Head model

Abstract

To provide a skull model facilitating the understanding of an operation including a brain stem, a skull base, a posterior fossa, and a craniocervical spinal cord transition part since there is no suitable model corresponding to the examination of the operation including the brain stem, the skull base, the posterior fossa, and the craniocervical spinal cord transition part such as an approach to an important part, for example, an ExtremeLateralApproach and a TranscondylarApproach in the operation including the skull base part.SOLUTION: A head model for training or teaching craniotomy of disease in the skull, comprising at least a portion of the temporal bone, the posterior fossa, and the atlanto-occipital joint.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a head model, and more particularly to a head model that includes the base of the posterior fossa and is useful for studying or teaching skull base surgery in deep brain regions. [Background technology]

[0002] The craniocervical junction is a common site for neoplastic, vascular, traumatic, congenital, and degenerative lesions. Due to its complex anatomical structure, deep location, and the presence of vital neural structures, surgical treatment of lesions in this region is challenging and requires careful attention. Therefore, when performing these procedures, it is important to minimize trauma to the brain, nerves, and blood vessels and ensure sufficient surgical space. Posterolateral and inferior anterolateral skull base surgical approaches are particularly important for vertebral and vertebrobasilar bifurcation aneurysms, inferior clivus and anterior foramen magnum lesions, and jugular foramen tumors. Summary of the Invention [Problem to be solved by the invention]

[0003] Surgery involving the skull base requires extensive exposure of the posterior fossa and craniocervical junction, including the occipital condyles. While images, videos, and partial model teaching materials exist, these have limitations in providing information on the sense of direction, distance, and touch during actual surgical approaches. Therefore, there are no suitable models for examining surgeries involving the brainstem, skull base, posterior fossa, or craniocervical junction, such as approaches to critical areas like the extreme lateral approach or transcondylar approach, making it difficult to understand surgeries involving the brainstem, skull base, posterior fossa, and craniocervical junction. [Means for solving the problem]

[0004] In order to solve the above problems, the present disclosure provides the following inventions.

[0005] A first aspect of the present invention is a head mannequin for training or education in craniotomy for intracranial disease, the head mannequin including at least a portion of the temporal bone, the posterior fossa, and the atlanto-occipital joint.

[0006] Another aspect of the present invention is the head model described above, wherein the atlanto-occipital joint is made up of a C1 joint and an occipital joint fixed by a wire.

[0007] Yet another aspect of the present invention is the above-described human head model, which includes at least one of cranial nerves, cerebral blood vessels, additional bone structures, dura mater, and tentorial dura mater. [Effects of the Invention]

[0008] This invention provides a novel three-dimensional model of the posterior cranial fossa as a learning tool to improve knowledge of skull base anatomy and surgical approaches. This model was created using a 3D printer based on CT data and incorporates artificial cranial nerves, cerebral blood vessels, bony structures, dura mater, and cerebellotentorial dura mater. These anatomical elements are differentiated by various colors, and the atlanto-occipital joint can be moved, allowing drilling to open the hypoglossal canal under a wide surgical field. This model is extremely useful for practicing posterior skull base surgical approaches. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the inside of a head mannequin according to an embodiment of the present invention, as viewed from the left side. [Figure 2] FIG. 1 is a diagram showing the outside of an embodiment of a head mannequin according to the present invention, as viewed from the right side. [Figure 3] FIG. 1 is a front view showing the inside of an embodiment of a head mannequin according to the present invention. [Figure 4] FIG. 1 is a diagram showing the outside of an embodiment of a head mannequin according to the present invention as seen from behind. [Figure 5] FIG. 2 is a top view showing the inside of the head model of the present invention. [Figure 6]FIG. 2 is a diagram showing the internal structure of the head model of the present invention, viewed from below the C1 vertebral region. [Figure 7] FIG. 10 is a schematic view of the head model of the present invention, showing the bone drilling process from the lower outside. [Figure 8] 10 is a simulated view of a far lateral approach with vertebral artery (VA) transposition in the head model of the present invention. [Figure 9] 10 is a simulated view of a posterior trans-petrosal labyrinthine approach in a head model of the present invention. [Figure 10] 10 is a simulated view of a posterior petrous approach in a head model of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The skull data for manufacturing the head model of the present invention is obtained by scanning the subject's skull using medical image processing techniques such as magnetic resonance imaging (MRI) or X-ray computed tomography, which provides detailed data on the internal structure and external shape of the skull.

[0011] The resulting scan data is converted into 3D CAD data using specialized software. This software handles Digital Imaging and Communications in Medicine (DICOM) data and converts the acquired image data into Standard Triangle Language (STL) format, making it suitable for 3D printing.

[0012] Based on the 3D CAD data obtained in this way, a cranial model is manufactured using selective laser sintering (SLS). Specifically, one side of the temporal bone, part of the occipital bone, and the C1 vertebral arch can be manufactured from the entire cranial information using SLS.

[0013] The powder sintering material used to manufacture the head mannequin of the present invention is a material that can be sintered by irradiation with laser light. It consists of 30-90% by mass of synthetic resin powder and 10-70% by mass of inorganic filler, preferably 50-80% by mass of synthetic resin powder and 20-50% by mass of inorganic filler. If the synthetic resin powder is less than 30% by mass and the inorganic filler is more than 70% by mass, the resulting artificial bone model may be hard and brittle and may not have the machinability of natural bone. If the synthetic resin powder is more than 90% by mass and the inorganic filler is less than 10% by mass, the machinability of each segmented artificial bone model may be poor. By adjusting the blending ratio of the synthetic resin powder and the inorganic filler, the hardness or softness or brittleness of the resulting artificial bone model can be adjusted, allowing the production of artificial bone models suited to various purposes, from the hard bones of elderly people to the soft bones of children.

[0014] There are no particular limitations on the synthetic resin powder used in producing the head model of the present invention, and examples thereof include nylon, polycarbonate, polyester, polyacetal, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polybutylene, ABS resin, cellulose-based resin, acrylic resin, epoxy resin, fluororesin, etc. These may be used alone or in combination of two or more, but among these, nylon is preferably used, and nylon 11 is particularly preferably used.

[0015] In the manufacture of the head model of the present invention, it is preferable that the fine particles of the synthetic resin powder are spherical. By making the fine particles of the synthetic resin powder spherical, a thin layer of sintered powder material with a uniform thickness and low porosity can be formed with good reproducibility.

[0016] Furthermore, in the present invention, it is necessary to remove unsintered powder from the openings exposed on the divided surfaces of each of the obtained divided artificial bone models. However, if the fine particles of the synthetic resin powder are spherical, it becomes easier to remove the unsintered powder.

[0017] There are no particular restrictions on the size of the fine particles of the synthetic resin powder, but an average particle size of 5 to 200 μm is preferred, an average particle size of 20 to 120 μm is more preferred, and an average particle size of 40 to 90 μm is even more preferred. Synthetic resin powders with an average particle size of less than 5 μm are difficult to manufacture and may be expensive. If the average particle size of the synthetic resin powder exceeds 200 μm, the resulting artificial bone model may be less uniform, its machinability may be poor, and its removability from the opening may be reduced.

[0018] There are no particular limitations on the inorganic filler used in producing the head model of the present invention, and examples thereof include talc, calcium carbonate, glass beads, silica, clay, kaolin, barium sulfate, wollastonite, mica, titanium oxide, diatomaceous earth, hydroxyapatite, metal powder, etc. These may be used alone or in combination of two or more, but among these, glass beads are particularly preferred because they can provide an artificial bone model with good machinability.

[0019] The laser light used to manufacture the head model of the present invention is not particularly limited, and examples include CO2 lasers, YAG lasers, excimer lasers, He-Cd lasers, and semiconductor-pumped solid-state lasers. Among these, CO2 lasers are particularly suitable due to their simple operation and control. These lasers can be used alone or in combination. The type of laser used can adjust the manufacturing time, the degree of bonding of the powder sintered material, and the porosity of the resulting artificial bone model. In the method of the present invention, the atmosphere in which the laser light is irradiated onto the powder sintered material is not particularly limited, and can be, for example, hydrogen, helium, argon, nitrogen, or other gases, or air. Using an inert gas atmosphere prevents oxidation and corrosion of the powder sintered material and prevents deformation of the molded body due to overheating caused by laser light irradiation.

[0020] The C1 vertebral arch in the head model of the present invention is connected to the C1 condyle by wire fixation, allowing mobility of the articular surface of the occipital condyle.

[0021] In the skull model of the present invention manufactured as described above, cranial nerves such as the trigeminal nerve and oculomotor nerve can be positioned as needed. Furthermore, in the human skull model manufactured as described above, arteries such as the middle meningeal artery and internal carotid artery can also be positioned as needed. Furthermore, in the human skull model manufactured as described above, veins such as the superior ophthalmic vein and inferior ophthalmic vein can also be positioned as needed. Cranial nerves, arteries, and / or veins can be positioned in anatomically appropriate locations. For example, major cerebral arteries and cranial nerves can be made of synthetic resin (polyamide nylon) and painted with acrylic lacquer spray. Cranial nerves, including the trigeminal nerve, facial nerve, vestibular nerve, and lower cranial nerves, can be color-coded with different color gradients. Furthermore, semicircular canals, cochlear ducts, etc. can be individually colored for easy visual identification. In one embodiment of the skull model of the present invention, the cerebellotentorial dura mater can be used as a thin sheet, colored, for example, pink (yellowish pink).

[0022] The head model of the present invention first ensures a wide surgical field for manipulating the surface of the atlanto-occipital joint to open the hypoglossal canal (HC). This model more faithfully mimics actual surgical conditions by modeling the mobility required for complete exposure of the occipital condyle (CO). Furthermore, the vertebral artery (VA) can be movably incorporated to simulate the procedure for complete exposure of the occipital condyle (CO). These features are important for understanding bone drilling techniques and the significance of vertebral artery (VA) transposition in the extreme lateral approach. Furthermore, the tentorial dura (CT) is thinly colored, which helps surgical trainees better understand the tentorial incision technique in the transposterior petrous bone approach. Furthermore, the facial canal (CF), the vertical portion of the facial nerve running to the external auditory canal (EAM), the lateral semicircular canal (LSC), and the cochlear duct are each color-coded, allowing neurosurgical trainees to accurately understand the bone drilling techniques used in this surgical approach. Furthermore, the head model of the present invention is compact, lightweight, maintenance-free, and poses no biological or ethical risks. [Example]

[0023] An embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the following examples are intended to illustrate preferred examples, and the present invention is not limited to the examples shown below. Anatomical terms and names used in this specification are used for the purpose of convenient description and are not intended to be limited to specific body parts, structures, or functions. Naturally, anatomical terms are used in the description of the present invention, but they are merely used to describe parts of a model. Furthermore, these terms are intended to help those skilled in the art understand and implement the present invention, and are not intended to limit the scope of the claims.

[0024] The following example shows a skull model including the posterior fossa, showing a portion of the temporal bone, but the extent of the skull shown can be changed as appropriate depending on the intended surgical approach. Furthermore, the placement of tissues within the model can be changed or omitted as appropriate depending on the treatment or surgical approach for the target patient.

[0025] Figures 1 to 6 show the relative positions and extent of the skull model and the human skull in one embodiment of the present invention. The model in this embodiment was produced using a 3D printer based on the entire skull information reconstructed three-dimensionally using Mimics software (Materialise Japan, Yokohama, Kanagawa, Japan) from cranial data acquired using an Aquilion MDCT system (Toshiba Medical Systems, Otawara, Tochigi, Japan). The skull (2) and C1 vertebral arch (C1) (12) were fabricated layer by layer using a powder bed fusion method using synthetic resin (polyamide nylon) and inorganic filler (glass beads) powder. Furthermore, the major cerebral arteries and cranial nerves were made of synthetic resin (polyamide nylon) and painted with acrylic lacquer spray. The cranial nerves, including the trigeminal nerve, facial nerve, vestibular nerve, and lower cranial nerves, were color-coded, and the semicircular canals and cochlea were also colored for easy visual identification.

[0026] In this embodiment, the vertebral artery (VA) (6) is configured to pass through the transverse foramen (TF) (15a), and the C1 vertebral arch (C1) (12) is wire-fixed (27) to allow mobility of the articular surfaces of the C1 condyle (C1C) (10) and the occipital condyle. The dura mater (28) used to model the posterior cranial fossa was made of polyester fabric and attached to the other artificial dura mater and bone models using waterproof spray adhesive. The tentorial dura mater (CT) (25) is colored yellowish-pink to represent its actual color and is positioned three-dimensionally.

[0027] Next, an example of a surgical approach using a posterior fossa model according to one embodiment of the present invention will be described with reference to FIGS.

[0028] Figure 7 shows an overview of the posterior fossa model from a lateral inferior view. The vertebral artery (VA) passes through the transverse foramen (TF) (15a) (Figure 7A). The C1 vertebral arch (C1) (12) is configured with wire fixation to allow for movement of the articular surface between the C1 condyle (C1C) (10) and the occipital condyle (OC) (11) (Figure 7B). The dura mater (28) used to model the posterior fossa is a woven polyester fabric attached to another artificial dura mater and bone model using waterproof spray adhesive. The tentorial dura mater (CT) (25) is a thin sheet that may be colored separately from the dura mater (28) (Figure 7C). A craniotomy is performed using a temporal-inferior lateral posterior fossa approach depending on the lesion site, allowing for opening of the atlanto-occipital joint and bone removal in the superior occipital condyle fossa region (Figure 7D). The occipital condylar vein is identified in the occipital condylar fossa (CF) (13), and further bone resection is performed (Figure 7E, center). In this embodiment, the surface of the atlanto-occipital joint (26) is displaced to fully expose the occipital condylar fossa (CF) (13), providing a wide surgical field for opening the hypoglossal canal (HC) (4). The HC contains the hypoglossal nerve (XII) (14), the basal venous plexus (BA) (23), and a venous plexus connecting the marginal sinus (F).

[0029] Next, referring to Figure 8, we will describe a simulated view of the extreme lateral approach with vertebral artery (VA) (6) transposition. The jugular tubercle (JT) (5) is located above the opened hypoglossal canal (HC) (4). The vertebral artery (VA) (6) and the lateral vertebral masses of C1 and C2 may obstruct the view during epidural removal of the jugular tubercle (JT) (5). Therefore, the posterior wall of the transverse foramen (TF) (15a) is removed and opened (Figure 8A), and the vertebral artery (VA) (6) is moved inferiorly and medially from the atlanto-occipital joint (26) to expose the jugular tubercle (JT) (5) extradurally (Figure 8B). The lateral vertebral mass of C1 is drilled to ensure a wide surgical view, and the jugular tubercle (JT) (5) is drilled (Figure 8D). The dural penetration of the vertebral artery (VA) (6) is confirmed (Figure 8E).

[0030] Next, referring to Figure 9, we will describe a simulated view of the posterior petrosal translabyrinth approach. The mastoid process (MT) (9) and external auditory canal (EAM) (7) can serve as anatomical landmarks (Figure 9A). The transverse sinus (TS) (19), sigmoid sinus (SS) (8), superior petrosal sinus (SPS) (20), and temporal fossa roof (TT) (21) were exposed, and the dura mater of the roof was exposed (Figure 9B). Additionally, the digastric crest (DR) (16), posterior fossa dura mater (DP) (17), and jugular bulb were identified (Figure 9B). Medial and inferior to the lateral semicircular canal (LSC) (22), the facial canal (FC) (33), which covers the vertical portion of the facial nerve, is shown in yellow (Figure 9C). The semicircular canal (SC) (18) is shown in light blue (Figure 9D).

[0031] Next, referring to Figure 10, we will explain the approach to the dura mater, which is widely exposed after the bone drilling shown in Figure 9. As shown in Figure 10A, the exposed dura mater can be opened using the model of this embodiment. In this embodiment, the trigeminal nerve (V) (24) can be seen through the opening (Figure 10B). Furthermore, the facial nerve (VII) (30) and the vestibular nerve (31) can be seen within the dura mater (Figure 10C). The semicircular canals can then be drilled to reveal the internal auditory canal dura mater (IAM) (32) (Figure 10D). In a further embodiment, cutting the tentorial dura mater (CT) (25) allows for a wide surgical field from the frontal direction (Figure 10E). [Industrial Applicability]

[0032] Using the head model of the present invention to conduct surgical training for skull base approaches will help improve neurosurgical techniques. Furthermore, because the head model of the present invention is a handy bone drilling system, bone drilling training can be easily conducted as a private study. Furthermore, by modeling the intended brain tissue, surgical training can be conducted in a way that more closely mimics the surgical environment. [Explanation of symbols]

[0033] 1 Posterior fossa model 2. Skull 3 Siu Boi Kiu Kok (CPA): Cerebellopontine Angle 4. Hypoglossal Canal (HC) 5. Jugular Tubercle (JT) 6. Vertebral Artery (VA): 7. External Auditory Meatus (EAM) 8. S-shaped venous cavity (SS): Sigmoid Sinus 9 Mastoid Process (MT): Mastoid Process 10 C1 Condyles (C1C): C1 Condyle 11. Occipital Condyle (CO) 12 C1 Vertebral Arch: Atlas (C1) Vertebral Arch 13. Back of the head (CF) 14 Sublingual Nerve (XII): Hypoglossal Nerve 15a Transverse Foramen (TF) 15b Transverse Process (TP) 16. Digastric Ridge (DR) 17. Dura of the Posterior Fossa (DP) 18. Semicircular Canals (SC): 19. Transverse Sinus (TS) 20. Superior Petrosal Sinus (SPS) 21. Temporal Tectorium (TT): 22. Lateral Semicircular Canal (LSC) 23. Basilar venous plexus (BA): 24 Trigeminal Nerve (V) 25 Cerebellar tentorium dura (CT) 26 Atlanto-occipital joint 27 Wire fixing part 28 Dura mater 28a Middle cranial fossa dura 30 Facial nerve (VII) 31 Vestibular nerve 32 Internal auditory canal dura (IAM) 33 Facial Canal (FC): Fallopian Canal

Claims

1. A head model for training or education in craniotomy for intracranial diseases, A head model including at least a portion of the temporal bone, the posterior cranial fossa, and the atlanto-occipital joint.

2. 2. The head model according to claim 1, wherein the atlanto-occipital joint comprises a C1 joint and an occipital joint fixed by wires.

3. 3. The human head model according to claim 1, further comprising at least one of cranial nerves, cerebral blood vessels, additional bone structures, dura mater, and tentorial dura mater.

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