This publication was supported by the Beijing Municipal Natural Science Foundation (L192059).

All data come from the clinical patient, whose SDR operation was carried out at BJ Dongzhimen Hospital. The protocol follows the guidelines of and was approved by the Dongzhimen Hospital research ethics committee.
NOTE: The whole map of the model reconstruction protocol is shown in Figure 1. The high-resolution computed tomography (HRCT) data and Dixon data are raw materials for modeling; then, the 3D model creation consists of image registration and fusion. The f...

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This study provides a workflow for establishing a preoperative 3D printing model of the lumbar spine in patients with cerebral palsy, with the aim of facilitating preoperative planning for SDR surgery and enhancing anatomical training based on the patient's specific model. The study aims to establish a highly reliable 3D-printed model that accurately demonstrates the patient's lumbar vertebral and nerve structures. By measuring the position of the lamina and spinal nerve in the model before surgery, precise planning of t...

Spastic cerebral palsy affects over half of all children with cerebral palsy1, leading to tendon contractures, abnormal skeletal development, and decreased mobility, greatly impacting the quality of life of affected children2. As the main surgical method for the treatment of spastic cerebral palsy, selective dorsal rhizotomy (SDR) has been fully validated and recommended by many countries3,4. However, the intricate and high-risk nature of SDR surgery, including the precise cutting of the lamina, positioning and dissociation of nerve roots, and severing of nerve fibers, presents a significant challenge for young doctors who are just beginning to engage with SDR in clinical practice; further, the learning curve of SDR is very steep.
In traditional orthopedic surgery, surgeons must mentally integrate all preoperative two-dimensional (2D) images and create a 3D surgical plan5. This approach is particularly difficult for preoperative planning involving complex anatomical structures and surgical manipulations, such as SDR. With advances in medical imaging and computer technology, 2D axial images, such as computed tomography (CT) and magnetic resonance imaging (MRI) can be processed to create 3D virtual models with patient-specific anatomy6. With improved visualization, surgeons can analyze this processed information to make more detailed diagnoses, planning, and surgical interventions tailored to the patient&#39;s condition. In recent years, the application of multimodal image fusion technology in orthopedics has gradually attracted attention7. This technology could fuse CT and MRI images, greatly improving the accuracy of the digital3D analog model. However, the application of this technique in preoperative models of SDR has not been researched yet.
Accurate positioning of the lamina and spinal nerve and precise cutting during SDR surgery are crucial for successful outcomes. Typically, these tasks rely on experts&#39; experience and are confirmed repeatedly by a C-arm during the operation, resulting in a complex and time-consuming surgical process. The 3D digital model serves as the foundation for future SDR surgical navigation and can also be utilized for preoperative planning of laminectomy procedures.&#160;This model fuses the bone structure from CT and the spinal nerve structure from MRI, and assigns different colors to the lumbar vertebra sections marked for cutting according to the surgical plan. Such holographic 3D printing models for SDR not only facilitate preoperative planning and simulation, but also output accurate 3D navigation coordinates to the intraoperative robotic arm for precise cutting.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>J55 Prime 3D-Printer</td>
			<td>Stratasys</td>
			<td>J55 Prime</td>
			<td>Manufacturing the model</td>
		</tr>
		<tr>
			<td>MATLAB</td>
			<td>MathWorks&#160;</td>
			<td>2022B</td>
			<td>Computing and visualization&#160;</td>
		</tr>
		<tr>
			<td>Mimics</td>
			<td>Materialise</td>
			<td>Mimics Research V20</td>
			<td>Model format transformation</td>
		</tr>
		<tr>
			<td>Tools for volum fusion</td>
			<td>Intelligent Entropy</td>
			<td>VolumeFusion V1.0</td>
			<td>Beijing Intelligent Entropy Science &#38; Technology Co Ltd. 
			Modeling for CT/MRI fusion</td>
		</tr>
	</tbody>
</table>

3d printing model of a patient's specific lumbar vertebra

Selective dorsal rhizotomy (SDR) is a difficult, risky, and sophisticated operation, in which a laminectomy should not only expose an adequate surgical field of view but also protect the patient&#39;s spinal nerves from injury. Digital models play an important role in the pre-and intra-operation of SDR, because they can not only make doctors more familiar with the anatomical structure of the surgical site, but also provide precise surgical navigation coordinates for the manipulator. This study aims to create a 3D digital model of a patient-specific lumbar vertebra that can be used for planning, surgical navigation, and training of the SDR operation. The 3D printing model is also manufactured for more effective work during these processes.
Traditional orthopedic digital models rely almost entirely on computed tomography (CT) data, which is less sensitive to soft tissues. Fusion of the bone structure from CT and the neural structure from magnetic resonance imaging (MRI) is the key element for the model reconstruction in this study. The patient&#39;s specific 3D digital model is reconstructed for the real appearance of the surgical area and shows the accurate measurement of inter-structural distances and regional segmentation, which can effectively help in the preoperative planning and training of SDR. The transparent bone structure material of the 3D-printed model allows surgeons to clearly distinguish the relative relationship between the spinal nerve and the vertebral plate of the operated segment, enhancing their anatomical understanding and spatial sense of the structure. The advantages of the individualized 3D digital model and its accurate relationship between spinal nerve and bone structures make this method a good choice for preoperative planning of SDR surgery.

Based on lumbar CT/MRI image fusion data in children with cerebal palsy, we created a representative model of the lumbar spine combined with spinal nerves. High-pass filtering was used to extract the high signal in the CT value range of 190-1,656 from HRCT, so as to achieve the reconstruction of the bone structure of the lumbar spine in the operation area. Spinal nerve structures were reconstructed by the high-pass filtering of Dixon-w sequences in MRI. The digital model and point cloud data coordinates of the lumbar ver...

Watch this Scientific Journal Video about 3D Printing Model of a Patient's Specific Lumbar Vertebra at JoVE.com

3D Printing Model of a Patient&#039;s Specific Lumbar Vertebra

This study aims to create a 3D-printed model of a patient-specific lumbar vertebra, which contains both the vertebra and spinal nerve models fused from high-resolution computed tomography (HRCT) and MRI-Dixon data.

3D Printing Model of a Patient's Specific Lumbar Vertebra

Selective dorsal rhizotomy (SDR) is a difficult, risky, and sophisticated operation, in which a laminectomy should not only expose an adequate surgical ...

The protocol has fills the complex CT and MRI images of human anatomical structures, leveraging the respectively advantage of both type of imaging. This is a significant innovation in the field of medical imaging. In the fused model, doctors can view both bone structure from CT and softer tissue structures from MRI.Additionally, the 3D model can be used for precise 3D navigation of surgical robots. This technology is applicable to almost all seniors that require multimodal fusion, such as ultrasonic image fusion. The 3D fusion model is also of great significance for pre-arbitral planning and the post-arbitral evaluation.When using this technology, you will have insight from multimodal imaging simultaneously. Different dimension perspective will unfold synchronously, and the diagnostic and therapeutic process will evolve. To begin, set the data resources from the CT machine station.Open the single CT 2012 B software to receive data from the scanning protocol SpineRoutine_1. Use a slice thickness of one millimeter with a matrix size of 512 pixels by 512 pixels, in which the pixel spacing is 0.3320 millimeters. The actual size of the 3D volume achieved is 512 by 512 by 204 voxels.Call the Dicom2Mat subprocess in the MATLAB workplace to obtain the 3D volume from the DICOM files stored in the HRCT data folder. View each slice within the 3D volume through the graphical user interface or GUI. Then visualize the intensity distribution of the vertebrae HRCT data by the heist function.Call the noise clean subprocess to delete signal noise formed by the device under the HRCT data file parts. And use the vertebrae function subprocess under the same path, to gain the vertebrae model which is also a 3D volume, but only with the bone structure. Use the high-pass filter parameters and the intensity range from 190 to 1, 656.Use the Dicom2Mat subprocess in both parts of the Dixon-In and Dixon_W sequences, and get their 3D volume. Visualize each individual slice that constitutes a 3D volume and access this visualization once the Dicom2Mat subprocess has been completed. Use the spinal nerve function to reconstruct the spinal nerve model with high-pass filter parameters and the intensity range from 180 to 643.Filter out points with low intensity to extract the spinal nerve 3D volume as the nerve signals in the Dixon_W sequence are very high. Once the spinal nerve subprocess is finished check the model generated in the GUI. Copy the three 3D volumes to the file path of the project.The models from HRCT and DIXON-In include the same vertebrae structure. And the models from DIXON-In and Dixon_W have the same coordinates. Put the three models file names into the vertebrae fusion subprocess as an input to generate the fusion model.If fine tuning is necessary from the doctor's perspective, add coordinate parameters in all directions to the same function to correct the fusion model. If slight errors are observed in fusion from a clinical perspective, use the vertebra fusion function to fine tune the fusion coordinates. This process involves parameter adjustments to the six dimensions of coordinate direction.Make a separate folder in the project directory for outputting the result of the fusion model. Export the fusion models to be used for 3D printing in the DICOM format sequences under the file path of the fusion directory. Utilize the mat2dicom algorithm to execute the export operation.by inputting the fusion model. Open the DICOM file sequence exported previously using Materialise Mimics version 20 to perform the export operation. Navigate to the export menu under the file tab and select the VRML format.The file path for the export can be freely customized according to the user's requirements. As transparent colorful 3D printing is a professional service, compress and pack the VRML files and send them to the service provider. The multimodal fusion model of CT and MRI is used for preoperative planning and training in Selective Dorsal Rhizotomy or SDR.The GUI of slices in the volume from the HRCT data is shown in this figure. Through this GUI, surgeons can view the spine structure contained in all the CT data. The graphical image shown here represents the intensity distribution of vertebrae HRCT data.This quantitative information helps to determine the filtering range of vertebrae structure. The 3D printing model for Selective Dorsal Rhizotomy or SDR planning and training is shown in this image. Different colored dyes are used to disdain and distinguish the structures, such as bones and nerves.The spinal nerve structure is dyed yellow and the lamina of L4 and L5 segments in the corresponding operation area, are distinguished by red and blue staining. The bone structure is printed using a transparent resin material, which allows the doctors to observe the nerve structure under the lamina through the bone structure. Equivalent, insensitive, or multimodal fusion technology is bound to bring various new applications as doctors can obtain information from different dimensions in one model.Medical imaging based diagnostic treatment and the surgical navigation are the main battlegrounds for multimodal fusion technology in the field of medical imaging.

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1.6K Views.  Beijing University of Chinese Medicine. The protocol has fills the complex CT and MRI images of human anatomical structures, leveraging the respectively advantage of both type of imaging. This is a significant innovation in the field of medical imaging. In the fused model, doctors can view both bone structure from CT and softer tissue structures from MRI.Additionally, the 3D model can be used for precise 3D navigation of surgical robots. This technology is applicable to almost all seniors that require multimodal fusion, such...