A method and apparatus for testing a surgical tool and a method and apparatus for replicating ocular surfaces

Abstract

A method and apparatus 10 for testing a surgical tool 12 comprising: providing a testing sample 20, an instrument manipulator 18 for controlling the tool, and a sensor 24 for measuring a force applied

Description

04 04 25 The present invention relates to a method and apparatus for 5 testing a surgical tool and a method and apparatus for replicating ocular surfaces and relates particularly, but not exclusively, to testing forceps for intra-ocular surgery. Across the medical industry there are numerous manufacturers and designers of surgical tools such as forceps, 10 scalpels, and needles. Objectively comparing the differences between the same instruments from various manufactures can sometimes be difficult as the same user is not able to test multiple instruments on the same tissue of the same patient to understand the subtle differences among different makes and 15 provide reliable comparative data. Instead, instruments evaluations are usually done by giving away free sample to different surgeons, while this kind of evaluation is helpful, it is not accurate and subject to bias of the user and the differences between samples being used. 20 Furthermore, some instrument designs are meant to be safer or meant to be used in a way different from others, or example a forceps could be designed to be more effective than others when applied on a tissue at an oblique angle or in pulling the tissues in certain angles. Demonstrating these subtle 25 differences in an objective is currently very challenging. Therefore, some companies may use incentives to encourage medical professionals to choose their instruments over the competitors' . These incentives are generally not scientific and do not include objective testing the instruments to check for 30 performance issues or design assessments. An example of having multiple instrument choice for a specific surgery is the wide array of forceps available for 04 04 25 ophthalmic operations. Denting, pinching and peeling are techniques used by forceps in such surgeries to peel an epiretinal membranes, internal limiting membranes, proliferative fibroglial or fibrovascular membranes. Each of these tissues could require slightly different forceps design to perform the task effectively. For example, some instruments are designed to be sharper whilst others are deigned to generate more friction with the tissues. However, these different properties cannot be fully understood or tested to check for effectiveness, accuracy or functionality. Currently, objectively determine the performance and properties of newly manufactured forceps before using them in surgery is challenging. Preferred embodiments of the present invention seek to overcome or alleviate the above-described disadvantages of the prior art. According to an aspect of the present invention there is provided a method for testing forceps, comprising: providing at least one testing sample comprising at least one resiliently deformable material having a surface and at least one membrane portion adhered to said surface of said material; adjusting the strength of said adhesion; adjusting the strength of said adhesion; providing at least one instrument manipulator for controlling 30 the forceps comprises at and wherein instrument manipulator further least one first motor for moving said forceps towards and away from said testing sample and at least one second motor for opening and closing said forceps; providing at least one for measuring a force on the testing sample applied by the forceps; using the instrument on the testing sample; and receiving data from the sensors. By providing a testing platform to assess a surgical tool a surgeon or other medical and engineering professional can verify the functionality and practicality of the tool before 5 surgery. The data obtained also enables the surgeon to have better understanding of the properties of the instrument in use. By improving the surgeons understanding and awareness regarding the properties improves the quality and the safety of the procedure . 04 04 25 10 The testing platform also provides a quality assurance system to test and verify surgical instruments that fall into the same category. For example, being able to test a random sample from a batch of the same manufactured forceps can help give an indication of whether or not the entire batch is up to 15 standard. During this process any problems or defects in the instruments can be found and addressed quickly. The platform and specifically the data received from the platform also enables fair, accurate and detailed scientific comparison between instruments manufactured by different 0 companies and intended for the same surgical purpose. The data received from different instruments can be used to perform a side-by-side comparison. It also provides a scientific basis for which an informed decision can be made with regards to the choice of the instruments by providing reproducible results 25 data. The platform can further help demonstrate a new functional addition to a surgical tool. This can be used to verify a recent concept or theory involved in the design of an instrument. By having a platform to verify a new concept, manufacturers have 30 the ability to develop safer and more cost-effective instruments whilst also decreasing the time and expenses by testing the concept of their designs in advance. The platform also operates as a training tool for surgeons new to specific types of surgery. For example, a trainee surgeon or a newly qualified ophthalmic surgeon may not have performed surgery for removal or peeling of epiretinal membranes and 5 internal limiting membranes or may not have used a new forceps or tool recently introduced to them. By having a testing sample mimicking the properties of these membranes the new surgeon can be taught using the testing platform on how the surgery is performed without. The testing platform could also be used as 10 a platform to practice techniques such as denting, peeling and pinching. The data received could be used to compare the different techniques and also show in detail the amount of force required for each. The above described method allows an accurate reproduction of a allowing for testing of of surgical techniques. membrane of the body with adjustable adhesion force, for example, the epiretinal membranes of the eye, can be mimicked surgical instruments and the practicing In a preferred embodiment the method may further comprise ¢-^20 undertaking a simulated surgical procedure; determining whether the procedure was successfully achieved; and varying the force applied by the surgical tool repeating the procedure until successfully achieved. By having the ability to determine whether or not the 25 simulated surgical procedure is successful by varying the force applied can be helpful in teaching a new surgeon or by making direct comparisons between new surgical tools. In another preferred embodiment the method may further comprise undertaking a simulated surgical procedure by varying 30 the force applied by the surgical tool; determining whether the procedure was successfully achieved as the force varies; and 04 04 25 recording the sensor data at the point which the procedure was successfully achieved. In an alternative preferred embodiment, the method may further comprise moving the forceps in a first direction towards 5 the sample thereby applying a first force to the sample; applying a second force to the forceps thereby closing the ends of the forceps and engaging the sample; and moving the forceps in a second direction away from the sample. The method may additionally comprise measuring the first 10 force using a load cell and analysing the data by comparing between different surgical instruments used. According to a further aspect of the present invention an apparatus for testing forceps, the apparatus comprising: at least one instrument manipulator for holding and controlling 15 at least one forceps and wherein said instrument manipulator further comprises at least one first motor for moving said forceps towards and away from said testing sample and at least one second motor for opening and closing said forceps; at least one testing sample comprising at least one resiliently 20 deformable material having a surface and at least one membrane portion adhered to said surface of said material; means for adhering said membrane portion to said resiliently deformable material; and at least one sensor for measuring a force applied by the surgical 25 instrument to the forceps. In a further preferred embodiment, the sensor further comprises a plurality of sensors including a first sensor for measuring a first force applied by the surgical tool and a second sensor for measuring a second force applied to the testing 30 sample. The apparatus may further comprise means for adjusting and standardising the strength of adhesion. In a preferred embodiment the membrane portion is adhered to said surface by a vacuum or adhesive. 5 In another preferred embodiment the variation of the adhesion of said membrane portion is achieved by variation of the vacuum applied. In a preferred embodiment the testing sample further comprises an elongate sheet being provided on a first roller and 10 drawn across the resiliently deformable material onto a second roller . 04 04 25 In another preferred embodiment the resiliently deformable material further comprises a sponge material. Preferred embodiments of the present invention will now be 15 described, by way of example only, and not in any limitative sense with reference to the accompanying drawings in which:- Figure 1 is a perspective view of an apparatus of the present invention; Figure 2 is a frontal view of the apparatus of figure 1; 20 Figure 3 is a side view from the left of the apparatus of figure 1; Figure 4 is a side view from the right of the apparatus of figure 1; Figure 5 is a top view of the apparatus of figure 1; 25 Figure 6 is a rear view of the apparatus of figure 1; and Figure 7 is a schematic drawing of an eye surface replica apparatus . Referring initially to figures 1 to 6, an apparatus 10 is provided to manipulate a surgical instrument which in this 30 example is in the form of forceps 12 which have a handle 14 and a tip 16. The apparatus includes an instrument manipulator 18, a testing sample 20 and a pair of sensors 22 and 24. The instrument manipulator includes a clamp 26 and five motors in the form of motorised actuators. The first three actuators 30, 5 34 and 32 are used for moving the forceps relative to the testing sample 20. The first actuator 28 moves the forceps 12 up and down along a first axis 34 during testing, the second actuator 30 moves the forceps sideways along a second axis 36 whilst the third actuator moves the forceps back and forth along a third 10 axis 38. All three axes are perpendicular to each other. The fourth and fifth actuator's 40a and 40b are used for controlling the opening and closing mechanism of the forceps 12, the mechanism of which is located on the handles 14. Attached at one end of the first actuator 28 is a first frame 42 that surrounds a first threaded rod 44 with both the rod and the frame located along to the first axis 36. The first rod 44 is attached at one end to the inside of the first frame 42 whilst the other end is attached to the first actuator 28 allowing the actuator to rotate the rod. The combination of the first actuator 28, first rod 44 and first frame 42 form a first arm 46. Connected to one end of the second actuator 30 and located along the second axis 38 is a second frame 48 also surrounding a second threaded rod 50 and forming a second arm 52. The second 25 rod 50 is attached at one end to the inside of the second frame 48 and attached to the second actuator 30 at the other end. The third actuator 32 is further connected to a third frame 50 surrounding a third threaded rod 54. The third rod 54 being attached at one end to the third actuator 32 and attached to the 30 third frame 50 at the other end. With these three components forming a third arm 58. Also attached perpendicularly to each other are the second and third arms 52 and 58. They are attached via a second attachment 60 in the form of an L-shaped bracket whereby a third face 62 of the bracket is attached to the opposing side of the second actuator 30 of the second arm 52. With the fourth face 64 of the second attachment 60 including a second threaded 5 aperture (not shown) through which the third threaded rod 56 of the third arm 58 extends through. Further attached to the first threaded rod 44, of the first arm 46, is a fourth arm 68 by a third attachment 70. The third attachment 70 could also be in the form of an L-shaped bracket 10 including a fifth face 72 attached to the fourth arm 68 and a sixth face 74 having a third threaded aperture (not shown) for extending through the first threaded rod 44 of the first arm 46. The fourth arm includes the clamp 2 6 and the fourth and fifth actuators 40a and 40b. The fourth and fifth actuators 40a and 15 40b are located adjacent to each other attached at one side with ► । the opposing sides having a subsequent fourth and fifth frame 78a and 78b. Both the fourth and fifth frames 78a and 78b » surround a fourth and fifth threaded rod 80a and 80b, with the , each rod attached at one end to its corresponding actuator (40a ^20 and 40b) and the other end attached the corresponding frames (78a and 78b). Extending from the top of the fourth and fifth frames 78a and 78b and above the fourth and fifth actuators 40a and 40b is the clamp 26. The clamp 26 holds the top of the handle 14 of the forceps 12 such that the forceps 12 are parallel with 25 the first axis 34 of the first arm 46. Also located on the forceps 12 is a gripping portion 82. The gripping portion 82 is internally connected to the tip 16 so when the gripping portion is pressed the tip closes and when they are released the tip opens. Located either side of the gripping portion 82 is a 30 pair of forceps controllers 84a and 84b. The forceps controllers 84a and 84b include a first and a second surface 86a and 86b that can engage with the gripping portion 82 of the forceps 12. A first and second sensor 22a and 22b in the form of loads cells is further located adjacent the first and second surfaces 86a and 86b. The forceps controllers 84a and 84b are also connected to the fourth arm 68, with one of each connected to the fourth and fifth threaded rods 80a and 80b. Located below the forceps 12 running parallel to the second 5 axis 36 of the second actuator 30 is the testing sample 20. In figure 1 the sample 20 is in a position P and has a central portion 89 in the form of a thin membrane. The testing sample 20 is in a form similar to a conveyor belt 90 extending between and around pair of wheels 92. The wheels 92 have the ability 10 to rotate via actuators in the form of stepper motors (not shown) and therefore can move the testing sample 20 along the direction of the second axis 36. In figure 1 multiple sample sites 20b are located along the length of the sample belt 90. These are indicated as circles in figure 1 as a visual representation of 15 LO the different sample testing sites on the sample belt 90. CM Located directly below the testing sample 20 (when in position P) in figure 1 is a vacuum chamber 94, a third sensor 96 and a fifth arm 98. The vacuum chamber 94 (when turned on) holds the testing sample 20 securely in place whilst the third sensor 24 measures forces applied to the testing sample. The fifth arm 98 includes a sixth actuator 100, attached at one end to the third sensor 24 and a sixth frame 102 attached at the opposing end of the sixth actuator. The sixth frame 102 surrounds and secures a sixth thread rod 104, the rod being 25 attached to the sixth actuator at one end and the frame at the other end. The sixth rod 104 further extends through a fourth aperture (not shown) of a fourth attachment 106. The fourth attachment connects the vacuum chamber 94 to the fifth arm 98. Referring now to figure 7, an apparatus for replicating a 30 surface of an eye (an eye surface replica 110) includes a resiliently deformable material 112, a membrane portion 114 and a vacuum chamber 94. The resiliently deformable material 114 is in the form of a sponge. The sponge material 112 is used to 04 04 25 replicate the inside texture of an eye and therefore any material that would deform under a certain amount force and return to its original shape after the force has been released could be used. Other materials could also be used to replicated different 5 bodily tissues or fluids such as a gels or oils. The sponge material 112 is located inside the vacuum chamber 94 which is cut flush to the edges 116 of chamber to provide a flat third surface 118. The vacuum chamber 94 is similar in shape to a cuboid and has one open face. This open face allows access to 10 the third surface 118 of the sponge material 112 whilst all other surfaces are surrounded. The vacuum pump 94 also includes a pump (not shown) used for removing the air from within the enclosure. Located across the open face adjacent the third surface 118 of the sponge material 112 is the membrane portion 15 114. This membrane is a thin film of flexible solid material and an example of a suitable material is clingfilm or other thin film polymer materials. Clingfilm is used in this example to replicate the epiretinal membranes or internal limiting membranes of the eye and has a predetermined thickness between 0 4-20 microns, although other membranes or tissues could also be replicated using different films of different thickness, different material properties and friction coefficients. The membrane portion 114 in this example adheres to the third surface 118 of the sponge material 112 by the removal of air from the 25 vacuum chamber 94. The third surface 118 creates a seal along the edges of the open face of the vacuum chamber as the air is removed 94 decreasing the pressure within. This decreased pressure forces the air on the outside of the chamber to push down on the membrane portion 114 adhering it to the third surface 30 118 of the sponge material 112. Other methods of adhering the third surface 118 to the resiliently deformable material 112 includes using a glue or adhesive. The strength of this adhesive layer can be increased or decreased by varying output of the pump. Increasing the pump output (for example by increasing the voltage) increases amount of air removed from the chamber therefore increasing the adhesion of the membrane portion 114 to the third surface 118 of the sponge material 112. Different methods of using the apparatus 10 and the eye 5 surface replica 110 will now be described technical comparisons between different surgical tools, quality control, a teaching aid and experimental analysis. Firstly, before any measurements or comparison between surgical tools can begin the surgical tool and testing sample 10 20 need to be set up and correctly positioned. In the case of testing forceps 12, the forceps 12 are placed into the clamp 26 such that the clamp 26 is holding onto the handle 14 above the gripping portion 82. The testing sample 20 is moved into position P and checked that the central portion of the membrane LO 5 89 of the testing sample is new and not damaged. If the testing C\J sample 20 needs changed the stepper motors that control the conveyor wheels 92 is turned on. The rotation of the wheels 92 pulls the sample belt 90 around and moves the used testing sample along the second axis 36. A new testing sample 20b can then be ¢-^20 replaced into position P, with the vacuum pump 94 being turned on to hold it in place. Depending on where the forceps 12 are positioned relative to the central portion of the membrane 89 of the testing sample 20 the forceps are moved such that they are directly above position P and therefore the testing sample 25 20. If the forceps 12 are not directly above the testing sample 20 the second and third arms 52 and 58 are moved accordingly, with the second arm 52 moving the forceps 12 along to the second axis 36 and the third arm moving the forceps along the third axis 38. When the second actuator 30 is turned on, the second 30 rod 50 begins to rotate. This rotation causes the threads of the first at rod 50 to engage with the threads of the first aperture of the first attachment (not shown) moving the attachment along the rod. Depending on which direction the rod 50 is rotating determines in which direction along the second axis 36 the first attachment will move. When considering figure 1, this will either be left or right. As the first attachment is also attached to the first actuator 28 of the first arm 46, 5 which in turn is attached to the fourth arm 68 and therefor the clamp 26, the forceps 12 also move along the second axis 36. As all fours arms (first, second, third and fourth, 46, 52, 58 and 68 respectively) are attached to each other through their corresponding attachments, when one arm moves in a specific 10 direction this in turn moves the clamp 26 and therefore the forceps 12 in that specified direction. This process is also repeated to move the forceps 12 along the third axis 38. When the third actuator 32 is turned on the third threaded rod 56 rotates. The threads on the third rod 56 engage with the threads on the second aperture of the second attachment 60. As the third rod 56 rotates further the second attachment begins to move along the third axis 42. This movement is either forwards or backwards relative to the testing sample 20, therefore moving the forceps 12 in that direction as well. Once the forceps 12 are located directly above the testing sample 20 the comparisons or testing can begin. When comparing the differences between a set of different forceps 12 for use in ophthalmic surgery the apparatus 10 and the eye surface replica 110 is used to test the force required 25 to pinch and peel the membrane portion 114 away the sponge material 112. For this procedure the testing sample 20 is in the form of the eye surface replica 110. The forceps 12 are lowered towards the eye surface replica 30 110 using the first arm 46. This is achieved by turning on the first actuator 28 which begins to turn the first threaded rod 44. The thread of the first rod 44 engages with the thread of the third threaded aperture of the third attachment 70 located on the fourth arm 68. As the clamp 26 also extends from the fourth arm 68 the forceps in turn move along the first axis 34 towards the eye surface replica 110. Once the forceps 12 make contact with the central portion 5 89 of membrane portion 114 closure of the tip 16 can begin. The fifth and sixth actuators 40a and 40b are turned on causing the fourth and fifth rods 80a and 80b to rotate, thereby moving the first and second surfaces 86a and 86b of the forceps controllers 84a and 84b towards the gripping portion 82 of the forceps 12. 10 Once the first and second surfaces 86a and 86b make contact with the gripping portion 82 the tip 16 of the forceps begins to close. As the contact between the gripping portion 82 and the surfaces increases so too does the force between them. This force is measured by the first and second sensors 22a and 22b. One of each sensor is located on the forceps controllers 84a and 84b and therefore the force created by each surface 86a and 86b on the gripping portion 82 can be measured. As the tip 16 closes it begins to pinch the central portion 89 of the membrane portion 114. The first arm 46 is then raised to check if enough force was used during the pinch to peel the membrane portion 114 off the sponge material 112. That is, that the forceps are able to maintain a grip on the membrane sufficiently that the membrane tears and can be peeled from the sponge material. If the membrane 114 has not peeled off the 25 procedure would be determined as unsuccessful. The process of peeling the membrane portion 114 is repeated with increased increments of force on the gripping portion 82. If the membrane is not achieving a successful pinch the forceps 12 may need to be moved further down into the testing sample 20 using the first 30 actuator 28 of the first arm 46. The downward force of the forceps 12 into the membrane 114 is measured and recorded by the third sensor 24. The forces are measured at repeated tests until a successful procedure is completed and at that successful test the forces, specifically the gripping force on the gripping portion 82 of the forceps measured by the first and second sensors 22a and 22b and, the downward force from the tip of the forceps moving into the membrane 114 measured by the third sensor 5 24 are recorded. Once a successful procedure has been achieved a new sample can moved into position P. The pump of the vacuum chamber 94 is turned off releasing the adhesive force between the sponge material 112 and the membrane portion 114. The vacuum chamber 10 94 is moved away from the sample belt 90 by turning on the sixth actuator 100. The sixth actuator 100 rotates the sixth threaded rod 104 which engages the threads of the fourth attachment 106 moving it down and therefore the vacuum chamber 94. The stepper motors that control the sample belt 90 and wheels 92 is then turned on. This moves a new undamaged section of membrane 114 into position P, allowing the vacuum chamber 94 to be moved back up again exposing the third surface 118 of the sponge material 112. Once the pump to the vacuum chamber 94 is turned on again the membrane portion 114 forms a seal around the edges 116 of the vacuum chamber 94 creating the adhesion needed between the third surface 118 of the sponge material 112 and the membrane portion 114, creating a new sample to work on. The forceps 12 are removed and replaced with a different set of forceps and the process is repeated with the different 25 forceps and the force used to successfully pinch and peel the membrane portion 114 is measured and recorded for each. Thus, providing the information required to make a comparison therebetween. When using the apparatus 10 to teach a new surgeon an 30 ophthalmic procedure the apparatus is used as follows. The first and second sensors 22a and 22b can be used to measure the force necessary for pinching and peeling the membrane 114 away from the sponge material 112. The data measured from the sensors can give the new surgeon an indication on the amount of force required to grip the gripping portion 82 of the forceps 12 during the pinch and peeling procedure. Furthermore, the third sensor 24 can measure and record the force applied to the eye surface 5 replica 110. This data can show the new surgeon how much force is required to push into the membrane 114 to achieve a successful pinch. Additionally, the third sensor data can highlight the problems with excessive force that could potentially pierce through the membrane 114. Pressure sensors could also be used 10 to provide information on the pressure level in the chamber 94. Changes in pressure within the chamber would indicate a leak in the chamber 94 that would correspond to the size of the breach in the membrane 114. It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the protection which is defined by the appended claims. For example, you could remove the clamp and use a device that holds the surgical tool and provides the manipulation force to the gripping portion of the forceps. A further example, other surgical instruments could be used for testing on the apparatus such as scalpels, needles or scrapers . 25 Another example is the movement of the four arms using actuators, rods and attachments. Any appropriate method could be used to mechanically and electronically move the arms (and therefore the forceps) to undertake a procedure, such as servomotors and microcontrollers. 30

Claims

04 04 251. A method for testing forceps, comprising:providing at least one testing sample comprising at least one 5 resiliently deformable material having a surface and at least one membrane portion adhered to said surface of said material;adjusting the strength of said adhesion;providing at least one instrument manipulator for controlling said forceps and wherein said instrument manipulator further 10 comprises at least one first motor for moving said forceps towards and away from said testing sample and at least one second motor for opening and closing said forceps;providing at least one sensor for measuring a force on said testing sample applied by said forceps;15 using said instrument on said testing sample; andreceiving data from said sensors.

2. A method according to claim 1 further comprising:undertaking a simulated surgical procedure;determining whether said procedure was successfully achieved;2 0 andvarying said force applied by said surgical tool and repeating said procedure until successfully achieved.

3. A method according to claim 1 further comprising:undertaking a simulated surgical procedure by varying said force 25 applied by said surgical tool;determining whether said procedure was successfully achieved as the force varies; andrecording said sensor data at the point which said procedure was successfully achieved.04 04 254. A method according to claim 2 wherein said surgical tool further comprises forceps and further comprising the steps:moving said forceps in a first direction towards said sample thereby applying a first force to said sample;5 applying a second force to said forceps thereby closing ends of said forceps and engaging said sample; andmoving said forceps in a second direction away from said sample.

5. A method according to claim 4 further comprising measuring said first force using a load cell.10 6. A method according to any preceding claim furthercomprising analysing said data by comparing between different surgical instruments used.7 . An apparatus for testing forceps, the apparatus comprising:at least one instrument manipulator for holding and controlling 15 at least one forceps and wherein said instrument manipulator further comprises at least one first motor for moving said forceps towards and away from said testing sample and at least one second motor for opening and closing said forceps;at least one testing sample comprising at least one resiliently 20 deformable material having a surface and at least one membraneportion adhered to said surface of said material;means for adhering said membrane portion to said resiliently deformable material; andat least one sensor for measuring a force applied by said forceps 25 to the testing sample.

8. An apparatus according to claim 7 wherein said sensor further comprises a plurality of sensors including a first sensor for measuring a first force applied by said surgical tool and a second sensor for measuring a second force applied to the 30 testing sample.

9. An apparatus according to claims 7 to 8 further comprisingmeans for adjusting and standardising the strength of adhesion.

10. An apparatus according to claims 7 to 9 wherein said membrane portion is adhered to said surface by a vacuum or 5 adhesive.

11. An apparatus according to claim 10, wherein variation of the adhesion of said membrane portion is achieved by variation of the vacuum applied.

12. An apparatus according to any of claim 7 to 11, wherein 10 said testing sample further comprises an elongate sheet being provided on a first roller and drawn across said resiliently deformable material onto a second roller.

13. An apparatus according to any of claims 7 to 12, whereinmaterial.said resiliently deformable material further comprises a sponge

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