New technology developments have enabled healthcare advances in 3D printing with an estimated $6.08 billion by 2027 in terms of software, hardware, services and materials. The technology has given a boost to customized medicine, allowing a more accurate understanding of patient symptoms and treatment, and generating increased efficiency in the operating room (OR). Advent of 3D printing technology is leaving its mark in specialties such as orthopedics, pediatrics, radiology and oncology, as well as in cardiothoracic and vascular surgery.

Doctors, hospitals and researchers around the world are using 3D printing for:

• preoperative planning and customized surgery.
• medical devices and surgical instruments.
• molds, prostheses and customizable implants.
• 3D digital dentistry and drug administration.

1. Preoperative planning

3D printing allows specialists to create reference models using MRI scans and CT in order to help surgeons prepare better for surgeries.

In 2016, a child in Northern Ireland had two unhealed bones injuries his forearm. The child could not rotate his arm more than 50% and was suffering from increased pain. CT scanning and X-rays showed deformed bones, and the treatment required an osteotomy – a four-hour invasive surgery in which the surgeon reshapes the bones to improve rotation. However, the surgeon, printed a 3D model that changed the diagnosis, the surgical intervention and the recovery of the patient:

• It was the tight structures between the bones and not the shape of the bones that limited the child’s rotation ability.
• The procedure was completed in less than 30 minutes, instead of four hours.
• The patient was able to gain 90% arm-range movement four weeks after the intervention.
• The recovery time, the post-operation pain and the scarring decreased considerably.

Such 3D printing is changing preoperative planning which translates into less time spent in the OR, better surgery outcomes for the patients, faster post-op recovery and lower costs for hospitals.

2. Customized surgery

Due to decreased costs of 3D printers and increased availability of CAD/CAM medical software, more hospitals are creating in-house 3D-printed anatomical models. The process entails several steps:

• MRI and CT scans are processed in a stage known as segmentation.
• Each organ and body part type is modeled.
• Models are translated into STL file formats, arranged for printing and sent to the 3D printer.

Rady Children’s Hospital created its own 3D Innovations Laboratory for printing 3D models, including models that mimic human tissue such as airways, hearts and bones. In 2019, the hospital admitted a 7-year-old child born with a single functional heart ventricle (instead of the normal two). The medical team created a 3D-printed model that detailed every vein, artery and valve of the child’s heart, which enabled surgeons to identify the location where blood flow needed rerouting.

Anatomical models that are 3D-printed enable surgeons to plan the operation efficiently and establish better treatment solutions, decrease the operation's duration, and improve research and training for medical students.

3. Designing medical devices

In order to serve their purpose, medical devices must meet several requirements:

• They need to comprise the perfect balance in terms of size and weight.
• The must match the particular shapes of the human body.
• They have to be functional, and they have to pass specific endurance tests.

Producing medical device to meet these criteria traditionally required extensive time. The alternative found by medical device manufacturers was stereolithography – a process in which a moving laser beam controlled by computer builds the required structure layer by layer. Thus 3D printing has been used to create the prototype of an inhaler, including the needed fixtures and jigs, aiming to:

• Reduce production from one to two weeks to one to two days.
• Reduce cost 90% (from £250 to £11 or $343 to $15).

4. Improving surgical instruments

Customized 3D-printed surgical instruments such as scalpel handles, forceps or clamps help surgeons perform better in the OR, reduce operating time and promote better surgical outcomes for the patients.

Manufactured from materials such as stainless steel, nylon, titanium alloys or nickel, customized surgical instruments are well suited for sterilization. Endocon GmbH – a German medical device producer – has used metal 3D printing to create an alternative surgical tool for hip cup removal. This is traditionally a 30-minute procedure performed with a chisel, but the chisel can sometimes damage the tissue and bones, which results in an uneven surface, making the insertion of a new hip implant difficult.

Endocon’s stainless steel alloy 3D-printed blades, called endoCupcut, enabled precise cutting along the acetabular cup in three minutes and decreased the rejection rate for the replacement, while reducing production time and cost.

5. Creating prostheses

While simple prostheses are available in predefined sizes, customized bionic prostheses cost thousands of dollars. This situation affects many children who outgrow their prostheses and need customized replacement parts, which are produced by a handful of manufacturers.

In 2016, Lyman Connor and Eduardo Salcedo created the Lyman’s Mano-matic prosthesis to provide bionic prosthetics to those who need them and cannot afford them. Globally, prostheses designers can use 3D printing to overcome the financial obstacles and time line constraints entailed by this process. The costs of this manufacturing method are significantly lower than traditional methods, and the prostheses are ready in approximately two weeks, making 3D printing a viable solution for customized bionic devices that replicate a human limb's motions and grips.

6. 3D-printed implants

Metal 3D printing enables medical devices designers to produce implants that perform better, match better and last longer, for knees, spine, skull or hips.

Electron Beam Melting (EBM) is a technology that melts a metal powder layer by layer with the help of an electron beam, thus generating high-accuracy parts. These orthopedic implants provide spongy structures that mimic regular bone tissue, resulting in a higher percentage of osseointegration – the in-growth of a bone into a metal implant.

In 2016, a patient suffering from a tumor that eroded five of his vertebrae was admitted to Peking University Third Hospital. The tumor, caused by a rare form of malignant chordoma, could be removed only through surgery. However, the healing of the extended size bones defects might not have been completely and correctly possible once the lesion would have been removed.

To address this challenge, researchers designed five artificial vertebrae similar to the body structure of the patient using EBM technology. The prosthesis enabled increased stability of the spine, reducing pain and increasing the durability of the device, which allowed the patient to walk without braces two months after the surgical intervention.

Customized 3D printed implants represent a flexible solution for difficult orthopedic cases and may generate more treatment opportunities in the future.

7. 3D Digital Dentistry

A recent report indicates that, by 2022, cumulative manufacturing will produce around 500 million dentistry devices and restorations every year, with an estimated $9 billion for the entire dental segment by 2028.

In the dental industry, 3D printing is used for the manufacturing of dentures, surgical guides, bridge models and, most of all, for clear aligners – invisible devices that straighten teeth.

Compared to metal braces, clear aligners are actually invisible and can be taken off when the wearers need to brush their teeth or eat. The traditional production method of clear aligners is a combination of manual and milling processes that requires time and effort. The 3D printing technique speeds up the process, since customized molds for clear aligners can be manufactured directly from digital scans of patients.

Looking for cost-efficient solutions, one dental start-up has perfected an easy process to produce molds for clear aligners:

• Customers take impressions of their teeth with an at-home impression kit or an intraoral scan at a specialized center.
• Impressions and scans are checked by a dental professional, who creates a plan for treatment.
• The company then sends the 3D-printed aligners to the customers.

Therefore 3D printing is a cost-effective method to produce clear aligners, since the setup and tools are not expensive, and their customization is, as proven, direct and simple. 

8. Streamlining drug administration

3D printing can also simplify drug administration with the help of 3D-printed pills. Polypill is a concept designed for patients suffering from several affections, containing five different drugs compartments and two separate release profiles.

Patients affected by several health issues often take their medication at different hours within the day, and this can be confusing in setting a schedule. This 3D printed pill handles both medication dosage and potential interactions between drugs treating different conditions, so eliminating the need for this scheduling and close monitoring.

The administration of a single customized pill to treat several ailments has multiple advantages:

• increased medication adherence to prescribed treatments.
• customized medication or drug combinations.
• lower production costs, due to the ability to treat more affections at the same time.
• greater accessibility in developing countries to affordable and efficient drugs.

Conclusion

As the price of high-performance 3D printers decreases, more medical professionals use 3D printing to produce cost-efficient customized devices in short periods of time, to design patient-tailored anatomical models, to identify revolutionizing clinical solutions and to create new treatments adapted to patients’ needs.

The advances in 3D-printing technology will attract more customized care and more high-precision medical instruments. At the same time, 3D printing is expected to make an impact in other medical specialties such as ophthalmology, regenerative medicine and bio-printing.

About the Author