Professional Engineering

In 2007 when two people got talking over lunch in a hospital canteen in Springfield, Massachusetts, little did they know where the conversation would lead them. The topic under discussion was surgeon Dr Philip Stoddard’s frustration with the limited and invasive options available to treat babies before surgery to repair cleft palates. He had an inkling that computer-aided design could be the key to improving the process for affected children. 

Listening to Stoddard’s ideas was Beth Roscoe, a medical engineer and prosthetist working at the hospital, who had experience in computer-aided design and manufacturing. Roscoe believed she could help and suggested designing and tailor-making a set of plastic appliances that could fit over a child’s gums, similar to a retainer, for use in the weeks before surgery. The appliances could be made using laser scanning, reverse engineering and rapid prototyping.

A year later the pair’s idea became a reality as a child underwent pre-surgical treatment for cleft palate at the hospital using the appliances for the first time. 

One in every 700 children born in the UK has some degree of clefting in the lip or palate, or both, making it the most common facial birth defect. It is caused when separate parts of the face do not join up properly during development in the womb, leaving a gap in the upper lip and roof of the mouth. 

Children born with a wide cleft of their palate benefit from treatment to narrow the gap before surgery to repair the problem. Pretreating the cleft makes the operation to close the gap simpler and reduces tension on the lip scar, as the tissue is stretched over a smaller area. This gives better results for the child. 

There are two pre-surgical techniques currently used to shrink wide clefts, but both have limitations. One involves surgery to pin an appliance to the roof of the mouth when the baby is one month old. The operation is done under anaesthesia, which carries risks. Once in place, the child’s mother tightens the device by turning a small screw every day. Not only is this treatment invasive, but some doctors say it inhibits growth of the jaw.

The other technique uses a plastic device that is fitted non-surgically to the roof of the mouth. Every week it is removed and reshaped manually by an orthodontist. Weekly visits to a cleft clinic can be time consuming and expensive for families that do not live nearby and the results can vary, depending on the skill of the orthodontist.

Roscoe and Stoddard’s technique uses a series of 12-15 nylon appliances that are changed weekly by the child’s doctor or mother. Each appliance in the series is slightly different from the previous one and they work by gradually moulding the roof of the mouth. With each week the two sides of the cleft become about 0.5mm closer, and over time this reduces the severity of the cleft. Roscoe explains: “It has been very well received because it is easy to administer, it’s not invasive, and it gets the desired result for the surgeon.”