Tag Archives: Stratasys

New way to practice brain surgery skills before working on live patients

It’s a little disconcerting to learn that neurosurgeons don’t have many options to test drive their skills before they start practicing on patients as a Dec. 10, 2013 news release on EurekAlert about 3D printing (and a new way for neurosurgeons to practice) notes,,

Researchers from the University of Malaya in Malaysia, with collaboration from researchers from the University of Portsmouth and the University of Oxford in the United Kingdom, announce the creation of a cost-effective two-part model of the skull for use in practicing neurosurgical techniques. The model, produced using the latest generation of multimaterial 3D printers, is composed of a variety of materials that simulate the various consistencies and densities of human tissues encountered during neurosurgery. Details on the model are provided in “Utility of multimaterial 3D printers in creating models with pathological entities to enhance the training experience of neurosurgeons. Technical note.” By Vicknes Waran, F.R.C.S.(Neurosurgery), Vairavan Narayanan, F.R.C.S.(Neurosurgery), M.Surg., Ravindran Karuppiah, M.Surg., Sarah L. F. Owen, D.Phil., and Tipu Aziz, F.Med.Sci., published today [Dec. 10, 2013] online, ahead of print, in the Journal of Neurosurgery.

Here’s the disconcerting part (from the news release),

Neurosurgery is a difficult discipline to master. Trainees may spend as many as 10 years after graduation from medical school developing and honing their surgical skills before they can be designated as proficient in their specialty. The greater the number and variety of neurosurgical training sessions, the better the training experience. However, the authors point out that it is difficult to find suitable simulation models that offer accuracy and realism for neurosurgical training while keeping training costs down.

The news release provides a description of what makes the current generation of 3D printers particularly attractive for creating practice skulls, etc.,

Three-dimensional printers have been used to create models of normal and pathological human tissues and organs for physician training and patient instruction for some time. Until recently, however, only one material could be used in the creation of models. While useful for display purposes, one-material models have little value for hands-on training. With the advent of multimaterial 3D printers, the sophistication and versatility of the new models that could be created increased substantially, but so did their price.

Waran and colleagues tell us that this situation is now changing. They state that the newest generation of multimaterial 3D printers can aid neurosurgical training by creating models that simulate different diseases in a variety of body tissues, and they can do this in a cost-effective manner.

With the aid of an Objet500 Connex™ multimaterial 3D printer (Stratasys, Ltd.), researchers at the University of Malaya created a two-part model that can simulate pathological conditions in actual patients. The base piece of the model (the “head”) consists of one material. It has human features (a “face”) and the natural contours of a human skull. This piece is used to train the novice in neuronavigation techniques and can be reused again and again. The second part of the model defines the region in which simulated surgery is performed. This piece contains several different materials, which separately simulate skin, bone, dura mater, tumor, and normal brain tissue. The second piece fits into a slot in the base piece; this multi-textured piece can only be used once and is discarded after the practice session. Fortunately, it is easy to reproduce a steady stream of new pieces.

To make the training session valuable, the trainee must be able to see, feel, and even hear different “tissue” responses to surgical instruments and techniques during simulation surgery. The researchers tell us that the “skin” is designed to be pliable enough to be cut by a scalpel and repaired by sutures, yet sturdy enough to be held by a retractor; the “bone” has to be hard enough for the trainee to obtain experience using bone perforators and cutters; the “dura mater” must be thin and pliable—just like the real thing. The consistency and color of the “tumor” differ from those of the “brain” to simulate actual tissues. The researchers made the “tumor” softer than the “brain” and colored it orange, whereas they colored the brain light yellow.

To test the quality of the model produced by the printer and to make minor adjustments, the researchers from Malaysia were aided by other researchers from the UK. Three neurosurgeons and one expert in surgical simulations performed simulated surgery and assessed the model’s “tissue” components. All parts received ratings of “fair” or “good,” with most rated “good.”

The usefulness of the model in training neuronavigation techniques was also assessed. Since the two-part model was based on data from a real patient, it was no surprise that “neuroimaging” was rated “excellent” by the evaluating team. Two navigation systems were used, and in both cases “registration was accurate and planning possible.”

Waran and colleagues state that the reusable base piece of the model costs approximately US $2000 to fabricate and the disposable inset costs US $600. This makes these training models affordable. In addition, model designs are based on actual patient data, providing limitless variety.

Here’s a link to and a citation for the paper,

Waran V, Narayana V, Karuppiah R, Owen SLF, Aziz T: Utility of multimaterial 3D printers in creating models with pathological entities to enhance the training experience of neurosurgeons. Technical note. Journal of Neurosurgery, published online, ahead of print, December 10, 2013; DOI: 10.3171/2013.11.JNS131066.

This appears to be an open access paper.

Massachusetts Institute of Technology and bony 3D printing

Markus Buehler (last mentioned here in a Nov. 28, 2012 posting*, about spider silk and music) and his research team at the Massachusetts Institute of Technology (MIT) have been inspired by various biomaterials to create materials that resemble bone matter, from the June 17, 2013 news item on ScienceDaily,

Researchers working to design new materials that are durable, lightweight and environmentally sustainable are increasingly looking to natural composites, such as bone, for inspiration: Bone is strong and tough because its two constituent materials, soft collagen protein and stiff hydroxyapatite mineral, are arranged in complex hierarchical patterns that change at every scale of the composite, from the micro up to the macro.

Now researchers at MIT have developed an approach that allows them to turn their designs into reality. In just a few hours, they can move directly from a multiscale computer model of a synthetic material to the creation of physical samples.

In a paper published online June 17 in Advanced Functional Materials, associate professor Markus Buehler of the Department of Civil and Environmental Engineering and co-authors describe their approach.

The June 17, 2013 MIT news release by Denise Brehm, which originated the news item, explains the researchers’ approach in more detail (Note: A link has been removed),

The collagen in bone is too soft and stretchy to serve as a structural material, and the mineral hydroxyapatite is brittle and prone to fracturing. Yet when the two combine, they form a remarkable composite capable of providing skeletal support for the human body. The hierarchical patterns help bone withstand fracturing by dissipating energy and distributing damage over a larger area, rather than letting the material fail at a single point.

“The geometric patterns we used in the synthetic materials are based on those seen in natural materials like bone or nacre, but also include new designs that do not exist in nature,” says Buehler, who has done extensive research on the molecular structure and fracture behavior of biomaterials. His co-authors are graduate students Leon Dimas and Graham Bratzel, and Ido Eylon of the 3-D printer manufacturer Stratasys. “As engineers we are no longer limited to the natural patterns. We can design our own, which may perform even better than the ones that already exist.”

The researchers created three synthetic composite materials, each of which is one-eighth inch thick and about 5-by-7 inches in size. The first sample simulates the mechanical properties of bone and nacre (also known as mother of pearl). This synthetic has a microscopic pattern that looks like a staggered brick-and-mortar wall: A soft black polymer works as the mortar, and a stiff blue polymer forms the bricks. Another composite simulates the mineral calcite, with an inverted brick-and-mortar pattern featuring soft bricks enclosed in stiff polymer cells. The third composite has a diamond pattern resembling snakeskin. This one was tailored specifically to improve upon one aspect of bone’s ability to shift and spread damage.

The scientists are hinting that they’ve improved on nature and that may be so but I recall reading similar suggestions in studies I’ve read about 19th and 20th century research. It seems to me that scientists have claimed to be improving on nature for quite some time.

Interestingly, the suggested application for this new material is not biomedical, from the news release,

According to Buehler, the process could be scaled up to provide a cost-effective means of manufacturing materials that consist of two or more constituents, arranged in patterns of any variation imaginable and tailored for specific functions in different parts of a structure. He hopes that eventually entire buildings might be printed with optimized materials that incorporate electrical circuits, plumbing and energy harvesting. “The possibilities seem endless, as we are just beginning to push the limits of the kind of geometric features and material combinations we can print,” Buehler says.

You can find a link to and a citation for the published paper at the end of the ScienceDaily June 17, 2013 news item.

* Date changed from 2013 to 2012 on June 4, 2014

Stratasys/Objet merger and a brief bit about how 3-D printing actually works

The industry analysts seem very excited about the newly announced merger between two companies, Stratasys and Objet, that specialize in 3-D printing as Robert Cyran states in his April 16, 2012 posting on the Fast Company website,

Making physical items from digital files is a hot technology – maybe too hot if the market reaction to the acquisition of privately held Objet by Stratasys is any guide. Despite few synergies and an odd poison pill, the buyer’s shares rose nearly 25 percent, mainly on potential revenue synergies. But the future isn’t quite here yet.

Rich Brown in his April 16, 2012 posting on C/Net seems mildly more enthused,

You’ll be forgiven if you haven’t previously heard of Stratasys Inc or Objet Ltd. Stratasys, formerly a NASDAQ-traded company from Eden Prairie, MN, has a multi-pronged business selling industrial-quality 3D printers and on-demand object printing services. Objet, of Rehovot, Israel, is a 3D printer manufacturer notable for its “polyjet matrix” technology, that can print an object using multiple different materials.

Here’s why you might care that [they] announced their intention to merge: the new company, Stratasys, Ltd. could become a third major competitor in the consumer 3D printing market.

Where might newly-formed Stratasys, Ltd fit in? Neither originating firm is as large as 3D Systems, but both Stratasys Inc. and Objet Ltd. saw revenue increases over 30-percent for 2011, suggesting both companies are healthy. …”

3D Systems hasn’t really established its own name among consumer 3D printers, so it’s not clear that MakerBot really has any large competition yet. If Stratasys Ltd. does enter the consumer market, and if 3D Systems does make a credible entry, consumers will get to chose from at least three major technology originators. If that happens, here’s hoping that means more competition-induced innovation, and less court-bound patent squabbling.

I will add my wishes to Brown’s hope that this move stimulates innovation and not a series of law suits.

Oddly, I had already planned to write about 3-D printing last Friday, April 13, 2012, when I found a news item by Joel L. Shurkin on physorg.com which includes a good description of the 3-D process (Note: I have removed links),

Much of modern manufacturing is by reduction. Manufacturers take blocks of plastic, wood, or metal, and grind and machine away until they get the item they want. All the plastic, wood, or metal that doesn’t make it into the item is thrown away, maybe as much as 90 percent wasted.

3-D printing puts down layers of metal powders or plastics as directed by software, just as ink is laid down on paper directed by printer drivers. After each layer is completed, the tray holding the item is lowered a fraction of a millimeter and the next layer is added. Printing continues until the piece is complete.

Molten metal is allowed to cool and harden; plastics or metal powders are hardened by heat or ultraviolet light. The ingredients aren’t limited to those substances; almost anything that flows can be accommodated, even chocolate.

There is little waste, and it is possible to change the object by simply working with the software that drives the printer the way text is changed in a word processor.

In addition to the advantages there are also some disadvantages to the technology,

“Printing a few thousand iPhones on demand (and with instant updates or different versions for each phone) at a local facility that can manufacture many other products may be far more cost-effective than manufacturing ten million identical iPhones in China and shipping them to 180 countries around the world,” the Atlantic Council wrote in a report.

Clearly, not everyone would share the advantages. Manufacturing centers like China could lose millions of jobs in that sector, and their economies could be destabilized. The industries that transport the supply line and distribute the finished product would also be hit, the council wrote. Warehouses full of parts and products could be replaced by machines that print on demand.

Closer to home, I mentioned Stratasys and 3-D printing in a Sept. 28, 2011 posting about Manitoba’s Urbee car. My most recent mention of 3-D printing was in an April 10, 2012 posting about print-on-demand robots.

Manitoba’s Urbee

Manitoba's Urbee and its engineering team at TEDxWinnipeg Sept. 15, 2011 event

There’s a brand new car (prototype) in town. It was unveiled at TEDx Winnipeg on Sept. 15, 2011 by Manitoba-based company. From the Urbee website,

Urbee is a two-passenger hybrid car designed to be incredibly fuel efficient, easy to repair, safe to drive, and inexpensive to own.

Shortly after the TED presentation, the Urbee was featured in a Sept. 20, 2011 article by Ariel Schwartz for Fast Company and in a Sept. 21, 2011 news item for BBC News. From the Schwartz article,

Last year, Stratasys and Kor Ecologic teamed up to develop the first 3-D printed car–a vehicle that has its entire body 3-D printed layer by layer until a finished product emerges. The Urbee was just a partially completed prototype when we first wrote about it last year. …

 

The [finished] prototype, unveiled a few days ago at the TEDx Winnipeg event, is a two-passenger, single-cylinder, eight-horsepower vehicle. That means it has significantly less power than today’s vehicles, which usually have at least 68 horsepower. But those missing horses don’t matter: the Urbee requires just an eighth of the energy of conventional cars. The electric-ethanol hybrid is also designed to get up to 200 mpg on the highway and 100 mpg in city conditions–and it lasts up to 30 years.

There are more details about the printing process and its contribution to the car’s ‘greeness’ in the BBC article,

The use of “additive manufacturing”, where layers of material are built up, or “printed” to form a solid objects, contributed to the car’s green credentials, according to project leader Jim Kor.

“One only puts material where one needs it,” explained Mr Kor, who unveiled his vehicle at the TEDxWinnipeg conference.

“It is an additive process, building the part essentially one ‘molecule’ of material at a time, ultimately with no waste.

“This process can do many materials, and our goal would be to use fully-recycled materials.”

Currently it is only the Urbee’s body panels that are printed – by Minneapolis-based Stratasys. However, Mr Kor said he hoped that other parts would be produced this way in future.

Jim Kor, project leader and lead designer, very kindly answered some questions for an interview about the Urbee, which I will be posting later today.