Malaysia’s first heel bone replacement with 3D printed mould
KOTA KINABALU: A team of oncologists from the Queen Elizabeth Hospital here successful performed Malaysia’s first 3D printed moulded calcaneal bone (heel bone) replacement on a young man.
The procedure, using the 3D moulded heel bone, was done on the patient who suffered from a recurrence over a treated Giant Cell Tumour (a rare but aggressive non-cancerous tumour) of his heel bone (calcaneum).
A statement from the hospital on Tuesday said the patient’s recurrence of the tumour was extensive and required a complete resection of the calcaneum that would leave a void over the heel region that was crucial in bearing the patient’s body weight.
Following the operation, the patient was recovering well with his 3D moulded heel bone with no complications developing, the hospital added.
They noted that the 3D printing method for the bone replacement method was “a very efficient and economical option” for patients in view of financial constraints government hospitals had in providing patients with replacement implants.
“Many future patients can benefit from this method of reconstruction – as this method can print and mould any bones in the body as long as the 3D printing can print,” the medical team said.
The team of doctors were from the Orthopaedic Oncology Department of the Queen Elizabeth Hospital I and Queen Elizabeth Hospital II, here.
The preparation and surgery were led by Dr Aaron Gerarde Paul, Dr Eyrique Goh Boay Heong and Dr Tee Kok Keat on January 24.
Chief Assistant Medical Officer Mohd Sukri Umar spearheaded the engineering component of the project with a donated 3D printer.
The hospital said that several weeks of pre-planning was done for the case with brainstorming as well as to iron out and improvise the protocol for the surgery.
They explained that CT images of the calcaneus were downloaded via a software that enables them to convert the images into a 3D model.
The material used is polylactic acid (PLA) – a type of polyester made from fermented plants which later turn into lactic acid.
PLA had a lower melting point than many petrochemical plastics and requires less energy for conversion making it the best choice for 3D printing, they explained.
The mould of the exact shape of the calcaneum was printed and sent for sterilisation via “Sterrad” to rapidly destroy microorganisms.
In explaining further, they said that polymethyl methacrylate (PMMA) also known as bone cement was inserted within the cavity of the printed calcaneum.
“The cement will then harden following the mould’s shape.
The moulded calcaneum is easily removed as the heat dissipates the PLA mould allowing it to peel off like rubber and the moment it is removed, the mould hardens back,” the statement said.
The diseased calcaneus was removed leaving behind the soft tissues, for example tendons that were later sutured to the printed new calcaneus via a prolene mesh, they said.
The newly made calcaneum was then inserted into the cavity with its anatomic fitting and screws were inserted to hold it in place.
“The bone cement is harder and stronger than physical bones, allowing full weight bearing post-operation – however a rest period was ordered to allow soft tissues to incorporate with the calcaneum,” they said.