3D printing is likely to open a new avenue for accurate surgical planning and simulation for foot and ankle surgeons, say Dr Vaibhav Bagaria, Senior Consultant – Joint Replacement & Sports Surgeon, CARE Hospital & ORIGYN Clinic and Lopaa Bagaria, Product Manager – 3D Printing, Timeless Innovation Labs.
Many of us may have heard this interesting piece of news coming right from the International Space station. In a unique feat, the ISS was able to install a 3D printer in zero gravity and successfully printed objects that may be used as spares and replacement required to keep ISS operations going on smoothly. The development is also touted as a stepping-stone for establishing manufacturing hub in outer space. Richard Branson and President Obama were not far off the mark when they touted as 3D printing as one of the most exciting invention of the century that can transform the entire human activities and perceptions. While all the attention was focused on the high tech sphere, a rapid turn of event ensured that the revolution was quietly turning a new page in the medical innovation and transforming the way surgeon practice.
The conventional ways to ensure preoperative planning and postoperative assessment in field of medicine was to use the radiographs. In complex cases many surgeons used CT scan and the 3D reconstruction using specialized software. A recent addition to these existing techniques is prototyping or 3D modeling. In view of their ability to be specific to a patient, they are also called as patient optimized surgical tools or POST. The process involves converting the CT scan images into a machine printable language. These inputs are then transmitted to a 3D printing machine, which using additive manufacturing technology creates a life-sized model.
Surgeons are increasingly using 3D POST – Patient optimized surgical tool in diverse fields such as orthopedics, joint replacement, maxillofacial surgeries, neuro, and spine surgery. In orthopedics 3D POST is used in the management of complex primary hips, fracture, and revision cases. In a series of cases reported by the authors this indigenously developed technology was used in case of complex hip surgeries and fracture treatment. All the complex cases had their CT scan done based on which the 3D printing was conducted.
These models were then used for surgical simulation preoperatively and as reference intra-operatively. These models proved to be of great help in pre operative planning, reducing surgical time blood loss and improved post op outcomes. In complex cases such as difficult primaries and revision condition, 3D POST helped in proper inventory planning, and also aid in deciding and sculpting bone grafts. When done postoperatively, they can provide valuable information about the component positioning. The technique also provides data to develop patient specific instruments and implants similar to those popular in knee arthroplasty.
Types of 3D Printing
Fused Deposit Modeling
This is the most common technology available to surgeons and is also called as additive manufacturing. In this method, a spool of the thermoplastic substance is inserted into an extrusion head that heats this material into a semi solid state. The extruder head then extrudes this semi solid thermoplastic or similar material. Specialized software converts the axial image into a machine printable language that the machine presents layer by layer as a replica of the axial cuts.
Direct Digital Manufacturing
In this case the device directly creates the end product. This printed product is ready to use as the machine prints the material that is fit for the end use. In case of medical field it could be the implants made from innovative materials like titanium, tantalum and also bio ceramics like hydroxyl apatite and Tri calcium phosphate. Having this technology at hand ensures a customized product for patient; this could be wedges, spacers, prosthesis or artificial bone for defects. The enthusiast for the technology believes that in future most prosthesis and implants available would be made using this technology.
This technology helps to create highly precise parts and has added advantage because of its ability to combine different materials and different colors. In a way similar to the inkjet printers employed in day to day life, these printers can help create models with over 1000 physical properties and colors
Key Areas where 3D printing is likely to Play Important Role in Surgery
A real life size model ensures that the surgeon can get a look, feel of the disease pathology in the entire 3 dimension. This is especially useful for orthopedic surgeons, joint replacement surgeons, cardiac surgeons and maxillofacial surgeons. The technology has especial use for oncology surgeons who can plan optimal resections and reconstructions.
As a next step the surgeon can not only plan but actually execute the surgical steps on 1: 1 model of the patient. They can choose correct implant, define their placement and also look for an possible errors. Something like a heat phase of any race, it familiarizes the surgeon to what they can anticipate once the patient is opened up.
The model can be sterilized and kept on operating table. The model can serve as ready reference when ever the surgeon is trying to accomplish a critical step. They can compare the actual pathology and surgical plans on this model.
Surgeons can plan for the implant – routine as well as specialized. This reduces the work of OR staff, increases turn over time of the operation room and also reduces infection rates and improves over all system efficiency.
The technology has made great headway in designing patient specific instruments. Once the planning and simulation done at the back end office, appropriate Jigs and cutting tools can be made using rapid prototyping. Several other companies have aggressively taken this and several proprietary devices are currently available internationally.
The day is not far that instead of one size fits all implants, there would be implants tailor made for an individual and for specific pathology. Not only will this increases the life of the implant, offer better kinematics but also ensure that natural non-damaged parts are retained.
Traditionally medical students will learn normal anatomy on cadavers. However this technology enables to study the diseased, fractured part on real time basis. The surgical residents will benefit form the ability to preoperatively simulate the surgery on these models.
Forensic and Crime investigation
The crime investigation is all set to get a flip with this technology. The crime investigators can reproduce and reconceive the crime scene and the injury pattern using 3D POST.
3D printing is likely to open a new avenue for accurate surgical planning and simulation for foot and ankle surgeons. These models can also prove to be a valuable teaching tool for students and residents. The future developments in the field can be in form of designing patient/ disease specific instruments and implants. The working group believes that the technology is likely to play important role in joint replacement, orthopedics, tumor resection and also cranio maxilla facial surgeries.