Simulated dissectible tissue

Abstract

To provide a simulated dissectible tissue for surgical training.SOLUTION: A simulated tissue comprises a silicone gel layer encapsulated within a silicone shell. A simulated anatomical structure is embedded together with the silicone gel layer within a sealed shell. The silicone shell as well as the silicone gel layer may include a deadening agent. A simulated dissectible tissue 47 may be formed into a specific tissue or organ model for practicing surgical skills. A user practices incising through the outer layer and then separating the shell layer along a dissection plane defined by the silicone gel layer to gain visibility of the embedded simulated anatomical structures. The silicone gel layer simulates dissectible tissue and has glossy and elastic properties that provide a realistic dissectible tissue layer for emulating skeletonization of the simulated anatomical structures contained therein.SELECTED DRAWING: Figure 7C

Description

[Technical field]

[0001] The present invention relates to surgical training tools, and in particular to simulated tissue structures and models for teaching and practicing surgical procedures.

[0002] Description of Related Applications This application claims priority to and the benefit of U.S. Provisional Patent Application No. 61 / 970,436, filed March 26, 2014 (title: Right colon model), which is incorporated herein by reference in its entirety. [Background technology]

[0003] Laparoscopic colectomy involves the resection of the intestine at various locations. Depending on where the intestine is located, the colectomy is called a right hemicolectomy, a left hemicolectomy, a sigmoidostomy, or a total colectomy. A right hemicolectomy is the removal of the entire ascending colon, including a portion of the transverse colon, and is the most common of the colectomy procedures. The key step in the right hemicolectomy procedure is to be able to identify important anatomical landmarks and vasculature to transect (cut laterally) the appropriate vessels and attachments to allow mobilization of the colon. The surgeon's first step in this procedure is to identify and transect the ileocolic vessels. With the patient in the Trendelenburg position with the right side facing upwards, the ileocolic vessels are retracted. This position helps to remove the omentum and small intestine. The ileocolic vessels are typically located adjacent to the duodenum, and are encapsulated within the mesentery, which is made up of two peritoneal layers. During this step, the surgeon uses the duodenum as a structural landmark in locating the ileocolic vessels. When transecting the ileocolic vessels, either a medial-lateral or a lateral-medial incision of the mesenteric layer may be performed. This incision is performed by blunt dissection using laparoscopic tools or energy compatible instruments that can cut and seal small vasculature or vasculature and lymph nodes encapsulated within the mesenteric layer. For a medial-lateral incision, an anterior movement of the duodenum and Gerota's fascia is made towards the mesenteric root, which is attached to the cecum and ileum. If the surgeon moves lateral-medial, the incision is made at the ileocecal junction and moved medially, again leaving the duodenum and Gerota's fascia anterior. Once the cecum and ileum have been mobilized, the surgeon elevates the line of Tolt to reach the right flexure of the colon. The line of Tolt is an avascular plane that is connected to the abdominal sidewall via lateral or external attachments. The surgeon typically uses energy compatible laparoscopic scissors or other laparoscopic instruments to dissect the attachments and the line of Tolt. During dissection of the line of Tolt, the attachments along the right flexure are removed in order to allow for external mobilization and transection of the intestine. Upon transection of the intestine, the surgeon performs an external anastomosis, thereby reconnecting the remaining intestine.

[0004] Since there are several procedural steps for a right hemicolectomy, it is important to ensure that surgeons have a way to learn and practice this surgical procedure. The model needs to be anatomically accurate and includes important landmarks and / or vasculature required for a right hemicolectomy procedure. The model should be compatible with any variations of procedural steps. As an example, it should allow either a medial-lateral or a lateral-medial incision to be performed on the model. Additionally, the model should simulate the feedback that the surgeon observes during the procedure. As an example, when an incision is made in the mesenteric layer, the difference in navigating the mesenteric layer to the larger blood vessels should be evident. The blood vessels should be able to be grasped, cut, and clipped. Although there are several procedural steps, the majority of the procedure involves mobilizing the intestines through various incision techniques, and therefore developing an accurate incision model is crucial to the simulation. The organs in the model should be simulated such that they can be moved and manipulated as they would be located in the body. In addition, the organs on the model should be attached to the model in a way that allows the organs on the model to be moved in the correct direction when the model is positioned in Trendelenburg or reverse Trendelenburg positioning. There is a need for an anatomical model that solves these problems.

[0005] Furthermore, surgical residents as well as practicing surgeons undergo extensive training before they are qualified to operate on human patients. During the training, various aspects of surgery are taught, which may include training to develop specific skills, practice specific surgical procedures, or practice with certain surgical instruments. There is a need for an integrated simulated model that facilitates training for surgeons. In particular, there is a need for simulated tissue that closely resembles the response of human tissue being dissected. The ability to make dissections between planes or to skeletonize the vasculature from the surrounding anatomical structures are skills found in surgical procedures. Particularly when laparoscopic procedures are performed, the manipulation of instruments to make the dissections is a skill that can be learned, which allows for an atraumatic procedure that minimizes trauma. The present invention relates to such simulated tissue. Summary of the Invention

[0006] According to one aspect of the present invention, there is provided a dissectable simulated tissue for surgical training. The dissectable simulated tissue has a first layer made of silicone and having an inner surface and an outer surface, a thickness defined between the inner surface and the outer surface. The dissectable simulated tissue has a second layer made of silicone and having an inner surface and an outer surface, a thickness defined between the inner surface and the outer surface. The dissectable simulated tissue has a third layer including a silicone gel disposed between the first layer and the second layer. The silicone gel is sealed by the first layer and the second layer. The first and second layers are dissectable and the third layer resiliently adheres the first layer and the second layer to one another such that the first and second layers are separable by a blunt instrument.

[0007] According to another aspect of the present invention, a dissectable simulated tissue for surgical training is provided, the dissectable simulated tissue having an outer shell made of silicone and configured to define an internal cavity, a filler is disposed within the internal cavity and sealed, the encapsulated filler comprises silicone gel, and the outer shell is separable at the location of the filler to mimic surgical skeletonization.

[0008] According to another aspect of the present invention, there is provided a method for producing a dissectable simulated tissue for surgical training, the method comprising the steps of providing a first layer of silicone, curing the first layer, providing a mold with a central cavity, placing the first silicone layer on the mold such that the first layer covers the central cavity, preparing a silicone gel, applying uncured silicone gel onto the first layer, providing a second layer of silicone, placing the second layer on the silicone gel and the first layer, curing the silicone gel, and curing the second layer.

[0009] According to another aspect of the invention, there is provided a method of making a dissectable simulated tissue having one or more outer layers encapsulating an inner layer. The method includes the step of selecting a material for the outer layer. The step of selecting a material for the outer layer includes the step of selecting one of a silicone and a mixture of silicone and deadener. The method includes the step of selecting a material for the inner layer. The step of selecting a material for the inner layer includes the step of selecting one of a silicone gel and a mixture of silicone gel and deadener. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a top perspective view of a laparoscopic training device. [Diagram 2] FIG. 2 is a plan view of the right colon model of the present invention. [Diagram 3] FIG. 1 is a plan view of a right colon model with the omentum layer pulled back in accordance with the present invention. [Figure 4] FIG. 2 is a plan view of the large intestine of the right colon model of the present invention. [Diagram 5] FIG. 2 is a plan view of the aorta of the right colon model of the present invention. [Figure 6] FIG. 2 is a plan view of a simulated tissue structure of the present invention, for example, the mesenteric layer. [Figure 7A]1 is a schematic diagram illustrating steps in the manufacturing process of a simulated tissue structure, eg, a mesentery layer, of the present invention. [Figure 7B] 1 is a schematic diagram illustrating steps in the manufacturing process of a simulated tissue structure, eg, a mesentery layer, of the present invention. [Figure 7C] 1 is a schematic diagram illustrating steps in the manufacturing process of a simulated tissue structure, eg, a mesentery layer, of the present invention. [Figure 7D] 1 is a schematic diagram illustrating steps in the manufacturing process of a simulated tissue structure, eg, a mesentery layer, of the present invention. [Figure 7E] 1 is a schematic diagram illustrating steps in the manufacturing process of a simulated tissue structure, eg, a mesentery layer, of the present invention. [Figure 8A] FIG. 1 shows a list of compositional variations in the outer layer of a simulated tissue structure of the present invention, for example the mesenteric layer. [Figure 8B] FIG. 1 shows a list of compositional variations in the middle or inner layer of a simulated tissue structure of the present invention, such as the mesenteric layer. [Figure 9A] 1 is a flow diagram of compositional variations of simulated tissue structures, such as the mesenteric layer, of the present invention. [Figure 9B] 1 is a flow diagram of compositional variations of simulated tissue structures, such as the mesenteric layer, of the present invention. [Figure 10A] FIG. 2 is a plan view of a first layer of the dissectable simulated tissue of the present invention. [Figure 10B] FIG. 2 is a plan view of a mold and template for producing the dissectable simulated tissue of the present invention. [Figure 10C] FIG. 2 is a plan view of a first layer of dissectable simulated tissue on top of a mold and template of the present invention. [Figure 10D] FIG. 1 is a plan view of a simulated vasculature and a simulated tumor on top of the first layer, template and mold of the present invention. [Figure 10E] FIG. 2 is a top view of the simulated vasculature, simulated tumor, first layer, template, and second layer of gel on top of the mold of the present invention. [Figure 10F] FIG. 2 is a top view of a second layer of gel of the present invention, a simulated vasculature, a simulated tumor, a first layer, a template, and a third layer on top of a mold. [Figure 10G] FIG. 2 is a top perspective view of a dissectable simulated tissue model attached to a peg of the simulated tissue platform of the present invention. [Figure 10H] FIG. 2 is a plan view of a model of dissectable simulated tissue attached to a peg of the simulated tissue platform of the present invention. [Figure 11] FIG. 2 is a top plan view of a dissectable simulated tissue with an incision made in the outer layer exposing the inner gel layer in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An organ tray model of one or more simulated organs and tissues is ideal for training and practicing laparoscopic procedures and techniques when placed inside a simulated laparoscopic training device, such as the SIMSEI Laparoscopic Training System manufactured by Applied Medical Resources Corporation of California. The laparoscopic training device 10 is shown in FIG. 1. The laparoscopic training device 10 is described in co-pending U.S. patent application Ser. No. 13 / 248,449, entitled "Portable laparoscopic trainer," filed Sep. 29, 2011 by Pravong et al., assigned to Applied Medical Resources Corporation, and published as U.S. Patent Application Publication No. 2012 / 0082970, which is incorporated by reference in its entirety. The laparoscopic training device 10 includes a top cover 12 connected to a base 14 by a pair of legs 16 that separate the top cover 12 from the base 14. The laparoscopic training device 10 is configured to simulate a patient's torso, e.g., abdominal region. The top cover 12 represents the anterior aspect of the patient, and the space defined between the top cover 12 and the base 14 represents the patient's interior or body cavity 18 in which the organs are located. The laparoscopic training device 10 is a useful tool for teaching, practicing, and demonstrating various surgical procedures and their associated instruments in a simulated patient environment. Surgical instruments are inserted into the cavity 18 through pre-drilled holes 20 in the top cover 12. These pre-drilled holes 20 may have seals simulating trocars or may have simulated tissue simulating the skin and abdominal wall portions of the patient. A variety of tools and methods can be used to penetrate the top cover 12, thereby allowing full-scale procedures to be performed on a model organ disposed between the top cover 12 and the base 14, such as the right colon model of the present invention.Once placed within the cavity 18 of the training device 10, the organ model is generally obscured from the user's view, and the user can then laparoscopically practice the surgical procedure by indirectly observing the surgical site via a video feed displayed on the video monitor 22.

[0012] A video display monitor 22 hinged to the top cover 12 is shown in an open orientation in FIG. 1. The video monitor 22 can be coupled to a variety of vision systems for transmitting images to the monitor 22. For example, a laparoscope inserted through a webcam provided in one of the pre-formed holes 20 or cavity and used to view the simulated procedure can be coupled to the video monitor 22 and / or a mobile computing device to provide images to the user. In another variation, the top cover 12 does not include a video display 22 but has a means for supporting a laptop computer, mobile digital device or tablet and connecting it to the training device 10 by wire or wirelessly.

[0013] When assembled, the top cover 12 is placed directly over the base 14 with the legs 16 disposed substantially at the periphery and interconnected between the top cover 12 and the base 14. The top cover 12 and the base 14 are of substantially the same shape and size and have substantially the same peripheral contours. The exerciser 10 does not include side walls, but the legs 16 partially hide the interior cavity from view of the open-ended exerciser 10. The laparoscopic exerciser 10 has a top cover 12 angled relative to the base 14. The legs 16 are configured to allow the angle of the top cover 12 relative to the base 14 to be adjusted. FIG. 1 shows the exerciser 10 adjusted to an angle of about 30-45° relative to the base 14. The inclination of the exerciser 10 advantageously simulates a patient in a Trendelenburg or reverse Trendelenburg position. In the Trendelenburg position, the patient's body is tilted so that the patient is lying flat on his back with the feet higher than the heart or vice versa. The Trendelenburg position allows good access to the pelvic organs when gravity pulls the intestines away from the pelvis, thereby preventing the intestines from entering the pelvic surgical field and providing a large working space in the abdominal cavity where the surgeon can easily manipulate the organs. The selected angular position of the top cover 12 is locked by indicating thumb screws on the legs 16. The angle of the top cover 12 of the training device 10 relative to the base 14 or the angle of the top cover 12 relative to a horizontal plane, e.g., a table top, is particularly advantageous for training and practicing right hemicolectomy with the colon model of the present invention inserted into the cavity 18 of the training device 10.

[0014] 2, a right colon model 26 of the present invention is shown that is particularly suited for training and practicing procedures in a laparoscopic environment, particularly right hemicolectomy procedures, such as those described above with reference to FIG. 1. The simulated organ is typically made of silicone or a thermoplastic elastomer (TPE) and is placed in a tray 28. The tray 28 is configured to accommodate a model organ contained within the tray 28. The tray 28 has a base and at least one side wall that is typically formed around the periphery of the base. Additional side walls are formed inside the periphery to define locations specific to anatomical structures, and are configured to accommodate simulated structures and tissues. These additional side walls provide lateral support in response to forces applied by the physician while the model 26 is contained within the cavity 18 and the physician manipulates the simulated organ with instruments inserted through the top cover 12 of the training device 10. FIG. 2 shows a simulated omentum layer 32 overlying a model liver 30 and other organs made of silicone disposed along the top of a tray 28, including their respective vasculature 34.

[0015] Referring to FIG. 3, the omentum layer 32 is shown pulled back to expose the underlying simulated organs, including at least a portion of the large intestine 36 (shown alone in FIG. 4) that can be attached to the appendix 42 and sigmoid colon, at least a portion of the small intestine 38, the liver 30 including the gallbladder assembly, the stomach, duodenum, kidneys, ureters, the aorta 40 (shown alone in FIG. 5), blood vessels 44 representing arteries and veins, and connective tissue layers including the peritoneum, Gerota's fascia, and mesenteric layer 46 (shown alone in FIG. 6). The organs are assembled to represent the correct anatomical positioning and location present in the human body for surgical training with various laparoscopic instruments. The right colon model 26, sometimes referred to as the right intestine model 26, is assembled using silicone simulated organs with modifications to highlight important landmarks and features for surgical training of right hemicolectomy.

[0016] A base tray 28 is provided. The base tray 28 is made of yellow or red foam and is sized and shaped so that it can be inserted into the cavity 18 of the trainer 10. Alternatively, the base tray 28 may have a liner made of yellow or red foam that fits directly into the base tray 28 and the base tray 28 can be inserted into the laparoscopic trainer 10 with the liner. An additional foam section may be added to the left side of the foam base to simulate a right side wall. Another model base is provided to allow for the simulation of various body positions during the simulated surgical procedure. For example, the right colon model base 28 or liner may be made of vacuum formed plastic with an inclined angle at one end of the model 26. This angle may simulate reverse Trendelenburg positioning of the patient during the surgical procedure. Additionally, the model 26 may be constructed on a vacuum-formed plastic base with a curved shape molded to mimic the shape of the pelvis, which extends proximally to form the curved shape of the abdominal sidewall.

[0017] A sheet made of silicone is attached to the top of the model's base 28 to aid in the mounting and assembly of the simulated organs. A list of silicone organ simulants and their colors can be seen in Table 1 below. The colon 36, aorta 40 and mesentery 46 may remain substantially the size shown in Figures 2 and 3, or they may be shortened or shortened to better fit the base of the laparoscopic training device 10. These anatomical structures are attached to the top of the foam base tray 28 in a manner that closely represents their exact relative anatomical positioning.

[0018] Table 1: Organs and their colors TIFF2025028868000002.tif98143

[0019] The mesenteric layer 46 encapsulates the artery and vein 44 and is adapted to be grasped and dissected using a laparoscopic dissector. Dissection between tissue layers has characteristics that cannot be simulated with silicone alone. Therefore, to solve this problem, several variations of dissectable simulated tissue suitable for simulating real anatomical structures, such as the mesentery 46, have been developed. The dissectable simulated tissue suitable for simulating the mesentery 46 is composed of three layers stacked on top of each other. The three layers include a top layer 48, a bottom layer 50, and a middle layer 54. The top layer 48 and the bottom layer 50 may represent the peritoneum layer, and the middle layer 54, which is made of gel, may represent the connective tissue surrounding the blood vessels 44, which is made of dissectable silicone.

[0020] 7A-7E, the construction of the dissectable simulated tissue of the present invention that can be used as an example mesenteric layer 46 will now be described. As noted, the dissectable simulated tissue 47 of the present invention is not limited to use as a mesenteric layer 46, and such dissectable simulated tissue can form at least a portion of any simulated tissue structure. The construction of the dissectable simulated tissue 47 includes the initial step of making two separate thin silicone sheets, one sheet for the top layer 48 and one sheet for the bottom layer 50, which are fully cured as shown in FIG. 7A. Once the sheets are fully cured, thin silicone gel layers 58a, 58b are spread using a spatula or similar tool onto the unpatterned sides of the silicone sheets 48, 50, respectively, as shown in FIG. 7B. The simulated vasculature 44, including silicone blood vessels, is placed onto one of the uncured gel layers 58a, 58b. FIG. 7C shows the simulated vasculature 44 placed on the uncured gel layer 58a on the sheet of top layer 48. The silicone sheets 48, 50, along with the gel layers 58a, 58b, are then fully cured to attach the simulated vasculature 44 to the top layer 48. Once the gel lining layers 48, 50 are cured, a third or middle layer 54 of new silicone gel is prepared and poured onto one of the layers 48, 50. In one variation, new silicone gel is poured onto the silicone sheet 48 where the silicone vessels 44 are placed. The gel is spread to completely cover the simulated vessels of the vasculature 44. The second layer 50 is then placed on top of the first layer 48 over the middle layer 54 while the silicone is still an uncured gel and extrudes to the edges with air pockets creating a sandwich-like structure. As a result of this process, the three-layer dissectable simulated tissue 47 can be used to simulate a mesentery assembly 46, for example, as shown in FIG. 6, that is particularly suited and compatible for laparoscopic dissection and skeletonization of the encapsulated vasculature 44 located between the layers. The multiple layers provide an accurate and lifelike feel and function to the dissectable simulated tissue structure. Additionally, the dissectable simulated tissue 47 advantageously creates a variety of tissue planes through which a physician can hone their dissection skills.Not only does the model 26 provide the ability to dissect layers, but it also allows the physician to properly identify tissue planes or layers 44, 48, 50, 54, 58a, 58b, which is an important skill to learn for each individual procedure. In one variation, a dissectable simulated tissue 47 is constructed without the vasculature layer 44, and such a dissectable simulated tissue can also be used to perform dissections.

[0021] During the process of making the dissectable simulated tissue 47, several additives are introduced that result in various desired properties and iterations of the dissectable simulated tissue 47. A list of various ingredients for the outer first and second layers 48, 50 and the inner or middle layer 54 of the dissectable mesenteric layer 46 is shown in Table 2, which is summarized in the flow chart of Figures 8A and 8B. A flow chart for determining the optimal dissectable sheet based on the desired properties of Figures 8A and 8B is shown in Figures 9A and 9B. In Figures 9A and 9B, the mesenteric layer is used as an example application of the dissectable simulated tissue of the present invention, and the flow chart of Figures 9A and 9B is not limited to the application for making only a simulated mesenteric layer, but includes use in any simulated tissue structure. Additionally, the vessels shown in Figures 9A and 9B are not limited to simulated vessels, but may include any simulated anatomical structure or tissue in the implanted state, including, but not limited to, tumors, pathological lesions, organs, ducts, cartilage, etc. The silicone outer layers 48, 50 are made of a conventional two part room temperature vulcanizing (RTV) silicone in a 1:1 ratio, or a 1:1 ratio of RTV silicone and deadener additive, or a 2:1 ratio of RTV silicone and deadener additive. RTV includes, but is not limited to, platinum cure room temperature vulcanizing silicone (PCRTVS). Silicone deadeners belong to a family of silicone fluid chemistries including, but not limited to, silicone oils, which are platinum cure silicone additives. One example of a deadener is called SLACKER, manufactured by Smooth-On, Inc. of Macungie, Pennsylvania. Deadening agents as additives soften silicone to resemble the feel of skin or human tissue, yet make it realistic. Silicone deadeners are silicone additives that can soften and modify the resulting "feel" and rebound properties of the cured silicone. This additive is in the chemical family of silicone fluids, which includes silicone oils. Silicone fluids and silicone oils have a range of uses that depend on the viscosity and chemical structure of the fluid.Silicone deadeners are a type of silicone oil that are miscible with platinum cure room temperature vulcanizing silicones.

[0022] The durometer of conventional silicones used to mold organs ranges from 00-10 Shore to 10A Shore. Thus, the addition of deadening agents results in different properties when added to silicones of different durometers. The addition of deadening agents to silicones that are soft in terms of durometer results in a gel-like composition upon full cure. However, the addition of deadening agents to high durometer silicones results in the desired characteristics of a soft-feeling silicone, which easily reaches its deformation break point upon full cure. Thus, the combination of silicone and deadening agent can provide the tactile characteristics of the outer layers 48, 50 that make up the mesentery 46, e.g., the peritoneal layer.

[0023] Variations of the intermediate layer include: (1) a gel containing a deadener or deadening agent; (2) a gel containing alcohol; (3) a gel containing alcohol and heat applied; or (4) a gel containing a deadener or deadening agent and alcohol and heat applied. Isopropyl alcohol is used. The addition of additives to the encapsulating gel layer 54 reduces the amount of pressure and force used to cut the layer and facilitates cutting the layer. The gel is a platinum cure silicone rubber gel that can be used as the intermediate layer 54 in the mesentery assembly 46. Another variation to facilitate cutting the intermediate layer 54 is to add alcohol to thin the gel, thus making it easier to penetrate the gel. Further degradation of the gel layer 54 can further increase the ease with which the intermediate layer 54 can be cut. The alcohol and gel mixture is heated to about 70° C. to speed up the setting time and create a porous intermediate layer 54 that occurs as a result of the evaporation of the alcohol. The porous intermediate layer 54, comprised of gel, alcohol and heat, reduces the inherent tackiness of the gel, making it easier to penetrate and dissect the mesenteric layer 48, 50, 54. In another variation, deadener is added to the silicone gel, resulting in a formulation that has low elastic properties but is more tacky when fully cured. To alleviate issues with the stickiness of the cured gel mixture, alcohol is added to the silicone gel and deadener mixture in the same ratio. The resulting properties, when fully cured, are less tacky compared to the gel mixture itself and the gel and deadener, but also provide the desired dissection feedback when using laparoscopic dissectors. Again, the addition of heat to the mixture creates a porous intermediate layer 54 with the characteristics listed above for the other dissection layer variations. The intermediate dissection layer 54 variation, comprised of gel and various additives, advantageously provides feedback to move through tissue and dissect free blood vessels contained within the mesenteric layer 46 between the two outer layers 48, 50. Additionally, the formulated gel variations provided herein impart a realistic, wet appearance to layer 54 that provides a sheen or luster that is particularly advantageous in laparoscopic procedures where the cavity is enclosed and illuminated by a laparoscope.

[0024] Table 2: Layers and materials TIFF2025028868000003.tif62157

[0025] The vasculature 44 present in the right colon model 26 is made from silicone or KRATON polymer tubing manufactured by Kraton Polymers of Houston, Texas. The blood vessels are contained within the simulated mesenteric layer 46 described above. The vasculature 44 is anatomically positioned and attached to the peritoneal layers 48, 50 by a gel intermediate layer 54. Additionally, although the dissectable tissue containing the vasculature 44 has been described with respect to a right hemicolectomy model, this method of manufacture can be utilized for any tissue simulated model by similar means or as a stand-alone model for a simulated tissue platform.

[0026] Another component of the right colon tray is the omentum 32. The omentum 32 is attached over the large intestine 36, which is hung on top of the model 26. Several variations of the omentum 32 have been developed. The first variation is a textured silicone cast omentum 32 that can be easily hung on top of the model 26. However, to simulate the weight and feel of the omentum 32, the omentum may also be cast using soft silicone foam. The foam omentum 32 is colored yellow, which appears to take up a large amount of space in the abdominal cavity, but can be hung on top of the model 26. Vasculature 34 is present on both variations of the omentum 32 to simulate the appearance of the omentum 32 as it would appear in the body.

[0027] Referring back to FIG. 3, the presence of attachments 64 on the model connecting the ascending colon 60 to the abdominal wall 62 is an important feature for training the right hemicolectomy procedure. To address the abdominal wall 62, several identical models are made. The first model of the abdominal wall 62 is made by attaching a long thin piece of foam approximately 2 inches (5.08 cm) in height to the side of the base 28, which may also be made of foam. The abdominal side walls 62 may also be built into the base 28 through the curvature of the molded base and side walls described above. Finally, the abdominal sides 62 may be made of a curved, rigid, hard cast material that extends the length of the foam base 28 and is attached to the foam base 28. An outer attachment 64 may be attached to any of the abdominal walls 62 described above. The outer attachment 64 is made by using two textured silicone sheets that are attached to the top of any of the later abdominal walls 62 described above. Between the two sheets that are attached to the abdominal wall 62 is the linea alba of Tolt. There are several models for the linea alba of Tolt. The first phantom simulates the linea alba of Tolt with rope fiber. Strands of white cotton rope are used in the model 26 to mimic the appearance of the vasculature plane of the linea alba of Tolt. The linea alba of Tolt can also be simulated by creating white stripes or fringes in silicone to represent anatomical landmarks. The linea alba of Tolt is attached between two layers of silicone sheeting, which are then attached to each other along the edges and then to the ascending colon 60. The resulting structure is an outer attachment that connects to the side wall 62 containing the intestine 36.

[0028] In another aspect of the present invention, the dissectable simulated tissue 47 is made of at least two distinct layers. The first layer is made of a silicone layer and the second layer is made of a silicone gel. The dissectable simulated tissue 47 can be used to create synthetic tissue and organ models with anatomical similarity and can be used as a simulated training model for training in dissection and other surgical procedures. The dissectable simulated tissue 47 of the present invention is an assembly made of at least one outer silicone layer and a gel layer encapsulated by one or more outer silicone layers, resulting in a structure that closely resembles an incision observed by a surgeon. The one or more silicone layers of the dissectable simulated tissue are made of two-part RTV10A durometer silicone mixed with a silicone deadener that accounts for 33% of the total weight, resulting in a 2:1 ratio of total silicone to deadener used. Deadener is a silicone oil that softens the properties of the cured silicone to which it is added. As a result, a 10A durometer silicone to which deadener is added will cure to a durometer silicone less than 10A. The amount of deadener added is proportional to the change in durometer properties to which it is added. A silicone pigment is added to the silicone and deadener mixture, which causes the silicone to be cast to create a viscous mixture with the pigment corresponding to the anatomical structure it represents. The silicone mixture is cast onto a sheet of foam, optionally with texture, or onto a textured sheet made of a gypsum material. The cast silicone mixture is cured at room temperature for about 45 minutes if foam is used, or in an oven at a temperature of about 70°C for about 25 minutes if foam is not used. The sheet size may have a length and width that varies depending on the size of the plane or surface being incised.

[0029] Once the silicone sheet has cured, it is placed on a mold with a rectangular cavity, the cavity being smaller than the silicone size. The silicone sheet is placed on the mold such that the central region of the sheet is placed in the cavity and the outer periphery of the sheet is laid flat on the surface of the mold. Providing this set-up configuration facilitates the gel encapsulation process with minimal gel leakage. Within the central cavity, the silicone vasculature and pathological lesion, e.g., tumor, are attached using a silicone adhesive onto the portion of the sheet located within the cavity. The placement of the vasculature and pathological lesion resembles the anatomical tissue where incisions are typically performed. When the silicone adhesive cures and the vasculature and pathological lesion are intact, an intermediate gel layer is created. The present invention is not limited to the implantation of vasculature, but also includes other anatomical landmarks and structures, including but not limited to vasculature, tumors, pathological lesions, organs and tissue structures, and their construction materials, including but not limited to any polymeric material, silicone, KRATON, etc.

[0030] In one variation, the encapsulating gel present in the dissectable simulated tissue is composed of silicone gel, deadener, and isopropyl alcohol. To make the gel, the two-part silicone gel is placed in a mixing cup in equal parts by weight and volume. Deadener is added in an amount equal to the total silicone addition volume. Isopropyl alcohol is added in an amount equal to the volume of deadener. The mixture is mixed until a homogenous solution is obtained. Silicone pigments can be added as needed to create a pigment that closely resembles the human tissue to be dissected. Once the solution is thoroughly mixed, it is cast on top of the outer silicone sheet that is placed in the cavity of the mold to create a gel layer. The gel is encapsulated and does not pass over the top of the cavity, as this would cause gel leakage, which would be detrimental to the overall tissue model. The silicone gel is a silicone elastomer. However, it is platinum-cured silicone rubber that is extremely soft. The durometer of silicone gels is below the Shore 00 hardness scale, which makes the gel soft, sticky, and has low tear resistance. One example of a gel used for dissectable tissue is ECOFLEX gel, manufactured by Smooth-On, Inc., which has a hardness of 000-35.

[0031] At this point of manufacture, there are two separate ways to complete the dissectable simulated tissue model. For example, the dissectable simulated tissue can be consumed as a component in an organ tray targeted to training surgical procedures as described with reference to Figures 1-6. In such a case, if the dissectable simulated tissue is consumed as a component in a tray, a second silicone sheet having the same size and silicone, deadener, and pigment reanimation as the first silicone sheet is used to encapsulate the gel layer. The second silicone sheet is placed on the first sheet containing the gel. The layer is pressed so that air pockets are pushed to the side of the sheet and released into the atmosphere. A silicone adhesive is used to line the perimeter of the cavity between the two silicone sheets, thereby creating a seal between the two silicone layers to prevent leakage of the gel. The gel is allowed to cure at room temperature between the two silicone sheets. Once cured, the dissectable simulated tissue can be removed from the casting mold. The perimeter of the silicone sheet can be used to attach the dissectable simulated tissue to various silicone organs in the organ tray. The dissectable simulated tissue 47 may be specifically constructed for a simulated organ training tray for training in a right hemicolectomy procedure as shown in FIGS.

[0032] In another example, the dissectable simulated tissue 46 can be utilized on a small platform to train only on dissection skills. In this case, once the gel layer is poured into the cavity, it is cured in an oven at about 60° C. for about 35 minutes. Once the gel is cured, a 10A durometer silicone mixture is prepared with the same pigment as the outer silicone sheet of the dissectable simulated tissue. To form a second silicone sheet layer, a silicone mixture is cast onto the gel and the outer silicone sheet layer, and then cured in an oven at about 60° C. for about 30 minutes. The resulting dissectable simulated tissue model is a stand-alone model that can be used to practice dissection skills. This model of the dissectable simulated tissue is a one-sided model, in this case only one of the outer layers is soft silicone with similar properties to human tissue. The outer layer, constructed of 10A durometer silicone, serves as a taut support for the model when placed within a suturing platform of the type described, for example, in U.S. patent application Ser. No. 14 / 037,005, filed Sep. 25, 2012, entitled "Surgical training model for laparoscopic procedures," which is incorporated by reference in its entirety.

[0033] The deadening agent as an additive added during the preparation of the outer silicone layer makes the silicone soft and realistic to the touch of skin or human tissue after curing. The addition of deadening agents results in different properties when added to silicones with different durometers. The addition of deadening agents to durometer-soft silicones results in a gel-like composition upon full curing. However, the addition of deadening agents to durometer-high silicones results in the desired characteristics of soft-feeling silicones, which easily reach their deformation breaking point upon full curing. Thus, the combination of silicone and deadening agent can provide the tactile characteristics of human tissues that make up the mesentery, such as the peritoneum layer.

[0034] The intermediate gel layer comprises a gel containing deadener, with alcohol added and heat applied. The addition of each additive to the encapsulating gel layer reduces the amount of pressure and force used to make the incision, thereby facilitating the incision. The gel is a platinum cured silicone rubber gel that can be used as an intermediate dissectable layer in a dissectable simulated tissue. Alcohol is added to thin the gel, thereby making the intermediate layer easier to incise and penetrate. Additionally, degradation of the gel layer can further enhance the dissectable properties of the intermediate layer. The alcohol and gel mixture is heated to speed up the curing time and create a porous intermediate layer due to evaporation of the alcohol. The porous intermediate layer composed of gel and alcohol reduces the inherent tackiness of the gel and makes it easier to penetrate and incise the encapsulating gel layer. In another variation, deadener is added to the silicone gel, resulting in a formulation with reduced elastic properties but increased tackiness when fully cured. To alleviate issues with tackiness of the cured gel mixture, alcohol is added to the silicone gel and deadener mixture in the same ratio. The resulting properties, when fully cured, are less tacky compared to the gel mixture itself and the gel plus deadner, but also provide the desired dissectable feel when used with laparoscopic dissectors. Again, application of heat to the mixture creates a porous intermediate layer having the characteristics listed above for the other variations of the dissectable layer. The construction of the intermediate dissectable layer, comprised of gel and various additives, provides the feel of moving through the tissue to dissect free blood vessels within the mesenteric layer or other tissue structure or organ. Additionally, the use of a gel sheen or glaze provides a realistic wet appearance similar to that of real tissue, which is particularly useful when viewed on a video monitor during training of laparoscopic skills.

[0035] Variations in making the outer silicone layer include changing the durometer of the silicone. RTV platinum cured silicones, which are useful for making simulated organ models, have a 00-10 durometer and a 10A durometer, and the silicone outer layer can be made with either silicone. Additionally, deadeners can be added to the silicone to soften the cured form of the silicone. The change in softness and elasticity of the silicone is directly proportional to the amount of deadener added. Figure 8A shows a flow diagram of the outer silicone layer forming the dissectable simulated tissue.

[0036] The middle gel layer is made of a base silicone gel to which additives including deadener and alcohol are applied and heat is applied to cure. Each additive is eliminated separately to provide variations at each step and result in properties for each configuration. FIG. 8B shows variations of each gel layer composition with additives in specific ratios and properties exhibited by those additives. Throughout this specification for all embodiments, ratios for the outer layers can be either by volume or by weight since the densities of the silicone and deadener are approximately equal. The ratios of the gel layer, deadener, and alcohol are by volume.

[0037] A variation in the assembly of the dissectable simulated mesenteric layer may include the use of silicone gel to hold the vasculature together. The construction of this assembly involves the initial step of making two separate sheets of silicone with deadeners and allowing them to fully cure as shown in FIG. 7A. Once the sheets are fully cured, a spatula or similar tool is used to spread a thin layer of silicone gel 58a, 58b onto the plain side of each of the silicone sheets 48, 50 as shown in FIG. 7B. The vasculature 44 made of silicone vessels is placed onto the uncured gel layer 58a on one of the sheets as shown in FIG. 7C. The silicone sheets 48, 50 including the gel layers 58a, 58b are allowed to fully cure. Once the gel liner layer is cured, new silicone gel 54 is prepared and cast onto the silicone sheet 48 with the silicone vessels 44 in place. The gel 54 is spread so that it completely covers the vessels 44 as shown in FIG. 7D. A second silicone sheet 50 is then placed onto the uncured gel and any air pockets are pushed out to the edges. As a result of this process, the multi-layered mesentery may be compatible with laparoscopic dissection as shown in FIG. 7E.

[0038] The dissectable simulated tissue of the present invention has the mechanical properties of low tear resistance, elasticity, toughness, color, and texture of the representative tissue to be dissected. A laparoscopic tool, such as a Maryland dissecting container or laparoscopic scissors, can be used in the tissue to dissect or cut the tissue, respectively. The use of gel in the dissectable tissue imparts a unique sheen to the material, which allows the material to have a realistic wet appearance. The gel used to construct the dissectable tissue is silicone-based, so that the gel can be bonded to various other silicone models or other organs already manufactured, such as silicone blood vessels. Furthermore, the viscosity of the gel allows blood vessels made of other thermoplastic elastomers, such as KRATON polymer, to be attached to the outer silicone layer with silicone gel.

[0039] The dissectable simulated tissue of the present invention is dissectable and has several advantageous properties that closely resemble human tissue. The simulated tissue mimics the mechanical properties of human tissue, such as elasticity, toughness, color, and texture. The simulated tissue also has low tear resistance or tear strength, which advantageously allows for the propagation of tissue separation. The low tear resistance of the simulated tissue facilitates blunt dissection using laparoscopic Maryland dissectors or laparoscopic scissors with minimal force. The simulated tissue may also include anatomical landmarks or structures of representative anatomical structures that require dissection. These anatomical landmarks or structures include, but are not limited to, organs, vasculature embedded between mesenteric layers, or peritoneal sheets surrounding pathological lesions that need to be excised, such as tumors. The anatomical landmarks or structures can be grasped using atraumatic laparoscopic graspers or Maryland dissectors or cut using laparoscopic scissors. In addition, the dissectable simulated tissue of the present invention allows for manipulation and manipulation of anatomical structures upon completion of the dissection. The movement of these structures closely resembles the movement of the anatomical structures of human tissue upon completion of the dissection. In addition, the dissectable simulated tissue can be consistently manufactured. The simulated tissue can be molded to assume the shape of a human organ or membrane. The dissectable simulated tissue can also be bonded with a variety of silicone and thermoplastic resins. In the present invention, any and all of the silicone layers can be translucent or transparent to allow for a slight view of the underlying implanted pathological lesion, tumor, vasculature, etc. through one or more of the layers.

[0040] Working Example

[0041] With reference to Figures 9A-9H, an embodiment of manufacturing a simulated tissue model having a bias with a dissectable simulated tissue composition will now be described. A 10A durometer silicone is prepared that includes two parts, part A and part B. Approximately 5 grams of part A of the 10A durometer silicone is mixed with approximately 5 grams of part B of the 10A durometer silicone. Approximately 5 grams of silicone deadener is added. Yellow silicone pigment is added. The silicone, deadener and pigment are thoroughly mixed. The mixture is cast onto a textured mold and allowed to cure to form a first layer sheet 66 as shown in Figure 9A. A rectangular mold 68 is prepared with a central cavity 70 approximately 0.125 inches (3.175 mm) deep as shown in Figure 9B. The depth of the central cavity 70 can be varied depending on the desired dissectable thickness. A vasculature template 72 is placed within the central cavity of the rectangular mold as shown in Figure 9B. The template 72 shows lines 74 where silicone vessels should be placed for the correct anatomy. The template 72 further includes an indication of anatomic location 76 where a particular pathological lesion should be placed. Although a vasculature template 72 is disclosed, the invention is not limited thereto and any anatomical feature template 72 can be used with the template 72 oriented to where a particular structure, pathological lesion, organ, tumor and other tissue and anatomical landmark should be placed. The first layer sheet 66 is then placed on the mold 68 so that it aligns with the outer edge of the mold 68 as shown in FIG. 9C. The first layer sheet 66 is transparent so that the template 72 can be viewed through the first layer sheet 66. The simulated vasculature 78 and simulated tumor 80 are then attached to the first silicone sheet layer 66 using silicone adhesive and placed in the location shown on the underlying template 72 as shown in FIG. 9D. The simulated vasculature 78 is placed on the lines 74 of the template 72. Lines 74 or other shapes on template 72 may be further colored to place correspondingly colored vessels and / or organs in their correct anatomical locations. Mix approximately 3.3 grams of Part A Silicone Gel with approximately 3.3 grams of Part B Silicone Gel.Approximately 6.67 millimeters of silicone deadener and 5.27 grams of isopropyl alcohol are added to the silicone gel and mixed together. By volume or volume measurement, these will be approximately 3.3 milliliters of Part A silicone gel, approximately 3.3 milliliters of Part B silicone gel, 6.67 milliliters of silicone deadener, and 6.67 milliliters of isopropyl alcohol mixed together. The yellow and white silicone contents are added and mixed. The mixture is poured into the center cavity to surround the simulated vasculature 78 but not to leak beyond the cavity, thereby forming the middle gel layer 82 as shown in FIG. 9E. All of the components are cured in an oven at approximately 60° C. for approximately 35 minutes. The middle gel layer 82 is also clear when cured, thus allowing the simulated blood vessels 78 and the simulated tumor 80 to be visible through the middle gel layer 82. Approximately 35 grams of Part A and 35 grams of Part B of 10A durometer silicone are mixed together. Silicone is cast onto the cured gel and sides of the model to form a second outer layer 84. The model is then cured in an oven at about 60° C. for about 25 minutes. The second outer layer 84 is also clear, allowing the embedded landmarks in the gel layer 82 and outer layer 84 combination, such as the simulated tumor 80 and the simulated blood vessels 78, to be visible through the layers 66, 82, 84. The excess perimeter of the silicone sheet sandwich is trimmed off so that the model measures approximately 4 inches by 5 inches (10.16 cm by 12.7 cm) and the middle gel layer 82 is encapsulated by the two surrounding outer layers 66, 84. The perimeter of the model is made of the two outer layers 66, 84 attached together with no middle gel layer 82 between them to prevent leakage of the gel layer 82 from the model. The outer layers 66, 84 serve to seal and encapsulate the gel middle layer 82. 9G and 9H, four holes 86 are drilled into the corners of the rectangular model and the model is placed on upright pegs 88 of a simulated tissue platform 90 so that it can float like a trampoline and allow for cutting practice.The simulated tissue model of Figures 9A-9H is a model of the vasculature in the vicinity of the gallbladder and may be considered a partial gallbladder model, which may or may not include a simulated gallbladder. In use, the model is suspended on a platform 90 or forms part of a larger organ model or organ tray and placed in a surgical simulation and / or training device for a physician to train a surgical procedure on the model. The model may also be used outside of the simulation and / or training device. Still referring to Figure 11, the physician cuts into the second outer layer 84 to enter the middle gel layer 82. The physician spreads the second outer layer 84 away from the first outer layer 66, thereby accessing the implanted structures, the simulated blood vessel 78 and the simulated tumor 80. In doing so, the physician may need to separate or cut open the middle gel layer 82. The middle gel layer 82 is soft, shiny, and elastic. Upon lifting the second outer layer 84, the soft elastic gel of the intermediate layer 82 advantageously resembles a fibrous membrane as it stretches when the second outer layer 84 is moved away from the first outer layer 66. As the intermediate gel layer 82 stretches, it advantageously opens into a deep pocket with the strands of gel 92 remaining interconnected between the two layers where the surgeon practices cutting through the strands of gel. Blunt or sharp dissection of the soft silicone gel follows to open a space, thereby creating a dissection plane through the intermediate gel layer 82 and between the first outer layer 66 and the second outer layer 84. The anterior layers may also be cut and divided to provide further visibility of structures such as the simulated vasculature 78 embedded within the intermediate gel layer 82, thereby simulating skeletonization.

[0042] It will be appreciated that various modifications can be made to the embodiments of the dissectable simulated tissue disclosed herein. Thus, the above description should not be construed as limiting the invention, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications that are within the scope and spirit of the invention.

Claims

1. 1. A dissectable simulated tissue for surgical training, comprising: a first layer having an inner surface and an outer surface, the first layer being made of silicone, the first layer defining a thickness between the inner surface and the outer surface; a second layer having an inner surface and an outer surface, the second layer being made of silicone, the second layer defining a thickness between the inner surface and the outer surface; A dissectable simulated tissue having a third layer of silicone gel disposed between the first and second layers of silicone gel.

2. The dissectable simulated tissue of claim 1 , further comprising one or more simulated anatomical structures disposed between the first layer and the second layer.

3. The dissectable simulated tissue of claim 2 , wherein the one or more simulated anatomical structures are attached to one of the first layer and the second layer.

4. The dissectable simulated tissue of claim 2 , wherein the one or more simulated anatomical structures are embedded within the third layer between the first layer and the second layer.

5. 3. The dissectable simulated tissue of claim 2, wherein the simulated anatomical structure is selected from the group consisting of vessels, vasculature, pathological lesions, tumors, organs, organ subsections, and ducts.

6. The dissectable simulated tissue of claim 2 , wherein the simulated anatomical structure is made of silicone or KRATON.

7. The dissectable simulated tissue of claim 1 , wherein the first layer and the second layer form a single layer configured to surround the third layer.

8. The dissectable simulated tissue of claim 1 , wherein the third layer is surrounded by the first layer and the second layer.

9. The dissectable simulated tissue of claim 1 , wherein the first layer and the second layer form a sealed pocket to receive the third layer.

10. The dissectable simulated tissue of claim 1 , wherein the first layer has a first perimeter, the second layer has a second perimeter, and the first perimeter and the second perimeter are joined to form at least one cavity within the first and second perimeters to accommodate the third layer.

11. The dissectable simulated tissue of claim 1 , wherein the durometer of the silicone of one or more of the first and second layers is about 00-10 Shore or 10A Shore.

12. The dissectable simulated tissue of claim 1 , wherein one or more of the first layer and the second layer comprises a mixture of silicone and deadener.

13. 13. The dissectable simulated tissue of claim 12, wherein the ratio of silicone to deadener is about 1:1 or 2:1 parts by weight or volume.

14. The dissectable simulated tissue of claim 1 , wherein the third layer further comprises alcohol.

15. 15. The dissectable simulated tissue of claim 14, wherein the third layer has a ratio of about 1 part silicone gel by volume to about 1 part alcohol by volume.

16. The dissectable simulated tissue of claim 14 , wherein the third layer is formed by heating the mixture of silicone gel and alcohol.

17. The dissectable simulated tissue of claim 14 , wherein the third layer further comprises a deadener.

18. 20. The dissectable simulated tissue of claim 17, wherein the third layer has a ratio of about 1 part silicone gel, 1 part alcohol, and 1 part deadener by volume.

19. The dissectable simulated tissue of claim 17, wherein the third layer is formed by heating the mixture of silicone gel, alcohol and deadener by placing the mixture in an oven at a temperature of at least 60°C for approximately 25 minutes.

20. The dissectable simulated tissue of claim 1 , wherein the third layer includes a deadener.

21. 21. The dissectable simulated tissue of claim 20, wherein the third layer has a ratio of about 1 part silicone gel by volume to 1 part deadener by volume.

22. 1. A dissectable simulated tissue for surgical training, comprising: an outer shell configured to define an interior cavity, the outer shell being made of silicone; a filler disposed within and sealed within the internal cavity, the filler including a silicone gel; A dissectable simulated tissue, wherein the outer shell is detachable at the location of the filler.

23. 23. The dissectable simulated tissue of claim 22, wherein the outer shell comprises a mixture of silicone and deadener, and the filler comprises a mixture of silicone gel and deadener.

24. 24. The dissectable simulated tissue of claim 23, wherein the ratio of silicone gel to deadener is about 1:1 by volume for the filler.

25. 25. The dissectable simulated tissue of claim 24, wherein the ratio of silicone to deadener is about 1:1 or about 1:2 by weight for the outer shell.

26. 23. The dissectable simulated tissue of claim 22, wherein the outer shell comprises a mixture of silicone and deadener, and the filler comprises a mixture of silicone gel, deadener and alcohol.

27. 27. The dissectable simulated tissue of claim 26, wherein the filler comprises silicone gel, deadener, and alcohol in a ratio of about 1 part silicone gel, 1 part deadener, and 1 part alcohol by volume.

28. 27. The dissectable simulated tissue of claim 26, wherein the filler is heated by placing it in an oven at a temperature of at least 60°C for about 25 minutes.

29. 23. The dissectable simulated tissue of claim 22, wherein the outer shell comprises a mixture of silicone and deadener, and the filler comprises a mixture of silicone gel and alcohol.

30. 30. The dissectable simulated tissue of claim 29, wherein the ratio of silicone to deadener is about 1:1 or 1:2 by weight for the outer shell.

31. 30. The dissectable simulated tissue of claim 29, wherein the filler comprises a mixture of silicone gel and alcohol in a ratio of about 1 part silicone gel to 1 part alcohol by volume.

32. 30. The dissectable simulated tissue of claim 29, wherein the filler is heated by placing it in an oven at a temperature of at least 60°C for about 25 minutes.

33. 23. The dissectable simulated tissue of claim 22, further comprising one or more simulated anatomical structures embedded within said filler.

34. 34. The dissectable simulated tissue of claim 33, wherein the simulated anatomical structure is selected from the group consisting of a vessel, a vasculature, a pathological lesion, a tumor, an organ, a partial organ, and a duct.

35. 1. A method for producing dissectable simulated tissue for surgical training, comprising: Providing a first layer of silicone; curing the first layer; Providing a mold with a central cavity; placing the first silicone layer onto the mold such that the first layer covers the central cavity; Preparing a silicone gel; applying an uncured silicone gel onto the first layer; Providing a second layer of silicone; disposing the second layer over the silicone gel and the first layer; curing the silicone gel; and curing the second layer.

36. Providing at least one simulated anatomical structure; placing the simulated anatomical structure on the first layer and then applying the uncured silicone gel; 36. The method of claim 35, wherein the step of applying the uncured silicone gel onto the first layer comprises applying the uncured silicone gel onto the simulated anatomical structure.

37. 37. The method of claim 36, wherein the step of providing at least one simulated anatomical structure comprises providing at least one simulated anatomical structure made of silicone.

38. 36. The method of claim 35, wherein the step of curing the silicone gel occurs before the step of curing the second layer.

39. 36. The method of claim 35, wherein the step of preparing a silicone gel comprises mixing silicone gel and alcohol in about a 1:1 ratio by volume.

40. 36. The method of claim 35, wherein preparing a silicone gel comprises mixing a silicone gel and a deadener in about a 1:1 ratio by volume.

41. 36. The method of claim 35, wherein the step of preparing a silicone gel comprises mixing silicone gel, deadener, and alcohol in a ratio of about 1:1:1 by volume.

42. 42. The method of claim 39 or 41, wherein the step of curing the silicone gel comprises heating the silicone gel by placing the silicone gel in an oven at a temperature of at least 60° C. for about 20 to 40 minutes.

43. 36. The method of claim 35, further comprising placing the first layer, the second layer and the silicone gel in an oven at a temperature of about 60 degrees Celsius for about 25 minutes.

44. 36. The method of claim 35, further comprising sealing the silicone gel between the first layer and the second layer.

45. 36. The method of claim 35, further comprising attaching at least one simulated anatomical structure to the first layer or the second layer, and wherein the step of applying the uncured silicone gel onto the first layer comprises applying the uncured silicone gel onto the simulated anatomical structure.

46. providing a template for the simulated anatomical structure; and placing the template within the central cavity of the mold; 37. The method of claim 36, wherein the step of disposing the first silicone layer on the mold comprises disposing the first silicone layer on the template.

47. 36. The method of claim 35, further comprising adhering the first layer and the second layer to one another to enclose and seal the silicone gel.

48. 1. A method for producing a dissectable simulated tissue having one or more outer layers encapsulating an inner layer, comprising: selecting a material for the outer layer, the step of selecting a material for the outer layer comprising selecting one of a silicone and a mixture of silicone and a deadener; The method includes selecting a material for the inner layer, the step of selecting a material for the inner layer including selecting one of a silicone gel and a mixture of silicone gel and deadner.

49. 49. The method of claim 48, wherein the step of selecting a material for the inner layer includes the step of selecting a silicone gel and mixing the silicone gel with alcohol.

50. 49. The method of claim 48, wherein the step of selecting a material for the inner layer includes the step of selecting a silicone gel and mixing the silicone gel with alcohol in approximately a 1:1 ratio by volume.

51. 50. The method of claim 49, further comprising the step of heating the mixture of silicone gel and alcohol by placing the mixture in an oven at a temperature of at least 60 degrees Celsius for about 25 minutes.

52. Providing at least one simulated anatomical structure made of silicone or KRATON; 50. The method of claim 49, further comprising the step of encapsulating the simulated anatomical structure together with the inner layer.

53. 49. The method of claim 48, wherein the step of selecting a material for the inner layer includes selecting a mixture of silicone gel and deadener.

54. 49. The method of claim 48, wherein the step of selecting a material for the inner layer includes selecting a mixture of silicone gel and deadener in about a 1:1 ratio by volume.

55. 49. The method of claim 48, wherein the step of selecting a material for the inner layer includes the step of selecting a mixture of silicone gel and deadener and mixing the mixture with alcohol.

56. 49. The method of claim 48, wherein the step of selecting a material for the inner layer includes the step of selecting a mixture of silicone gel and deadener and mixing the mixture with alcohol in a ratio of approximately 1:1:1 by volume.

57. 56. The method of claim 55, further comprising the step of heating said mixture of silicone gel, deadener and alcohol by placing said mixture in an oven at a temperature of at least 60°C for about 25 minutes.

58. Providing at least one simulated anatomical structure made of silicone or KRATON; 54. The method of claim 53, further comprising the step of encapsulating the simulated anatomical structure together with the inner layer.

59. Providing at least one simulated anatomical structure made of silicone or KRATON; 56. The method of claim 55, further comprising encapsulating the simulated anatomical structure together with the inner layer.

60. 49. The method of claim 48, further comprising the step of encapsulating the inner layer with the outer layer.

61. The step of encapsulating the inner layer with the outer layer comprises: Providing a first outer layer; depositing the inner layer onto the first outer layer; Providing a second outer layer; applying the second outer layer over the inner layer; and adhering said first outer layer to said second outer layer at a location surrounding said inner layer.

62. 62. The method of claim 61, further comprising the step of applying pressure to substantially remove any air present between the first outer layer and the second outer layer.

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