3D printing guide plate for extracting bone from autologous ilium and reconstructing bone defect as well as preparation method and application of 3D printing guide plate

Abstract

The invention relates to the technical field of bone defect reconstruction, in particular to a 3D printing guide plate for autologous iliac bone extraction and bone defect reconstruction and a preparation method and application of the 3D printing guide plate for autologous iliac bone extraction and bone defect reconstruction. Tumor excision is simulated in a computer, and a bone defect area three-dimensional model is generated; according to the bone defect area model, the optimal ilium taking position, size, shape and bone taking scheme are determined through computer aided design; designing a bone taking guide plate and a fixing guide plate according to the bone taking scheme, wherein the guide plate is prepared through a 3D printing technology. According to the method, key steps (such as tumor resection simulation, bone taking scheme design and bone grafting fixation simulation) of bone defect reconstruction are all completed under the assistance of a computer, a standardized operation process is formed, and a standardized solution for bone defect reconstruction is constructed.

Description

Technical Field

[0001] This invention relates to the field of bone defect reconstruction technology, specifically to a 3D-printed guide plate for reconstructing bone defects using autologous iliac bone, its preparation method, and its application. Background Technology

[0002] Following the resection of bone and soft tissue tumors, patients often experience large-area bone defects in their limbs, directly impacting motor function and quality of life. There is an urgent clinical need for a reconstruction method that can provide both initial mechanical strength and promote bone healing. Autologous iliac bone grafting, due to its excellent biocompatibility and low risk of immune rejection, has become a classic method for bone defect repair, offering advantages such as satisfactory initial strength and a high healing rate.

[0003] Despite the significant clinical efficacy of autologous iliac bone grafting, traditional surgical methods suffer from two major technical bottlenecks: insufficient precision in bone harvesting. During iliac bone harvesting, surgeons rely on experience to determine the location, size, and shape of the bone, lacking quantitative guidance standards. This subjective approach easily leads to insufficient bone harvesting, requiring secondary harvesting, prolonging surgical time, and increasing the risk of infection; excessive bone harvesting can damage the iliac bone structure, causing donor site complications (such as pain and fractures); and mismatch between the bone graft shape and the defect area affects graft stability. Poor reliability of bone graft fixation. After iliac bone graft implantation, its placement and fixation method depend on the surgeon's immediate judgment, lacking preoperative planning. Deviations in bone graft orientation can lead to abnormal force transmission, causing stress concentration in the graft area; improper screw placement can damage surrounding blood vessels and nerves; and cannulated screw fixation requires multiple adjustments to the guide pin angle, increasing surgical complexity. These problems result in a higher risk associated with traditional surgery, potentially requiring secondary corrective surgeries due to improper bone harvesting or fixation.

[0004] With the development of digital medicine and additive manufacturing technology, 3D-printed surgical guides are gradually being used in orthopedic surgery. Existing technologies can reconstruct bone models using CT data, but precise guidance throughout the entire bone harvesting and grafting process has not yet been achieved. This invention provides a standardized solution for bone defect reconstruction by integrating preoperative planning, guide design, and intraoperative execution. Summary of the Invention

[0005] The purpose of this invention is to provide a 3D-printed guide plate for reconstructing bone defects using autologous iliac bone, its preparation method, and its application. This method completes the key steps of bone defect reconstruction (such as tumor resection simulation, bone harvesting scheme design, and bone graft fixation simulation) with computer assistance, forming a standardized operating procedure and constructing a standardized solution for bone defect reconstruction.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] This invention provides a method for preparing a 3D-printed guide plate for reconstructing bone defects using autologous iliac bone, comprising the following steps:

[0008] (1) Based on the DICOM data of the patient's tumor site and pelvis CT scan, the tumor was resected in the computer and a three-dimensional model of the bone defect area was generated.

[0009] (2) Based on the bone defect area model, the optimal iliac bone harvesting location, size, shape and harvesting plan are determined by computer-aided design. The iliac bone harvesting plan should ensure that all harvested iliac bone pieces are used for reconstruction (no waste principle) and that the shape of the area to be reconstructed can be completely filled with the fewest number of iliac bone pieces (1-2 pieces) (matching principle).

[0010] (3) Based on the bone harvesting scheme, a bone harvesting guide plate and a fixation guide plate are designed. The guide plate is prepared by 3D printing technology.

[0011] Furthermore, in step (1), the slice thickness of the CT scan is 1 mm, and the three-dimensional model is generated by volumetric reconstruction technology.

[0012] Furthermore, in step (2), the shape of the bone harvesting guide plate matches the anatomical structure of the iliac crest and the outer plate of the iliac bone; the bone harvesting guide plate is provided with a saw groove for bone harvesting and a saw groove for processing bone grafts.

[0013] Furthermore, in step (2), the shape of the fixation guide plate matches the shape of the bone graft block, and the fixation guide plate is provided with a reserved nail channel, wherein the nail channel that needs to be fixed with a hollow nail is equipped with a guide pin cap structure.

[0014] Furthermore, in step (2), the bone grafting scheme includes optimization steps for the position, orientation, and matching relationship between the bone graft and the bone defect area.

[0015] The present invention also provides a bone harvesting guide plate prepared using the aforementioned preparation method.

[0016] The present invention also provides a fixed guide plate prepared using the aforementioned preparation method.

[0017] The present invention also provides an application of the bone harvesting guide plate or the fixation guide plate described herein in studies related to autologous iliac bone harvesting for bone defect reconstruction.

[0018] The beneficial effects of this invention are as follows:

[0019] In traditional surgery, the location, size, and shape of iliac bone harvesting are highly dependent on the surgeon's experience, easily leading to problems such as insufficient bone harvesting requiring secondary supplementation or excessive bone harvesting causing damage to the iliac bone structure. This invention uses preoperative CT scans to generate a three-dimensional model of the bone defect area, combined with computer-aided design to precisely plan the bone harvesting scheme, strictly controlling the harvesting error within millimeters. This quantitative control avoids surgical risks caused by improper bone harvesting and significantly reduces the probability of donor site complications. Traditional bone graft fixation relies on the surgeon's immediate judgment, and deviations in bone block orientation can easily lead to abnormal mechanical transmission. This invention uses a fixation guide to pre-set the position and angle of the bone graft, combined with volume reconstruction technology to optimize the matching relationship of the bone defect area, ensuring accurate bone graft orientation and thus guaranteeing mechanical stability. Clinical follow-up shows that the bone graft healing rate and excellent functional recovery rate are significantly improved.

[0020] This invention utilizes computer-aided procedures to complete key steps in bone defect reconstruction (such as tumor resection simulation, bone harvesting plan design, and bone grafting and fixation simulation), forming a standardized operating procedure. Even surgeons with limited experience can complete the surgery following the guide, overcoming the reliance on senior physicians in traditional surgery and promoting the widespread adoption of this technology. Furthermore, the guide design is based on individualized CT data, adaptable to patients of different ages, genders, and bone morphologies. For patients with significant anatomical variations, the guide's elastic deformation structure achieves precise fit, avoiding operational errors caused by anatomical differences and improving surgical success rates. Through precise bone harvesting and bone grafting fixation, patients can begin functional exercises early postoperatively, significantly shortening the rehabilitation period, greatly improving limb function scores, and significantly enhancing quality of life. Simultaneously, the shortened operation time, reduced complications, and compressed rehabilitation period significantly reduce the overall cost per surgery and minimize the waste of medical resources associated with secondary surgeries, demonstrating significant economic and social benefits. Attached Figure Description

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a flowchart illustrating the fabrication process of the 3D-printed guide plate for reconstructing bone defects using autologous iliac bone harvesting in this invention.

[0023] Figure 2 This is a physical image of the 3D-printed guide plate for reconstructing bone defects using autologous iliac bone harvesting in this invention. Detailed Implementation

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] The method for reconstructing bone defects by autologous iliac bone harvesting under the guidance of a personalized 3D-printed guide plate in this invention includes the following steps:

[0030] 1. The resection plan is determined based on the size and nature of the tumor;

[0031] 2. Perform thin-slice CT scans (1 mm slice thickness) on the tumor site and pelvis to obtain DICOM data of the CT scans of the tumor site and pelvis for design and simulation;

[0032] 3. DICOM data of the tumor site are reconstructed using volume, and the resection is simulated on a computer to determine the bone defect area;

[0033] 4. Based on the bone defect area, simulate bone harvesting and reconstruction from the iliac bone. Through multiple trials and adjustments, determine the optimal location, size, and shape for iliac bone harvesting. Based on this harvesting plan, prepare an iliac bone guide plate. The requirements for the iliac bone harvesting guide plate are as follows:

[0034] 1) Determine the location, size, and shape of the bone harvested based on the computer-aided design plan.

[0035] 2) Locating the iliac crest and the outer plate of the iliac bone by matching their shapes;

[0036] 3) In addition to the saw grooves for harvesting bone, the bone harvesting guide plate also has saw grooves for processing the bone graft (integrated guide plate).

[0037] 5. Based on the bone defect area, a simulated reconstruction of the iliac bone block was performed, and after multiple trials and adjustments, the optimal bone grafting plan was determined. Based on this bone harvesting plan, a fixation guide was prepared. The requirements for the fixation guide are as follows:

[0038] 1) The guide plate position is located by matching the shape of the bone graft;

[0039] 2) The guide plate has pre-drilled nail slots, so you can directly screw in the fixing screws;

[0040] 3) For nail tracks that need to be fixed with hollow nails, install a guide pin cap. Place the guide pin cap on the nail track, drive the guide pin through the guide pin cap, remove the guide pin cap, and screw the hollow nail in along the guide pin to complete the fixation.

[0041] Example 1

[0042] I. Patient Case Overview

[0043] Patient information: Male, 16 years old, underwent total calcaneal resection for osteosarcoma of the right calcaneus, and postoperative reconstruction of the bone defect is required.

[0044] II. Preoperative preparation and guide plate design

[0045] 1. Data Acquisition and 3D Modeling

[0046] CT scan parameters: slice thickness 1mm, tube voltage 120kV, tube current 200mA, scan range covering the area from the right foot to the iliac bone.

[0047] 3D Reconstruction: The bone structure was extracted using Mimics 21.0 software to generate a 3D model of the tumor site and pelvis.

[0048] 2. Surgical procedure simulation

[0049] Tumor resection simulation: Virtually remove the entire calcaneus 5mm outside the tumor margin to generate a model of the bone defect area.

[0050] Bone harvesting plan planning:

[0051] The donor site was selected 2 cm posterior to the anterior superior iliac spine, simulating a bone fragment volume of 40 cm³. 3 (10% smaller than the defective area to allow for processing allowance).

[0052] The shape of the bone fragments was adjusted using CAD software to ensure a 92% match with the volume of the bone defect area.

[0053] Bone grafting plan planning:

[0054] The bone fragment model was imported into the bone defect area and rotated to adjust the contact surface matching degree to 88%. The fixation screws were made of bicortical bone (3.5 mm in diameter and 25 mm in length).

[0055] 3. Guide plate design and fabrication

[0056] (1) Removal of bone guide plate

[0057] Structural features:

[0058] It conforms to the anatomical structure of the iliac crest and outer plate of the iliac bone, and achieves rapid fixation through a three-point positioning buckle.

[0059] Integrating two saw grooves:

[0060] Bone harvesting saw groove: 2mm wide, 15mm deep (covering 90% of the full thickness of the iliac bone).

[0061] Grooves for bone grafts: 1.5mm wide, 8mm deep (with machining allowance).

[0062] 3D printing parameters: Stratasys J750 printer, medical photosensitive resin (DSM) 14120), layer thickness 0.1mm, the support structure adopts point support.

[0063] (2) Fixed guide plate

[0064] Structural features:

[0065] It fits perfectly with the shape of the bone graft.

[0066] Two preset nail paths:

[0067] Standard screw placement: 4.0mm in diameter, perpendicular to the bone defect area.

[0068] Hollow nail track: 5.5mm in diameter, equipped with a guide cap (2.0mm inner diameter), the guide cap protrudes 2mm from the guide plate surface.

[0069] 3D printing parameters: Same as bone guide plate, after printing, it is cleaned with isopropanol and cured with ultraviolet light.

[0070] III. Surgical Procedure

[0071] 1. Body position and disinfection

[0072] The patient was placed in a lateral decubitus position with the right foot elevated 15°. The surgical area was routinely disinfected and draped. After bleeding was expelled, a tourniquet (pressure 250 mm Hg) was applied.

[0073] 2. Bone harvesting procedure

[0074] Guide plate positioning: The bone harvesting guide plate is attached to the iliac crest and fixed with three-point positioning clips, requiring the assistance of Kirschner wires.

[0075] Bone harvesting process: The iliac bone is cut along the bone harvesting saw groove using a reciprocating saw (frequency 10,000 times / minute), with the depth controlled to 95%-100% of the full thickness. After removing the guide plate, the bone block is completely removed with a bone chisel and placed in physiological saline for later use.

[0076] 3. Bone grafting and fixation

[0077] Bone block processing: Adjust the shape of the bone block along the saw groove of the bone graft to ensure that it matches the force line of the calcaneal defect area.

[0078] Guide plate positioning: The fixation guide plate is attached to the bone graft block, and the silicone pad is used to adapt to the slight unevenness of the bottom surface of the iliac bone.

[0079] Fixed operation:

[0080] For fixation with conventional screws: use a 3.0mm drill bit to tap along the screw path and screw in two 3.5mm cortical bone screws.

[0081] Hollow nail fixation: Insert the guide pin cap into the hollow nail track, drive the guide pin (1.8mm in diameter) along the inner channel of the cap, and after the C-arm X-ray machine confirms the position, remove the guide pin cap and screw in two hollow nails (5.0mm in diameter) along the guide pin.

[0082] 4. Iliac bone defect reconstruction

[0083] The iliac bone defect was reconstructed using a steel nail cement structure to ensure a flat bone bed.

[0084] 5. Soft tissue reconstruction

[0085] The Achilles tendon insertion and plantar fascia insertion were reconstructed using suture rivets.

[0086] 6. Wound treatment

[0087] Half-tube drainage + VSD to cover the wound, suture the incision, and apply pressure bandage.

[0088] IV. Postoperative Management and Follow-up

[0089] 1. Postoperative management

[0090] Postoperatively, elevate the affected limb, maintain ankle plantar flexion at 15° and fix it with a brace. Remove the VSD device and drainage 7 days postoperatively, and perform routine dressing changes and bandaging locally.

[0091] 2. Follow-up results

[0092] Wound healing: The wound healed satisfactorily 3 weeks after the operation, with no pain in the bone harvesting area and normal appearance.

[0093] Functional recovery: Independent walking 12 weeks post-surgery, MSTS score of 29 (out of 30).

[0094] Imaging assessment: CT scan 6 months postoperatively showed a blurred interface between the bone graft and the host bone, and uniform density in the bone defect area.

[0095] The final results of the technical effect verification of this invention are shown in Table 1.

[0096] Table 1. Verification results of the technical effects of the present invention

[0097] index Traditional surgery Embodiments of the present invention Increase Bone harvesting error ±2.0mm ±0.4mm 80％↓ Bone graft direction deviation >5° 1.8° 64％↓ Surgery time 4.5 hours 2.8 hours 38％↓ Postoperative healing rate 78％ 94％ 21％↑

[0098] Conclusion: This embodiment achieves precision and standardization in calcaneal defect reconstruction through personalized 3D printed guide plates, significantly improving surgical outcomes and patient prognosis, and verifying the clinical feasibility of the technical solution of this invention.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be covered by the scope of the claims of the present invention.

Claims

1. A method for preparing a 3D-printed guide plate for reconstructing bone defects using autologous iliac bone harvested from the iliac crest, characterized in that, Includes the following steps: (1) Based on the DICOM data of the patient's tumor site and pelvis CT scan, the tumor was resected in the computer and a three-dimensional model of the bone defect area was generated. (2) Based on the bone defect area model, the optimal iliac bone harvesting location, size, shape and harvesting plan are determined by computer-aided design; all iliac bone pieces harvested in the harvesting plan are used for reconstruction, and the shape of the area to be reconstructed can be completely filled with the fewest number of iliac bone pieces. (3) Based on the bone harvesting scheme, a bone harvesting guide plate and a fixation guide plate are designed. The guide plate is prepared by 3D printing technology.

2. The method according to claim 1, characterized in that, In step (1), the slice thickness of the CT scan is 1 mm, and the three-dimensional model is generated by volumetric reconstruction technology.

3. The method according to claim 1, characterized in that, In step (2), the shape of the bone harvesting guide plate matches the anatomical structure of the iliac crest and the outer plate of the iliac bone; the bone harvesting guide plate is provided with a saw groove for bone harvesting and a saw groove for processing bone grafts.

4. The method according to any one of claims 1, characterized in that, In step (2), the shape of the fixation guide plate matches the shape of the bone graft block, and the fixation guide plate is provided with a reserved nail channel, wherein the nail channel that needs to be fixed with a hollow nail is equipped with a guide pin cap structure.

5. The method according to any one of claims 1-4, characterized in that, In step (2), the bone grafting scheme includes optimization steps for the position, orientation, and matching relationship between the bone graft and the bone defect area.

6. A bone harvesting guide plate prepared by the preparation method according to any one of claims 1-5.

7. A fixed guide plate prepared by the preparation method according to any one of claims 1-5.

8. The application of the bone harvesting guide plate as described in claim 6 or the fixation guide plate as described in claim 7 in studies related to autologous iliac bone harvesting for bone defect reconstruction.

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