‘Do no harm’ is the first rule of healthcare, but currently it is an unavoidable necessity for some patients who need jaw reconstruction surgery. Now a new approach is currently in development that aims to save patients months of painful rehabilitation. Clinical Associate Professor Goh Bee Tin, Deputy Director (Research & Education) and Senior Consultant, Department of Oral & Maxillofacial Surgery, National Dental Centre Singapore shares more about her research.
You have been doing research into jaw reconstruction for close to 10 years. What keeps you going?
We need to find better and safer ways to reconstruct the jaw because at present we actually have to harm healthy parts of the body to help patients heal. Let me share what our patients currently go through using a real case as an example. Ms A. was in her 30s when she was diagnosed with a jaw tumour. As it was relatively large, we needed to remove half of her lower jaw. For a young lady who was planning to get married soon, she was terrified! The whole operation lasted 12 hours as we had to take about 10 cm of bone from her leg for the jaw reconstruction as well as graft some skin to cover the wound in her jaw.
Such long complex surgery carries the risk of excess blood loss and infections. Thankfully Ms A. suffered no complications but the recovery took months and was a painful process. The bone graft in her jaw took about six weeks to heal, during which she had to transit from liquid to soft food before she could eat normally again, but recovering from the leg surgery took much longer.
For the first week after her operation, Ms A. was hospitalised and unable to put any weight on her operated leg. She was totally reliant on others for simple daily tasks such as getting out of bed and going to the toilet. For six weeks after her discharge she was still unable to walk because she could only put partial weight on her leg. Ms A was determined to recover well. She attended all her outpatient appointments and was disciplined in doing the physiotherapy exercises she had learnt in hospital. She gradually regained strength and three months after her operation, she was able to walk again.
Today, after one and a half years, I'm very glad to say Ms A. is 'back to normal' and happily married. She is free from the tumour and her reconstruction surgery healed well, although her foot feels weaker than before. Her face looks balanced and 'normal' and she can eat regular food by chewing on the other side of her mouth. However the scar that runs from the top of her calf to her ankle will be an unwelcome reminder of her tumour for years to come. Due to the unsightly scar, she now avoids wearing skirts totally.
Tell us about your research.
We have previously collaborated with Nanyang Technological University (NTU) to ‘grow’ bone to support dental implants. Why is there a need to ‘grow’ bone? If a tooth has been removed for some time, the bone surrounding it shrinks. Therefore, a bone graft may be needed before the implant can be fitted. Usually the bone is taken from the jaw, but if there isn’t enough, it may be taken from the hip or leg, which is painful for the patient.
To avoid this, the team developed a 3-D polymer mesh scaffold that fits snugly into the tooth socket and encourages bone to grow. Clinical trials on patients are underway and this scaffold has recently been approved by Health Sciences Authority.
Building on this idea, we are now working with NTU researchers to apply this technology to grow jaw bones that are customised to patients’ CT scans for jaw reconstructions. It is much more challenging because the jaw bone is larger; the bone needs to be partially ‘grown’ in the laboratory before it can be implanted.
To do this, cells from various sources, for example the patient’s hip bone marrow, are injected into the mesh. Growth factors trigger the host cells to multiply, resulting in bone cells growing on the mesh to form bone. The scaffold is placed in a bioreactor which contains all the nutrients necessary to promote cell growth until it has developed sufficiently to be implanted in the jaw. Blood vessels also need to be grown to supply nutrients to the bone cells in the middle of the jaw bone.
What is your biggest hope as you pursue this area of research?
Treating a patient is more than just saving his or her life. It is about doing our best to help them minimise pain, cost and complications as well as enabling them to rebuild their lives after major surgery. If we are able to successfully ‘grow’ bones for jaw reconstruction, patients will no longer need their leg bone harvested for the bone graft. This will result in safer, less costly care and a much shorter recovery period. It will cut the surgery time from 12 hours to 5 hours, reduce the risk of blood loss and infections, and patients will no longer need to endure months of rehabilitation learning to walk again. This will greatly ease the physical, mental and emotional suffering our patients currently face and enable them to get back to their ‘normal’ lives much sooner.
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