Percutaneous surgical device

Abstract

A percutaneous surgical device body 12 suitable for receiving a blunt tipped needle 14, 16 with an axially extended cutting edge 18, the body comprising a needle receiver 26, a sensor 20 to collect cu

Description

The present invention relates to a percutaneous surgical device, and in particular a device for carrying out percutaneous release procedures, such as trigger finger release procedures. The invention further relates to methods for carrying out percutaneous surgery using said device, as well as to a robotic assembly for automated or semiautomated percutaneous surgery. Many common injuries and conditions affecting the internal tissues of a patient’s body are treated by open surgical procedures carried out in an operating theatre, where an incision is made in the skin to allow for operation. However, the need for an incision and the prolonged retraction of tissues involved in such procedures can often lead to long term scarring and pain, as well as increasing recovery time and the risk of infection. Percutaneous surgery is a less invasive alternative to open surgery which avoids the need for a large incision, minimising the risk of infection and accelerating recovery time. In addition, percutaneous procedures can often be performed in an outpatient setting, reducing or eliminating time spent in an operating theatre. Percutaneous surgery is therefore a desirable option for a wide range of procedures as an alternative to open surgery. For example, percutaneous surgery can find application in procedures for alleviating pain, stiffness or catching caused by inflammation of a tendon or ligament by operating on the affected tissue, referred to here generally as release surgeries. Release surgeries include tennis elbow and golfers elbow release as well as digital pulley release, including release of Dupuytren’s cord, De Quervain’s release, and in particular A1 pulley release for trigger finger syndrome. While percutaneous surgery offers some advantages over open surgery, there remains a need for further development in percutaneous surgical instruments and methods. Percutaneous surgical procedures are generally more difficult to perform than open surgery due to limited access and visibility, and such procedures are considered to have a greater risk of accidental damage to surrounding tissues than conventional open surgeries. For example, in percutaneous trigger finger release surgery, there is a risk of damaging an underlying flexor tendon, flexor tendon sheath, or nerves and vessels present in neuro-vascular bundles adjacent to the flexor tendon sheath. As such, percutaneous trigger finger release surgery is not a conventionally standard procedure. It is an object of the present invention to reduce or substantially obviate the aforementioned problems. According to a first aspect of the present invention there is provided a percutaneous surgical device comprising: a surgical device body; a needle extending from the body, the needle having a blunt tip, and a cutting edge extending along at least part of an axial extent of the needle; at least one sensor at or adjacent to the needle, the or each sensor configured to produce cutting data indicative of a force, which is preferably a resistive force, acting on the cutting edge; and a controller communicated with the or each sensor for receiving cutting data therefrom, the controller being configured to identify, based on the cutting data, whether a tissue is being cut by the cutting edge. The device of the present invention provides several advantages over known tools for carrying out percutaneous release surgery. The sensors and controller of the present invention allow for accurate detection of cutting of tissue, rather than relying on solely tactile feedback as is typical in the art. This allows for procedures to be carried out more precisely and mitigates the risk of damage to surrounding tissue. The unique design of the needle further helps to prevent inadvertent damage to underlying tissue due to its blunt tip, while still allowing for effective operation with the cutting edge along an axial extent of the needle. The term blunt tip, as used throughout, should be understood to mean a substantially smooth, flat or rounded tip lacking cutting edges, rather than a sharp tip which has been dulled through use. The term resistive force, as used throughout, includes but is not limited to forces required to deform or cut the tissue by the needle and friction along a shaft of the needle, and can generally be taken to include a total force acting in opposition to the motion of the needle. Optionally, the controller is configured to identify if the targeted tissue is being cut using time-series analysis. Additionally, or alternatively, the controller may be configured to identify if the targeted tissue is being cut using machine learning. While an individual measurement of force can be useful in distinguishing between tissue being cut, variation in tissue between patients means that individual measurements indicative of force are typically not a wholly reliable indicator. Metaplasia can also lead to a hardening of the targeted tissue, exacerbating the issue of relying on individual readings. To circumvent the above issues, time-series analysis and / or machine learning techniques can be applied to readings indicative of force, such as strain readings, captured by the sensors over time to identify if signal characteristics common to cutting a targeted tissue are present in the cutting data. In one preferable embodiment, the controller is configured to detect a sinusoidal signal characteristic in the cutting data indicative of the tissue being a fibrous connective tissue. Optionally, the controller may be configured to detect sinusoidal signal characteristic indicative of the tissue being an A1 pulley. Fibrous connective tissue such as tendons and ligaments have a structure comprising bundles of fibres. It has been found that fibrous connective tissue, such as the A1 pulley located in a hand of a patient, produce a distinctive sinusoidal signal characteristic when being cut. This signal characteristic can be detected in the cutting data to accurately determine when fibrous connective tissue is being cut. In one optional embodiment, the, each, or a further sensor is configured to produce penetration data indicative of an axial force acting on the tip or cutting edge of the needle. Advantageously, the controller may be configured to identify, based on a change in the axial force of the penetration data, when the tip or cutting edge of the needle encounters a tissue boundary between two differing tissues having differing mechanical properties. Penetrative data indicative of an axial force acting axially on the tip or cutting edge of the needle can be utilised to determine when the needle has been inserted far enough into a patient to reach a targeted tissue to be cut. It is particularly useful to identify when the needle encounters boundaries between tissues, as this can provide information to the surgeon on the location of the needle within the patient. This allows accurate determination of when the needle reaches a specific targeted tissue to be cut and mitigates the risk of inserting the needle past the targeted tissue and damaging underlying tissue. Preferably, the percutaneous surgical device further comprises an indicator communicated with the controller and configured to receive an instruction from the controller to produce an indication when the controller identifies, based on the cutting data, that the tissue has been cut by the cutting edge. Optionally, the indicator comprises at least one light emitting device at or adjacent to the surgical device body. An indicator can provide audible, visual or haptic indication to a surgeon to indicate when tissue is being or has been cut by the cutting edge. The indicator gives the surgeon a clear indication as to the stage of the operation and allows the surgeon to stop cutting in a direction as soon as the indication is received, preventing cutting of surrounding tissue while also ensuring that the tissue is fully severed. This is of particular importance for percutaneous surgery as visibility is greatly limited. Preferably, the needle has two cutting edges disposed at either side of the needle. Two cutting edges allow for the device to be used to cut bidirectionally. A beneficial method of operation involves the needle of the percutaneous surgical device being inserted close to the centre of the tissue to be then cut in two opposing directions using the two cutting edges of the needle to completely cut the tissue. Inserting the needle closer to the centre of the tissue mitigates the risk of damage to surrounding tissue compared to inserting the needle to adjacent to the tissue. Preferably, the needle includes a bevelled portion adjacent to the tip, the bevelled portion defining the or each cutting edge of the needle. More preferably, the bevelled portion includes a first bevel and two second bevels symmetrically disposed at opposing sides of the first bevel, each second bevel defining an opposing cutting edge of the needle. A bevelled portion allows for the needle to cut through the tissue of a patient more smoothly, causing less pain and discomfort to the patient. Advantageously, the needle may be a cannulated needle. In other words, the needle may comprise a central bore extending through at least part of the axial extent of the needle. A cannulated needle with a bore extending therethrough can pass more easily through tissue and skin, reducing pain to the patient. By providing a central bore, the walls of the needle, which define the cutting edge, are thin and can act as a knife edge. Additionally, a cannulated needle allows for medicine or drugs to be injected into the patient through the bore of the needle during or after the procedure. Preferably, the needle is releasably engageable with the surgical device body. The needle of the percutaneous surgical device needs to be both sharp and sterile for operation. It is thus beneficial that the needle be releasably engageable, so as to allow for the needle to be easily replaced after operation, without needing to replace the other components of the percutaneous surgical device. Optionally, said at least one sensor comprises a strain gauge. Preferably, there are at least two sensors opposingly arranged relative to the needle. Strain gauges are relatively cheap sensors which can measure strain to high precision, which makes them an excellent choice to generate cutting data indicative of the force acting on the needle. Positioning the sensors at opposing sides of the needle allows for the forces acting on either side of the needle to be measured. Optionally, the surgical device body includes a handle portion for allowing manipulation of the device by a surgeon. According to a second aspect of the present invention, there is provided a method of percutaneous trigger finger release surgery, the method comprising the steps of: i) providing a percutaneous surgery device according to the first aspect of the invention; ii) inserting the needle of the device through a percutaneous entry point into a body of a patient; iii) cutting a biological tissue with the cutting edge; and iv) a controller of the percutaneous surgical device identifying when the cutting of step iii) is complete, based on cutting data received from a sensor of the percutaneous surgical device. Optionally, the method of percutaneous surgery may further comprise the step of v) indicating via the indicator that the cutting of step iii) is complete. Optionally, the biological tissue may be an A1 pulley of a hand. According to a third aspect of the invention, there is provided a robotic assembly for automated or semi-automated percutaneous surgery, the robotic assembly comprising: a percutaneous surgical device according to the first aspect of the invention; and at least one actuator communicated with the controller of said percutaneous surgical device, the or each actuator being configured to move the percutaneous surgical device and configured to receive an instruction from the controller to maintain or terminate movement of the percutaneous surgical device based on an identification made with regards to the cutting data as to whether the tissue is being cut. According to a fourth aspect of the invention, there is provided a percutaneous surgical device body for receiving a needle having a blunt tip and a cutting edge along at least part of an axial extent of the needle, the body comprising: a needle receiver for receiving the needle; at least one sensor at or adjacent to the needle, the or each sensor configured to produce cutting data indicative of a force acting on the cutting edge; and a controller communicated with the or each sensor for receiving cutting data therefrom, the controller being configured to identify, based on the cutting data, whether a tissue is being cut by the cutting edge. According to a fifth aspect of the invention, there is provided a needle for the surgical device body of the fourth aspect of the invention, the needle comprising a blunt tip and a cutting edge along at least part of an axial extent of the needle. For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made by way of example only to the accompanying drawings, in which: Figure 1 shows a schematic view of a first embodiment of a percutaneous surgical device in accordance with the first aspect of the invention; Figure 2 shows a partially exploded view of the percutaneous surgical device of Figure 1; Figure 3 shows a partial front perspective view of the percutaneous surgical device of Figure 1; Figure 4 shows an enlarged perspective view of the tip of a needle of the percutaneous surgical device of Figure 1; Figure 5 shows a side perspective view of the needle of Figure 4; Figures 6 and 7 show exemplary cutting data produced by at least one sensor of the percutaneous surgical device of Figure 1 during cutting of an A1 pulley of a hand of a patient; Figure 8 shows a perspective view of the hand of the patient showing biological tissue to be operated on using the percutaneous surgical device of Figure 1; Figure 9 shows an illustration of a procedure for cutting the A1 pulley of the hand of the patient using the needle of the percutaneous surgical device of Figure 1; and Figure 10 shows a schematic view of a first embodiment of a robotic assembly for automated or semi-automated percutaneous surgery in accordance with the third aspect of the invention. Referring firstly to Figures 1 and 2, there is shown a first embodiment of a percutaneous surgical device 10. The percutaneous surgical device 10 includes a surgical device body 12 and a needle 14 extending from the body 12. The needle 14 has a blunt tip 16 and a cutting edge 18 extending along part of an axial extent of the needle 14. The percutaneous surgical device 10 further includes two sensors 20 adjacent to the needle 14 for producing cutting data indicative of a force, which is preferably a resistive force, acting on the cutting edge 18 of the needle 14 in use and a controller 22 communicated with each sensor 20. The surgical device body 12 of the percutaneous surgical device 10 includes a handle portion 24, a needle receiver 26, and a sensor mounting portion 28. The handle portion 24 is positioned at a rearward or proximal end of the percutaneous surgical device 10 and functions as a grip fora surgeon using said device. The handle portion 24 is sized to be holdable by a user with a pen-like grip, allowing for handling and manipulation of the percutaneous surgical device 10 to perform surgery. The needle receiver 26 is located at a forward end of the percutaneous surgical device 10, meaning an end of the percutaneous surgical device 10 which is directed towards a patient during a surgical procedure. The needle 14 is releasably engageable with the needle receiver 26, allowing for the needle 14 to be easily replaced after operation with a fresh, sterile needle. This may be accomplished by any suitable means such as a locking pin, catch or clamp, or by a bayonet fitting or screw thread engagement. The sensor mounting portion 28 interconnects the handle portion 24 and the needle receiver 26 and is positioned adjacent to needle receiver 26, where an in-use measurement indicative of the force on the cutting edge 18 is greater due to being adjacent to the needle 14. The sensor mounting portion 28 may include two bridges 30 defining an internal void 31 therebetween, with each bridge 30 having a slot 33 to receive a sensor. The bridges 30 may be thin so as to elastically deform for a maximum measurement of strain when the percutaneous surgical device 10 is in use and forces act on the cutting edge 18 of the needle 14. Alternatively, a solid construction of the sensor mounting portion without the internal void space may be used, especially if the sensors do not rely on a measured strain. This may be the case if, for example, pressure sensors are used. As the needle 14 is disposable and intended to be replaced, it is preferred that the or each sensor 20 is located on the surgical device body 12. However, the percutaneous surgical device can function equally effectively in embodiments of the invention where the or each sensor is located on the needle. In such embodiments, the sensor mounting portion of the percutaneous surgical device may be excluded. The needle may not necessarily be disposable, and may be reusable with suitable cleaning procedures. The needle 14 of the percutaneous surgical device 10 is described with reference to Figures 4 and 5. Unlike conventional hypodermic needles commonly used for percutaneous surgery, the needle 14 of the percutaneous surgical device 10 has a blunt tip 16 with a rounded or smooth point. This is to inhibit damage to underlying tissue during operation, which is a common problem with typical needles used in the art. The needle 14 has two cutting edges 18 each extending along at least part of an axial extent of the needle 14. In other words, the cutting edges 18 are at the sides of the needle 14. The cutting edges 18 do not extend to the tip 16 of the needle 14 and instead are adjacent to the blunt tip 16. The cutting edges 18 are arranged on opposite sides of the needle 14, so that the needle 14 can be used to cut bidirectionally without requiring reorientation. While an arrangement with two cutting edges 18 is preferred to allow for cutting in two different directions, the needle could function effectively with only a single cutting edge, or may even be provided with more than two cutting edges. Preferably, the cutting edges 18 extend along only a part of the axial extent of the needle to allow for greater precision when cutting. For example, the cutting edges 18 are confined to a tip-adjacent portion of the needle. As such, the cutting edges 18 extend along less than half of the axial extent of the needle 14, and more preferably less than a tenth of the axial extent of the needle 14. The needle 14 includes a bevelled portion 32 adjacent to the blunt tip 16 having a first bevel 34. The needle further includes two second bevels 36, with the two second bevels 36 being symmetrically disposed and each defining an opposing cutting edge 18. It is however possible for the first bevel to be omitted, with the two second bevels being contiguous with each other, for example. The needle 14 is preferably cannulated, or in other words the needle 14 comprises a bore 38 through its axial extent. This can allow for substances such as drugs or medication to be injected through the bore 38 of the needle into a patient. For example, the cannulated needle 14 may be used to inject local anaesthetic during the procedure to reduce the pain of the operation. Alternatively, or additionally, the cannulated needle 14 may be used to inject a steroid or other anti-inflammatory medication after cutting is completed. Botox may also be injected via the cannulated needle 14 to relax contracted muscles to treat spasticity. Drugs or medication may be injected directly through the bore 38 of the needle, or alternatively a tube may be inserted through the bore 38. The tube can then for example be connected to a syringe with a plunger for the administration of the medication or drug. In other envisioned embodiments, the surgical device body may comprise one or more containers (not shown) in fluid communication with the bore of the needle for holding medication, drugs or other fluids such as saline. The or each container may include an actuator for moving the fluid from the container to the bore. For example, the or each container may be sealed at or adjacent a surface of the surgical device body by a removably engageable plunger, which allows for the surgeon to administer the drugs or medication in one of the containers by operating the corresponding plunger. Alternatively, the percutaneous surgical device may include one or more pumps or mechanically actuatable plungers in communication with the controller of the percutaneous surgical device, which may be configured to pump drugs or medication from the containers upon receiving an instruction from the controller. The pumps or mechanically actuatable plungers may be connected to one or more buttons or switches positioned on an outer surface of the surgical device body to allow a user to operate the pumps or plungers. While a cannulated needle is preferred, the percutaneous surgical device can also operate with a solid needle. The bevelled portion 32 and / or bore 38 improve the passage of the needle 14 through tissue, and allow for a sharp cutting edge 18 to be formed on the second bevels 36 for cutting through tissue. The needle has the general shape of a needle, which is to say that it is elongate and fine, with a generally cylindrical shaft. The needle 14 preferably has a needle gauge of between 15 and 25, and most preferably has a needle gauge of 20. The sensors 20 of the percutaneous surgical device 10 are configured to produce cutting data indicative of the force, such as the resistive or reaction force, acting on the cutting edge 18 of the needle 14 when the needle 14 is cutting tissue. The sensors 20 comprise two strain gauges 40 opposingly arranged relative to the needle 14, with each strain gauge 40 being mounted on a respective bridge 30 of the sensor mounting portion 28. This allows for accurate measurement of strain on both of the opposing cutting edges 18 of the needle 14. The sensors 20 may be further configured to produce penetration data indicative of a axial force, which may also be a resistive or reaction force, acting axially on the tip 16 or cutting edges 18 of the needle 14. Additionally, or alternatively, one or more further sensors may be provided to produce this penetration data, which may be located on the sensor mounting portion or directly on the needle. Exemplary cutting data taken from trial measurements is shown in Figures 6 and 7. The cutting data, which may comprise strain or a derivative of strain and is indicated on the Y axis, was obtained using a needle as described above over a period of time indicated on the X axis, with two strain gauges configured as earlier described. Time periods T1, T2 represent times where tissue, in this case the A1 pulley, was being cut by the cutting edge 18 of the needle 14. A sinusoidal signal characteristic can be seen in the cutting data while the A1 pulley was being cut, caused by the severing of fibre bundles in the fibrous connective tissue. Sinusoidal signal characteristic should be understood to mean resembling a sinusoid, particularly with regards to the data having many alternating peaks and troughs. It should be understood that the cutting data does not necessarily have the form of an exact sinusoid. This cutting data and / or penetration data is communicated from the sensors 20 to the controller 22, which may be provided as a processor of a printed circuit board. The cutting and / or penetration data may be communicated by wires to the controller 22 and may be stored in a memory of the controller 22. The sensors 20 may instead be communicated with the controller 22 wirelessly, for example via a Bluetooth (RTM) connection. The controller 22 includes a data and power connection 42, supplying power to the device 10 and allowing for cutting data obtained through the sensors 20 to be transferred externally. This allows for, for example, the cutting data to be processed externally by an external processor. The controller 22 continually receives cutting data from the sensors 20 while tissue is being cut by the cutting edge 18. The controller 22 is configured to identify, based on this cutting data, whether a tissue is being cut. This may be done in part by comparison of a detected strain and a known strain value for cutting a particular tissue. However, variation in tissue between patients and metaplasia of tissue make it difficult to use individual strain readings to distinguish tissue. In order to identify if a tissue is being cut, time-series analysis techniques can be applied to strain readings captured by the sensors 20 over time to identify if signal characteristics common to cutting a targeted tissue are present in the cutting data. Alternatively, or additionally, machine learning techniques may be used to identify signal characteristics in the cutting data. The aforementioned time-series analysis techniques and machine learning techniques may also be used to analyse penetration data to identify where the tip 16 of the needle 14 encounters a tissue boundary between two differing tissues having differing mechanical properties, which may be identified by a sudden drop or jump in the force acting on the tip 16 of the needle 14. In case of the examples of Figures 6 and 7, a sinusoidal signal characteristic can be seen, generally representative of cutting fibrous connective tissue and in this case specifically representative of the A1 pulley. The controller 22 can analyse the received cutting data and penetration data in real time to search for and identify the sinusoidal signal characteristic, allowing for detection that the tissue is being cut. The percutaneous surgical device 10 further includes an indicator 44 which is communicated with the controller 22 by a wired connection. Again, alternative means of communicating the controller 22 and indicator 44 may be considered, including a wireless connection. The indicator 44 includes two light emitting devices 46 positioned at an outer surface of the surgical device body 12. The light emitting devices 46 are configured to provide an indication to the user after receiving an instruction from the controller 22. A preferred configuration has one light emitting device 46 configured to produce a continual indication when the device 10 is receiving power and data through a power and data connection 42 and one light emitting device 46 configured to produce an indication upon an instruction from the controller 22 when the tissue has been cut. Preferably, the light emitting devices 46 will emit light of different colours to allow the user to more easily distinguish between the different indications. Other numbers and arrangements of light emitting devices 46 may be considered. The indicator 44 may alternatively, or additionally, comprise at least one of a speaker for producing an audible indication based on an instruction from the controller 22 and / or a vibrator for producing a haptic indication based on an instruction from the controller 22. A method of percutaneous surgery, which is a trigger finger release procedure, using the percutaneous surgical device 10 is illustrated in Figures 8 and 9. Figure 8 shows a hand 48 of a patient with the landmark location of the A1 pulley 50 shown, along with the position of the A2 pulley 52 and underlying flexor tendons 54. Before the procedure, local anaesthetic may first be injected into the hand of the patient. In operation, a percutaneous entry point is made into the body of a patient with either the needle 14 of the percutaneous surgical device 10 or with a separate needle having a sharp tip. The needle 14 of the device 10 is then inserted through the percutaneous entry point and into the centre of the tissue to be cut, here being the A1 pulley 50, with the or each sensor 20 producing penetration data indictive of the force acting axially on the tip 16 of the needle 14. Alternatively, before the needle 14 is inserted, a dilator may first be inserted. In use, the penetration data is continuously received by the controller 22 as the needle 14 passes through the tissue. The controller 22 identifies, based on the penetration data, where the tip 16 of the needle 14 encounters a tissue boundary between two differing tissues having differing mechanical properties, and may indicate this to the user via the indicator 44 of the percutaneous surgical device 10. As such, the surgeon is informed and avoids further insertion of the needle 14. In the case of the trigger finger release procedure, there is a change in resistance as the needle tip 16 leaves the pulley 50 and enters the space between the hard pulley 50 and gliding layer of the of the tendon 54. If inserted further, it reaches the tendon 54 which will be detected by another change in resistance. The tissue can then be cut by the cutting edge 18 of the needle 14 in a proximal and distal direction. In the case of the A1 pulley 50, the A1 pulley is divided through the cutting action. During cutting of the tissue, the or each sensor 20 continually produces cutting data which is communicated to the controller 22. The controller 22 then identifies when the cutting of the tissue is complete based on the cutting data received from the or each sensor 20, as outlined above. The indicator 44 will then provide an indication accordingly, and the surgeon stops the cutting action. Referring now to Figure 10, a robotic assembly 156 for automated or semi-automated percutaneous surgery in accordance with the third aspect of the invention is shown. Identical or similar reference numerals will be used to refer to identical or similar components, and further detailed description is omitted for brevity. The robotic assembly 156 includes a percutaneous surgical device 110 as described in detail above. However, the needle 114 of the percutaneous surgical device 110 extends orthogonally to an axis of the surgical device body 112 rather than projecting from an end. In alternative embodiments, the needle 114 may project from the distal end of the surgical device body 112, as described for the first aspect of the invention. The percutaneous surgical device 110 is coupled to two linear actuators 158 for movement in two different directions. In principle, a greater or fewer number of actuators 158 may be provided depending on the complexity of the operation. For example, the percutaneous surgical device may be mounted to a six-axis robotic arm. As the percutaneous surgical device 110 is manipulated by actuators 158, the surgical device body 112 does not include a handle portion. The linear actuators 158 are communicated with the controller (not shown) of said percutaneous surgical device 110 by a wired connection. As before, the connection may instead be a wireless connection. The linear actuators 158 are configured to receive an instruction from the controller to maintain or terminate movement of the percutaneous surgical device 110. This occurs based on an identification made with regards to the cutting data provided from sensors 120 as to whether the tissue is being cut, which allows for an operation to be carried out automatically or semi-automatically. While strain gauges are a preferred choice for the or each sensor of the percutaneous surgical device, any sensor capable of capturing a measurement indicative of a force, and in particular a resistive force, on the needle may be considered. The at least one sensor may include any one or combination of resistive and piezoresistive force sensors, piezoelectric force sensors, capacitive force sensors, optical force sensors and pressure sensors. It is to be understood that this list is not exhaustive. While the sensors are provided on the surgical device body in the illustrated embodiment, it is equally feasible that the or each sensor is disposed on the shaft and / or the tip of the needle. It is also feasible that both the sensor mounting portion of the surgical device body and the needle may each include at least one sensor. In summary, the present invention provides a percutaneous surgical device which allows for the accurate detection of cutting of tissue, allowing for procedures to be carried out more efficiently and with less risk of damage to surrounding tissue. The words ‘comprises / comprising’ and the words ‘having / including’ when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps, or components, but do not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. The embodiments described above are provided by way of example only, and various changes and modifications will be apparent to persons skilled in the art without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A percutaneous surgical device comprising:a surgical device body;a needle extending from the body, the needle having a blunt tip, and a cutting edge extending along at least part of an axial extent of the needle;at least one sensor at or adjacent to the needle, the or each sensor configured to produce cutting data indicative of a force acting on the cutting edge; anda controller communicated with the or each sensor for receiving cutting data therefrom, the controller being configured to identify, based on the cutting data, whether a tissue is being cut by the cutting edge.

2. A percutaneous surgical device as claimed in claim 1, wherein the controller is configured to identify if the tissue is being cut using time-series analysis.

3. A percutaneous surgical device as claimed in claim 1 or claim 2, wherein the controller is configured to identify if the tissue is being cut using machine learning.

4. A percutaneous surgical device as claimed in any one of the preceding claims, wherein the controller is configured to detect a sinusoidal signal characteristic in the cutting data indicative of the tissue being a fibrous connective tissue.

5. A percutaneous surgical device as claimed claim 4, wherein the sinusoidal signal characteristic is indicative of the tissue being an A1 pulley.

6. A percutaneous surgical device as claimed in any one of the preceding claims, wherein the, each, or a further sensor is configured to produce penetration data indicative of an axial force acting on the tip or cutting edge of the needle.

7. A percutaneous surgical device as claimed in claim 6, wherein the controller is further configured to identify, based on a change in the axial force of the penetration data, when the tip or cutting edge of the needle encounters a tissue boundary between two differing tissues having differing mechanical properties.

8. A percutaneous surgical device as claimed in any one of the preceding claims, further comprising an indicator communicated with the controller and configured to receive an instruction from the controller to produce an indication when the controller identifies, based on the cutting data, that the tissue has been cut by the cutting edge.

9. A percutaneous surgical device as claimed in claim 8, wherein the indicator comprises at least one light emitting device at or adjacent to the surgical device body.

10. A percutaneous surgical device as claimed in any one of the preceding claims, wherein the needle has two cutting edges disposed at either side of the needle.

11. A percutaneous surgical device as claimed in any one of the preceding claims, wherein the needle includes a bevelled portion adjacent to the tip, the bevelled portion defining the or each cutting edge of the needle.

12. A percutaneous surgical device as claimed in claim 11, wherein the bevelled portion includes a first bevel and two second bevels symmetrically disposed at opposing sides of the first bevel, each second bevel defining an opposing cutting edge of the needle.

13. A percutaneous surgical device as claimed in any one of the preceding claims, wherein the needle is a cannulated needle.

14. A percutaneous surgical device as claimed in any one of the preceding claims, wherein the needle is releasably engageable with the surgical device body.

15. A percutaneous surgical device as claimed in any one of the preceding claims, wherein said at least one sensor comprises a strain gauge.

16. A percutaneous surgical device as claimed in any one of the preceding claims, wherein there are at least two sensors opposingly arranged relative to the needle.

17. A percutaneous surgical device as claimed in any one of the preceding claims, wherein the surgical device body includes a handle portion for allowing manipulation of the device by a surgeon.

18. A method of percutaneous surgery, the method comprising the steps of:i) providing a percutaneous surgical device as claimed in any one of the preceding claims;ii) inserting the needle of the device through a percutaneous entry point into a body of a patient;iii) cutting a biological tissue with the cutting edge; andiv) a controller of the percutaneous surgical device identifying when the cutting of step iii) is complete, based on cutting data received from a sensor of the percutaneous surgical device.

19. A method of percutaneous surgery as claimed in claim 18 wherein the surgical device is according to claim 8, further comprising the step of v) indicating via the indicator that the cutting of step iii) is complete.

20. A method of percutaneous surgery as claimed in claim 18 or claim 19, wherein the biological tissue is an A1 pulley of a hand.

21. A robotic assembly for automated or semi-automated percutaneous surgery, the robotic assembly comprising:a percutaneous surgical device as claimed in claims 1 to 17; andat least one actuator communicated with the controller of said percutaneous surgical device, the or each actuator being configured to move the percutaneous surgical device and configured to receive an instruction from the controller to maintain or terminate movement of the percutaneous surgical device based on an identification made with regards to the cutting data as to whether the tissue is being cut.

22. A percutaneous surgical device body for receiving a needle having a blunt tip and a cutting edge along at least part of an axial extent of the needle, the body comprising:a needle receiver for receiving the needle;at least one sensor at or adjacent to the needle, the or each sensor configured to produce cutting data indicative of a force acting on the cutting edge; anda controller communicated with the or each sensor for receiving cutting data therefrom, the controller being configured to identify, based on the cutting data, whether a tissue is being cut by the cutting edge.

23. A needle for the surgical device body of claim 22, the needle comprising a5 blunt tip and a cutting edge along at least part of an axial extent of the needle.19

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