This work is supported by grants from Natural Science Fund of Guangdong Province (No. 2017A030313597) and Southern Medical University (No. LX2016N006, No. KJ20161102).

1. Drawing a two dimensional (2D)-image of a burr hole ring
<ol>
	<li>Open the 2D computer aided design (CAD) software and then create a graphical document.</li>
	<li>Click Draw | Line and draw a reference point with a solid line on the drawing. Click Modify | Offset, and type the specific offset distance in the command line.</li>
	<li>Click on the object and press by the left mouse button to create a solid line. Click Modify | Trim, select the area to be trimmed and click on the extra line.</li>
	<li>Take the inner burr hole ring for example, draw three different views of the inner ring based on the predetermined size in the CAD software. First, draw the front view and modify the graph carefully until it matches the structure expected (Figure 1d).</li>
	<li>Draw the top view by clicking Draw | Line to construct the reference point first and then click on Draw | Circle | Center, Diameter, and input the quantitative value of specific radius of circle or diameter in the command window. Click on the center of the reference point to form a circle (Figure 1f).</li>
	<li>Draw the left view of the inner burr hole ring with the same approach as that of the front view (Figure 1e).</li>
	<li>Click on Dimension | Diameter, and then click on the circumference to mark the diameter of the circle (Figure 1f).</li>
	<li>Click on Dimension | Linear and mark the length and thickness of all associated structures (Figure 1d,e). Click Dimension | Radius to mark the angle of the chamber (Figure 1d).</li>
	<li>Using the same protocol, construct two-dimensional drawings of the outer burr hole ring, and mark the actual size and the labeling (Figure 1a - c).</li>
	<li>Add technical requirements of the production process, including strength, toughness and lack of cracks. Moreover, smoothing of the outer wall is needed.</li>
	<li>Clink on Save to save the 2D-image of the burr hole ring. 
	NOTE: All of these structures mentioned above are in the units of millimeters (mm).</li>
</ol>
2. Construction of a 3D-image of the burr hole ring
<ol>
	<li>Start the 3D drawing software (see the Table of Materials). Select New | Part | Solid and uncheck using the default template. Select part_solid in new file options and click on Ok to create a new interface for setting up a physical part model.</li>
	<li>Click on Part feature in the menu manager on the right and select Create | Solid | Add sheet. In the SOLID drop-down menu, select Rotate | Done. Click on the trace of the preliminary sketch. Select the &#34;front&#34; plane as the sketch plane, then click default under SKET VIEW.</li>
	<li>Select the dotted line on the right toolbar of the window and draw the top section of the part in the two-dimensional sketch. The specific size shall be subject to the two-dimensional drawing. Then click Conform, and select Done in the Protrusion window of protrusion. Click on the Datum plane icon.</li>
	<li>In menu manager, select Create | Solid | Add sheet, and Rotate | Done. Click Bilateral in the properties menu and click Done.</li>
	<li>Click on Front | Forward | Default and then Datum plane | Dotted Line to construct the cross section of the hook of the outer burr hole ring. Then click Conform followed by Done in menu manager. Input &#34;50&#34;&#160;in Angle in indicated direction[45.0000], and then click Done in the Protrusion window and finally, click on the Coloring button. 
	NOTE: The unit of the angle is degree (&#176;).</li>
	<li>Select Redefine in the part feature and click the line structure of the hook. Input the command Section | Define | Sketch.</li>
	<li>Click the Dotted line icon, create two square embossments on the hook section, then input command OK | Done | Coloring.</li>
	<li>Click the Datum axis icon, then input the command Insert a datum | Cross, click the center axis of the line structure, click Angle in datum plane, and then click the &#34;front&#34; plane in the line structure view. Click input value in the offset menu. Input &#34;-45&#34; in &#34;Angle in indicated direction[45.0000]. 
	NOTE: The unit of the angle is degree (&#176;).</li>
	<li>Click on Features | Copy | Mirror. Click on the hook as the object and input command Done select | Done. Click the datum plane to complete the copy. Similarly, the remaining two hooks are copied in this way. Click on Create concentric circle to construct a circle with a radius of 7.23 mm, click the Segmentation of primitives at selected points icon to remove the unnecessary lines of the circle.</li>
	<li>Click the Solid line button in the right toolbar to create a complete outer wall section. Then input the command OK | Done. 
	NOTE: The unit of the radius is millimeter (mm).</li>
	<li>Input &#34;4&#34; in Enter depth, then click on Coloring. Input the command Mirror | Done. Then click on the object and click Done. Click the datum plane to complete the copy.</li>
	<li>Input the command Copy | Mirror | Done, and select two outer walls in different directions, click Done to conform. Click the datum plane to complete the copy.</li>
	<li>Input the command View | Model Settings | Color and appearance | Add. Adjust the RGB color slider and adjust the color to brown to show the graphic details more visually. Then input the command Close | Settings | OK.</li>
	<li>Click the button Eliminating hidden lines, click the Create concentric circle, continue to create an outer edge on the outer wall, click the Segmentation of primitives at selected points button to remove excess lines, and click the Solid line button to connect the newly added outer edge into a complete section. Click Ok.</li>
	<li>Input &#34;0.8&#34; in Inter depth. Click Ok in the Protrusion window. In menu manager, input the command Copy | Mirror | Done. Click the object and click done. Input the command Generate benchmark | Offset. 
	NOTE: The unit of the depth is millimeter (mm).</li>
	<li>Click the Input value in the Offset and enter &#34;0.4&#34; as the Isometric of the specified direction, then click Done. 
	NOTE: The unit of the offset is millimeter (mm).</li>
	<li>Input the command Copy | Mirror | Done, click the outer wall. Input the command Done select | Done. Click Done select and click Done. Click the datum of the image to complete the copy. In this way, the mirror operation of the outer wall and the square embossing is completed respectively.</li>
	<li>Input the command File | Copy, select save format as STL (*stl) in the part type drop-down menu, enter part number and click Ok.</li>
	<li>In the Output STL dialog box, adjust the chord height to 0.006 and the angle control to 0.00001. Input the command Apply | OK.</li>
	<li>Use the same methods as above to build the 3D image of the inner ring.</li>
</ol>
3. Using 3D printer to print the physical model of burr hole ring
<ol>
	<li>Open the model detecting software, input the command Project | Open, choose one STL file in the Open file pop-up dialog box, then click Open. In this software, a warning will appear if defects are detected in this model (Figure 3). If found, repair the model before printing. If there are no defects, click Output.</li>
	<li>After confirming that the outer ring is complete, input the command Part | Export part | as STL | Save. Use the above instructions to detect the defects of the inner ring.</li>
	<li>Following model detection, the printed path needs to be designed. Open the slicing software, click File | Load model file, click on one STL file and click Open to import.</li>
	<li>Click the left mouse button to choose the moving track of the part, adjust the position of parts. On the left side of the screen, set the print speed to 30 mm/s, printing temperature to 210 &#176;C and bed temperature to 80 &#176;C (Figure 4).</li>
	<li>Click Toolpath to SD to save the file in Gcode format to generate printed path (Figure 3).</li>
	<li>Start the 3D printers, click the Preheating button on the main interface, set the preheat temperature of the bed to 80 &#176;C and the nozzle temperature to 210 &#176;C. Click Print when the temperature rises to the preset value, select the target file and click Confirm to start printing.</li>
	<li>The outer ring will be printed first (Figure 5a). After the bottom supporting grid has been constructed, the printing nozzle begins to construct the outer ring vertically layer by layer (Figure 5b - d). This process takes about 13 min.</li>
	<li>After the outer ring is formed, the printer nozzle continues to make the inner ring on the right side (Figure 5c,d), which takes about 8 min.</li>
	<li>Remove both parts from the platform after cooling and being formed (Figure 5e,f).</li>
</ol>
4. Measurement of absolute error
<ol>
	<li>To measure the absolute error, select five printed parts randomly. Measure and record the parameters of each part with Vernier calipers. Choose the measurement accuracy at 0.02 mm.</li>
	<li>Calculate the mean error of each part and the error range of the absolute error (Figure 6a,b).</li>
</ol>

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The authors have nothing to disclose.

These results showed that the software used were practicable to build 3D models of burr hole rings (Figure 1 and Figure 2), and 3D printing can be used to build solid models with designated materials (Figure 4). In terms of the size of the solid model, there was an absolute error from 0 to 0.59 mm determined through the measurement made by Vernier calipers (Figure 6). To some extent, the error is unavoi...

3D printing has been applied in the medical field since the 1980s, especially in surgery for preoperative simulation, anatomical learning and surgical training1. For example, in cerebrovascular operations, preoperative simulation can be conducted by using 3D printed vascular models2. With the development of 3D printing, the texture, temperature, structure and weight of cerebral blood vessels can be simulated to the greatest extent of clinical scenarios. Trainees can perform surgical operations such as cutting and clamping on such models. This training is very important for the surgeons3,4,5. Currently, titanium patches formed by 3D printing have also gradually been applied6, since the skull prostheses developed by 3D printing after imaging and reconstruction are highly conformal. However, the development and application of 3D printing in neurosurgery is still limited.
The burr hole ring, as a part of the lead fixation device, has been widely used in deep brain stimulation (DBS)7,8,9,10. However, current burr hole rings are made by medical device manufacturers according to the unified specifications and dimensions. This standard burr hole ring is not always suitable for all conditions, such as skull malformation and scalp atrophy. It may increase the uncertainties of operation and reduce the acurracy. The emergence of 3D printing makes it possible to develop individualized burr hole rings for patients in clinical scenarios5. At the same time, the burr hole ring, which is not easy to obtain, is not conducive to extensive preoperative demonstration and surgical training1.
To address the problems mentioned above, we proposed to construct a burr hole ring with 3D printing. A previous study in our lab described an innovative burr hole ring for DBS11. In this study, this innovative burr hole ring will be regarded as an excellent example to exhibit the detailed production process. Therefore, the purpose of this study is to provide a modeling process and a detailed technical process of building a solid burr hole ring using 3D printing.

<table><tbody><tr><td>Adobe Photoshop Version 14.0</td><td>Adobe System?US</td><td>_</td><td>Only available with a paid subscription.</td></tr><tr><td>Allcct 3D printer</td><td>Allcct technology co., LTD, WuHan, China</td><td>201807A794124CN</td><td></td></tr><tr><td>Allcct_YinKe_V1.1</td><td>Allcct technology co., LTD, WuHan, China</td><td></td><td>The software is provided by the 3D printer manufacturer and there is no Catalog number associated with it</td></tr><tr><td>AutoCAD 2004</td><td>Autodesk co., LTD?US</td><td>666-12345678</td><td>Software for 2D models</td></tr><tr><td>Carbon Fibre</td><td>Allcct technology co., LTD, WuHan, China</td><td>PLA175&amp;Oslash;5181&amp;Oslash;3&amp;Oslash;B</td><td>The material is provided by the 3D printer manufacturer</td></tr><tr><td>Netfabb Studio Basic 4.9</td><td>Autodesk co., LTD?US</td><td>-</td><td>The software is provided by a 3D printer manufacturer and is open to access</td></tr><tr><td>Pro/E 2001</td><td>Parametric Technology Corporation, PTC, US</td><td>_</td><td>Software for 3D models; Only available with a paid subscription.</td></tr><tr><td>Vernier caliper&amp;nbsp;</td><td>&amp;nbsp;Beijing Blue Light Machinery Electricity Instrument Co,. LTD, China</td><td>GB/T&amp;ensp;1214.1-1996&amp;ensp;</td><td></td></tr></tbody></table>

application of 3d printing in the construction of burr hole ring for deep brain stimulation implants

3D printing has been widely applied in the medical field since the 1980s, especially in surgery, such as preoperative simulation, anatomical learning and surgical training. This raises the possibility of using 3D printing to construct a neurosurgical implant. Our previous works took the construction of the burr hole ring as an example, described the process of using softwares like computer aided design (CAD), Pro/Engineer (Pro/E) and 3D printer to construct physical products. That is, a total of three steps are required, the drawing of 2D-image, the construction of 3D-image of burr hole ring, and using a 3D printer to print the physical model of burr hole ring. This protocol shows that the burr hole ring made of carbon fiber can be rapidly and accurately molded by 3D printing. It indicated that both CAD and Pro/E softwares can be used to construct the burr hole ring via integrating with the clinical imaging data and further applied 3D printing to make the individual consumables.

Three views of 2D images were built through commercial CAD software (see the Table of Materials). In these images, practical size and technical requirements have also been added (Figure 1). Further, three-dimensional data were constructed in (Figure 2) and saved in STL format (Figure 3). As presented in Figure 4, solid parts were built on the platform of...

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Application of 3D Printing in the Construction of Burr Hole Ring for Deep Brain Stimulation Implants

Here, we present a protocol to demonstrate 3D printing in the construction of deep brain stimulation implants.

3D printing has been widely applied in the medical field since the 1980s, especially in surgery, such as preoperative simulation, anatomical learning and ...

application-3d-printing-construction-burr-hole-ring-for-deep-brain

Research

JoVE Journal

Behavior

6.8K Views.  Southern Medical University. Here, we present a protocol to demonstrate 3D printing in the construction of deep brain stimulation implants.

Video: Application of 3D Printing in the Construction of Burr Hole Ring for Deep Brain Stimulation Implants

Design and Fabrication of Ultralight Weight, Adjustable Multi-electrode Probes for Electrophysiological Recordings in Mice

The number of physiological investigations in the mouse, mus musculus, has experienced a recent surge, paralleling the growth in methods of genetic targeting for microcircuit dissection and disease modeling. The introduction of optogenetics, for example, has allowed for bidirectional manipulation of genetically-identified neurons, at an unprecedented temporal resolution. To capitalize on these tools and gain insight into dynamic interactions among brain microcircuits, it is essential that one has the ability to record from ensembles of neurons deep within the brain of this small rodent, in both head-fixed and freely behaving preparations. To record from deep structures and distinct cell layers requires a preparation that allows precise advancement of electrodes towards desired brain regions. To record neural ensembles, it is necessary that each electrode be independently movable, allowing the experimenter to resolve individual cells while leaving neighboring electrodes undisturbed. To do both in a freely behaving mouse requires an electrode drive that is lightweight, resilient, and highly customizable for targeting specific brain structures.
A technique for designing and fabricating miniature, ultralight weight, microdrive electrode arrays that are individually customizable and easily assembled from commercially available parts is presented. These devices are easily scalable and can be customized to the structure being targeted; it has been used successfully to record from thalamic and cortical regions in a freely behaving animal during natural behavior.

Understanding the neural substrates of behavior requires brain circuit ensemble recording. Because of its genetic tractability, the mouse offers a model for circuit dissection and disease mimicry. Here, a method of designing and fabricating miniaturized probes is described that is suitable for targeting deep brain structure in the mouse.

The number of physiological investigations in the mouse, mus musculus, has experienced a recent surge, paralleling the growth in methods of genetic ...

Neuroscience

Fabrication of Custom Agarose Wells for Cell Seeding and Tissue Ring Self-assembly Using 3D-Printed Molds

Engineered tissues are being used clinically for tissue repair and replacement, and are being developed as tools for drug screening and human disease modeling. Self-assembled tissues offer advantages over scaffold-based tissue engineering, such as enhanced matrix deposition, strength, and function. However, there are few available methods for fabricating 3D tissues without seeding cells on or within a supporting scaffold. Previously, we developed a system for fabricating self-assembled tissue rings by seeding cells into non-adhesive agarose wells. A polydimethylsiloxane (PDMS) negative was first cast in a machined polycarbonate mold, and then agarose was gelled in the PDMS negative to create ring-shaped cell seeding wells. However, the versatility of this approach was limited by the resolution of the tools available for machining the polycarbonate mold. Here, we demonstrate that 3D-printed plastic can be used as an alternative to machined polycarbonate for fabricating PDMS negatives. The 3D-printed mold and revised mold design is simpler to use, inexpensive to produce, and requires significantly less agarose and PDMS per cell seeding well. We have demonstrated that the resulting agarose wells can be used to create self-assembled tissue rings with customized diameters from a variety of different cell types. Rings can then be used for mechanical, functional, and histological analysis, or for fabricating larger and more complex tubular tissues.

This protocol describes a platform for fabricating self-assembled tissue rings in variable sizes using a customized 3D-printed plastic mold. PDMS negatives are cured in the 3D-printed mold; then agarose is cast in the cured PDMS negatives. Cells are seeded into the resulting agarose wells where they aggregate into tissue rings.

Engineered tissues are being used clinically for tissue repair and replacement, and are being developed as tools for drug screening and human disease ...

Bioengineering

Microelectrode Guided Implantation of Electrodes into the Subthalamic Nucleus of Rats for Long-term Deep Brain Stimulation

Deep brain stimulation (DBS) is a widely used and effective therapy for several neurologic disorders, such as idiopathic Parkinson&#8217;s disease, dystonia or tremor. DBS is based on the delivery of electrical stimuli to specific deep anatomic structures of the central nervous system. However, the mechanisms underlying the effect of DBS remain enigmatic. This has led to an interest in investigating the impact of DBS in animal models, especially in rats. As DBS is a long-term therapy, research should be focused on molecular-genetic changes of neural circuits that occur several weeks after DBS. Long-term DBS in rats is challenging because the rats move around in their cage, which causes problems in keeping in place the wire leading from the head of the animal to the stimulator. Furthermore, target structures for stimulation in the rat brain are small and therefore electrodes cannot easily be placed at the required position. Thus, a set-up for long-lasting stimulation of rats using platinum/iridium electrodes with an impedance of about 1 M&#937; was developed for this study. An electrode with these specifications allows for not only adequate stimulation but also recording of deep brain structures to identify the target area for DBS. In our set-up, an electrode with a plug for the wire was embedded in dental cement with four anchoring screws secured onto the skull. The wire from the plug to the stimulator was protected by a stainless-steel spring. A swivel was connected to the circuit to prevent the wire from becoming tangled. Overall, this stimulation set-up offers a high degree of free mobility for the rat and enables the head plug, as well as the wire connection between the plug and the stimulator, to retain long-lasting strength.

A method for implanting electrodes into the subthalamic nucleus (STN) of rats is described. Better localization of the STN was achieved by using a microrecording system. Furthermore, a stimulation set-up is presented that is characterized by long-lasting connections between the head of the animal and the stimulator.

Deep brain stimulation (DBS) is a widely used and effective therapy for several neurologic disorders, such as idiopathic Parkinson&#8217;s disease, ...

Targeting Neuronal Fiber Tracts for Deep Brain Stimulation Therapy Using Interactive, Patient-Specific Models

Deep brain stimulation (DBS), which involves insertion of an electrode to deliver stimulation to a localized brain region, is an established therapy for movement disorders and is being applied to a growing number of disorders. Computational modeling has been successfully used to predict the clinical effects of DBS; however, there is a need for novel modeling techniques to keep pace with the growing complexity of DBS devices. These models also need to generate predictions quickly and accurately. The goal of this project is to develop an image processing pipeline to incorporate structural magnetic resonance imaging (MRI) and diffusion weighted imaging (DWI) into an interactive, patient specific model to simulate the effects of DBS. A virtual DBS lead can be placed inside of the patient model, along with active contacts and stimulation settings, where changes in lead position or orientation generate a new finite element mesh and solution of the bioelectric field problem in near real-time, a timespan of approximately 10 seconds. This system also enables the simulation of multiple leads in close proximity to allow for current steering by varying anodes and cathodes on different leads. The techniques presented in this paper reduce the burden of generating and using computational models while providing meaningful feedback about the effects of electrode position, electrode design, and stimulation configurations to researchers or clinicians who may not be modeling experts.

The goal of this project is to develop an interactive, patient-specific modeling pipeline to simulate the effects of deep brain stimulation in near real-time and provide meaningful feedback as to how these devices influence neural activity in the brain.

Deep brain stimulation (DBS), which involves insertion of an electrode to deliver stimulation to a localized brain region, is an established therapy for ...

Surgical Training for the Implantation of Neocortical Microelectrode Arrays Using a Formaldehyde-fixed Human Cadaver Model

This protocol describes a procedure to assist surgeons in training for the implantation of microelectrode arrays into the neocortex of the human brain. Recent technological progress has enabled the fabrication of microelectrode arrays that allow recording the activity of multiple individual neurons in the neocortex of the human brain. These arrays have the potential to bring unique insight onto the neuronal correlates of cerebral function in health and disease. Furthermore, the identification and decoding of volitional neuronal activity opens the possibility to establish brain-computer interfaces, and thus might help restore lost neurological functions. The implantation of neocortical microelectrode arrays is an invasive procedure requiring a supra-centimetric craniotomy and the exposure of the cortical surface; thus, the procedure must be performed by an adequately trained neurosurgeon. In order to provide an opportunity for surgical training, we designed a procedure based on a human cadaver model. The use of a formaldehyde-fixed human cadaver bypasses the practical, ethical and financial difficulties of surgical practice on animals (especially non-human primates) while preserving the macroscopic structure of the head, skull, meninges and cerebral surface and allowing realistic, operating room-like positioning and instrumentation. Furthermore, the use of a human cadaver is closer to clinical daily practice than any non-human model. The major drawbacks of the cadaveric simulation are the absence of cerebral pulsation and of blood and cerebrospinal fluid circulation. We suggest that a formaldehyde-fixed human cadaver model is an adequate, practical and cost-effective approach to ensure proper surgical training before implanting microelectrode arrays in the living human neocortex.

We designed a procedure in which a formaldehyde-fixed human cadaver is used to assist neurosurgeons in training for the implantation of microelectrode arrays into the neocortex of the human brain.

This protocol describes a procedure to assist surgeons in training for the implantation of microelectrode arrays into the neocortex of the human brain. ...

Medicine

Automated 3D Brain and Skull Modeling from MRI for NHP Neurosurgical Planning

A Neural Implant Design Toolbox for Nonhuman Primates

This paper describes an in-house method of 3D brain and skull modeling from magnetic resonance imaging (MRI) tailored for nonhuman primate (NHP) neurosurgical planning. This automated, computational software-based technique provides an efficient way of extracting brain and skull features from MRI files as opposed to traditional manual extraction techniques using imaging software. Furthermore, the procedure provides a method for visualizing the brain and craniotomized skull together for intuitive, virtual surgical planning. This generates a drastic reduction in time and resources from those required by past work, which relied on iterative 3D printing. The skull modeling process creates a footprint that is exported into modeling software to design custom-fit cranial chambers and headposts for surgical implantation. Custom-fit surgical implants minimize gaps between the implant and the skull that could introduce complications, including infection or decreased stability. By implementing these pre-surgical steps, surgical and experimental complications are reduced. These techniques can be adapted for other surgical processes, facilitating more efficient and effective experimental planning for researchers and, potentially, neurosurgeons.

Author Spotlight: Streamlined Brain and Skull Modeling for Enhanced Neurosurgical Planning in NHP Research

This paper outlines automated processes for nonhuman primate neurosurgical planning based on magnetic resonance imaging (MRI) scans. These techniques use procedural steps in programming and design platforms to support customized implant design for NHPs. The validity of each component can then be confirmed using three-dimensional (3D) printed life-size anatomical models.

This paper describes an in-house method of 3D brain and skull modeling from magnetic resonance imaging (MRI) tailored for nonhuman primate (NHP) ...

Multicolor 3D Printing of Complex Intracranial Tumors in Neurosurgery

Three-dimensional (3D) printing technologies offer the possibility of visualizing patient-specific pathologies in a physical model of correct dimensions. The model can be used for planning and simulating critical steps of a surgical approach. Therefore, it is important that anatomical structures such as blood vessels inside a tumor can be printed to be colored not only on their surface, but throughout their whole volume. During simulation this allows for the removal of certain parts (e.g., with a high-speed drill) and revealing internally located structures of a different color. Thus, diagnostic information from various imaging modalities (e.g., CT, MRI) can be combined in a single compact and tangible object.
However, preparation and printing of such a fully colored anatomical model remains a difficult task. Therefore, a step-by-step guide is provided, demonstrating the fusion of different cross-sectional imaging data sets, segmentation of anatomical structures, and creation of a virtual model. In a second step the virtual model is printed with volumetrically colored anatomical structures using a plaster-based color 3D binder jetting technique. This method allows highly accurate reproduction of patient-specific anatomy as shown in a series of 3D-printed petrous apex chondrosarcomas. Furthermore, the models created can be cut and drilled, revealing internal structures that allow for simulation of surgical procedures.

The protocol describes the fabrication of fully colored three-dimensional prints of patient-specific, anatomical skull models to be used for surgical simulation. The crucial steps of combining different imaging modalities, image segmentation, three-dimensional model extraction, and production of the prints are explained.

Three-dimensional (3D) printing technologies offer the possibility of visualizing patient-specific pathologies in a physical model of correct dimensions. ...

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 ...

Applications of 3D-Printing for Micro-Scale Neuronal Cell Culture Devices

Two-Photon Polymerization 3D-Printing of Micro-scale Neuronal Cell Culture Devices

Neuronal cultures have been a reference experimental model for several decades. However, 3D cell arrangement, spatial constraints on neurite outgrowth, and realistic synaptic connectivity are missing. The latter limits the study of structure and function in the context of compartmentalization and diminishes the significance of cultures in neuroscience. Approximating ex vivo the structured anatomical arrangement of synaptic connectivity is not trivial, despite being key for the emergence of rhythms, synaptic plasticity, and ultimately, brain pathophysiology. Here, two-photon polymerization (2PP) is employed as a 3D printing technique, enabling the rapid fabrication of polymeric cell culture devices using polydimethyl-siloxane (PDMS) at the micrometer scale. Compared to conventional replica molding techniques based on microphotolitography, 2PP micro-scale printing enables rapid and affordable turnaround of prototypes. This protocol illustrates the design and fabrication of PDMS-based microfluidic devices aimed at culturing modular neuronal networks. As a proof-of-principle, a two-chamber device is presented to physically constrain connectivity. Specifically, an asymmetric axonal outgrowth during ex vivo development is favored and allowed to be directed from one chamber to the other. In order to probe the functional consequences of unidirectional synaptic interactions, commercial microelectrode arrays are chosen to monitor the bioelectrical activity of interconnected neuronal modules. Here, methods to 1) fabricate molds with micrometer precision and 2) perform in vitro multisite extracellular recordings in rat cortical neuronal cultures are illustrated. By decreasing costs and future widespread accessibility of 2PP 3D-printing, this method will become more and more relevant across research labs worldwide. Especially in neurotechnology and high-throughput neural data recording, the ease and rapidity of prototyping simplified in vitro models will improve experimental control and theoretical understanding of in vivo large-scale neural systems.

Author Spotlight: Modular Neuronal Networks for Analyzing Brain Functions

3D printing at the micrometer scale enables rapid prototyping of polymeric devices for neuronal cell cultures. As a proof-of-principle, structural connections between neurons were constrained by creating barriers and channels influencing neurite outgrowth, while the functional consequences of such manipulation were observed by extracellular electrophysiology.

Neuronal cultures have been a reference experimental model for several decades. However, 3D cell arrangement, spatial constraints on neurite outgrowth, ...

A Cost-Effective, Versatile Probe Implant System for Electrophysiology in Mice

The DREAM Implant: A Lightweight, Modular, and Cost-Effective Implant System for Chronic Electrophysiology in Head-Fixed and Freely Behaving Mice

Chronic electrophysiological recordings in rodents have significantly improved our understanding of neuronal dynamics and their behavioral relevance. However, current methods for chronically implanting probes present steep trade-offs between cost, ease of use, size, adaptability, and long-term stability.
This protocol introduces a novel chronic probe implant system for mice called the DREAM (Dynamic, Recoverable, Economical, Adaptable, and Modular), designed to overcome the trade-offs associated with currently available options. The system provides a lightweight, modular and cost-effective solution with standardized hardware elements that can be combined and implanted in straightforward steps and explanted safely for recovery and multiple reuse of probes, significantly reducing experimental costs.
The DREAM implant system integrates three hardware modules: (1) a microdrive that can carry all standard silicon probes, allowing experimenters to adjust recording depth across a travel distance of up to 7 mm; (2) a three-dimensional (3D)-printable, open-source design for a wearable Faraday cage covered in copper mesh for electrical shielding, impact protection, and connector placement, and (3) a miniaturized head-fixation system for improved animal welfare and ease of use. The corresponding surgery protocol was optimized for speed (total duration: 2 h), probe safety, and animal welfare.
The implants had minimal impact on animals&#39; behavioral repertoire, were easily applicable in freely moving and head-fixed contexts, and delivered clearly identifiable spike waveforms and healthy neuronal responses for weeks of post-implant data collection. Infections and other surgery complications were extremely rare.
As such, the DREAM implant system is a versatile, cost-effective solution for chronic electrophysiology in mice, enhancing animal well-being, and enabling more ethologically sound experiments. Its design simplifies experimental procedures across various research needs, increasing accessibility of chronic electrophysiology in rodents to a wide range of research labs.

Here, we introduce a lightweight, cost-effective probe implant system for chronic electrophysiology in rodents optimized for ease of use, probe recovery, experimental versatility, and compatibility with behavior.

Chronic electrophysiological recordings in rodents have significantly improved our understanding of neuronal dynamics and their behavioral relevance. ...