Cancer of the larynx is treatable, but it sometimes requires removing the larynx altogether, leaving the patient unable to speak. There are, however, vocal prostheses that can be implanted to restore the patient’s speech. Unfortunately, these prostheses are expensive and tend to need frequent replacement. So South Ural State University student Nikita Dubrovsky is working on an alternative.
“Everywhere in the world, the method being chosen for vocal rehabilitation of the patients who underwent laryngectomy is the voice prosthetic care,” said Dubrovsky. “Most often abroad-manufactured apparatus are used which allow patients to recover their voice. But the big minus here is that such an apparatus is due for replacement after approximately just one year. Imported prostheses are quite expensive, so we decided to come up with our own development, which will feature similar technical characteristics, but will be much cheaper.”
Vocal prostheses first began being used in 1980. A shunt is placed between the trachea and upper esophagus, and a valve is implanted into the opening. This valve allows for the exhalation of air from the trachea to the esophagus, which creates vibration in the walls of the esophagus and the lower pharynx, generating sound. These valves have more than one drawback, however.
“The abroad-manufactured prostheses mostly use plastic, which is very inconvenient because it’s hard,” explained Dubrovsky. “We’re planning on using food silicones, which will make the prosthesis softer, and patients will less suffer from pain. The forms for drip moulding, which we will be filling with silicone, will be manufactured using 3D printing.”
A 3D model of the vocal prosthetic was created, and scientists at the SUSU Research Center for Sport Science have used SLA 3D printing to create a prototype, which will be sent for clinical testing at the Chelyabinsk Regional Center for Oncology and Nuclear Medicine.
“Unfortunately, when we were working with 3D printing, we faced damages that occurred in the drip-moulding tank in the process of the model creation,” said Dubrovsky. “Moreover, such process of production may take 12 to 24 hours, which is a very long time. Since 3D printing turned to be not that accurate, we will probably have to give it up in the future and turn to lathe operators instead, as they are in command of high-accuracy equipment. But first we need to improve our computer model.”
Dubrovsky and his fellow researchers will continue work on the implant as Dubrovsky continues work towards his Master’s degree; he just graduated with a Bachelor’s in Physical Education. They will work on finding food-grade silicone of optimum hardness for patient comfort.
Dubrovsky’s work is potentially good news for the future of patients who require larynx removal; unfortunately, this week also brings some bad news for Italian surgeon Paolo Macchiarini and his patients. Macchiarini published a paper in 2011 in the medical journal The Lancet regarding an artificial windpipe he had created that was coated with the patient’s own stem cells, which would then develop into mature tracheal cells that would not be rejected by the patient’s body. It sounds like a groundbreaking development in bioprinting, but it turns out that the procedure was worse than ineffective.
Macchiarini and colleagues performed the procedure on a total of eight patients, seven of whom died. The surgeons lost track of the eighth. Macchiarini was associated with the Karolinska Institute, which awards the Nobel Prize in medicine every year. In 2014, several surgeons at Karolinska filed a complaint alleging that Macchiarini had downplayed the risks of the procedure, and that it had been carried out on at least one patient who had not been critically ill at the time.
Recently, the new President of the Karolinska Institute, Ole Petter Ottersen, requested that The Lancet retract two papers published by Macchiarini, and the journal obliged, as explained in a recent editorial. The Lancet is a prestigious medical journal that only publishes work after extensive peer review, so such a retraction is extremely rare.
“No ethical permit had been obtained for the underlying research,” said Ottersen. “The research was carried out without sufficient support by preclinical data, and the paper presents its data in a way that is unduly positive and uncritical. The clinical findings reported are not supported by source data.”
Macchiarini and his co-authors were found guilty of misconduct, and two members of the Nobel medicine prize assembly were forced to step down.
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