1 June 2021
Heart chamber and laryngotracheal reconstruction, chest and skull correction, removal of hard-to-reach tumours: with the development of 3D printing and design and dedicated professionals with both medical and engineering affinity, more and more surgeries are becoming shorter, more cost-effective, and most importantly safer. How does 3D technology get into the operating room, and how does it transform the surgical routine even today?
Written by Miklós Stemler
Although surgical procedures have undergone tremendous development in recent decades, the human factor - the skills, experience, cold blood of the doctors performing the surgery - is still decisive today. All this can lead to real feats on the one hand and is indispensable in urgent cases (such as post-accident life-saving surgeries) and on the other hand it is a source of error. The latest technological possibilities can help with just that, and here we do not necessarily have to think of surgical robots that are very expensive and would rather fit into science fiction stories for the time being because the silent revolution launched by 3D simulation technology and printing in surgical planning is already in full swing in the operating rooms. With one of the experts on the subject, dr. Balázs Gasz, we looked for the answer to where 3D technology and surgery meet and why this may be important to us.
For most people, a career in cardiac surgery is probably enough, it would even be too much, for dr. Balázs Gasz, associate professor at the University of Pécs Medical School Department of Surgical Research and Techniques and at the same time a biotechnologist 3D designer at the UP 3D Center, however, this was only the first step. The young doctor-3D designer, together with colleagues from different fields of health and engineering, has developed and applied a range of surgical procedures in recent years, but at least as important is the new approach and working method they represent, which can play a key role in the (near) future of surgery.
Beyond the rule of thumb
"There are basically four different ways and stages of the surgical application of 3D technology" - Balázs Gasz introduces the details. "The first is to create a virtual or printed model that shows the individual anatomical characteristics of a certain patient and use these in various difficult surgical procedures, such as removing a tumour in a particularly delicate location." This model can be of great use even during surgery, as in the operating room it allows doctors to remove tumours hidden in risky places, for example near vital organs or neural pathways, without blindly relying solely on their knowledge and intuition.
Through the second method of use, it is possible to practice or individualise surgeries: here a given part of the patient's body, e.g., a part of the skeleton is printed and can be customized during the test surgery, for example the placement of different orthopaedic prostheses, i.e., they do not have to be sized in the operating room during a procedure that is especially burdensome for the patient. The advantages of this are obvious: valuable minutes can be saved for both the patient and the staff, not to mention the much lower risk.
In the next step, the implant made with 3D printing is placed in the operating room. For the time being, it is quite rare for this to be implanted during surgery because it requires very strict material quality standards, but the printed “artificial” implant may be useful in other ways as well. “A given implant, an artificial blood vessel, a model used for bone replacement can be customized and sized for each patient from its own, accepted and customary material. Here we create an external, negative template, based on which the given implant can be designed according to the planned size. So e.g., to replace a bone defect, we use moulds that can be used to form a patient’s personalized implant from standard bone cement. In the same way, a sample can be used in cardiac surgery or vascular surgery to, for instance, tailor the size of a patch to a custom shape and size” - Balázs Gasz has vivid examples.
The recently successfully performed funnel chest correction surgery in Pécs is a good example of when a customized implant made with 3D printing is implanted as well. The surgical procedure, created in collaboration with thoracic surgeons, 3D designers and industry players, takes 45 minutes instead of one and a half hours, has much less potential for error, and thanks to the smooth cooperation, it is slowly becoming a common practice at the Clinical Center in Pécs.
Simulated blood circulation, real heart surgery
In the fourth mode, the object created during 3D design and printing already has a physiological function so to speak, for example, a part of the patient's vascular system is printed and blood circulation is simulated in it. A good example of this is the so-called ventricular reconstruction surgery, in which cardiac muscle tissue that has died during a heart attack needs to be replaced by “patching” the wall of the dilated left ventricle.
The primary risk factor during the procedure is that the heart must be taken out of the circulation during the procedure, and this poses an increasingly serious danger with each passing minute. If the surgeons start to create the patch in the traditional way, after opening the chest based nearly on the rule of thumb, or on the basis of the CT images taken earlier, it can take a long time and success is not guaranteed either, but the researchers and developers in Pécs have significantly reduced this time after realistically modelling patients' hearts during their functioning based on various imaging procedures and they are able to simulate the best functioning patch shape. From this, a template is made that is available to the surgeons before the surgery, significantly reducing the time it takes to exclude the heart from circulation.
So far, three successful surgeries have been performed in Pécs with this method with the participation of dr. László Lénárd and dr. Örs Pintér, and in several cases it was revealed during the simulation that the surgical method cannot be applied to the given patient. All this is also a positive development because it has saved them from a difficult and unsuccessful surgery, and one patient has undergone a successful heart transplant after that.
Similarly, the aim of the cooperation of the Pécs working group with otolaryngologists (Dr. László Lujber and his colleagues) is realistic modelling of organ functions and, thanks to this, the restoration of the original function during the tracheal reconstruction procedures. The issue is of particular concern because of the high number of people who have been mechanically ventilated permanently due to the coronavirus epidemic, as there is a serious risk of their tracheal cartilage deliquescing and therefore requiring restorative surgery. The work is currently in the animal testing phase.
Perhaps the examples above have already shown that, in addition to the technology that is becoming more and more available, a multidisciplinary approach is essential to success. As Balázs Gasz says, doctors working together need to think a little bit like an engineer, and engineers need to think a little bit like a doctor, and this new approach and working method need to prevail in healthcare based on tradition and solid conditions. Thanks to his special career path, according to the experience of the professional from Pécs who sees both fields, the vast majority of doctors are positive about new procedures that facilitate surgeries and even save patients' lives and this is also demonstrated by the wide-ranging collaborations: in Pécs, among others, new procedures have been developed in the fields of neurosurgery, thoracic surgery, cardiac surgery, otolaryngology, orthopaedics and traumatology, but collaborations are increasingly being organized in several parts of the country. The encounter of different visions leads to even more joint thinking and further results.
The next phase of technological development may be the surgical application of augmented reality. The foreseeable future is that the surgeon performing the procedure is provided control by augmented reality goggles during the surgery, outlining the endpoints and typical possibilities of error, and augmented reality and 3D technology may also play an increasing role in education, as successful documentation of interventions will be able to serve as curriculum and practice material. Further educational opportunity is the presentation of the expected results and possible errors of the interventions performed by the surgeons under simulation conditions, based on which the critically important surgical experience can be significantly increased.
In the future, there will be an increasing need for professionals with a hybrid interest and knowledge similar to Balázs Gasz and his colleagues, and this is the aim of the Biomedical Engineering MSc training starting at the University of Pécs in September. And why might it be worthwhile for a healthcare professional to poke his nose into technical matters and an engineering professional to poke his nose into healthcare? According to Balázs Gasz, even only because of the joy of discovery. "There is no greater experience than when we as doctors understand things, as engineers we find methods for it, and then we can offer a common solution - and these then lead to more and more opportunities."