Name: digital hybrid model preparation for virtual planning of reconstructive dentoalveolar surgical procedures
Uploaded: 2021-08-05T14:15:00
Description: Watch this Scientific Journal Video about Digital Hybrid Model Preparation for Virtual Planning of Reconstructive Dentoalveolar Surgical Procedures at JoVE.com

This study was conducted in complete accordance with the Declaration of Helsinki. Before manuscript preparation, written informed consent was provided and signed by the patient. The patient granted permission for data usage for the demonstration of the protocol.
1. Radiographic image processing
<ol>
	<li>Load DICOM files into the software
	<ol>
		<li>Download the newest version of the medical imaging software and open it. 
		NOTE: After opening the software, the home screen will appear....

<ol>
	<li>Jacobs, R., Salmon, B., Codari, M., Hassan, B., Bornstein, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cone+beam+computed+tomography+in+implant+dentistry:+recommendations+for+clinical+use.">Cone beam computed tomography in implant dentistry: recommendations for clinical use.</a> BMC Oral Health. 18 (1), 88 (2018).</li><li>Mangano, F., Gandolfi, A., Luongo, G., Logozzo, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intraoral+scanners+in+dentistry:+a+review+of+the+current+literature.">Intraoral scanners in dentistry: a review of the current literature.</a> BMC Oral Health. 17 (1), 149 (2017).</li><li>Pauwels, R., Araki, K., Siewerdsen, J. H., Thongvigitmanee, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technical+aspects+of+dental+CBCT:+state+of+the+art.">Technical aspects of dental CBCT: state of the art.</a> Dentomaxillofacial Radiology. 44 (1), 20140224 (2015).</li><li>Queiroz, P. M., Santaella, G. M., Groppo, F. C., Freitas, D. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal+artifact+production+and+reduction+in+CBCT+with+different+numbers+of+basis+images.">Metal artifact production and reduction in CBCT with different numbers of basis images.</a> Imaging Science in Dentistry. 48 (1), 41-44 (2018).</li><li>Scarfe, W. C., Azevedo, B., Pinheiro, L. R., Priaminiarti, M., Sales, M. A. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+emerging+role+of+maxillofacial+radiology+in+the+diagnosis+and+management+of+patients+with+complex+periodontitis.">The emerging role of maxillofacial radiology in the diagnosis and management of patients with complex periodontitis.</a> Periodontology 2000. 74 (1), 116-139 (2017).</li><li>Fedorov, A., 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=3D+Slicer+as+an+image+computing+platform+for+the+Quantitative+Imaging+Network.">3D Slicer as an image computing platform for the Quantitative Imaging Network.</a> Magnetic Resonance Imaging. 30 (9), 1323-1341 (2012).</li><li>Palkovics, D., Mangano, F. G., Nagy, K., Windisch, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+three-dimensional+visualization+of+intrabony+periodontal+defects+for+regenerative+surgical+treatment+planning.">Digital three-dimensional visualization of intrabony periodontal defects for regenerative surgical treatment planning.</a> BMC Oral Health. 20 (1), 351 (2020).</li><li>Papadiochou, S., Pissiotis, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Marginal+adaptation+and+CAD-CAM+technology:+A+systematic+review+of+restorative+material+and+fabrication+techniques.">Marginal adaptation and CAD-CAM technology: A systematic review of restorative material and fabrication techniques.</a> Journal of Prosthetic Dentisty. 119 (4), 545-551 (2018).</li><li>Xia, J. J., 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=Algorithm+for+planning+a+double-jaw+orthognathic+surgery+using+a+computer-aided+surgical+simulation+(CASS)+protocol.+Part+1:+planning+sequence.">Algorithm for planning a double-jaw orthognathic surgery using a computer-aided surgical simulation (CASS) protocol. Part 1: planning sequence.</a> International Journal of Oral Maxillofacial Surgery. 44 (12), 1431-1440 (2015).</li><li>Xia, J. J., 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=Algorithm+for+planning+a+double-jaw+orthognathic+surgery+using+a+computer-aided+surgical+simulation+(CASS)+protocol.+Part+2:+three-dimensional+cephalometry.">Algorithm for planning a double-jaw orthognathic surgery using a computer-aided surgical simulation (CASS) protocol. Part 2: three-dimensional cephalometry.</a> International Journal of Oral Maxillofacial Surgery. 44 (12), 1441-1450 (2015).</li><li>Lee, C. Y., Ganz, S. D., Wong, N., Suzuki, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+cone+beam+computed+tomography+and+a+laser+intraoral+scanner+in+virtual+dental+implant+surgery:+part+1.">Use of cone beam computed tomography and a laser intraoral scanner in virtual dental implant surgery: part 1.</a> Implant Dentistry. 21 (4), 265-271 (2012).</li><li>Ganz, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+imaging+and+guided+surgery+for+dental+implants.">Three-dimensional imaging and guided surgery for dental implants.</a> Dental Clinics of North America. 59 (2), 265-290 (2015).</li><li>G&#252;th, J. F., Kauling, A. E. C., Schweiger, J., K&#252;hnisch, J., Stimmelmayr, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Virtual+simulation+of+periodontal+surgery+including+presurgical+CAD/CAM+fabrication+of+tooth-colored+removable+splints+on+the+basis+of+CBCT+Data:+A+case+report.">Virtual simulation of periodontal surgery including presurgical CAD/CAM fabrication of tooth-colored removable splints on the basis of CBCT Data: A case report.</a> The International Journal of Periodontics &amp; Restorative Dentistry. 37 (6), 310-320 (2017).</li><li>Pauwels, R., 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=Effective+radiation+dose+and+eye+lens+dose+in+dental+cone+beam+CT:+effect+of+field+of+view+and+angle+of+rotation.">Effective radiation dose and eye lens dose in dental cone beam CT: effect of field of view and angle of rotation.</a> The British Journal of Radiology. 87 (1042), 20130654 (2014).</li><li>Li, Q., Chen, K., Han, L., Zhuang, Y., Li, J., Lin, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automatic+tooth+roots+segmentation+of+cone+beam+computed+tomography+image+sequences+using+U-net+and+RNN.">Automatic tooth roots segmentation of cone beam computed tomography image sequences using U-net and RNN.</a> Journal of X-ray Science and Technology. 28 (5), 905-922 (2020).</li><li>Lahoud, P., 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=Artificial+intelligence+for+fast+and+accurate+3D+tooth+segmentation+on+CBCT.">Artificial intelligence for fast and accurate 3D tooth segmentation on CBCT.</a> Journal of Endodontics. 47 (5), 827-835 (2021).</li><li>Blume, O., Donkiewicz, P., Back, M., Born, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bilateral+maxillary+augmentation+using+CAD/CAM+manufactured+allogenic+bone+blocks+for+restoration+of+congenitally+missing+teeth:+A+case+report.">Bilateral maxillary augmentation using CAD/CAM manufactured allogenic bone blocks for restoration of congenitally missing teeth: A case report.</a> Journal of Esthetic and Restorative Dentistry. 31 (3), 171-178 (2019).</li><li>Hartmann, A., Seiler, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimizing+risk+of+customized+titanium+mesh+exposures+-+a+retrospective+analysis.">Minimizing risk of customized titanium mesh exposures - a retrospective analysis.</a> BMC Oral Health. 20 (1), 36 (2020).</li><li>Varga, E., 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=Guidance+means+accuracy:+A+randomized+clinical+trial+on+freehand+versus+guided+dental+implantation.">Guidance means accuracy: A randomized clinical trial on freehand versus guided dental implantation.</a> Clinical Oral Implants Research. 31 (5), 417-430 (2020).</li></ol>

With the presented protocol, periodontal and alveolar defect morphologies can be visualized in three dimensions (3D), providing a more accurate depiction of the clinical situation than can be achieved by 2D diagnostic methods and 3D models generated with thresholding algorithms. The protocol can be divided into three major phases: (1) semi-automatic segmentation of CBCT datasets, (2) spatial registration of CBCT and IOS, and (3) free-form surface modeling. Technically, segmentation can be performed on any three-dimension...

Technological advancements in dentistry have enabled computer-aided treatment planning and simulation of surgical procedures and prosthetic rehabilitation. Two essential methods for 3D data acquisition in digital dentistry are: (1) cone-beam computed tomography (CBCT)1 and (2) intraoral optical scanning (IOS)2. Digital information of all relevant anatomical structures (alveolar bone, teeth, soft tissues) can be acquired using these tools to plan reconstructive dentoalveolar surgical procedures.
Cone-beam technology was first introduced in 1996 by an Italian research group. Delivering significantly lower radiation dose and higher resolution (compared to conventional computed tomography), CBCT has quickly become the most frequently used 3D imaging modality in dentistry and oral surgery3. CBCT is often used to plan different surgical procedures (e.g., periodontal regenerative surgery, alveolar ridge augmentation, dental implant placement, orthognathic surgery)1. CBCT datasets are viewed and can be processed in radiographic imaging software that provides 2D images, and 3D renders-however, most imaging software use threshold-based algorithms for 3D image reconstruction. Thresholding methods set the upper and lower bounds of a voxel grey value interval. Voxels that fall in between these bounds will be rendered in 3D. This method allows speedy model acquisition; however, since the algorithm cannot differentiate anatomical structures from metal artifacts and scattering, the 3D renders are highly inaccurate and have very little diagnostic value4,5. For the reasons mentioned above, many fields within dentistry still rely on conventional 2D radiographs (intraoral radiographs, panoramic X-ray) or the 2D images of CBCT datasets5. Our research group presented a semi-automatic image segmentation method in a recently published article, using open-source radiographic image processing software6 wherein anatomically based 3D reconstruction of CBCT datasets is performed7. With the help of this method, anatomical structures were differentiated from metal artifacts, and, more importantly, alveolar bone and teeth could be separated. Therefore, a realistic virtual model of hard tissues could be acquired. 3D models were used to evaluate intrabony periodontal defects and for treatment planning before regenerative periodontal surgeries.
Intraoral optical surface scanners provide digital information on clinical conditions (clinical crown of the teeth and soft tissues). The original intended purpose of these devices was to directly acquire digital models of patients for the planning and fabrication of dental prostheses with computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies8. However, due to the wide range of applications, their use was quickly implemented in other fields of dentistry. Maxillo-facial surgeons combine IOS and CBCT into a hybrid setup that can be utilized for virtual osteotomy and digital planning of orthognathic surgeries9,10. Dental implantology is probably the field that uses digital planning and guided execution most commonly. Navigated surgery eliminates most complications related to implant mispositioning. The combination of CBCT datasets and stereolithography (.stl) files of IOS is routinely used to plan the guided implant placement and the fabrication of static implant drilling guides11,12. Intraoral scans superimposed over CBCT datasets have also been used to prepare esthetic crown lengthening13; however, soft tissues were superimposed only over CBCT datasets reconstructed with thresholding algorithms. Yet, to perform accurate 3D virtual planning of regenerative-reconstructive surgical interventions and dental implant placement, realistic 3D hybrid models of patients must be composed of CBCT and IOS data.
Hence, this article aims to present a step-by-step method to acquire realistic hybrid digital models for virtual surgical planning before reconstructive dentoalveolar surgical interventions.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3DSlicer</td>
			<td>3DSlicer (The software was first developed at Queen&#8217;s University Canada and since it is open source it is constantly developed by it&#8217;s community)</td>
			<td>4.13.0-2021-03-19</td>
			<td>Open source radiographic image processing software platform. Software is primarily intended for general medicine, however the wide range of segmentation an modelling tools allow it&#8217;s use for dental purposes as well</td>
		</tr>
		<tr>
			<td>Meshmixer</td>
			<td>Autodesk Inc.</td>
			<td>3.5</td>
			<td>Open source free form surface modelling software developed for prototype development and basic 3D sculpting. However, due to the usefulness of tools for dental purpose, not just 3D models, but even static guides for navigated surgery can be designed.</td>
		</tr>
	</tbody>
</table>

digital hybrid model preparation for virtual planning of reconstructive dentoalveolar surgical procedures

Virtual, hybrid three-dimensional (3D) model acquisition is presented in this article, utilizing the sequence of radiographic image segmentation, spatial registration, and free-form surface modeling. Firstly cone-beam computed tomography datasets were reconstructed with a semi-automatic segmentation method. Alveolar bone and teeth are separated into different segments, allowing 3D morphology, and localization of periodontal intrabony defects to be assessed. The severity, extent, and morphology of acute and chronic alveolar ridge defects are validated concerning adjacent teeth. On virtual complex tissue models, positions of dental implants can be planned in 3D. Utilizing spatial registration of IOS and CBCT data and subsequent free-form surface modeling, realistic 3D hybrid models can be acquired, visualizing alveolar bone, teeth, and soft tissues. With the superimposition of IOS and CBCT soft tissue, thickness above the edentulous ridge can be assessed about the underlying bone dimensions; therefore, flap design and surgical flap management can be determined, and occasional complications may be avoided.

Virtual allowing three-dimensional (3D) models can be generated using radiographic image segmentation, spatial registration, and free-form modeling. The models digitally depict the clinical situation, making three-dimensional planning of various surgical interventions possible. With separate segmentation of bone and teeth, the boundary between the two anatomical structures is visible, 3D morphology and localization of periodontal intrabony defects are to be assessed. The severity, extent, and morphology of acute and chro...

Watch this Scientific Journal Video about Digital Hybrid Model Preparation for Virtual Planning of Reconstructive Dentoalveolar Surgical Procedures at JoVE.com

Digital Hybrid Model Preparation for Virtual Planning of Reconstructive Dentoalveolar Surgical Procedures

A workflow for creating three-dimensional (3D) virtual hybrid models has been designed based on cone-beam computed tomography dataset and intraoral optical scans utilizing radiographic image segmentation methods and free-form surface modeling. Digital models are used for the virtual planning of reconstructive dentoalveolar surgical procedures.

Virtual, hybrid three-dimensional (3D) model acquisition is presented in this article, utilizing the sequence of radiographic image segmentation, spatial ...

Realistic virtual models can show periodontal and alveolar rich defects in three dimensions. Therefore, they can aid the surgical treatment process and provide a deeper understanding on postoperative healing mechanisms. Compared to previous and existing methods, the current approach displays each anatomical structure independently.Therefore, these 3D virtual models represent the real clinical scenario realistically. This method helps to overcome the limitations of traditional diagnostic processes. For example, dental implant placement can be planned on 3D models instead of plenary images of the CBCT scans.The current protocol can be applied in other fields of dentistry, such as endodontic microsurgery, orthotic surgery, and reconstructive surgery following facial tumor resection. Begin with the process segmentation by accessing the segment editor module, select the previously created cropped volume as the master volume of the active segmentation. Use Add to add and Remove to remove segments.Then rename the segments according to the anatomical structure they will represent. Start the segmentation of the alveolar bone by opening the list of effects and selecting Level Tracing, a semi-automatic tool that outlines the region where pixels have the same background value as the selected pixel. Next, drag the mouse to the perimeter of the bone on one of the 2D views, and press the left mouse button to generate the segment on the selected slice of the dataset.Then use the Paint and Erase Hand Tools to modify the segment and correct mistakes. Outline teeth and implants using the Erase tool and delete all highlighted pixels representing them. Repeat the process on every fifth slice of the dataset in the selected orientation.Upon completing the outlining process, compute the missing segments by selecting Fill Between slices from the Effects list and click Initialize to activate contour interpolation. If the results are satisfactory, click Apply. Then scroll through the dataset upon completion to check and correct occasional mistakes.Use the Smoothing effect by selecting Median as the smoothing method. Then set the kernel size to five by five by five pixels by adjusting the millimeter value in the bracket and clicking Apply to make segment boundaries smoother by removing protrusions. Once the segmentation of alveolar bone is completed, repeat the same steps for the segmentation of teeth.Select segmentation from the dropdown bar to add the STL file of the intraoral scan as segmentation. Move the cursor over the module and from the sidebar, select the Fiducial Registration Wizard. From the dropdown menus in both, the From Fiducials and To Fiducial sections, choose Create New MarkupsFiducial.In the From section next to the dropdown bar, use the Place a Markup Point icon to place marker points on well-defined anatomical landmarks on the intraoral optical scanning or IOS. Markup points will be numbered in order of placement. Place markers in the same position to create the To list.And in the same order on the cone-beam computed tomography or CBCT dataset, markup points with the same number must represent the same anatomical landmark. After the To lists are ready, access the dropdown menu in the Registration Result Transform section of the sidebar and select Create New Linear Transform to create a transformation. Access the transforms module and select the previously created transformation as the act of transform.In the Apply Transform section, move the IOS segmentation and the From Markups list from the Transformable box to the Transformed box. This step will help to superpose the IOS over the CBCT dataset. Open the computer-aided design or CAD software, and click Import on the home screen.Then select the STL models previously exported from the DICOM image processing software. Go to Sculpt in the menu bar. And from the brush inventory, select the Adaptive Reduce to refine imported models.In the sidebar, click on the Select tab and choose Brush as the selection tool. Then use Unwrap Brush mode and adjust the size of the brush. Using the brush, select the crown of each tooth until the marginal gingiva is on the IOS.From Modify tab, select Smooth Boundary and click Apply if the results are satisfactory. Go to Select and choose Edit and Separate to create individual object from the selected area. Next, go to Analysis in the menu bar and select Inspect.Select Flat Fill as the whole fill mode, and click Auto Repair All to create closed models from the IOS model and the separated teeth models. In the Sculpt menu, choose Shrink Smooth Brush and smooth out the edges of the filled hole. Use the Shrink Smooth Brush on the segmented tooth model until teeth are completely covered by the tooth crowns separated from the IOS.In the object browser, select both the separated crown and the segmented model of the same tooth. In the popup sidebar, select Boolean Union and click Accept. Use Shrink Smooth to smooth the transition.Select both bone and soft tissue models in the object browser, and then opt for the Boolean difference. Using the same process and smooth transitions as described, subtract teeth from the soft tissue model to represent the clinical situation realistically. Color the surfaces of the models by selecting Sculpt from the sidebar, and then switching the little slider from Volume to Surface.From the brush inventory, go to Paint Vertex and use the color wheel in the Color section to select the desired color. Color the surface of each model. The representative analysis shows the outlining of the pixeled region of interest with the same background value with a yellow line.The semi-automatic segmentation tool of level tracing was used in sagittal orientation, followed by subsequent manual segmentation. The results of the semi-automatic segmentation were refined with the help of manual tools, such as Paint and Erase. Finished segmentation was observed in axial, sagittal, and coronal view, and the 3D model was generated automatically from the segments created previously.Super imposition of IOS and subsequent CAD modeling allowed for viewing the clinical situation in three dimensions. Level tracing is an efficient and smart edge detection tool. However, due to artifacts and scatter, the created segments may still need to be modified manually.This process is relatively new. However, the results so far are very promising. 3D models could have a huge potential in the planning, execution, and evolution of surgical procedures in dental surgery and periodontology.

digital-hybrid-model-preparation-for-virtual-planning-reconstructive

Research

JoVE Journal

Medicine

Surgical Procedures for a Rat Model of Partial Orthotopic Liver Transplantation with Hepatic Arterial Reconstruction

Orthotopic liver transplantation (OLT) in rats using a whole or partial graft is an indispensable experimental model for transplantation research, such as studies on graft preservation and ischemia-reperfusion injury 1,2, immunological responses 3,4, hemodynamics 5,6, and small-for-size syndrome 7. The rat OLT is among the most difficult animal models in experimental surgery and demands advanced microsurgical skills that take a long time to learn. Consequently, the use of this model has been limited. Since the reliability and reproducibility of results are key components of the experiments in which such complex animal models are used, it is essential for surgeons who are involved in rat OLT to be trained in well-standardized and sophisticated procedures for this model.
While various techniques and modifications of OLT in rats have been reported 8 since the first model was described by Lee et al. 9 in 1973, the elimination of the hepatic arterial reconstruction 10 and the introduction of the cuff anastomosis technique by Kamada et al. 11 were a major advancement in this model, because they simplified the reconstruction procedures to a great degree. In the model by Kamada et al., the hepatic rearterialization was also eliminated. Since rats could survive without hepatic arterial flow after liver transplantation, there was considerable controversy over the value of hepatic arterialization. However, the physiological superiority of the arterialized model has been increasingly acknowledged, especially in terms of preserving the bile duct system 8,12 and the liver integrity 8,13,14.
In this article, we present detailed surgical procedures for a rat model of OLT with hepatic arterial reconstruction using a 50% partial graft after ex vivo liver resection. The reconstruction procedures for each vessel and the bile duct are performed by the following methods: a 7-0 polypropylene continuous suture for the supra- and infrahepatic vena cava; a cuff technique for the portal vein; and a stent technique for the hepatic artery and the bile duct.

Orthotopic liver transplantation in rats is an indispensable experimental model for biomedical research. Here we present our surgical procedures for orthotopic rat liver transplantation with hepatic arterial reconstruction using a 50% partial graft.

Orthotopic liver transplantation (OLT) in rats using a whole or partial graft is an indispensable experimental model for transplantation research, such as ...

Surgical Fixation of Sternal Fractures: Preoperative Planning and a Safe Surgical Technique Using Locked Titanium Plates and Depth Limited Drilling

Different ways to stabilize a sternal fracture are described in literature. Respecting different mechanisms of trauma such as the direct impact to the anterior chest wall or the flexion-compression injury of the trunk, there is a need to retain each sternal fragment in the correct position while neutralizing shearing forces to the sternum. Anterior sternal plating provides the best stability and is therefore increasingly used in most cases. However, many surgeons are reluctant to perform sternal osteosynthesis due to possible complications such as difficulties in preoperative planning, severe injuries to mediastinal organs, or failure of the performed method.
This manuscript describes one possible safe way to stabilize different types of sternal fractures in a step by step guidance for anterior sternal plating using low profile locking titanium plates. Before surgical treatment, a detailed survey of the patient and a three dimensional reconstructed computed tomography is taken out to get detailed information of the fracture&#8217;s morphology. The surgical approach is usually a midline incision. Its position can be described by measuring the distance from upper sternal edge to the fracture and its length can be approximated by the summation of 60 mm for the basis incision, the thickness of presternal soft tissue and the greatest distance between the fragments in case of multiple fractures.
Performing subperiosteal dissection along the sternum while reducing the fracture, using depth limited drilling, and fixing the plates prevents injuries to mediastinal organs and vessels.
Transverse fractures and oblique fractures at the corpus sterni are plated longitudinally, whereas oblique fractures of manubrium, sternocostal separation and any longitudinally fracture needs to be stabilized by a transverse plate from rib to sternum to rib. Usually the high convenience of a patient is seen during follow up as well as a precise reconstruction of the sternal morphology.

Here we present a method to stabilize sternal fractures by using locked titanium plates in a low profile design. Performing subperiosteal dissection along the sternum while reducing the fracture, using depth limited drilling, and fixing the plates provides a safe surgical way.

Different ways to stabilize a sternal fracture are described in literature. Respecting different mechanisms of trauma such as the direct impact to the ...

Improvement of a Closed Chest Porcine Myocardial Infarction Model by Standardization of Tissue and Blood Sampling Procedures

Myocardial ischemia reperfusion (I/R) injury contributes to almost half of the necrotic area after myocardial infarction. To date there is no approved drug to prevent or reduce myocardial I/R injury. The study and understanding of the pathophysiological mechanisms of myocardial I/R injury is essential to develop successful treatments. Large animal experiments are an important step in translational methods. The porcine model of acute myocardial infarction has been established and described by ourselves and others. We aimed to further improve the value of the model by focusing in detail on the sampling techniques for use in future experiments. Furthermore, we emphasize small but important steps that can affect the quality of the final results. To mimic the clinical situation of myocardial I/R injury, a percutaneous coronary intervention (PCI) catheter was inserted into the left anterior descending coronary artery (LAD) of an anesthetized pig. &#176;&#176;&#176;This model mimics acute myocardial infarction and PCI treatment in humans with the possibility of accurately determining the area at risk as well as the necrotic- and viable ischemic tissue. Here the model was used to investigate the effect of a bicyclic peptide inhibitor of FXIIa. The model can also be modified to allow longer reperfusion times to study later effects of myocardial infarction.

Here we demonstrate a protocol to standardize sampling procedures of an established porcine model of acute myocardial infarction in order to increase its translational value in the understanding of the pathophysiology of myocardial ischemia/reperfusion injury and to test novel drug candidates.

Myocardial ischemia reperfusion (I/R) injury contributes to almost half of the necrotic area after myocardial infarction. To date there is no approved ...

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 ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

A Pre-clinical Rat Model for the Study of Ischemia-reperfusion Injury in Reconstructive Microsurgery

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many areas of biomedical research due to its cost-effectiveness and its translation to humans. This protocol describes a method to create a preclinical free skin flap model in rats with ischemia-reperfusion injury. The described 3 cm x 6 cm rat free skin flap model is easily obtained after the placement of several vascular ligatures and the section of the vascular pedicle. Then, 8 h after the ischemic insult and completion of the microsurgical anastomosis, the free skin flap develops the tissue damage. These ischemia-reperfusion injury-related damages can be studied in this model, making it a suitable model for evaluating therapeutic agents to address this pathophysiological process. Furthermore, two main monitoring techniques are described in the protocol for the assessment of this animal model: transit-time ultrasound technology and laser speckle contrast analysis.

Here, we describe a pre-clinical animal model for studying the pathophysiology of ischemia-reperfusion injury in reconstructive microsurgery. This free skin flap model based on the superficial caudal epigastric vessels in the rat may also allow for the evaluation of different therapies and compounds to counteract ischemia-reperfusion injury-related damage.

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many ...

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 Reconstruction for the Diagnosis and Treatment of Pulmonary Nodules

A 3D Digital Model for the Diagnosis and Treatment of Pulmonary Nodules

The three-dimensional (3D) reconstruction of pulmonary nodules using medical images has introduced new technical approaches for diagnosing and treating pulmonary nodules, and these approaches are progressively being acknowledged and adopted by physicians and patients. Nonetheless, constructing a relatively universal 3D digital model of pulmonary nodules for diagnosis and treatment is challenging due to device differences, shooting times, and nodule types. The objective of this study is to propose a new 3D digital model of pulmonary nodules that serves as a bridge between physicians and patients and is also a cutting-edge tool for pre-diagnosis and prognostic evaluation. Many AI-driven pulmonary nodule detection and recognition methods employ deep learning techniques to capture the radiological features of pulmonary nodules, and these methods can achieve a good area under-the-curve (AUC) performance. However, false positives and false negatives remain a challenge for radiologists and clinicians. The interpretation and expression of features from the perspective of pulmonary nodule classification and examination are still unsatisfactory. In this study, a method of continuous 3D reconstruction of the whole lung in horizontal and coronal positions is proposed by combining existing medical image processing technologies. Compared with other applicable methods, this method allows users to rapidly locate pulmonary nodules and identify their fundamental properties while also observing pulmonary nodules from multiple perspectives, thereby providing a more effective clinical tool for diagnosing and treating pulmonary nodules.

Author Spotlight: A 3D Digital Model for the Diagnosis and Treatment of Pulmonary Nodules  

The objective of this study is to develop a novel 3D digital model of pulmonary nodules that serves as a communication bridge between physicians and patients and is also a cutting-edge tool for pre-diagnosis and prognostic evaluation.

The three-dimensional (3D) reconstruction of pulmonary nodules using medical images has introduced new technical approaches for diagnosing and treating ...

Digital Model for Horizontal 3D Reconstruction of Pulmonary Nodules

To reconstruct the three-dimensional digital model of the pulmonary nodules, implement the Three-Dimensional Lung Horizon Function in the MATLAB workspace. Then open the Graphical User Interface, or GUI, to check the horizontal three-dimensional model. Drag the scroll bar on the GUI with the mouse to observe the continuous three-dimensional lung structure, allowing for the clear visualization of various types of pulmonary nodules and their relative spatial relationships with the lung tissue.Use the Zoom function to observe the local features of the lesions and relevant three-dimensional structural output pictures. To measure the size of the nodules, use the Mark Pixel Coordinates button to calculate the distance between two points. The default color bar, jet colormap, displays values from low to high in a blue to red range.To reset the GUI, right click the color bar and select the standard gray colormap. If the filter window is not satisfactory, use the left mouse button to adjust the window level by dragging up and down in the middle of the figure. Drag left and right to adjust the window width to display the accurate filtering range on the color bar.The continuous three-dimensional reconstruction resulted in the axial view of the pulmonary nodules and the relationship between the nodules and the surrounding lung tissue.