CN106388978A - Preparation method of acetabulum side model and guide plate based on three-dimensional reconstruction technology - Google Patents

Abstract

A preparation method of acetabular side model and guide plate based on 3D reconstruction technology, step 1, after processing the 3D CT data of the hip joint of the patient before operation, establish a digital 3D data model, reconstruct the 3D bony structure of the acetabular side, and restore the disease Original state; step 2, by analyzing the acetabular position, assessing the acetabular state, determining the bone volume around the acetabulum, and calculating the bone thickness around the acetabular area, formulate a plan for acetabular reaming and acetabular screw placement, and use these templates and models Carry out 3D modeling; step 3, use a 3D printer to make the preoperative acetabular side bone model, the intraoperative acetabular guide plate, the intraoperative acetabular screw guide plate, and the postoperative acetabular side bone model; step 4, integrate the above guide plate and model And check, if it is unqualified, it will be redesigned, if it is qualified, the guide plate and model will be sterilized and put into operation.

Description

A preparation method of acetabular side model and guide plate based on three-dimensional reconstruction technology

technical field

The invention belongs to the technical field of three-dimensional reconstruction of bones, and relates to a method for preparing an acetabular side model and a guide plate based on three-dimensional reconstruction technology.

Background technique

Three-dimensional reconstruction refers to the establishment of mathematical models suitable for computer representation and processing of three-dimensional objects.

Artificial joint replacement refers to the use of metal, high molecular polyethylene, ceramics and other materials to make artificial joint prostheses according to the shape, structure and function of human joints, and implant them into the human body through surgical techniques to replace the function of diseased joints to achieve relief. Joint pain, the purpose of restoring joint function.

3D printing is usually achieved using digital technology material printers. It is often used to make models in the fields of mold manufacturing and industrial design, and is gradually used in the direct manufacture of some products. There are already parts printed using this technology. The technology has applications in jewelry, footwear, industrial design, architecture, engineering and construction (AEC), automotive, aerospace, dental and medical industries, education, geographic information systems, civil engineering, firearms, and others.

At present, the incidence of diseases of the hip joint is very high, and artificial hip replacement is still the best treatment method at present.

However, this is currently the case for many patients, especially those with complex, severe hip deformities such as DDH; or for many less experienced arthrologists. During the operation, many troubles and difficulties are often encountered: such as the determination of the true acetabulum, the determination of the depth, position and direction of the acetabular screw, etc., which bring difficulties to the operation and often lead to poor prognosis of the patient. Specific problems such as: the operation time is long, if it is necessary to find the real socket, determine the position, depth, angle of the acetabular, and determine the position of the acetabular screw is too cumbersome. Surgical injuries are large, requiring repeated grinding of sockets, osteotomies, etc., resulting in complications such as heavy bleeding. Doctors are often unable to formulate precise and individualized surgical plans.

The success rate of complex artificial hip replacement (such as DDH) is not ideal, and the failure rate of difficult artificial hip replacement is relatively high, and the treatment effect is uncertain. has become an urgent problem to be solved.

There are several key points to solve the above problems: 1. To understand the real state of the disease objectively, comprehensively and correctly; 2. To formulate a personalized and precise surgical plan with definite curative effect, safety and reasonableness for surgical patients (especially those with difficult surgery); 3. Ensure the smooth implementation of the program without compromise.

Even so, the above method still needs to be realized after repeated analysis and demonstration by experienced experts, and the efficiency and success rate are worrying.

Therefore, how to use 3D printing technology to better serve hip surgery is particularly necessary.

Contents of the invention

The purpose of the present invention is to provide a method for preparing acetabular side model and guide plate based on three-dimensional reconstruction technology. It solves the problems that many doctors currently have, especially for patients with complex and serious hip joint deformities, such as DDH in determining the true socket and acetabular screws during surgery.

To achieve the above object, the technical solution of the present invention is:

A method for preparing an acetabular side model and guide plate based on three-dimensional reconstruction technology, comprising the following steps:

Step 1. After processing the preoperative 3D CT data of the hip joint, a digital 3D data model is established to reconstruct the 3D bony structure of the acetabular side and restore the original state of the disease.

Among them, the specific operation of establishing a digital 3D data model after processing the 3D CT data of the hip joint is: image import→threshold division (specific tissue extraction)→3D reconstruction model generation→computer-aided design (measurement, design guide plate, titanium plate veneer) , personalized implants, etc.) → 3D printing;

details as follows:

1) Image import:

Using 3D reconstruction software such as mimics and E-3D, it supports DICOM standard thin-slice scanning images. After the patient has passed the CT or MRI examination, the image in this format can be exported;

2) Threshold division:

The gray value of the CT scan image reflects the different attenuation coefficients of the tissue for X-rays; the threshold segmentation method is a calculation operation based on the gray image, and the tissues within the set threshold range are retained, while others are removed;

3) 3D reconstruction model generation:

In MIMICS and E-3D software, the object is described by the volume data of the three-dimensional primitive. After obtaining the volume data of the patient through CT and other tomography equipment, the three-dimensional mask of the object is obtained through threshold segmentation. Based on the three-dimensional mask The process of calculating the 3D model of the board is 3D reconstruction;

4) Computer aided design:

According to the actual situation of the patient's three-dimensional model, virtual surgery design is carried out; through CAD, 3-matic, MAGICS and other auxiliary tools or software, suitable guide plates or implants are designed to participate in the operation process and assist doctors in the operation;

5) 3D printing:

3D printing technology is also called incremental manufacturing, which refers to the direct drive of digital models, using metal, plastic, ceramics, resin, wax, paper, sand and other bondable materials to construct by layer-by-layer in rapid prototyping equipment Physical entity technology; put the 3D reconstructed patient model and the designed guide plate model into the rapid prototyping equipment, and finally get a 1:1 entity;

Step 2. By analyzing the position of the acetabulum, assessing the state of the acetabulum, determining the amount of bone around the acetabulum, and calculating the thickness of the bone around the acetabulum, formulate a plan for acetabular reaming and acetabular screw placement, and perform three-dimensional modeling of these guide plates and models. mold;

Among them, bone mass measurement:

Part of the spongy bone was not extracted during the threshold segmentation of the 3D reconstructed digital model, so the final 3D model will have many cavities; the model is repaired by 3D software, and after filling the holes, you can choose the place to be measured for measurement The volume of the 3D model to derive the bone mass;

bone thickness measurement

Through 3D software such as MAGICS, directly select two points on the front and rear walls of the model, and the distance between the two points is the bone thickness;

Step 3. Use a 3D printer to make a preoperative acetabular bone model, an intraoperative grinding guide, an intraoperative acetabular screw guide, and a postoperative acetabular bone model;

Among them, the material for making the model is medical polymer material, specifically nylon material FS3200PA

Step 4. The above-mentioned guide plate and model are integrated and inspected. If it is unqualified, it will be redesigned. If it is qualified, the guide plate and model will be sterilized and put into operation;

Among them, the specific inspection standard is: all guide plates and models will be subject to "testing whether the product matches the design drawing" as soon as they are 3D printed. Manual judgment is used. If the shape, structure, texture and other properties of the product are unqualified, If it is seriously unqualified, it will adjust the design parameters and re-make the product;

The "preoperative acetabular side bone model, intraoperative grinding guide plate, intraoperative acetabular screw guide plate and postoperative acetabular side bone model" were performed in sequence to perform surgical simulation tests to observe whether the relationship between each guide plate and each model can be correct and smooth. If there is any unsatisfactory situation, reprocess or remake.

Compared with the prior art, the beneficial effects of the present invention are:

1. By observing the model before surgery, the original state of the disease can be restored to the greatest extent

2. By observing the model and the guide plate before the operation, they can be combined and practiced to design a personalized and precise surgical plan for the patient

3. The position of the acetabulum, the size, depth and angle of the file can be quickly determined during the operation

4. The position, angle and length of the acetabular screw can be quickly determined during the operation

5. Realize accurate surgical plan, reduce surgical injury, shorten operation time, improve the success rate of complex artificial hip replacement, and reduce the failure rate of difficult artificial hip replacement.

Description of drawings

Fig. 1 is a schematic block diagram of the process of the method of the present invention.

Fig. 2 is a model diagram of the combination of the acetabular guide plate, the acetabular screw guide plate and the postoperative (after the acetabular) bone model in the test example of the present invention.

detailed description

The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments:

As shown in Figure 1, a preparation method of acetabular side model and guide plate based on three-dimensional reconstruction technology includes the following steps:

Step 1. After processing the preoperative 3D CT data of the hip joint, a digital 3D data model is established to reconstruct the 3D bony structure of the acetabular side and restore the original state of the disease.

Among them, the specific operation of establishing a digital 3D data model after processing the 3D CT data of the hip joint is: image import→threshold division (specific tissue extraction)→3D reconstruction model generation→computer-aided design (measurement, design guide plate, titanium plate veneer) , personalized implants, etc.) → 3D printing;

details as follows:

6) Image import:

Using 3D reconstruction software such as mimics and E-3D, it supports DICOM standard thin-slice scanning images. After the patient has passed the CT or MRI examination, the image in this format can be exported;

7) Threshold division:

The gray value of the CT scan image reflects the different attenuation coefficients of the tissue for X-rays; the threshold segmentation method is a calculation operation based on the gray image, and the tissues within the set threshold range are retained, while others are removed;

8) 3D reconstruction model generation:

In MIMICS and E-3D software, the object is described by the volume data of the three-dimensional primitive. After obtaining the volume data of the patient through CT and other tomography equipment, the three-dimensional mask of the object is obtained through threshold segmentation. Based on the three-dimensional mask The process of calculating the 3D model of the board is 3D reconstruction;

9) Computer aided design:

According to the actual situation of the patient's three-dimensional model, virtual surgery design is carried out; through CAD, 3-matic, MAGICS and other auxiliary tools or software, suitable guide plates or implants are designed to participate in the operation process and assist doctors in the operation;

10) 3D printing:

3D printing technology is also called incremental manufacturing, which refers to the direct drive of digital models, using metal, plastic, ceramics, resin, wax, paper, sand and other bondable materials to construct by layer-by-layer in rapid prototyping equipment Physical entity technology; put the 3D reconstructed patient model and the designed guide plate model into the rapid prototyping equipment, and finally get a 1:1 entity;

Step 2. By analyzing the position of the acetabulum, assessing the state of the acetabulum, determining the amount of bone around the acetabulum, and calculating the thickness of the bone around the acetabulum, formulate a plan for acetabular reaming and acetabular screw placement, and perform three-dimensional modeling of these guide plates and models. mold;

Among them, bone mass measurement:

Part of the spongy bone was not extracted during the threshold segmentation of the 3D reconstructed digital model, so the final 3D model will have many cavities; the model is repaired by 3D software, and after filling the holes, you can choose the place to be measured for measurement The volume of the 3D model to derive the bone mass;

bone thickness measurement

Through 3D software such as MAGICS, directly select two points on the front and rear walls of the model, and the distance between the two points is the bone thickness;

Step 3. Use a 3D printer to make a preoperative acetabular bone model, an intraoperative grinding guide, an intraoperative acetabular screw guide, and a postoperative acetabular bone model;

Among them, the material for making the model is medical polymer material, specifically nylon material FS3200PA

Step 4. The above-mentioned guide plate and model are integrated and inspected. If it is unqualified, it will be redesigned. If it is qualified, the guide plate and model will be sterilized and put into operation;

Among them, the specific inspection standard is: all guide plates and models will be subject to "testing whether the product matches the design drawing" as soon as they are 3D printed. Manual judgment is used. If the shape, structure, texture and other properties of the product are unqualified, If it is seriously unqualified, it will adjust the design parameters and re-make the product;

The "preoperative acetabular side bone model, intraoperative grinding guide plate, intraoperative acetabular screw guide plate and postoperative acetabular side bone model" were performed in sequence to perform surgical simulation tests to observe whether the relationship between each guide plate and each model can be correct and smooth. If there is any unsatisfactory situation, reprocess or remake.

The material is nylon material FS3200PA

Tensile Strength:

48Mpa, fully meet the strength requirements of drilling fixed guide plate, auxiliary grinding, cutting, drilling and other operations.

Melting point:

170. There will be no deformation and other problems through low-temperature disinfection and ethylene oxide and other disinfection methods. Physical properties:

Chemical properties:

The scientific name is polylaurolactam. A thermoplastic resin. Density 1.01 ~ 1.04. The melting point is 178-180°C. Water absorption 1.26% (in water at 20°C). Resistant to dilute acid, not resistant to concentrated acid. Alkali resistance is very good. Good solvent resistance.

Toxicological data:

1. Acute toxicity: mouse peritoneal cavity LD50: 100mg/kg;

2. Other multi-dose toxicity: oral TDLo in rats: 2730mg/kg/13W-C;

3. Reproductive toxicity: oral TDLo of male rats 42 days before mating: 1260mg/kgSEX/DURATION;

Examples of clinical trials:

step one

The three-dimensional direction of the pelvis is determined by the intersection line of the orientation block and the pelvis.

Step 2: Determine the size and position of the implanted acetabular cup through MIMICS software, and obtain the position of the center of the virtual acetabular cup.

The patient finally chose a 52MM acetabular cup

Step 3: Obtain the centerline of the acetabular cup, pass through the center of the virtual femoral head, rotate the three-dimensional direction of the pelvis vertically by 45 degrees, and tilt forward by 15 degrees.

Step 4: Make an acetabular radius of 26 mm from the center of the acetabular cup and add the length of the shortest screw of 20 mm to obtain an imaginary screw of 46 mm. The screw that leaks out of the bone is a non-safe distance screw.

Step 5: The diameter of the pelvis is 52mm, and the excess bone is removed to make a semicircular cup with a diameter of 52mm and a limit mark. The intersection position between the hemispherical cup and the driveable screw is the safe range of 2CM screw.

Step 6: Select the fitting surface at the limit mark, and fit the bone surface during the operation to fix the position of the hemispherical cup.

step seven

A round rod is made parallel to the centerline of the acetabular cup on the fitting surface guide, and a Kirschner wire can be inserted during the operation to guide the direction of the bone grinding.

step eight

On the outer arc limit ring of the left parallel hemispherical cup on the fitting guide plate, determine the direction and depth of bone grinding.

After the above design is completed, start to print the product (model + guide plate). The final product is shown in Figure 2.

Operation

Conventional approach to any hip joint→expose the upper border of the acetabulum→find the bony landmarks planned before operation→install the acetabular guide plate→grind the acetabulum→install the acetabular screw guide plate and mark it→check→place the acetabular cup product→place the acetabular screw → Subsequent steps are the same as conventional surgery steps

Table 1: Advantages of "this method" compared with "navigation technology":

Table 2: Advantages of "this method" over "pure 3D printing" (currently there are many reports on 3D printing of bone models after 3D reconstruction):

The above is only a specific implementation of the present invention, but the scope of protection of the present invention is not limited thereto, and any changes or replacements that do not come to mind through creative work shall be covered within the scope of protection of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope defined in the claims.

Claims (4)

1. the preparation method of a kind of acetabular bone side form type based on three-dimensional reconstruction and guide plate is it is characterised in that include following walking Suddenly：

Step one, the hip joint three dimensional CT data before operation in patients is processed after set up Digital Three-Dimensional data model, rebuild Acetabular bone side three-dimensional bony structure, reduces disease reset condition；

Wherein, the concrete operations setting up Digital Three-Dimensional data model after hip joint three dimensional CT data being processed are：Image Importing → threshold value division → Three-dimension Reconstruction Model generation → CAD → 3D printing；

Step 2, by analyzing acetabular bone position, assessment acetabular bone state, clear and definite Periacetabular bone amount and to calculate Periacetabular bone thick Degree, formulates acetabular bone burr and scheme inserted by acetabular bone screw, and carries out three-dimensional modeling to these guide plates and model；

Step 3, made using 3D printer preoperative acetabular bone side seam model, grinding mortar guide plate in art, in art acetabular bone screw guide plate and Postoperative acetabular bone side seam model；

Wherein, the material making model adopts medical macromolecular materials, specially nylon material FS3200PA；

Step 4, above-mentioned guide plate and model integration are simultaneously checked, if unqualified, redesign, if qualified, guide plate and model are disappeared Operation is put into after poison.

2. according to claim 1 a kind of based on the acetabular bone side form type of three-dimensional reconstruction with the preparation method of guide plate, its It is characterised by, in described step one, after hip joint three dimensional CT data is processed, set up the tool of Digital Three-Dimensional data model Gymnastics is made to comprise the steps：

1) image imports：

Support the three-dimensional reconstruction software of the thin layer scanning image of dicom standard using mimics and E-3D；By patient pass through CT or View data after person MRI inspection, exports as the image of DICOM format；

2) threshold value divides：

The gray value reaction of CT scan image is the differential declines coefficient for x-ray for the tissue；Threshold segmentation method is based on ash The a kind of of degree image calculates operation, and the tissue in the range of given threshold is retained, and others are removed；

3) Three-dimension Reconstruction Model generates：

In MIMICS and E-3D software, then it is object to be described by the volume data of three-dimensional primitive, by tomoscans such as CT After equipment obtains the volume data of sufferer, obtain the three-dimensional mask of object by Threshold segmentation, calculated based on three-dimensional mask three-dimensional The process of model is exactly three-dimensional reconstruction；

4) CAD：

According to the actual conditions of sufferer threedimensional model, carry out virtual operation design；By CAD, 3-matic, MAGICS etc. assist Instrument or Software for Design go out suitable guide plate or implant etc., participate in surgical procedure, and auxiliary doctor is performed the operation；

5) 3D printing：

3D printing technique is also named increment manufacture, refers to be directly driven by mathematical model, with metal, plastics, pottery, resin, wax, Paper, sand etc. can jointing material, carry out the technology of structural physical entity in quickly shaping device by way of being successively superimposed；Three Rapid forming equipment put into by the dimension sufferer model rebuild and the guide plate model designing, and finally gives 1:1 entity.

3. according to claim 1 a kind of based on the acetabular bone side form type of three-dimensional reconstruction with the preparation method of guide plate, its It is characterised by, in described step 2, the concrete measuring method of bone amount and bone thickness is：

Because the mathematical model after three-dimensional reconstruction is in Threshold segmentation, part cancellous bone is had not extract, thus finally draw three Dimension module has a lot of cavities；By three-dimensional software, model is repaired, after filling-up hole, can select to need the local survey of measurement The volume of amount threedimensional model, thus draw bone amount；

By three-dimensional softwares such as MAGICS, directly select two points of the front and rear wall of model, be exactly that bone is thick at the distance between 2 points Degree.

4. according to claim 1 a kind of based on the acetabular bone side form type of three-dimensional reconstruction with the preparation method of guide plate, its It is characterised by, in described step 4, specific test stone is：The very first time out will in 3D printing for all guide plates and model Accept " detection whether product and design drawing coincide ", using artificial judgment, the such as proterties such as the shape of fruit product, structure, quality Unqualified, then reprocessed and improved, serious failure is then remake product after adjusted design parameter；

Will " acetabular bone screw guide plate and postoperative acetabular bone side seam model in grinding mortar guide plate in preoperative acetabular bone side seam model, art, art " Carry out surgical simulation test successively, observe and whether can correctly swimmingly combine, if there are not smooth between each guide plate and each model Situation, then reprocess, or remake.