Dr Anders Tjellström, the founding father of Baha treatment, opened a new pathway to better hearing by developing the full potential of bone conduction. Here Dr Tjellström recalls how it all began — almost by accident — when he was a student doctor under Professor Per-Ingvar Brånemark, the man who pioneered the use of titanium dental implants for good bonding in bone:
“In the late-60s, I was working as a resident at the ENT department in Sahlgrenska University Hospital in Gothenburg and had the opportunity to assist Professor Brånemark in some of his surgery. Fortunately, I was soon accepted as one of his Ph.D. students.
It was important for Professor Brånemark to be able to measure precisely the osseointegration – the fusion between the titanium implant and the bone. Complete osseointegration was essential to give the implant good stability, and is still a pre-requisite for our Baha solution today.
One time when we used acoustic stimulus to measure osseointegration our patient suddenly said they could clearly hear the sound through their skull! It was one of the first observations of hearing through direct bone conduction.
I spoke to some patients who used external bone conductors to help them hear better. These devices were held in place with a steel spring and the patients complained about discomfort due to pressure on their head, poor hearing performance and last but not least, the stigma associated with such devices. I thought to myself, ‘Maybe osseointegration can also work with an implant that penetrates the skin’. A vibrator attached to an implant in the bone behind the ear might solve the problems for these patients.
I invited three patients with chronic ear disease to take part in a study. I had been their ENT surgeon for several years, and we knew each other very well. They had drainage problems in the external ear canal and weren’t able to use conventional hearing aids with a mould.
We placed a titanium implant in the bone behind the ear. After healing and osseointegration, a vibrator was attached to the implant. The responses were very exciting. “I can hear birds for the first time since my childhood” was one of the comments I remember. These results were encouraging, even though the ‘sound processor’ we were using at that time was very primitive.
We established a close cooperation with Professor Bo Håkansson at Chalmers University of Technology, and in the mid-70s we built the very first prototypes of the Baha sound processor. While the same basic principles are still used today, modern Baha processors with the latest technology look completely different from the old days.
Nobel Biocare, and later Entific Medical, became the industrial partners in bone conduction hearing solutions. In 2005, Cochlear BAS was created and took over the production and marketing of the Baha brand. There was a greater focus on technical development and Cochlear spent – and still spends – a significant amount of resource on R&D. As a result, technology has come a long way and today’s Baha device is a refined, high-tech sound processor with the capacity to adapt to different noise environments. Something we had never imagined possible all those years ago.
The design of the implant is a good example of on-going development. It is now a little wider and has a new surface to improve osseointegration. The development of a special DermaLock coating for the abutment is another example of ongoing innovation. The DermaLock layer promotes good contact and reduces the risk of skin reactions. The surgical procedure has also been refined, with a shorter incision and no soft tissue reduction. Easier and faster surgery helps both the patient and surgeon.
Then there’s the new Baha Attract system, which enables bone conduction hearing without any skin penetration at all. A magnetic disc is attached under the skin to the Baha implant. The external processor, which is also magnetically attached, transfers the sound through the intact skin to the skull, stimulating the cochlea of the inner ear. Being able offer the Baha without any skin penetration at all is certainly another great step forward.
I’m sure there are many more development to come, and it is gratifying to know that my colleagues and I have been able to play a small part in giving so many people a fuller life.”
~ Dr Anders Tjellström
Do you have a question for Dr Tjellström? Let us know in the comments section!