This study was supported by the health Committee of Sichuan Province (Grant No.20PJ061), the National Natural Science Foundation of China (Grant No.32101188), and the General Project of Science and Technology Department of Sichuan Province (Grant No. 2021YFS0102), China.

This study did not need approval to perform or any sort of consent from the patients to use and publish their data, because all the data and information in this study and video were anonymized.
1. Collection of image data
<ol>
	<li>Scan the patient&#39;s thyroid by enhanced computerized tomography (CT) to obtain the image data in DICOM format. Ensure that this process is done within 1 week before the operation and control the slice thickness so that it is &#8804;1 mm.</li>
</ol>
2. Processing of DICOM data
<ol>
	<li>Import the scanned patient image data into the software (see Table of Materials) and set the appropriate threshold according to the difference in gray value between the thyroid gland and surrounding tissues or organs. As different gray values are reflections of differences in the density of different areas of the human body, set the grayscale threshold (unit: hu; on the software) to 226-1,500 to present the bone image; set the threshold to -200-226 to show the thyroid gland image. Let the software automatically identify the boxed area, or manually outline the boundary of the target area if the recognition is not satisfactory. 
	NOTE: Mimics automatically select the thyroid region and use the 3D region growth technology to segment the image and calculate the 3D reconstruction. At the same time, the 3D image is optimized to reduce the roughness and the sense of steps to obtain a natural, smooth, and authentic 3D digital visualization model, which enables a more straightforward observation of the 3D model for surgeons.</li>
	<li>Generate STL files from the reconstructed data model. Choose the reconstructed model in the software, click Export in the file dock, and choose STL as the exporting file format. Finally, generate the STL files successfully.</li>
</ol>
3. Medical-engineering interaction
<ol>
	<li>Send the reconstructed 3D model preview to the doctors, who will confirm the applied requirements and anatomical structure of the 3D model and give feedback to the modeling engineer if a modification is needed. After receiving confirmations from the doctors, proceed to the production preparation stage.</li>
</ol>
4. 3D printing (Supplemental File 1)
<ol>
	<li>Transfer the STL file data to the colorful material 3D printer and complete the parameter presets (such as printing mode, slice stroke thickness, support method, and model coloring) through the supporting 3D printing slicing software.
	<ol>
		<li>Select the printing model according to the type of finished products (color printing models usually use White Jet Process technology, while photosensitive resin usually uses Digital Light Procession).</li>
		<li>Select slice stroke thickness parameter according to the thickness of the products (here, from 24 &#181;m to 36 &#181;m).</li>
		<li>Choose the support method according to the fineness of the printing model: Overall support (better protection and less damage to fine details) or Partial support (which saves materials).</li>
		<li>Select model coloring using the color palette function on the printer. Unify the arteries with red color 255 and the veins with blue color 255. 
		NOTE: As other parts such as the tumor lesion are not strictly standard, surgeons can select a color according to their needs or preference.</li>
	</ol>
	</li>
	<li>Fill in hard light curing resin in the 3D printer (see Supplemental Table S1), debug the printing platform, and print using White Jet Process technology. After printing, take out the preliminary printed thyroid model. 
	&#8203;NOTE: The White Jet Process technology is based on the principle of inkjet printing, where a thin layer of photosensitive resin is printed out in one jet and then irradiated with a specific wavelength of UV light, causing a rapid polymerization reaction and curing of the photosensitive resin. This process is completed layer by layer until the print is complete.</li>
</ol>
5. Post-treatment
<ol>
	<li>Subtract the support structure of the preliminary printed thyroid model. Grind, varnish, and cure the semi-manufactured product to obtain an individualized 1:1 isometric 3D-printed thyroid model.
	<ol>
		<li>Subtracting support structure
		<ol>
			<li>Wearing gloves, break apart the wrapping supports around the preliminary model and remove most of the main body of the supporting structure.</li>
			<li>Put the model into an ultrasonic cleaner with Ca(OH)2 alkaline solution for a 15 min cleaning.</li>
			<li>Put the model into a wet sandblaster and rinse it until the rest of the support structure on the surface is washed away.</li>
		</ol>
		</li>
		<li>Grinding
		<ol>
			<li>Grind the model with an electric grinder, file, or grinding wheel.</li>
		</ol>
		</li>
		<li>Varnishing 
		NOTE: This process consists of spraying and manually painting.
		<ol>
			<li>Spray the varnish into large-area color blocks on half of the surface of the model. Manually paint the small-area color blocks with varnish.</li>
		</ol>
		</li>
		<li>Curing
		<ol>
			<li>Put the model into a UV curing machine for 30 s of curing.</li>
			<li>Take out the model and clean it with 95% alcohol. 
			NOTE: After the alcohol volatilizes completely, the production is finished.</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>
6. Delivery
<ol>
	<li>Package the thyroid model and complete the delivery to the surgeons before surgery.</li>
</ol>

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The authors declare no conflicts of interest.

Ultrasound may be the only preoperative imaging procedure for most patients undergoing thyroid surgery15. However, a few well-differentiated cases may suffer from advanced diseases, which invade the surrounding tissues or organs and hinder the operation16. This model may be more suitable for patients with far-advanced thyroid cancer. When the disease progresses, additional CT scanning is helpful for further diagnosis. This model is based on CT scanning, which provides more ...

Thyroid nodules are one of the most common endocrine diseases, among which thyroid cancer accounts for 14%-21%1. The preferred treatment for thyroid cancer is surgery. However, because the thyroid gland is located in the anterior cervical area, there are important tissues and organs close to the thyroid gland in the operation area, such as the parathyroid gland, trachea, esophagus, and cervical great vessels and nerves2,3, making the operation relatively difficult and risky. The most common surgical complications are a decrease in parathyroid function caused by parathyroid function injury or mis-resection and hoarseness caused by recurrent laryngeal nerve injury4. The reduction of the above-mentioned surgical complications has always been an objective for surgeons. The most common imaging method before thyroid surgery is ultrasound imaging, although its display of the parathyroid gland and nerve is very limited5. In addition, the variation in the position of the parathyroid gland and the recurrent laryngeal nerve in the thyroid surgery area is very high, which hinders identification6,7. If the anatomical position of each patient can be clearly displayed to the surgeon through the model in real time during the operation, it will reduce the operational risk of thyroid surgery, reduce the incidence of complications, and improve the efficiency of thyroid surgery.
In addition, it is also challenging to thoroughly explain the surgical process to patients before surgery. Some inexperienced surgeons find it difficult to explain and convey the precise details of the operation to patients, especially because of the complexity of the thyroid gland and its surrounding structures. Each patient has their own unique anatomical structure and personal needs8. Therefore, a personalized 3D thyroid model based on the real anatomy of the patient can effectively help patients and clinicians. Currently, the majority of the products on the market are mass-produced based on plane diagrams. By utilizing 3D printing technology to produce a patient-specific model that reflects each patient&#39;s individual medical needs, this model can be used to evaluate the actual condition of patients with thyroid cancer and help surgeons better communicate the nature of the disease with patients.
3D printing (or additive manufacturing) is a three-dimensional construction built from a computer aided design model or digital 3D model9. It has been used in many medical applications, such as medical devices, anatomical models, and drug formulation10. Compared to traditional imaging, a 3D printing model is more visible and more legible. Therefore, 3D printing is increasingly being used in modern surgical procedures. Commonly used 3D-printed technologies include vat polymerization-based printing, powder-based printing, inkjet-based printing, and extrusion-based printing11. In vat polymerization-based printing, a specific wavelength of light is irradiated onto a barrel of light-curing resin, which locally cures the resin one layer at a time. It has the advantages of material saving and fast printing. Powder-based printing relies on localized heating to fuse the powder material for a denser structure, but it also leads to a significant increase in printing time and cost, and is currently in limited use12. Inkjet-based printing uses a precise spraying of droplets onto the substrate in a layer-by-layer process. This technology is the most mature and has the advantages of high material compatibility, controllable cost, and fast printing time13. Extrusion-based printing extrudes materials such as solutions and suspensions through nozzles. This technique utilizes cells and, therefore, has the highest soft tissue-mimicking capabilities. Due to the higher cost and bio-affinity, it is mainly used in the field of tissue engineering and less frequently in surgical organ models14.
As a result, we chose the &#34;White Jet Process&#34; printing technology, based on the complexity of the thyroid and its surrounding structures and the surgical schedule. This technology combines the advantages of vat polymerization-based printing and inkjet-based printing, and offers high precision, fast printing, and low cost, making it a good fit for thyroid surgery. The aim of this protocol is to make a 3D-printed thyroid cancer model, improve the prognosis of patients by providing sufficient information about the anatomical structure and variation of patients, and better inform doctors and patients about all the conditions related to the surgical process.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3D color printer</td>
			<td>Zhuhai Sina 3D Technology Co</td>
			<td>J300PLUS</td>
			<td>Function support: automatic optimized placement, automatic model typesetting, automatic generation support, real-time layered edge cutting and printing, slice export, custom color thickness, custom placement / scaling, man hour evaluation, material consumption evaluation, print status monitoring, material remaining display, changing materials and colors, managing work queues, full / semi enclosed printing, automatic detection of model interference, layer preview, automatic pause of ink shortage, power failure to resume printing Automatic cleaning nozzle, automatic channel adaptation, ink change, automatic cleaning pipeline, follow-up laying. Range of optional materials: RGD series transparent molding materials, RGD series opaque molding materials, FLX series soft molding materials, ABS like series molding materials, high temperature resistant molding materials, Med series molding materials (first-class medical record certification), ordinary supporting materials, water-soluble supporting materials.</td>
		</tr>
		<tr>
			<td>Mimics 21.0 software&#160;</td>
			<td>Materialise, Belgium</td>
			<td></td>
			<td>DICOM data processing</td>
		</tr>
	</tbody>
</table>

a personalized 3d-printed model for preoperative evaluation in thyroid surgery

The anatomic structure of the surgical area of thyroid cancer is complex. It is very important to comprehensively and carefully evaluate the tumor location and its relation with the capsule, trachea, esophagus, nerves, and blood vessels before operation. This paper introduces an innovative 3D-printed model establishment method based on computerized tomography (CT) DICOM images. We established a personalized 3D-printed model of the cervical thyroid surgery field for each patient who needed thyroid surgery to help clinicians evaluate the key points and difficulties of the surgery and select the operation methods of key parts as a basis. The results showed that this model is conducive to preoperative discussion and the formulation of operation strategies. In particular, as a result of the clear display of the recurrent laryngeal nerve and parathyroid gland locations in the thyroid operation field, injury to them can be avoided during surgery, the difficulty of thyroid surgery reduced, and the incidence of postoperative hypoparathyroidism and complications related to recurrent laryngeal nerve injury reduced too. Moreover, this 3D-printed model is intuitive and aids communication for the signing of informed consent by patients before surgery.

This paper presents a protocol for the construction of personalized 3D-printed models of patients&#39; thyroids. Figure 1 shows a flow chart for establishing a personalized 3D-printed model for thyroids of patients. Figure 2 shows the personalized 3D-printed model printing device for thyroids of patients. Figure 3 shows the software interface for the establishment of a personalized 3D-printed model for thyroid patients. The interfac...

Watch this Scientific Journal Video about A Personalized 3D-Printed Model for Preoperative Evaluation in Thyroid Surgery at JoVE.com

A Personalized 3D-Printed Model for Preoperative Evaluation in Thyroid Surgery

Here, a new method of establishing a personalized 3D-printed model for preoperative evaluation of thyroid surgery is proposed. It is conducive to preoperative discussion, reducing the difficulty of thyroid surgery.

The anatomic structure of the surgical area of thyroid cancer is complex. It is very important to comprehensively and carefully evaluate the tumor ...

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1.1K Views.  Sichuan University. Here, a new method of establishing a personalized 3D-printed model for preoperative evaluation of thyroid surgery is proposed. It is conducive to preoperative discussion, reducing the difficulty of thyroid surgery.

Video: A Personalized 3D-Printed Model for Preoperative Evaluation in Thyroid Surgery

Screening for Melanoma Modifiers using a Zebrafish Autochthonous Tumor Model

Genomic studies of human cancers have yielded a wealth of information about genes that are altered in tumors1,2,3. A challenge arising from these studies is that many genes are altered, and it can be difficult to distinguish genetic alterations that drove tumorigenesis from that those arose incidentally during transformation. To draw this distinction it is beneficial to have an assay that can quantitatively measure the effect of an altered gene on tumor initiation and other processes that enable tumors to persist and disseminate. Here we present a rapid means to screen large numbers of candidate melanoma modifiers in zebrafish using an autochthonous tumor model4 that encompasses steps required for melanoma initiation and maintenance. A key reagent in this assay is the miniCoopR vector, which couples a wild-type copy of the mitfa melanocyte specification factor to a Gateway recombination cassette into which candidate melanoma genes can be recombined5. The miniCoopR vector has a mitfa rescuing minigene which contains the promoter, open reading frame and 3'-untranslated region of the wild-type mitfa gene. It allows us to make constructs using full-length open reading frames of candidate melanoma modifiers. These individual clones can then be injected into single cell Tg(mitfa:BRAFV600E);p53(lf);mitfa(lf)zebrafish embryos. The miniCoopR vector gets integrated by Tol2-mediated transgenesis6 and rescues melanocytes. Because they are physically coupled to the mitfa rescuing minigene, candidate genes are expressed in rescued melanocytes, some of which will transform and develop into tumors. The effect of a candidate gene on melanoma initiation and melanoma cell properties can be measured using melanoma-free survival curves, invasion assays, antibody staining and transplantation assays.

A rapid way to screen for melanoma modifiers using a zebrafish autochthonous tumor model is presented. It takes advantage of the miniCoopR vector which allows for expression of candidate melanoma genes in melanocytes. A method to obtain melanoma-free survival curves, an invasion assay, a protocol for antibody staining of scale melanocytes and a melanoma transplantation assay are described.

Genomic studies of  human cancers have yielded a wealth of information about genes that are altered  in tumors1,2,3. A challenge arising from these ...

Evaluation of Tumor-infiltrating Leukocyte Subsets in a Subcutaneous Tumor Model

Specialized immune cells that infiltrate the tumor microenvironment regulate the growth and survival of neoplasia.&#160; Malignant cells must elude or subvert anti-tumor immune responses in order to survive and flourish. Tumors take advantage of a number of different mechanisms of immune &#8220;escape,&#8221; including the recruitment of tolerogenic DC, immunosuppressive regulatory T cells (Tregs), and myeloid-derived suppressor cells (MDSC) that inhibit cytotoxic anti-tumor responses. Conversely, anti-tumor effector immune cells can slow the growth and expansion of malignancies: immunostimulatory dendritic cells, natural killer cells which harbor innate anti-tumor immunity, and cytotoxic T cells all can participate in tumor suppression. The balance between pro- and anti-tumor leukocytes ultimately determines the behavior and fate of transformed cells; a multitude of human clinical studies have borne this out. Thus, detailed analysis of leukocyte subsets within the tumor microenvironment has become increasingly important. Here, we describe a method for analyzing infiltrating leukocyte subsets present in the tumor microenvironment in a mouse tumor model. Mouse B16 melanoma tumor cells were inoculated subcutaneously in C57BL/6 mice. At a specified time, tumors and surrounding skin were resected en bloc and processed into single cell suspensions, which were then stained for multi-color flow cytometry. Using a variety of leukocyte subset markers, we were able to compare the relative percentages of infiltrating leukocyte subsets between control and chemerin-expressing tumors. Investigators may use such a tool to study the immune presence in the tumor microenvironment and when combined with traditional caliper size measurements of tumor growth, will potentially allow them to elucidate the impact of changes in immune composition on tumor growth. Such a technique can be applied to any tumor model in which the tumor and its microenvironment can be resected and processed.

This protocol describes a method for the detailed evaluation of leukocyte subsets within the tumor microenvironment in a mouse tumor model. Chemerin-expressing B16 melanoma cells were implanted subcutaneously into syngeneic mice. Cells from the tumor microenvironment were then stained and analyzed by flow cytometry, allowing for detailed leukocyte subset analyses.

Specialized immune cells that infiltrate the tumor microenvironment regulate the growth and survival of neoplasia.&#160; Malignant cells must elude or ...

An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model

Pedicle screw fixation is the gold standard for the treatment of spinal diseases. However, many studies have reported the issue of loosening pedicle screws after spinal surgery, which is a serious concern. To address this problem, diverse types of pedicle screws have been examined to identify those with good fixation strength and osseointegration in spine bone. The porcine spine is a good alternative for the human spine in the evaluation of pedicle screws due to the anatomical size, mechanical characteristics, and cost. Although several studies have reported that pedicle screws are efficient in the porcine model, no study has described detailed protocols for the evaluation of a pedicle screw using the porcine model. Here, we describe a detailed method for evaluating transpedicular screws using an in vivo porcine lumbar spine model. The technical details for anesthesia, spine surgery, and harvest provided here will facilitate with the evaluation of the transpedicular screw fixation model.

An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model

Here, we introduce a method to evaluate transpedicular screws by using an in vivo porcine lumbar spine model.

Pedicle screw fixation is the gold standard for the treatment of spinal diseases. However, many studies have reported the issue of loosening pedicle ...

Intra-Operative Neural Monitoring of Thyroid Surgery in a Porcine Model

Intraoperative injury to the recurrent laryngeal nerve (RLN) can cause vocal cord paralysis, which interferes with speech and can potentially interfere with breathing. In recent years, intraoperative neural monitoring (IONM) has been widely adapted as an adjunct technique to localize the RLN, detect RLN injury, and predict vocal cord function during the operations. Many studies have also used animal models to investigate new applications of IONM technology and to develop reliable strategies for preventing intraoperative RLN injury. The aim of this article is to introduce a standard protocol for using a porcine model in IONM research. The article demonstrates the procedures for inducing general anesthesia, performing tracheal intubation, and experimental design to investigate the electrophysiological characteristics of RLN injuries. Applications of this protocol can improve overall efficacy in implementing the 3R principle (replacement, reduction and refinement) in porcine IONM studies.

This study aims to develop a standard protocol of intra-operative neural monitoring of thyroid surgery in a porcine model. Here, we present a protocol to demonstrate general anesthesia, to compare different types of electrodes, and to investigate the electrophysiological characteristics of the normal and injured recurrent laryngeal nerves.

Intraoperative injury to the recurrent laryngeal nerve (RLN) can cause vocal cord paralysis, which interferes with speech and can potentially interfere ...

Novel Percutaneous Approach for Deployment of 3D Printed Coronary Stenosis Implants in Swine Models of Ischemic Heart Disease

Minimally invasive methods for creating models of focal coronary narrowing in large animals are challenging. Rapid prototyping using three-dimensionally (3D) printed coronary implants can be employed to percutaneously create a focal coronary stenosis. However, reliable delivery of the implants can be difficult without the use of ancillary equipment. We describe the use of a mother-and-child coronary guide catheter for stabilization of the implant and for effective delivery of the 3D printed implant to any desired location along the length of the coronary vessel. The focal coronary narrowing was confirmed under coronary cineangiography and the functional significance of the coronary stenosis was assessed using gadolinium-enhanced first-pass cardiac perfusion MRI. We showed that reliable delivery of 3D printed coronary implants in swine models (n = 11) of ischemic heart disease can be achieved through repurposing mother-and-child coronary guide catheters. Our technique simplifies the percutaneous delivery of coronary implants to create closed-chest swine models of focal coronary artery stenosis and can be performed expeditiously, with a low procedural failure rate.

We describe a novel, cost-effective, and efficient technique for percutaneous delivery of three-dimensionally printed coronary implants to create closed-chest swine models of ischemic heart disease. The implants were fixed in place using a mother-and-child extension catheter with high success rate.

Minimally invasive methods for creating models of focal coronary narrowing in large animals are challenging. Rapid prototyping using three-dimensionally ...

Standardized Histomorphometric Evaluation of Osteoarthritis in a Surgical Mouse Model

One of the most prevalent joint disorders in the United States, osteoarthritis (OA) is characterized by progressive degeneration of articular cartilage, primarily in the hip and knee joints, which results in significant impacts on patient mobility and quality of life. To date, there are no existing curative therapies for OA able to slow down or inhibit cartilage degeneration. Presently, there is an extensive body of ongoing research to understand OA pathology and discover novel therapeutic approaches or agents that can efficiently slow down, stop, or even reverse OA. Thus, it is crucial to have a quantitative and reproducible approach to accurately evaluate OA-associated pathological changes in the joint cartilage, synovium, and subchondral bone. Currently, OA severity and progression are primarily assessed using the Osteoarthritis Research Society International (OARSI) or Mankin scoring systems. In spite of the importance of these scoring systems, they are semiquantitative and can be influenced by user subjectivity. More importantly, they fail to accurately evaluate subtle, yet important, changes in the cartilage during the early disease states or early treatment phases. The protocol we describe here uses a computerized and semiautomated histomorphometric software system to establish a standardized, rigorous, and reproducible quantitative methodology for the evaluation of joint changes in OA. This protocol presents a powerful addition to the existing systems and allows for more efficient detection of pathological changes in the joint.

The current protocol establishes a rigorous and reproducible method for quantification of morphological joint changes that accompany osteoarthritis. Application of this protocol can be valuable in monitoring disease progression and evaluating therapeutic interventions in osteoarthritis.

One of the most prevalent joint disorders in the United States, osteoarthritis (OA) is characterized by progressive degeneration of articular cartilage, ...

Development and Evaluation of 3D-Printed Cardiovascular Phantoms for Interventional Planning and Training

Catheter-based interventions are standard treatment options for cardiovascular pathologies. Therefore, patient-specific models could help training physicians&#39; wire-skills as well as improving planning of interventional procedures. The aim of this study was to develop a manufacturing process of patient-specific 3D-printed models for cardiovascular interventions.
To create a 3D-printed elastic phantom, different 3D-printing materials were compared to porcine biological tissues (i.e., aortic tissue) in terms of mechanical characteristics. A fitting material was selected based on comparative tensile tests and specific material thicknesses were defined. Anonymized contrast-enhanced CT-datasets were collected retrospectively. Patient-specific volumetric models were extracted from these datasets and subsequently 3D-printed. A pulsatile flow loop was constructed to simulate the intraluminal blood flow during interventions. Models&#39; suitability for clinical imaging was assessed by x-ray imaging, CT, 4D-MRI and (Doppler) ultrasonography. Contrast medium was used to enhance visibility in x-ray-based imaging. Different catheterization techniques were applied to evaluate the 3D-printed phantoms in physicians&#39; training as well as for pre-interventional therapy planning.
Printed models showed a high printing resolution (~30 &#181;m) and mechanical properties of the chosen material were comparable to physiological biomechanics. Physical and digital models showed high anatomical accuracy when compared to the underlying radiological dataset. Printed models were suitable for ultrasonic imaging as well as standard x-rays. Doppler ultrasonography and 4D-MRI displayed flow patterns and landmark characteristics (i.e., turbulence, wall shear stress) matching native data. In a catheter-based laboratory setting, patient-specific phantoms were easy to catheterize. Therapy planning and training of interventional procedures on challenging anatomies (e.g., congenital heart disease (CHD)) was possible.
Flexible patient-specific cardiovascular phantoms were 3D-printed, and the application of common clinical imaging techniques was possible. This new process is ideal as a training tool for catheter-based (electrophysiological) interventions and can be used in patient-specific therapy planning.

Here we present development of a mock circulation setup for multimodal therapy evaluation, pre-interventional planning, and physician-training on cardiovascular anatomies. With the application of patient-specific tomographic scans, this setup is ideal for therapeutic approaches, training, and education in individualized medicine.

Catheter-based interventions are standard treatment options for cardiovascular pathologies. Therefore, patient-specific models could help training ...

Retinal Pathophysiological Evaluation in a Rat Model

A posterior segment eye disease like diabetic retinopathy alters the physiology of the retina. Diabetic retinopathy is characterized by a retinal detachment, breakdown of the blood-retinal barrier (BRB), and retinal angiogenesis. An in vivo rat model is a valuable experimental tool to examine the changes in the structure and function of the retina. We propose three different experimental techniques in the rat model to identify morphological changes of retinal cells, retinal vasculature, and compromised BRB. Retinal histology is used to study the morphology of various retinal cells. Also, quantitative measurement is performed by retinal cell count and thickness measurement of different retinal layers. A BRB breakdown assay is used to determine the leakage of extraocular proteins from the plasma to vitreous tissue due to the breakdown of BRB. Fluorescence angiography is used to study angiogenesis and leakage of blood vessels by visualizing retinal vasculature using FITC-dextran dye.

Diabetic retinopathy is one of the leading causes of blindness. Histology, blood-retinal barrier breakdown assay, and fluorescence angiography are valuable techniques to understand the pathophysiology of the retina, which could further enhance the efficient drug screening against diabetic retinopathy.

A posterior segment eye disease like diabetic retinopathy alters the physiology of the retina. Diabetic retinopathy is characterized by a retinal ...

Establishment and Evaluation of a Porcine Vein Graft Disease Model

Venous graft disease (VGD) is the leading cause of coronary artery bypass graft (CABG) failure. Large animal models of CABG-VGD are needed for the investigation of disease mechanisms and the development of therapeutic strategies. 
To perform the surgery, we enter the cardiac chamber through the third intercostal space and carefully dissect the internal mammary vein and immerse it in normal saline. The right main coronary artery is then treated for ischemia. The target vessel is incised, a shunt plug is placed, and the distal end of the graft vein is anastomosed. The ascending aorta is partially blocked, and the proximal end of the graft vein is anastomosed after perforation. The graft vein is checked for patency, and the proximal right coronary artery is ligated. 
CABG surgery is performed in minipigs to harvest the left internal mammary vein for its use as a vascular graft. Serum biochemical tests are used to evaluate the physiological status of the animals after surgery. Ultrasound examination shows that the proximal, middle, and distal end of the graft vessel are unobstructed. In the surgical model, turbulent blood flow in the graft is observed upon histological examination after the CABG surgery, and venous graft stenosis associated with intimal hyperplasia is observed in the graft. The study here provides detailed surgical procedures for the establishment of a repeatable CABG-induced VGD model.

In this protocol, novel pig vein bypass grafting was performed through a small incision in the left chest wall without cardiopulmonary bypass. A postoperative pathology study was done, which showed intimal thickening.

Venous graft disease (VGD) is the leading cause of coronary artery bypass graft (CABG) failure. Large animal models of CABG-VGD are needed for the ...

Investigation of the Electrophysiological and Thermographic Safety Parameters of Surgical Energy Devices During Thyroid and Parathyroid Surgery in a Porcine Model

In thyroid and parathyroid surgery, surgical energy devices (SEDs) provide more efficient hemostasis than conventional clamp-and-tie hemostasis in areas with rich blood supply. However, when a SED is activated near the recurrent laryngeal nerve (RLN), the heat generated by the SED may injure the nerve irreversibly. To safely apply SEDs in thyroid/parathyroid surgery, this article introduces experimental porcine model studies to investigate the activation and cooling safety parameters of SEDs in standardized electrophysiological (EP) and thermographic (TG) procedures, respectively. In the EP safety parameter experiments, continuous intraoperative neuromonitoring (C-IONM) is applied to demonstrate the RLN function in real-time. The EP activation study evaluates the safe activation distance of SEDs; the EP cooling study evaluates the safe cooling time of SEDs. In the TG safety parameter experiment, a thermal imaging camera is used to record the temperature change after activating the SED. The TG activation study evaluates the lateral thermal spread distance after SED activation in a dry or humid environment and whether smoke and splashing are generated; the TG cooling study evaluates the cooling time. This will help establish the safety parameters of newly developed SEDs used in thyroid/parathyroid surgery and provide safety guidelines to avoid RLN injury and related complications.

The safe application of newly developed surgical energy devices in thyroid/parathyroid surgery attracts the attention of surgeons. Animal experimental models can avoid unnecessary trials and errors in human surgery. This report aims to demonstrate electrophysiological and thermographic methods to evaluate the safety parameters of SEDs in thyroid/parathyroid surgery.

In thyroid and parathyroid surgery, surgical energy devices (SEDs) provide more efficient hemostasis than conventional clamp-and-tie hemostasis in areas ...