In A First, Researchers Confirm Safe Surgical Access To Human Cochlea, Study Says It Will Help Treat Deafness

This feat is important because it will help treat deafness and improve hearing loss in the long-term. The cochlea is the hearing portion of the ear and participates in auditory transduction.

The snail-like region seen in the image is the cochlea, one of the two main parts of the inner ear

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An international team of surgeons and scientists has confirmed the first secure surgical access to the central core of the human cochlea, one of the two main parts of the inner ear. This feat is important because it will help treat deafness and improve hearing loss in the long-term. The research, published November 8 in the journal Scientific Reports, is an important step in the first in-human trials of new cell, gene and drug therapies for the inner ear. 

What is cochlea?

The cochlea is the hearing portion of the ear and participates in auditory transduction, which refers to the process by which the inner ear converts sound waves into electrical impulses and sends them to the brain so that the person can interpret the signals as sound. The human cochlea is shaped like a snail shell. 

In a statement released by Uppsala Universitet in Sweden, one of the universities involved in the study, Helge Rask-Anderson, an author on the paper, said using the advanced 3D imaging techniques, the researchers found new intriguing trajectory pathways for cell delivery.

Why has the discovery of hearing loss treatments been slow?

The human cochlea, which lies in the base of the skull, is encased by the hardest bone in the human body, as a result of which the progress of discovering new treatments for hearing loss has been hampered. Surgeons have used a detailed representation of the microanatomy of the peripheral auditory neural structure to reach the human cochlea safely with a routine surgical approach. 

How is the new research useful?

The team includes researchers from Uppsala University, Guy's and St. Thomas' NHS Foundation Trust in London, University of Sheffield, University of Nottingham, and Western University in Canada. The researchers have proven and confirmed a secure clinical pathway to the inner ear. This will enable the application of a range of regenerative therapies to restore hearing.

Marcelo Rivolta, one of the authors on the paper, said until now, the human cochlea had been inaccessible. Pioneering advanced therapies to repair the auditory nerve, which have already proved successful in animal models, have been hampered by limited anatomical knowledge and the lack of a safe access to Rosenthal's canal. This is the compartment that houses the auditory neurons within the central core of the cochlea. 

Rivolta added that these findings will have an immediate impact on scientists' understanding of the microstructure of the inner ear. 

Dr Simon Chandler, another author on the paper, said the research now paves the way for the successful delivery of regenerative cell therapy for hearing loss. This will bring significant positive impact to healthcare systems and economies across the globe. 

Professor Dan Jiang from Guy's and St Thomas said the research provides intuitive knowledge to ear surgeons about the targets of the future cell, gene and drug therapies, and will allow them to reach those targets safely, as they have been trained to do.

Gerry O'Donoghue, an author on the paper, said the inaccessibility of the human cochlea has hampered the progress of curative treatments for sensorineural hearing loss to date. These findings are important because they will enable the safe delivery of regenerative therapeutics to their target structures within the relatively impenetrable human cochlea. This will de-risk future clinical interventions and pave the way for clinical trials. 

The researchers modelled data from 10 temporal bones to define a safe trajectory for therapeutic access while preserving the cochlea's internal structure.