Simulated tissue structures and methods

Abstract

To provide simulated tissue structures and manufacturing methods.SOLUTION: Simulated tissue structures (10) are particularly useful for placement inside abdominal simulators for practicing laparoscopic surgical techniques. One simulated tissue structure (10) includes a combination of two materials that are attached together, where one of the materials forms a hollow anatomical structure configured to house the other material. The two materials are attached in an anatomically advantageous manner such that the inner surface of the outer material strictly conforms to the outer surface of the inner material. Another simulated tissue structure includes a plurality of layers, where at least one layer is applied by printing at least one stencil to impart one or more functional characteristics to the simulated tissue structure.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] This application relates to surgical training tools, particularly to simulated tissue structures and organ models for teaching and practicing surgical procedures or surgical techniques, and methods for manufacturing the same.

[0002]

Description of Related Applications

Background Art

[0003] Highly skilled techniques are generally required for surgeons in surgery, particularly for performing laparoscopic surgical procedures or surgical techniques. In laparoscopic surgery, several small incisions are made in the abdomen to allow the insertion of trocars or small diameter cylindrical tubes, about 5 to 10 millimeters in diameter, through which surgical instruments and a laparoscope are placed into the abdominal cavity. The laparoscope illuminates the surgical field and sends an enlarged image from inside the body to a video monitor, which provides an enlarged view of the organs and tissues to the surgeon. The surgeon performs the surgery by operating the surgical instruments placed through the trocar while observing the live video feed on the monitor. Since the surgeon does not directly observe the organs and tissues with the naked eye, visual information is obtained from the two-dimensional image on the monitor rather than a three-dimensional observation. The loss of information when displaying a three-dimensional environment with a two-dimensional image is considerable. In particular, the depth perception decreases when observing a two-dimensional image as a guide for operating the instrument in three dimensions.

[0004] Furthermore, since the trocar is inserted through a small incision and positioned against the abdominal wall, the instrument's operation is restricted by the abdominal wall, which acts as a fulcrum (lever fulcrum) for the instrument. This fulcrum action defines a point of angulation that constrains the instrument to a limited movement. Additionally, hand movements in one linear direction amplify the movement of the tip in the opposite direction. Not only is the instrument's movement observed on the screen in the reverse direction, but the amplified tip movement is determined by how much of the instrument's length is above the abdominal wall. This lever action not only amplifies the movement but also amplifies the force at the tool tip that is reflected back to the user. Therefore, operating an instrument with a fulcrum requires deliberate learning and training and is not intuitively obvious.

[0005] Furthermore, surgical instruments are positioned through ports equipped with seals, and these seals cause stick-slip friction caused by the reverse direction of the tool. For example, stick-slip friction may occur from the reverse direction of the tool when there is a sudden change from tension to pressure on the tissue. During such motion, the rubber components of the seal rub against the tool shaft, thereby creating friction or motion between the seals, and then, overcoming the friction, the instrument slides against the seal. Stick-slip friction or oil-canning at the interface between the seal and the instrument generates non-linear forces.

[0006] Hand-eye coordination skills are necessary, and these skills must be practiced, especially by correlating hand movements with tool tip movements through observation on a video monitor. Furthermore, in laparoscopic surgery, the sensation received through touching the tools is reduced. Because tactile sensation is diminished or distorted, surgeons must develop a set of core tactile skills that underpin skilled laparoscopic surgery. Acquiring all of these skills is one of the main challenges in laparoscopic training, and the objective of this invention is to improve systems and methods for training laparoscopic skills and for the performance of techniques.

[0007] Not only must novice physicians learn laparoscopic skills, but experienced laparoscopic surgeons also strive to refine outdated skills and learn and practice new surgical techniques specific to newly introduced surgical procedures. While training in the operating room can be acquired, there has been growing interest in devising rapid and effective training methods, preferably outside the operating room. Surgeons who achieve a reasonable level of skill outside the operating room are well-prepared when they enter the operating room, thereby optimizing and mitigating beneficial operating room experience, reducing patient risk and costs. Various simulators (simulation training devices) have been devised and tested to familiarize surgeons with basic surgical skills outside the operating room. One example of a surgical simulator is the SIMSEI® Laparoscopic Training Device, manufactured by Applied Medical Resources Corporation, California, and described in U.S. Patent No. 8,764,452, which is cited herein by reference and whose entire description is incorporated herein by reference. The SIMSEI® laparoscopy training device employs three-dimensional living or artificial organs within a simulated abdominal cavity, hidden from direct observation by the user.

[0008] Using live human or animal organs in a laparoscopy simulator requires freshness of the internal organs. Furthermore, the use of live organs necessitates the construction of sanitary facilities to protect trainees from bacterial and other infections. Additional costs are also incurred for the sanitary management and sterilization of instruments used after surgical training. Additionally, the used live organs must be properly disposed of. Moreover, the odor of live organs can be unpleasant and may distract trainees from the techniques and skills. Therefore, artificial organs and tissues that mimic living organs and tissues are preferable and can thus replace live organs in surgical training.

[0009] Many artificial organs are used in surgical training as substitutes for organs of living humans or animals. Typically, these artificial organ models are made of silicone, urethane elastomer, styrene elastomer, etc. These artificial organs must respond appropriately when, for example, they are cut, manipulated, or sutured, and must provide the same feel and tactile properties as actual surgery. However, many artificial organs lack certain properties and realism necessary to bridge the gap between artificial and real organs. Furthermore, the degree of realism needs to be aimed at providing a means of teaching skills specific to laparoscopic skills training. Therefore, certain realism may be more important in the laparoscopic environment compared to the open surgical environment. Thus, there is a demand for artificial organs and tissues, and in particular artificial organs and tissues targeted for laparoscopic skills training. This invention provides novel artificial organs and tissues that are realistic and targeted for laparoscopic skills training. This invention also provides methods for manufacturing such artificial organs and tissues. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] U.S. Patent No. 8,764,452 [Overview of the project]

[0011] According to one aspect of the present invention, a simulated tissue structure and a method for manufacturing the simulated tissue structure are provided. The simulated tissue structure comprises a combination of two types of materials attached to each other, one of which forms a hollow anatomical structure configured to accommodate the other material. The two types of materials are attached in an anatomically advantageous manner such that the inner surface of the outer material closely matches the outer surface of the other material. Furthermore, the internal material has different and more rigid properties than the external material, and the anatomical geometric shape formed by the external material makes it difficult to achieve insertion of the internal material into the external geometric shape which would normally damage the external geometric shape, and reduces the realism resulting from necessary compensatory measures, such as repair and bonding, that would result from such damaging insertion. The manufacturing method of the present invention comprises the step of directly applying a first material onto a second material in an uncured, solid state to completely or partially enclose or surround the second material, the second material defining the dimensions and shape of at least a portion of the first material and forming an integral and connected structure with the first material which is also easily removable from the mandrel.

[0012] According to another aspect of the present invention, a method for manufacturing a simulated tissue structure is provided. The method includes the step of preparing a mandrel having a proximal end, a distal end and a longitudinal axis, wherein the distal end of the mandrel includes an interlock portion of a certain length. The method includes the step of preparing an inner portion of the simulated tissue structure. The inner portion has a lumen that is dimensioned and shaped to receive the interlock portion, such that the entire length of the interlock portion is located within the lumen. The method includes the step of fitting the inner portion onto the mandrel. The method further includes the step of positioning the interlock portion of the mandrel within the lumen of the inner portion. The method includes the steps of rotating the mandrel around its longitudinal axis, applying uncured silicone to the inner portion, curing the silicone to form an outer portion surrounding the inner portion, and removing the inner portion and the outer portion as a single unit from the mandrel.

[0013] A method for manufacturing a simulated tissue structure is provided according to another aspect of the present invention. The method includes the step of preparing a simulated anatomical structure. The method includes the step of preparing a mandrel having a longitudinal axis, a proximal end and a distal end. The mandrel is configured to be detachably attached to the simulated anatomical structure. The method includes the step of connecting the simulated anatomical structure to the mandrel at a location along the longitudinal axis. The method includes the step of rotating the mandrel and the connected simulated tissue structure. The method includes the step of applying a second material to the mandrel and the simulated anatomical structure in an uncured state. The method includes the step of curing the second material on the simulated anatomical structure and the mandrel to form a simulated tissue structure in which the simulated anatomical structure is enclosed within a thin shell of the second material. The simulated tissue structure has at least one lumen defined by the second material cured on the mandrel. This method includes the steps of attaching a second material to a simulated anatomical structure and removing the simulated anatomical structure together with the attached second material.

[0014] According to another aspect of the present invention, a simulated tissue structure is provided. The simulated tissue structure has a proximal and distal end of a first material, the first material being disposed within a thin shell of a second material having the proximal and distal end. The simulated anatomical structure is attached to the second material. The simulated anatomical structure has a first diameter and a first lumen at its proximal end, the second material has a second lumen with a second diameter at its proximal end, and the first lumen is substantially aligned with the second lumen.

[0015] According to another aspect of the present invention, a method for manufacturing a simulated tissue structure is provided. The method includes the step of preparing a flattened first substrate. The method includes the step of preparing a first stencil having at least one hole and adhering the first stencil to the first substrate. The method further includes the step of adhering a first stencil layer to the first substrate via the first stencil. The method includes the steps of removing the first stencil, preparing a flattened second substrate, and adhering the second substrate to the stencil layer and the first substrate while covering the stencil layer and the first substrate. The method further includes the step of adhering the second substrate to the first substrate.

[0016] According to another aspect of the present invention, a simulated structural body is provided. The simulated structural body has a flattened first base layer having a first face and a second face, with a substantially uniform thickness defined between the first and second faces. The simulated structural body has a flattened second base layer having a first face and a second face, with a substantially uniform thickness defined between the first and second faces. The second face of the second base layer faces the first face of the first base layer. The second base layer adheres to the first base layer. The simulated structural body further has at least one functional layer comprising a functional material disposed between the first and second base layers, the functional layer being formed via a stencil having at least one hole for adhering the functional layer. [Brief explanation of the drawing]

[0017] [Figure 1A] This is a top-down perspective view of a simulated tissue structure having an inner portion and an outer portion according to the present invention, showing that the outer portion forms an artificial fallopian tube and the inner portion forms an ectopic pregnancy area. [Figure 1B] This is a top-down perspective view of a simulated tissue structure having an inner portion and an outer portion according to the present invention, showing that the outer portion forms an artificial fallopian tube and the inner portion forms an ectopic pregnancy area. [Figure 1C]A cross-sectional perspective view seen from above of a simulated tissue structure having an inner part and an outer part according to the present invention, showing a state in which the outer part forms an artificial fallopian tube and the inner part forms an ectopic pregnancy part. [Figure 1D] A cross-sectional perspective view seen from above of a simulated tissue structure having an inner part and an outer part according to the present invention, showing a state in which the outer part forms an artificial fallopian tube and the inner part forms an ectopic pregnancy part. [Figure 2A] A perspective view seen from above of the inner part of FIG. 1 according to the present invention. [Figure 2B] A plan view of the inner part of FIG. 1 according to the present invention. [Figure 2C] A side view of the inner part of FIG. 1 according to the present invention. [Figure 2D] A bottom view of the inner part of FIG. 1 according to the present invention. [Figure 3A] An exploded assembly perspective view seen from above of the inner part, outer part, adapter and mandrel according to the present invention. [Figure 3B] A perspective view seen from above of the inner part, outer part, adapter and mandrel according to the present invention. [Figure 3C] A cross-sectional view of the inner part, outer part, adapter and mandrel according to the present invention. [Figure 3D] A cross-sectional perspective view seen from above of the inner part and outer part according to the present invention. [Figure 3E] A partial cross-sectional perspective view seen from above of the inner part and outer part according to the present invention. [Figure 4] A perspective view seen from above of the mandrel according to the present invention. [Figure 5] A perspective view seen from above of the mandrel and a part of the inner part according to the present invention. [Figure 6] A perspective view seen from above of the mandrel and a part of the inner part according to the present invention. [Figure 7A] A perspective view seen from above of the inner part according to the present invention. [Figure 7B] A plan view of the inner part according to the present invention. [Figure 7C] This is a side view of the inner portion according to the present invention. [Figure 7D] This is a side view of the inner portion according to the present invention. [Figure 8] This is a top-down perspective view of the mandrel according to the present invention. [Figure 9] This is a top-down perspective view of a portion of the mandrel and its inner part according to the present invention. [Figure 10] This is a top-down perspective view of a portion of the mandrel and its inner part according to the present invention. [Figure 11] This is a top-down cross-sectional perspective view of the simulated tissue structure according to the present invention. [Figure 12] This is a top-down perspective view of the inner portion and mandrel according to the present invention. [Figure 13] This is a top-down cross-sectional perspective view of the simulated tissue structure according to the present invention. [Figure 14A] This is a top-down partial cross-sectional perspective view of a simulated tissue structure according to the present invention. [Figure 14B] This is a top-down partial cross-sectional perspective view of a simulated tissue structure according to the present invention. [Figure 15] This is a plan view of the stencil according to the present invention. [Figure 16] This is a plan view of the stencil according to the present invention. [Figure 17] This is a plan view of the stencil according to the present invention. [Figure 18] This is a plan view of the stencil according to the present invention. [Figure 19] This is a top-down perspective view of a stencil and a portion of a simulated tissue structure according to the present invention. [Figure 20] This is a top-down perspective view of a stencil and a portion of a simulated tissue structure according to the present invention. [Figure 21] This is a top-down perspective view of the simulated tissue structure according to the present invention. [Figure 22] This is a top-down cross-sectional perspective view of a portion of a simulated tissue structure according to the present invention. [Figure 23]This is a cross-sectional perspective view of a portion of the simulated tissue structure according to the present invention, as seen from above the stencil. [Figure 24] This is a top-down cross-sectional perspective view of the simulated tissue structure according to the present invention. [Figure 25] This is a top-down cross-sectional perspective view of a portion of a simulated tissue structure according to the present invention. [Figure 26] This is a top-down cross-sectional perspective view of the simulated tissue structure according to the present invention. [Figure 27] This is a top-down cross-sectional perspective view of a simulated tissue structure according to the present invention. [Figure 28] This is a top-down perspective view of the stencil according to the present invention. [Figure 29] This is a top-down perspective view of the base layer and stencil according to the present invention. [Figure 30] This is a perspective view from above of the first base layer and the first stencil layer according to the present invention. [Figure 31] This is a cross-sectional perspective view of the first base layer, the first stencil layer, and the second base layer according to the present invention, as seen from above. [Figure 32] This is a cross-sectional perspective view of the first base layer, the first stencil layer, the second base layer, and the second stencil according to the present invention. [Figure 33] This is a cross-sectional perspective view of the first base layer, the first stencil layer, the second base layer, and the second stencil layer according to the present invention, as seen from above. [Figure 34] This is a top-down cross-sectional perspective view of the first base layer, first stencil layer, second base layer, second stencil layer, and third base layer according to the present invention. [Figure 35] This is a cross-sectional perspective view of the first base layer, the first stencil layer, the second base layer, the second stencil layer, the third base layer, and the third stencil according to the present invention. [Figure 36] This is a cross-sectional perspective view of the first base layer, first stencil layer, second base layer, second stencil layer, third base layer, and third stencil layer according to the present invention, viewed from above. [Figure 37] This is a top-down cross-sectional perspective view of the simulated tissue structure according to the present invention. [Figure 38] This is a top-down cross-sectional perspective view of a simulated tissue structure according to the present invention. [Figure 39] This is a top-down cross-sectional perspective view of a simulated tissue structure according to the present invention. [Modes for carrying out the invention]

[0018] Next, referring to Figures 1A to 1D, the simulated tissue structure 10 of the present invention is shown. The simulated tissue structure 10 has a silicone outer portion 12 having an outer surface and an inner surface. The inner surface defines an internal cavity 14. The internal cavity 14 is interconnected with at least one opening 16. The cavity 14 of the simulated tissue structure 10 in Figures 1A to 1D includes two openings 16, and the cavity 14 is lumen-like and elongated overall. In particular, the outer portion 12 is configured to have the dimensions and shape of at least a part of a tissue structure, organ, or anatomical structure. For example, as shown in Figures 1A to 1D, the outer portion 12 is shaped and sized to represent the fallopian tube or tubal tube of female anatomical structure. Figures 1B and 1C show a proximal extension that is longer than the proximal extension shown in Figures 1A and 1C to integrally form a Fallopian tube, and can be optionally connected to a separately formed Fallopian tube extension. The proximal opening 16 is preferably connected to an artificial uterus and / or a separately formed Fallopian tube extension, and the distal opening 16' has a longitudinal slit to mimic a Fallopian tube. The outer portion 12 is made of silicone, for example, platinum-cured room temperature vulcanization silicone (PCRTVS). The outer portion 12 may be made of any other form of silicone material, polymer, rubber, elastomer, etc.

[0019] The simulated tissue structure 10 further comprises an inner portion 18 positioned within the cavity 14 of the outer portion 12. The inner portion 18 has an outer surface and an inner surface. The inner surface of the outer portion 12 closely matches the outer surface of the inner portion 18. The foamed inner portion 18 is connected to the outer portion 12. In the configurations shown in Figures 1A to 1D, the foamed inner portion 18 is connected to the outer portion 12 near the distal end of the fallopian tube, and this foamed inner portion 18 is configured to represent an ectopic pregnancy and is therefore dark in color, for example, black or brown. The inner portion 18 is made of foam material. The foam material may be urethane foam, silicone foam, or any other suitable foam. When polyurethane foam is used for the inner portion 18, the silicone outer portion 12 does not adhere to the polyurethane foam to the same degree, and the silicone outer portion 12 is easily removable from the inner portion 18, thereby the silicone outer portion 12 is advantageous in facilitating and simulating the surgical removal of the simulated ectopic pregnancy. When silicone foam is used for the inner portion 18, the silicone outer portion 12 adheres more strongly to the silicone foam inner portion 18, and the silicone outer portion 12 is difficult to remove from the inner portion 18, which is advantageous in increasing the level of difficulty and the required surgical skill when removing the simulated ectopic pregnancy. The inner portion 18 has a width or outer diameter determined by the longitudinal axis, the outer circumference, and the outer circumference measured perpendicular to the longitudinal axis. The outer diameter of the inner portion 18 is less than or equal to the width or inner diameter of the outer portion at the same position along the longitudinal axis. The length of the inner portion 18 is shorter than that of the outer portion 12 along the longitudinal axis. The outer portion 12 located either proximal to the proximal end of the inner portion 18 or distal to the distal end of the inner portion 18 has a width or outer diameter smaller than the width or outer diameter of the proximal end of the inner portion, or a width or inner diameter smaller than the width or outer diameter of the distal end of the inner portion.In another embodiment shown in Figures 1A to 1D, the outer portion 12, located proximal to the proximal end of the inner portion 18 and distal to the distal end of the inner portion 18, each has a width or outer diameter smaller than the width or outer diameter of the proximal end of the inner portion and a width or inner diameter smaller than the width or outer diameter of the distal end of the inner portion. In this embodiment, the inner portion 18 is enclosed within the outer portion, thereby preventing its movement along the longitudinal direction. The inner portion 18 is trapped between constrictions provided in the outer portion at opposite ends of the inner portion.

[0020] Next, referring to Figures 2A to 2D, various diagrams of the inner portion 18 made of foam material are shown. The inner portion 18 has an outer surface and an inner surface. The outer surface is bulbous in shape. The inner portion 18 has a lumen 20 defined by the inner surface. The lumen 20 extends between a proximal opening 22 at the proximal end and a distal opening 24 at the distal end. The lumen 20 is configured to overlap the mandrel. Therefore, at least a portion of the lumen 20 has a non-circular cross-section, and as a result, the inner portion 18 does not move relative to the mandrel even when the mandrel rotates. The cross-sectional shape of the lumen 20 is hexagonal, but the present invention is not limited thereto, and the cross-section may be elongated, slotted, triangular, square, pentagonal, or any other shape that prevents the foam inner portion from rotating freely while positioned on the mandrel. The inner portion of the foam may be fixed to the mandrel 30 by means other than the cross-sectional shape of the lumen 20, for example, by a pin or other locking device.

[0021] As a variation, referring next to Figures 3A to 3E, the inner portion 18 may or may not have a lumen 20 configured to be attached to a mandrel. In contrast, the inner portion 18 is provided with a male boss 26 as shown in Figures 3A to 3E. The male boss 26 has an outer surface with a non-circular cross-section. The cross-section of the male boss 26, taken perpendicular to the longitudinal axis, may be elongated, slotted, triangular, square, pentagonal, hexagonal, or any other shape that prevents the inner portion from rotating freely while positioned on the mandrel 30. The mandrel 30 is a standard elongated cylindrical rod with a circular cross-section as shown in Figures 3A to 3C. An adapter 28 is provided, which is configured to be connected to the distal end of the mandrel 30. The adapter 28 has a female boss 32 with a modified portion that is dimensioned and shaped to receive a male boss 26 of the inner portion 18 to secure the inner portion 18 to the mandrel 30, so that the inner portion 18 does not rotate relative to the mandrel 30 even when the mandrel 30 is rotating during the manufacturing process. The formed inner portion 18 and the mandrel 30 are configured to have a geometric shape that forms an interlocking relationship between the mandrel 30 and the inner portion 18. This geometric shape is achieved during the design process and is incorporated into the mold used to manufacture both the forming mandrel and the formed inner portion 18. The shape between these two may be any geometric shape that prevents the components from rotating freely relative to each other. Figures 3D and 3E show the outer portion 12 connected to the inner portion 18 in the final product state as it is removed from the mandrel 30.

[0022] Next, a method for manufacturing the simulated tissue structure 10 will be described. A mandrel 30 is used to manufacture a simulated anatomical structure. Typically, the mandrel 30 is connected to a motor that rotates the mandrel 30 around its longitudinal axis. A mold, typically having the shape of a desired form, such as the shape of an anatomical part to be molded, is attached to the mandrel 30. When the motor is turned on, the mandrel 30 rotates and uncured silicone, such as uncured PCRTVS, is applied to the rotating mold connected to the mandrel 30. As the uncured silicone begins to cure, it takes the shape of the mold located below it. The uncured silicone is applied, for example, by painting, spraying, or dipping the mold in layers. Once the application of the silicone is complete, the uncured silicone cures, and the resulting simulated tissue structure 10 is then removed from the mold and mandrel 30, thereby creating a hollow tissue structure of the desired shape. Typical hollow organs that can be created using this method include the rectum, ovaries, fallopian tubes, vascular system, uterus, and other organs.

[0023] Referring next to Figure 4, the mandrel 30 of the present invention is shown. The mandrel 30 is an elongated cylindrical rod having a circular cross-section at its proximal end or another shape at its proximal end configured to be connectable to a motor. At least a portion of the mandrel 30, namely the interlock portion 36, is configured to interlock with the pre-formed foam inner portion 18. The interlock portion 36 is configured to be inserted into a complementary lumen 20 of the foam inner portion 18. In one modification, the interlock portion 36 has a hexagonal cross-section that is dimensioned to fit into a lumen 20 having a hexagonal cross-section. The foam inner portion 18 is designed to be part of the final simulated tissue structure 10. In one embodiment of the mandrel 30, the mandrel 30 has at least one anatomical portion 38. In the configuration shown in Figure 4, the anatomical portion 38 is located at the distal portion of the mandrel 30, the interlock portion 36 is located proximal to the anatomical portion 38 along the longitudinal axis, and the cylindrical portion of the mandrel 30 is located proximal to the interlock portion 36. The anatomical portion 38 is configured to represent at least a part of an anatomical structure. In particular, the anatomical portion 38 is configured to mimic the hollow portion of an anatomical structure. In Figure 4, the anatomical portion 38 is configured to mimic the fallopian tube or the distal end of a fallopian tube of a female anatomical structure. Thus, the anatomical portion 38 is curved, and this anatomical portion has a large-diameter distal end. The anatomical portion 38 is connected to the mandrel 30 at the location proximal to the interlock portion 36; however, the present invention is not limited thereto, and the interlock portion may be located between two anatomical portions 38 or may be formed as part of the anatomical portion 38. The portion of the mandrel 30 located proximal to the interlock portion 36 also serves as a second or proximal anatomical portion 38, such as the proximal end of the fallopian tube.

[0024] Next, referring to Figure 5, a mandrel 30 is shown positioned alongside the inner portion 18 according to the present invention. The inner portion 18 in Figure 5 is shaped like the ectopic pregnancy portion in Figures 2A to 2D. The proximal end 34 of the mandrel 30 is inserted into the distal opening 24 of the lumen 20 of the inner portion 18. The inner portion 18 is moved along the cylindrical portion of the mandrel 30 toward the interlock portion 36. The inner portion 18 slides along the longitudinal axis of the mandrel 30. The hexagonal portion of the interlock portion 36 of the mandrel 30 aligns with the hexagonal portion of the lumen 20 of the inner portion 18, and the interlock portion 36 of the mandrel 30 is inserted into the lumen 20 of the inner portion 18. The inner portion 18 locks securely onto the mandrel 30 in a slight interlocking fit that prevents it from rotating relative to the mandrel 30 or from easily sliding distally or proximal along the mandrel 30. The mandrel 30 is connected to the inner portion 18 at the location of the interlocking portion 36 by an interlocking fit as shown in Figure 6. In this case, the mandrel 30 and the mounted inner portion 18 are connected to a motor (not shown) configured to receive and connect to the proximal end of the mandrel 30. The motor is configured to rotate the mandrel 30 and the mounted inner portion 18 around their longitudinal axes.

[0025] As the mandrel 30 and the mounted inner portion 18 are rotated, uncured silicone, such as PCRTVS, is applied to cover at least the anatomical portion 38a and the inner portion 18, and, where applicable, the second anatomical portion 38b located proximal to the interlock portion 36 as shown in Figure 6. As the mandrel 30 rotates, the uncured silicone is applied to achieve the desired thickness of the material that will form the outer portion 12. The uncured silicone begins to cure, and additional uncured silicone can be applied continuously. The uncured silicone is applied to the mandrel 30 and the inner portion 18, covering them together. The uncured silicone is preferably applied using a brush, spray, or by dipping or other means. The rotation of the mandrel 30 prevents the silicone from curing and forming uneven coverage areas. After the silicone has cured, the outer portion 12 with a silicone layer is formed around the mandrel 30. Therefore, the outer surface of the inner portion 18 defines the dimensions and shape of at least a portion of the inner surface of the outer portion 12, and the outer surface of the anatomical portion 38 defines the dimensions and shape of at least a portion of the inner surface of the outer portion 12 in a substantially continuous manner, so that both the inner portion 18 and the anatomical portion 38 define the dimensions and shape of the outer portion 12. The anatomical portion 38 is located adjacent to the inner portion 18 which is positioned on the mandrel 30, and the outer portion of uncured silicone is applied to both of them in a seamless manner, thereby forming a one-piece simulated tissue structure 10. The inner portion 18 is removable from the mandrel 30 together with the outer portion 12, whereas the anatomical portion 38 of the mandrel 30 remains fixed to the mandrel 30. Therefore, the uncured silicone is applied to the inner portion 18, which is removable from the mandrel 30 and becomes integrated with and attached to the outer portion 12, in which case the anatomical portion 38, which serves as a mold for at least another portion of the outer portion 12, is not removable from the mandrel 30 when at least the outer portion 12 and the inner portion 18 are removed.

[0026] Once the silicone has cured, rolling the outer portion 12 on the second anatomical part 38b along the mandrel 30 toward the inner portion 18 or the proximal end of the mandrel 30 allows the inner portion 18 and the silicone outer portion 12 to be easily removed from the mandrel 30 as a single unit. Rolling the proximal end of the outer portion 12 helps reduce the frictional force acting between the outer portion 12 and the mandrel 30, facilitating the removal of the final anatomical model. As described above, if the inner portion 18 is made of silicone foam, the uncured silicone interlocks, attaches to, and bonds to the silicone foam more firmly when cured than if the inner portion 18 is made of urethane foam. This strong bond helps to easily remove the silicone outer layer 12 and the attached inner portion 18 together. Applying a mold release agent or resist to the cylindrical portion of the anatomical part 38 and the mandrel 30 can facilitate the removal of the outer portion 12 and the inner portion 18, resulting in the simulated tissue structure 10 shown in Figure 1.

[0027] This method allows for the creation of a fallopian tube with an ectopic pregnancy as described above, in which case the inner portion 18 mimics the ectopic pregnancy and the silicone outer portion 12 mimics the fallopian tube. This method can be used to create a wide range of other anatomical structures. Below, we describe a method for producing an ovary with a fallopian tube, including the ovary and cyst. Other anatomical structures that can be mimicked include a healthy uterus and a fibrous uterus. The form of the inner portion 18 may be rigid or flexible, and as mentioned above, this form can be made of urethane, silicone, or other materials. The simulated tissue may also be any material other than silicone that can be applied to the mandrel by dipping, painting, spraying, etc.

[0028] Furthermore, this method can be combined with the steps of preparing a mesh sleeve made of, for example, nylon mesh, fitting the mesh sleeve onto the mandrel 30, and applying the material for the outer portion 12, for example, uncured silicone. The uncured silicone is poured out and covers the mesh material and hardens integrally within the mesh. Similarly, the mesh attached to the uncured silicone hardens integrally together. The mesh advantageously allows the outer portion 12 to hold sutures for practice in suturing certain anatomical structures.

[0029] Next, referring to Figures 7A to 7D, various diagrams of the inner portion 18 made of foam material are shown. The inner portion 18 has an outer surface and an inner surface. The outer surface is bulbous in shape and is configured to represent a female ovary. The inner portion 18 has a lumen 20 defined by the inner surface. The lumen 20 extends into the inner portion 18 from a proximal opening 22 at its proximal end. The lumen 20 does not penetrate the inner portion 18 and has only one opening 22 at its proximal end. The lumen 20 is configured to overlap the mandrel 30. Therefore, at least a portion of the lumen 20 has a non-circular cross-section, and thus the inner portion 18 does not move relative to the mandrel 30 even when the inner portion 18 is attached to the mandrel 30 and the mandrel 30 rotates. The cross-sectional shape of the lumen 20 is hexagonal, but the present invention is not limited thereto, and the cross-section may be elongated, slotted, triangular, square, pentagonal, or any other shape that prevents the inner foam portion 18 from rotating freely while positioned on the mandrel 30. The inner foam portion 18 may be fixed to the mandrel 30 by means other than the cross-sectional shape of the lumen 20, for example, by a pin or lock. Naturally, the inner portion 18 may or may not have a lumen 20 configured to be attached to the mandrel. As a variation, the inner portion 18 is provided with a male boss 26 shown in Figures 3A to 3C for connecting the inner portion 18 to the mandrel 30. The inner portion 18 in Figures 7A to 7D has two flat outer surfaces connected to each other by two curved sides. The shape of the cross-section taken perpendicular to the longitudinal axis of the inner portion 18 may be oval, elliptical, elongated, or any other shape with a length that is long relative to its width. The outer surface of the inner portion 18 has a dimple 40. The dimple 40 is a depression formed on the outer surface of the inner portion 18. The dimple 40 is sized and shaped to receive an artificial cyst, fibroid, or tumor (not shown). The artificial cyst, fibroid, or tumor 42 is made separately to mimic a real cyst, fibroid, or tumor and is sized and shaped to fit into the dimple 40.The artificial cyst, fibroid, or tumor is preferably made of silicone or foam and preferably colored appropriately to accurately represent the respective structure. If necessary, the artificial cyst, fibroid, or tumor 42 is placed in the dimple 40 using some adhesive, and then the uncured silicone of the outer portion 12 is applied to both the dimple insert and the inner portion 18. In another embodiment, the dimple 40 is not provided, and the simulated cyst 42 is attached directly to the outer surface of the inner portion 18. In yet another embodiment, the simulated cyst 42 is formed integrally with the inner portion 18 and, optionally, made of the same material as the inner portion 18.

[0030] Referring now to Figure 8, the mandrel 30 of the present invention is shown. The mandrel 30 is an elongated cylindrical rod with a circular cross-section. The mandrel 30 has an interlock portion 36 configured to interlock with a pre-formed foam inner portion 18. In one embodiment shown in Figure 8, the mandrel 30 has an interlock portion 36 located at the distal end 34 of the mandrel 30. The interlock portion 36 is configured to be inserted into a complementary lumen 20 of the foam inner portion 18. In one modification, the interlock portion 36 has a hexagonal cross-section that is dimensioned to fit into a lumen 20 having a hexagonal cross-section. The foam inner portion 18 is designed to be part of the final simulated tissue structure 10.

[0031] Next, referring to Figure 9, the mandrel 30 is shown in a state adjacent to the inner portion 18 according to the present invention. The inner portion 18 in Figure 9 has a similar shape to the ovary in Figures 7A to 7D. The distal end 34 of the mandrel 30 is inserted into the proximal opening 22 of the lumen 20 of the inner portion 18. The hexagonal portion of the distal end 34 of the mandrel 30 is aligned with the hexagonal portion of the lumen 20 of the inner portion 18, and the interlock portion 36 of the mandrel 30 is inserted into the lumen 20 of the inner portion 18. The inner portion 18 locks securely onto the mandrel 30 in a slight interlocking relationship. The mandrel 30 is connected to the inner portion 18 by an interlocking fit as shown in Figure 10. In this case, the mandrel 30 and the attached inner portion 18 are connected to a motor (not shown) configured to receive and connect to the proximal end of the mandrel 30. The motor is configured to rotate the mandrel 30 and the mounted inner portion 18 around their longitudinal axis.

[0032] A simulated cyst, tumor, or other anatomical morphology is placed within the dimple 40 and held in place by attachment or simultaneous application of a wet silicone that constitutes the outer portion 18. As the mandrel 30 and the attached inner portion 18 and the attached cyst are rotated, uncured silicone, such as PCRTVS, is applied to cover at least the inner portion 18 and the attached cyst. As the mandrel 30 rotates, more uncured silicone is applied to achieve the desired thickness of the material. The uncured silicone begins to cure, and additional uncured silicone can be applied continuously. It is preferable to apply the uncured silicone to both the inner portion 18 and the mandrel 30. The uncured silicone is preferably applied using a brush, spray, or by dipping or other means. The rotation of the mandrel 30 prevents the silicone from curing and forming uneven coverage areas. After the silicone has fully cured, an outer portion 12 with a silicone layer is formed around the mandrel 30. Therefore, the outer surface of the inner portion 18 determines the dimensions and shape of at least a portion of the inner surface of the outer portion 12. Once the silicone has cured, it is best to roll a portion of the inner portion distally along the longitudinal axis at the mandrel 30. It is best to grasp the inner portion 18 and pull it distally, thereby removing the structure from the mandrel 30. The foam inner portion 18 and the silicone outer portion 12 can be easily removed from the mandrel 30 as a single unit. The resulting simulated tissue structure 10 after removal from the mandrel 30 is shown in Figure 11. As described above, when the inner portion 18 is made of silicone foam, the uncured silicone interlocks and bonds to it more strongly with the silicone foam when cured than when the inner portion 18 is made of urethane foam. This strong bond helps to easily remove the silicone outer layer 12 and the attached inner portion 18 as a single unit. Applying a mold release agent or resist to the mandrel 30 facilitates the simultaneous removal of the outer portion 12 and the inner portion 18, resulting in the acquisition of a simulated tissue structure 10.

[0033] Referring next to Figure 12, another form is shown in which the inner portion 18 is dimensioned and shaped to resemble a uterus. The inner portion 18 is shown with one or more simulated cysts 42 attached to the inner portion 18 at the placement of the dimples 40, where the dimples 40 are provided for seating the simulated cysts 42. It should be noted that throughout the specification, the simulated cysts are used without distinction from tumors, fibroids, or other similar anatomical or general surgical targets. The inner portion 18 has a lumen 20 that opens at its proximal end. The lumen 20 is dimensioned and shaped so that the inner portion 18 does not rotate relative to the mandrel 30. The mandrel 30 is short so that the resulting simulated tissue structure 10 is shaped substantially like a real one. Using the same method as described above to form the resulting structure 10 shown in Figure 13, the simulated tumor 42 is embedded within this structure 10 between the outer portion 12 and the inner portion 18. The lumen 20 at the proximal end of the simulated tissue structure 10 mimics the uterine canal, and the inner portion 18 is made of foam, so that the doctor can grasp and pull the simulated tissue structure during the simulated surgery without the risk of tearing that may occur if the inner portion were made of, for example, silicone. The doctor approaches the target cyst 42, cuts open the outer portion 12, and then detaches the cyst 42 from the simulated uterus 10.

[0034] The present invention advantageously provides a simulated tissue structure 10 combining a silicone material and a foam material, the silicone material and the foam material being attached in an anatomically advantageous manner to represent an ectopic pregnancy, cyst, fibroid, tumor or other anatomical part when combined with a hollow anatomical structure. The method includes the step of forming a one-piece structure by directly applying silicone to the inner portion and molding the outer portion, while simultaneously molding the outer portion integrally with the inner portion. Otherwise, the silicone outer portion would have to be formed separately on a mandrel, cured, and then removed. Next, the molded hollow silicone structure would have to be cut open, and then the foam component would be inserted into the silicone structure. Cutting open the silicone structure is the only way to accommodate the dimensions and shape of the foam component while retaining anatomical features, such as a thin tubular structure, attached to one or more ends of the foam inner portion. After inserting the foam inner portion, the cut silicone would then have to be bonded together and put back together, thereby completing the anatomical structure in question and creating the underlying simulated tissue structure. By using the inner foam portion 18 as part of a molded mandrel that is removable and integrated into a simulated tissue structure, the present invention advantageously omits several steps in the manufacturing process, such as cutting the hollow silicone shape, inserting the inner foam portion into the opening created by the cut, and then bonding and closing the opening upon completion. Cutting the hollow shape is necessary due to the dimensions of the inner portion relative to the surrounding tubular anatomical structure. When the foam insert is pushed into the opening provided in the hollow silicone shape, tearing of the silicone occurs during the manufacturing process as a result. Thus, the present invention solves many problems in creating an ideal simulated tissue structure. Furthermore, removing the silicone material from the mandrel 30 is complex, because silicone is, as is well known, sticky, and complex shapes, such as a Fallopian tube with an ectopic pregnancy, can be extremely difficult to remove from the mandrel without damaging the workpiece.The addition of foam inserts to the mandrel significantly reduces the difficulty of removing the silicone component from the mandrel, because a portion of the silicone component is attached to a foam insert that slides off easily, rather than being directly attached to the mandrel. It is preferable to first bundle the portion of silicone to be attached to the anatomical part 38 or the cylindrical portion of the mandrel 30 near the inner foam portion, so that the inner portion 18 can then slide off easily from the mandrel 30. As described above, the foam can serve just as a filler or tissue layer of varying densities to help represent separate components, such as cysts, fibroids, or tumors as a whole, or to maintain a three-dimensional shape or to define and reproduce certain anatomical characteristics. In addition, curing the silicone on the foam adds an element of difficulty to the simulated training procedure, which may be desirable in certain situations, because separation between tissue planes is not always easy. The present invention provides a simulated tissue structure that combines all of these advantages. Furthermore, as described above, the modifications may include various material selections for the inner portion 18, including different densities of foam, and plastics can be used depending on the desired feel of the anatomical components.

[0035] The simulated tissue structure 10 of the present invention is particularly suitable for laparoscopic procedures, and such a simulated tissue structure can be used together with a laparoscopic training device. However, the present invention is not limited thereto, and various surgical procedures can be practiced equally efficiently using the simulated tissue structure 10 of the present invention alone.

[0036] Referring next to Figures 14A and 14B, a simulated tissue structure 110 according to the present invention is shown. The simulated tissue structure 110 has at least a first layer 112, a second layer 114, and at least one screen or stencil layer 115 positioned between the first layer 112 and the second layer 114. The first layer 112 and the second layer 114 are typically made of silicone and formed into flat sheets in which each layer has a first surface and a second surface, with a substantially uniform thickness between the first and second surfaces. The first and second layers 112,114 are substantially identical and flat, and in one embodiment, at least one of the first and second layers 112,114 is transparent or translucent, so that at least one screen layer 116 positioned between the first layer 112 and the second layer 114 is visible through one of the first and second layers 112,114. The screen layer 116 includes a resist, a release agent or delaminating agent, an adhesive, silicone, hydrogel, or other material coated using a screen, stencil, plate, mask, or other image transfer method. Figures 14A and 14B show, in particular, three silicone layers and a total of two screen layers located between the three silicone layers, each screen layer positioned between two adjacent silicone layers. The process for manufacturing the simulated tissue structure 110 includes the steps of casting a sheet of silicone or other elastic material to form a substrate and coating a resist, adhesive, silicone or other material using a screen, stencil, or other image transfer method to form a functional stencil layer, which is coated onto a cured substrate, and then covering this cured substrate with an uncured substrate, and such manufacturing process further includes the step of repeating this process after the uncured substrate has cured to form a thickness of material with desirable properties for surgical simulation.

[0037] One form of this process involves applying a mold release agent or resist to a silicone sheet in a desired pattern using a stencil. By using a stencil, screen, or lithographic plate, the resist coating can be adjusted to form a specific pattern, such as dots, halftones, or other patterns, to give a certain percentage of adhesion or relative adhesion between two material sheets in a specific area. For example, if the stencil includes a pattern with approximately 50% open areas, and this stencil is used to adhere a stencil layer of resist material to a silicone layer of equal area, the adhesion of adjacent silicone layers will be reduced by approximately 50%. The mold release agent / resist pattern is applied to a first surface of a pre-cured silicone sheet via a stencil, screen, or other plate. Next, this pre-treated sheet is placed on top of an uncured silicone sheet, which may or may not remain in the mold. The combination of the cured silicone sheet, the stencil layer, and the uncured silicone layer is given time to cure. Upon curing, a sandwich-like structure with variable interface properties across the interface plane due to the stencil layer is obtained. Repeating this method over multiple layers yields a simulated tissue of a specified thickness with desired properties, including, and / or separately from, material and visual properties, as well as variability of the X-Y plane interface and properties along the Z axis. A high percentage of the area covered by dots of mold release agent / resist via a stencil, plate, or screen creates a tissue that feels smooth and is easy to peel. A low percentage of the area covered by dots of mold release agent / resist via a stencil, plate, or screen creates a solid block that feels hard, is more one-piece, and is difficult to cut or peel with surgical instruments.

[0038] In another configuration, instead of applying a resist or mold release agent to a layer of cured silicone via a stencil, plate, or screen, silicone or other adhesives are applied to a layer of cured silicone in a specific pattern or in halftones via a stencil, plate, mask, or screen. Then, this layer of cured silicone is used to bond two pre-cured silicone sheets, thereby selectively adhering them with variable adhesion along the interface plane. This is then combined with additional layers to create a multilayer structure with variable adhesion along the Z-axis within the interface plane. Thus, the stencil layer is a functional layer, the function of which can be selected from the group consisting of adhesion, release, and color.

[0039] Patterns on stencils, plates, or screens are not limited to dots; materials can be applied to create stencil layers for simulated tissue structures. In this case, lines, webs, ellipses, squares, curves, or other shapes of varying thicknesses and colors can be created by stencil layers to mimic vascular systems, muscular systems, adipose layers, or other complex organs and tissues in two dimensions, with the structure interacting with adjacent layers as it transitions across multiple layers and continues as a three-dimensional construct. This method is used to create the desired overall thickness of the material for tissue structures to be used in surgical simulations.

[0040] Furthermore, by using each of these techniques—which employ stencil, screen, or plate-making methods to apply resist or adhesive—along with patterned silicone sheets and casting dishes, the feel and response of the material can be further refined. Additionally, color can be introduced to mimic different anatomical layers and structures. The addition of color assists user navigation during surgical simulations and aids user evaluation after the simulation practice is complete. For example, a surgeon practicing incisions might know that an incision passing through one or more sublayers is too deep if a particular color, such as red, becomes visible; in this case, red is provided to the functional layer to help perform the function of a visual indicator for training purposes. Naturally, color can be used at least in the functional layer, thereby providing various surgical markers, anatomical structures, and targets, such as tumors. Similarly, for example, after the simulation training is complete, the layers can be evaluated to verify the accuracy of the procedure for training and evaluation purposes. For example, layers can be separated and examined, thereby determining whether the incision penetrated too deeply or whether care was taken to separate layers without making unnecessary cuts into undesirable anatomical structures.

[0041] In one embodiment, blocks of simulated tissue are created using the resist method described above, thereby creating blocks of simulated tissue having multiple layers, in which case these layers transition from skin-colored to white and then to red. When working with this multilayer simulated tissue structure having a gradient of color and / or interface adhesion properties, the separation of the skin-colored and white layers becomes a point of interest in simulation practice. This point of interest is also thought to stem from the respect for tissue-related surgical techniques that, in evaluation, illustrate the surgeon's skill in separating muscle fibers rather than cutting them when making an incision in the abdomen, for example. The variable adhesion properties of the simulated tissue model are used to facilitate training of muscle fiber separation and other points of interest regarding tissue-related techniques. The colored layers can be used for post-practice evaluation by examining the structure and checking whether the cut extends, for example, through the white layer into the red layer. For example, if the red layer is cut, the surgeon and evaluator will know that the cut is too far into the red layer and that the training needs to continue. The present invention advantageously provides trainees with evaluation means, particularly regarding separation, while improving the feel and function of the simulated tissue structure, especially in the training environment, while also providing raw feedback to the surgeon.

[0042] Specific desired properties can be achieved by creating stencils, screens, masks, or plates, such as silkscreens or lithographic plates, which are used to create simulated tissues for specific human and animal anatomical structures. A high degree of realism can be achieved in surgical simulations by controlling the percentage area and shape of the adhesive or resist between two layers, such as silicone, Kraton, or hydrogel, and such a high degree of realism provides a surgical training method that was previously impossible.

[0043] Referring now to Figure 15, a stencil 116 according to the present invention is shown. The stencil 116 may also be referred to as a plate, screen, mask or other similar article, which will be used without distinction throughout this specification to describe the same stencil 116. The stencil 116 has a top surface 118, which is located opposite the bottom surface 120 and interconnected with it. A number of holes 122 are formed in the stencil 116. The holes 122 extend through the top surface 118 to the bottom surface 120. The holes 122 are formed in a pattern, as shown in Figure 15. The pattern in Figure 15 is uniform throughout the stencil 116. The resolution of the stencil 116 is defined as the number of lines per inch (2.54 cm) or the number of dots per inch measured parallel to the angle of the stencil located in the plane of the stencil 116, for example, the zero angle which is considered to be equal to 9 o'clock on a clock drawn on the surface of the stencil, or any other angle.

[0044] The holes 122 shown in Figure 15 are circular in shape. However, the present invention is not limited thereto, and the holes 122 can be formed to have any desired shape. For example, the holes 122 may be round, elliptical, or square. For example, Figure 16 shows a stencil 116 having multiple holes 122 that are shaped like small curves. A repeating pattern of curved holes 122 is evenly distributed throughout the stencil 116, and these curved holes mimic the vascular system or other anatomically accurate visual representations seen in actual surgery. The pattern of holes 122 shown in Figure 17 is limited to only a portion of the stencil 116, for example, formed in the shape of a circle made up of a circular hole located in the center of the stencil 116, with three additional circular holes 122 located in the center of the larger circle. The pattern and number of holes 122 are formed for a specific purpose in forming a simulated tissue structure. For example, the holes 122 may be shaped to represent an anatomical viewpoint of interest. The illustrative anatomical viewpoint may include the vascular system, such as capillaries, and therefore the stencil 116 has several small curves that are randomly formed or patterned on the stencil 116. Such a stencil 116 can be used to measure blue or red colored silicone to provide a functional layer having, for example, a representative structure and color. Another embodiment may include a stencil 116 configured to impart muscle features. In this case, the holes 122 of the stencil 116 are preferably elongated, straight, substantially parallel to each other, and angled to represent muscle lines found in muscle layers. Such a stencil 116 can be employed to measure a layer of red silicone or hydrogel material, or multiple layers can be formed by stacking hydrogel layers measured via the stencil 116 and colored silicone layers 115 directly applied on the hydrogel layers, and the multiple layers can be separated by cured silicone layers between the two functional layers formed by the stencil 116. As a variation, a layer of silicone is formed via stencil 116 and sandwiched between one or more hydrogel layers.The functional layer made of hydrogel is configured to conduct electricity to mimic electrosurgery on the simulated tissue structure 110. A stencil 116 having a complex form of holes 122 of various shapes, patterns, and arrangements is shown in Figure 18. In Figure 18, a uniform pattern of circular holes 122 is visible in the upper right corner of the stencil 116, and a curved arrangement of small, circular holes 122 is formed in the lower left corner of the stencil 116, with these holes separated by the curves formed by the circular holes 122. The custom stencil 116 is formed to create a specific viewpoint or feature in one layer of a simulated tissue structure consisting of multiple layers. Alternatively, multiple stencils can be used at the same interface to create a custom arrangement of characteristics for that interface. Such characteristics include, but are not limited to, material properties, adhesion quality, color, and shape. The stencil 116 preferably has a thickness selected for the type, quantity, and desired thickness of the resulting stencil layer.

[0045] Referring next to Figure 19, a first base layer 112 is shown, having a top surface 124, which is interconnected with a bottom surface 126 and positioned opposite to this bottom surface. The top surface 124 is substantially flat and parallel to the substantially flat bottom surface 126. The stencil 116 is shown spaced apart from the first layer 112 and oriented so that the bottom surface 120 of the stencil 116 faces the top surface 124 of the first layer 112. The stencil 116 is round and has a plurality of holes 122 formed in a uniform pattern across the stencil 116. The shape and pattern of the holes 122 are illustrative and not limiting to the present invention. In the next step shown in Figure 20, the stencil 116 is placed on the first sheet or first layer 112 so that the bottom surface 120 of the stencil 116 contacts or faces the top surface 124 of the first layer 112. A mold release agent, resist, grease, powder, lubricant, or other substance is applied to the stencil 116 so that this substance is applied to the top surface 124 of the first layer 112 through the holes 122. The stencil 116 is removed, and thereafter, the applied substance or the pattern of the first stencil layer 115a remains on the first layer 112, having the same pattern and shape as the holes 122 on the stencil 116, as shown in Figure 21. In this embodiment, the first stencil layer 115a includes a plurality of patterned dots. As a variation, instead of a mold release agent, an adhesive, such as glue or silicone or other adhesive, may be used, and such adhesive may be applied to the first layer 112 via the stencil 116. Furthermore, the substance applied via the stencil 116 may be a conductive material, such as a hydrogel or a conductive material / filament. The material may also preferably contain fibers or a mesh to improve the suture-holding ability of the layer. The first layer 112 is a cured layer of silicone, such as platinum-curable room-temperature vulcanized silicone (PCRTVS) rubber. The first layer 112 may be made of KRATON, any elastomer or hydrogel or other conductive material or polymer material. The first stencil layer 115a is cured either before or after the removal of the stencil 116.Figure 21 shows at least a portion of the simulated tissue structure 110 with the stencil 116 removed from the structure. Any of the material applied by the stencil 116 may contain a color suitable for a visual effect that is desirable to be created by employing an anatomical structure to be imitated or a combination of transparency and color. In one aspect of the present invention, the structure in Figure 21 is a simulated tissue structure in its completed state. In another aspect of the present invention, one or more additional stencil layers 115 of the same or different material may be applied either directly over the previously applied stencil layer 115a or offset from the previously applied stencil layer 115a through the same or different stencil 116.

[0046] The next step in the method for forming a simulated tissue structure according to the present invention is shown in Figure 22, where a combination of a first base layer 112 and one or more stencil layers 115a, for example the combination shown in Figure 21, is placed alongside a second base layer 114. In one embodiment, the second base layer 114 is an uncured silicone, PCRTVS, which is applied to the top surface 124 of the first stencil layer 115a and the first layer 112 and cured thereafter, thereby forming a sandwich containing the first layer 112 and the second layer 114, with one or more first stencil layers 115a placed between the first and second layers. Still referring to Figure 22, the second layer 114 has a top surface 130 interconnected with a bottom surface 132. If the first stencil layer 115a has adhesive properties, the first layer 112 and the second layer 114 will have strong adhesion points at the location where the patterned first stencil layer 115a is placed. If the first stencil layer 115a contains a material that can function as a resist or release agent, the first layer 112 and the second layer 114 will have points where the first layer 112 and the second layer 114 are easily and readily separated at the location where the patterned stencil layer 15a is placed. That is, the bottom surface 132 of the second layer 114 is removable or detachable from the top surface 124 of the first layer 112 at the location where the first stencil layer 115a is placed. The resulting simulated structural body 110 can be considered complete at this stage of production, or it can be created or advanced into a multilayer structure by adopting the completed sandwich state shown in Figure 22 and arranging it in a parallel and flat manner alongside the stencil 116 as shown in Figure 23. The stencil 116 may be the same stencil 116 used alongside the first layer 112, or it may be a different stencil 116. If the same stencil 116 is used, it may be placed directly above the previous stencil 116, or it may be placed offset from this position, or it may be angled toward the previous stencil 116.The second stencil 116 may have holes 122 with a different pattern than those of the first stencil 116, and these holes 122 may have a different shape and dimensions from the pattern, shape and dimensions of the first stencil 116. The bottom surface 120 of the stencil 116 is positioned adjacent to or in contact with the second layer 114 such that the bottom surface 120 of the stencil 116 faces the outer surface of the second layer 114. In one embodiment, the first stencil layer 115a is visible through the second layer 114 because the second layer 114 is transparent or translucent. With the stencil 116 in place, a mold release agent, resist, grease, powder, lubricant, or other substance is applied to the stencil 116 so that the substance is applied to the top surface 130 of the second layer 114 through the holes 122 of the second stencil 116. The stencil 116 is removed, leaving behind the material applied to the second layer 114 or the pattern of the second stencil layer 115b, as shown in Figure 24. In this embodiment, the second stencil layer 115b includes a plurality of patterned dots offset from the first pattern of dots as a result of printing the material through the first stencil 116. As a variation, instead of a release agent, an adhesive, such as glue or silicone or other adhesive, may be used, and such adhesive may be applied to the second layer 114 via the stencil 116. Furthermore, the material applied via the stencil 116 may be a conductive material, such as a hydrogel or a material having conductive filaments. This material may also preferably include fibers or a mesh. The desired interface properties are applied to the second layer 114 via the stencil 116 for the interface between the second layer 114 and the third layer 134.

[0047] Figure 25 shows the next steps in the method for manufacturing a simulated tissue structure according to the present invention, in which the combination of the first base layer 112, the first stencil layer 115a, the second base layer 114, and the second stencil layer 115b is arranged in a juxtaposition relationship with the third base layer 134. In one embodiment, the third base layer 134 is PCRTVS, which is an uncured silicone that is applied to the top surface 130 of the second stencil layer 115b and the second base layer 114 and cured. The stencil 116 is removed so that the first stencil layer 115a is positioned between the first layer 112 and the second layer 114, forming a sandwich of the first layer 112, the second layer 114, and the third layer 134, with the second stencil layer 115b positioned between the second layer 114 and the third layer 134. The third layer 134 has a top surface 136 that is interconnected with the bottom surface 138 to determine a substantially uniform thickness. If the second stencil layer 115b contains an adhesive, the second layer 114 and the third layer 134 will have strong adhesion points at the placement locations of the patterned second stencil layer 115b. If the second stencil layer 115b contains a resist or release agent, the second layer 114 and the third layer 134 will have points where the second layer 114 and the third layer 134 can be easily and readily separated at the placement locations of the material dots of the second stencil layer 115b. That is, the bottom surface 138 of the third layer 134 is removable or detachable from the top surface 130 of the second layer 114. Thus, a custom arrangement of interface characteristics between multiple layers is created. The resulting simulated tissue structure 110 can be considered complete at this stage of production, or it can be created or advanced into a multilayer structure by adopting the completed sandwich state in Figure 25 and arranging it juxtaposed with another stencil 116 as shown in Figure 26 to form a third stencil layer 115c. The stencil layers 115a and 115b appear as the sandwich structure shown in Figure 26 because the second layer 114 and the third layer 134 are transparent or translucent silicone layers in one form.

[0048] Still referring to Figure 26, the stencil 116 is placed on the third sheet or third layer 134 so that the bottom surface 120 of the stencil 116 contacts or faces the top surface 136 of the third layer 134. A mold release agent, resist, grease, powder, lubricant, or other substance is applied to the stencil 116 so that this substance is applied to the top surface 124 of the third layer 134 through the holes 122. The stencil 116 is removed, leaving behind the substance applied on the third layer 134 or the pattern of the third stencil layer 115c, as shown in Figure 26. In this embodiment, the third stencil layer 115c has multiple patterned dots that are slightly offset from the first stencil layer 115a and the second stencil layer 115b. As a variation, instead of a release agent, an adhesive, such as glue or silicone or other adhesive, may be used to apply such adhesive to the third layer 134 via the stencil 116. Furthermore, the material applied via the stencil 116 may be a conductive material, such as a hydrogel or a material having conductive filaments. The material may also contain fibers or mesh. The third layer 134 is a cured layer of silicone, such as platinum-curable room-temperature vulcanized silicone (PCRTVS) rubber. The third layer 134 may be made of KRATON, any elastomer or hydrogel or other conductive material or polymer material. The third stencil layer 115c is cured either before or after the removal of the stencil 116. Figure 26 shows at least a portion of the simulated tissue structure 110 with the stencil 116 removed from the structure and the fourth base layer 140 applied. Any of the substances applied by the stencil 116 may contain a color, shape, and structure suitable for the desired training and evaluation purposes for the anatomical structure or simulated tissue structure 110 that is to be imitated. In one aspect of the present invention, the structure in Figure 26 is a simulated tissue structure in its completed state.In another aspect of the present invention, it is preferable that one or more additional stencil layers 115 of the same or different materials or functional properties be applied through the same or different stencils 116 either directly above or offset from the previously applied stencil layer 115c. As shown in Figure 26, interesting patterns of color and / or other material properties are created, which are incorporated into the simulated tissue structure 110, and these are enhanced by the transparency of the intermediate layer. The color patterns created by the different shapes of the stencil holes 122 are designed to mimic real tissue coloring, including tumor coloring, which may appear darker. Furthermore, the simulated tumor locations can be removed like real tumors when practicing procedures using the simulated tissue structure 110 of the present invention, for example, by coloring them in one or more dark colors, and by the surgical technique at the placement of black, brown or dark red dots and the mold release performance at the same or surrounding locations of the dots. The placement or pattern of the release / resist or adhesive is predetermined and, in one form, arranged to teach the surgeon the optimal excision route to be taken with a scalpel or other instrument.

[0049] Still referring to Figure 26, the sandwich structure of the first layer 112, the second layer 114, the first stencil layer 115a positioned between the first and second layers, the third layer 134, and the third stencil layer 115c positioned on the top surface 136 of the third layer 134 is positioned alongside the fourth layer 140. The fourth layer 140 is preferably a pre-formed and pre-cured sheet of platinum-curable room-temperature vulcanizable silicone (PCRTVS) positioned on the top surface 136 of the third layer 134 to sandwich the third stencil layer 115c. As a variation, a fourth layer 140 of uncured PCRTVS is poured onto the sandwich structure and cured depending on the material of the third stencil layer 115c, either strongly adhering to the dot placement locations of the third stencil layer 115c when an adhesive is provided, or easily separating at the dot placement locations of the third stencil layer 115c when a release agent or resist is used. The simulated tissue structure 110 shown in Figures 26 and 27 shows a final structure in one embodiment of the present invention, comprising a first layer 112, a second layer 114, a third layer 134, and a fourth layer 140, with the first stencil layer 115a positioned between the first layer 112 and the second layer 114, the second stencil layer 115b positioned between the second layer 114 and the third layer 134, and the third stencil layer 115c positioned between the third layer 134 and the fourth layer 140. In one embodiment, layers 112, 114, 134, and 140 are transparent so that the dots of stencil layers 115a, 115b, and 115c are at least partially visible through structure 110. It is preferable that each of the stencil layers 115a, 115b, and 115c be formed in a different color from each other. For example, the first stencil layer 115a is green, the second stencil layer 115b is blue, and the third stencil layer 115c is red. As a result, a moiré pattern of the RGB color space and shape is obtained. In another embodiment, in the construct shown in Figures 26 and 27, the topmost layer, which is the fourth layer 140, is colored flesh-colored or tan to represent skin.The layering of the simulated tissue structure 110 is preferably followed by the addition of a stencil layer 115 and a base layer as described, thereby creating a sandwich stack of responsive compartments and interfaces located within the structure.

[0050] Referring now to Figure 28, another form of the stencil 116 is shown, having multiple holes 122 configured to mimic the arteries of the human retinointestinal omentum. The stencil 116 in Figure 28 is used to place red-colored silicone through the multiple holes 122 to form the distinctive shape of the retinointestinal arteries onto a first base layer (not shown). A second base layer is often used to sandwich the retinointestinal artery structure between the first base layer and the stencil, thereby completing the simulated retinointestinal omentum. The stencil 116 is not limited to forming the retinointestinal artery structure and can be used with unique holes 122 to mimic the structure or distinctive shape of a specific organ / tissue to obtain the desired result.

[0051] Referring next to Figure 29, another embodiment of the first stencil 116a is shown juxtaposed with the first base layer 112. The first base layer 112 is a flattened sheet of silicone as described above. The first stencil 116a has at least one hole 122. In particular, the first stencil 116a has a first set of holes 122, including a circular hole 122 and an elongated hole 122a. Each elongated hole 122a has a first end 152 and a second end 154 that define the shape to which the first stencil layer 115a, made of, for example, silicone, adhesive, release agent, hydrogel, conductive material, fiberfill, mesh, filament or any other desired material, is attached. Figure 30 shows the first stencil layer 115a attached to the top surface of the first base layer 112. The holes 122a of stencil 116a form a first stencil layer 115a on the first base layer 112 having elongated structures and dots, each elongated structure having a first end 152a and a second end 154a. The simulated tissue structure is made with a second base layer 114 covering the first stencil layer 115a and the first base layer 112, as shown in Figure 31. The simulated tissue structure is further made with a second stencil 116b attached, as shown in Figure 32. The second stencil 116b has a plurality of holes 122. In particular, the second stencil 116b has a first set of holes 122, including circular holes 122 and elongated holes 122b. Each elongated hole 122b has a first end 156 and a second end 158 that define the shape upon which a second stencil layer 115b, made of, for example, silicone, adhesive, release agent, hydrogel, conductive material, fiberfill, mesh, filament, or any other desired material, is attached. Figure 33 shows the second stencil layer 115b attached to the top surface of the second base layer 114. The holes 122b of the stencil 116b form the second stencil layer 115b having elongated structures and dots on the second base layer 114, with each elongated structure having a first end 156a and a second end 158a. Figure 34 shows the third base layer 134 attached above the second stencil layer 115b and the second base layer 114. Figure 35 shows the third stencil 116c juxtaposed with the components of Figure 34.The third stencil 116c has a plurality of holes 122c containing elongated structures, each having a first end 160 and a second end 162. The third stencil 116c is placed on top of the third base layer 134 to print the third stencil layer 115c, as shown in Figure 36. The third stencil layer 115c has a plurality of dots and elongated structures, each having a first end 160a and a second end 160b. Next, the fourth base layer 140 is superimposed on the third stencil layer 115c and the third base layer 134, as shown in Figure 37, to complete the structure 110. The perspective view of the simulated structure 110 in Figure 38 shows how the plurality of dots formed by the stencil layers 115a, 115b, and 115c create a functional pattern of variable adhesion along the interface. Furthermore, Figure 38 shows how multiple printed dots in the stencil layer can create color patterns, especially when any one or more of the base layers 112, 114, 134, and 140 are transparent. The resulting unique color patterns create a realistic depiction that makes it difficult to pinpoint the location of the elongated structures in the layers, which may represent anatomical features such as the vascular system, arteries, and tubes. Stencils 116a, 116b, and 116c are configured to be used sequentially to print anatomical structures on each base layer, so that the anatomical structures not only spread within the interface printed in the X-Y plane, but also appear to spread in the X-Y plane of the entire simulated tissue structure when viewed along the Z-axis perpendicular to the X-Y plane of the simulated tissue structure, as can be seen in Figure 39. In one form, the anatomical structures do not intersect with the base layers but simply overlap at their endpoints, thereby giving the appearance of continuous anatomical structures.For example, the first stencil 116a is used to print at least one anatomical structure having a proximal end 152a and a distal end 154a onto the first base layer 112, and the second stencil 116b is used to print the continuity of at least one anatomical structure onto the second base layer 114 by printing the proximal end 152a adjacent to or overlapping with the distal end 154a of the previously printed anatomical structure onto the second base layer 114, giving the appearance of a continuity of anatomical structures traversing the interface when viewed along the Z axis. Furthermore, the third stencil 116c is used to print the continuity of at least one anatomical structure onto the third base layer 134 by printing the proximal end 160a adjacent to or overlapping with the distal end 158a of the previously printed anatomical structure onto the third base layer 134, giving the appearance of a continuity of anatomical structures along the Z axis. In another configuration, the base layers 114a,134a are provided with holes where overlapping edges of anatomical structures exist, thereby eliminating discontinuities across the Z-axis for wet silicone or other material used during printing when the anatomical structure is printed, passing through the holes in the base layers 114a,134a. When hydrogel material or other conductive or non-conductive material is used during printing of the anatomical structure, a conductive / non-conductive fluid circuit may be printed, which may then be connected to ground and a power source for simulated electrosurgery or other operations.

[0052] The simulated structural body 110 formed according to the present invention advantageously introduces functional layers printed using stencils between non-functional substrates or support layers. During the printing of the functional layers, the stencil is used to pattern the material onto the substrate, and then the stencil is removed. Each functional layer can serve one or more functional purposes. Furthermore, multiple functional layers can be printed continuously between two adjacent substrates, or different functional layers can be printed at different interface locations. As described above, the stencil layers can serve the function of providing mechanical interaction between two substrates. For example, the location of adhesive and / or release agents, and the degree of adhesive and / or release, can be provided by functional layers printed in a specific shape, pattern, to provide the location of mechanical interaction and the form of printed material, whether or not the release agent / adhesive or other substance provides the form and strength of mechanical properties to create customized properties for that particular interface. Areas of weak mechanical connections can be provided by printing release agent / resist material, etc. Strong mechanical attachment areas between base layers can be provided by printing uncured silicone onto a base layer of cured silicone, or by printing adhesives, glues, etc. Another purpose achieved by the functional layer is to provide conductive pathways to create a simulated tissue structure suitable for practicing electrosurgery, for example. In such cases, hydrogel is printed onto the base layer via a stencil. It is preferable that the hydrogel's fluid circuits interconnect the dots or other patterns of the functional layer, and that the functional layer be patterned to further connect to ground or power. Creating circuits can be done by providing non-conductive areas / pathways, along with printing conductive materials other than hydrogel, such as conductive filaments, to provide pathways for conductivity. Another functional purpose that the functional layer can provide is sutureability. In such cases, the stencil is used to reinforce areas for holding sutures by laying silicone together with mesh, fibers, etc. Another function of the stencil layer is preferably release.For example, polyfill material can be used and applied via a stencil onto a dry or wet silicone substrate to embed the polyfill material between the substrates at specific locations, and then a functional interface can be created that is easily peeled off or separated by adhering an adjacent wet layer of silicone and cutting the polyfill fibers. Functional layers can help provide realistic coloring to the layer, or, when used in conjunction with a transparent or translucent substrate, the color pattern can overlap with functional layers of other colors to create an overall effect. Also, as described above, functional layers can be used to position anatomical structures between and / or across the substrates. Unique shapes representing various anatomical structures can be formed using stencils, and such formations include, but are not limited to, printing the shape and color of Tort's fascia, mesh, anatomical landmarks / structures, etc. In another embodiment of the present invention, the stencil is not removed from the structure and remains to form an integrated part of the simulated tissue structure. For example, the stencil is often shaped to represent an anatomical bone structure or cartilage and is positioned between two substrates to which adjacent substrates are to be deposited in an uncured state, thereby interlocking with the adjacent substrates to embed the stencil. In another form, the stencil is designed and configured not to represent an anatomical structure in its left-to-resolve state, but to impart structural rigidity to the resulting structure. In yet another form, the stencil is not employed to deposit an intermediate functional layer between two substrates, but rather serves to simply allow the deposition of adjacent uncured silicone substrates through the holes in the stencil so that they can be attached to adjacent substrates within a selected area defined by the stencil openings.

[0053] The simulated tissue structure 110 of the present invention is particularly suitable for laparoscopic procedures, and such a simulated tissue structure can be used in a laparoscopic training device. However, the present invention is not limited thereto, and the simulated tissue structure 110 of the present invention can be used independently to train first-entry surgical procedures equally effectively.

[0054] As can be understood, various modifications are possible to the embodiments of artificial tissue simulation and the methods of manufacturing these embodiments disclosed herein. Therefore, the above description should not be construed as limiting the invention, but rather as merely illustrative examples of preferred embodiments. Those skilled in the art will likely conceive of other modifications that fall within the scope and spirit of the invention.

Claims

1. It is a simulated organizational structure, A simulated anatomical structure comprising a first material having a proximal and distal end located within a thin shell of a second material, the thin shell having a proximal and distal end, and the simulated anatomical structure being attached to the second material, The simulated anatomical structure is a simulated tissue structure formed and configured to be detachably connected via an adapter to the interlock portion of a mandrel or to the distal end of the mandrel.

2. The simulated tissue structure according to claim 1, wherein the inner surface of the simulated anatomical structure has a cross section having dimensions and configuration such that the interlock portion of the mandrel is fitted tightly into the lumen.

3. The simulated tissue structure according to claim 2, wherein the cross-sectional shape of the lumen is one of a hexagon, ellipse, square, triangular, pentagonal, slotted, or elongated shape.

4. The simulated tissue structure according to claim 1, wherein the proximal portion of the simulated anatomical structure is formed with a male boss, and the adapter has a cross section having dimensions and configuration such that it receives the male boss in a tight fit.

5. The simulated tissue structure according to claim 4, wherein the cross-sectional shape of the male boss is one of hexagonal, elliptical, square, triangular, pentagonal, slotted, or elongated shapes.

6. The simulated tissue structure according to any one of claims 1 to 5, wherein the first material is a foam and the second material is silicone.

7. The simulated tissue structure according to any one of claims 1 to 6, wherein the second material extends proximal beyond the proximal end of the simulated anatomical structure.

8. The simulated tissue structure according to claim 7, wherein the second material extends distally beyond the distal end of the simulated anatomical structure.

9. The simulated tissue structure according to any one of claims 1 to 6, wherein the second material extends distally beyond the distal end of the simulated anatomical structure.

10. The simulated tissue structure according to any one of claims 1 to 9, further comprising a simulated cyst located between the simulated anatomical structure and the second material.

11. The simulated tissue structure according to claim 10, wherein the simulated anatomical structure further comprises a dimple having a size and configuration for seating the simulated cyst, or the simulated cyst is formed integrally with the simulated anatomical structure.

12. The simulated tissue structure according to any one of claims 1 to 11, wherein the simulated anatomical structure has a bulbous outer surface, and the thin shell of the second material has an inner surface configured to match the outer surface of the simulated anatomical structure.

13. The simulated tissue structure according to claim 2 or 3, wherein the lumen is configured to extend from the proximal opening of the proximal end into the simulated anatomical structure.

14. The simulated tissue structure according to claim 13, wherein the lumen is configured to extend between the proximal opening at the proximal end and the distal opening at the distal end of the simulated anatomical structure.

15. The simulated tissue structure according to claim 4 or 5, wherein the mandrel is an elongated cylindrical rod having a circular cross-section, and the adapter is configured to be further connected to the distal end of the mandrel.

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