In the field where innovation can help save lives, 3D medical printing is a very promising technology that can empower healthcare providers and medical researchers. The use of 3D printing technology has been around since 1980, but has only recently been used in the field of medical science.
There are many established applications of 3D medical printing. It is commonly used to manufacture hearing aids. In fact, there are more than 10 million 3D printed hearing aids that have been produced and distributed worldwide. 3D printing is also used in creating dental implants. However, there is more to 3D printing than making hearing aids and dental implants. Recently, medical researchers and doctors have developed innovative new uses for 3D printing. This article will provide an in-depth discussion of these uses, specifically in surgical planning.
3D Printing of Orthopedic Implants
Osteotomies are among the most common orthopedic surgical procedures performed. This procedure corrects the deformities of the bone by cutting the bone and resetting it to a better position. This is performed on people who have misaligned joints. The osteotomy then reduces degeneration of the joints, further reducing pain and discomfort for the patient.
3D medical printing can be very beneficial in orthopedic cases. There are many surgical procedures that benefit from 3D printing. Probably the most useful applications involve 3D printing of implants. Orthopedic surgeries can now be performed using 3D modeling and creation of 3D printed osteotomy plates that can be easily and accurately implanted to the affected area. One of the breakthrough uses of 3D-printed osteotomy implants was produced by 4WEB Medical, where an internal bone fixation structure was created for patients suffering from deformities requiring Evans lengthening osteotomies and correction of hallux valgus and cotton opening wedge deformities.1 The new implant provides structural support to the affected part after the operation thus it can sustain the correct angle of the foot and ankle after the surgery.
3D Printing In Cardiac Surgery
Cardiac surgeries are one of the most complicated of all types of surgeries. The use of advanced imaging techniques and 3D printing during preoperative planning is very helpful in improving the result in some operations. The advantage of using a 3D model is that it allows surgeons to study structures inside the heart that are difficult to visualize with conventional 2D imaging.2
The use of 3D printing in cardiac surgery is uniquely beneficial for children because their hearts are small. Given this small size, conventional imaging makes it difficult for surgeons to determine the actual structure of a patient’s heart beforehand. It is often not possible to precisely diagnose structural abnormalities until surgery is already underway. While with 3D printing technology, even the tiniest of heart structures can be enlarged and studied in depth, eliminating a huge proportion of unexpected complications. Proper preoperative diagnosis and planning also reduces the length of the actual surgery.
Patients at the Children’s National Medical Center in Washington DC have benefited from 3D printing; when 3D printed models were used for preoperative planning prior to surgical correction of rare heart conditions.3 Doctors were able to create a 3D model of the patient's heart using hard and soft plastics. The exact replication of the structural abnormalities in the models allowed doctors to visualize and plan their surgeries in great detail before actually stepping into the operating room.
3D Printing In Brain Surgery
The main issue that makes brain surgery difficult is the fact that the brain is housed inside the hard and protective skull. Furthermore, the brain is very delicate, and a successful surgery requires exquisite care.
3D printing has improved brain surgery by aiding development of new and innovative surgical tools, and allowing creation of patient-specific models prior to surgical treatment. In China, doctors created a 3D printed model of a patient’s skull and brain to plan removal of a skull base tumor. The model created by Dr. Li Xuejun from the Xiangya Hospital, gave a clear and tangible representation of the patient’s brain tumor. Surgeons were able to plan and practice the precise path of surgery prior to the actual operation.4
3D printing can also be used to create customized tools for brain surgery. Mechanical engineer Eric Barth developed a tool using 3D printing for epilepsy surgery. A pneumatic drill was developed with a needle attached to it. The pneumatic drill makes it possible for doctors to perform a minimally invasive treatment for epilepsy. The benefit of using the 3D printer to make the pneumatic drill is its low cost; thus making this tool more accessible and available to many medical institutions.5
3D Printing In Lung Surgery
The type of surgery involving the lungs is called thoracic surgery. It encompasses the organs such as the heart, lungs and the thoracic vertebrae. Although 3D printing is often used to help doctors perform surgeries for the heart and brain, a groundbreaking procedure was developed by surgeons from Kyoto University involving lung transplant.6
The patient, suffering from interstitial pneumonia, required a new lung from a donor. The doctor needs to excise part of the healthy lung of the donor and transplant it into the patient. Conventional lung transplant requires the patient to wait for a donor to donate the entire lung. What makes this surgical procedure ground breaking is that the surgeons opted to perform the surgery by transplanting only the lower part of the donor’s lung, which is something that hasn’t been done before.
To help the surgeons during surgical planning, doctors used a 3D printer to create an accurate model of the chest cavity of the patient. The use of 3D printed models allowed the doctors to match the blood vessels and airways of the patient to the donor, thus contributing to the success of the operation.
3D Printing In Thoracic Vertebrae Surgery
Another surgical procedure that benefits from 3D printing is thoracic vertebra replacement. Doctors from the Zhejiang University School of Medicine in Hangzhou, China, conducted the surgical procedure on a patient with a rare bone tumor called an ossifying fibroma. The tumor was located on the spine and specifically affected the vertebrae.7
Surgery on the spine can be risky because removal of the tumor can leave the spine with less mechanical support, contributing to increased stress on the spine and accelerated degenerative arthritis. In most cases, patients who undergo this procedure may experience permanent damage on their vertebrae. Doctors used 3D printed models of the patient’s spine to determine the exact anatomy of the patient. Then the surgeons created customized 3D printed titanium implants to provide support to the spine to minimize deterioration after surgery. Titanium was used by surgeons because it is biologically inert and does not react with the immune system.
3D Printing In Kidney Surgery
Recently, doctors have used 3D printing to help treat patients suffering from cancer of the kidney. As presented at the Association of Urology Congress in Sweden, Japanese researchers were able to develop a 3D model of a kidney to simulate cancer surgery.8
Using a 3D printer that injects clear polymer material, doctors were able to create an accurate model of the kidney so that they can study the blood flow and detailed anatomy of the patient’s kidney. The model also allowed the surgeons to determine the margins of the tumor. The 3D printed model was made from transparent material, allowing doctors to easily see the blood vessels inside the kidney model. They based the 3D model from the 3D imaging created by CT scan and MRI.9
3D Printing In Hip Surgery
There are many medical accounts that have shown success of 3D printing in treating patients who need hip surgery. One of the successful uses of 3D printing in hip surgery was performed by surgeons from the Southampton University Hospital.10
Orthopedic surgeon Dr. Douglas Dunlop used 3D printing to create customized titanium screws that are more durable and can match the exact measurements of the patient’s hip. The procedure was very innovative as stem cell therapy was also used as adjuvant to the treatment. While the 3D printed titanium screws are used to keep the hips together, the stem cells can help regenerate bones thus helping the patient to walk again with ease.
3D Printing In Throat Surgery
Babies born with weak tracheas can benefit from 3D printing. Doctors from the University of Michigan fitted two babies who suffer from constant suffocation because they have weak tracheas—a condition called tracheobronchomalacia. The babies constantly need a ventilator to breathe. Conventional methods of treating babies with this condition can put the babies at extreme risk.
Biomedical engineer Dr. Scott Hollister, together with his team, created a splint to open the airway of the babies allowing them to breathe. Hollister used a 3D printer to create a bioresorbable scaffold, that is similar to a vacuum cleaner hose, which was surgically implanted to the chest of the babies to hold the trachea open.
Before the doctors performed the surgeries, 3D printed models of the wind pipes of the infant patients were created. The models give doctors the ability to study the windpipes preoperatively, and allowing them to determine the best location to surgically place the splints.
The doctors revolutionized the technique even further by creating the 3D printed splint using materials that can be broken down and absorbed by the body. This helps minimize the need for further surgical procedures to remove the splint, and also reduces the risk for infection and complications. Three weeks after the operation, the two babies were taken off the ventilator.11
The 3D printing technology has many benefits for surgical planning. This technology looks very promising and many innovations are reported each year that help doctors perform complex surgical procedures while reducing risk to patients and improving outcomes.