DESC:TECHNICAL FIELD
The present disclosure in general relates to surgical simulators and methods of the preparation thereof. Particularly, the present invention relates to a high-fidelity surgical simulation device for simulating surgical operations on close to real-life tubular and other internal organs and a process of preparation of the surgical simulation device. More particularly, the present invention relates to a composition for forming model organs for a surgical simulation device and a process for preparation of model organs for a surgical simulation device. Further the present invention relates to a high-fidelity surgical simulation device for tracheoesophageal fistula.
BACKGROUND
Laparoscopic and Thoracoscopic surgeries are the recent advances in surgery that offer advantages of better visibility, less pain and early recovery to the patients.
These surgeries have also been adopted in children, however, the space available in the chest cavity in children is limited, especially in newborn children. The surgery is done by opening the chest and this causes lot of morbidity during the post operative period and even chest deformity in later life. To perform the surgery by thoracoscopic approach, a high degree of surgical expertise is required. Further, it is difficult to manoeuvre the delicate instruments in the little space available to perform the required operations of cutting and suturing.
One of such medical condition wherein these surgeries is performed is Oesophageal atresia with tracheoesophageal fistula, which is a congenital condition in which the food pipe is not formed completely, is rather blind ended and the lower part of the Oesophagus (food pipe) is connected to the trachea (windpipe). The condition is life threatening as the baby cannot take anything by mouth and if given by mistake the milk goes to the chest and causes pneumonia. The condition needs immediate repair once the chest condition of the baby is stable. Also, the operation involves dividing the fistula and perform the anastomosis (suture together) of the two ends of Oesophagus.
The acquisition of surgical techniques traditionally involves physical practice, such as making incisions and suturing on living creatures (e.g., animals), cadavers, or models (e.g., carpet remnants), however, each of these methods has drawbacks. Using living animals incurs high costs and faces societal opposition/ ethical dilemmas due to cruelty to animals. Cadavers lack realistic conditions, involve high expenses, and tend to decompose quickly giving out intense putrid smell. Practicing on carpet remnants is affordable but lacks correlation to the actual tissue, potentially leading to incorrect techniques.
Accordingly, a need arises for the simulated anatomical models addressing these challenges. Various medical models for surgery have been developed and the models fall into distinct categories, each serving specific functions in surgical practice. These categories include (i) models for anatomy which includes physical models made of materials like rubber for surgeons to practice procedures and plan surgeries and computer-generated 3D models offering virtual representations of patient anatomy for instructional purposes; (ii) models for surgical simulation which includes physical simulation models replicating the feel and reaction of human tissues to enhance surgeon proficiency. The physical models can be pathological models, disease-specific models, models for functional anatomy, physiological models, patient-dependent modelling and also 3D printing of anatomy tailored to the patient.
Various models are available, however there are limitations associated with the reported models. Particularly, depending on the research's objective, models are evaluated through parametric (objective) methods and those based on experience, and interviews (subjective). Parametric evaluation commonly involves measurements made using diagnostic equipment like medical imaging (MRI, CT, or ultrasonography) or medical tools such as an endoscope (1). Anatomical models find application in various medical areas, notably pre- and intraoperative support, allowing controlled conditions for simulated surgeries (2). Different materials are used in medical models for suturing practices, like collagen which has good biocompatibility, cell interaction, mechanical strength, moisture retention, low immunogenicity, and biodegradability (3), hyaluronic acid (HA) which has low immunogenicity and is approved for clinical use (4), silicones having non-toxicity, non-reactive, biocompatibility leading to extensive medical applications (5), expanded polytetrafluoroethylene (ePTFE), which acts as an inert polymer tissue filling material with good biological scaffolding properties, biocompatibility, and soft texture (6), polymethyl methacrylate (PMMA), which is usually injected for facial aesthetics, (7), Aqumid (polyacrylamide gel), which is used for longer cosmetic effectiveness in lips, nasolabial fold, and malar area (8) etc. Most of the above-mentioned materials-based models are designed to simulate skin, and overall silicone (5) contributes significantly to these models and has a large market share.
However, these materials cannot be used for various other tissues in particular tubular organs such as the oesophagus, trachea, stomach, intestines, urinary bladder, veins, arteries, capillaries, lungs, liver, spleen, bronchi, bronchioles, alveolar ducts, ureters, urethra, fallopian tubes, vas deferens, ejaculatory ducts, umbilical cord, and lymphatic vessels artier etc., which relate to numerous disorders and thus require expert treatment. .
Relatively few low-fidelity simulation (low grade) models are available for simulating tubular organs and with the growing worry about the diseases of the modern world, a vast demand exists to create medical practice models, which simulate close to real tubular constructions situation inside the confinements of a close to real body cavity. Therefore, several types of models have been reported using different materials and processes, for instance.
WO2015189954A1, the document proposes a stratified skin model using transparent polyurethane materials; WO2015177926A1 includes dispersion systems with polyether or polyester polyol and aromatic or aliphatic isocyanate, segmented polyurethane elastomers, and polyurethane foam generated by Polyisocyanate and polyol reactions, with gas generation methods for desired characteristics.
JP2022053963A, the epidermis layer is enriched with diverse synthetic resins like polyurethane, PVC, acrylic, or polyester resins, providing design flexibility. The above polymers have good properties to simulate simple organs or skin but do not provide close to real-life texture or properties needed for making tubular organs; WO 2007/137623 discloses the method for producing a flexible elastomeric multilayer polyurethane skin in which the first layer of polyurethane is formed by spraying polyurethane solution on a Mould and for preparing the second layer, a mixture of aromatic polyurethane is used. After spraying, these layers are cured. US9168684B2, elaborates on making an elastomeric skin by spraying the PVC or paints (acrylic-based material) on a mould. However, the above composition is not suitable for real organ/skin simulation, as on curing it gets hard and stiff.
US2008032272A1 presents a portable surgical practice kit in a portfolio format, having a two-layer suturing pad with latex rubber mimicking skin as the top layer and foam layer as the supporting layer on the downside. However, the above latex-based models are open structure practicing models which do not simulate the stretchability, suturability and collapsibility of real tubular organs. Their latex-based models have higher stiffness, which degrades the suturing experience.
Furthermore, the patent document WO2020041407A1 by Singh Anirudha developed modifying collagen or gelatine by covalently bonding lysine or hydroxylysine residues to aliphatic hydrocarbon chains, which gives sutureable scaffolds for tissue engineering, which can further be used for suturing practice.
Further, various processes and methods are being used to produce the tubular structures and organs along with different compositions of materials such as KR20160118547A and CN114078354A. Various other techniques like fused deposition modeling are being used which creates millimetre- to centimetre-sized biological constructs of multiple cell types using different biomolecules and biomaterials.
However, the internal tubular organs, like the oesophagus, trachea, stomach, intestines, bladder, veins, and urethra, requires lot of practice to perfect surgery skills. This is because these organs have a certain degree of tensile and tear strength along with stretchability, which allows a surgeon to pierce a suturing needle and then form a firm knot without tearing the tissue. This combination of properties provides a certain experience of sutureability. Further, modulus of these tubular organs is low, which allows them to partly collapse under their own weight. This gives a certain level of difficulty in handling a tubular tissue in an operative environment. Use of stiff polymers such as polyurethanes and latexes as tube materials or very soft materials such as silicones as tube materials do not fulfil all of these requirements. Various training devices or models have been tried to offer such practice, yet these models are far away from the real environment and do not simulate a surgical environment with the same difficulty level as in real patients. For example, in patent applications: CN218975027U, JP2005227372A, CN212484721U A, CN105788422B, CN218299248U, CN114038296A, WO2019034008A1, JP4675414B2, EP3219471A1, EP3546499A1 and US2018061279A1.
There are few models for thoracoscopic tracheoesophageal atresia repair reported in the literature. One of the models available for oesophageal atresia training in the market is by the name of Symulus [4]. The above models either use animal tissue that cannot be used for a longer time as the tissue starts smelling and/or provide limited 1 or 2 organs that does not provide the real surgical environment. The collapsible rotatable lungs, Azygous vein, aorta are not provided and the tubular organs do not mimic the feel and texture of human tissue. [ref https://www.resonanceconsulting.co.nz/work/symulus].
Therefore, several models have been developed so far, however the available models have limitation in terms of their utility for a practicing surgeon, such as the (a) use of mostly skin based which do not simulate properties and feel of internal tubular organs; (b) use of hard/stiff materials to simulate a preoperative skill such as intubation, investigative techniques or first aid skills; (c) internal organ models are usually made of very soft water based gels or silicones that do not have enough tearing strength for simulating cutting and suturing skills. Further these models do not provide feel and handling of real tubular tissue, which tends to partially collapse under its own weight.
Further, the main challenge in most of the tubular structures is to attain a combination of properties such as collapsibility, tearing strength, tensile strength, stretchability and recoverability. These properties are required for close to real simulation of the tubular organs. Most of the organ models do not include realistic confined body spaces for simulating endoscopic or thoracoscopic environment, in particular, for paediatric patients. Also, currently no thoracic or abdomen models for simulating abdominal cavity of new born with delicate tubular structure such as oesophagus, trachea, lungs, gastro-intestinal organs, etc is available.
Accordingly, the present invention addresses all these problems as well as limitations and provides a high-fidelity surgical simulating device and model organs for simulating surgical operations on close to real-life tubular and other internal organs. The high-fidelity surgical simulating device developed in the present invention helps the surgeons to practice and gain expertise in an in vitro setting.
OBJECTIVES OF THE INVENTION
One of the objectives of the present invention is to provide a composition for forming model organs for a surgical simulation device.
Another objective of the present invention is to provide a surgical simulation device.
Another objective of the present invention is to develop a process of preparation of a surgical simulation device.
Another objective of the present invention is to provide a process for preparation of model organs for a surgical simulation device.
Another object of the present invention is to develop a high-fidelity, anatomically correct surgical simulation device for simulating surgical operations on close to real-life tubular and other internal organs.
Yet another object of the present invention is to develop a high fidelity, surgical simulation device for tracheoesophageal fistula.
Still another object of the present invention is to develop a method of preparation for high fidelity surgical simulation device for tracheoesophageal fistula.
SUMMARY OF THE INVENTION
This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention nor is it intended to determine the scope of the invention.
Specifically, the present invention provides a composition for forming model organs for a surgical simulation device, comprising:
a) a high molecular weight polymer (HWP), wherein the high molecular weight polymer (HWP) is a polymer having molecular weight in the range of 30000 to 2,000,000 g/mol; and
b) a low molecular weight polymer (LWP), wherein the low molecular weight polymer (LWP) is a polymer having number average molecular weight in the range of 300 to 10000 g/mol.
In another embodiment, the present invention provides a surgical simulation device, comprising:
a) a plurality of model organs prepared from a composition disclosed herein;
b) an outer shell (8) covering the plurality of model organs;
c) a plurality of ports (Y1,Y2,Y3) on the outer shell for inserting thoracoscopic or laparoscopic instruments for simulation surgery; and
d) a base plate (10) with a plurality of pegs (Q,R,S,T, U)adapted to mount the plurality of model organs.
In another embodiment, the present invention provides a process of preparation of the surgical simulation device as disclosed herein, the process comprising:
a) obtaining dimensions of organs of a patient from DICOM images of the patient scans;
b) preparing a plurality of model organs based on the dimensions of the patient scans from composition as disclosed herein;
c) designing a base plate comprising a plurality of pegs to mount the plurality of model organs;
d) arranging the plurality of model organs on the base plate based on patient anatomy to obtain the surgical simulation device.
In another embodiment, the present invention provides a process for preparation of plurality model organs for the surgical simulation device, the process comprising:
a) preparing a solution of high molecular weight polymer (HWP) and a low molecular weight polymer (LWP) in a common solvent, wherein the HWP and the LWP is in a ratio of 99 to 2.33 and wherein the HWP and the LWP has a combined concentration in a range of 5 to 50 wt% in the common solvent;
b) optionally adding one or more additives to the solution at a concentration in the range of 0-10 wt% of the combined concentration of the HWP and the LWP;
c) casting the solution into molds of plurality of organs;
d) removing the solvent from the molds by evaporation by controlled heating or precipitation in a nonsolvent to obtain the model organs;
e) treating the molds by a physical or a chemical process to induce controlled phase segregation to obtain desirable properties of different organs.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
These and other features, aspect, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings are explained in more detail with reference to the following drawings:
Figure 1 (a) illustrates congenital tracheaoesophageal fistula defect of different types. Upper esophagus (1), lower esophagus (2), stomach (3), trachea (4).
Figure 1 (b) illustrates front view of base platform for tracheaoesophageal fistula of Type-C device with pegs (Q,R,S,T,U).
Figure 2 illustrates side view of lung with tracheal opening for oesophageal tracheal fistula Type-C device of tracheoesophageal fistula.
Figure 3 illustrates side open view of Rib Cage attached to platform for oesophageal tracheal fistula device.
Figure 4 illustrates top view of skin/outer shell attached to Rib Cage, having three separate ports for needle holder, Maryland (or a cutter) and endoscopy camera like Y1, Y2, Y3 for oesophageal tracheal fistula Type-C device.
Figure 5 illustrates side view of complete assembly of an embodiment of the stimulation device of the present invention with tubes aorta (11), trachea (4), upper esophagus(1), lower esophagus (2), diaphragm (5), lungs (6) rib cage (12) and skin or outer shell (8,) azygos vein (9) mounted for oesophageal tracheal fistula Type-C device.
Figure 6 illustrates top open view of large intestine (13) and small intestine (14) attached to a platform/base plate for intestine surgery practice device.
Figure 7 illustrates the different layer of skin with artery and vein , skin layer (8), fat layer (15), connecting tissue (16), artery (17), muscle layer (18) peritoneum layer (19).
Figure 8 illustrates the mounting of different tubular organ(19) like oesophagus(1), trachea (4), artery & vein of different capillary sizes (9) and others.
Figure 9 illustrates leaching percentage of LWP1 and its reduction with increasing LWP1 concentration in the solution to control phase separation.
Figure 10 illustrates leaching percentage of LWP1 and its reduction with the addition of metal oxide nanoparticles to control phase separation.
DETAILED DESCRIPTION OF THE INVENTION
Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps of the process, features of the product, referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.
Definitions
For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are collected here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.
The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.
The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”.
Throughout this specification, unless the context requires otherwise the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or step or group of element or steps.
The term “including” is used to mean “including but not limited to”. “Including” and “including but not limited to” are used interchangeably.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.
The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only.
Functionally equivalent products and methods are clearly within the scope of the disclosure, as described herein.
The present invention provides a high-fidelity abdomen cavity surgical simulation device created with close-to-real simulation of tubular internal organs, such as oesophagus, trachea, stomach, intestines, bladder, veins, and urethra, etc. By this device, the surgeons can practice and gain expertise in an in vitro setting. Particularly, the surgeons can master their suturing skills in a confined little space mimicking the space in newborns and then perform it in much less time in live patients, rather than going through the learning curve in real patients and putting them to the risk of prolonged anaesthesia. The high-fidelity device have following benefits and limitations in comparison to actual human cadavers.
Specifically, the present invention provides a composition for forming model organs for a surgical simulation device, comprising:
a) a high molecular weight polymer (HWP), wherein the high molecular weight polymer (HWP) is a polymer having molecular weight in the range of 30000 to 2,000,000 g/mol; and
b) a low molecular weight polymer (LWP), wherein the low molecular weight polymer (LWP) is a polymer having number average molecular weight in the range of 300 to 10000 g/mol.
In another embodiment, the present invention provides a composition for forming model organs for a surgical simulation device, wherein the (HWP) and the (LWP) are soluble in a common solvent, are partially immiscible and partly miscible.
In another embodiment, the common solvent selected from a group comprising water, aqueous NaOH, aqueous KOH, ionic liquids, tetrahydrofuran (THF), dimethyl formamide (DMF), dimethyl acetamide (DMAc), dimethyl sulphoxide (DMSO), acetone, CH2Cl2, ethylene glycol, glycerol, methanol, ethanol, hexane, formic acid, acetic acid, benzene, toluene, m-cresol, n-methyl pyrrolidone (NMP), sulphuric acid and their compatible mixtures optionally with salts such as LiCl, NaCl, CaCl2.
In another embodiment, the present invention provides a composition for forming model organs for a surgical simulation device, wherein the composition comprises one or more additives is selected from a group comprising natural or synthetic textile materials selected from a group comprising fibres, yarns, fabrics, knits and nonwovens of cotton, viscose, polyester, aromatic polyester, nylon, aramids, polyethylene, polypropylene, elastomers, acrylic, polylactic acid, silk, wool, glass, ceramics, high performance materials and their blends thereof, inorganic or organic microfillers, and nanomaterials selected from a group comprising of metals, clay, modified clays, calcium carbonate, carbon nanostructures such as graphene, CNTs, fullerenes, carbon black, carbon nanofibres, inorganic nanostructures, such as TiO2, SiO2, ZnO, MgO, and other metal oxides.
In another embodiment, the present invention provides a composition for forming model organs for a surgical simulation device, wherein the HWP is selected from polyolefins, polyurethane, polyacrylates, polyesters, polyamides, polyacrylonitrile, cellulose, cellulose acetate, triacetates, chitosan, collagen, alginate, polylactic acid, polycaprolactone, PMMA (polymethyl methacrylate), PVC (polyvinyl chloride), PTFE (polytetrafluoroethylene), acrylonitrile-butadiene-styrene (ABS) or their copolymers and mixtures thereof.
In another embodiment, the present invention provides a composition for forming model organs for a surgical simulation device, wherein the LWP is selected from cellulose derivatives such as carboxymethyl cellulose (CMC), hexaethyl cellulose (HEC), guar gum, modified starch, siloxanes, maleic anhydride modified polyolefins, polyether, PEG (polyethylene glycol), polyols, polyvinyl alcohol, polyacrylic acid, polyacrylamide, or their copolymers, their functionalized derivatives, and mixtures thereof.
In another embodiment, the present invention provides a composition for forming model organs for a surgical simulation device, wherein, on weight basis, the high molecular weight polymer (HWP) is in a range of 70 – 99 wt%, low molecular weight polymer (LWP) is in a range of 1-30 wt% and the additive in a range of 0-10 wt%.
In another embodiment, the present invention provides a composition for forming model organs for a surgical simulation device, wherein the HWP and the LWP is in a ratio of 99 to 2.33.
In another embodiment, the present invention provides a composition for forming model organs for a surgical simulation device, the model organs are tubular and other internal organs selected from a group comprising organs of gastrointestinal system, circulatory system, endocrine system, urinary system, reproductive system, lymphatic system, nervous system and integumentary system.
In another embodiment, the present invention provides a composition for forming model organs for a surgical simulation device wherein the organs of the gastrointestinal system, the circulatory system, the endocrine system, the urinary system, reproductive system, lymphatic system, nervous system and the integumentary system are selected from a group comprising arteries, veins, nerves, spinal cord capillaries, bronchi, bronchioles, alveolar ducts, ureters, liver, gallbladder, spleen, fallopian tubes, ovaries, uterus, scrotum, vas deferens, ejaculatory ducts, lymphatic vessels, esophagus, trachea, stomach, diaphragm, intestines, urinary bladder, urethra, kidney, lungs, umbilical cord, azygous vein, tracheoesophageal fistula, esophagus upper part, and oesophagus lower part.
In another embodiment, the present invention provides a surgical simulation device, comprising:
a) a plurality of model organs prepared from a composition disclosed herein;
b) an outer shell (8) covering the plurality of model organs;
c) a plurality of ports (Y1,Y2,Y3) on the outer shell for inserting thoracoscopic or laparoscopic instruments for simulation surgery; and
d) a base plate (10) with a plurality of pegs (Q,R,S,T,U) adapted to mount the plurality of model organs.
In another embodiment, the present invention provides a surgical simulation device, wherein the plurality of model organs are tubular and other internal organs selected from a group comprising organs of gastrointestinal system, circulatory system, endocrine system, urinary system, reproductive system, lymphatic system, nervous system and integumentary system.
In another embodiment, the present invention provides a surgical simulation device, wherein the organs of the gastrointestinal system, the circulatory system, the endocrine system, the urinary system, reproductive system, lymphatic system, nervous system and the integumentary system are selected from a group comprising arteries, veins, nerves, spinal cord capillaries, bronchi, bronchioles, alveolar ducts, ureters, liver, gallbladder, spleen, fallopian tubes, ovaries, uterus, scrotum, vas deferens, ejaculatory ducts, lymphatic vessels, esophagus, trachea, stomach, diaphragm, intestines, urinary bladder, urethra, kidney, lungs, umbilical cord, azygous vein, tracheoesophageal fistula, esophagus upper part, and oesophagus lower part.
In another embodiment, the present invention provides a process of preparation of the surgical simulation device, the process comprising:
a) obtaining dimensions of organs of a patient from DICOM images of the patient scans;
b) preparing a plurality of model organs based on the dimensions of the patient scans from composition as disclosed herein;
c) designing a base plate comprising a plurality of pegs to mount the plurality of model organs;
d) arranging the plurality of model organs on the base plate based on patient anatomy to obtain the surgical simulation device.
In another embodiment, the present invention provides a process of preparation of the surgical simulation device, wherein the plurality of model organs of the surgical simulation device are prepared by a process comprising:
a) preparing a solution of high molecular weight polymer (HWP) and a low molecular weight polymer (LWP) in a common solvent, wherein the HWP and the LWP is in a ratio of 99 to 2.33 and wherein the HWP and the LWP has a combined concentration in a range of 5 to 50 wt% in the common solvent;
b) optionally adding one or more additives to the solution at a concentration in the range of 0-10 wt% of the combined concentration of the HWP and the LWP;
c) casting the solution into molds of plurality of organs;
d) removing the solvent from the molds by evaporation by controlled heating or precipitation in a nonsolvent to obtain the model organs;
e) treating the molds by a physical or a chemical process to induce controlled phase segregation to obtain desirable properties of different organs.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the model organs are prepared by casting, moulding, extrusion, solution spinning, melt spinning, compression or coating.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the common solvent selected from a group comprising water, aqueous NaOH, aqueous KOH, ionic liquids, tetrahydrofuran (THF), dimethyl formamide (DMF), dimethyl acetamide (DMAc), dimethyl sulphoxide (DMSO), acetone, CH2Cl2, ethylene glycol, glycerol, methanol, ethanol, hexane, formic acid, acetic acid, benzene, toluene, m-cresol, n-methyl pyrrolidone (NMP), sulphuric acid and their compatible mixtures optionally with salts such as LiCl, NaCl, CaCl2.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the physical method comprises heating, steaming, moist environment, mechanical action and wherein the chemical method comprises washing, rinsing, sonication in a solvent, dipping in a surfactant solution, or in cold or hot water.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the molds are prepared using casting, 3D printing, moulding, extrusion, compression or coating.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the degree of phase segregation of the two main partly immiscible polymer components, i.e. HWP and LMW, is controlled to obtain desirable properties of the targeted organ.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein elasticity, tensile strength, tearing strength, elastic recovery percentages of model organs are in the range reported for various organs in the literature.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein dimensions of the model organs are similar to the dimensions of the organs as obtained from patients scans or given in the literature.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the patient scans include scans obtained from imaging devices such a MRI, CT, or ultrasonography or patient scans obtained from medical tools including but not limited to an endoscope.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the model organs are prepared by processes known in the art such as casting, 3D printing, moulding, extrusion, compression or coating.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the model organs are tubular and other internal organs selected from a group comprising organs of gastrointestinal system, circulatory system, endocrine system, urinary system, reproductive system, lymphatic system, nervous system and integumentary system.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the organs of the gastrointestinal system, the circulatory system, the endocrine system, the urinary system, reproductive system, lymphatic system, nervous system and the integumentary system are selected from a group comprising arteries, veins, nerves, spinal cord capillaries, bronchi, bronchioles, alveolar ducts, ureters, liver, gallbladder, spleen, fallopian tubes, ovaries, uterus, scrotum, vas deferens, ejaculatory ducts, lymphatic vessels, esophagus, trachea, stomach, diaphragm, intestines, urinary bladder, urethra, kidney, lungs, umbilical cord, azygous vein, tracheoesophageal fistula, esophagus upper part, and oesophagus lower part.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the high molecular weight polymer (HWP) is a polymer having molecular weight in the range of 30000 to 2,000,000 g/mol, wherein the HWP is selected from polyolefins, polyurethane, polyacrylates, polyesters, polyamides, polyacrylonitrile, cellulose, cellulose acetate, triacetates, chitosan, collagen, alginate, polylactic acid, polycaprolactone, PMMA (polymethyl methacrylate), PVC (polyvinyl chloride), PTFE (polytetrafluoroethylene), acrylonitrile-butadiene-styrene (ABS) or their copolymers and mixtures thereof.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the low molecular weight polymer (LWP) is a polymer having number average molecular weight in the range of 300 to 10000 g/mol, wherein the LWP is selected from cellulose derivatives such as carboxymethyl cellulose (CMC), hexaethyl cellulose (HEC), guar gum, modified starch, siloxanes, maleic anhydride modified polyolefins, polyether, PEG (polyethylene glycol), polyols, polyvinyl alcohol, polyacrylic acid, polyacrylamide, or their copolymers, their functionalized derivatives, and mixtures thereof.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein the composition comprises one or more additives is selected from a group comprising natural or synthetic textile materials selected from a group comprising fibres, yarns, fabrics, knits and nonwovens of cotton, viscose, polyester, aromatic polyester, nylon, aramids, polyethylene, polypropylene, elastomers, acrylic, polylactic acid, silk, wool, glass, ceramics, high performance materials and their blends thereof, inorganic or organic microfillers, and nanomaterials selected from a group comprising of metals, clay, modified clays, calcium carbonate, carbon nanostructures such as graphene, CNTs, fullerenes, carbon black, carbon nanofibres, inorganic nanostructures, such as TiO2, SiO2, ZnO, MgO, and other metal oxides.
In another embodiment, the present invention provides a process for preparation of model organs for a surgical simulation device, wherein, on dry weight basis, the high molecular weight polymer (HWP) is in a range of 70 -99 wt%, low molecular weight polymer (LWP) is in a range of 1 -30 wt% and the additive in a range of 0-10wt%.
Table 1 below indicates the benefits and limitations of the various categories of models with a comparison to actual human cadavers.

In the surgical simulation device, the model organs are made using a mixture of a high molecular weight polymer (HWP) and a low molecular weight polymers (LMW) in a proportion to achieve combination of tearing strength, tensile strength, modulus, stretchability (extension), recoverability, cutting and suturing experience. In the case, wherein the two polymers are partially miscible, they are allowed to phase separate by treating the polymers by various physical or chemical methods to simulate close to real life handling experience (with respect to mechanical properties, collapsibility, cutting and tearing properties and suturing properties) of a surgeon. The high molecular weight polymer used in the preparation are the polymers having average molecular weight in the range of 30000 to 2,000,000 g/mol and is selected from the class of polymers, HWP is selected from polyolefins, polyurethane, polyacrylates, polyesters, polyamides, polyacrylonitrile, cellulose, cellulose acetate, triacetates, chitosan, collagen, alginate, polylactic acid, polycaprolactone, PMMA (polymethyl methacrylate), PVC (polyvinyl chloride), PTFE (polytetrafluoroethylene), acrylonitrile-butadiene-styrene (ABS) or their copolymers and mixtures thereof., whereas the low molecular weight polymer used in the preparation is having number average molecular weight in the range of 300 to 10000 g/mol and is selected from the class of polyether, PEG (polyethylene glycol), polyols, polyvinyl alcohol, polyacrylic acid, polyacrylamide, etc. such that the selected polymer is capable of phase separating to a limited degree from the high molecular weight polymer when subjected to physical (such as heating, steam, moist environment, mechanical action, etc.) or chemical treatment (such as washing/rinsing/sonication in a solvent, surfactant solution, cold/hot water, etc.) or combination of the two.
Optionally, the combination of HWP and LWP may have natural or synthetic textile materials, microfillers (inorganic and organic known in the art) or nanomaterials such as clay, carbon nanostructures, inorganic nanostructure to obtain required degree of phase segregation of the LWP an HWP. It has been observed that controlling the degree of phase segregation affects the mechanical (tensile strength, extensibility, recoverability and tear strength) and feel/handle (collapsibility, suturability and elasticity) properties of the obtained tubular model organ.
The above combination of materials are then used for making a variety of tubular model organs such as arteries, veins, nerves, spinal cord capillaries, bronchi, bronchioles, alveolar ducts, ureters, liver, gallbladder, spleen, fallopian tubes, ovaries, uterus, scrotum, vas deferens, ejaculatory ducts, and lymphatic vessels, esophagus, trachea, stomach, diaphragm, intestines, urinary bladder, urethra, kidney, lungs, umbilical cord, azygous vein, tracheoesophageal fistula, esophagus upper part, and oesophagus lower part using polymer processing techniques of solution and melt processing known in the art including but not limited to casting, moulding, extrusion, solution spinning, melt spinning, compression and coating (single and multi-layered coating), etc.
As a particular case, the simulated tubular model organs are placed inside a simulated abdominal cavity to simulate positions of the organs inside a real human body.
In another feature of the device, the abdominal cavities are formed using materials and the processing techniques known in the art. These cavity devices resemble structure and looks of a human body both from the outside and inside.
In another particular case, these simulated abdominal cavities resemble the highly confined spaces observed in neonatals (new born), toddlers and very young children.
In another embodiment, the simulated abdominal cavity with the simulated model organs were placed at an angle at which a surgeon performs an operation to provide close to real life experience during the surgical practice.
The devices of the present invention are fitted with ports in outer shell of the device appropriate for practicing thoracoscopic or laparoscopic surgical skills useful for treating both neonatal and adult patents. Also, the device uses several pegs on which various model organs are mounted to allow stability and limited movement to the various model organs simulating the real surgical situation. Further, the used model organs (those cut and sutured/damaged during practice) can be removed from the pegs and replaced with a new set on the same pegs to allow use of the surgical simulation device multiple times without degrading the surgical experience.
The surgical simulation device can be used for practicing any other operation involving abdominal cavity and tubular organs such as gastrointestinal system, circulatory system (including microsurgery of fine capillaries), endocrine system and urinary system. The compositions of polymers and additives described herein can be used for developing other tubular model organs required for these systems and the abdominal cavity as described can be used to hold various organs belonging to gastrointestinal, circulatory, endocrine and urinary systems with positional change of pegs and changing dimensions of the cavity appropriately for adult, children and neonatal patients.
EXAMPLES
Preparation of Tubular Organs
Tubular model organs of different diameters and lengths were made using various combinations of high molecular weight (HWP) and low molecular weight polymers (LWP). Some of the specific examples with observed properties are given below. The properties were evaluated both objectively using Universal Testing machine (UTM ) (for example mechanical strength, elasticity, modulus,) and subjectively by providing rating from surgeons (experts) on scale of 1 to 5 wherein 1 indicates as poor and 5 indicates as close to real situation. Given the fact that the data for tubular model organs (and that too for neonatals) are scanty, unreliable and also cannot be easily obtained due to ethical considerations, the inventors decided to estimate the necessary properties of related to feel and handle of the various tubular model organs by giving a rating by a team of experienced surgeons. Therefore, a scale of 1-5 was created for accessing and comparing the collapsibility, suturability and elasticity of model organs created using different compositions used in this study.
Table 2: Grade as per remarks from physicians and surgeons in various specialties
Grade Remarks
1 Very poor
2 Poor
3 Average
4 Good
5 Excellent, Close to real
NA Unable to create structures

Table 3: Mechanical properties of different compositions of HWP1, HWP2, HWP3, HWP4, HWP5 and LWP1, LWP2 with or without metal oxides (MO) for tubular organ replication.
Sr. no. Sample name Modulus (MPa) Tensile strength (MPa) Tear strength
(MPa)
1 HWP1-(100-94) LWP1-(0-6) 9.92±2.2 24.32±0.6 7.3±1.1
2 HWP1-(93-85) LWP1-(7-15) 9.76±1.8 23.60±3.4 6.5±1.8
3 HWP1-(84-70) LWP2-(16-30) 7.82±0.6 19.69±2.9 5.2±2.3
4 HWP2-(100-94) LWP1-(0-6) 2.52±2.2 4.32±0.6 0.3±1.1
5 HWP2-(93-85) LWP1-(7-15) 1.56±1.6 3.60±3.4 0.5±0.8
6 HWP2-(84-70) LWP2-(16-30) 1.82±0.6 3.69±2.9 0.2±0.3
7 HWP3-(100-94) LWP1-(0-6) 35.02±4.2 42±2.6 9.2±1.1
8 HWP3-(93-85) LWP1-(7-15) 34.96±4.7 41±3.4 8.5±0.8
9 HWP3-(84-70) LWP2-(16-30) 32.22±2.9 40±2.9 8.2±0.3
10 HWP4-(100-94) LWP1-(0-6) 11.72±0.8 23.28±2.2 11.6±0.5
11 HWP4-(93-85) LWP1-(7-15) 10.33±3.2 21.82±3.4 10.5±2.3
12 HWP4-(84-70) LWP2-(16-30) 7.92±2.5 16.80±2.2 09.1±2.8
13 HWP5-(100-94) LWP1-(0-6) 11.58±1.98 13.30±0.78 9.26±0.45
14 HWP5-(93-85) LWP1-(7-15) 8.80±1.56 9.48±.62 8.50±0.23
15 HWP5-(84-70) LWP1-(16-30) 6.37±1.88 5.95±0.56 6.26±0.79
16 HWP5-(98-80) LWP1-(1-15) MO-(1-5) 12.27±0.60 16.23±2.1 10.28±1.48
17 HWP5-(79-65) LWP1-(16-25) MO-(5-10) 15.86±0.76 18.28±1.2 12.22±1.73
Table 4: Features of tubular organs created using different compositions as assessed by Physicians and Surgeons on a grade scale of 1-5.
Sr. no. Sample name Collapsibility Suturability Elasticity
1 HWP1-(100-94) LWP1-(0-6) 1 1 1
2 HWP1-(93-85) LWP1-(7-15) 2 1 2
3 HWP1-(84-70) LWP2-(16-30) 3 2 2
4 HWP2-(100-94) LWP1-(0-6) 2 2 2
5 HWP2-(93-85) LWP1-(7-15) 3 2 3
6 HWP2-(84-70) LWP2-(16-30) 3 3 3
7 HWP3-(100-94) LWP1-(0-6) 3 2 2
8 HWP3-(93-85) LWP1-(7-15) 3 3 2
9 HWP3-(84-70) LWP2-(16-30) 3 3 3
10 HWP4-(100-94) LWP1-(0-6) 2 3 2
11 HWP4-(93-85) LWP1-(7-15) 3 3 2
12 HWP4-(84-70) LWP2-(16-30) 3 3 2
13 HWP5-(100-94) LWP1-(0-6) 3 4 3
14 HWP5-(93-85) LWP1-(7-15) 4 4 3
15 HWP5-(84-70) LWP1-(16-30) 5 3 3
16 HWP5-(98-80) LWP1-(1-15) MO-(1-5) 5 4 5
17 HWP5-(79-65) LWP1-(16-25) MO-(5-10) 4 4 5

Various types of materials and their compositions in various ratios are utilized to create tubular model organs for medical suturing simulation. Various percentages of low molecular weight (LWP) polymer (300–10,000) and high molecular weight (HWP) polymer (30,000–2,000,000) were utilized to create tubular constructs for internal model organs. In varying formulations, HWP was used in different concentrations of the whole solution (more specifically ranging from 99% to 65%) and LWP in concentration range of 1% to 30% of the total solution in a compatible solvent as per Tables 3 and 4 where HWP1 is cellulose derivative, HWP2 is polyacrylates, HWP3 is polyamides, HWP4 is polyacrylonitrile, and HWP5 is polyurethane. Lower molecular weight polymers LWP1 is polyethylene glycol, LWP2 is polyvinyl alcohol and LWP3 is polyacrylic acid. The solutions were cast into tubes of various sizes. The solution cast tubes were heat treated at temperatures of 40-80 degree C for 30 minutes to 4 hours to allow evaporation of the solvent followed by controlled phase segregation, which results in final tubular membranes with properties as mentioned below. Alternately, the tubes were treated with warm water (50-90 degree C) for 1 min-10 min as per leaching percentage to allow limited phase segregation. Without the physical or chemical treatment, the properties of tubular membrane were unstable and non-reproduceable.
Properties:
Table 3 gives mechanical properties in terms of modulus, tensile strength and tearing strength of different compositions. Table 4 gives comparison of properties such as collapsibility, suturability and elasticity of different compositions as assessed by various physicians and surgeons on graded scale of 1 to 5. As can be seen that specific combination yield different combination of properties and hence can be used for different tubular organs having different characteristics. For example, collapsible tubular organs such as oesophagus can have proportions where the collapsibility grades are 4-5, whereas trachea can be made using compositions where the collapsibility grade is 2-3.
In a few trials, the proportion of HWP5 was kept constant in the range of 84-70%, while the percentage of LWP1 was varied between 16 and 30%. This improved the homogeneity of tubular model organs with a good collapsibility value; however, the suturing experience did not replicate that of actual organ. Collapsibility and flexibility should be in the desirable ranges (of 5 grade for collapsibility) and (4-5 grade for flexibility) (Table 4) for a better suturing experience. Therefore, the HWP5 percentage was reduced, with introduction of metal oxides (MO), with concentration up to (1-5%). The better grades of collapsibility (5 grade), suturability (4 grade) and elasticity (5 grade) were obtained with 98-80% HWP5 and 1-15% LWP1 and MO 1-5%. As the percentage of LWP1 was increased to 16–25% and MO with 5-10%, the grades were given as- collapsibility (4), suturability (4 grade) and elasticity (5 grade).
The tensile properties like modulus and tensile strength of different samples were measured using INSTRON 3365,. where Young’s modulus of HWP5(100-94), LWP1(0-6), HWP5(93-85) LWP1(7-15), HWP5(84-70) LWP1(16-30) were 11.58±1.98, 8.80±1.56 and 6.37±1.88 MPa and tensile strength values of 13.30±0.78, 9.48±0.62 and 5.95±0.56 MPa, respectively. Elastic recovery percentages of the above-mentioned samples were in the range of 72-97% values for HWP5(100-94) LWP1(0-6), HWP5(93-85) LWP1(7-15), HWP5(84-70) LWP1(16-30) but these values dropped as the concentrations of HWP5 were higher, for example for HWP5 (100-94) but the recovery was poor at about 72%-83%. These values of modulus and tensile strength were compared to those of tubes reported in the prior art. The rubber tube, latex tube, and silicone tubes had either very low or very high values of Young’s modulus and tensile strength with poor recovery from high deformative strains.
The tensile properties were also measured (Table 3) for formulations with addition of metal oxides (MO), where Young’s moduli of HWP5(98-80) LWP1(1-15) MO-(1-5), HWP5(79-65) LWP1(16-25) MO-(5-10) were found to be 12.27±0.60 and 15.86±0.76 MPa and Tearing strength values were found to be 10.28±1.48, and 12.22±1.73 MPa, respectively.
A variety of other polymers with varying molecular weight ranges were tried as HWP and LWP, including polyurethane (ether-based), polyurethane (ester-based), PMMA (polymethyl methacrylate), PVC (polyvinyl chloride) as HWP, while PEG (polyethylene glycol), polyacrylic acid, polyethylene oxide (PEO), polyols as LWP.
Limited data is available in the literature (34) for human oesophagus (for 2 years child to 22 years adult). Diameter and mechanical properties like modulus, tensile strength, tear strength vary with age group and geographical location. As per the available literature, oesophagus and trachea have a broad range of modulus, tensile strength and tearing strength as given in Table 5. Since the data for such organs (specially for neonatals) are scanty, unreliable and also cannot be easily obtained due to ethical considerations, it is important to estimate the properties with the feel and handle provided by a team of experienced surgeons. This is the reason that a scale of 1-5 was created for accessing the collapsibility, suturability and elasticity of different compositions to arrive at a model that is close to a realistic situation experience by a surgeon.
Based on the data of Tables 3 and 4, the inventors find that compositions based on HWP5 and LWP1 with inclusion of MO show properties that are close to values seen for actual organs. Further they provide better feel, texture and handle as estimated by the experienced surgeons. Therefore, these compositions are suitable for cutting and suturing practices.
Table 5: Mechanical properties of oesophagus and trachea for humans of age group 2-22 years.
Organ Modulus
(MPa) Tensile strength (MPa) Tearing strength
(MPa)
Oesophagus 5-20 1-5 0.5-2.0
Trachea 5-30 2-10 0.8-4.0

Phase separation study:
The leaching rate of polymeric materials is significantly influenced by the concentration of LWP1 in the total polymer weight. Higher concentrations of LWP1 (18-22) result in a lower leaching percentage, typically ranging between 36% to 63%, whereas lower concentrations LWP1 (0-6) lead to increased leaching, ranging from 52% to 84%. Additionally, the duration of phase separation plays a crucial role in determining the final composition and leaching extent. A longer phase separation time, such as increasing from 1 minute to 5 minutes, results in a 30-40% increase in leaching as per Figure 9.
Furthermore, the storage duration before phase separation impacts leaching behaviour, with materials stored for one week exhibiting an increased leaching percentage by approximately 20-30% as per Figures 9 and 10. To mitigate leaching, the incorporation of nanoparticles of different metal oxides (MO), has been found to effectively inhibit phase separation and maintain material integrity. The addition of approximately 1% nanoparticles can reduce the leaching percentage by 3-5% as per Figure 10. In phase separated samples (with treatment time of 1-10 minutes), there was an increment in Tensile Modulus by about 11-19% and in Tearing strength by about 7-21%.
Development of Neonatal Thoracoscopic Model
Using the above tubes, adult and neonatal thoracoscopic model organs have been created. For example, an adult model organ has been created for general thoracoscopic surgery for airway fistula. However, neonatal surgeries are more challenging as the chest space is very confined and a surgeon has to perform the procedures with limited movement of tools and in shortest possible time. Therefore, the present invention provides a detailed description of a neonatal surgical simulation device created using tubular model organs made using the above compositions.
The Neonatal surgical simulation device was created for TFE abnormality, i.e. Esophageal atresia with tracheoesophageal fistula, which is a congenital condition in which the food pipe is not formed completely, is rather blind ended and the lower part of the Oesophagus (food pipe) is connected to the trachea (windpipe). The condition is life threatening as the baby cannot take anything by mouth and if given by mistake the milk goes to the chest and causes pneumonia. The condition needs immediate repair, once the chest condition of the baby is stable. The operation involves dividing the fistula and perform the anastomosis (suture together) of the two ends of Oesophagus. As mentioned above, this complex medical disorder, tracheoesophageal fistula (ETEF), is defined by an improper connection between the trachea and the oesophagus. Food and air cannot move through this abnormality normally, which can cause serious digestive and respiratory issues. This frequently results from trauma, underlying medical disorders, extended intubation, or congenital abnormalities. To determine the extent of the fistula and any related anomalies, diagnostic procedures frequently entail imaging scans and endoscopic assessments. Surgical procedures and conservative approaches to management differ based on the underlying reasons and severity. To reduce risks and enhance patient outcomes, early detection and management are essential.
Medical model organs are crucial in helping physicians get the knowledge and abilities necessary to treat complicated diseases such as esophageal tracheal fistula. With the help of such realistic illustrations of anatomical structures and diseases, doctors can conduct a range of diagnostic and therapeutic techniques in a safe setting. Medical model organs instill confidence, competence, and decision-making skills in physicians by modeling the difficulties that arise in managing such abnormalities. They also provide a secure learning environment for trainees without endangering patient safety. In the end, the use of medical mode organs s promotes improved patient care by guaranteeing that medical professionals are suitably equipped to handle difficult clinical situations.
Description of example models:
Tubular organs in the human body include various structures across multiple systems. In the circulatory system, arteries, veins, and capillaries serve as blood vessels transporting oxygen and nutrients. The respiratory system contains the trachea, bronchi, bronchioles, and alveolar ducts, facilitating airflow and gas exchange. The digestive system features the esophagus, small intestine, and large intestine, aiding in digestion and nutrient absorption. The urinary system consists of the ureters and urethra, allowing urine to be transported from the kidneys to the bladder and then out of the body. The reproductive system uses the fallopian tubes in females to move eggs from ovaries to the uterus, and the vas deferens, scrotum, and ejaculatory ducts in males transport sperm. Lastly, lymphatic vessels in the lymphatic system facilitate immune function by circulating lymph fluid were made using the above examples to simulate their close to real life handling. Oesophageal tubes were made of various compositions to get the ideal tissue and dimensions. Tracheal tube was made with a thicker and stiffer composition with collapsibility Grade 2-3 tissue. Azygous vein was made of highly collapsible (grade 5) thin material. Intestine were made of highly collapsible (grade 5). Once the tissue quality and sizes were finalized by trials, the work on the thorax was started. The DICOM images of an infant CT scan were studied. These were then converted to a stl. format using 3D Slicer. Designing of the surgical simulation device was done by taking the right hemithorax and designing a base as a sagittal divider between the thorax. For the neonatal size, three newborn babies’ chest and spine measurements were taken and an average was calculated. The dimensions of the model were designed accordingly. The skin was made of tissue mimicking a baby skin and taking the contour of a baby chest with a raised arm thus mimicking the position of the baby while such an anomaly is operation upon in the operation theatre.
In developing the surgical simulation device for oesophageal tracheal fistula abnormality, first a base plate was prepared for efficient mounting of various organs, such as diaphragm, lungs, ribcage, trachea tube, azygos vein, oesophagus upper part and oesophagus lower part. The tubular structures were made using the above examples to simulate their close to real life handling. The base was created with dimensions (approx. 20-30 cm x 12-15 cm). The base platform was tilted at an angle, with a mechanism that allowed angle to change in the range of 10-45 degree to simulate a real baby position during the surgery.
To hold the various model organs, several pegs were also built with the base plate shown as Q, R, S, T, U. To hold the hollow lung structure (cone shaped tubular structure), a rod of length 8 cm was created close to the base plate (0.5 to 2 cm from the base). This allowed slight movement and a limited degree of rotation of the lung around the rod. Other mountings of tubular model organs like the azygos vein was placed using two pegs Q and R. In the Oesophageal Tracheal Fistula, the upper part of the model oesophagus was mounted at peg S, and its lower end was kept closed with a length of 2-10 cm. Peg S had a small hole to allow insertion of model feeding tube to assist during the joining of two model oesophagus parts simulating an actual operation. The lower part of the model oesophagus was connected to the model trachea on one side and the other end was connected to peg T. The transparent model trachea tube was connected at peg U on the upper side and it goes into the model lung at the other end. The platform with different pegs is shown in Figure 1(b) described herein in the specification.
A tube of 8 cm in length attached to a diaphragm shaped plate gives stability to model lungs and allows rotation of the model lung during the surgery practice. This model lung structure has a hole which allows model trachea to be inserted. This model lung structure is of length of about 6-10 cm, it is closed at the narrow end and is cone shaped with a diameter of about 4-8 cm at the other larger end. The model trachea opening is on the upper half side of the model lung as shown in Figure 2 described herein in the specification. The compositions used is such that the model lung can hold its structure yet can be collapsed by putting small pressure. It regains its shape after the force is removed. This simulates a real lung behaviour in a living body. The composition used for this tubular model lung structure has higher elasticity of Grade 4-5.
The vertebral side of the hemithorax was connected by a hinge to a flat base that formed one wall of a triangular prism. This allowed easy lifting of the model rib structure to one side to allow access for replacing the used organs. The model rib cage was of dimensions about 12-20 cm in length as shown in Figure 3 described herein in the specification with a height of 7-10 cm range as per different age groups.
The model rib cage was about 7-11 cm wide as shown in Figure 3 which is the side view of the structure. All these parts were made using polymers such as polylactic acid and using known techniques such as 3D printing, moulding or/and machining.
This model rib cage is covered with model skin and outside body structure /outer shell of about (4-40 mm thick) made up of different materials like polyurethane, silicone, collagen, and polyvinylchloride. Skin and outside body structure can be created with different techniques like moulding and 3-D printing.
A baby mould as shown in Figure 4 is created to cover the drawing model rib cage shown earlier in Figure 3. Three holes or ports with circular diameters in a range of 2-7 mm are created as shown and point with Y1, Y2, and Y3. After attaching the model skin over the model rib cage, the model lung and model tubular organs (oesophagus, trachea, azygos vein) were mounted as described in Figure 1(b). Figure 5 shows the different views of model tubes and model lung mounting. These model tubular organs were made using compositions mentioned in the above Tables 3 and 4.
Additionally, model aorta can be placed close to these model organs to simulate presence of other critical organs near the operation site.
The lower end of the model oesophageal is connected to model trachea and model trachea is inserted inside the hole made in the model lung structure. All these pegs used for mounting gives stability to the different model organs so that they have limited movement as required during the practicing procedure. Further, after the model organs have been cut/sutured or damaged during the training session, these pegs can be used again for mounting a new set of model organs. This can be done repeatedly for many-many practicing sessions.
This can serve as a training device for acquiring the refined skills needed for the advanced thoracoscopic surgery of tracheoesophageal atresia repair. Training on this surgical simulation device will help to improve patient safety, reduced morbidity and mortality.
This can be used as an open model and can be used as bigger cavity model by opening the model and placing it in a laparoscopic simulator.
Figure 6 provides a structural representation of tubular organs, namely the small and large intestines. The larger structure, such as the large intestine, illustrates a segmented, haustral-like surface morphology, while the smaller, cylindrical tube illustrates the small intestine. The structure mimics the anatomical and mechanical characteristics of human intestines and is thus useful for medical simulation, surgical training, and research experiments. Figure 7 provide different layers of skin with vein and artery structure.
Figure 8 presents a structural model of tubular organs equivalent to components of the circulatory, reproductive, and lymphatic systems. The model consists of flexible and rigid tubes that mimic various anatomical structures, such as arteries, veins, capillaries, bronchi, bronchioles, alveolar ducts, ureters, urethra, fallopian tubes, vas deferens, ejaculatory ducts, and lymphatic vessels. The tubular construct structure is designed to mimic the inherent elasticity, curvature, and fluid transport characteristics of real biological tissues. Sealed in a supporting structure, the model allows for precise positioning, and is thus suitable for use in surgical training, medical research, and device testing. The materials used exceed the composition levels of HWP1-5 and LWP1-2, and include the metal oxides (MO) as described.
Advantages
• The surgical simulation device of the present invention helps the surgeons practice and gain expertise in an in vitro setting. Particularly, the surgeons can master their suturing skills in a confined little space mimicking the space in newborns and then perform it in much less time in live patients, rather than going through the learning curve in real patients and putting them to the risk of prolonged anesthesia.
• The surgical simulation device of the present invention has unique properties and has an opening mechanism (i.e. hinged ribcage) that can allow usage in a wider space for the initial learning.
• The surgical simulation device of the present invention is made up of synthetic material that is friendly to the human skin. Further, it can be stitched easily with fine suture material.
• The surgical simulation device of the present invention has the needed collapsibility, tear strength and elasticity mimicking real tubular model organs such as trachea, esophageal tissue, and veins, etc. The size of the simulated model organs (oesophagus and trachea, etc.) is same as in a newborn child thus giving the opportunity in a high-fidelity model.
• The surgical simulation device of the present invention can serve as a training device for acquiring the refined skills needed for advanced thoracoscopic surgery of tracheoesophageal atresia repair. Further, training on this model will help to improve patient safety, reduced morbidity and mortality.
• The surgical simulation device of the present invention can be used as an open model and can be used as bigger cavity-based model by opening the model and placing in a laparoscopic simulator.
• The surgical simulation device of the present invention can be used for practicing any other operation involving abdominal cavity and tubular organs such as gastrointestinal system, circulatory system, endocrine system and urinary system as the compositions described herein can be used for developing other tubular model organs and the model abdominal cavity as described can be used to hold various organs belonging to gastrointestinal, circulatory, endocrine and urinary systems with positional change of pegs and changing dimensions of the cavity appropriately.
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35. US2018061279A1, Hydrogel Structure, Blood Vessel, Internal Organ Model, Practice Tool for Medical Procedure, And Method of Manufacturing the Hydrogel Structure, Niimi Tatsuya ,CLAIMS:1. A composition for forming model organs for a surgical simulation device, comprising:
a) a high molecular weight polymer (HWP), wherein the high molecular weight polymer (HWP) is a polymer having molecular weight in the range of 30000 to 2,000,000 g/mol; and
b) a low molecular weight polymer (LWP), wherein the low molecular weight polymer (LWP) is a polymer having number average molecular weight in the range of 300 to 10000 g/mol.
2. The composition as claimed in claim 1, wherein the composition comprises one or more additives is selected from a group comprising natural or synthetic textile materials selected from a group comprising fibres, yarns, fabrics, knits and nonwovens of cotton, viscose, polyester, aromatic polyester, nylon, aramids, polyethylene, polypropylene, elastomers, acrylic, polylactic acid, silk, wool, glass, ceramics, high performance materials and their blends thereof, inorganic or organic microfillers, and nanomaterials selected from a group comprising of metals, clay, modified clays, calcium carbonate, carbon nanostructures such as graphene, CNTs, fullerenes, carbon black, carbon nanofibres, inorganic nanostructures, such as TiO2, SiO2, ZnO, MgO, and other metal oxides.
3. The composition as claimed in claim 1, wherein the (HWP) and the (LWP) are soluble in a common solvent, are partially immiscible and partly miscible.
4. The composition claimed in claim 1, wherein the HWP is selected from polyolefins, polyurethane, polyacrylates, polyesters, polyamides, polyacrylonitrile, cellulose, cellulose acetate, triacetates, chitosan, collagen, alginate, polylactic acid, polycaprolactone, PMMA (polymethyl methacrylate), PVC (polyvinyl chloride), PTFE (polytetrafluoroethylene), acrylonitrile-butadiene-styrene (ABS) or their copolymers and mixtures thereof.
5. The composition as claimed in claim 1, wherein the LWP is selected from cellulose derivatives such as carboxymethyl cellulose (CMC), hexaethyl cellulose (HEC), guar gum, modified starch, siloxanes, maleic anhydride modified polyolefins, polyether, PEG (polyethylene glycol), polyols, polyvinyl alcohol, polyacrylic acid, polyacrylamide, or their copolymers, their functionalized derivatives, and mixtures thereof.
6. The composition as claimed in claim 2, wherein the high molecular weight polymer (HWP) is in a range of 70 – 99 wt%, low molecular weight polymer (LWP) is in a range of 1 -30 wt% and the additive in a range of 0-10 wt% .
7. The composition as claimed in claim 1, wherein the HWP and the LWP is in a ratio of 99 to 2.33.
8. A surgical simulation device, comprising:
a) a plurality of model organs prepared from a composition as claimed in claims 1 to 7;
b) an outer shell (8) covering the plurality of model organs.
c) a plurality of ports (Y1,Y2,Y3) on the outer shell for inserting thoracoscopic or laparoscopic instruments for simulation surgery; and
d) a base plate (10) with a plurality of pegs (Q,R,S,T,U) adapted to mount the plurality of model organs.
9. The device as claimed in claim 8, wherein the plurality of model organs are tubular and other internal organs selected from a group comprising organs of gastrointestinal system, circulatory system, endocrine system, urinary system, reproductive system, lymphatic system, nervous system and integumentary system.
10. The device as claimed in claim 8, wherein the organs of the gastrointestinal system, the circulatory system, the endocrine system, the urinary system, reproductive system, lymphatic system, nervous system and the integumentary system are selected from a group comprising arteries, veins, nerves, spinal cord capillaries, bronchi, bronchioles, alveolar ducts, ureters, liver, gallbladder, spleen, fallopian tubes, ovaries, uterus, scrotum, vas deferens, ejaculatory ducts, lymphatic vessels, esophagus, trachea, stomach, diaphragm, intestines, urinary bladder, urethra, kidney, lungs, umbilical cord, azygous vein, tracheoesophageal fistula, esophagus upper part, and oesophagus lower part.
11. A process of preparation of the surgical simulation device as claimed in claims 8 to 10, the process comprising:
a) obtaining dimensions of organs of a patient from DICOM images of the patient scans;
b) preparing a plurality of model organs based on the dimensions of the patient scans from composition as claimed in claims 1 to 7;
c) designing a base plate comprising a plurality of pegs to mount the plurality of model organs;
d) arranging the plurality of model organs on the base plate based on patient anatomy to obtain the surgical simulation device.
12. The process as claimed in claim 11, wherein the plurality of model organs are prepared by a process comprising:
a) preparing a solution of high molecular weight polymer (HWP) and a low molecular weight polymer (LWP) in a common solvent, wherein the HWP and the LWP is in a ratio of 99 to 2.33 and wherein the HWP and the LWP has a combined concentration in a range of 5 to 50 wt% in the common solvent;
b) optionally adding one or more additives to the solution at a concentration in the range of 0-10 wt% of the combined concentration of the HWP and the LWP;
c) casting the solution into molds of plurality of organs;
e) removing the solvent from the molds by evaporation by controlled heating or precipitation in a nonsolvent to obtain the model organs;
f) treating the molds by a physical or a chemical process to induce controlled phase segregation to obtain desirable properties of different organs.
13. The process as claimed in claim 12, wherein the model organs are prepared by casting, moulding, extrusion, solution spinning, melt spinning, compression or coating.
14. The process as claimed in claim 12, wherein the common solvent selected from a group comprising water, aqueous NaOH, aqueous KOH, ionic liquids, tetrahydrofuran (THF), dimethyl formamide (DMF), dimethyl acetamide (DMAc), dimethyl sulphoxide (DMSO), acetone, CH2Cl2, ethylene glycol, glycerol, methanol, ethanol, hexane, formic acid, acetic acid, benzene, toluene, m-cresol, n-methyl pyrrolidone (NMP), sulphuric acid and their compatible mixtures optionally with salts such as LiCl, NaCl, CaCl2.
15. The process as claimed in claim 12, wherein the physical method comprises heating, steaming, moist environment, mechanical action and wherein the chemical method comprises washing, rinsing, sonication in a solvent, dipping in a surfactant solution, or in cold or hot water.
16. The process as claimed in claim 12, wherein the molds are prepared using casting, 3D printing, moulding, extrusion, compression or coating.
17. The process as claimed in claim 12, wherein the high molecular weight polymer (HWP) is a polymer having molecular weight in the range of 30000 to 2,000,000 g/mol, wherein the HWP is selected from polyolefins, polyurethane, polyacrylates, polyesters, polyamides, polyacrylonitrile, cellulose, cellulose acetate, triacetates, chitosan, collagen, alginate, polylactic acid, polycaprolactone, PMMA (polymethyl methacrylate), PVC (polyvinyl chloride), PTFE (polytetrafluoroethylene), acrylonitrile-butadiene-styrene (ABS) or their copolymers and mixtures thereof.
18. The process as claimed in claim 12, wherein the low molecular weight polymer (LWP) is a polymer having number average molecular weight in the range of 300 to 10000 g/mol, wherein the LWP is selected from cellulose derivatives such as carboxymethyl cellulose (CMC), hexaethyl cellulose (HEC), guar gum, modified starch, siloxanes, maleic anhydride modified polyolefins, polyether, PEG (polyethylene glycol), polyols, polyvinyl alcohol, polyacrylic acid, polyacrylamide, or their copolymers, their functionalized derivatives, and mixtures thereof.
19. The process as claimed in claim 12, wherein one or more additives is selected from a group comprising natural or synthetic textile materials selected from a group comprising fibres, yarns, fabrics, knits and nonwovens of cotton, viscose, polyester, aromatic polyester, nylon, aramids, polyethylene, polypropylene, elastomers, acrylic, polylactic acid, silk, wool, glass, ceramics, high performance materials and their blends thereof, inorganic or organic microfillers, and nanomaterials selected from a group comprising of metals, clay, modified clays, calcium carbonate, carbon nanostructures such as graphene, CNTs, fullerenes, carbon black, carbon nanofibres, inorganic nanostructures, such as TiO2, SiO2, ZnO, MgO, and other metal oxides.