INNOVATION ARTICLES THE IDEA SUBMISSION PORTAL FROM MEDTRONIC

A team of doctors from Spain and Italy have created a functional and adaptable 3D chest wall implant for an athlete who had to undergo a chest wall resection.¹ Postoperatively, on day one of the implant, the patient had normal respiratory chest wall movements; on day 11, he was discharged; and at the 6 month follow-up, the patient was back to jogging and biking. The researchers hope that their designs will help patients who have high physical demands and require a quick recovery with low risk of complications.

There are several reasons why someone may need part of their chest wall cut away -these may include injury and trauma, or, most commonly, an aggressive tumour that is invading the chest wall. Depending on the type of tumour and its location, chest wall resection can involve the removal of soft tissue, cartilage, or bony structures like ribs or the sternum.² 

Considering respiratory chest movements

Each chest wall reconstruction must be specific to each patient, as it depends on the tumour, location, and what tissue or structures that have been removed. Traditional chest wall reconstruction options after invasive tumours include standard metal implants or hardened biocompatible meshes. Often surgeons must use these materials creatively “on the go” to solve specific reconstruction needs.¹ But the field is moving forwards, the first ground-breaking 3D chest wall implant was placed in 2013 for a 62-year-old woman with breast cancer that invaded the chest wall.³ 

“Results with these approaches are good but, sometimes, not enough for patients with moderate to high physical demands due to the inherent rigidity and one-fits-all designs”, said Dr Javier Moradiellos, Thoracic Surgery Department, Quioronsalud-Madrid University Hospital, Madrid, Spain.

“For the first time in chest wall reconstruction, our innovative design involved biomechanical principles,” said Moradiellos. Their implant was specially designed to focus on respiratory function, considering the expected expansion and contraction of the rib cage as well as the ideal rigidity and flexibility at the anatomical structures.

The research team designed and created a personalised titanium model for a competitive male athlete, aged 32 years, with a rare and aggressive carcinoma that was invading his chest wall. Together with biomedical engineers on the team, they obtained precise measurements from assessing chest CT scans of the patient. The scientists chose titanium for its biocompatibility, flexibility and durability properties. 

The design considered controlled respiratory displacement of the implant and allowed for osseointegration - or growth of new bone tissue into the implant, which reinforced coupling to the chest wall. The design incorporated a ‘Greek wave’ folding pattern of the titanium, which would act like a functional spring or hinge, to allow for physiological expansion and contraction of the chest wall during respiration.

Follow-up and results

After the last cycle of chemotherapy, the patient had surgery to remove the tumour and associated parts of the chest wall, and then the implant was put in place. An artificial pleural membrane (a membrane that lines the surface of the lungs and the inside of the chest wall), made with polytetrafluoroethylene, was also attached into the chest. 

The research team were relieved to see that immediately after the procedure, chest wall movements were symmetrical and there were no complications. The athlete was discharged at day 11. After 6 months, respiratory movements showed synchronic, coordinated movement of the native chest wall and the integrated implant. The patient was able to continue with jogging and biking. “He had a great recovery and he is back to almost normal physical activity”, said Moradiellos.

Next steps

Dr Moradiellos explained that they have been working closely with a group of biomedical engineers from the Technological Institute of Canary Islands (ITC). “This multidisciplinary approach is essential to integrate both the surgical demands in each case and the technical know-how into an effective, functional, long-lasting implant. This collaboration has already proven fruitful and we expect it to continue in the future with more refined and advanced solutions for our patients”, said Moradiellos.

As the implants are personalised for each patient, the regulation hurdles are low, explained Moradiellos. Patients with fast-growing tumours need a quick and available solution, so 3D-implanted implants are ideal. “The surgeon is responsible for the indication and performance of the device, and the design and manufacturing company is responsible for the printing quality and the expected behaviour of the implant, after a finite-element analysis”, explained Dr Moradiellos.

The team have other patients on the horizon for whom they will be designing customised 3D-printed titanium chest wall implants, and they are currently considering more advanced designs.

The team hopes that this approach will allow for more options with rapid and aggressive tumours of the chest, while restoring both the function and structure after a chest wall resection. “As an oncologic surgeon, I strive for adequate removal of the tumour and relapse-free survival. As a thoracic surgeon and medical doctor, I must think about recovery and about regaining lost function. I must think about a life for my patients in which they hardly remember they had a 3D-printed titanium structure implanted in them. The ideal of a fully functional chest wall implant is what drove my team towards this path, with the aim to provide our patients with increasingly better solutions for their reconstructive needs”.