© BSIP/UIG/Universal Images Group/Getty

Research Highlight | 4 July 2017

Regenerative fix is music to the ears

A growth factor helps repair ruptured eardrums without invasive surgery

A non-invasive procedure for repairing eardrums developed by doctors at Japan’s Translational Research Informatics Center could replace the need for surgery.

The treatment only uses topical anesthetic, off-the-shelf medical apparatus and a growth factor to promote the body’s own healing processes. The whole process generally takes less than half an hour.

Shin-Ichi Kanemaru and his colleagues at Kitano Hospital and Kyoto University have administered the therapy to around 400 patients with ruptured eardrums, or tympanic membrane perforations as they are medically known. Their success rate is about 80 per cent — allowing four out of every five patients with holes or tears in the eardrum to avoid surgery, a much riskier treatment.

 “Our new procedures for regenerative treatment of the tympanic membrane reduces the need for invasive surgeries,” says Kanemaru, an ear, nose and throat physician.

Back in 2011, Kanemaru and his colleagues reported the results of a randomized clinical trial in which 48 study participants with one or more eardrum perforations treated with sponges soaked in a growth factor called b-FGF. The remaining eight participants received sponges immersed in a saline solution. The sponges were glued in place with a fibrous protein sealant and allowed to heal for three weeks before any crust over the eardrum was removed.

Although it sometimes took up to four attempts to get the rupture closed, all but one of the eardrum repairs worked for those treated with the growth-factor-soaked sponges. In contrast, nine of ten perforations treated with a saline-soaked sponge failed to close properly1. None of the participants experienced any serious side-effects.

In that initial study, enrollment was limited to patients with a condition known as a ‘dry’ perforation, which is easier to heal than a perforation which is wet due to the presence of infection-fighting pus.

Since then, Kanemaru has shown that his non-invasive regenerative treatment also works for patients with the active ‘wet’ type of ear inflammation. It just requires repeated cleansing of the middle ear prior to the procedure. His team has also extended the method for people whose ear canals are difficult to see and require the use of a fiber-optic endoscope.

“With these procedures,” Kanemaru says, “we achieved 80 per cent regenerative rates even in previously excluded patients.”

Now, Kanemaru hopes to convince Japanese regulators to approve the procedure for use outside a research setting. He is also adapting the technique for doctors in developing countries who don’t have access to expensive hospital equipment.


  1. Kanemaru, S., Umeda, H., Kitani, Y., Nakamura, T., Hirano, S. & Ito, J. Regenerative treatment for tympanic membrane perforation. Otology & Neurotology 32, 1218–1223 (2011).  | article

About the Researcher

Shin-Ichi Kanemaru, Director, Head & Neck Surgery, Department of Otolaryngology, Kitano Hospital, Osaka, Japan

Named one of the best doctors in Japan since 2010, Shin-Ichi Kanemaru specializes in surgeries of the middle ear, inner ear, temporal bone and skull base, and his research focuses on regenerative treatments for injuries to the ears, vocal cords and airways.

Kitano Hospital

Read this next

Feature | 4 July 2017

Clinical trials on trial

Poor standards in clinical trials waste time and money, and cost lives. Global cooperation is the only way to raise the bar.

Research Highlight | 2 May 2018

Surgery brings on the smooth talk

A Japanese surgical procedure gives patients their voices back

Feature | 7 March 2018

Living well to a hundred and beyond

The public were given a preview of therapies that promise to preserve the quality of life of people well into old age