Patients who lose their ability to speak after surgical treatment for throat cancer may be able to regain that ability much more quickly thanks to a new device developed by researchers at the National University of Singapore (NUS).
A project led by Chui Chee Kiong of the NUS department of mechanical engineering and David Lau, consulting ENT surgeon at Raffles Hospital, reduces a two-week waiting time before patients can speak to about 10 minutes after the initial procedure.
Cancer patients who undergo a laryngectomy and lose their voice box can recover approximately 80% of normal speech by having a voice prosthesis fitted into an opening or fistula between the trachea and esophagus, the researchers noted in a press release. To speak, the patient covers the stoma with his or her thumb and forces air through the prosthesis into the esophagus and out through the mouth.
Before the prosthesis can be inserted, the surgeon makes a small tracheo-esophageal puncture (TEP) in the wall between the trachea and esophagus. During the puncture, a guide-wire is inserted into the fistula to prevent the creation of false passages. Two dilators are then inserted to widen the fistula.
Traditionally, a temporary rubber tube is placed into the fistula and the voice prosthesis was not inserted until about two weeks later. The new device developed at NUS changes this.
"We have merged all the steps into a single procedure," Dr. Chui explained. "Most significantly, although doctors still need the nasal endoscope to guide and monitor progress during the procedure, our system ensures an immediate snug fit of the prosthesis in the passageway created between the trachea and the esophagus."
Voice prostheses vary in length for different individuals, and the length of the TEP needs to be accurate, he noted.
"We added markings onto the cannula used for inserting the prosthesis," said Chng Chin Boon, a research engineer and another member of the development team. "From the endoscopy, we would know the distance between the anterior esophagus wall and the posterior trachea wall, allowing us to size the prosthesis appropriately."
This eliminates a lot of discomfort, such as coughing and gagging, should the prosthesis need to be removed and fitted again if the measurement is not right, he added.
"Most prostheses need to be changed due to wear and tear, and each time the size of the prosthesis to be inserted may differ due to tissue changes in the patient," Chng said. "Our invention will offer patients a more fuss-free system, cutting down time and discomfort. It will also cut down the cost for the patient as the number of procedures is reduced."
The system has been successfully tested on animals and is now ready for human clinical trials, the researchers said.
