Critical Analysis on the Anatomics Acrylic Custom Cranial Implant

The Anatomics Acrylic Custom Cranial Implant 2016 is a patient specific 3D printed medical device. The custom made piece is a part of the Anatomics Pty Ltd surgical products, designed to aid implant technology and save time in operating theaters. The need for cranial reconstruction, as seen in the Anatomics Acrylic Custom Cranial Implant 2016 is to rebuild contours of the skull and normalise their functions. Throughout this critical analysis, I will discuss the central ideas within the piece, as well as Anatomics intent. I will also explain the main materials in the custom implant, polymethyl methacrylate in detail, along with other physical attributes, and how they contribute to the design. This will be followed by an explanation of the processes required to develop the custom implant, as well as speculation of these choices. The remaining content will explore experimentation with new and existing technologies, alongside a final critical examination of the Anatomics Acrylic Custom Cranial Implant 2016.

Central ideas present:
The central ideas explored in the work stem from Anatomics pioneered technology in CT scannable surgical implants. Anatomics cutting-edge technology is designed to produce enhanced surgical outcomes and save valuable operating theater time (Anatomics Pty Ltd 2017), as seen through their vast choice of material and design process. Their innovative nature has launched this technology into a niche market that sanctions surgeon and patient collaborative work. Working hand in hand with healthcare professionals, resin technology companies, and specialised medics has made surgical procedures smoother and more comfortable for patients. Clearly, this is a central idea explored in the Anatomics Acrylic Custom Cranial Implant 2016. This leads me to my next point, the intentions of the work.

Anatomics intention:
As stated, the Anatomics Acrylic Custom Cranial Implant 2016, and other Anatomics technology are designed with the intention to ease surgery and provide more comfort for patients. In the case of the Anatomics Acrylic Custom Cranial Implant 2016 in particular, it has been designed with the intention of a patient who had part of their cranium removed during surgery, following traumatic brain injury (Anatomics Pty Ltd 2016). Its key purpose is to restore skull structure after serious bone trauma. Anatomics objective is to make the implant process, from its design, production and material choice as safe and smooth as possible. I will discuss these points in details further along by explanation of materials, the design process, and operative process.

Physicality of the work:
The Cranial Implant is created from polymethyl methacrylate (PMMA), a shatterproof plastic which is often used replacement for glass (Polymer Science Learning Centre 2017). PMMA is a profound material that is obtained from propylene, a compound “refined from the lighter fractions of crude oil” (The Editors of Encyclopædia Britannica 2009). A further vast combination of elements, such as benzene, which oxidized to cumene hydroperoxide, followed by other processes develops methyl methacrylate. This product is then transformed and polymerized. Polymerizing consists of molecule linking together in large volumes, forming incredibly strong bonds. It is this polymerization that creates polymethyl methacrylate (The Editors of Encyclopædia Britannica 2009)

The processes PMMA undergoes to generate its strength is crucial in the overall implants strength, purpose and durability. The strength of the synthetic resin is required for lifetime fixture and endurance. An additional factor to PMMA that contributes to its peak material performance is its aesthetic value, which crosses yet another functional value – its transparency. PMMA is a synthetic and transparent resin, which, when custom designed with, provides easier visibility for surgical installation.

Another speculation as to why the team at Anatomics may have selected PMMA is for its success, is its non-rejection from the human body when implanted. As with all implants, there are many risks in implanting them. Anatomics have selected a type of synthetic resin, polymethyl methacrylate (PMMA), that has been carefully considered and selected for such reasons. PMMA holds minimal residual monomers, which are known to be cytotoxic. This toxicity appears transient, and little, if any significant inflammatory reaction is created by the implant (J.J. Gary, D.L. Mitchell, S.M. Steifel, M.L. Hale 1991). Therefore, the risk of inflammation such as monomer release and damage of dural and sub-dural tissues associated with exothermic reaction is very minimal (Anatomics Pty Ltd 2017).

IMG_0513
Anatomics Acrylic Custom Cranial Implant 2016, 3D Printing & polymethyl methacrylate, photographed by M. Majstorovic, Museum of Applied Arts and Science, Sydney.

Overall, the benefits of PMMA and acrylic implants is that they are dimensionally stable, chemically inert, radiolucent, nonconductive, inexpensive, and can be easily placed and modified (D.N. Firtell, R.J. Grisius 2003). There is also minimal risk of inflammation from bodily tissue, cutting edge technology involved in materials & process, along with the potential to change an individuals life with this life changing medical product.

Processes & Recurrent Evaluations:
The process to produce a work like this is meticulous, extremely detailed and very strategic. As a whole, the process involves an anatomic biomodel of the bone defect for surgical planning and the design and manufacture of the patient-specific implant (Jardini 2014). The concluding step of installation process then involves surgical implantation.

Firstly, before any production, there is a need identified for a cranial implant. In the case of Anatomics Acrylic Custom Cranial Implant 2016, a patient endured trauma to the skull, which required removal of the cranial bone flap. This removal of cranial bone required a fabricated replacement, that ensures optimal size, shape, and mechanical properties.

In short, the design process for this type of work is initially realised by medical imaging which crafts a patient specific implant, to precisely fit the affected area. Anatomics will commence the design process via the program AnatomicsRx, a free to download software that provides steps for CT scan uploads. With this software, individuals can upload their CT scans and request quotes. AnatomicsRx is exceptionally beneficial in designing an anatomically correct biomodel of the bone defect. After the team at Anatomics have successfully designed a pre model and biomodel, teams are able to further review any design implications via a more accessible design software called AnatomicsC3D. AnatomicsC3D is an “interactive online service for surgeons to view CT scan data, to facilitate implant design of complex cases” (Anatomics Pty Ltd 2017).

AnatomicsC3D has been purposely designed to easily integrate design elements between surgeons and implant specialists. Anatomics have really exceeded their intentions of smooth implant development with this easy to navigate feature. Each step of criticism and alteration between the models allows for constant evaluation. There is no software download involved, only a valid email address and internet connection required (Anatomics Pty Ltd 2017) to access it. This allows for joint interaction between the surgeons, other important operators and the individual receiving the medical device.

In more specific details, the design process for an implant by Anatomics Pty Ltd follows a process as such:

  1. Anatomics Pty Ltd will receive the patients CT scan. From this, Anatomics Ptd Ltd can develop a Bone Resection Template (also known as a biomodel).
  2. A suitable date/time for AnatomicsC3D session will be confirmed.
  3. Anatomics sends an invitation via email containing a hyperlink.
  4. At an agreed time, all members will click on the link and view the design screening.
  5. At this time, the surgeon can access the mouse, control the cursor and show/describe key features (2017).

Following the design process is a further BioModel Prototype production. This process consists of the Bone Resection Template (BRT), which is developed to facilitate pre-surgery preparation. This allows for experimentation, trial and error to produce the best possible fit. After, another CT scan is performed on the BRT, which provides Anatomics Pty Ltd a cutting guide and specific instructions for the surgeon. This process also presents another BioModel prototype to test the fit of the cranial implant and surgeon review (Anatomics Pty Ltd 2017). As one can establish, there is plenty of revision and development throughout the design process.

This fantastic opportunity for interaction provides clear and direct insight for all parties involved, especially the patient. It creates a thorough communication channel between patient, surgeons, and affiliates. I speculate that this decision within the design process was made, as it allows specifics to be addressed and continually improved.

The next step in production is developing a working product from PMMA, and pre-drilling specific holes. These pre-drilled holes allow for fluid transfer between the implant and also for ease of attachment and installation (Anatomics Pty Ltd 2016). The bonus of this feature is that it also minimises operating theater time and enables a smooth removal should the implant ever be removed. PMMA is also radiolucent and non-magnetic, which allows for compatibility with post-operative imaging (Anatomics Pty Ltd 2017).

Experimentation with new and existing technologies:
Anatomics have held various experimentation with new and existing technologies throughout the design process. The main area of recorded experimentation by Anatomics is within the collaborative design process and incorporating CT scan technology within their own design software. Experimentations were required to determine the best possible quality of CT scans to ensure the highest possible superior BioModel. As stated in the Anatomics Pty Ltd CT scan protocol, the quality of the CT scan is absolutely crucial for the production of a high quality patient-specific implant or Surgical BioModel (anatomical replica) (2017). Trailing of CT guidelines up against the AnatomicsC3D software determined a set of certain requirements that must be met. If they are not met, then they are not eligible for a custom made implant. These specific requirements include:

  • Orginial files of CT scans, no reformats.
  • Slice thickness of certain parts of anatomy. For the Anatomics Acrylic Custom Cranial Implant 2016, a slice thickness of 1.0 to 1.25 is required, along with spacing of 0.625 to 0.8.
  • Zero gantry tilt.
  • Field of view to only show only the structures of interest to surgeon. For cranial implants patients, this includes the entire skull.

After extensive program software production and analytics, the team at Anatomics determined that these requirements would produce the best possible results. Furthermore, Anatomics has stated that they have firm research, development and commercial partnerships with a number of organisations and universities around Australia and overseas (2017). These partnerships ensure ongoing opportunities to experiment and refine innovative products and materials.

Overall, Anatomics Pty Ltd have been very successful in achieving their intention via the material of the work, design process and ease of implantation for surgeons. PMMA holds several key benefits, including its inexpensive nature, low risk of inflammation to surrounding tissue when implanted, ease of labour when inserted by surgeons and its carefully crafted patient-specific design. The fabrication of acrylic cranial implants via AnatomicsC3D software enables the production of models and implants directly from a 3D virtual model, facilitating surgical procedures and reducing any associated risks (Jardini 2014). The development of a patient-specific implant, as seen by Anatomics Acrylic Custom Cranial Implant 2016, calls for no need for cutting, shaping or mixing during surgery, (Anatomics Pty Ltd 2017) further allowing ease in the operating theater. Constant evaluation is present in all stages of the design process, calling for several alterations in the biomodels. Finally, Patients are given full awareness of the design process which would undoubtedly provide reassurance in surgery, often a wary time for patients. The application of media, materials, and technologies are executed successfully in AnatomicsAcrylic Custom Cranial Implant 2016, making it an outstanding piece of work.

-1861 words-

 

Reference List:

Anatomics Pty Ltd 2016, Anatomics Acrylic Custom Cranial Implant 2016, 3D Printing, polymethyl methacrylate, Museum of Applied Arts and Science, Sydney.

Anatomics Pty Ltd 2016, curatorial statement displayed in Out of Hand: Materialising the Digital exhibition, viewed 27 March 2017, Museum of Applied Arts and Science, Sydney.

Acrylic Patient Specific Implants, Anatomics Pty Ltd 2017, viewed 3 April 2017, < http://www.anatomics.com/applications/cranio-maxillo-facial/cranial-implants/acrylic >.

D.N. Firtell & R.J. Grisius 2003, ‘Preformed acrylic cranial implants using fused deposition modeling: A clinical report’,
The Journal of Prosthetic Dentistry, vol. 90, no. 5, viewed 3 April 2017, < http://www.sciencedirect.com.ezproxy.uow.edu.au/science/article/pii/S002239130300605X>

Jardini A. 2014, ‘Cranial reconstruction: 3D biomodel and custom-built implant created using additive manufacturing’, Journal of cranio-maxillo-facial surgery, vol. 42, no. 8, viewed 3 April 2017, < http://ey9ff7jb6l.search.serialssolutions.com.ezproxy.uow.edu.au/?genre=article&ID=doi:10.1016/j.jcms.2014.07.006&issn=10105182&title=Journal%20of%20Cranio-Maxillo-Facial%20Surgery&volume=42&issue=8&date=20141201&atitle=Cranial%20reconstruction:%203D%20biomodel%20and%20custom-built%20implant%20created%20using%20additive%20manufacturing&spage=1877&pages=1877-1884&sid=EBSCO:ScienceDirect&au=Jardini,%20Andr%C3%A9%20Luiz#?&gt;

J.J. Gary, D.L. Mitchell, S.M. Steifel & M.L. Hale 1991, ‘Tissue compatibility of methylmethacrylate in cranial prostheses: A preliminary investigation’, The Journal of Prosthetic Dentistry, vol. 66, no. 4, viewed 3 April 2017, < http://www.sciencedirect.com.ezproxy.uow.edu.au/science/article/pii/0022391391905182>

‘Polymethyl methacrylate (PMMA)’, in Encyclopædia Britannica, Britannica.com, viewed 3 April 2017, < https://www.britannica.com/science/polymethyl-methacrylate>.

Poly(methyl methacrylate) 2017, Polymer Science Learning Centre, viewed 3 April 2017, < http://pslc.ws/macrog/pmma.htm>.

 

 

 

 

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