JP2010110360A - Method of manufacturing acetabular template of circumference of acetabular cup of hip replacement arthroplasty - Google Patents

Abstract

The conventional hip replacement is a highly invasive operation in which, in some cases, even a healthy bone other than the affected part is cut out in order to attach a standard implant to the human body, and for each individual patient. Therefore, it takes a long time to examine different optimal mounting positions and perform operations such as bone grinding, which is a burdensome operation for doctors and patients.
A step of obtaining three-dimensional image data of a bone shape of an individual hip joint portion by CT, MRI, MRA, etc., and using the three-dimensional image data, an acetabular template including an acetabular part is obtained. A step of creating shape data, a step of correcting the shape data of the acetabular template to modeling data for a three-dimensional layered molding machine, and a three-dimensional layered molding machine based on the modeling data of the acetabular template A method for producing an acetabular template around the acetabulum of artificial hip joint replacement, which comprises a step of molding a structure and a step of injecting a bioactive material into a gap between the structures of the acetabular template.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing an acetabular bone template in which an implant that can reduce the invasiveness of the acetabular bone and can be regenerated into a living bone is inserted into an affected part in hip replacement.

  Artificial hip replacement is an effective treatment that can provide pain relief and functional recovery early after surgery for hip joint disease. For the pelvic acetabulum, the acetabular bone is excavated into a hemisphere. A socket-type acetabular component is installed. For the femur, the femoral neck, which is a part of the femur, is cut off, the femoral head, which is also a part of the femur, is removed, and then the ball and Surgery to insert a femoral component consisting of a connecting rod-like stem.

  Hip replacement, which has been widely performed worldwide since the 1960s, has been performed in the treatment of hip joint disorders due to diseases such as osteoarthritis of the hip, femoral head necrosis, and rheumatoid arthritis. Ten cases have been implemented. Hip replacement is divided into a femoral side and a pelvic side, and the movable joint is made of a metallic material such as cobalt-chromium alloy or titanium alloy. The pelvic side is usually made of a metal shell. It has a structure with a polyethylene cup. There are two methods for fixing an artificial joint to bone: cement fixation using bone cement and cementless fixation without using bone cement.

  On the other hand, in recent years, a three-dimensional model is designed by a CAD system on a computer from image data obtained by MRI or CT scan, and this is sliced at a predetermined interval on a computer to create cross-sectional data. Based on the cross-sectional data, a model of the affected area of the patient is created by using a 3D additive manufacturing method in which a structural material such as a photocurable resin is laminated to form a 3D solid model. Surgery simulation can be performed, and attention has been paid also in the medical field (Patent Document 1, Patent Document 2, and Patent Document 3).

  Also, in published patent publication 2008-188400 (patent document 4), a part or all of the acetabulum or femur is applied to the acetabulum or femur using the three-dimensional shape of the acetabulum or femur which is the surgical site for hip replacement. A three-dimensional model consisting of a bone fitting part that can be fitted, and an installation information display part that provides information on the appropriate position or orientation of the acetabular component and femoral component based on the preoperative plan for hip replacement Based on this, we created an artificial hip joint replacement assisting member that was modeled by rapid product typing technology such as stereolithography, so that the operation position and orientation of the acetabular component or femoral component can be checked directly in the operative field so that surgery can be performed. What has been proposed.

  Furthermore, published patent publication 2002-65708 (Patent Document 5) describes an analysis method to assist in optimally designing the structure of a bone substitute embedded in an injured part in order to regenerate or repair a defective bone. It is shown that an element model for the above is created from image data obtained by MRI or CT scanning.

Furthermore, published patent publication 2007-229048 (Patent Document 6) discloses tricalcium phosphate as a bone prosthesis material that is excellent in bone affinity and osteoconductivity and has a good balance between bone formation rate and bioresorption rate. A bone replacement material is introduced.
Published Patent Publication 2006-78604 Published Patent Publication 2006-119435 Published patent publication 2006-314580 Published patent publication 2008-188400 Published patent publication 2002-65708 Published Patent Publication No. 2007-229048 Published Patent Publication No. 2004-26648 Published patent publication 2002-129203 Published patent publication 2008-86676 Published Patent Publication No. 8-38589 Yoshiaki Ishii, Takeo Matsuno, Toyonori Sakamaki: "Surgery for Hip Joints", Medical Shoinsha Kunio Takaoka: New generation of orthopedic surgery No. 6 “New artificial joint replacement and revision” MEDICAL VIEW Katsumoto Kunimoto, Yoshinori Saikawa: “Approach to product solutions using three-dimensional interpretation and stereolithography in the medical field” Master's thesis, Nagoya City University Graduate School of Art and Engineering, 2007, Reference, Japan Society for the Science of Design, 2008

The problems of conventional hip replacement are shown below. Both are major practical issues such as requiring re-operation depending on the situation.
1. Over time, the shape of the acetabular bone changes due to the bone connection of the titanium socket.
2. In order to attach a standard implant to the human body, it is a highly invasive operation, in some cases, to remove even healthy bones other than the affected area. In addition, examination of optimal mounting positions and bone grinding that differ for each patient Since it takes a long time to perform such operations, it is a burden on doctors and patients.
3. When a screw is used as a fixing method, there is a difficulty that position design is difficult, and when slack occurs, bone destruction is caused.
4). When bone cement is used as a fixing method, methyl methacrylate monomer, which is one of the bone cement raw materials, is released into the living body, resulting in a decrease in blood pressure.

  Note that the technique described in Patent Document 4 is intended to provide an auxiliary member for assisting replacement of an artificial hip joint, and does not solve the problems of conventional hip replacement or hip replacement. The technique described in Patent Document 5 relates to design support for a bone substitute analysis model, and does not solve the problems of conventional hip prosthesis or hip replacement.

  The present invention was made in order to solve the above-mentioned problems of conventional hip replacement, and a step of obtaining three-dimensional image data of the bone shape of a patient's individual hip joint by CT, MRI, MRA, etc. Using this 3D image data, the step of creating the shape data of the acetabular template including the acetabular part and the shape data of the acetabular template are corrected to the modeling data for the 3D stack molding machine A step of forming a structure of the acetabular template by a three-dimensional laminating machine based on the modeling data, and a step of injecting a bioactive material into the gap of the structure of the acetabular template A method for manufacturing an acetabular template around the acetabulum of an artificial hip joint replacement is provided.

  The present invention provides a step of obtaining three-dimensional image data of a bone shape of an individual hip joint portion by CT, MRI, MRA, and the like, and using this three-dimensional image data, an acetabular template including an acetabular part. A step of creating shape data, a step of correcting the shape data of the acetabular template to modeling data for a three-dimensional layered molding machine, and a three-dimensional layered molding machine based on the modeling data of the acetabular template A method for producing an acetabular template around an acetabular cap for artificial hip joint replacement, comprising: forming a structure; and injecting a bioactive material into a gap between the structures of the acetabular template. Therefore, since the template is molded including the bioactive material, the shape of the acetabular bone does not change over time, and the implant is attached to the human body. It is possible to perform artificial hip joint replacement with low human invasiveness, such as eliminating the need to remove even healthy bones other than the affected area, and eliminating the need for fixing methods such as bone cement and screws In addition, the artificial hip joint replacement, which has a heavy burden on doctors and patients, can be prepared before the operation, since the artificial hip joint where the optimal acetabular position according to the shape of the affected area of each patient, that is, the implantation position of the artificial femoral head has been determined, can be prepared. There is an effect that the surgical operation time can be greatly shortened.

  Further, the shape data of the acetabular template including the acetabular portion is obtained from the three-dimensional image data of the bone shape of the individual hip joint portion and the standard model hip joint data so that the acetabular position is optimal for the patient. Since it is created by analysis, an acetabular template having an optimal acetabular position for each patient can be easily created without imposing a burden on the patient.

  Further, since the three-dimensional laminating machine is an optical molding machine, and the structure of the acetabular template is formed of a photocurable resin, a structure having high accuracy, light weight and sufficient strength The body can be molded.

  In addition, since the structure of the acetabular template has a honeycomb structure composed of a wall surface with a plurality of holes, it is lightweight and has sufficient strength regardless of the type of 3D laminating machine or structure material. The structure which has can be shape | molded.

  In addition, since the in vivo active material is calcium phosphate or a filling material containing calcium phosphate as a main component, it has excellent affinity with living bones and bone regeneration, and sufficient strength and rapid bone regeneration can be expected.

  Furthermore, since the bioactive material is laid as an outer peripheral layer of the structure of the acetabular template, there is no harm to the human body, and initial bonding with a bioactive material is possible. .

Step 1: Create image data of the patient's hip joint using a diagnostic imaging system such as CT, MRI, MRA:
As a method of creating hip joint shape data of a patient using an image diagnostic system such as CT, MRI, MRA, and creating a bone model using a three-dimensional laminated molding machine such as an optical molding machine, for example, published patent publication 2006 -78604 (patent document 1), published patent publication 2008-188400 (patent document 2), published patent publication 2006-314580 (patent document 3), published patent publication 2008-188400 (patent document 4), etc. The indicated method and means can be used.

Step 2: Production of template data using 3D CAD / CAM:
In hip replacement, the position of the acetabulum is determined assuming the symmetry of the acetabulum. As the standard model hip joint data, for example, the outer shape of the template and the optimum position and direction of the acetabulum are determined according to the shape data of the hip joint on the opposite side to the affected part and the shape of the affected part removed by the operation. The allowable error is about 10 mm. The error is restored to its original location by the reproducibility of the human body.

Step 3: Write 3D CAD / CAM data to STL data to convert the created template shape data into 3D additive manufacturing data. Next, the STL data is corrected to data for 3D additive manufacturing with software for an additive manufacturing machine. The specific method is (Non-patent Document 3: Katsumi Kunimoto, Yoshinori Saikawa: “Approach to product solutions using three-dimensional interpretation and stereolithography in the medical field” Nagoya City University Graduate School of Arts and Sciences, Master's degree Papers, 2007, Reference, Japanese Society for the Science of Design, 2008) can be used. At this time, the structure of the acetabular template is designed from the template shape and the patient's hip joint data so that the position of the acetabulum is appropriate when the template is attached to the affected part. It is set as the structure which has the clearance gap which can inject | pour the filler which consists of acid tri-Ca.

Step 4: Production of template using 3D additive manufacturing method:
In this method and means, for example, as shown in Patent Documents 1, 2, 3, 8 or Non-Patent Document 3, a three-dimensional model is designed by a CAD system on a computer from image data obtained by MRI or CT scan. Then, this is sliced at regular intervals on a computer to create cross-sectional data, and based on this cross-sectional data, a three-dimensional stack model is formed by laminating structural materials such as photo-curing resin. A modeling technique can be used.

Step 5: Tri-Ca phosphate is made into a fine chip (2-5 mm in diameter) like a bone chip (BoneChip) and injected manually into a structure created by three-dimensional additive manufacturing, leaving no gap in the structure. Fill. In addition, tricalcium phosphate is laid on the outer periphery to promote fusion with bone through bioactivity. In the initial state, temporary fixing means that is harmless to the body used in existing surgery, such as a soluble adhesive, is used.

  Below, design and manufacture of acetabular template composed of artificial hip joint, plastic structure and Ca phosphate optimized for human body using rapid product methodology and bioactive material tricalcium phosphate A specific example will be described with reference to the drawings.

1) Creation of acetabular template shape data Data acquisition: DICOM data of a patient is acquired using an image diagnostic system such as MRI or CT.
2. Conversion to modifiable data: Convert to CAD data using DICOM data editing software (eg "OSIRIX").
3. Production of acetabular template (1) data on 3D software: Production of acetabular data using 3D software (eg “3DSMAX”, “RHINO” etc.) used in design modeling etc. I do. In addition, it is possible to use 3D software that can modify 3ds files. At this time, the structure (6) of the acetabular template (1) is formed so that the position and direction of the acetabulum (2) are appropriate when the template is mounted on the affected part. Designed from the mortar (5) data and having a structure (a honeycomb structure comprising a wall having a hole (12) having a gap into which the filler (7) made of tricalcium phosphate can be injected into the structure: FIG. 3). In designing the external shape of the template, the shape is designed in consideration of the shape of the affected part where bone destruction has occurred due to illness or the like, with the aim of creating a shape close to the patient's original acetabulum (5).
4). The generated acetabular data is converted into three-dimensional laminated data to be produced by a three-dimensional laminated molding machine. In this embodiment, a three-dimensional model is designed from image data by a CAD system on a computer, and this is sliced at a predetermined interval on the computer to create cross-sectional data.

2) Production of acetabular template A structure of an acetabular template made with 1.3D software is produced using stereolithography, which is a three-dimensional additive manufacturing machine. Specifically, as shown in Patent Documents 1, 2, 3, 8 or Non-Patent Document 3, for example, a three-dimensional solid model is formed by stacking structural materials such as a photocurable resin from slice data.
2. At this time, the structure (6) of the acetabular template is obtained from the template outer shape and the patient's acetabulum (5) data so that the position of the acetabulum is appropriate when the template is attached to the affected part. It is designed and has a structure having a gap into which a filler (7) made of tricalcium phosphate can be injected into the structure (a honeycomb structure made up of wall surfaces having holes (12): Fig. 3).
3. Post-processing: An acetabular template molded by stereolithography cannot be used as it is. Thereafter, in order to eliminate the harmfulness to the human body and to maintain the strength and durability of the shaped product, the following four steps are performed.
First stage: put into an ultrasonic cleaner containing a resin solution (MTFG: methylpropylene trinopricol) to remove the photo-curing resin still attached to the outside of the shaped product.
Second stage: Remove the ultrasonic cleaning liquid adhering to the first stage using isopropyl alcohol (IPA).
Third stage: Put into an infrared curing machine for about 20 minutes, and perform a process to bring out the durability of the shaped product that is a soft surface. Fourth stage: A polishing process is performed to smooth the surface using an abrasive.

3) Injection of tricalcium phosphate into the structure (6) (honeycomb structure) of the produced acetabular bone template.
1. In order to promote integral bone regeneration, the hole (12) is filled without any gaps so that the tricalcium phosphate can be dispersed. Further, in order to strengthen the adhesion between the structure and the acetabulum (5), triCa phosphate is laid on the outer periphery of the template to promote fusion with the bone through bioactivity. In the initial state, temporary fixing means that is harmless to the body used in existing surgery, such as a soluble adhesive, is used. As the tricalcium phosphate (TCP) powder, for example, a powder manufactured using a method (Patent Document 7) described in Japanese Patent Application Publication No. 2004-26648 can be used.
2. As a three-dimensional additive manufacturing machine, as disclosed in Japanese Patent Application Publication No. 2004-66360 (Patent Document 9), a liquid containing a substance that induces precipitation of a solid phase is ejected using an inkjet, Disposing a substance that induces precipitation at a desired position on the substrate; contacting the substance that induces precipitation of the solid phase with a deposition fluid to precipitate the solid phase on the substrate; By using the structure or pattern formation method, the structure itself can be made of tricalcium phosphate, and regeneration closer to a living bone can be promoted.

4) Mounting of a femoral implant using the template of the present invention.
1. The honeycomb structure of the acetabular template (1) having a wall surface in which a plurality of holes (12) are opened is connected with tricalcium phosphate filled in each honeycomb structure by opening the holes, The end result is a continuous bone mass in the acetabular template (1). The holes are sized to protect the strength of the structure, but the number varies depending on the patient's physical condition. Regarding the bone regeneration after treatment, it is disclosed in Japanese Patent Application Publication No. 2008-86676 (Patent Document 9) and Japanese Patent Application Publication No. 8-38589 (Patent Document 10).
2. The mounting of the acetabular template (1) can be completed before the insertion into the human body, so during the operation, the purpose of the temporary fixation for medical purposes around the affected area Applying adhesive and inserting an acetabular bone template into the affected area can significantly reduce the operation time.
3. On the side of the femur (3), a conventional artificial hip joint (4) (an artificial hip joint socket part (8), an artificial hip joint acetabular shell (9), an artificial hip joint head (10), an artificial hip joint) The acetabular template (1) is designed so that the position and orientation of the acetabulum (2) is optimal when the artificial hip joint (4) is installed. Since it is set, as a general rule, it is possible to minimize the time for adjusting the mounting position and examining the fixing method during the operation even when mounting on the femur (3) side.

  The present invention is suitable for use in manufacturing an acetabular template around a acetabulum of a medical device, in particular, hip replacement.

The figure which shows a state when setting an acetabular template in an acetabulum Exploded view for explaining the structure of the artificial joint 2 is an enlarged cross-sectional view of the portion indicated by “A” in FIG.

Explanation of symbols

1, acetabular template 2, acetabulum 3, femur 4, artificial hip joint 5, acetabulum 6, acetabular template structure 7, Ca phosphate injected into acetabular template
8. Artificial hip joint socket part 9, Artificial hip joint acetabular shell 10, Artificial hip joint head 11, Artificial hip joint stem 12, Hole in honeycomb structure wall

Claims (6)

  Using CT, MRI, MRA, etc., to obtain 3D image data of the bone shape of each patient's hip joint, and using this 3D image data, create shape data for the acetabular template including the acetabulum A step of correcting the shape data of the acetabular template to modeling data for a three-dimensional laminate molding machine, and forming a structure of the acetabular template by the three-dimensional laminate molding machine based on the modeling data. And a method for producing an acetabular template around the acetabulum of a hip replacement, which comprises a step of injecting a bioactive material into a gap between the structures of the acetabular template.   The shape data of the acetabular template including the acetabular part is analyzed from the 3D image data of the bone shape of each patient's hip joint part and the standard model hip joint data so that the acetabular position is optimal for the patient. The manufacturing method of the acetabular template around the acetabulum of the artificial hip joint replacement surgery of Claim 1 produced.   The acetabular circumference of an artificial hip joint replacement according to claim 1 or 2, wherein the three-dimensional laminating machine is an optical molding machine, and the structure of the acetabular template is formed of a photocurable resin. Acetabular template manufacturing method.   3. The manufacture of the acetabular template around the acetabulum of artificial hip joint replacement according to claim 1, wherein the structure of the acetabular template is a honeycomb structure constituted by a wall surface having a plurality of holes. Method.   The method for producing an acetabular template around the acetabulum of hip replacement according to claim 1 or 4, wherein the bioactive material is calcium phosphate or a filling material mainly composed of calcium phosphate.   The acetabular template around the acetabulum of hip replacement according to claim 1, wherein the bioactive material is laid as an outer peripheral layer of the structure of the acetabular template. Manufacturing method.

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