3D-Printed Models for Training & Planning of Endoscopic Pituitary Surgery

A small gland (about the size of a small bean) located at the base of the skull, the pituitary secretes hormones and regulates the other major organs. Also known as the master gland, it is vital to good health, and can be seriously affected by over-production of hormones—or the opposite. When something goes wrong, surgery can be necessary, but tricky; for instance, endoscopic endonasal transsphenoidal pituitary surgery presents numerous challenges and risks as a procedure.

Seeking better solutions for surgeons, researchers came together to perform a recent study, detailing the results in ‘The manufacturing procedure of 3D printed models for endoscopic endonasal transsphenoidal pituitary surgery.’ Honing in on the need to provide better training—especially as cadavers can be hard to come by for both medical students and surgeons to practice on—the researchers examined the further potential of 3D printed models for improved planning.

In removing pituitary tumors, surgeons must work through the nose and sphenoid sinus, using tools to enter the nasal cavity and then actually break the bone until the sphenoid sinus is visible. This is considered to be challenging due to the complex anatomy of the nose, as well as in terms of how the sinus is situated, with the endoscope method most commonly used for surgical removal.

For this study, the authors not only propose that surgeons should be able to 3D print and customize skull models themselves but also use them ‘directly for simulation of the surgery.’ Along with that, their goal was to use a multi-tiered software system to offer better precision in creating the models from CT data.

Overview of the main goals and operations in digital model processing.

“The limited accuracy of CT scanning and threshold segmentation may cause missing features and unexpected holes in the digital model,” explained the authors, moving forward to refine the process with new software.

Set the thresholding value for Bone (CT). We select Menu bar > Segmentation > Thresholding, and set the minimum value as 226 (Bone (CT)) to get the required part of the skull model in this case. The thresholding result is saved as a new mask automatically.

Using Materialise Interactive Medical Image Control System (Mimics), they were able to improve the CT scan by fixing the holes at the base, along with using Geomagic to optimize and repair the skull base and surgical area. Segmentation consisted of extracting the nasal cavity and sellar region.

An unexpected hole on the model.

Fix the hole by drawing slice by slice. We use Menu bar > Segmentation > Edit Masks and select ‘Circle’ with reasonable size and select ‘Draw’ to connect the part.

The hole is fixed.

Comparison of the surgical area model before and after the repair.

3ds Max was used for segmentation and production of molds, correcting the surgical area and base into a polygon shape.

Slicing operations on the skull base and the nasal cavity.

The skull base with supports.

An Ultimaker 2 was used for 3D printing the base and molds, printing with PLA; however, for the surgical area, the researchers switched to binder jetting, using a 3D Systems ProJet 660 Pro with plaster.

“For the practice, the surgical area should be printed by the breakable and low-cost material (like plaster), as the sellar region will be broken during the real surgery,” explained the researchers.

Molds were used for fabrication of the soft tissue due to the expense in 3D printing the material directly. The researchers mixed pigment and silica gel to represent the following:

  • Face
  • Pituitary
  • Optic nerves
  • Internal carotid arteries

To imitate the pituitary tumor properly, the researchers set the model tumor underneath the optic nerve, using an adhesive for proper placement.

Small red dots, which look like capillaries.

The complete model and the face.

 

Surgical area models with different levels of tumors.

“With the assistance of 3D printed medical models, the surgery can be practiced repeatedly,” concluded the researchers. “The surgical safety can be improved, and the risk of death and morbidity can be reduced. In addition, the 3D printed medical model can be a good tool for the patient or their family members to learn about the disease, the condition and the risk of the surgery, which can promote the communication between the patients and neurosurgeons.”

“The outcomes demonstrate that the 3D printed skull model is able to improve the structure recognition learning. This case proves that the 3D printed anatomical model is worthy of use. Obviously, the model for specific surgery is able to improve the understanding of students or neurosurgeons on the specific or special situations.”

3D printed models are helpful today in a wide array of applications, but within the medical realm they are being used for diagnosing health conditions like tumors, as well as allowing for more streamlined treatment. Even better, such models allow more detailed explanations for patients and their families about ensuing treatments and possible surgical procedures.

Medical students are able to train with 3D printed models, surgeons can prepare for rare procedures—or those which have never been performed before—and such models may also be used as extremely helpful guides in the operating room too. Discuss this article and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘The manufacturing procedure of 3D printed models for endoscopic endonasal transsphenoidal pituitary surgery’]

 

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What Does the Future Hold for 3D & 4D Printing? Reviewing Current Processes & Ongoing Potential

Researchers come together to review both 3D and 4D printing, as well as exploring its ongoing potential in ‘Recent 3D and 4D intelligent printing technologies: a comparative review and future perspective.’

While both technologies offer great opportunity for industrial users to make and maintain functional parts and prototypes, 3D and 4D printing are a source of fascination around the world due to the ability to innovate at will, cutting out the middleman, and making new objects with new materials that may not have been possible previously.

The brief overview of relevant 3D printing methods

In the 4D realm, we see the progress being made from materials that may be less flexible to those that are able to shift with their environment—and according to the user’s needs. The authors not only delve further into fundamentals and development (especially in the evolution from 3D to 4D) but also perform comparative analysis regarding both forms of digital fabrication.

From the inception of 3D printing in the 80’s via Chuck Hull to its emergence in the mainstream and now integration into many fields—from robotics to tissue engineering, electronics, and more—the authors follow 3D printing, pointing out correctly that it is currently ‘still in the active stage of industrial innovation.’ Designers and engineers are able to take advantage of a wide variety of benefits—even including applications like fashion and jewelry.

Schematic illustration of 1D, 2D, 3D, and 4D concepts

General schematic overview of 3D printing technology with solid, liquid and power-based patterns (a) FDM; (b) SLS; (c) SLA (Sources: https://www.custompartnet.com)

While advantages such as affordability, accessibility, and greater efficiency in production are being enjoyed by many, there are still challenges regarding materials in applications like soft robotics and aerospace. With the ability to shift form while under pressure from temperature or moisture, 4D printed smart materials avail the user of greater flexibility and versatility.

“Compared  to  3D  printing,  4D  printing  updates  the  concept  of  change  in  the  printed  configuration  over  time,  which  relies  on  environmental  stimuli.  Therefore,  4D  printed  structures  should  be  fully  preprogrammed  using  time-dependent  deformations  of  products,” state the authors.

4D printing relies on:

  • Suitable hardware
  • Stimulus-responsive material
  • Stimuli
  • Interactive mechanisms
  • Mathematical modeling

SWOT analysis of a). 3D printing technology; b). 4D printing technology.

Smart materials and the ability to deform and then return to their natural shape mean that 4D printing is suitable for not only for robotics but also self-repairing of materials like hydrogels, piping, and other materials which may be related to reusability and recycling.

The illustration of shapeshifting by self-folding using water absorption materials: (a) 1D to 3D41; (b) 2D to 3D41

While one of the obstacles in 3D printing is the general need to fabricate items with only one material, 4D printing is beginning to emerge as a forerunner in applications like the medical and engineering fields.

3D printed models in the medical area (a) 3D printed heart; (b) 3D printed skull (Source: https://3dprintingindustry.com/news; sketchucation.com)

3D printing is still becoming increasingly popular, however, for use in the military field, creating weaponry and allowing for better maintenance of parts. 3D printed models are improving treatment for patients and can be used as extremely helpful pre-planning devices for surgery. Various hardware has also been created for extrusion of food like chocolate and pancake batter.

As for 4D printing, the authors expect that it will be used to create more advanced smart materials that can transform environmentally as users require, offer ‘self-controllable functions,’ expand longevity in products, and promote greater complexity in structures.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Recent 3D and 4D intelligent printing technologies: a comparative review and future perspective’]

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University of Hong Kong: Sterilization & Infection Rates in 3D Printed Models & Guides Used Intra-operatively

Hong Kong researchers explore the use of 3D printed medical models but advance in a more unique direction with concerns over infection. Detailing their findings in the recently published ‘A review of the manufacturing process and infection rate of 3D-printed models and guides sterilized by hydrogen peroxide plasma and utilized intra-operatively,’ the authors discuss the use of innovative bespoke devices for surgical planning.

As 3D printing has made impacts within the medical field, medical professionals, patients, and their families benefit due to better avenues for diagnosis, treatment, and education for everyone involved. But there are even more specific uses for 3D printed medical models today in promoting patient-specific treatment with improved pre-operative planning procedures and even intra-operative processes.

“In the specialty of orthopedics, 3D models can allow for visualization of bony anatomy and implant contouring, whilst guides can be created to direct osteotomies as well as screw entry sites,” explained the researchers.

Much attention is paid to the strides being made due to 3D printing, but outside issues such as sterility are critical to the health of patients also. Typical methods include ethylene oxide (EtO) gas and hydrogen peroxide plasma, which is a result of excitation beyond the gaseous phase—with free-radical formation allowing for sterility.

Patient eligibility and exclusion. More than 300 models were rendered by computer software from 2015 – 2019. The numbers of models proceeding to manufacturing, sterilization and intraoperative use amounted to 124. A further ten patients were excluded from analysis due to use of materials other than ABS (7 patients) as well as failure to reach 3-months of follow-up subsequent to surgery (3 patients), leaving a total of 114 patients eligible for analysis.

To date, the University of Hong Kong has produced over 300 3D models and guides. Beginning in 2015, their orthopedic academic unit began 3D printing models and guides on-site; and while they were at first fabricating models exclusively for orthopedics, over time they also began 3D printing for ‘other surgical contexts’ too. The authors confirm that out of the 300 models produced, 114 have been used for intra-operative purposes. Their review goes on to cite details regarding cases using models and guides, identifying those in which infections occurred, and highlighting risk factors.

3D printed models and guides were designed using Meshmixer and printed on a Fortus 450mc 3D printer with ABS-M30i.

Aspects of model/guide manufacturing unique to intra-operative usage. a 3D-rendering of pelvis model with initials engraved upon the left ilium to allow for correct patient identification. b Photos taken by instrument nurse demonstrating proper grouping and assembly of a surgical guide for pedicle screw placement so corresponding components may be packaged and sterilized together. The assembled guide was contoured to fit upon bony surface landmarks of the posterior spinal vertebra, as demonstrated during testing upon a 3D-model of the same patient c and during the definitive surgery (d)

3D prints were sterilized with hydrogen peroxide plasma, and low temperatures prevented deformation in material.

“A surgical time-out procedure ensured that the printout was used for the correct patient, anatomical region and procedure, in accordance to initials upon the surface,” explained the authors. “Post-operatively, printouts were similarly subject to low temperature disinfection then returned to the surgeon in charge.”

Application of 3D printouts. a Intended purpose of 3D printout showing 59/114 (51.8%) of printouts being utilized as anatomical models and 55/114 (48.2%) as guides/jigs intra-operatively. b The 124 cases utilized intraoperatively spanned different regions of the body as well as surgical specialties. The numbers relevant to each region and their percentages in relation to the whole patient cohort is shown

The researchers examined 3D prints from 124 patients with models used intra-operatively during surgical planning and management.

“Seven cases were excluded as printouts were not constructed from ABS, of which four cases utilized nylon, two case utilized polyetherimide (Ultem1010 CG), and one case utilized cobalt chrome,” explained the authors.

“Three cases were excluded because of inadequate follow-up. A total of 114 models remained for subsequent analysis. Fifty nine out of 114 (51.8%) were anatomical models utilized on-table for planning and / or implant contouring. The remaining 55/114 (48.2%) were utilized as guides or jigs specific to patient anatomy to facilitate corrective osteotomies, screw insertion or pin placement.”

Ultimately, 10.9 percent of the guides or jigs developed infections, while 3.3 percent of the models developed infections at the surgical sites.

“All six cases of guides/jigs with infection were utilized to facilitate osteotomies. Both models with infection were utilized for implant contouring, one during fixation of a pilon fracture and the other for an orbital floor blowout fracture,” stated the researchers.

Pointing out that while the infection rate of 7 percent was comparable to previous literature published regarding traditional techniques, the authors realize the importance of users to ‘be aware of potential caveats,’ despite the overall safety of the application. There are also intrinsic challenges in the fabrication of patient-specific devices and ensuring the safety of tissue biocompatibility.

Cross-section of pelvis 3D model demonstrating irregular luminal spaces. a Arrows indicate surface openings upon the posterior ilium on a 3D model of the pelvis. The dotted line and arrowhead demonstrates the level of transverse sectioning subsequently performed. Cross-sectional appearance following software rendering b and physical sectioning c of the same pelvis model demonstrating irregular trabecular spaces contained within

Intraoperative use of osteotomy guide. a Software rendered image of guide intended for corrective osteotomy and shown upon the tibial shaft (b) with the osteotomy site marked in teal. c Intra-operative photo with the guide secured and oscillating saw engaged in preparation for osteotomy and (d) upon completion. e Intra-operative x-ray demonstrating reduction and fixation of the tibial shaft following corrective osteotomy. f Similar guide retrieved post-op demonstrating damage to ABS over the osteotomy slit with the potential to release debris

“It is worth noting that prior studies detailing infection-related outcomes of 3D printouts have not explicitly utilized them intra-operatively, and this is one of the first studies to have done as such. Our overall impression was that our process of sterilization and on-table usage is safe, and that surgical complexity and tissue manipulation as reflected by increased operating time were the main culprits for infection,” concluded the authors.

“In detailing the design, printing, and sterilization of 3D printouts as well as infection-related outcomes amongst this sizable cohort, we demonstrate that our production process is safe for continuation and may be adopted elsewhere.”

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[‘A review of the manufacturing process and infection rate of 3D-printed models and guides sterilized by hydrogen peroxide plasma and utilized intra-operatively’]

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China: Smart Phones as Imaging Devices for Human Bones to be 3D Printed & Used in Education

Researchers from China assess the further potential for the smartphone in medical applications, outlining their findings in ‘Evaluating phone camera and cloud service-based 3D imaging and printing of human bones for anatomical education.’

Historically, training on real bodies is one of the best ways for medical students to learn—but cadavers are often not available globally. To make up for that, as technology has progressed, so have a wide range of simulation programs and visual aids. Today, 3D printed medical models and an array of devices are able to offer comprehensive benefits for diagnosing, treating, educating patients, planning for surgeries, and more. Medical students (as well as experienced surgeons) can also benefit enormously from models which may feature tumors about to be operated on in new or rarely performed procedures.

“The primary advantage of 3D printing lies in its ability to create graspable shapes or geometric features of high complexity, overcoming the limitations brought about using flat screens for the visualization of 3D imaging data. Moreover, compared with embalmed cadaveric specimens, 3D printed models are more wear-resistant, easier to clean and store, and, essentially, environmentally green,” state the researchers.

While many industries are benefiting from 3D printing, the impacts are undeniably vast within the medical arena, as anatomical models allow for training and planning, and offer an ‘increasingly significant role’ in developing countries like India.

“In effect, reports indicate that 3D printing helps to improve the effectiveness of teaching and that students learning with 3D printed models performed even better in tests than those learning with real specimens,” stated the researchers.

There are still challenges and limitations in terms of 3D printing as the technology continues to evolve within the medical field; however, education and knowledge of special equipment has been a specific concern. The researchers were motivated in this study to offer technology that is easy to use via phone-based 3D imaging, requiring a basic 3D printer to fabricate models.

Flow chart of technical route. Three main stages are involved. first, specimens acquired are photographed from all around to obtain enough 2D images from all possible directions. Second, 2D images are converted into digital models with a cloud-based specialized server. Third, after editing, digital models and 3D printing setting data are applied to 3D printer for printing. 2D, two dimensional; 3D, three dimensional.

The following sample bones were used for imaging: femur, rib, cervical vertebra, and skull. Specimens were photographed repeatedly while spinning on a turntable.

“During our testing, the photographer held the phone and captured the images with one hand and rotated the turntable with the other hand after each shot. Two rounds of photography were carried out on different horizontal planes,” explained the researchers.

Original specimens, digital models and 3D printed models made with SLA technology. (A) femur, (B) rib, (C) cervical vertebra, (D) skull (the digital models may seem smaller because of the special display mode in materialise magics, which is different from single perspective). 3D, threedimensional; SLA, stereolithography apparatus.

Each specimen was photographed 80-100 times, with the photos being uploaded to Get3D and the converted files sent to an online 3D printing service in China. The researchers stated that the costs of the 3D printed femur, rib, cervical vertebra, and skull were USD $20.27, $3.96, $1.13, and $35.40, respectively.

Analysis of deviation between original specimens and 3D printed models. Gradation on the deviation spectrum is 0.5mm each; green colour indicates deviations ranging from −0.5 to 0.5mm; hot colour indicates positive deviations ranging from 0.5 to 2mm; cool colour indicates negative deviations ranging from −0.5 to 2mm. deviation analysis of (A) femur, (B) rib, (C) cervical vertebra; (D) distribution of deviations (in %). 3D, three-dimensional.

Analysis of the deviation between digital models and 3D printed models. Gradation on the deviation spectrum is 0.5mm each; green color indicates deviations ranging from −0.5 to 0.5mm; hot color indicates positive deviations ranging from 0.5 to 2mm; cool color indicates negative deviations ranging from −0.5 to 2mm. deviation analysis of (A) femur, (B) rib, (C) cervical vertebra; (D) skull; (E) distribution of deviations (in %). 3D, three-dimensional.

Upon evaluation, the researchers confirmed that their method offered a ‘fairly high precision’ in digital and 3D printed models.

“The most noteworthy feature of the proposed workflow is that it works without scanners or the CT/MRI dataset, thus enabling a broader range of 3D printing technology for educational applications,” stated the authors.

The models offered a good display of anatomical features; for example, the nutrient foramina on the femur was ‘observed easily.’ This was noted in comparison to previous research where an FDM 3D printer using ABS rendered a similar femur sample to be invisible in the area of the nutrient foramina. For this study, SLA was chosen, with Somos Imagine 8000—a rigid material that is tough, dense, and easy to clean.

“The 3D printed models created using the photogrammetry method demonstrate only the external features of the bone specimens; the inner structures are invisible. Human specimens also have this limitation. To display the different anatomical landmarks on the interior of the skull, three or four differently dissected specimens must be used. The same strategy can be applied while creating 3D printed models that display different anatomical structures—differently dissected or sliced specimens are chosen as the resources to be put through photogrammetry,” explained the researchers in their final discussion.

“The photogrammetric digitization workflow adapted in the present study demonstrates fairly high precision with relatively low cost and fewer equipment requirements. This workflow is expected to be used in morphological/anatomical science education, particularly in institutions and schools with limited funds or in certain field research projects involving the fast acquisition of 3D digital data on human/animal bone specimens or on other remains.”

Comparison of fine structures among specimens, digital models and prints. (A) Nutrient foramina in the great trochanter (above) and the fovea for ligament of head (below). (B) Nerve foramina in cranial base (above) and intraorbital structures (below). (C) Tubercle of the rib. (D) Nutrient foramina in vertebral body

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[Source / Images: ‘Evaluating phone camera and cloud service-based 3D imaging and printing of human bones for anatomical education’]

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Patient-Specific Anatomical Models for 3D Printing and AR/VR

Researchers from the US and Canada have released a supplement to their Radiological Society of North America (RSNA) 2018 hands-on 3D printing course, reviewing techniques for creating 3D printed cranio-maxillofacial (CMF), orthopedic, and renal cancer models. These models can also be viewed in both virtual and augmented realities, as outlined in their recently published ‘Creating patient-specific anatomical models for 3D printing and AR/VR: a supplement for the 2018 Radiological Society of North America (RSNA) hands-on course.’

As 3D printing becomes more accessible, affordable, and less intimidating to users in the mainstream, hospitals and doctor’s offices are beginning to use this technology on-site and on-demand in offering more patient-specific care—whether in the creation of models or medical devices. Both augmented reality (AR) and virtual reality (VR) tend to accompany 3D design and printing also, especially in the medical field where visualization is key in making diagnoses, planning treatment, and educating patients, their families, and medical students too.

“In order to efficiently create 3D printed anatomic models and to use them safely for medical purposes, radiologists and medical professionals must understand the process of converting medical imaging data to digital files,” state the authors.

“Therefore, to educate radiologists and other medical professionals about the steps required to prepare DICOM data for 3D printing, hands-on courses have been taught at the Radiological Society of North America (RSNA) annual meeting since 2014.”

Their courses are for educational purposes only, and not the promotion of any products, emphasizing the use of ‘FDA-cleared software,’ with examples in this case representing craniomaxillofacial (CMF), orthopedic, and renal cases.

In creating optimized models, suitable parameters must be considered, along with the following:

  • Spatial resolution (approximately 1 mm3)
  • Reconstruction kernel
  • Multi-phase contrast
  • Metal artifact reduction
  • Sequence parameters for MRIs

As a note, it is generally not cost-effective to perform repeat imaging—along with presenting concerns regarding excess exposure to radiation.

Stages of the anatomical modeling process

Image processing was provided by Mimics inPrint, allowing the researchers to fabricate anatomic regions of interest from the DICOM data. Workflow was comprised of the following steps:

  • Create ROI
  • Edit ROI
  • Add part
  • Edit part
  • Prepare print

The main tools used include:

  • Zoom
  • Pan
  • Scroll
  • Zoom
  • Navigate with one-click
  • Threshold adjustment

Mimics InPrint workflow steps including 1) Create ROI, 2) Edit ROI, 3) Add Part, 4) Edit Part, and 5) Prepare Print

Three cases were followed:

Pelvic fracture – with the 3D printed model, the researchers were able to help surgeons visualize features of the bones fragments and strategize regarding any impending surgery.

“3D printed pelvic models can also lead to improved perioperative outcomes as compared to patients treated with conventional pre-operative preparation,” stated the researchers. “Mirror images of the opposite intact hemi-pelvis may also be created and can be used to pre-contour fixation plates and these have been reported to reduce surgical times.”

a Coronal CT image showing threhsolded right pelvic bones, showing similar colors for the pubis, ischium, and femur. b Coronal CT image showing splitting of the pelvis (blue) from the femur (black). c 3D computer model showing the pubis (white) and ischium (yellow). d Photograph of 3D printed model

Mandible tumor – 3D printed models help everyone involved understand the anatomy of the mandible, from the patient to the doctor to the medical student and may also serve as surgical pre-planning guides.

“To best depict this anatomy, we chose to print using material jetting (Stratasys J750, Eden Prairie, MN) with the mandible transparent and the tumor and nerves in high presence colors such as blue and green,” stated the researchers. ‘The total print time for this model was 9 h and 24 min using a high mix print setting.”

a Axial CT image showing segmentation of teeth (green) and tumor (yellow). b 3D anatomical regions of interest including the tumor (blue), mandible (white), teeth (white), and nerves (green). c 3D visualization of model including all anatomical parts. d 3D printed mandible tumor model including the mandible (clear), teeth (white), tumor (blue), and nerves (green)

Kidney tumor – 3D printed models can be used for both the nephrectomy process as well as planning ablative therapy. The model can be used for evaluating the status of the tumor, as well as its proximity to other anatomy. The model can be used for training purposes as well as helping reduce time in the operating room.

a Coronal CT image showing aorta and right renal artery selection. b 3D visualization of segmented arterial structures. c Remaining arterial region after trimming has been performed

“AR or VR models can be created for all the cases list too, exported and then prepared in Unity,” concluded the researchers.

3D kidney tumor model visualized a in AR using the HoloLens AR headset (Microsoft, Redmond, WA), b in VR using Syglass software (Syglass, IstoVisio, Inc., Morgantown, WV) in combination with the Oculus Rift (Facebook, Menlo Park, CA), and c in VR using the Sketchfab app (Sketchfab, New York, NY) and a smartphone device. Each structure is numbered so that the unfamiliar user can easily identify each individual structure: 1 – kidney, 2 –vein, 3 – artery, 4 – collecting system, 5 – renal tumor

3D printed medical models have added not only a huge educational quotient in terms of teaching patients, medical students, and more, but also allow surgeons to pinpoint tumors, plan for hip surgeries, healing fractures, educating aneurysm patients, and more.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Creating patient-specific anatomical models for 3D printing and AR/VR: a supplement for the 2018 Radiological Society of North America (RSNA) hands-on course’]

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3D Printing for the Segmental Scapula Prosthesis  

In the recently published ‘Application of a three-dimensional printed segmental scapula prosthesis in the treatment of scapula tumors,’ authors Linglong Deng, Xing Zhao, Chi Wei, Wengiang Qu, Li Yu, and Shaobo Zhu explore better ways to salvage limbs, focusing on the potential found in 3D printing.

While there are a host of benefits that make 3D printing enticing to the medical community overall—from the affordability factor to speed in production—what is most groundbreaking is the ability to offer patient-specific treatment. For this study, the authors focused on the effects of chondrosarcoma has on the scapula (a part of the body most commonly known as the shoulder blade).

Imaging examination findings of the left shoulder. (a) An X-ray showed an irregular shadow with a bone lesion on the scapula, situated in the S1 region. (b) A computed tomography scan revealed a moderate low-density bony lesion.

Due to aggressive tumors caused by chondrosarcoma, along with the resulting irregular patterns, limb salvage is usually recommended. Offering implants is known to be a challenge, and while limb salvage is often the best course of action, that does not mean it is simple. Today, chondrosarcomas are responsible for 20 percent of malignant bone tumors, stealing functionality from the shoulder for many patients, as well as shortening their lives in all too many cases.

“After resection of the tumor, we were eager to obtain a prosthesis with the same size and shape as the original removed portion without the tumor,” stated the researchers. “Hence, we viewed a mirror model of the scapula from the healthy side as an affected side implant. Consequently, having used mirror imaging technology, we synthesized the 3D image file of the S1 region of the left scapula without tumor and named it N-S1 (that is the prosthesis) according to the right scapula. Finally, the STL files were uploaded to a Tornier 3D printer (SAS, Montbonnot, France) to acquire a solid 3D model consisting of nylon resin material.”

Ultimately, the prosthesis was created from titanium and screwed into the scapula. After four weeks, the patient was able to move his hand, elbow, and shoulder, and is still in good condition with no pain in the shoulder. The researchers point out that 3D printing allows for ‘accurate reconstruction,’ but there is much to be considered before performing a successful procedure like this as the prosthesis must always be customized for the patient due the irregularity of tumors, leaving it properly shaped and stable for connection to what is left of the scapula after the mass is removed.

Major intraoperative surgical procedures. (a) The osteotomy navigation template was attached to the scapula landmark to assist with tumor resection. (b) The excised tumor tissue. (c) The remaining rotator cuff was reconstructed with the prosthesis.

With 3D printing, the researchers were able to simulate the procedure, training ahead of time, as well as contouring the reconstructive plate. The operation was successful, streamlined due to the previous simulation, and with a ‘perfect match’ shown between the prosthesis and scapula. They did note some constrictions, however:

  • The entire process—from 3D design to completion of surgery—was time-consuming.
  • The technology and materials were expensive.
  • Follow-up time was ‘relatively short.’

Overall though, with 3D printing they were successful in reconstruction, customization, and even more with the allowed simplification of operations which are generally otherwise complicated.

“The 3D printing technology can fulfill the requirements of a highly individualized design, thereby displaying unique advantages in the manufacturing of the implant,” concluded the researchers.

The impacts that 3D printing is having on the medical realm are enormous, and 3D printed models as well as implants have changed the lives of patients all over the world, educating surgeons and medical students about tumors and necessary surgeries, and offering new methods of treatment. What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

Solid three-dimensional model of the left scapula and preoperative simulation. (a) A navigation template stuck to the removed portion of the scapula (S1). (b,d) The nylon and titanium alloy prostheses (N-S1) were printed using mirror imaging technique. Many holes were designed at the edge of the prosthesis for soft tissue reconstruction. (c) The retained portion of the scapula (S2) and the prosthesis (N-S1) matched well via the reconstruction plate shaped in advance.

[Source / Images: ‘Application of a three-dimensional printed segmental scapula prosthesis in the treatment of scapula tumors’]

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Chinese University of Hong Kong Studies 3D Printing for Heart Disease

In the recently published ‘Three-dimensional printing in structural heart disease and intervention,’ authors Yiting Fan, Randolph H.L. Wong, and Alex Pui-Wai Lee, all from The Chinese University of Hong Kong, explore the potential for 3D printing in the world of medicine, as well as cardiology—and more specifically, structural heart disease (SHD).

SHD causes issues like:

  • Aortic stenosis
  • Mitral regurgitation
  • Atrial septal defect
  • Left atrial appendage (LAA) clots

Conventional imaging is limited, while the emergence of 3D printed models allows medical professionals to progress from mentally reconstructing 2D images to gaining a more complex understanding of pathology.

As 3D printing continues to make its way into the realm of medicine, models are used for:

  • Guiding treatment
  • Procedural simulation
  • Facilitating hemodynamic research
  • Improving interventional training
  • Promoting patient-clinician communication

To create a medical model, images must be attained, data must be processed, and the object must be 3D printed.

“The most commonly used imaging sources for SHD are echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI),” state the researchers. “Other modalities, such as positron emission tomography, single photon emission CT and cone beam CT, are less commonly used. All images should use the common Digital Imaging and Communication in Medicine (DICOM) format.

Pre-procedural simulation of MitraClip on 3D-printed model. (A) Digital model of a heart. Different colors stand for different cardiac components (grey: mitral valves; light pink: tricuspid valves; light gold: atrial septum, left atrium, left and right ventricle). (B) Multi-material 3D-printed heart model for pre-procedural simulation. The valves were printed with flexible material and the rests were printed with hard material. (C) The 5 holes drilled in the atrial septum represents the different position for different kinds of structural heart interventions. (D) The MiraClip device was released via delivery catheter through the atrial septum to the mitral valve. Blue circle: MitraClip; red circle: left atrial appendage occlusion (LAAO). S, superior; A, anterior; P, posterior; I, inferior; IVC, inferior vena cava; LAA, left atrial appendage; MV, mitral valve.

A range of materials are both popular and possible for fabricating medical models:

“Multi-material printing by material jetting is increasingly used to create cardiac structures. Different tissue components were printed with different textures. For instance, an aortic valve was printed with flexible printing material, and the calcifications attached to valves were printed with hard printing material, respectively,” report the authors.

Application of 3D printing for peri-device leak. (A,B,C) A case found with peri-device leak post TAVI and needed peri-device leak occlusion: (A) routine TEE post-TAVI showed peri-device leak (yellow circle); (B) simulation of peri-device leak occlusion on 3D-printed aortic root model derived from post-TAVI CT; (C) the 10-mm vascular plug was found to be best-fit for this case. (D,E,F,G) A case found with residual leak after ASD closure: (D) multi-material 3D printed model showed residual leak (blue circle) next to the ASD occluder (asterisk *); (E) the delivery catheter went through the leak position; (F) the device (two asterisks **) was released in situ. (G) The bicaval view of 3D-printed model showed stable release and stay of the chosen device. 3D, three-dimensional; TAVI, transcatheter aortic valve implantation; TEE, transesophageal echo; CT, computed tomography; ASD, atrial septal defect.

There continue to be ongoing challenges in the creation of medical models, however, ‘despite the enthusiasm in applying 3D printing cardiovascular medicine.’ While there is an obvious lack of technical standards, mainly due to the novelty of the technology, the authors point out also that there are still issues with affordability—along with ‘scant evidence on the added clinical benefit.’

Greater accuracy is needed, along with improved standardization of data acquisition, and post-processing techniques. While deeper research is required into the creation and use of models and surgical guides, so are comparisons for offering up better information and creating industry standards. The authors also recommended a more streamlined workflow.

“The mechanical properties of the 3D-printed materials, such as tensile strength, elasticity, flexibility, hardness, and durability have utmost importance for cardiovascular applications. The majority of cardiovascular applications reported so far have employed materials with properties that have not been meticulously compared with the cardiovascular tissue they are mimicking. Validation of 3D-printed material properties against actual human patient tissues is important to ensure that procedural simulation is realistic,” conclude the authors.

“Further effort in technical standardization, and clinical evaluation of added benefit and cost-effectiveness of 3D printing are needed to bring this promising technique to clinical reality.”

3D printed medical models are extremely beneficial to doctors and patients as they allow not only for diagnosing but have also continued to change medicine—allowing for procedures involving complex reconstructions, fabrication of surgical guides, and much more.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Three-dimensional printing in structural heart disease and intervention’]

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Florida: Advent Health Nicholson Center Opens 3D Printing Protoype Lab

Advent Health Nicholson Center of Celebration, FL, has just announced the launch of their Prototype Lab, an innovative new medical facility meant to encourage medical professionals in taking their ideas from a mere concept to reality—creating models and even devices that have the ability not just to change lives, but sometimes save them too. This is the wave of the future, with personalized medicine.

(Image: Advent Health Nicholson Center Prototype Lab)

Advent is known as one of the world’s leading medical training centers, continuing to provide new technology, industry knowledge, and testing. The Prototype lab will be open to physicians, researchers, engineers, and other medical professionals engaged in creating prototypes for devices.

They will have access to CAD modeling software, 3D printing, and different avenues for testing and changing designs easily.

“Our expert team can help bring an idea from ‘napkin sketch’ to reality, and our 3D printing capabilities allow inventors to hold an actual version of their device in their hands for evaluation,” said Jodi Fails, B.S., Biomedical Engineer and Prototype Lab lead at AdventHealth Nicholson Center. “Most product developers assist with creation but have to look externally for lab testing. However, with Nicholson Center’s Prototype Lab, we have the unique ability to take inventions straight from the printer to the lab for immediate testing on high-quality tissue.”

In the Prototype Lab, inventors submit their concepts to engineers who take time to understand the concept being presented, create an initial design, also very importantly—they submit a patent search to make sure there will not be any intellectual property conflicts. Once CAD 3D modeling has been completed, the design is brought to life on an in-house Objet350 Connex3 polyjet printer.

For prototyping, the Object350 is capable of printing over 1,000 different materials, to include:

  • Rigid plastic
  • Flexible rubber
  • Transparent materials
  • Full-color materials

New devices can be tested at on-site labs and can even be reviewed by the FDA.

“Beyond the technology and testing capabilities at Nicholson Center, our experts bring the pivotal industry knowledge that is so crucial to the early stages of product development,” said Lilly Graziani, Director of Corporate Development at AdventHealth Nicholson Center. “With a key balance of tradition and innovation, our engineers, physicians and clinical staff work with inventors to create a product that will reach the medical community’s ultimate goal: improving patient outcomes.”

3D printing in medicine opens the potential for impacts on a massive scale and with a multitude of labs and medical facilities already embracing the benefits of 3D design and on-demand printing. And while the technology emerged due to the curiosity and design needs of brilliant engineers in the 1980s today it is still used for its most central use: rapid prototyping.

While there are numerous medical inventors today who have created functional components and devices, the use of the prototype or model is still intensely valuable as it offers so much to everyone involved within the treatment process. First, with a 3D model being made from CT scans or X-rays, doctors and surgeons can not only diagnose an issue but can decide on a course of treatment. And while medical devices may solve a host of health problems or offer treatment, 3D printed models can be used to educate patients and their families, teach medical students and act as surgical guides in the operating room.

To learn more about the Prototype Lab or to schedule a consultation, click here.

(Image: Advent Health Nicholson Center Prototype Lab)

3D printed models are being used around the world today to explore health issues like tibial fractures, heart valve complications, and more, along with paving the way to better access in learning and sharing as medical professionals even have access to online libraries for files that can be downloaded for cases such as cardiac care.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

(Image: Advent Health Nicholson Center Prototype Lab)

[Source / Image: Advent Health Nicholson Center press release]

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Mayo Clinic is Using 3D Printing to Teach the Next Generation of Spine Surgeons

Resident life is hard. After years of living, studying, and breathing medicine, they are finally one step closer to officially being able to practice. Medical residencies can take three years for primary care physicians, but some surgical specialties require even more training time to develop new procedures without risking lives, sometimes up to seven years. And did we mention that training is not a breeze? Its hard work and some of it is not for the queasy.

Residents need cadavers for educational purposes, but these are difficult to come by. In the United States, only 20,000 bodies are donated to science every year, that’s barely enough to satisfy a population of more than 27,000 residents. Plus you need to add the costs of purchasing them, according to an article by The New York Times, delivery of an intact cadaver costs as little as $1,000, but different specialists seek out specific pieces of anatomy for their work, and individual parts can be expensive, such as a torso in good conditions which can go for $5,000, or a spine for $3,500. With residents needing more than one cadaver to practice on and clinics usually having only limited resources, there is a sensical need to find new ways to educate the next generation of doctors. For William Clifton, Neurosurgery Resident at the Mayo Clinic in Florida, it seemed there had to be another way to train surgeons, so he consulted with an engineer, who was also a friend, and realized that creating 3D printed models for medicine and simulators for resident training could be the solve-all solution.

Clifton had an idea which involved buying an Ultimaker S5 FDM desktop printer with a personal loan, and finding room at home to begin printing out models in his free time, not an entirely easy job considering the young doctor and his wife have four children. But Clifton, one of the first recipients of the Mayo Clinic John H. and Carolyn O. Sonnentag Neurosurgery Residency in Florida, was on a mission, one he became very passionate about, using 3D printing technology to build simulators that can be used to train residents for surgery. Along his path, he ran into Aaron Damon, a researcher and lab specialist at the Simulation Center at Mayo Clinic, and immediately discovered that they shared a desire to change the future of resident training.

His early designs helped him build the training models used today. Since last March, they have developed hundreds of their original Biomimetic Human Tissue Simulators, more than 30 peer-reviewed publications, as well as several patent submissions for neurosurgical devices. The Department of Neurologic Surgery also became heavily engaged in planning for dedicated neurosurgery 3D printing space and there is now a materials science laboratory based on the ideas and infrastructure Clifton helped create. Today their lab houses three FDM printers: two Ultimaker S5 and one Raise3D Pro for bigger volumes, such as when they need to print cases of scoliosis (a medical condition in which a person’s spine has a sideways curve) to help residents that need to deal with pediatric scoliosis. 

“We are using 3D printed patient-specific models in a certain way to characterize the material properties of actual bone, soft tissue, muscle, ligaments, tendons, and more, exactly how it is in vivo,” said Clifton in an interview with 3DPrint.com. “The big innovation is that our models exhibit the same biomechanics as the human spine or the human skull so that the surgeon can see where the structures are in realtion to each other, bend and move them, as well as watch how the dynamic relations change.” 

According to Mayo Clinic, the 3D printing process comprises stripping down information from a patient’s CT scan and converting the image to stereolithography. Based on spatial information, Mayo Clinic can program the printer to create patient-specific models, such as anatomically precise vertebrae. Physician-scientists use these surgical training models in tandem with resources provided by the J. Wayne and Delores Barr Weaver Simulation Center at Mayo Clinic’s campus in Florida. The Weaver Simulation Center partnered with Clifton to share his 3D training models with surgical learners.

The real innovation was simulating human tissue and creating a new polymer for FDM 3D printing of anatomical models that will be used for practicing pre-surgical operations using electrocautery, something that has never been done before. The innovative new polymer chemistry and the 3D printed film should be commercially available soon as Clifton and Damon are in talks with multiple companies through Mayo Clinic Ventures (the business office at Mayo that handles this type of negotiations and commercialization).

3D printed phantom for teaching neurosurgical trainees the freehand technique of C2 laminar screw placement

“The faculty is ecstatic about this project because the skill of the residents has gone up considerably. Traditionally interns learn on cadavers or during the residency in living people. For example, surgical residents have to learn to place screws into the C2 vertabrae and this is a complex procedure because they are learning to navigate between the vertebral artery and the spinal cord; but with our models they can practice puting in a couple of hundred C2 pedicle screws so that when they go to the Operating Room (OR) they know exactly what to do, because they have done it so many times on such reallistic models,” claimed Clifton, whose specialty as a neurosurgeon leads him to perform surgery on the brain, spinal cord, and peripheral nerves.

Mayo Clinic is all about research, education and patient care, which is why Damon and Clifton are printing their way into teaching future doctors how to take care of the next generation of patients. The duo gets along extremely well, understanding that cooperation and collaboration are one of the keys of their success, which will shortly be used in the other two Mayo Clinics, in Rochester and Arizona. In the short eight months since their adventure began, they have created 14 different models for spine pathologies alone, and now they will begin developing brain models. Damon indicated that they have a brain tumor resection model in the works, “that residents can use to practice the removal of a brain tumor, coagulation of vessels, measuring blood loss, brain manipulation, and even brain mapping, meaning that now we are going into the microsurgery skill set, and not just spinal surgeries.” 

“We can print a lot of different pathologies, wereas you are kind of limited with a cadaver. With 3D prinitng you can model specific pathologies after a patient, as well as complex and rare pathologies that residents might not see that often in the OR,” explained Damon. “This is a very specific and universal development at the same time, because we hope that other clinics around the world that barely have any access to cadavers for resident training, can use them and eventually this will improve outcomes and lives all over the world.” 

Each simulator costs approximately $50, whereas a cadaver normally purchased for this type of surgery training can run into the thousands, helping Mayo Clinic save thousands of dollars as well. The medical center, which ranks as the best clinic for neurosurgery worldwide, will still get cadavers of course; but Clifton recalled that he spent over $50,000 in just three months, on cadaveric tissue for research and education in 2018. That experience and the reality of the burden of costs behind his training is one of the reasons that sparked the interest in developing a more cost-effective way to practice.

“One of the distinct advantages of FDM 3D printing specifically is that it allows us to build models made from different material compositions and properties. We do this to simulate different disease processes for resident training, and to approach patient care and surgical planning in an individualized way,” said Clifton.

Clifton and Damon want to take this technology to the point where it is streamlined so that residents will have dedicated simulation training. The key is that even before they hit the OR, they have done the procedure at least 10 times, and not just the simplest parts of the procedure, but also all the complex elements. Their hope for the future is that this will become a standardized model in the US.

Damon suggested that a big part of their work has been refining and validating their models until they achieved a high fidelity that is comparable to cadavers. “With these simulators, residents are able to acquire the same skill level as surgeons who have been in the field for many years by high fidelity and cost-effective repeated practice. The support we get from Mayo Clinic also allows our creativity to grow and continue to push the boundaries of innovation in 3D printing.”

Damon suggested that “even in our lab at Mayo, there were up to five surgical residents sharing one cadaveric torso, but now each person can have their own model and countless amount of experience, which is invaluable.” The two experts claim that training on cadavers gives residents one chance of getting a procedure right, while models can be 3D printed hundreds of times. 

Three of Clifton’s patients recently benefited from his applications in 3D printing. The unique models contributed to surgical planning sessions, helped to pinpoint precise diagnoses and guided postoperative management choices. The first patient had a congenital spinal deformity, the next had a large metastatic tumor near the lumbar spine, and the third had a rare cyst compressing her brainstem. All three patients have recovered from their successful surgeries because of the combined forces of innovation and surgical skills.

“We are really looking into the education component, trying to obtain a better, safer and cheaper solution for the future. My goal is to teach the next generation of residents to become great spine surgeons.”

[Image credit: Mayo Clinic]

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Surgeons Turning to 3D Printing & Pre-Surgical Planning for Jaw Surgeries in Korea

In ‘Comparison of time and cost between conventional surgical planning and virtual surgical planning in orthognathic surgery in Korea,’ authors Si-Yeon Park, Dae-Seok Hwang, Jae-Min Song, and Uk-Kuy Kim explore the topics of 3D printing in the medical realm, but in regards to a very specific type of procedure. The study involved patients undergoing surgery of the jaw at the Pusan National University Dental Hospital from December 2017 to August 2018.

Intense planning is required for orthognathic surgery, with ‘accurate and delicate’ patient data analysis required. Traditional analysis is detailed and arduous, while virtual surgical planning (VSP) and 3D analysis involve:

  • Analyzing skeletal deformities
  • Performing virtual surgery
  • Fabricating a surgical stent

Patients involved in the study had received Le Fort I osteotomy and bilateral sagittal split osteotomy (LFI+BSSO) or only bilateral sagittal split osteotomy (BSSO). Preoperative steps were taken at the hospital, with surgical planning performed through conventional and virtual methods. Patients were divided into two groups:

  • Group One – patients who underwent LFI and BSSO regardless of genioplasty
  • Group Two – patients who had undergone BSSO regardless of genioplasty

All patients underwent radiography. For Group One, the patients required maxillary and mandibular impression, with facebow transfer required for conventional analysis. For Group Two, the patients needed one pair of maxillary and mandibular impressions. The study included 47 patients, all of whom underwent surgery performed by one surgeon.

While conventional planning may often be responsible for errors, along with diminishing accuracy, virtual planning offers all the opposite benefits, preventing mistakes and improving precision and accuracy. Many surgeons are turning to VSP because of the many advantages outweighing more traditional techniques.

Stent fabrication progress in conventional surgical planning

Along with being more accurate, VSP is also much faster; however, affordability—while theorized to offer a great advantage—did not factor in during this study. Virtual planning was found to be more expensive because the stent was outsourced for fabrication. The surgeon involved in the study still expects that VSP would be more cost-effective when all factors are considered—and especially in the amount of time saved.

Virtual surgery in virtual surgical planning

Stent fabrication progress in virtual surgical planning

“In this study, each step of VSP and CSP was not performed in the same place. Since it was performed separately, it is possible that its accuracy and cost-effectiveness decreased when it was processed in different laboratories,” concluded the researchers. “As a result, if the hospital is well equipped with software and hardware, each step of VSP and CSP can be performed in the same hospital and it will increase the cost-effectiveness and accuracy of the process by reducing errors and extra charges from the outsourced laboratory.”

“With its high accuracy and time efficiency, VSP is the future for orthognathic surgery planning. As the VSP program continues to evolve, research on how to reduce the work time and cost for each step should be done.”

3D printing has made enormous impacts in the vast field of medicine, but especially the world of 3D models and surgical pre-planning. This spans so many different types of procedures meant to study, diagnose, and treat issues such as prostate cancer, knee replacement, and even prevention of heart-valve complications.

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Progress workflow and performer for CSP and VSP

Average time for each step in CSP and VSP

[Source / Image: ‘Comparison of time and cost between conventional surgical planning and virtual surgical planning in orthognathic surgery in Korea’]

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