JP5939536B2 - Wet box and training apparatus for minimally invasive surgery using the same - Google Patents

Description

The present invention relates to a means and apparatus for performing fine work training and skill evaluation in minimally invasive (endoscopic) surgery.

Minimally invasive (endoscopic) surgery is rapidly becoming widespread in all clinical fields because it places less burden on patients, but it uses endoscopes with a narrow field of view and forceps with a low degree of freedom of operation. High technology is required. For this reason, in a laboratory level environment, training and skill evaluation using a dry box or a virtual simulator are performed. However, since these cannot use actual organs, they must use simulated organs made of silicon or the like, and this is not a wet environment close to actual surgery, so it is not realistic and practical. There was a problem that the effect was low in terms of training. In terms of training, the most effective method is training using large animals such as pigs and dogs, but special equipment is required, and in recent years it has also been implemented internationally from an ethical point of view. Has become very difficult. Similarly, regulations on small animals such as mice and rats are becoming more stringent.

On the other hand, because the circulatory system of chicken is very similar to that of humans, drug testing and culture research using eggs (including chicken embryos) have recently been conducted in the medical field ( For example, Patent Documents 1 and 2) have the advantage that the ethical threshold is relatively low. However, as far as the present inventor knows, no examples of applying chicken eggs to endoscopic surgery training or the like have been known.

Based on the background as described above, the present inventor used chicken eggs in order to perform training and skill evaluation of fine work in minimally invasive (endoscopic) surgery at low cost and in a laboratory environment. The present invention has been accomplished by earnest research on a desktop type, wet type training apparatus and a manufacturing method thereof.

JP 2005-278614 A JP-A-5-49364

As described above, since the conventional endoscopic surgery training apparatus performs evaluation in a dry environment, it is not sufficient in terms of skill evaluation in actual surgery. In addition, since it has become difficult to conduct experiments with large animals due to recent ethical restrictions, it is strongly desired to develop a system that can easily perform training in a wet environment. In order to solve this problem, the present inventor aimed to develop a device that uses a chicken egg that is easily available and has no ethical problems as a simulated organ.

In the present invention, a chicken egg (including a state of a chicken embryo until a fertilized egg becomes an individual) is formed into a wet box using an artificial transparent shell, and this is used as an imitation organ.

That is, the present invention is a wet box for training of minimally invasive surgery in which a chicken embryo is housed inside a regular polyhedral container, and the side or ridge portion (hereinafter referred to as a frame) of the regular polyhedral container. Is made of biocompatible metal, plastic, ceramics or glass, and the surface portion (the surface portion excluding the frame) is made of a biocompatible oxygen permeable membrane. It is a featured wet box.

The frame of the wet box must be formed of a material that has biocompatibility, does not deform even when an egg is placed, and has a high rigidity that does not cause breakage during handling. Plastics, ceramics or glass are suitable. The metal is preferably titanium or stainless steel, and the plastic is preferably a photocurable resin in terms of ease of processing. In addition, ceramics and glass can be used. If necessary, in order to ensure biocompatibility, a surface coating or a treatment for removing the toxicity of the material itself may be performed.

The surface portion needs to be formed of an oxygen permeable membrane having biocompatibility and a certain degree of durability, but has a durability (viscoelasticity) that cannot be broken when a surgical instrument is inserted. It is necessary to have. A fluorine-based resin as described later and a silicon-based material such as polydimethylsiloxane (PDMS) are preferable.

Another aspect of the present invention is a training apparatus for minimally invasive surgery, wherein the wet box is used as a simulated organ. In addition to the wet box (1 in FIG. 1), such a training apparatus is normally used as an endoscope, a microscope or a camera 2 attached to the training apparatus, forceps 3, and display 4 as illustrated in FIG. , Personal computer 5, other heating means, external fluid exchange device, electrical stimulation device or mechanical stimulation device (6 in FIG. 1), and the like.

The training device of the present invention has the greatest feature in that it can be observed from all directions and accessed with a surgical instrument by transferring eggs to a transparent artificial shell and culturing them. In addition, eggs can be preserved for a long time without requiring a special environment such as a culture solution by culturing eggs at a certain temperature while leaving yolk.

Conventionally, there has not been realized a device capable of quantitative evaluation of training skills using actual organisms in a laboratory environment while taking ethical rules into consideration. On the other hand, in the apparatus of the present invention, it is possible to insert a small-diameter forceps into a chicken egg and perform training using tissues, blood vessels, or the like formed inside the egg. Also, by measuring the tip position of the forceps with various sensors, it is possible to efficiently perform training, and in addition, quantitative evaluation of the skill can also be performed. By using chicken eggs in this way, it is possible not only to easily build a wet environment compared to small animals such as rats, but also to greatly reduce the size of the entire device in terms of availability and breeding. It becomes possible.

It is a schematic explanatory drawing of the training apparatus for minimally invasive surgery of this invention. It is explanatory drawing of an example of the wet box of this invention. It is a figure which shows the preparation processes of the wet box of this invention.

The wet box of the present invention is for training of minimally invasive surgery in which chicken eggs are housed inside a regular polyhedral container, and the side or ridge portion (frame) of the regular polyhedral container is It is made of biocompatible metal, plastic, ceramics or glass, and the surface portion (the surface portion excluding the frame) is made of a biocompatible oxygen permeable membrane. The inventor of the present invention pays attention to a chicken egg having a structure similar to that of a human circulatory system, and conceived that the wet box containing the egg is applied to a training apparatus for minimally invasive surgery.

The frame of the wet box must be formed of a material that has biocompatibility, does not deform even when an egg is placed, and has a high rigidity that does not cause breakage during handling. Plastics, ceramics or glass are suitable. The metal is preferably titanium or stainless steel, and the plastic is preferably a photocurable resin in terms of ease of processing. The photocurable resin is not particularly limited as long as it can be cured by light such as X-rays, ultraviolet rays, or visible light. For example, acrylic resin, epoxy resin, etc. can be mentioned. The toxicity of the material itself may be removed by heat treatment or the like.

The surface portion is formed of an oxygen permeable membrane having biocompatibility and a certain degree of durability. As the oxygen permeable membrane, known ones can be used, but among them, non-porous plastics that are superior in mechanical strength (shape retention) and oxygen permeability without the risk of contamination from bacteria are preferable. used. Moreover, it is necessary to have durability (viscoelasticity) that cannot be broken when a surgical instrument is inserted. Specifically, fluororesin such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, silicon such as polymer mainly composed of polydimethylsiloxane (PDMS) and tris (trimethylsiloxysilyl) styrene System materials are preferred.

The training apparatus or simulator for minimally invasive surgery of the present invention is as shown in FIG. In this simulator, as shown in FIG. 1, a container containing a chicken egg is used as a wet type container, a surgical instrument of several millimeters is inserted, and training using tissues or blood vessels formed inside the egg is performed. Can be done. Further, by measuring the tip position and force information of the forceps using a sensor or the like, training can be performed efficiently and quantitative evaluation of the skill can also be performed. By using chicken eggs in this way, not only can we easily build a wet environment compared to small animals such as rats in terms of availability and breeding, but also the size of the entire system can be greatly reduced. It becomes possible.

The advantages of the simulator according to the present invention are summarized as follows. (1) Since it is a wet type, training and technical evaluation with a high sense of reality (with sensation) can be performed using actual living organisms, even in a special environment. (2) Easy to handle. That is, it can be obtained at a low cost, and since the embryo grows using the yolk as a nutrient source, a special culture solution or the like is unnecessary, and the growth cost is low. In addition, it is easy to handle because of its fast life cycle. (3) In terms of ethics, ethical resistance is less than that of conventional large animals such as pigs and dogs, rats, etc., assuming that experiments are conducted at a stage prior to hatching. (4) The size can be reduced. That is, since eggs are used, training and the like can be performed in a desktop environment. (5) Since the outer shell is transparent, observation can be performed using a normal camera or microscope instead of using an expensive endoscope. (6) Further, in the future, it can be applied and expanded not only in the surgical field, but also in training and technical evaluation in various medical fields such as endoscopy and microsurgery.

The biggest problems when using eggs are the inability to observe the inside directly from the outside of the shell and the vulnerability of the shell. On the other hand, although the technology to transfer the egg contents to an artificial transparent shell (polymer, glass container, etc.) and hatch has been established, the material and rigidity of the shell itself is the insertion of the surgical tool. Because it was not developed for the purpose and operation, there was nothing transparent and capable of inserting a surgical instrument and having sufficient rigidity. The wet box of the present invention is obtained by replacing the contents of an egg with an artificial product having high biocompatibility, transparency and high rigidity. As shown in FIG. 2, the wet box of the present invention is one in which eggs are stored in a regular polyhedral container. By using such a box, it is easy not only to observe the internal state with an external camera and evaluate the blood vessels and organs in the egg, but also to change the posture of the box You will be able to access the location.

In the present invention, a regular polyhedral container used as a wet box container means a container having a regular tetrahedron, cube, regular octahedron, regular dodecahedron, or regular icosahedron. A cubic material is preferable because it is relatively easy to produce.

Conventionally, it is known that the oxygen permeability of a container is the most important for raising a chicken embryo or egg in an artificial container. Here, the oxygen transmission coefficient α of the material used for the wet box can be expressed as α = Vch / τSΔp (Equation 1) (Vc is the total amount of gas passing through the film of thickness h during the time τ) Is expressed as the volume of gas in the standard state, S is the effective transmission area, Δp
Is the difference in the concentration of gas passing through the membrane converted to a pressure difference). In the present invention, in order to satisfy the required specifications of the box, an oxygen permeable membrane that is easy to form and has high transparency and biocompatibility is used.

For example, the case where PDMS is used as the oxygen permeable membrane will be described below. As a material that satisfies such requirements, PDMS that is easily formed and has high transparency and biocompatibility is often used as a material for the box. The oxygen permeability of PDMS is α = 3.0 × 10 ⁻¹¹ cm ³ cm / cm ²
It is about spA and is known to have a high oxygen permeability. For example, considering that a cubic box with a side of l and a film thickness h as shown in FIG. 2 is produced using PDMS, a chicken egg takes in about 6 L of oxygen in about 21 days until hatching. Assuming that Vc = 286 mL of oxygen needs to be taken up per day, Δp = 101.33 kPa, τ = 86400 s. Moreover, since the volume of the egg is about 50 ml, considering that a box with one side having l = 40 mm is provided with a margin, the surface area S is 9600 mm ² . Therefore, from the above equation 1, the condition of the thickness h is calculated that h = ατSΔp / Vc is smaller than 0.88 mm. In FIG. 2, 7 indicates a frame, and 8 indicates a surface portion.

On the other hand, in order to increase the oxygen permeability, it is desirable to reduce the thickness as much as possible, but because the Young's modulus of PDMS itself is as low as 100 kPa order, the weight including the contents of the egg cannot be supported and the box shape cannot be maintained. . Therefore, in the present invention, as shown in 7 in FIG. 2, a structure using a photocurable resin having sufficient rigidity is disposed on the side or ridge portion constituting the frame of the container. For example, a hollow structure having a ridge (side or beam) thickness of 4 mm may be designed. Along with this, the surface area for permeating oxygen is reduced by about 40%, so that the actual thickness condition is finally such that the surface portion 8 (oxygen permeable membrane) satisfies the thickness h <0.55 mm. Need to be created.

As a container, it is important to use a container that is transparent and has a certain degree of rigidity and is constructed using a material having an oxygen permeability that allows eggs to grow, and that can freely change its posture in any direction. . It is also important to be able to insert a surgical instrument such as a chestnut and to observe the state with an endoscope or a microscope. Hereinafter, the present invention will be described in detail by way of examples.

Hereinafter, a wet box manufacturing method will be described. FIG. 3 shows an example of a box manufacturing process. First, a frame shape composed of a photocurable resin is produced using a three-dimensional stereolithography machine (a), and post-baking is performed to remove the toxicity of the resin. Next, a resin for forming an oxygen permeable film on the glass substrate, for example, PDMS is spin coated (b) to form a thin film having a thickness h, which is baked and cured. At this time, the film thickness can be controlled by adjusting the rotation speed and time of the spin coating. Next, a PDMS thin film is attached to the frame to form a box with an open top (c). Then, after filling with water and performing a simple leak test to confirm that there is no leak, sterilization is performed with UV light (d).

On the other hand, sexual eggs are cultured in a thermostat (temperature 39 ° C., humidity 99%) for 2 days, and then transferred to a box sterilized with UV light (e). It is possible to transfer the chicken embryo after it has grown to some extent, but as the growth progresses, blood vessels and other tissues adhere to the inside of the shell, so the transfer takes about 2 days to avoid damage during the transfer. It is preferable to perform the replacement. Finally, the upper part is closed to obtain the wet box of the present invention in a sealed state (f). Thereafter, the culture may be continued in a thermostatic chamber until use. In addition, it is more desirable to arrange oxygen in the lower part of the box so that oxygen is also taken in from the lower part.

[Evaluation of wet box]
In order to verify the possibility of long-term culturing in the produced box and the validity of the design method, experiments were conducted in which eggs were cultured with various changes in film thickness. For comparison, an experiment using a conventional plastic wrap was performed in the same manner. The evaluation was performed by counting the number of days in which the heart beat formed in the chicken embryo could be observed. As a result, when the film thickness of PDMS was large, it was confirmed that blood vessels and organs were not formed and embryos did not grow. On the other hand, when an appropriate thickness was set, the culture was successful for a maximum of 10 days. In addition, since the growth using the plastic wrap of the conventional method has progressed for about 10 days, it is considered that the culture can be performed for a longer period by adjusting the experimental conditions such as temperature and contamination management. (If it is about the 10th day, a thick blood vessel has grown to about 0.5 to 1.0 mm, so training or the like can be performed).

[Applied experiments using minimally invasive surgical instruments]
The experiment was performed using a box (thickness h = 0.4 mm) containing embryos cultured until the seventh day. In the experiment, the box was rotated to determine the insertion position of forceps (2 mm diameter) to access the heart. Thereafter, as shown in FIG. 1, the blood vessels and tissues around the heart were successfully manipulated with forceps while observing the organ with a microscope from above and magnifying the organ. During the operation, the operation could be performed without tearing the box membrane. Moreover, the hole opened by the surgical instrument can be closed again by applying PDMS or the like.

As described above, while observing the wet box of the present invention from the outside, it was confirmed that it was possible to access any part of the chicken embryo by freely rotating it. By measuring the tip trajectory and the like of the forceps, it is possible to implement a system for performing training and evaluation.

Since this simulator uses chicken eggs or embryos, it is suitable for training for minimally invasive surgery of the brain, eyeballs, and joints for treating microvessels and the like. On the other hand, when considering application to procedures involving relatively large organs, such as laparoscopic surgery, the operator treats large organs by using a robot (teleoperation) between the operator and the box. As described above, it is possible to use the haptic sense in an enlarged manner.

Considering that ethical regulations will become stricter globally in the future, it is clear that it will be difficult to conduct domestic animal experiments using large animals, and a sufficient training environment and quantitative evaluation should be established. Is an urgent need. In addition, surgery using endoscopes is performed not only in the surgical field, but also in internal medicine, orthopedics, urology, otolaryngology, and obstetrics and gynecology. Can be applied. In the future, by combining with robots, it can be applied to microsurgery devices and regenerative medicine research in the biotechnology field.

DESCRIPTION OF SYMBOLS 1 Wet box 2 Endoscope or microscope 3 Forceps 4 Display 5 Personal computer 6 Other vacuum means and heating means 7 Frame 8 Surface part

Claims (4)

A wet box for training of minimally invasive surgery in which a chicken embryo is housed inside a regular polyhedral container, and the side or ridge portion (hereinafter referred to as a frame) of the regular polyhedral container is biocompatible A wet box, characterized in that it is made of a metal, plastic, ceramics or glass having a property, and a surface portion (a portion of the surface excluding the frame) is formed of a biocompatible oxygen permeable membrane. The wet box according to claim 1, wherein the metal is titanium or stainless steel. The wet box according to claim 1, wherein the plastic is a photocurable resin. A training apparatus for minimally invasive surgery, wherein the wet box according to any one of claims 1 to 3 is used as a simulated organ.

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