WO2025137782A1 - Perfusion system for preparing a cadaver part for a surgical training model - Google Patents

Abstract

The present invention relates to a perfusion system for preparing a cadaver part for a surgical training model that comprises a case containing a circuit board, which is powered by a power source, having a pulse generator for generating a pulse at a certain frequency regulated in pulses per minute, an electric motor powered by the pulses generated by the circuit board and supported such that its shaft projects from said case. The system further comprises a switch for opening and closing the circuit that powers said electric motor, a first dual peristaltic pump head, a second dual peristaltic pump head, both second and first heads being attached to the projecting shaft of said electric motor, and a perfusion fluid container with perfusion fluid, having a first pumping circuit and a second draining circuit. The invention comprises a digital gauge suitable for detecting a pressure within a range of 40 to 70 mm Hg.

Description

PERFUSION SYSTEM FOR CONDITIONING CADAVERIC PIECE FOR SURGICAL TRAINING MODEL

DESCRIPTIVE MEMORY

TECHNICAL FIELD

The present invention relates to the education industry. In particular, it relates to training in surgical technique and a perfusion system for conditioning cadaveric specimens for surgical training models.

BACKGROUND

Flap surgery and microsurgery are complex and demanding disciplines in the field of medicine, requiring precise skills and practical experience. These techniques are used to reconstruct damaged or lost tissue, which can be essential for patient recovery after serious injuries or surgical interventions. The precision and skill acquired in these techniques are vital not only to the success of surgical procedures but also to the patient's postoperative quality of life.

Effective surgical training is of considerable social importance. Advanced flap and microsurgical techniques are fundamental in post-traumatic and post-surgical reconstruction, directly impacting patients' quality of life. The ability to perform these techniques accurately reduces the risk of complications, improves aesthetic and functional outcomes, and accelerates patient recovery.

Training in flap surgery and microsurgery has traditionally been conducted through courses using animal and cadaveric models. However, the quality of these courses depends largely on the fidelity of the cadaveric specimens used. The preservation and condition of these specimens are crucial for an accurate understanding of the anatomy studied and for the proper identification of key blood vessels. However, a limitation A significant drawback of traditional cadaveric models is the lack of realism in the representation of blood perfusion. Therefore, high-fidelity simulation models have been developed to replace cadaveric models in surgical training.

Prior art

Document CN103886798B describes a highly simulated interventional surgery trainer that includes a human simulator unit with an abdominal cavity, animal organs, auxiliary channels, a blood collection reservoir, and a pump unit. The animal organs are located in the abdominal cavity of the simulator unit and connected to the auxiliary channels, which in turn are linked to the blood collection reservoir to supply and recover perfusate. The pump unit, located between the reservoir and the auxiliary channels, provides the power for perfusate circulation. This trainer uses transparent silicone hoses that can be repeatedly punctured without leakage to simulate the major blood vessels of the human body, and a colored liquid pumped through the pump assembly to simulate blood, thereby constructing blood circulation. Actual animal organs, such as the liver, spleen, and kidneys, fit the blood vessels of the human simulator training system, such as the inferior vena cava, portal vein, hepatic artery, and bile duct.

Document CN103886798B, which focuses on a human simulation unit for internal organs, lacks a focus on upper limbs, limiting its usefulness in detailed surgical procedures in this area.

Document CN113793545A describes an operation simulation device and an operational training system. This device includes a first and a second functional platform, as well as an installation platform. The first functional platform consists of a housing assembly, a perfusion assembly, a control module, and a multifunctional connector. The housing has two layers, with the inner layer forming a cavity for storing fluids. The infusion set and control module, which are located between the two layers of the housing, communicate with this cavity. The multifunctional connector is located in the housing. The second functional platform, which is placed on top of the housing, has a third housing that mimics the shape of the human body, forming an operational cavity. The installation platform, removably arranged on the housing, serves to secure tissues and organs.

Similarly, CN113793545A, although it provides an operative training system, is not specialized in upper limb simulation, which reduces its effectiveness in specific training such as flap surgery.

Document CN114373347A describes a highly simulated, intelligent training system for whole-organ surgery. This system includes multiple modules: a simulation training module, a control module, a body fluid circulation module, an intelligent monitoring and adjustment system, a cooling system, a voice recognition and video recording system, a touch screen module, a lifting system, a data evaluation system, and a power supply module. All of these modules are electrically interconnected with the control module. The system provides a simulation training modality for endoscopic surgery and develops various thoracoscopic surgeries by implementing intelligent control components.

On the other hand, CN114373347A, which is geared toward whole-organ surgery and thoracoscopic surgery, does not address the particular training needs of upper limbs, focusing more on simulating internal procedures. Document CN208218830U describes an automatic perfusion device that includes two bottles, a syringe needle, connecting tubing, two peristaltic pumps, a controller, a display screen, and an input keypad. The fluid inlet ports of the peristaltic pumps are connected to the bottles via emulsion tubing, and their outlets are connected to the syringe needle via connecting tubing. The input keypad is used to configure system control, including adjusting the flow time and rate of two types of liquids, and is connected to the controller, which is also linked to the display screen. This configuration eliminates the need to manually change liquids and allows for real-time display of the fluid flow rate and remaining experimental period, as well as adjustments during the experiment. The device also features additional functions such as schematic memory, flow modification, liquid switching, and emulsion tubing cleaning.

Furthermore, CN208218830U, despite its focus on automated perfusion, does not specialize in upper limb simulation and conditioning for flap surgeries and similar procedures.

Document US20170076635A1 describes a training system for vascular procedures that includes a simulator designed to replicate a portion of a human limb, such as a leg. This simulator consists of one or more replicated bones, a plurality of arteries connected to these bones, including at least one obstruction, and a flesh-like substance formed over the bones and arteries, in the shape of the replicated human limb. In addition, a fluid pump is connected to at least one of the arteries and is configured to pump a fluid through the plurality of arteries.

Also, US20170076635A1 , designed to replicate a human limb with a focus on vascular procedures, does not provide a suitable system for conditioning cadaveric limbs for detailed and realistic training in specific upper limb techniques, such as microsurgery or hand reconstructive surgery. Prior art documents present solutions in the field of surgical simulation and training; however, they show significant limitations in their applicability to upper-limb training, such as flap surgery. Overall, these prior art solutions do not meet the specific need for training in upper-limb surgical techniques using properly conditioned cadaveric models.

Technical problem

Currently, a technical challenge in upper extremity flap surgery training is the difficulty in obtaining training models that are both realistic and affordable in terms of cost and conditions. On the one hand, the production of high-precision artificial models that faithfully simulate the anatomy and physiology of the upper extremities entails high costs and significant technical complexities. These models, although advanced, often fail to fully replicate the unique characteristics of real human tissues, which is crucial for effective training in flap techniques.

On the other hand, the use of cadaveric specimens, which could offer a more realistic and economically viable alternative, faces the challenge of variability in their quality and state of preservation. Many available cadaveric specimens are not in optimal condition for surgical training, especially for delicate procedures such as upper limb flap surgery. This is due to factors such as inadequate preservation, tissue dehydration, or post-mortem changes that affect tissue elasticity and physiological response. Therefore, these specimens require specific conditioning to restore, as far as possible, their natural properties and facilitate realistic training. Therefore, there is a need to develop a system or method that can effectively condition cadaveric specimens for training in upper limb flap operations. This system should be able to revitalize and maintain cadaveric specimens in a state that closely simulates surgical reality, thus providing a viable and economically accessible alternative to high-precision artificial models. Such a training model would be invaluable in improving the quality and realism of surgical training, allowing medical professionals and students to practice and hone their skills in an environment that accurately mimics the complexity of upper limb flap procedures.

Technical solution of the present invention

The object of the present invention is a perfusion system for conditioning cadaveric specimens for surgical training models, comprising a housing containing an electronic board with a pulse generator, an electric motor, and a switch for regulating the circuit. Said system also comprises two double peristaltic pump heads and a container with perfusion fluid that mimics the properties of blood in color and viscosity. A first drive circuit and a second drainage circuit, with flexible lumens and a digital manometer, facilitate controlled and realistic irrigation of cadaveric tissues in the upper limbs. The perfusion fluid is composed of a mixture of human albumin and artificial blood, which faithfully simulates blood properties. The pulse rate and pressure of the system are adjusted for optimal conditioning of the cadaveric specimen without causing damage, thus allowing for more realistic and effective training in flap and microsurgery techniques.

Advantages of the present invention

One of the main advantages of this invention is its ability to provide highly realistic surgical training, especially in the field of flap surgery and microsurgery. By accurately simulating the properties of blood and blood perfusion, the system improves significantly improves the quality of training, allowing surgeons to practice on cadaveric models that closely replicate real-life operating conditions. This fidelity is essential for developing precise surgical skills and for a detailed understanding of human anatomy, particularly with regard to the identification and management of small, critical blood vessels. Furthermore, the ability to maintain cadaveric tissues in optimal condition for extended periods without causing significant edema or damage allows for longer and more productive training sessions.

Another important advantage of this system is its contribution to the availability and economic viability of surgical training models. By using cadaveric specimens, which are more accessible and affordable compared to advanced artificial models, the system's implementation is facilitated in a wide range of educational institutions and training centers. This democratizes access to high-quality surgical training, enabling more medical professionals to acquire and hone critical skills in a practical and realistic learning environment. The inclusion of an innovative perfusion solution, which avoids significant staining of vessels and tissues, further ensures the integrity and realism of the cadaveric model, expanding its applicability and effectiveness in various surgical training scenarios.

BRIEF DESCRIPTION OF THE FIGURES

Described below are figures of preferred embodiments of the present invention. It should be appreciated that the figures are provided for illustrative purposes only and that the invention is not limited by these illustrations. The figures are not necessarily to scale, and some features may be exaggerated or minimized to show details of particular components. Well-known components, materials, or methods are not necessarily described in great detail to avoid obscuring the present disclosure. Any specific structural and functional details described herein should not be construed as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art how to variously employ the invention.

Figure 1 schematically illustrates a system according to the present invention in a first embodiment.

Figure 2 schematically illustrates a system according to the present invention in a second embodiment.

Figure 3 is a photograph showing the results of conditioning a cadaveric piece of upper limb with the system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the invention, reference is made to the accompanying figures, which are part of this detailed description. The illustrative embodiments described in this detailed description and shown in the figures are not intended to be limiting. Other embodiments may be used, and other changes may be made without departing from the spirit or scope of the present invention as defined in the appended claims.

Referring to Figure 1, the present invention consists of a perfusion system for conditioning a cadaveric piece for a surgical training model, comprising: a housing (10) such as, for example, a plastic box with, inside: an electronic board (30) powered by a power source, with a 12 V pulse generator at a frequency regulated between approximately 50 to 70 pulses per minute (0.83 to 1.17 Hz); an electric motor (20) powered by the pulses generated by the electronic board (30) and supported such that its axis protrudes from said housing (10); and a switch (31) for opening and closing the circuit that powers said electric motor (20) and arranged accessible outside said housing (10); a first double peristaltic pump head (21) with an outlet connector and an inlet connector; a second double peristaltic pump head (22) with an outlet connector and an inlet connector; both first and second heads (21, 22) connected to the protruding shaft of said electric motor (20); and a perfusion fluid container (40) with a perfusion fluid (41); a first drive circuit formed by a flexible duct or lumen (42a) submerged at one end in said perfusion fluid container (40) and connected at the other end to the inlet connection of said first double peristaltic pump head (21), a lumen (42b) connected at one end to said outlet connection of said first double peristaltic pump head (21) and at the other end to the inlet of a digital pressure gauge (45), and a lumen (42c) connected at one end to the outlet of a digital pressure gauge (45) and at the other end to a port (44a), for example, a catheter needle, to be connected to a radial artery of the cadaveric upper limb piece (50); a second drainage circuit formed by a lumen (43a) immersed at one end in said perfusion fluid container (40) and connected at the other end to the outlet port of said second double peristaltic pump head (22), a lumen (43b) connected at one end to said inlet port of said second double peristaltic pump head (22) and at the other end to a port (44b), for example a catheter needle, to be connected to an ulnar artery of the upper limb cadaveric piece (50); said digital manometer capable of detecting a pressure in a range of 40 to 70 mm Hg (about 5332.9 to 9332.5 Pa), with an accuracy of at least 1 mm Hg (133.322 Pa).

According to the present invention, said perfusion fluid (40) consists of a mixture formed approximately one-third of human albumin and two-thirds of artificial blood. Said mixture is similar to blood in color and viscosity, with a high osmolarity.

Preferably according to the present invention, the frequency controller of said electronic board (30) is set to 60 pulses per minute. (1 Hz) for a pressure of approximately 45 mm Hg (5999.5 Pa) on the digital manometer (45). This pressure allows the cadaveric piece to be adequately conditioned without causing edema and damage to the vascular circuit of the piece.

The system of the present invention then makes it possible to obtain, with this pressure range, in particular the preferred pressure of around 45 mm Hg (5999.5 Pa) and perfusion fluid, a cadaveric piece of upper limb that recovers a resemblance to an upper limb of a living being, with the real precision of an upper limb of a living being for surgical training.

Thus, the system of the present invention allows for successful irrigation of forearm and hand flaps for an average of 8 hours without significant edema. The perfusion mixture allows for accurate identification of the arterial network, including small vessels such as perforators.

According to the present invention, said power source is a 12 V alternating current transformer for connection to the urban current network and feeding said electronic board (30). Other power sources can also be used to feed said electronic board (30) such as batteries or rechargeable batteries.

As illustrated in Figure 2, the first drive circuit may also comprise a three-way valve (46), such that said lumen (42c) is connected at one end to the outlet of said digital manometer (45) and at the other end to an inlet of said three-way valve (44a), with another lumen (42e) connected at one end to another inlet of said three-way valve (44a) and at the other end interchangeable with lumen (42b) at the outlet connector of said first double peristaltic pump head (21), and a lumen (42d) connected at one end to the outlet of a digital manometer (45) and at the other end to a port (44a), for example a catheter needle, for connecting to a radial artery of the cadaveric upper limb piece (50).

According to the present invention, said lumens (42a, 42b, 42c, 42d, 42e, 43a, 43b) are 1 to 3 mm in internal diameter.

Application example The experimental results obtained from the perfused cadaveric model for training in upper extremity flap surgery proved to be significantly successful. A dual-head peristaltic pump was used to perfuse five upper extremity cadaveric specimens with a simulated blood solution. This solution, composed of human albumin and fake blood, allowed effective irrigation for an average of 8 hours without causing significant edema in the cadaveric specimens. Perforator vessels were visible in all flaps, achieving spontaneous bleeding from the flap when elevated and also in the event of perforator injury. These results highlight the effectiveness of the conditioning system in providing a realistic training environment, allowing surgeons to practice flap techniques under conditions that closely mimic a real operation.

Validation of the model's appearance and content by independent experts was equally positive. The experts evaluated the model through a validation survey, assigning high scores in all aspects assessed. Specifically, they highlighted the model's ability to enable accurate identification of key structures such as the main artery, perforating vessels, and nerves in a surgical setting similar to that of a real surgery. Furthermore, the experts emphasized that the model's perfusion facilitated the identification of technical errors compared to non-perfused cadaveric models, suggesting a substantial improvement in the quality of surgical training provided by this innovative model.

The following questions were asked of experts, each with a score of 1 to 5, with 1 representing "Disagree" and 5 representing "Strongly Agree." The survey results are tabulated in Table 1.

I.- Is the model a useful tool for training microsurgical suturing skills?

II.- Is the model a useful tool for training in dissection and elevation of hand and forearm flaps?

III.- Does the model come close to the experience of performing a flap in a real surgical scenario? IV.- Does the model allow for better recognition of technical execution errors compared to a non-irrigated model? - Was it possible to identify perforating vessels when elevating the flap?

VI.- Was bleeding from perforating vessels visible if they were injured?

VIL- Was it possible to assess the perfusion of the flap once it was elevated?

VIII.- Would you prefer the use of an irrigated flap model to a dry model for microsurgical flap training?: a) Yes b) No

Table 1. Results of the survey conducted among experts

In Figure 3, a homodigital flap of the ring finger can be seen in a fresh cadaveric piece stored at -25 °C conditioned with the system of the present invention, showing the adequate bleeding of the elevated flap for precise and realistic surgical training, resulting from the conditioning of the cadaveric piece of the upper limb, with the system of the present invention.

In Figures 1 and 2, the following references are indicated below:

10: casing 20: Double peristaltic pump electric motor

21: First double peristaltic pump head

22: Second double peristaltic pump head

30: electronic board;

31 : power switch in container;

40: Infusion fluid container

41: perfusion fluid

42a, 42b, 42c, 42d, 42e: first circuit lumens

43a, 43b: second circuit lumens

44a, 44b: ports or catheter needle

45: digital pressure gauge

46: three-way valve

50: cadaveric piece of upper limb.

The terminology used herein is intended to describe particular embodiments only and is not intended to be limiting of the disclosed subject matter. As used herein, the singular forms "a," "an," "an," and "an" are intended to include plural forms as well, unless the context clearly indicates otherwise. It is further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The structures, materials, acts and corresponding equivalents of all elements of means or steps plus functions in the claims below are intended to include any structure, material or act for performing the function in combination with other claimed elements. as specifically claimed. The description of the present disclosed subject matter has been presented for illustrative and descriptive purposes, but is not intended to be exhaustive or limited to the disclosed subject matter in the disclosed form. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the disclosed subject matter. The embodiment was chosen and described to best explain the principles of the disclosed subject matter and practical application, and to enable others skilled in the art to understand the disclosed subject matter for various embodiments with various modifications that are suitable for the particular use contemplated.

Claims

1.- A perfusion system for conditioning a cadaveric piece for a surgical training model, CHARACTERIZED in that it comprises: a housing (10) with, inside: an electronic board (30) powered by a power source, with a pulse generator at a frequency regulated between approximately 50 to 70 pulses per minute (0.83 to 1.17 Hz); an electric motor (20) powered by the pulses generated by the electronic board (30) and supported so that its axis protrudes from said housing (10); and a switch (31) for opening and closing the circuit that feeds said electric motor (20) and arranged accessible outside said housing (10); a first double peristaltic pump head (21) with an output connector and an input connector; a second double peristaltic pump head (22) with an output connector and an input connector; both first and second heads (21, 22) connected to the protruding shaft of said electric motor (20); and a perfusion fluid container (40) with a perfusion fluid (41); a first drive circuit formed by a flexible duct or lumen (42a) submerged at one end in said perfusion fluid container (40) and connected at the other end to the inlet connection of said first double peristaltic pump head (21), a lumen (42b) connected at one end to said outlet connection of said first double peristaltic pump head (21) and at the other end to the inlet of a digital manometer (45), and a lumen (42c) connected at one end to the outlet of a digital manometer (45) and at the other end to a port (44a) for connecting to a radial artery of the cadaveric upper limb piece (50); a second drainage circuit formed by a lumen (43a) submerged at one end in said perfusion fluid container (40) and connected at the other end to the outlet connection of said second pump head double peristaltic pump (22), a lumen (43b) connected at one end to said inlet connector of said second double peristaltic pump head (22) and at the other end to a port (44b) for connecting to an ulnar artery of the cadaveric upper limb piece (50); said digital manometer capable of detecting a pressure in a range of 40 to 70 mm Hg (about 5332.9 to 9332.5 Pa). 2.- A system according to claim 1, CHARACTERIZED in that said perfusion fluid (40) consists of a mixture formed by approximately one third of human albumin and two thirds of artificial blood. 3.- A system according to claim 1, CHARACTERIZED in that the frequency controller of said electronic board (30) is adjusted to 60 pulses per minute (1 Hz) for a pressure of around 45 mm Hg (5999.5 Pa) on the digital manometer (45). 4. A system according to claim 1, characterized in that said first drive circuit comprises a three-way valve (46), such that said lumen (42c) is connected at one end to the output of said digital manometer (45) and at the other end to an inlet of said three-way valve (44a), with another lumen (42e) connected at one end to another inlet of said three-way valve (44a) and at the other end can be exchanged with the lumen (42b) in the outlet connector of said first double peristaltic pump head (21), and a lumen (42d) connected at one end to the output of a digital manometer (45) and at the other end to a port (44a), for example, a catheter needle, to connect to a radial artery of the cadaveric piece of upper limb (50).