The study was funded by the Beijing Municipal Science &#38; Technology Commission (No.Z181100001718078), China.

The present study was approved by the ethics committee of Beijing Friendship Hospital Capital Medical University.
1. Diagnosis of the osteoporotic vertebral compression fracture (OVCF) by X-ray fluoroscopy, magnetic resonance image (MRI), bone scintigraphy, and symptoms
<ol>
	<li>Identify patients who have OVCF by older patients with back pain, tenderness in the spinous process, paraspinal muscles at back, etc.</li>
	<li>Use posterioanterior X-ray fluoroscopy to check if patient has vertebral compression fracture.</li>
	<li>Use an MRI to diagnosis whether a patient has a newly onset vertebral compression fracture, and determine the target compressed vertebrae. For patients who cannot undergo the MRI, use bone scintigraphy.</li>
	<li>Order PVP treatment for the patient who has an acute vertebral compression fracture and record the Visual Analogue Scale (VAS) score and Oawestry Disability Index (ODI)8. 
	NOTE: There are a few criteria for inclusion: 1) vertebra fractured patient whether having history of a low-energy trauma or not; 2) no history or evidence of metabolic bone disease or cancer; 3) VAS score &#8805; 7; 4) diagnosis as vertebral fracture by X-ray, MRI or bone scintigraphy.</li>
</ol>
2. Preoperative localization of target vertebra
<ol>
	<li>Before the operation, conduct prone computer tomography on the patient with three radiopaque markers placed in the midline of patient&#39;s back skin at the compressed vertebral level. While pressing the most painful part, confirm the target area by x-ray fluoroscopy and a physical examination on the patient&#39;s back.</li>
	<li>Before the prone computer tomography scan, put a gradienter on the patient&#39;s back just inferior to the fixed markers. Record the patient&#39;s body position and then remove it. Have the patient stay in the same position during surgery.</li>
	<li>Save the CT images (1 mm scanning layer thickness, 1 mm layer spacing, and either 90 slices (conventional scanning) or 400 slices (thin slice scanning) in a DICOM format. Put a cotton pad on the patient&#39;s back to ensure that the markers remain until the operation.</li>
</ol>
3. Simulating the percutaneous vertebroplasty procedure in the computer software
<ol>
	<li>Export the CT images in DICOM format into medical imaging processing software (e.g., MIMICS) and select the target slices to reconstruct the compressed vertebra.</li>
	<li>Select Threshold Segmentation to adjust the threshold range for the target vertebra from 125-3071H and create a mask. Press Duplicate Mask to make two masks: Mask A and Mask B.</li>
	<li>Click Mask Edit to erase the target vertebra in Mask A. Then click Boolean Operations to form a new Mask C by using Mask B to minus Mask A. Press Calculate 3D from Mask to reconstruct the target vertebra.</li>
	<li>Simulate PVP via a bilateral transpedicular approach in the software. First, define the Medcad cylinder in the software as the puncture needle model. Define the cylinders as the same length and radius as the puncture needle (a length of 125 mm and a radius of 1.25 mm).</li>
	<li>Simulate the entry point, the entry angle (head inclination angle and abduction angle orientation), and the puncture needle depth for a real PVP with the 3-D views of the target vertebra.</li>
	<li>Adjust the puncture needles to its ideal position by using the Move and Rotate function. Keep needle trajectories consistent with these principles: 1) the puncture needles can extrapolate through the pedicle, preferably in its superior half; 2) the ideal location of the tips is at the point within the anterior one third of the vertebral body on the lateral view.</li>
</ol>
4. Three-dimensional printing guide template
<ol>
	<li>Save all of the 3D template data and send it in the MCS format to a three-dimensional printing company.</li>
	<li>Convert MCS format data into a STL format and design the template using software. Reconstruct the base, which must cling to patient&#39;s back skin, reconstruct the trajectory canal according to all of the parameters, including skin entry points, entry angles and the depth of the two needles&#39; trajectory, print two same templates out for the operation. 
	NOTE: The guide template is made from polylactic acid, which can be sterilized and by low temperature steam disinfection.</li>
</ol>
5. Applying the three-dimensional printing guide template to assist the real PVP operation
<ol>
	<li>Make the patient lie prone on the operation table as for the CT scanning in accordance with the gradienter record. Measure the distance of the three radiopaque markers and draw the outline of the three markers to match the template with the target location.</li>
	<li>Match a skin template along with the skin outline. Insert and press two swabs through the needle&#39;s trajectories on the template to mark the insertion points on the skin. Then remove the template and draw the points as point A and B.</li>
	<li>Remove the template and disinfect the skin. Drape the area and put the tips of two puncture needles at the insertion points (point A and B). Then, use the anteroposterior view of C-arm fluoroscopy to confirm whether the puncture points determined by template are feasible.</li>
	<li>Give the patient local anesthesia by injecting a 5 mL mixture of 1% lidocaine and 1% ropavicaine at each puncture point. Fix another sterilized template on the patient&#39;s back by sterilized film.</li>
	<li>Tap the two needles into the target vertebra slightly via insertions through the guiding cylinders of the template. Verify with the C-arm fluoroscope that the trajectories are suitable for insertion. Make sure that the punctuation is within the pedicles and then tap the needles to advance further until the end of the trajectory.</li>
	<li>When the whole needles are completely inserted into the guiding cylinders, verify with the C-arm fluoroscope that the needle tips have reached their ideal location.</li>
	<li>Inject bone cement into the vertebral body through the needles. Inject 2 mL of bone cement via each trajectory for a total of 4 mL of bone cement to the vertebra.</li>
	<li>Finally, use fluoroscopy to check the distribution of the bone cement within the vertebral body by anteroposterior and lateral views. Stitch the insertions.</li>
</ol>

<ol>
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V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Percutaneous+access+to+the+vertebral+bodies:+a+video+and+fluoroscopic+overview+of+access+techniques+for+trans-,+extra-,+and+infrapedicular+approaches.">Percutaneous access to the vertebral bodies: a video and fluoroscopic overview of access techniques for trans-, extra-, and infrapedicular approaches.</a> World Neurosurgery. 80 (3-4), 428-435 (2013).</li><li>Kaneyama, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+screw+guiding+method+with+a+screw+guide+template+system+for+posterior+C-2+fixation.">A novel screw guiding method with a screw guide template system for posterior C-2 fixation.</a> Neurosurgery Spine. 21 (2), 231-238 (2014).</li><li>Sugawara, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multistep+pedicle+screw+insertion+procedure+with+patient-specific+lamina+fit-and-lock+templates+for+the+thoracic+spine.">Multistep pedicle screw insertion procedure with patient-specific lamina fit-and-lock templates for the thoracic spine.</a> Neurosurgery Spine. 19 (2), 185-190 (2013).</li><li>Li, J., Lin, J. 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The authors have no conflict of interest regarding any drugs, materials, or devices described in this study.

Percutaneous vertebroplasty (PVP) is considered one of the best methods to treat osteoporotic vertebral compression fracture9 due to some distinct advantages: it is minimally invasive; there is less bleeding, and recovery is rapid. Traditional PVP is primarily guided by a C-arm fluoroscope that requires repeated fluoroscopy to determine safe and ideal puncture points, puncture angles and orientations, which increases the intraoperative radiation dosage and the operation time10</s...

As the most common type fracture among all kinds of osteoporotic fractures, osteoporotic vertebral compression fracture (OVCF) is a highly concerning clinical problem nowadays. As current guidelines recommend, percutaneous vertebroplasty is one of the most effective minimally invasive methods to clinically treat osteoporotic vertebral compression fractures1.
Traditionally, surgeons perform percutaneous vertebroplasty guided by a C-arm fluoroscope to treat a vertebral compression fracture to restore the compressed vertebral body and relieve early-stage pain2. Even experienced surgeons make mistakes in confirming suitable puncturing points by simply relying on their personal experience. This operation could cause some puncture-related complications (e.g., cement leakage into surrounding tissues, nerve root injury, intra-spinal hematoma, etc.3,4,5); moreover, almost 50% of patients have local complications from traditional PVP with 95% of complications coming from cement leakage into surrounding tissue or embolization of paravertebral veins6. With the emergence of precision surgery, a 3-D printing guide template has been used in many spinal surgery operations7 because it can enhance the procedural accuracy, decreasing the difficulties and minimizing the operational risks. Here, we apply a 3-D printing guide template into the PVP to make the surgical procedure more precise and to decrease the rate of puncture-related complications. Compared with the traditional method, operations assisted by the 3D printing guide template have 1) increased surgical puncture accuracy, 2) minimized the radiation exposure during the operation, 3) shortened the surgical procedure time, and 4) decreased the probability of puncture-related complications.

<table><tbody><tr><td>X-ray machine</td><td>Company Philips</td><td></td><td>machine</td></tr><tr><td>Magnetic resonance image machine</td><td>Company GE</td><td></td><td>machine</td></tr><tr><td>computer tomography</td><td>Company GE</td><td></td><td>machine</td></tr><tr><td>HORI 3D printing machine</td><td>Company of Beijing Huitianwei Technology co. ltd.</td><td></td><td>machine</td></tr><tr><td>Geomagic Design X</td><td>3D Systems Company</td><td></td><td>software</td></tr><tr><td>Materialise Interactive Medical Image Control System</td><td>Materialise Company</td><td></td><td>software</td></tr><tr><td>VertePort needle</td><td>Stryker Company</td><td></td><td>operation appliance</td></tr><tr><td>Spineplex</td><td>Stryker Company</td><td></td><td>operation appliance</td></tr><tr><td>Percutaneous Cement Delivery System</td><td>Stryker Company</td><td></td><td>operation appliance</td></tr><tr><td>Spirit Level Plus</td><td>IOS App store</td><td></td><td>gradientor</td></tr></tbody></table>

three-dimensional printing guide template assisted percutaneous vertebroplasty (pvp)

Percutaneous vertebroplasty (PVP) is considered an effective treatment for the back pain caused by osteoporotic vertebral compression fracture. The accuracy of PVP mainly depends on the surgeons&#39; experience and multiple fluoroscopes during a traditional procedure. Puncture related complications were reported all over the world. To make the surgical procedure more precise and decrease the rate of puncture-related complications, our team applied a three-dimensional printing guide template to PVP to modify the traditional procedure. This protocol introduces how to model target vertebrae DICOM imaging data into three-dimensions in the software, how to simulate operation in this 3-D model, and how to use all of the surgical data to reconstruct a patient specific template for application. Using this template, surgeons can identify suitable puncture points accurately to improve the accuracy of the operation. The whole protocol includes: 1) diagnosis of the osteoporotic vertebral compression fracture; 2) acquisition of CT imaging of the target vertebra; 3) simulation of the operation in the software; 4) design and fabrication of the 3-D printing guide template; and 5) application of the template into an operation procedure.

Acquisition of CT images and digital modeling were performed in the hospital, while 3-D printing was performed in a 3-D printing company. Thirty minutes were needed to reconstruct the 3-D model from the CT images for the 3-D printing, and the 3-D printing company needed about 6 hours to print 2 guide templates out and send to the hospital.
The pre-operation images of the target vertebra of the patient were shown in <strong class...

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Three-Dimensional Printing Guide Template Assisted Percutaneous Vertebroplasty PVP

Herein, we present a three-dimensional printing guide template for percutaneous vertebraplasty. A patient with a T11 vertebral compression fracture was selected as a case study.

Three-Dimensional Printing Guide Template Assisted Percutaneous Vertebroplasty (PVP)

Percutaneous vertebroplasty (PVP) is considered an effective treatment for the back pain caused by osteoporotic vertebral compression fracture. The ...

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7.5K Views.  Capital Medical University. Herein, we present a three-dimensional printing guide template for percutaneous vertebraplasty. A patient with a T11 vertebral compression fracture was selected as a case study.

Video: Three-Dimensional Printing Guide Template Assisted Percutaneous Vertebroplasty PVP

Cone Beam Intraoperative Computed Tomography-based Image Guidance for Minimally Invasive Transforaminal Interbody Fusion

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. Minimally invasive surgery (MIS) approaches have been applied to this technique with an associated decrease in estimated blood loss (EBL), length of hospital stay, and infection rates, while preserving outcomes with traditional open surgery. Previous MIS TLIF techniques involve significant fluoroscopy that subjects the patient, surgeon, and operating room staff to non-trivial levels of radiation exposure, particularly for complex multi-level procedures. We present a technique that utilizes an intraoperative computed tomography (CT) scan to aid in placement of pedicle screws, followed by traditional fluoroscopy for confirmation of cage placement. Patients are positioned in the standard fashion and a reference arc is placed in the posterior superior iliac spine (PSIS) followed by intraoperative CT scan. This allows for image-guidance-based placement of pedicle screws through a one-inch skin incision on each side. Unlike traditional MIS-TLIF that requires significant fluoroscopic imaging during this stage, the operation can now be performed without any additional radiation exposure to the patient or operating room staff. After completion of the facetectomy and discectomy, final TLIF cage placement is confirmed with fluoroscopy. This technique has the potential to decrease operative time and minimize total radiation exposure.

The purpose of this article is to provide image-guidance for minimally invasive transforaminal interbody fusion.

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. ...

Designing CAD/CAM Surgical Guides for Maxillary Reconstruction Using an In-house Approach

Computer-aided design/computer-assisted manufacturing (CAD/CAM) is now being evaluated as a preparative technique for maxillofacial surgery. Because this technique is expensive and available in only limited areas of the world, we developed a novel CAD/CAM surgical guide using an in-house approach. By using the CAD software, the maxillary resection area and cutting planes and the fibular cutting planes and angles are determined. Once the resection area is decided, the necessary faces are extracted using a Boolean modifier. These superficial faces are united to fit the surface of the bones and thickened to stabilize the solids. Not only the cutting guides for the fibula and maxilla but also the location arrangement of the transferred bone segments is defined by thickening the superficial faces. The CAD design is recorded as .stl files and three-dimensionally (3-D) printed as actual surgical guides. To check the accuracy of the guides, model surgery using 3-D-printed facial and fibular models is performed. These methods may be used to assist surgeons where commercial guides are not available.

Methods for designing a computer-aided design/computer-aided manufacturing (CAD/CAM) surgical guide are shown. Cutting planes are separated, united, and thickened to easily visualize the necessary bone transfer. These designs can be three-dimensional printed and checked for accuracy.

Computer-aided design/computer-assisted manufacturing (CAD/CAM) is now being evaluated as a preparative technique for maxillofacial surgery. Because this ...

Precision Measurements and Parametric Models of Vertebral Endplates

Detailed and comprehensive geometric data of vertebrae endplates is important and necessary to improve the fidelity of finite element models of the spine, design and ameliorate spinal implants, and understand degenerative changes and biomechanics. In this protocol, a high-speed and highly accurate scanner is employed to convert morphology data of endplate surfaces into a digital point cloud. In the software system, the point cloud is further processed and reconstructed into three dimensions. Then, a measurement protocol is performed, involving a 3D coordinate system defined to make each point a 3D coordinate, three sagittal and three frontal surface curves that are symmetrically fitted on the endplate surface, and 11 equidistant points that are selected in each curve. Measurement and spatial analyses are finally performed to obtain geometric data of the endplates. Parametric equations representing the morphology of curves and surfaces are fitted based on the characteristic points. The suggested protocol, which is modular, provides an accurate and reproducible method to obtain geometric data of vertebral endplates and may assist in more sophisticated morphological studies in the future. It will also contribute to designing personalized spinal implants, planning surgical acts, making clinical diagnoses, and developing accurate finite element models.

A reverse engineering system is employed to record and obtain detailed and comprehensive geometry data of vertebral endplates. Parametric models of vertebral endplate are then developed, which are beneficial to designing personalized spinal implants, making clinical diagnoses, and developing accurate finite element models.

Detailed and comprehensive geometric data of vertebrae endplates is important and necessary to improve the fidelity of finite element models of the spine, ...

3D Planning and Printing of Patient Specific Implants for Reconstruction of Bony Defects

We are in the midst of the 3D era in most aspects of life, and especially in medicine. The surgical discipline is one of the major players in the medical field using the constantly developing 3D planning and printing capabilities. Computer-assisted design (CAD) and computer assisted manufacturing (CAM) are used to describe the 3D planning and manufacturing of the product. The planning and manufacturing of 3D surgical guides and reconstruction implants is performed almost exclusively by engineers. As technology advances and software interfaces become more user-friendly, it raises a question regarding the possibility of transferring the planning and manufacturing to the clinician. The reasons for such a shift are clear: the surgeon has the idea of what he wants to design, and he also knows what is feasible and could be used in the operating room. It allows him to be prepared for any scenario/unexpected results during the operation and allows the surgeon to be creative and express his new ideas using the CAD software. The purpose of this method is to provide clinicians with the ability to create their own surgical guides and reconstruction implants. In this manuscript, a detailed protocol will provide a simple method for segmentation using segmentation software and implant planning using a 3D design software. Following the segmentation and stl file production using segmentation software, the clinician could create a simple patient specific reconstruction plate or a more complex plate with a cradle for bone graft positioning. Surgical guides can be created for accurate resection, hole preparation for proper reconstruction plate positioning or for bone graft harvesting and re-contouring. A case of lower jaw reconstruction following plate fracture and nonunion healing of a trauma sustained injury is detailed.

This protocol describes the use of 3D planning and printing for reconstruction of bony defects. We use segmentation tools to create 3D models followed by 3D design software to create patient specific implants for reconstruction purposes concomitant to ablative surgery or as a second stage.

We are in the midst of the 3D era in most aspects of life, and especially in medicine. The surgical discipline is one of the major players in the medical ...

Treatment of Facial Deformities using 3D Planning and Printing of Patient-Specific Implants

Technological advancements in surgical planning and patient-specific implants are constantly evolving. One can either adopt the technology to achieve better results, even in the less experienced hand, or continue without it. As technology develops and becomes more user-friendly, we believe it is time to allow the surgeon the option to plan his/her operations and create his/her own patient-specific surgical guides and fixation plates allowing him full control over the process. We present here a protocol for 3D planning of the operation followed by 3D planning and printing of surgical guides and patient-specific fixation implants. During this process we use two commercial computer-assisted design (CAD) software. We also use a fused deposition&#160;modeling printer for the surgical guides and a selective laser sintering printer for the titanium patient-specific fixation implants. The process includes computed tomography (CT) imaging acquisition, 3D segmentation of the skull and facial bones from the CT, 3D planning of the operations, 3D planning of patient-specific fixation implant according to the final position of the bones, 3D planning of surgical guides for performing an accurate osteotomy and preparing the bone for the fixation plates, and 3D printing of the surgical guides and the patient-specific fixation plates. The advantages of the method include full control over the surgery, planned osteotomies and fixation plates, significant reduction in price, reduction in operation duration, superior performance and highly accurate results. Limitations include the need to master the CAD programs.

As technology develops and becomes more user-friendly, planning of operations and patient-specific surgical guides and fixation plates should be performed by the surgeon. We present a protocol for 3D planning of orthognathic skeletal movements and 3D planning and printing of patient-specific fixation plates and surgical guides.

Technological advancements in surgical planning and patient-specific implants are constantly evolving. One can either adopt the technology to achieve ...

Guided Endodontics: Three-Dimensional Planning and Template-Aided Preparation of Endodontic Access Cavities

Pulp canal obliterations (PCO) are often a consequence of dental trauma, such as luxation injuries. Even though dentin apposition is a sign of vital pulp, pulpitis or apical periodontitis may develop in the long term. Root canal treatment of teeth with severe PCO and pulpal or periapical pathosis is challenging for general practitioners and even for well-equipped endodontic specialists. To ensure detection of the calcified root canal and avoid excessive loss of tooth structure or root perforation, static navigation using templates ("Guided Endodontics") was introduced a few years ago. The general workflow includes three-dimensional imaging using cone-beam computed tomography (CBCT), a digital surface scan, and superimposition of both in a planning software. This is followed by virtual planning of the access cavity and the design of a template that will guide the drill to the desired target point. To do this, a true-to-scale virtual image of the drill must be placed in a way that the tip of the drill reaches the orifice of the calcified root canal. Once the template has been fabricated using computer-aided design and computer-aided manufacturing (CAD/CAM) or a 3D printer, guided preparation of the access cavity can be performed clinically. For research purposes, a postoperative CBCT image can be used to quantify the accuracy of the access cavity performed. This work aims to present the technique of static guided endodontics from imaging to clinical implementation.

Guided endodontics describes a template-aided approach for access cavity preparation. The procedure requires cone-beam computed tomography and a surface scan to produce a template. An incorporated sleeve guides the drill to the target point. This allows the preparation of minimally invasive endodontic access cavities in calcified teeth.

Pulp canal obliterations (PCO) are often a consequence of dental trauma, such as luxation injuries. Even though dentin apposition is a sign of vital pulp, ...

Three-Dimensional Preoperative Virtual Planning in Derotational Proximal Femoral Osteotomy

Anterior knee pain (AKP) is a common pathology among adolescents and adults. Increased femoral anteversion (FAV) has many clinical manifestations, including AKP. There is growing evidence that increased FAV plays a major role in the genesis of AKP. Furthermore, this same evidence suggests that derotational femoral osteotomy is beneficial for these patients, as good clinical results have been reported. However, this type of surgery is not widely used among orthopedic surgeons.
The first step in attracting orthopedic surgeons to the field of rotational osteotomy is to give them a methodology that simplifies preoperative surgical planning and allows for the previsualization of the results of surgical interventions on computers. To that end, our working group uses 3D technology. The imaging dataset used for surgical planning is based on a CT scan of the patient. This 3D method is open access (OA), meaning it is accessible to any orthopedic surgeon at no economic cost. Furthermore, it not only allows for the quantification of femoral torsion but also for carrying out virtual surgical planning. Interestingly, this 3D technology shows that the magnitude of the intertrochanteric rotational femoral osteotomy does not present a 1:1 relationship with the correction of the deformity. Additionally, this technology allows for the adjustment of the osteotomy so that the relationship between the magnitude of the osteotomy and the correction of the deformity is 1:1. This paper outlines this 3D protocol.

This work presents a detailed surgical planning protocol using 3D technology with free open-source software. This protocol can be used to correctly quantify femoral anteversion and simulate derotational proximal femoral osteotomy for the treatment of anterior knee pain.

Anterior knee pain (AKP) is a common pathology among adolescents and adults. Increased femoral anteversion (FAV) has many clinical manifestations, ...

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.

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.

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

Biomechanical Analysis of Adjacent Segments after Spinal Fusion Surgery Using a Geometrically Parametric Patient-Specific Finite Element Model

This study aimed to perform a mechanical analysis of adjacent segments after spinal fusion surgery using a geometrically parametric patient-specific finite element model to elucidate the mechanism of adjacent segment degeneration (ASD), thereby providing theoretical evidence for early disease prevention. Fourteen parameters based on patient-specific spinal geometry were extracted from a patient's preoperative computed tomography (CT) scan, and the relative positions of each spinal segment were determined using the image match method. A preoperative patient-specific model of the spine was established through the above method. The postoperative model after L4-L5 posterior lumbar interbody fusion (PLIF) surgery was constructed using the same method except that the lamina and intervertebral disc were removed, and a cage, 4 pedicle screws, and 2 connecting rods were inserted. Range of motion (ROM) and stress changes were determined by comparing the values of each anatomical structure between the preoperative and postoperative models. The overall ROM of the lumbar spine decreased after fusion, while the ROM, stress in the facet joints, and stress in the intervertebral disc of adjacent segments all increased. An analysis of the stress distribution in the annulus fibrosus, nucleus pulposus, and facet joints also showed that not only was the maximum stress in these tissues elevated, but the areas of moderate-to-high stress were also expanded. During torsion, the stress in the facet joints and annulus fibrosus of the proximal adjacent segment (L3-L4) increased to a larger extent than that in the distal adjacent segment (L5-S1). While fusion surgery causes an overall restriction of motion in the lumbar spine, it also causes more load sharing by the adjacent segments to compensate for the fused segment, thus increasing the risk of ASD. The proximal adjacent segment is more prone to degeneration than the distal adjacent segment after spinal fusion due to the significant increase in stress.

Here, we used a patient-specific finite element model to analyze the mechanical changes in adjacent segments after spinal fusion surgery. The results showed that fusion surgery reduced the overall motion of the lumbar spine but increased the load on and stress in adjacent segments, especially the proximal segment.

This study aimed to perform a mechanical analysis of adjacent segments after spinal fusion surgery using a geometrically parametric patient-specific ...

Enhancing Pedicle Puncture Precision with 3D Modeling and a Nine-Grid Method

Nine-Grid Area Division Method: A New Ideal Bone Puncture Region for Percutaneous Vertebroplasty in Lumbar Spine

Percutaneous vertebroplasty (PVP) is widely recognized as an efficacious intervention for alleviating low back pain resulting from osteoporotic vertebral compression fractures. The ideal bone puncture point is conventionally situated at the projection "left 10 points, right 2 points" of the pedicle in the lumbar spine. Determining the optimal bone puncture point represents a critical and complex challenge. The accuracy of percutaneous vertebroplasty (PVP) is primarily influenced by the proficiency of the operating surgeons and the utilization of multiple fluoroscopes during the conventional procedure. Incidences of puncture-related complications have been documented globally. In an effort to enhance the precision of the surgical technique and reduce the occurrence of puncture-related complications, our team applied the "Nine-grid Area Division Method" for PVP in the lumbar spine to modify the traditional procedure. There is potential to decrease the number of puncture times, the radiation exposure dosage, and the duration of surgical procedures.
This protocol introduces the definition of the "Nine-grid Area Division Method" and describes the process of modeling target vertebrae DICOM imaging data within medical imaging processing software, simulating operations within a 3-D model, refining the 3-D model using reverse engineering production software, reconstructing the vertebral engineering model within 3-D modeling design software, and utilizing surgical data to determine safe entry regions for pedicle projection. By employing this methodology, surgeons can effectively identify appropriate puncture points with precision and ease, thereby reducing the intricacies associated with puncturing and enhancing the overall accuracy of surgical procedures.

Author Spotlight: Improving Percutaneous Vertebroplasty Surgical Accuracy and Efficiency Through Advanced Puncture Techniques

Herein, we present a "Nine-grid Area Division Method" for percutaneous vertebroplasty. A patient with an L1 vertebral compression fracture was selected as a case study.

Percutaneous vertebroplasty (PVP) is widely recognized as an efficacious intervention for alleviating low back pain resulting from osteoporotic vertebral ...