Jump to content
  • entries
    47
  • comments
    60
  • views
    672,643

About this blog

Musings about biomedical 3D printing

Entries in this blog

 

3D Printing the Skull of Richard III

Researchers at the University of Leicester and Loughborough University have successfully 3D printed the skull of Richard III, the last Plantagenet King of England. For those of you rusty in your English history (as I am), Richard III was killed in battle at the Battle of Bosworth Field in 1485. This was the final major battle of the Wars of the Roses. The victor, Henry Tudor, went on to become King of England and founded the Tudor dynasty.   Richard III was buried in a nearby friary shortly after the battle, but the location of the friary was lost to antiquity. In 2012 the friary was discovered underneath a parking lot in Leicester, England and the subsequent excavation revealed the skeletal remains of the English King. The skeleton bore evidence of multiple traumatic injuries, especially to the skull, where there were multiple puncture and cleaving injuries. Additionally, there was significant scoliotic deformity of the spine, which is consistent with the famed hunchback appearance of the King. (Technically hunchbacks have kyphosis, not scoliosis, but close enough.)   To better illustrate the battle injuries and spinal deformities, and preserve the original bones, researchers performed CT scans of the bones and re-created them using 3D printing. They used the Mimics Innovation Suite from Materialise and printed the bones using laser sintering.     The Smithsonian Channel did a fascinating documentary about the excavation, including how they confirmed the identity of the skeleton using mitochondrial DNA via an unbroken line of maternal descendents (mitochondrial DNA is only passed from mother to child) to a Canadian furniture maker whose mitochondrial DNA exactly matched that extracted from the skeleton. Check out the Smithsonian Channel website for some additional details. Thumbnail photo credit: Andrew Weekes Photography

Dr. Mike

Dr. Mike

 

3D printed skull base generated from CT scan data accurately demonstrates complex skull base anatomy.

The base of the skull is one of the most complex and difficult parts of the body for doctors in training to master. And one of the most important. It is comprised of multiple bones (the ethmoid, sphenoid, occipital, frontal, parietal, and temporal, to be exact) and has numerous foramina (holes) through which arteries, veins, and the vital cranial nerves and spinal cord exit the skull on their way to and from the body.   These structures, although very small, are critically important clinically. Compromise of a tiny foramen (hole) can lead to deafness, blindness, paralysis, or even stroke or death. Because of the importance of this small space, medical students around the world struggle to learn the complexities and subtleties of skull base anatomy.   Unfortunately, pictures in an anatomy book just don't cut it. Real human skulls can demonstrate this anatomy well, but these are expensive and the skull has to be cut and opened in order to display the relevant anatomy. This is why I created a 3D printed skull base from real CT scan data.   Available in full size and half-size models, the skull base exhibits exquisite anatomical detail. Digital files of the skull base are available for free download in full size (STL, COLLADA) and half-size (STL, COLLADA) versions.   Very high resolution prints are available for a fee at Shapeways in both full-size and half-size. The half-size model is quite inexpensive so you don't have to worry if it is damaged by rough handling of multiple students.   In the near future I will be posting more anatomical digital models.   For updates on news and new blog entries, follow us on Twitter at @Embodi3D

Dr. Mike

Dr. Mike

 

3D printed models help with surgery for complex congenital heart disease

Researchers at the Children's National Medical Center in Washington DC have used 3D printed heart models to aid repair of congenital heart defects. In the International Journal of Cardiology, the researchers report the case of a patient with transposition of the great arteries, a congenital heart defect in which the pulmonary artery and aorta are switched. Without treatment this condition is fatal in infancy. The man apparently had surgical treatment as a child, but as an adult began to have problems when the surgical conduit allowing his heart to function properly began to close.   A 3D printed replica of the heart was created with Mimics software from the Materialise. The heart was then printed using an Objet Polyjet printer. The investigators tested a variety of catheters and planned the procedure using the model before attempting the actual procedure on the patient. The investigators even deployed a stent within the model for practice. With the benefit of testing on the 3D model, the procedure went as planned. The narrowing was opened with a stent and the heart function returned to normal.   3D printed vascular models have been used recently to assist in planning complex and unusual procedures. They've been used for treating abdominal aortic aneurysms, and now for treating postoperative congenital heart disease. I have personally created a 3D model to help with treatment of a rare vascular anomaly (publication pending, stay tuned). When will 3D models be used for bread-and-butter procedures? What are the barriers to this happening? Please leave a comment.     For updates on news and new blog entries, follow us on Twitter at @Embodi3D Image source: International Journal of Cardiology

Dr. Mike

Dr. Mike

 

3D printed half-skull from CT scan shows detailed skull anatomy for students. Files available for free download.

This is the second in a series of articles about skull models created from CT scan data and designed to provide a low-cost means of anatomy teaching. To see my past article about the skull base model, click here. Learning detailed anatomy is a grueling process that doctors, nurses, and other health science students must go through. Traditionally, learning anatomy involved detailed study of textbooks, but learning 3D structures from 2D pages just doesn't work well. Dissecting cadavers is the traditional means of teaching doctors, but this process is tedious, messy, very expensive, and only available in select educational institutions (i.e. med schools). Most students of anatomy do not have access to these resources. 3D printing is putting the power of real 3D anatomy within reach of ordinary students at very low cost. These models are created from highly detailed CT scan data from real human bodies, not an artist's conceptualization. This half skull and cervical spine has been cut along median sagittal plane. This clearly shows the external bony anatomy (zygomatic arch, orbit, etc.) as well as intracranial anatomy (skull base formina, paranasal sinuses, etc.). Bony details of the cervical spine are also clearly shown.     You can 3D print your own model by downloading the free files. These files are available on this website in STL or COLLADA format, in full size and half-size versions. You can get them here: full size (STL, COLLADA), half-size (STL, COLLADA). Check out more downloadable files in the File Vault.   If you would rather have a high quality model made for you, you can buy one from Shapeways here (full-size, half-size). Feel free to modify the files as you would like, just please don't use them for commercial purposes. If you create something cool, please give back to the community by sharing it on the Embodi3d website in the File Vault.   For updates on news and new blog entries, follow us on Twitter at @Embodi3D

Dr. Mike

Dr. Mike

 

Radbuz.com

I apologize for being slow with the posting recently. I was at a conference last week and this week I have been working on creating a 3D printable cardiac and arterial model (see image). More interesting blog articles will be coming shortly.   In the meantime, I encourage you to check out the blog of my friend, neuroradiologist, and 3D printing enthusiast Jenny Chen, MD., at Radbuz.com. You can follow her on twitter at @radbuzzz.

Dr. Mike

Dr. Mike

 

3D printed white matter tracts illustrate the beauty and complexity of the human brain

Thanks to 3D printing understanding of the complex neural pathways of the human brain became a little bit easier. The Philadelphia-based Franklin Institute's new exhibit, Your Brain, features a striking 3D printed model of the white matter tracts of the human brain. White matter tracts are the pathways that nerve cells use to connect to each other inside the brain, and are incredibly complex.   Dr. Jayatri Das, chief bioscientist at The Franklin Institute, incorporated the displays in a new expansion. The model was built from an MRI scan of a real brain and was then printed using the SLS print method from 3D Systems. It shows approximately 2000 tracts. Printing such a delicate structure proved to be quite a challenge and the project was turned down by several 3D printing bureaus before it was accepted by an outfit in Oklahoma. The model was printed in 10 separate parts and then assembled.   This is truly an amazing advance in anatomic visualization. It's truly beautiful - a piece of art. For updates on news and new blog entries, follow us on Twitter at @Embodi3D. Source and images: 3D Systems

Dr. Mike

Dr. Mike

 

Capillaries in 3D printed organs - a big step towards 3D printable artificial organs.

There has been a lot of hype recently about 3D printed organs. There have been several instances in recent memory where somebody holds up a kidney or liver shaped 3D printed blob of jello-like cells and the press goes wild, as if the jello blob, because it is shaped like an organ, must be an organ and is ready to go directly into a patient. As someone who works with transplant patients all the time I can tell you it's not that simple. Real organs are incredibly complex. Take the liver for example. On the microscopic level there is a meshwork of cells comprised of reticuloendothelial cells. Hepatocytes live within this meshwork. Endothelial cells line small spaces called sinusoids. All these structures are connected to microscopic bile ducts, arterioles, and veins. The picture below demonstrates the microscopic architecture. The point is that an organ is more than a mass of cells. There is very, very complex microscopic and macroscopic architecture. That's why a recent research paper by a multinational team of investigators is so interesting. Reported in the journal Lab on a Chip, researchers from Australia, Italy, Korea, Saudi Arabia, and American teams at Harvard, Stanford, and MIT, report being able to 3D print capillaries. Additionally, they were able to grow "endothelial monolayers," which basically means a layer of cells that comprise the normal lining of capillaries in the body. An endothelium is important, because without it the blood within the capillaries will clot, leading to tissue death from lack of blood flow.   In theory this advance means that artificial organs with complex microscopic architecture, which is essential for a real organ to function, can be 3D printed. If the artificial organ is also manufactured using cells from the patient, this will eliminate the two greatest problems with modern organ transplantation. These are 1) insufficient number of transplantable organs (in the US they need to be harvested from recently deceased individuals who donate them, and there just aren't enough), and 2) immune rejection of the organ when the body inevitably realizes that the organ is from a different person. External video demonstrating advances in 3D Printing and bioprinting   This reminds me of an episode of Star Trek when Captain Picard is impaled through the heart and the laughs when he sees the dagger protruding from his chest. He is saved by a heart transplant. Perhaps he is laughing because in the Star Trek future an artificial heart with accurate microarchitecture is probably as close as the nearest replicator. Given this latest research, maybe someday soon we will all feel comfortable about rumbling with a gang of Nausicaans, knowing we can get spare organs whenever we need them.   For updates on news and new blog entries, follow us on Twitter at @Embodi3D.

Dr. Mike

Dr. Mike

 

3D printing prosthetic arms for children who are missing theirs

E-Nabling the Future is a volunteer organization dedicated to creating inexpensive 3D printable prosthetic hands and arms for children around the globe who are missing limbs. The movement has grown from an informal collaboration to a veritable movement, and they are now producing functional and inexpensive prosthetic limbs. Traditionally designed arm and hand prostheses can cost up to $40,000. According to 3Dprint.com, it is now possible to create an entire functional my electric arm for $350. Their most recent innovation uses electrical impulses from the bicep muscle to open and close the hand. This enabled a six-year-old boy named Alex who is missing his right arm to give his mother a big hug.                           The picture of Alex's myoelectric prosthetic right hand gave me a sense of déjà vu -- I swear I had seen something like this before. Then it hit me. The prosthetic is eerily similar to Luke's prosthetic hand in The Empire Strikes Back. Thanks to the volunteers at E-Nabling the Future, science fiction is becoming science fact, and children are the beneficiaries of this amazing movement.     Please check out the E-Nabling the Future website, and if you are so inclined give a donation to this worthy cause. For updates on news and new blog entries, follow us on Twitter at @Embodi3D. Select images by Kt Crabb Photography

Dr. Mike

Dr. Mike

 

3D Printable Lace Skull, Free for Download.

I've been working on ways to artistically expand on 3D printed anatomic models beyond an exact replica of the anatomy. My first project is this Lace Skull. The skull is based on an anatomically accurate skull generated from a CT scan. I have made several of the earlier skull models available for download on the Embodi3D website here and here. Using a variety of methods, I have transformed the skull and given it a unique lace-like appearance. The overall surface contours are still anatomically accurate. The lace-like texture gives the model its unique aesthetic but also cuts down on printing material while maintaining mechanical strength.   I have made the STL files available for FREE download in the File Vault section of the Embodi3D website. You can find the STL files here (HALF-SIZE | FULL-SIZE). If you 3D print this file, please report back regarding your outcome. I printed a half-size model using the "White, Strong & Flexible" nylon material on Shapeways.   If you would rather have Shapeways print the model and ship it to you for a fee, you can go Shapeways to directly order the models here (HALF-SIZE | FULL-SIZE).   I hope you enjoy this 3D printable model. Please report back on your experiences with printing the model. Also, please share your own 3D printable creations with the community in the File Vault section of the website.          

Dr. Mike

Dr. Mike

 

Member success with 3D Printed Skull

Community member Mike Kessler has successfully printed a half skull available for download in the File Vault using a filament printer. He made the skull to help a family member who is learning skull anatomy in medical school. The skull looks great. Fantastic job Mike! Check out Mike's complete album here. If you have had success with printing one of the 3D anatomic models available for download on the site, please let us know how things went. If you are creating your own medical 3D models, please share them with the community in the File Vault.

Dr. Mike

Dr. Mike

 

3D Printable Human Heart Model

Lately I've been working on creating a 3D printed human heart from a CT scan. Printing cardiovascular structures like the heart is more difficult than bony structures since the blood vessels are usually not well visualized without a CT scan that uses intravenous contrast. Furthermore, the heart is always moving, and special techniques need to be performed during the scan to generate high-quality images that are free from motion artifact. This is one of several models I've been working on. I haven't yet tried 3D print this model, but I thought I would share it with the community to see what people think. The STL file can be downloaded here. If you 3D print this model, please share your results with the community. Post an update or upload pictures of your printed model. If you are creating your own 3D printable models, please consider sharing them with the community in the File Vault. On another note, I am considering putting together some video tutorials on how to create 3D printed anatomic models from CT scans using freeware. If you are interested in seeing tutorials like this, please leave a comment. Happy printing!            

Dr. Mike

Dr. Mike

 

Maker Profile: Dr. Marco Vettorello

Dr. Marco Vettorello is an anesthesiologist and intensive care physician in Italy. On the side he has been creating high quality anatomical models that are of great value for medical education. He has agreed to share his models with the Embodi3D community. All are available for free download. The models that he has shared include: Human heart Anatomic skull Maxillary bone Frontal bone Mandible Sphenoid bone             Thanks very much Dr. Vettorello! We appreciate you sharing with the Embodi3D community!        

Dr. Mike

Dr. Mike

 

Revealing the Beauty of the Microscopic World Through 3D Printing

There is tremendous beauty and diversity in nature that goes unnoticed by humans because it is simply too small for us to see and appreciate. Embodi3D member Michael Holland hopes to change that. Via his eponymous company Michael Holland Productions, he has created a fascinating traveling museum exhibit called MacroMicro that reveals the striking complexity and beauty of the microscopic world through high-resolution micro-CT scanning and 3D printing. On the remote island of Iriomote-jima, part of the Okinawa Islands of southern Japan, beautiful white sand beaches can be found. Closer inspection of the sand reveals that each grain has a star-shaped appearance. These white sand grains are primarily the skeletons of Baculogypsina sphaerulata, tiny marine organisms that produce an intricately detailed star-shaped calcium carbonate shell. These beautifully complex structures go completely unnoticed by the average beachgoer. But through use of high-definition microscopic CT scanning and 3D printing, these sand-like shells, when enlarged as big as a dinner plate, come alive. Star sand The Humboldt squid, also known as jumbo squid, is a large squid with a mantle length that reaches up to 1.5 meters in length. Living in the eastern Pacific Ocean off the coasts of North and South America, these predatory invertebrates entrap their prey with tentacles that bear up to 200 suckers each. These predators have a devious secret. Within each sucker is a ring filled with serrated dagger-like spines. Once enveloped by the tentacles, hundreds of suckers attach to the helpless prey, and thousands of these tiny dagger-like structures penetrate it, ensuring that even the slipperiest of prey meets its inevitable doom. Enlarged to the size of a basketball and 3D printed (lead image, shown above), once can see how nasty this adaptation truly is. Everything we hear -- beautiful music, the rustling of leaves, a loved one's laughter -- is made possible by the incus, malleus, and stapes. These three tiny bones are the smallest in the human body and form the basis of the middle ear, without which human hearing would not be possible. Noise around us causes our tympanic membrane, or eardrum, to vibrate. But how are these vibrations transmitted to our brains where we process sound information? This is where the incus, malleus, and stapes come in. Attached to the inner surface of the eardrum, these bones form a chain that transmits the vibratory motion to the inner ear. There, tiny hairs are disturbed, which sends an impulse through the auditory nerve to the brain, which we interpret as sound. Everything we hear is transmitted as vibrations through these three tiny bones, called the auditory ossicles. In Latin, the malleus, incus, and stapes mean the hammer, anvil, and stirrup, respectively. When enlarged to the size of a real hammer through 3D printing, you can see how these tiny bones got their names. auditory ossicles of the ear The innocuous Townsend's mole, Scapanus townsendii, is commonly found in the moist soils of the Northwestern North American coastline. It's short and stubby arms are perfectly designed for digging, a fortunate thing as it spends most of its time searching for earthworms and other food in shallow burrows. However, when its small size is accounted for, the mole's arms are massively powerful. Click on the video link below to hear Michael talk about this small furry Hercules and how its secrets are revealed through 3D printing.   The Townsend's mole Through his MacroMicro exhibit and 3D printing, Michael is bringing the striking beauty of the microscopic world to us. Look for his MacroMicro exhibit in a museum near you beginning in 2016. The MacroMicro exhibit

Dr. Mike

Dr. Mike

 

Using 3D Printed Liver Models for Guidance During Liver Surgery

Researchers from Nagoya University in Japan are now using customized 3D printed liver models created from patient Computer Tomography (CT) scans for guidance during liver surgery, as reported at the 2014 Radiological Society of North America meeting. The human liver is a complex organ. Liver cells, called hepatocytes, do the work of cleaning the blood of toxins and waste -- the primary function of the liver. Hepatocytes are dependent on a complex network of vascular structures, including bile ducts, hepatic arteries, hepatic veins, and portal veins, which are organized into a complex branching network. This network is in turn organized into self contained units, each with its own bile ducts, arteries, and hepatic and portal veins, called segments, of which there are eight in the typical human liver.   When liver surgeons resect, or cut out, cancer from the liver, they remove the entire segment or segments that are involved, working hard to avoid any damage to segments that are uninvolved. The procedure is delicate, and there is no room for error. Cut out too little and there may be tumor left in the liver which can subsequently spread. Cut too much and a host of complications can arise, including bleeding, bile leak, liver failure, and potentially death. Furthermore, the surgeon must work under conditions where the tumor and vital structures may be poorly visualized or obscured by blood in the operative field.   This is where the 3D printed models come in. The Japanese researchers took CT scan data from the patient undergoing the liver cancer surgery and created a 3D printed model of the entire liver using a transparent material. They left the vascular structures hollow, and subsequently filled them with a colored material to color-code each type of vessel. The model was then vacuum sealed in a sterile pouch and brought unto the operating room during the surgery. The surgeon could handle the 3D model during the operation. Before making each cut, the surgeon could refer to the model and confirm where the tumor and each vital vessel was located, thus avoiding mistakes and reducing operating time.   Creating 3D printed models prior to surgery for preoperative planning and intraoperative guidance is something that I have done personally for endovascular procedures (a publication on my experience is forthcoming). I can tell you that the certainty of knowing what you are getting into, and avoiding nasty and unexpected surprises in the OR, is invaluable. Once surgeons experience the comfort of having an anatomically accurate intraoperative 3D printed reference model they will never want to go back. 3D printing in medicine is here to stay.             3D printed liver model showing the tumor to be resected. 3D printed liver model I will be publishing more blog articles about 3D printing at the 2014 RSNA meeting. Follow this blog or follow on Twitter @Embodi3D.

Dr. Mike

Dr. Mike

 

Amazing 3D Printed Models on Display at RSNA 2014

3D printing is a hot topic at this year's Radiological Society of North America (RSNA) meeting in Chicago. I've been involved in medical 3D printing for the past two years, and every month there seems to be more interest. At this year's RSNA meeting, the level of interest is higher than I have ever seen before. There are literally dozens of sessions related to 3D printing in radiology, and they all seem to be very well attended. The Sunday session on "Fundamentals of 3D Printing" had a line out the door and down the hall as shown by the picture below. So many people were standing in the room that they had to close the session due to fire safety limits.   Perhaps one of the biggest draws is the vast array of striking 3D printed models on display from a variety of vendors that offer 3D printing and consulting services. 3D printer manufacturers have been working hard on new and exciting 3D printing materials. As a result, there is now a large selection of materials to choose from, each with a unique set of properties. When the right anatomy, materials, and printers are combined effectively, the models can truly become things of beauty. While you can't get your hands on the individual models shown here, Embodi3D does maintain a growing library of 3D printable models for you to download and 3D print yourself. I will put links to some of my favorite downloadable files at the end of this article.             Long lines were seen outside of most 3D printing sessions, including this one on Sunday morning. In this hands-on session which teaches 3D printing software, each of 50 workstations was occupied. There was standing room only in the back of the room. 3D printed model of a kidney with a tumor and blood vessels (pink). This model uses two colors to highlight anatomy. 3D Systems Medical Modeling 3D printed model using colored gypsum powder shows the various structures of the heart. 3D Systems Medical Modeling A human brain. 3D Systems Medical Modeling 3D model of a spine with severe deformity. 3D Systems Medical Modeling Multicolor 3D model of the skull, with cut away that shows the cerebral arteries (red) and veins (blue). 3D Systems Medical Modeling Hollow model of an abdominal aortic aneurysm using two colors. The atherosclerotic calcium is shown in pink. 3D Systems Medical Modeling This large model of a skull and mandible was designed to demonstrate jaw alignment. 3D Systems Medical Modeling This transparent brain shows various white matter fiber tracks in different colors, an amazing property of newer 3D printing materials. Stratasys. Multicolor 3D print of a heart. Stratasys 3D print of heart with detailed pulmonary arteries and veins. Stratasys 3D print of a skull using transparent material. Materialise Example of 3D printed orthopedic surgery cutting guides used for knee replacement surgery. Materialise Glass-like 3D print of a pediatric heart. Materialise. Select 3D Printable files available for free download on Embodi3D.com. Must register to download. Registration is free and only takes a minute. Human brain Human heart #1     Human heart #2 Half skull, sagittal cut Skull base "Lace" skull     Lumbar vertebra

Dr. Mike

Dr. Mike

 

Invasive Heart Surgery Avoided as Advances in 3D Printing Improve Safety of Transcatheter Aortic Valve Replacement (TAVR)

3D printing is revolutionizing the treatment of aortic stenosis, as reported by researchers from St. Joseph's Hospital in Phoenix, Arizona and presented at the 2014 Radiological Society of North American (RSNA) meeting. Aortic stenosis is a deadly condition where the valve that connects the heart to the aorta does not open properly. The aortic valve, as it is called, is designed to open freely to allow blood pumped from the heart to move in a forward direction into the aorta, the main artery of the body. At the end of a heart contraction, the valve closes to prevent the blood from flowing backwards. In patients with aortic stenosis, the valve fails to open during contraction, thus preventing blood from flowing forward during cardiac contraction (systole). The heart compensates by squeezing harder and harder to maintain adequate forward flow. Eventually, the heart becomes too strained and a variety of severe complications can ensure, including heart attack, heart failure, syncope (fainting), and sudden death. In patients with severe aortic stenosis there is a 50% chance of dying within two years if untreated. Traditional treatment of aortic stenosis involved open heart surgery to replace the valve. This is a major operation and involves sawing through the breast bone to open the chest and gain access to the heart. As one can imagine, the procedure is risky and recovery takes a long time. Many patients who are too ill or weak and are not eligible for the surgery. Fortunately, there is a new procedure where a prosthetic aortic valve can be implanted by navigating a plastic tube, or catheter, to the heart through a puncture in the artery of the hip or sometimes via a direct puncture through the apex of the heart. This procedure, called a Transcatheter Aortic Valve Replacement, or TAVR, promises to make aortic valve replacement minimally invasive, that is doable through a small hole instead of requiring open surgery. Recovery time is significantly less and patients who are ineligible for conventional surgery can often get TAVR. The major problem with TAVR is that it can be very difficult to accurately place the prosthetic valve through the catheter, and poor placement can result in devastating consequences. Unlike open surgery, where the surgeon has direct access to the diseased heart valve, with TAVR the physician must work through the catheter. The valve is loaded on a collapsed metal mesh called a stent. The stent is then inched forward through the catheter into the proper position. The position is checked with x-ray and then the stent is expanded -- hopefully in the correct position relative to the diseased aortic valve, pushing it aside and replacing it with the new prosthetic valve. Once the prosthetic valve is expanded it cannot be retrieved or repositioned, and millimeters matter. Valves come in different sizes. If the valve is the wrong size or malpositioned by even a few millimeters it can cover the coronary arteries and lead to heart attack, cause blood clots to form leading to stroke, or even come free and cause tearing of the aorta. Different sized TAVR aortic valves This is where 3D printing comes in. The Arizona researchers used contrast enhanced computed tomography (CT) scans to gather precise data on the anatomical structure of the heart, aorta, and aortic valve from three patients with severe aortic stenosis, and manufactured precise 3D printed replicas of the aortas. Then they tested various valve sizes and position to see what had the best anatomic fit. They then did CT scans of the prosthetic valves within the 3D models and compared those to postoperative CT scans of the actual patients after TAVR, and found that the pre-surgical test fitting in the 3D printed models accurately predicted how the valves would perform in real patients. Use of the 3D printed models helped the surgeons choose the correct size valve and positioning prior to the surgery, thus reducing the risk of he TAVR procedure. Digital rendering of the aorta Testing the implantable valve in the 3D printed model by deploying it through a catheter (blue) I have personally used customized 3D printed models I designed to test wires and catheters prior to complex mesenteric artery aneurysm treatments (publication forthcoming), and I can tell you that knowing your wires and catheters will work before the procedure is far better than figuring it out with trial and error during the procedure. Presurgical testing with 3D printed models is here to stay. If you are interested in learning more about applications of 3D printing in medicine or how to make your own 3D models, please register as a member (it's free and only takes a minute!) and join the community of medical professionals who are all trying to build the future of 3D printing in medicine. Ask a question, start a discussion, or download free 3D printable models to make on your own. I will put some links to a few of the free downloadable models related to this article below. FREE 3D PRINTABLE DOWNLOADS Heart and pulmonary artery tree http://www.embodi3d.com/files/file/59-heart-and-pulmonary-artery-tree-from-ct-angiogram/ Human heart http://www.embodi3d.com/files/file/27-human-heart/ Human heart #2 http://www.embodi3d.com/files/file/35-3d-printable-human-heart/

Dr. Mike

Dr. Mike

 

Preparing CT scans for 3D printing. Cleaning and repairing STL file mesh from bones using Blender, an advanced tutorial

Summary: This is an advanced tutorial and assumes that you already know how to create STL files from CT scans. If you do not yet know how to do this, stay tuned, as a series of tutorials is planned on this website. Here we will use a free, open-source software package Blender to repair and correct a bony pelvis and lumbar spine model generated from a CT scan. If you would like to follow along with this tutorial, you can download the relevant Blender and STL files here, and follow along. >>DOWNLOAD THE TUTORIAL FILES AND FOLLOW ALONG.<< UPDATE: If you have very extensive mesh errors in your model, you can read my other medical 3D printing tutorial on how to repair mesh errors quickly using Blender. You can watch the YouTube video for a high-yield introduction, but also read this page for additional details.   Background on the Problem Before we dive in, let's take a moment to discuss what the medullary cavity of a bone is and why it's a problem if you're trying to 3D print bone models made from a CT scan. Bones are not solid, even though they may appear to be so. Most bones have a very hard, very dense outer layer comprised of cortical bone. This tough outer part of the bone is very hard and is what gives bones their strength. The inner core of most bones contains fatty bone marrow, and is made of much softer bone that is less dense, called spongy bone. On a CT scan you can see these two different types of bone. Take this CT scan of the pelvis, for example. Figure 1 In the CT scan image shown in Figure 1, the hard, dense cortical bone is seen as a bright white outer surface of these pelvic bones. The white color indicates that it is very dense. The spongy bone, which is less dense and contains fatty bone marrow, can be seen in the center of the iliac bones and sacrum on this image. This type of bone is not white, but is a grayish color on a CT scan image. In some areas it is approaching black in color, which means is not very dense at all. Outside the bone we can see muscle represented by this light gray color, and intra-abdominal fat which is represented by this dark gray color. Figure 2 If we measure the density of these bones in Hounsfield units, which is the unit of density that is measured on a CT scan, we can see that the dense cortical part of the iliac bone in this image measures 768 Hounsfield units, and is shown in the rightmost red circle (Figure 2). The less dense medullary bone within the sacrum measures 1.7 Hounsfield units, as shown within the red circle in the middle. If we measure the muscle in the gluteus maximus area, this measures 51 Hounsfield units, as shown in the red circle on the left. So in this case the medullary bone is actually less dense then muscle around it. How can bone be less dense than muscle? Because it is filled with fatty bone marrow. Remember, fat floats on water, and is thus less dense than water. (What also floats on water? A duck. But that is another story...) In Figure 2, the green circles represent the area of interest that is being measured. The text and red circles represent the measurements for the those areas of interest. The fact that medullary bone and bone marrow is not dense causes a problem when we are trying to convert CT scan data into a digital model that is 3D printable. This is because algorithms designed to select the bone from all the other stuff in the body, such as fat, muscle, air, etc), use density as a means to identify the bones. Here's an example of the 3D model of the pelvis and lumbar spine created from the CT scan we were just looking at. If you look closely at Figure 3 you can see there's a lot of internal geometry within the bones that is not desired (red circles). This extra geometry can cause problems when the file is sent to 3D printer or 3D printing service. The model may be rejected because of characteristics of this internal medullary space, for example there may be thin walls and automated quality checkers may flag the model as unprintable. Furthermore, if you try to perform certain manipulations on the mesh, such as Boolean operators, this unwanted mesh may cause these operations to fail. If we want to 3D print our bone models, it is best to get rid of extraneous and unwanted mesh. Figure 3 Getting started on cleaning your mesh in preparation for 3D printing. 1) Start by importing your STL file into Blender. If you don't have Blender, it is available for free at http://www.blender.org. Blender is available in Windows, Macintosh, and Linux versions. Be forewarned. Although Blender is powerful, it takes a little bit of time to get used to it. Be patient. Open Blender and select File -> Import -> Stl (stl) as shown in Figure 4. If you are following along with this tutorial using the tutorial files, select the "Pelvis and Lumbar spine, uncleaned.stl" file. Figure 4 You will find that the mesh appears quite large. This is because Blender uses an arbitrary unit of measure for distance called a Blender Unit. The way that STL files are interpreted, one Blender unit is equivalent to 1 mm, thus the model appears quite large. Use the scroll wheel on your mouse to zoom out. If you want, you can re-size your mesh by hitting the S key. You may also find that your mesh appears clipped, as shown in Figure 5. This is because by default Blender uses a clipping distance of 1000 by default for the view, clipping any objects in the scene too far from the camera. This is easily fixed. View the Properties bar by clicking the "+" in the upper right corner, as shown by the red circle in Figure 5. Or, you can type N to show the Properties panel. Then under View, type 100,000 in the Clip: End field, as shown in Figure 6. Figure 5 Figure 6 2) To identify where you have extraneous mesh, you must first go to Edit mode. Before doing this, make sure you have selected your model by right clicking it. The model should be surrounded by a yellow halo, which indicates that it is selected, as shown in Figure 7. Figure 7 Enter Edit mode by hitting the Tab key, or by selecting Edit mode from the Mode button, located on the bottom left toolbar, as shown in Figure 8. Use the Z key to toggle between types of viewport shading. You can also use the viewport shading button in the bottom toolbar as shown in Figure 9. Select Wireframe viewport shading. Figure 8 Figure 9 3) Use the scroll wheel to zoom in and out, and the middle button to pan about. Zoom into the L3 vertebral body (3rd lumbar vertebral body. If you need a refresher on lumbar anatomy, check out Wikipedia). As was shown in Figure 3, there is excessive mesh in the medullary cavity of the bone that is persistent within the model. We want to remove it. How this extra mesh got here has to do with the original CT scan and how the surface STL model is generated from CT scan data. If you look at the original CT scan of this vertebral body, as shown in Figure 10, you can see very small perforating holes within the posterior part of the vertebral body, as shown by the red arrows. These are nutrient foramina. They are tiny holes in the bone that allow arteries to penetrate through the thick outer cortex and into the medullary cavity, supplying blood to the bone marrow. When the surface generating algorithm creates the STL file from the CT scan, it finds its way from the surface into the nutrient foramina and maps the internal medullary cavity of the bone. Essentially, the algorithm determines that the bone is hollow, and has a connecting tunnel between the surface and the hollow interior, as shown in Figure 11. This is actually true, but for the purposes of 3D printing we are not interested in extremely complex geometries within the medullary cavities of the bone. For practical purposes of 3D printing we wish the bones to be solid, even though in nature they are not. Figure 10 Figure 11 4) The easiest way to delete the medullary mesh is to identify where the mesh is connected to the surface via these nutrient foramina. To do this, inspect the mesh carefully using Wireframe viewport shading, which should give you an idea of where these connecting tunnels are located. Once you have identified the area, use the lasso tool by holding down the CTRL key and left clicking a loop around the area of interest, as shown in Figure 12. You must be in Wireframe viewport shading in order to make the selection. If you are in Solid viewport shading, you will only select the surface elements. Also, make sure you are in vertex selection mode. The three selection modes (Vertex, Edge, Face) are shown circled in red on the bottom toolbar in Figure 12. Figure 12 5) Once you have selected the mesh elements of interest, you will hide the non-selected mesh elements. This simplifies your view and also reduces the processing time needed by the computer to display the image to you in real time. With large data sets, such as those collected by CT scans, even a powerful desktop system can become very sluggish when the entire mesh is displayed and manipulated at once during editing. Hiding temporarily unneeded mesh saves a lot of time. 6) With your mesh elements of interest selected in orange as shown in Figure 12, hold down the control key and hit the "I" button. This inverts the selection, as shown in Figure 13. Next, hide the selected mesh by hitting the "H" key. You should now have a very limited amount of mesh displayed, as shown in Figure 14. Figure 13 Figure 14 Rotate the mesh to a different orientation and then select your target mesh, invert the selection, and hide the inverted selection again. At this point you should have a very small amount of mesh that you are focusing on, such as that shown in Figure 15. Figure 15 7) Now that your visible mesh is small enough to work with, switch back to Solid viewport shading using the viewport shading box in the lower toolbar, or by hitting the "Z" key. Zoom in and identify where the nutrient foramina are present on the surface of the bone. Go to face selection mode using the face selection button on the bottom mouth bar or by hitting CTRL-TAB-3. Using the right mouse button to select a face near the opening of the nutrient foramen. Using the CTRL key and right mouse button, select a loop of face is completely around the foramen, as shown in Figure 16. Make sure you select an entire loop of faces around the hole. You want to complete cut it away from the surface. Figure 16 Now delete this selection. Hit the delete key, and select Faces (or hit the delete key followed by the F key). You should now have a hole in your mesh, and the tunnel between the surface and the medullary mesh has been cut completely. Double check to make sure there are no stray edges or face still connecting the two parts. 8) Now we are going to close the hole. Go to Edge the selection mode using the button in the lower toolbar or by hitting CTRL-TAB-2. Holding down the ALT key, right-click on one of the edges abutting the hole. Blender should select the entire circumference of the hole, as shown in Figure 17. Next, fill in a face using the F key. A face should appear. Convert this face to triangles by hitting CTRL-T. if you want to smooth out the mesh, you can take an extra step and apply local smoothing by hitting W followed by O. Your hole should be filled in and smoothed, as shown in Figure 18. Figure 17 Figure 18 Repeat steps 6 through 8 for each nutrient foramen tunnel connecting the surface to the medullary cavity. 9) When you have finished making all the edits to your viewable mesh, it is time to unhide the hidden mesh that comprises the bulk of your model. Hit Alt-H to unhide all the hidden mesh. Most of it will be selected. Hit the A key to unselect all. The A key toggles between select all and select none. 10) Once you have determined that all tunnels between the surface and medullary cavity have been deleted and filled, it is time to delete the entire block of medullary mesh in one operation. Make sure you are in edit mode, with wireframe viewport shading. Using the right mouse button, select a vertex from the medullary block mesh, as shown in Figure 19. Figure 19 We are now going to select every vertex that is connected to this single vertex. Because the entire medullary mesh is disconnected from the rest of the model, the remainder of the model should not be selected. Hit the CTRL-L key to select all contiguous vertices. You should find that only the unwanted medullary mesh is selected, as shown in Figure 20. Hit the delete key, followed by "V" for vertices, and the entire block of unwanted medullary mesh will be deleted at once. Wow! That was gratifying! After all that work you have probably deleted several thousand unwanted vertices in one swoop. Figure 20 Figure 21 Your target bone, in this case L3 -- the third lumbar vertebra -- should now be free of unwanted medullary cavity mesh. You can repeat this process for each medullary cavity in your model. In the particular model that accompanies this tutorial, that would be L4, the bilateral iliac boness, sacrum, and a few other places. It can be a time-consuming process, but with practice even a complex model with tens of thousands, or millions of faces can be cleaned in a few hours. I hope you found this tutorial helpful. If you have questions, please leave a comment below. If you are making 3D anatomic models from medical scan data, please consider sharing your creations with the Embodi3D community. Embodi3d is a community of biomedical 3D printing enthusiasts. We are all trying to help each other, and by sharing your models you can contribute greatly to the community. Here are a few examples of 3D printable anatomic models Embodi3D members have shared for free. Please share too! Human heart Human male skull Lace Skull Tweet ⇒ http://goo.gl/xuvTiv ⇐ Post to FB⇒ http://goo.gl/Ns8MuI ⇐ Twitter: https://twitter.com/Embodi3D FB: https://www.facebook.com/embodi3d LinkedIn: https://www.linkedin.com/company/embodi3d YouTube: http://goo.gl/O7oZ2q

Dr. Mike

Dr. Mike

 

Saving a Spleen with 3D Printing: Pre-Surgical Planning with Medical Models make "Impossible" Surgeries Possible.

Summary: 3D printing is making rapid advances in many areas of medical treatment. In this article, I'll describe how I used recent advances in 3D printing to save a patient from having to have her spleen removed. In the process I broke some new ground in use of 3D printing in surgical planning. The clinical case and 3D printing advances are described in a recently published peer-reviewed paper in the medical journal Diagnostic and Interventional Radiology.   Intro image: The author using 3D printed vascular models in the OR.   A clinical conundrum
I am a board-certified interventional radiologist, and specialize in the minimally-invasive treatment of vascular (involving blood vessels) disorders. My adventure in 3D printing started when a very nice 62-year-old lady was referred to me by another doctor. A CT scan done for another reason had incidentally detected aneurysms in her splenic artery. The splenic artery is the major artery going to the spleen. An aneurysm is a bulging of the artery wall. Aneurysms are dangerous because as they grow they stretch the artery wall, causing it to thin. Like a balloon, the more the aneurysm stretches, the thinner the artery wall becomes, until the wall is too thin to hold back the pressure of the blood and the aneurysm bursts. This can lead to sudden, acute, life-threatening internal bleeding.  
Figure 1. Examples of aneurysms. The thin, stretched out walls of the aneurysm predispose it to rupture. The larger the aneurysm, the greater the risk of rupture and bleeding. Source Drugline.org.   Medical convention states that when a splenic artery aneurysm is 2 cm or larger, it is at risk for rupture and should be treated. My patient had two aneurysms in her splenic artery, each of which was 2 cm in size. Something needed to be done. A third, smaller aneurysm was also present but it didn't need to be treated at this time. The conventional treatment in this situation is a surgical splenectomy, in which a surgeon, either in an open fashion or laparoscopically, physically removes the splenic artery with its aneurysms. Because the spleen cannot survive without its artery, it must be taken out too. The spleen plays a critical role in the body's ability to fight infections, so after removal of the spleen, patients are at higher risk for certain infections.    
Video 1. Digital rendering showing the two large splenic artery aneurysms arising from the splenic artery. The aneurysm are the sphere-like bulges arising from a small artery in the middle of the aorta. The large trunk is the abdominal aorta. Rendering done with Blender.   An alternative treatment to surgical removal is splenic artery embolization. In this procedure, a vascular surgeon or interventional radiologist, such as myself, will make a needle puncture in the artery of the hip and navigate a small plastic tube, called a catheter, into the splenic artery using x-ray guidance. A series of small metallic threads, called coils because they coil up once deployed, are then pushed through the catheter into the splenic artery, where they plug up the entire artery. In principle, the technique is similar to putting hair down your bathroom drain. The hair takes up space and eventually plugs the pipe. In the same way, fine thread-like platinum coils can be pushed into the artery one at a time until the artery is plugged up. Any blood in the artery clots, and without any blood flow there is no pressure on the aneurysm wall and thus no risk of the aneurysms rupturing. Unfortunately, the lack of blood flow also causes the spleen to die from insufficient oxygen. The process of the spleen dying from lack of blood flow results in pain for a day or two. Also, without a functional spleen, these patients also are at higher risk for infections.   My patient was a very intelligent and determined individual. I explained both options to her in detail, but she would not accept either of the conventional treatments. She did not want to lose her spleen and be at increased risk of future infections. She challenged me to find a way to treat her aneurysms while saving her spleen. I reviewed the case and imaging studies with several of my colleagues, all board-certified specialists in treating this type of problem. Everybody said the spleen couldn't be saved. It was "impossible." She either had to have her spleen removed or her splenic artery embolized. Do nothing and it was just a matter of time until an aneurysm ruptured, probably killing her. I was greatly moved by my patient's doggedness. She wasn't willing to accept the limits of conventional medical treatment, so I didn't think I should either. I kept searching for solutions.   I was aware of some specialized catheter equipment that had been specifically designed to treat aneurysms in the brain. Brain aneurysm treatments are very delicate affairs. If an aneurysm in the brain ruptures, it can result in intracranial bleeding, stroke, permanent disability, or death. Brain aneurysms can be treated with placement of metallic coils through a catheter, as long as the coils are only placed in the bulging, aneurysmal part of the artery. There, they cause blood to clot in the aneurysm, which reduces pressure on the aneurysm wall and prevents it from rupturing. These special coils and catheters are designed to treat the aneurysm while preserving blood flow in the parent artery. Because these aneurysms are in the brain, any disruption in the blood flow of the parent artery will result in stroke.  
Figure 2: How coils can be used to treat aneurysms in the brain. Using specialized equipment designed for the brain, coils are used to pack the aneurysm while preserving blood flow in the parent artery. (Image source: wix.com)   Could the specialized coils and catheters designed to treat aneurysms in the brain work in the splenic artery? Nobody seemed to know. The patient's splenic artery had an unusually large number of loops, which would complicate any procedure. A search of the published medical literature did not produce any useful results. There were many variables that were different. I discussed my thoughts with the patient. I thought there might be a way to treat her aneurysms while sparing her spleen using this specialized brain aneurysm equipment. But the only way to know if the equipment would work would be to try it during an actual procedure. She gave me a puzzled look. "Well isn't there a way for you to practice?," she said.   For generations doctors faced with difficult and complex surgical procedures have really had only one true way to know if they will work: try it in a real surgery. We do everything possible to maximize our chance of success, such as ordering scans, consulting colleagues, reading research articles, and imagining the procedure over and over again in our heads. We try to know everything possible about the intended surgical procedure beforehand. But, the only way to truly know how things will go is to actually do it. There really wasn't any way to know how the brain catheter equipment would work in the spleen because nobody had ever done a procedure quite like this before. Yet, I kept thinking about my patient's statement. Why wasn't there a way for me to practice this beforehand?   Finding a solution with 3D printing
At that point I had been looking into uses for 3D printing in medicine for about a year. There seemed to be great potential, but at the time few people were using 3D printing in real patient care. I had designed a few simple 3D printable body parts from medical imaging scans. Would it be possible to 3D print a replica of my patient's splenic artery, and practice doing this complex procedure in the 3D printed model? I had never 3D printed an arterial structure of such complexity. Another search of the medical literature revealed that nobody else had either. I was further hampered by the fact that as a private practice doctor, I don't have access to an expensive 3D printer or the costly proprietary software that is needed to create complex 3D printable anatomic models. Nobody was paying me for my time or expenses. I needed to find a solution that was practical but inexpensive.   I invested hundreds of hours testing free and open source software packages to see if they could be used to generate the detailed 3D printed splenic artery model I needed. I eventually found that a combination of the software packages Osirix and Blender, the latter of which is typically used for computer animation, would allow me to design a detailed anatomic model from my patient's CT scan. I could then use the low-cost online 3D printing services Shapeways and iMaterialise to actually print my models. I paid for everything out-of-pocket. When the models arrived in the mail I couldn't believe it. They were precise full-scale replicas of the patient's splenic artery.  
Figure 3: A precise 3D printed replica of the patient's splenic artery.
I contacted representatives from the companies that manufactured the brain aneurysm equipment. They had never heard of anybody testing their equipment in a 3D printed model before, but enthusiastically supported it. They donated real guidewires, catheters, stents, and coils for use in testing. Several came over to my house and we replicated the entire procedure inside the 3D model. During this testing I learned that some of catheters and wires would work well in the complex curves of the patient's splenic artery, and others would not. I was able to get all of the trial and error done in the model, something that otherwise would have taken place during the actual procedure. The model wasn't exactly the same as a real patient, but I was able to learn a lot about how the catheters and wires handled in the complex and unique geometry of the patient's splenic artery.    
Video 2: Time-lapse footage of endovascular wire and catheter testing in the 3D printed model. Numerous problems were encountered with the difficult geometry of the splenic artery, but with trial-and-error a combination of wires and catheters was found that could handle the difficult geometry.   With the optimal set of catheters, wires, stents, and coils preselected, I subsequently did the real procedure on the patient. I completed all the necessary paperwork including getting approval from my hospital's research review board. I brought the 3D models into the operating room as a reference, and referred to them many times during the procedure. All of the preselected equipment worked beautifully, just as it had in testing. I was successful in putting coils in the aneurysms while preserving blood flow to the spleen. Even without having to try out different equipment combinations, the procedure was still very difficult and took five hours. If I hadn't had the ability to practice the procedure in the 3D printed model and preselect my equipment, it easily could have taken twice as long. That is, assuming I didn't collapse from exhaustion and dehydration before finishing it. More importantly, the opportunity to practice the procedure beforehand gave me confidence that I could be safe and successful in doing something that had never been done before. Nearly 2 years after the surgery, the aneurysms no longer a threat and the patient's spleen is fully functioning.  
Figure 4: Referring to the 3D printed models in the OR during the surgical procedure to correct the splenic artery aneurysms.  
Figure 5: positioning a small catheter into the splenic artery via a needle puncture in the arm.   3D Printing Lessons Learned
This experience fundamentally changed my perception about the value of 3D printing in medicine. For safe, easy, and routine medical procedures, 3D printing will probably not have much of an impact in the foreseeable future. It's too time consuming and costly to make 3D printed models. For complicated or high risk procedures, however, it can be invaluable. No doctor wants to take unnecessary risks or have a bad outcome in surgery. Unfortunately, there are many, many unknowns in surgery, particularly with complex and unusual cases. 3D printing an anatomic model before surgery to study and practice reduces those unknown variables, making risky cases much safer. After my experience, I have no doubt that 3D printing will have a significant impact in improving patient care in all fields of medicine.   It is my belief in the potential of 3D printing to help doctors and patients that led me to the creation of this website, Embodi3D.com. Embodi3D is a place where 3D printing enthusiasts can help each other in all fields of biomedical sciences. Members can read medical 3D printing news, ask technical questions in the forums, and even download complete 3D printable medical models from the File Vault. There are several tutorials on how to start 3D printing medical models yourself. Everything on the website is free. I ask only that you give back to the community through comments, advice, and sharing of 3D models, if you are able.   Below are two 3D printable models used in actual testing. You can download the models yourself for free.  
Download the FREE solid, splenic artery aneurysm lumen model. This is the solid model that shows the hollow space inside the artery (the lumen).  
Download the FREE hollow splenic artery aneurysm model. This is the hollow model that the catheters and wires were tested in.   You can read the official peer-reviewed account of this 3D printing advance in the medical research journal Diagnostic and Interventional Radiology here.   If you liked this article, please share it with your friends!
Tweet ⇒ https://goo.gl/cq1IQC ⇐ Post to FB⇒ https://goo.gl/VocYWp ⇐
Twitter: https://twitter.com/Embodi3D
Facebook: https://www.facebook.com/embodi3d
LinkedIn: https://www.linkedin...ompany/embodi3d
YouTube: http://goo.gl/O7oZ2q   Other Free STL Downloads  
A Collection of Free Downloadable STL Skulls for you to 3D print yourself.  
3D printable human heart in stackable slices, shows amazing internal anatomy.  
A Collection of Spine STL files to download and 3D print.

Dr. Mike

Dr. Mike

 

3D Printing a Spine Model to Help a Fellow Doctor with Low Back Pain

I was recently contacted by another doctor who asked if I could help him to create a 3D printed replicate of his spine to visualize pinched nerves in his low back and aid with planning a future back surgery. In order to work this doctor has to stand for long hours while performing surgical procedures. Excruciating low back pain had limited his ability to stand to only 30 minutes. As you can imagine, this means he couldn't work. Things only got worse after he had low back surgery.   A CT scan of his lumbar spine (the low back portion of the spine) was performed. It showed that his fifth lumbar vertebra was partially sacralized. This means it looked more like a sacral vertebra than a lumbar vertebra. Was this causing his problem? On the image slices of the CT scan it was difficult to tell.   How the Spine is Organized
First, a word about the different vertebrae (bones) in the spine. There are four main sections of spinal bones. The seven cervical vertebrae are in the neck and support the head. They are generally small but flexible, and allow rotation of the head. The 12 thoracic vertebrae are in the chest. Their most distinctive characteristic is they all have associated ribs, which make up the rib cage. The five lumbar vertebrae are in the low back. These are large and strong, and designed for supporting lots of weight. They do not have associated ribs. The five sacral vertebrae are in the pelvis. In adults, they are fused together and effectively form a single bone, the sacrum. The coccyx, or tailbone, which is a tiny bone at the bottom end of the vertebral column, can be considered a fifth spinal section. This is the bone that is often injured when you fallen your behind. Figure 1 shows the different sections of the vertebral column.  
Figure 1. Sections of the vertebral column. Source:aimisspine.com   Although the bones of the individual sections of the spine usually have their own unique features, it is not uncommon for vertebrae in one section to have features typically associated with an adjacent section. This is particularly true of the vertebrae that are immediately adjacent to a neighboring section. These hybrids are a mix between both sections, are called transitional vertebrae. Do you recall that only thoracic vertebrae have associated ribs? Occasionally the highest lumbar vertebra, L1, will have tiny ribs attached to it. This is a normal variant and is usually harmless. Radiologists who are interpreting medical scans need to be careful to not confuse an L1 vertebra which may have tiny ribs for the adjacent T12 vertebra which normally has ribs. Similarly, the lowest lumbar vertebra, L5, which is normally unfused, can exhibit fusion. As you recall, fusion is a characteristic of sacral vertebrae.   A Congenital Spine Abnormality
This was the situation with our physician. His lowest lumbar vertebra, L5, has partially fused with S1, the highest sacral vertebra. This condition is congenital. He has had it all his life. The fusion can have the side effect of creating a very narrow bony canal through which the L5 nerve roots can exit the spine. Normally, these nerve roots would have much more space as a large gap would exist between the normally unfused L5 and S1 vertebrae. Was this the problem? The CT scan showed the sacralization of L5, but it was difficult to get a sense for how tight the holes through which the nerves exit, the neural foramina, were. See Figures 2 and 3.     Figure 2: Coronal CT image through the L5 and S1 vertebral bodies. Is this the cause of the problem? It is very difficult to get an intuitive sense of what is going on with these flat image slices.     Figure 3: Image from Figure 2 with the neural foramina marked.   Seeking help through Embodi3D
The doctor contacted me through the Embodi3D website and asked if I could create a 3D model design and 3D print of his lumbar spine to help him and his team of spinal specialists understand his unique anatomy better. Of course, I was happy to help. The CT scan was of high quality and allowed me to extract the bones and metallic spinal fusion implants with little trouble. The individual nerves, however, were very difficult to see even on a high quality CT scan. I had to manually segment them one image at a time, which was a very tedious and time-consuming process. After fusing everything together, I had a very good digital model of the lumbar spine. I created some photorealistic 3D renders to illustrate the key findings.   Figures 4 and 5 show the very tight L5-S1 bony neural foramina. The inter-vertebral disc sits within the gap between the two vertebral bodies, and you can see how a lateral bulge from this disc would significantly pinch these exiting nerve roots.     Figure 4: Right L5 nerve root (yellow) exiting the tight neural foramen caused by the fused L5 and S1 lateral processes.     Figure 5: Left L5 nerve root (yellow) exiting the tight neural foramen caused by the fused L5 and S1 lateral processes.   Additionally, I showed that a bone screw that had been placed during the last surgery had partially exited the L4 vertebral body and was in very close proximity, and probably touching, the adjacent nerve root. Ouch! This can be seen in Figure 6. This may explain why the pain seem to get worse after the last surgery.     Figure 6: Transpedicular orthopedic screw which has partially exited the L4 vertebral body and is in very close proximity or in contact with the right L3 nerve root.   The Final 3D Printed Spine Model
The doctor wanted his spine 3D printed in transparent material, so I used a stereolithographic printer with transparent resin. I printed the spine in two separate parts that could be separated and fit together. When separated, the nerves exiting through the neural foramina can be inspected from inside the spinal canal, which gives an added degree of understanding.   Final pictures of the transparent 3D printed model are shown below.                         I just recently shipped the model to this doctor and don't yet know how his back problems will be resolved. With this 3D printed model in hand however, he will be able to have much more meaningful discussions with his spinal surgeons about the best way to definitively fix his low back problems. I hope that the 3D printed spine model will literally help to get this good doctor back on his feet again.

Dr. Mike

Dr. Mike

 

Free and Open-Source 3D Printing Software at RSNA 2015

If you attended my open-source 3D printing didactic talk or open-source 3D printing workshop at this year's RSNA meeting and are interested in a having a copy of my slides (I have been asked several times), or if you are not at the meeting and are just interested, you can find them here. They are an attached PDFs and links.   Manual for Open-Source 3D printing workshop (PDF)   Other resources to help you get 3D Printing the Embodi3D tutorials page: http://www.embodi3d.com/tutorials.html   Additional specific resources I mentioned in my talk:   3D printing with Osirix (Mac only)   3D printing with Slicer (Windows, Mac, Linux)   5-minute modeling with Slicer     Good luck! Contact me if you need any help.   Dr. Mike Open source software RSNA 2015 v1.1.pdf

Dr. Mike

Dr. Mike

 

How to Upload and Share 3D Printable Files on Embodi3D

If you have a 3D printable file you would like to share with the Embodi3D community the process is very easy.   1) First, get your files ready. STL files are best and have good compatibility with most printers. Make sure your files are of good quality as Embodi3D's file library contains high quality files. If you think you files may have errors in them, you can check them using the Inspector function in MeshMixer. Be sure to compress your files if possible using a compression program like WinZip.   2) Take photographs or screenshots of your model, and have the image files ready to upload.   3) Now we are ready to upload. From anywhere in the Embodi3D site, click on the Marketplace nav menu. Make sure you are logged into your member account.
  4) Click the Upload File button in yellow.
  5) Select a category that most appropriately describes your file.
  6) Upload you files. Click on the "Click to Upload Files" button and navigate to the folder that contains the files you want to upload. Please compress your files using a file format like ZIP beforehand to make downloading easier for users. Uploads are limited to 30 MB in size, so compressing large STL files is important. You can upload a file as large as 100 MB if compression is used.
  7) Upload pictures or screenshots. Click the button and navigate to the folder that contains pictures of your model.
  8) Add details about your files. Put in a descriptive title. This is very important to attract people to your file page. Type in descriptive file tags to help search engines find your files. In the Description section, describe your model. You can even embed youtube links. To include media that you have uploaded to your Gallery click the My Media button. Choose whether you want the file to be free or paid. If you want the file to be a paid file (i.e. downloadable for a fee), see the selling page for more information on how to sell your files. Finally, choose a license type. Free files are distributed with Creative Commons licenses. Choose the one that you like the the best and click "Add Submission."     9) View your newly shared file! Thanks a bunch! By sharing your file you are helping other Embodi3D members with research, education, and a variety of other worthy causes.     If you would like to download the splenic artery aneurysm file shown in this tutorial, you can do so here.

Dr. Mike

Dr. Mike

 

Dr. Mike's Interview on Radbuz

Today I was interviewed and featured on Radbuz. I spoke with Dr. Jenny Chen about my experiences with 3D printing in the biomedical space and where I think the field is going. Check it out! http://radbuz.com/2014/08/24/influencers-an-interview-with-dr-michael-itagaki-embodi3d-com-on-3dprinting-in-healthcare/

Dr. Mike

Dr. Mike

×