimed in any such future application. Nor should the claims be considered to limit the understanding of (or exclude other understandings of) the present disclosure. Features may be added to or omitted from the example claims at a later date.

Claims

1. A surgical cutting device, the device comprising:

2. The surgical cutting device according to claim 1, wherein the stylet comprises a projection receivable by the body to locate the stylet in the first or the second position.

3. The surgical cutting device according to claim 2, wherein the stylet comprises a body for holding the stylet and the projection projects from the body.

4. The surgical cutting device according to claims 2 or 3, wherein the projection comprises a finger.

5. The surgical cutting device according to any one of claims 2 to 4, wherein the projection projects in a direction substantially parallel to the stylet.

6. The surgical cutting device according to any one of claims 2 to 5, wherein the means for positioning the stylet comprises a recess configured to receive the projection.

7. The surgical cutting device according to claim 6, wherein the recess comprises a notch.

8. The surgical cutting device according to claims 6 or 7, wherein the recess holds the projection.

9. The surgical cutting device according to any one of claims 1 to 8, wherein the body for holding the cannula comprises a base and the means for positioning the stylet are located at the base of the body.

10. The surgical cutting device according to claim 1, wherein the means for positioning the stylet received in the cannula in a first position and in a second opposed position comprises a projection.

11. The surgical cutting device according to claim 10, wherein the stylet comprises a body and the body of the stylet comprises two opposed recesses configured to receive the projection.

12. The surgical cutting device according to any one of claims 1 to 11, wherein the body for holding the cannula is adapted to internally receive the stylet.

13. The surgical cutting device according to any one of claims 1 to 12, wherein the one or more cutting edges of the angled tip of the cannula comprise sharpened edges of a bevel of the angled tip.

14. The surgical cutting device according to any one of claims 1 to 13, wherein the angled tip of the cannula comprises a 20° - 50° bevel.

15. The surgical cutting device according to any one of claims 1 to 14, wherein the one or more cutting edges of the angled tip of the cannula comprise sharpened edges of a bevel of the angled tip.

16. The surgical cutting device according to any one of claims 1 to 15, wherein the angled tip of the stylet comprises a bevel angle substantially the same as the angle of the bevel of the cannula.

17. The surgical cutting device according to any one of claims 1 to 16, wherein the cannula is a rigid cannula.

18. The surgical cutting device according to any one of claims 1 to 17, wherein the cannula and the stylet are composed of a non- ferromagnetic metal and/or metal alloy.

19. A surgical cutting device, the device comprising:

a body for holding the cannula;

20. A surgical method of cutting a structure, the method comprising using a surgical cutting device as described according to any one of claims 1 to 19 to cut the structure.

21. The surgical method according to claim 20, wherein the method further comprises ultrasound guidance of the device to a position for cutting.

22. The surgical method according to claims 19 or 20, wherein the method is used to cut a tendon or a ligament.

23. A surgical cutting method of cutting a structure, the method comprising:

inserting into a subject a surgical cutting device according to any one of claims 1 to 19 to a desired site of cutting of a structure, wherein the stylet is located in the first position; repositioning the stylet from the first position to the second position; and cutting the structure with the surgical cutting device.

24. The surgical cutting method according to claim 23, wherein the method further comprises ultrasound guidance of the device to the desired site of cutting.

25. The surgical cutting method according to claims 23 or 24, wherein the structure comprises a tendon or a ligament.

25. A cannula for receiving a stylet, the cannula comprising:

26. A cannula for receiving a stylet, the cannula comprising:

(ii) a body for holding the cannula, wherein the body comprises a first notch and a second opposed notch, the first notch positioned so that when a projection on a stylet is received in the first notch an angled distal tip of the stylet is colocated with the angled cutting tip of the cannula and when the projection on a stylet is received in the second notch the angled distal tip of the stylet is located opposed to the angled tip of the cannula.

27. A cannula for receiving a stylet, the cannula comprising:

(i) an angled tip at a distal end, wherein the angled tip comprises an open face and the angled tip comprises one or more cutting edges; and (ii) a body for holding the cannula comprising a first notch and an opposed second notch, wherein the first notch is positioned on the body on a cylindrical polar axis of the cannula substantially perpendicularly to the open face of the angled tip.

28. A product comprising:

(i) a cannula according to claim 25; and

(ii) a stylet receivable into the cannula, the stylet comprising an angled cutting tip and means for locating the stylet in a first position or a second position.

29. A product comprising:

(i) a cannula according to claims 26 or 27; and

(ii) a stylet receivable into the cannula, the stylet comprising an angled cutting tip and a projection receivable by the notches on the body of the cannula.

30. A method of forming a surgical cutting device from a biopsy needle comprising a cannula and a stylet, the method comprising: