A method for constructing a femoral neck fracture personalized bone graft guide

Abstract

The application provides a construction method of a femoral neck fracture personalized bone grafting guide, and belongs to the technical field of digital medicine, and comprises the following steps: 1, three-dimensional reconstruction; 2, virtual reduction; 3, determining a bone grafting point; 4, determining a bone attachment surface; using the uniform offset tool of 3-matic, the extracted bone attachment surface is uniformly offset by 1-2 mm to the outside (namely, in the direction opposite to the relative bone surface), a fitting part is generated; 5, determining a bone grafting path; 6, generating a Kirschner wire sleeve based on the diameter of the Kirschner wire, and further generating a bone grafting guide. The application realizes effective bone support for the femur by attaching the fitting part to the back of the greater trochanter side of the femur of the patient, and generates a Kirschner wire guide sleeve. By using the bone grafting guide, the Kirschner wire can be accurately guided to the bone defect area, namely the bone grafting target area, in the closed reduction surgery of the femoral neck fracture.

Description

Technical Field

[0001] This invention belongs to the field of digital medical technology, and in particular relates to a method for constructing a personalized bone grafting guide for femoral neck fractures. Background Technology

[0002] Femoral neck fractures are often accompanied by bone defects at the fracture site. The location and size of the bone defect directly affect the healing of the fracture, nonunion, and the incidence of femoral head necrosis. Furthermore, bone defects in different locations will cause corresponding changes in the surface stress of the implant.

[0003] The most direct way to address bone defects is through bone grafting. Currently, commonly used femoral neck grafting methods include bone flap transplantation and bone marrow transplantation. The former includes vascularized bone flaps and muscularized bone flaps. Their advantages are that they provide bony support to the defect site and have their own blood supply. The disadvantages are that they require open surgery, which can damage the donor site, and they may not match the donor's shape, leading to increased surgical scope, time, and blood loss. They also require a high level of microsurgical skill from the surgeon. The latter method allows for minimally invasive procedures, but it cannot provide effective bony support to the femur or precisely locate the defect.

[0004] Therefore, there is a need for a method to construct a bone graft guide that can provide effective bony support to the femur and accurately locate the defect site. Summary of the Invention

[0005] The purpose of this invention is to provide a method for constructing a personalized bone grafting guide for femoral neck fractures, characterized by the following steps:

[0006] Step 1: Use the Mimics bone segmentation tool to initially segment the pelvis, healthy femur, affected femoral head, and affected femoral shaft; use the multi-layer editing tool and cavity filling tool to segment and fill the image along the outer contours of the affected femoral head, affected femoral shaft, and healthy femur; use the solid creation tool to 3D reconstruct the four bony structures of the pelvis, healthy femur, affected femoral head, and affected femoral shaft, and save them as STL format files respectively.

[0007] Step 2: Import the four generated STL files into the post-processing software. Select the coccyx and pubic symphysis points on the pelvic bone file to determine the optimal mirror plane. Mirror the patient's healthy femur to the opposite side along this optimal mirror plane, and record this as the healthy femur mirror file. Use the automatic registration tool based on the ICP algorithm, with the healthy femur mirror file as the source point cloud Q1 and the patient's femur shaft file as the target point cloud P1, register and reset the affected femur shaft onto the healthy femur mirror file, and record this as the affected femur shaft reset file. Use the lasso tool to extract the femoral head concave area from the mirror surfaces of the affected and healthy femurs, and record these as the affected femoral head concave and healthy mirror femoral head concave files, respectively. Use the automatic registration tool based on the ICP algorithm, with the healthy mirror femoral head concave file as the source point cloud Q2 and the affected femoral head concave file as the target point cloud P2, register the affected femoral head to the healthy mirror femoral head concave file, and record this as the affected femoral head reset file.

[0008] Step 3: Using measuring tools, take multiple points on the edge of the femoral shaft on the affected side, measure the shortest distance from each point to the edge of the femoral head on the affected side, and take the midpoint of the longest distance among the multiple shortest distances as the target point for bone grafting;

[0009] Step 4: The small lateral incision for femoral neck cannulated screw placement is usually located slightly below and posteriorly to the greater trochanter. Therefore, the bone graft guide and the femoral neck screw placement share the same surgical incision. Based on this, the bony surface area on the posterolateral side of the greater trochanter is designated as the bone attachment surface. Using the 3-matic uniform offset tool, the bone attachment surface is uniformly offset 1-2 mm in the opposite direction to the bony surface to create the attachment area.

[0010] Step 5: Using the target bone graft point as the endpoint, calculate the distance from that point to each point on the bone grafting surface. To ensure that as much bone as possible is implanted during the bone grafting surgery, the point with the longest distance is taken as the starting point of the bone graft, and the line connecting the starting point of the bone graft and the target bone graft point is taken as the bone graft path.

[0011] Step 6: Select a Kirschner wire with a diameter of 2.5 mm. Using the bone graft path as the axis, generate a Kirschner wire sleeve with an inner diameter of 2.6 mm, a wall thickness of 1 mm, and a length of 10-15 mm. This sleeve is used to guide the insertion of the Kirschner wire during the operation. Fixation holes are reserved on the fitting part to complete the construction of the bone graft guide.

[0012] Compared with existing technologies, the main advantages of this invention are as follows: This invention proposes a design method for a personalized bone graft guide that can be used in closed reduction surgery for femoral neck fractures. The bone graft guide designed based on this method has its inner surface attached to the posterolateral aspect of the greater trochanter of the patient's femur, providing effective bony support to the femur. It also incorporates a Kirschner wire guiding sleeve, allowing for precise guidance of Kirschner wires to the bone defect area during closed reduction surgery for femoral neck fractures. Attached Figure Description

[0013] Figure 1 This is a flowchart illustrating the construction method of a personalized bone grafting guide for femoral neck fractures according to the present invention.

[0014] Figure 2 This is a schematic diagram of the three-dimensional reconstruction of the four bony structures of the pelvis, healthy femur, affected femoral head, and affected femoral shaft in step two of this invention.

[0015] Figure 3 This is a schematic diagram of the healthy femur image file in the method of the present invention.

[0016] Figure 4 This is a schematic diagram illustrating the confirmation of bone graft sites in the method of the present invention.

[0017] Figure 5 This is a schematic diagram showing the position of the bone apposition surface in the method of the present invention.

[0018] Figure 6 This is a schematic diagram of the bonding portion generation in the method of the present invention.

[0019] Figure 7 This is a schematic diagram showing the connection between the target bone graft point and each point on the bone adhesion surface in the method of the present invention.

[0020] Figure 8 This is a schematic diagram illustrating the confirmation of the bone graft path in the method of the present invention.

[0021] Figure 9 This is a schematic diagram showing the interaction between the generated bone graft guide and the posterior aspect of the greater trochanter of the femur.

[0022] Figure 10 This is a schematic diagram of the bone graft guide generated by the present invention. Detailed Implementation

[0023] The following will describe in more detail, with reference to the schematic diagram, a method for constructing a personalized bone graft guide for femoral neck fracture according to the present invention, wherein the preferred embodiments of the present invention are shown. It should be understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the present invention.

[0024] like Figure 1 As shown, a method for constructing a personalized bone grafting guide for femoral neck fractures includes the following steps:

[0025] Step 1: Morphological reconstruction of the patient's pelvis, femur, femoral head, and femoral shaft.

[0026] 1): Acquire the patient's CT imaging data and read the data using 3D reconstruction software;

[0027] 2): (This patent uses Mimics as an example). Using the Mimics bone segmentation tool, with a threshold of 180-200 HU, the pelvis, healthy femur, affected femoral head, and affected femoral shaft are initially segmented;

[0028] 3): Use the multiple slice edit tool and the cavity fill tool to segment and fill the image along the outer contour of the affected femoral head, affected femoral shaft, and healthy femur;

[0029] 4): Use the Calculate Part tool to 3D reconstruct the four bony structures: pelvis, healthy femur, affected femoral head, and affected femoral shaft, and save them as STL format files respectively.

[0030] Step 2: Virtual Reset

[0031] 1) Import the four generated STL files into the post-processing software 3-matic. Select points such as the coccyx and pubic symphysis on the pelvic file to determine the optimal mirror plane. Then, mirror the patient's healthy femur to the opposite side along this optimal mirror plane, and record it as the healthy femur mirror file. Figure 2 As shown.

[0032] 2): Based on the image file of the healthy femoral head, generate the femoral shaft reduction file and the femoral head reduction file of the affected side.

[0033] 1: Using the ICP-based automatic registration (Global Registration) tool, with the healthy femur image file as the source point cloud Q1 and the patient's femur shaft file as the target point cloud P1, the affected femur shaft is registered and repositioned onto the healthy femur image file, and recorded as the affected femur shaft repositioning file;

[0034] 2: Use the Lasso area mask tool to extract the femoral head fossa area on the mirror surface of the affected femoral head and the healthy femoral head, and record them as the affected femoral head fossa and the healthy mirror femoral head fossa file, respectively.

[0035] 3. Using an automatic registration tool based on the ICP algorithm, with the concave head of the healthy side as the source point cloud Q2 and the concave head file of the affected side as the target point cloud P2, the affected femoral head is registered to the concave head file of the healthy side, following the concave head file of the affected side. This is recorded as the affected femoral head repositioning file. Figure 3 As shown.

[0036] Step 3: Determine the bone graft site

[0037] Using a measuring tool, take several points along the edge of the femoral shaft on the affected side and measure the shortest distance from each point to the edge of the femoral head on the affected side, as shown below. Figure 4 As shown, P1, P3, P5, and P7 are points on the edge of the femoral shaft on the affected side, and P2, P4, P6, and P8 are the points closest to the edge of the femoral head on the corresponding affected side. Among them, the line connecting P7 and P8 is the longest, and the midpoint of the line connecting P7 and P8 is the target point C for bone grafting.

[0038] Step 4: Determine the bone adhesion surface

[0039] (Note: Explanation of the selection principle for bone graft attachment) The small lateral incision for femoral neck cannulated screw placement is usually located slightly below and posteriorly to the greater trochanter. Therefore, in this patent, the bone graft guide and the femoral neck screw placement share the same surgical incision. Extraction as... Figure 5 As shown, the bony surface region on the posterior side of the greater trochanter of the femur, denoted as the "bone attachment surface," is uniformly offset 1 to 2 mm laterally (i.e., in the opposite direction to the bony surface) using the 3-matic uniform offset tool to generate the attachment portion, as shown. Figure 6 As shown.

[0040] Step 5: Determine the bone graft path

[0041] (Note: Determine the bone graft path) Using the target bone graft point C as the endpoint, calculate the distance from point C to each point on the bone apposition surface, as follows: Figure 7 As shown, the lines CS1, CS2, CS3, and CS2 are connected. 4…… CS n To ensure that as much bone as possible is implanted during the bone grafting surgery, this patent preferentially selects the point on the bone apposition surface with the longest distance to the target bone graft point C as the starting point for the bone graft, and uses the line connecting the starting point and the target bone graft point C as the bone graft path, as follows: Figure 8 As shown

[0042] Step Six: Generate the Bone Graft Guide

[0043] (Note: Briefly describe the parameters for generating the guide plate) In this patent, a Kirschner wire with a diameter of 2.5 mm is preferred. Using the bone graft path determined in the previous step as the axis, a Kirschner wire sleeve with an inner diameter of 2.6 mm, a wall thickness of 1 mm, and a length of 10-15 mm is generated to guide the insertion of the Kirschner wire during the procedure. A fixation hole with a diameter of xx mm is pre-drilled in the fitting area, such as... Figure 9 and 10 As shown.

[0044] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A method of constructing a femoral neck fracture personalized bone graft guide, characterized by, It comprises the following steps: S1: obtaining CT data of a patient, reading the data using three-dimensional reconstruction software, and performing three-dimensional reconstruction on the patient's pelvic bone, healthy femur, affected femoral head and affected femoral shaft; S2: selecting multiple points in the pelvic bone, determining the best mirror surface, generating a healthy mirror femoral head concave file based on the best mirror surface, and registering the affected femoral head to the healthy mirror femoral head concave file following the affected femoral head concave region; S3: using a measuring tool, taking multiple points on the edge of the affected femoral shaft, measuring the shortest distance from each point to the edge of the affected femoral head, and taking the midpoint of the longest distance as the bone graft target point; S4: setting the bony surface area behind the greater trochanter as the bone attachment surface, and generating a fitting part based on the bone attachment surface; S5: taking the bone graft target point as the endpoint, calculating the distance from the point to each point on the bone attachment surface, and taking the point with the longest distance as the bone graft starting point, and taking the line connecting the bone graft starting point and the bone graft target point as the bone graft path; S6: taking the bone graft path as the axis, generating a Kirschner wire sleeve, and completing the construction of the bone graft guide.

2. The method of constructing a femoral neck fracture personalized bone graft guide according to claim 1, characterized in that, In S1, the three-dimensional reconstruction specifically comprises the following steps: S11: using Mimics bone segmentation tool to preliminarily segment the pelvic bone, healthy femur, affected femoral head and affected femoral shaft; S12: using multi-layer editing tool and cavity filling tool to perform image segmentation and filling along the affected femoral head, affected femoral shaft, healthy femur outer contour; S13: using the create entity tool to three-dimensionally reconstruct the four bony structures of the pelvic bone, healthy femur, affected femoral head and affected femoral shaft, and saving them as STL format files respectively.

3. The method of constructing a femoral neck fracture personalized bone graft guide according to claim 1, characterized in that, S2 specifically comprises the following steps: S21: importing the four generated STL format files into the post-processing software, selecting the coccyx and pubic symphysis points on the pelvic bone file, determining the best mirror surface, and mirroring the patient's healthy femur to the opposite side along the best mirror surface, denoted as the healthy femur mirror file; S22: using the automatic registration tool based on ICP algorithm, taking the healthy femur mirror file as the source point cloud Q1 and the patient's femoral shaft file as the target point cloud P1, registering and reducing the affected femoral shaft to the healthy femur mirror file, denoted as the affected femoral shaft reduction file; S23: using the lasso tool to extract the femoral head concave region of the affected femoral head and the healthy femur mirror surface respectively, denoted as the affected femoral head concave and the healthy mirror femoral head concave files respectively; S24: using the automatic registration tool based on ICP algorithm, taking the healthy mirror femoral head concave file as the source point cloud Q2 and the affected femoral head concave file as the target point cloud P2, and making the affected femoral head follow the affected femoral head concave file and register to the healthy mirror femoral head concave file, denoted as the affected femoral head reduction file.

4. The method of constructing a femoral neck fracture personalized bone graft guide according to claim 1, characterized in that, In S4, the uniform offset tool of 3-matic is used to uniformly offset the bone attachment surface to the opposite direction of the relative bony surface by 1-2mm, generating the fitting part.

5. The method of constructing a femoral neck fracture personalized bone graft guide of claim 1, wherein, The S6 is specifically: selecting a Kirschner wire with a diameter of 2.5 mm, taking the bone grafting path as an axis, generating a Kirschner wire sleeve with an inner diameter of 2.6 mm, a wall thickness of 1 mm, and a length of 10-15 mm, for guiding the placement of the Kirschner wire during the operation, and reserving a fixing hole at the fitting part, to complete the construction of the bone grafting guide.

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