Replacing damaged vocal cord tissue with implanted new tissue engineered from vocal fold mucosa that is similar biologically and physiologically to that of native human tissue may one day offer a new surgical approach to restoring the voice in people with severe vocal cord damage.
Although much more work still needs to be done to develop such an implant for humans, researchers are well on their way. Findings from a recently published study show that new vocal cord mucosa capable of making sound can be engineered in the lab from purified primary vocal fold fibroblasts and epithelial cells taken from human donors.
The study also found that, when transplanted in mice, the engineered vocal cord mucosa was not rejected.
“The engineered tissue was able to generate normal-like voice output,” said senior researcher of the study, Nathan V. Welham, MD, PhD, with the division of otolaryngology-head and neck surgery, department of surgery at the University of Wisconsin School of Medicine and Public Health in Madison. “[The engineered tissue] was also well tolerated by the human adaptive immune system in a transplantation situation.”
According to Dr. Welham, these findings suggest a potential new treatment for patients with severely damaged or missing vocal fold mucosa for whom no treatment is currently available. These patients include those who experience severe tissue damage after undergoing glottis cancer resection, repeat recurrent respiratory papillomatosis (RRP) resection, and with severe vocal fold scarring.
“The best solution [for these patients] might be to completely replace the tissue with an engineered material,” he said, emphasizing that substantial more research is needed before this becomes a viable treatment option.
One issue that needs further investigation, according to authors of a commentary on the study, is healing after implantation.
Emphasizing that vocal folds have unique stresses that affect wound healing, otolaryngologists Jennifer Long, MD, and Dinesh Chhetri, MD, underline the possibility of the development of scar tissue forming in the implant that would then again impair the voice and make the implant virtually futile.
“Identifying those features of an implant that minimize scarring during wound healing is critical for clinical application of this emerging technology,” they write.
If further research does show the safety and efficacy of vocal cord implantation, they propose that implantation should be considered at the time of laryngeal cancer resection.
“This single-surgery scheme would dramatically change the approach to vocal fold cancer treatment and voice rehabilitation,” they write.