Classifications

• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
  • G09B23/00—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
  • G09B23/28—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine
  • G09B23/286—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine for scanning or photography techniques, e.g. X-rays, ultrasonics

Definitions

• This invention relates to a mannequin device for training medical practitioners in ultrasound guided percutaneous surgery procedures.
• Ultrasound-guided (or sonography-guided) medical procedures allow minimally invasive percutaneous treatments like guided injections of various drugs and medications (including saline in hydrodissection procedures), needling (multiple punctures of some internal tissue, usually a degenerated tendon), cutting tissues like the transverse carpal ligament in carpal tunnel syndrome, the annular pulley in trigger finger, the chord of Dupuytren, a degenerated tendon in for example lateral epicondylitis, or retrieving some foreign or biological body.
• Mannequins Physical models of the human body or parts of the human body, also known as mannequins, are used for training in the medical field. Mannequins representing the human normal or pathological anatomy may present for instance coloured tissues of complex geometry, and additive manufacturing facilitates the production of models which may include unique pathological abnormalities. Mannequins are known for training minimally invasive percutaneous procedures, such as for instance practicing venous puncture. In conventional models, although the skin may be simulated reasonably well for haptic feedback to train for vein localization and puncture, many other anatomical components are not replicated or configured optimally to allow specifically training complex ultrasound guided percutaneous procedures, such as carpal tunnel syndrome treatment, in a realistic manner.
• the mannequin model replicates with high fidelity a region of human anatomy of interest as well as the physical and echogenic characteristics of each tissue of interest.
• Such model may replicate healthy structures and tissues as well as tissues presenting abnormal shape, volume, mechanical properties or echogenicity, configured to simulate diseases or the presence of foreign bodies or tumors.
• a mannequin for ultrasound guided surgical training comprising an artificial bone structure comprising a surface portion reflecting ultrasound waves, artificial tissues comprising any one or more of artificial ligaments, artificial tendons, artificial nerves, artificial blood vessels formed of a material having a partial transparency and partial reflectance to ultrasound waves, and anechoic material surrounding said artificial tissues and artificial bone structure, and an artificial skin formed of an elastomeric layer of material enveloping the anechoic medium.
• the mannequin further comprises a support structure on which the artificial bone structure is fixed or integrally formed with, the support structure comprising elements configured for anchoring artificial ligaments and optionally any one or more of artificial nerves, artificial blood vessels and artificial tendons assembled to the artificial bone structure.
• the artificial nerves and or artificial blood vessels comprise materials comprising or consisting of plant-based food derivatives.
• the artificial nerves and/or artificial blood vessels are coated by a layer of latex or silicone elastomer configured to enhance contrast on sonography and mechanical resistance.
• the plant-based food derivatives are processed from cereals or rice or beans.
• the material forming the artificial skin comprises or consists of latex or silicone elastomer.
• the anechoic material comprises or consists of a hydrophilic colloid.
• the hydrophilic colloid is agar agar.
• the artificial bone structure comprises artificial bones made of a material comprising or consisting of a thermoplastic or thermosetting polymer.
• the artificial bone structure comprises artificial bones made of a material comprising or consisting of a biodegradable polymer such as polylactide (PLA).
• the artificial bone structure comprises artificial bones made of a material comprising or consisting of plaster (gypsum).
• the mannequin further comprises artificial subcutaneous/interstitial tissues formed of hypoechoic materials.
• hypoechoic material comprises or consists of a hydrophilic colloid for instance agar agar.
• the mannequin further comprises artificial fat tissue the material of the fat tissue comprising or consisting of a cereal, rice or bean milled product, for instance wheat semolina.
• the artificial ligaments are made of a material comprising or consisting of polyester or cellulose, or both polyester and cellulose.
• the mannequin is a hand mannequin.
• Figure la and lb are schematic perspective views of an artificial bone structure on a base wall of a support, of a hand mannequin according to an embodiment of the invention
• Figures 2a and 2b are schematic perspective views of abase of the support for producing a hand mannequin according to an embodiment of the invention
• Figure 3 is a schematic perspective view of a cover of the support with a negative imprint of a bottom side of a hand for producing a hand mannequin according to an embodiment of the invention
• Figures 4a to 4e are schematic perspective views of the support and cover showing different steps in producing a hand mannequin according to an embodiment of the invention
• Figures 5a and 5b are photographic views of the support and cover showing different steps in producing a prototype hand mannequin according to an embodiment of the invention
• Figures 6a and 6b are photographic views of the support and cover showing further steps in producing a hand mannequin according to an embodiment of the invention
• Figures 7a and 7b are photographic views of the manufactured prototype mannequin according to an embodiment of the invention, figure 7a showing the mannequin prior to training and figure 7b showing the hand mannequin with a section of artificial skin cut open.
• a physical model of a body part 2 according to an embodiment of the invention will be described in more detail.
• the mannequin that is illustrated is a hand mannequin intended for training ultrasound guided surgical procedures on the hand.
• Such surgical procedures may for instance include carpal tunnel surgery (release of transverse carpal ligament), trigger fmger/thumb surgery (release of annular pulleys), de Quervain surgery (opening of first extensor compartment that can be subdivided in two subcompartments), Dupuytren surgery (release of retractile fibrous subcutaneous chords) percutaneous treatment of dorsal or palmar wrist or hand ganglion.
• the first is the correct echogenicity properties of the materials forming the mannequin in at least the portions of mannequin that are relevant or of interest for the surgical procedures.
• the second are the properties of cutting and resistance to the movement of the surgical tools to provide accurate realistic haptic feedback to the trainee, such properties being provided at least over the portion of the mannequin engaged by the surgical tools.
• the geometry of the anatomical structures forming the mannequin may be obtained by computer tomography (CT) scans, magnetic resonance imaging (MRI) or other per se known scanning techniques used for modelling body parts in three dimensions.
• CT computer tomography
• MRI magnetic resonance imaging
• the artificial anatomical structures of the mannequin includes a skin model 6, a bone structure model 8, a nerve model 10, a blood vessel model 12, a ligament model 14, a muscle tissue model 16, a fat tissue model 18 and a subcutaneous / interstitial tissue model 20.
• Artificial anatomical structures may further include pathological site models such as a tumor model and a ganglion model. It may be noted that not all of the above models are necessarily present in a mannequin, this depending on the location of the body part and the specific surgical procedures to be carried out.
• the surgical training system will further comprise an ultrasound system with an ultrasound probe and a computing station with a display connected to the ultrasound probe.
• the trainee manipulates an invasive medical tool, in particular a percutaneous medical tool that the trainee guides in the mannequin using the ultrasound system.
• the system for producing the mannequin may include a manufacturing system that receives a digital anatomy model from a computing system, obtained for instance by a scan of a body part on a physical person.
• the mannequin may be a free standing portion of a body part or may comprise a support structure 4 on which the anatomical structures are mounted.
• the support structure 4 may serve as a support for handling of the anatomical structures during the manufacturing process.
• the support structure may also provide a protective function for the anatomical structures during transport, handling, and storage.
• the support structure comprises a base wall 4a that may be inserted / mounted in a base 4b, for instance in the form of an open box, and optionally a cover 4c, it being understood however that any other support structure shapes may be provided depending on how it is intended to handle, transport and store the mannequin as well as the manner in which the mannequin is used and supported during the training operation, whereby the support structure is configured to allow access by the trainee in simulated realistic conditions.
• the bone structure model 8 replicates the 3D geometry of real bones, comprises or consists of, at least for the surface of the artificial bones, a material reflecting ultrasound in a similar manner to the ultrasound reflection properties of real bones.
• a material reflecting ultrasound in a similar manner to the ultrasound reflection properties of real bones.
• the portions of bone structure not intended to reflect ultrasound may be made of various materials without regard to their echogenicity properties, and for instance supported on a flat stable basis, possibly in a box facilitating moulding of the materials representing the other tissues.
• PLA Polylactic acid
• TPU Thermoplastic polyurethane
• PETG Polyethylene terephthalate glycol
• SGFR short glass fibre reinforced epoxy resin or plaster (gypsum) that can be moulded.
• a biodegradable polymer such as polylactide (PLA) may be used to make the artificial bones.
• PLA provides the advantage of being recyclable and well adapted for additive manufacturing, if this mode of production is chosen.
• bone structure models made of several adjacent artificial bones they can be conveniently fused if this facilitates the general stability of the model.
• a tubular shape of material is provided, the material behaving echogenicity properties that moderately reflect the ultrasound, allowing a sonographic image resembling the honeycomb fascicular structure in transverse and longitudinal nerve views.
• Materials selected moderately reflecting ultrasound include plant based food derivatives with a controlled humidity.
• the materials for nerves may be derived from flour of wheat (protein : 10-13% carbohydrate: 60-70%, Fat: 1-2%, Fibers: 2-3%) rice (protein :2-3% carbohydrate: 25-35%, Fat:0,5-l%, Fibers: 0,7%) or mung bean (protein :0,5% carbohydrate: 80-85%, Fat:0,5%).
• Cereals or rice processed derivatives that may for instance be obtained from the food industry are biodegradable and allow a good representation of neural structures.
• these materials are coated by a thin layer of latex or silicone elastomer to create an interface between them that will reflect echos and better define the limit between two tendons or two nerve fascicles for example. This coating gives also some stiffness to these structures allowing the trainee to feel some resistance while introducing a puncture needle or cutting device.
• mannequin containing biodegradable materials such as food derivatives may be extended with the addition of salt or antiseptics, or as alternative or in addition the mannequin may be stored in a packaging filled with a neutral gas such as nitrogen, and/or the mannequin may be stored in a fridge or deep freezer.
• a neutral gas such as nitrogen
• Plant based food derivatives similar to the materials used for nerves may also be advantageously used to represent blood vessels, the material formed into tubular shapes replicating the geometry of real blood vessels.
• hollow pasta with a controlled humidity to provide suppleness may be filled by a coloured liquid, allowing the trainee to carry out a dissection, at the end of the sonoguided procedure, to verify if the artery or vein is intact or has been injured during the procedure.
• These materials may advantageously be coated by a thin layer of latex or silicone elastomer that creates an interface that reflects echos and better defines the boundary between two different structures. This coating gives also some stiffness to these structures allowing the trainee to feel some resistance while introducing puncture needle or cutting device.
• the training system may comprise a pump connected to the artificial blood vessels causing flow of the liquid in the artificial blood vessels to simulate under sonography the flow of blood within the vessels.
• the artificial ligament should be securely fixed to the bone structure to avoid displacement during a surgical cutting operation, and needs to be visible under sonography by partially reflecting some ultrasounds and allowing some ultrasounds to pass through to be able to see the deeper structures such as nerves situated under the ligament.
• the severability of the material when cut by a surgical instrument should replicate that of real ligaments for accurate haptic feedback.
• Advantageous materials that may be used as ligaments include bands of cellulose and polyester that have semi-elastic properties. These structures may be coated with alginates to mimic ligament pathological thickening.
• the artificial ligaments may be securely attached to the artificial bones through holes 5 provided in the base wall 4a of the support with a knot of the artificial ligament on the opposite side.
• Various mechanical clamping mechanisms or adhesives may also be used to securely fix the ligaments to the bone structure.
• Artificial muscles may advantageously be formed from a material comprising a hydrophilic colloid such as agar agar (protein :0,4% carbohydrate: 0,1%, Fat:0,l%, Fibers: 86,4%) water 1,3% (l,3g/L of water)) .
• Gelatine e.g. containing 160 g/L of water
• an echogenic powder e.g. sugar free Metamucil (Brand Psylium hydrophilic mucocilloid fiber (e.g. containing 80g/L of water)
• Other possible materials for forming the artificial muscles include latex (e.g. Latex: 33% Water: 66%, Amoniac: 0,3%) and alginates (e.g. derived from brown algae macrocystis pyrifera and ascophyllum nodosum).
• Artificial subcutaneous/interstitial tissues should be formed of hypo-echoic materials. There is often no need to simulate the normal connective tissue septa like normal subcutaneous tissue.
• the material of the artificial subcutaneous/interstitial tissues may advantageously comprise or consist of a hydrophilic gel, for instance a hydrophilic colloid such as agar agar, a polysaccharide.
• Agar agar is an advantageous material choice, as it is hypo-echoic, it is relatively resistant to pressure, it offers limited resistance when a perforating instrument is introduced in it, and, after retrieval of the instrument, it reforms without an echogenic trace nor gas bubbles or plane of rupture, which would generate sonographic artefacts. Finally, it allows injection of a liquid with quick diffusing of the liquid, quite similar to what happens in real medical injections.
• Fat tissue layer may be represented by materials similar to those used for the interstitial tissues or for instance wheat semolina (e.g. containing protein : 13% carbohydrate: 66%, Fat:2,3%, Fibers: 7%) layer spread underneath the elastomeric skin sheath.
• wheat semolina e.g. containing protein : 13% carbohydrate: 66%, Fat:2,3%, Fibers: 7%
• the artificial subcutaneous/interstitial tissue material needs to be contained by an artificial skin which forms an envelope containing the artificial subcutaneous/interstitial tissue material.
• This artificial skin beside enveloping the hydrophilic gel, is helpful in the surgical simulation as it provides haptic feedback to the trainee, replicating the sensation of perforating or cutting the skin.
• the artificial skin may advantageously comprise or consist of an elastomer such as a film or sheath of latex or of a silicone elastomer.
• the present invention provides a mannequin replicating the region of anatomical interest (such as a hand, a limb, a trunk, a neck) and possessing physical and echogenic properties allowing teaching of ultrasound- guided medical acts.
• Models can also be developed for animals, to be used for example in veterinary medicine.
• different materials or composition of materials to simulate the different tissues that need to be represented are arranged together by various possible manufacturing techniques to correspond in shape and volume to the normal (or pathological) anatomy of the region of interest. Each material is selected to provide echogenicity properties mimicking as close as possible the tissue it represents.
• Some of these materials are configured to allow the introduction of a medical instrument, like a needle, a cutting device, a clamp or another tool, with the following characteristics, that can be modulated to each clinical situation simulated : (1) resistance to the introduction and displacement of the medical instrument, resembling the in vivo resistance to the instrument ; (2) no specific sonographic artefact, other than the artefact generated by the instrument itself ; (3) no trace of the passage of the instrument, upon retrieving the instrument ; (4) no breakage of the material related to the passage of the instrument, allowing for example the formation of bubbles or plane of cracks.
• Some of the selected materials are designed to be cut, simulating biological ligament structures that need to be released, with a resistance to the act of cutting, similar to the simulated ligament, and without dislodging the ligament from its anchorage to the rest of the model under the force of the manipulation.
• the mannequin is preferably also configured to be dissectible, so that the trainee can verify if the simulated operation has been completed.
• a mannequin according to embodiments of the invention may be ecologically friendly, by the use of recyclable or biodegradable materials for many materials, as well as being economical.
• the mannequin may represents only a portion of the anatomical region to be studied ; the other portions can be of simple shapes and materials, allowing for instance to conveniently dispose the mannequin in a stable way on a surface such as a table surface, during sonoguided simulated procedures.
• the support 4 comprises an open box 4b that contains a base wall insert 4a on which the artificial bone structure 8 is supported.
• the base wall comprises holes 5 allowing to fix the artificial ligaments 14.
• a cover or top wall 4c having a negative profile 7 of the outer surface of the body part corresponds to the surface of the simulated skin in negative, to serve for moulding the skin made with a layer of artificial skin material.
• the box and cover parts 4b, 4c and the bone structure 8 may advantageously be made by additive manufacturing or by injection moulding.
• the cover After fixing the artificial ligaments, assembling manually the tissues representing the nerves and blood vessels, and pouring heated liquid agar-agar, the cover may be closed over the open box. After cooling, the agar agar forms a gel, covered by the latex or silicone skin, containing the simulated nerves, vessels, muscles and bony structures.
• the cover 4c on the box 4b may be kept closed until the training exercise. If needed, it can be sealed and irradiated for sterilization to be conserved for a long period.
• Figure 1 illustrates a production step of a prototype hand mannequin where the artificial bones are set on a perforated support that allows passing of sutures or other fixation devices intended for attachment of artificial anatomical structures such as ligaments, tendons, and blood vessels.
• Figure 2 illustrates a production step of a cover for the manufacturing of the prototype hand mannequin, where the cover 4c is configured to be placed over the open box 4b forming the support to inject / mold an anechoic medium replicating the tissues surrounding the artificial bones, ligaments, tendons and blood vessels.
• the cover or base comprises an orifice vent 9 to let air bubbles escape during the molding process.
• Figure 3 illustrates a production step of a cover for the manufacturing of the prototype hand mannequin, where the cover 4c comprises on its inner side a negative imprint 7 of the hand outer profile to mould the artificial tissue formed around the artificial bones, ligaments, tendons and blood vessels, whereby a layer of artificial skin material may be coated or otherwise placed or formed on the negative imprint 7 to create the artificial skin layer.
• Figure 4 illustrates steps of the manufacturing of the prototype hand mannequin, showing 3D models representing the three main tissues that are found in the hand mannequin: (A) Artificial bones (B) Artificial anechoic medium, (C) Artificial skin, (D) The cover, (E) The cover closed over the support, showing with transparency of the cover the hand mannequin position therein.
• Figure 5 illustrates steps of the manufacturing of the prototype hand mannequin, showing:
• coloured gelatin tubes e.g. beef or pork gelatin but may be replaced by plant based food derived from flours of cereals, grains or beans for instance of wheat (protein : 10-13% carbohydrate: 60-70%, Fat: 1-2%, fibers: 2-3%) rice (protein :2-3%
• Figure 6 illustrates steps of the manufacturing of the prototype hand mannequin, showing the use of a soft material, in this example derived from wheat semolina, to mimic fat tissue underneath the skin, whereby figure 6a illustrates the artificial fat tissue placed of the inside of the artificial skin layer formed on the negative imprint and figure 6b shows the artificial bone structure with tendons and nerves assembled thereon.
• the artery arch is mimicked by a tube made of wheat semolina.
• the artificial ligaments configured to be cut during training are made from synthetic ribbon of cellulose and polyester selected to give a close to real haptic sensation during the cutting process while also giving a very similar sonographic view.
• Figure 7a illustrates the finished prototype hand mannequin, whereby after moulding of the anechoic middle, the latex or elastomer skin aspect may be modified by the additional deposition of artificial fat tissue, for instance in this example wheat semolina, alternatively silicone layer underneath the latex sheath can be used. This aspect may be confirmed when the trainee cuts open the artificial skin (figure 7b) to assess the completeness of the ligament release performed and the absence of other tissue damaged involuntarily.
• artificial fat tissue for instance in this example wheat semolina
• silicone layer underneath the latex sheath can be used.

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• 2022
  • 2022-09-28 EP EP22198466.9A patent/EP4345798A1/de not_active Withdrawn
• 2023
  • 2023-09-27 EP EP23773326.6A patent/EP4595042A2/de active Pending
  • 2023-09-27 WO PCT/EP2023/076690 patent/WO2024068726A2/en not_active Ceased

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