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Nucleus Ltd Cochlear division of Nucleus Ltd Refining the mechanics of the implant Clinical trials overseas Cochlear Ltd today Engineering considerations Manufacture of the implant

To allow the implant to be improved and made accessible to more people it was necessary for it to become a commercial enterprise. Commercialisation of the cochlear implant was essential if it was to be an economically viable project. However the Australian market was too small.

Nucleus Ltd
Nucleus Ltd, a group of companies that manufactured highly developed medical equipment, won a tender to "carry out a market survey and cost development plan for the cochlear implant". (Epstein, 1989: 51)

The four member team responsible for the plan worked on two tasks:

• research overseas to study market potential
• a review of the cochlear implant system design — resulting in a simplified version featuring a single integrated circuit.

In 1981, with the University of Melbourne and the Australian government, Nucleus set out to develop a commercially viable cochlear implant and to carry out a worldwide clinical trial.

Reports were written for both tasks and presented to the Australian government. Nucleus Ltd was awarded the contract to develop the cochlear implant.

Cochlear division of Nucleus
Paul Trainor, Chief Executive Officer, Nucleus Ltd, formed the Cochlear Division of Nucleus he then selected a three member Tiger Team.

A Tiger Team, according to Trainor's philosophy, was a small single-minded group moving forward very quickly on a specific project and as far as possible not distracted by the usual day-to-day commitments of a job. They were relieved of much of the bureaucracy and administration so that they could concentrate on the main task, and they were given fully equal or rotating responsibility for accelerating the work. Naturally, as the project matured so did the necessity for red tape and administrative practice, but at the beginning freedom for the job itself was all important. So the small team began and at first constructed the device by hand, acting as designers and manufacturers and checking each other's work for quality control. (Epstein, 1989: 53)

The team increased in size and each member was responsible for a component. The implant was broken down into:

• implant system design
• integrated circuit design
• promontory simulator: a test which demonstrated whether the nerves of the inner ear were working properly.
• speech processor: received, processed and stored information in a way appropriate to each individual implantee.
• external electric components
• automatic gain control device: necessary to expand or compress incoming sounds to an acceptable level.
• electrode array
• implantable stimulator. (adapted from Epstein, 1989: 53)

Refining the mechanics of the implant
A newly emigrated Polish mechanical engineer, Janusz Kuzma, was responsible for the mechanical aspects of the implant. He

…had to devise a way of sealing (the implant) hermetically with biocompatible material as well as incorporating a mini antenna coil to pick up the signals. He solved the latter problem by looping the coil outside the small round device and enclosing the whole in soft silastic. A new electrode system with 22 electrodes had to be accommodated, and he was also responsible for the design of the external headset. He knew the electronic parts would not function correctly unless the mechanical parts were perfect. He knew the team was dependent on and accountable to public funds. He knew there was a time limit and time was running out. He had many sleepless nights. … (Epstein, 1989: 54)

Building on the University of Melbourne research, Cochlear developed the more advanced 22 channel implant and the wearable speech processor (WSP). The design philosophy was to make a flexible cochlear implant with sophisticated sound processing in the externally worn speech processor. This allowed the recipient to take advantage of improvements in technology without surgically replacing their implanted device.

Twelve months after the team began it had managed to completely redesign the whole cochlear implant system and develop an implantable device. The system was ready for clinical trials.

Clinical trials overseas
Clinical trials of the Australian cochlear implant were set up in Australia and overseas. Competition in electronic engineering and microchip technology in medical devices was world wide and the Australian government wanted to capture some of the overseas market.

For the Cochlear implant to be available to the American market, and indeed world wide the US Food and Drug Administration had to give its official approval. This was achieved in 1985.

Cochlear Ltd today
Since 1988, Nucleus, including Cochlear, had been a wholly owned subsidiary of Pacific Dunlop. In 1995, Cochlear was sold by Pacific Dunlop and floated on the Australian Stock Exchange, as a publicly listed company.

The Nucleus® 24 Contour implant won the Australian Design Award™ of the Year in March 2000. It has some important features:

• an electrode that is curved before insertion into the cochlea
• it places the electrodes closer to the important parts of the cochlea
• does not exert any force on the bone or tissue after it is inserted.

Engineering considerations
Some significant engineering considerations were addressed in the development of the Nucleus® 24:

Simulation of contour insertion (New York University)

Manufacture of the cochlear implant Production of the speech processor The behind-the-ear (BTE) speech processor differs from a conventional body-worn speech processor, as it contains a directional microphone, contained within the same case as the speech processor unit. The production processes for each processor are very similar.

Precision assembly of the cochlear implant (Cochlear Pty Ltd)

Production of the cochlear implant The Cochlear implant itself is made up of three main functional components: 1. the stimulator 2. the antenna coil and 3. the electrode unit. The heart of the stimulator is the Cochlear implant chip, an integrated circuit. The stimulator also contains a ceramic disk, or feedthrough, with twenty-four platinum pins to which each of the twenty-two electrode wires, and two coil wires, are attached in the final assembly. The stimulator is responsible for picking up the signals from the antenna, and sending out the appropriate electrical energy to the electrodes. The stimulator is encased in titanium shells, which are laser welded together. The antenna coil, which forms the loop of the implant, is welded to the stimulator, to form a functional antenna. It is then wound into the shape that you see in the final implant. An extracochlear electrode is assembled, using fine platinum wire, and is also attached to the stimulator. Stimulator components are prepared and cleaned prior to entering the clean room. All antenna coil assembly is conducted in the cleanroom.

Most of the assembly operations for the behind-the-ear speech processor and the stimulator assembly are done under a microscope. In the stimulator production and external production areas, controls are in place to protect the statically sensitive devices being handled, therefore operators wear special lab coats, wrist and heel straps for grounding, and gloves. (Cochlear Pty Ltd)

The cleanroom is a totally controlled environment with set temperature and humidity levels, where electrode assembly and final implant assembly takes place. Strict controls are required during the final assembly of implants to ensure that the final product is clean, and after sterilisation, ready for implantation. Full body garments are worn in the cleanroom, from boots, overalls, hood, mask and gloves.

The electrode unit can either be made up of a straight electrode array or a contoured array.

This is a basic overview of the manufacturing processes involved in producing the components necessary for a functional Cochlear implant system, which transmits signals from outside the body, to the electrode inside the cochlea, allowing the recipient of the implant to hear. Text provided by Cochlear Pty Ltd.

Design process
The following two diagrams illustrate the design process flow. They incorporate the philosophy of plan, do, check, act used by Cochlear Pty Ltd.

Process flow (Cochlear Pty Ltd)

Design process flowchart indicating the stages involved in developing a product. Note the tollgates or check points throughout the process. (Cochlear Pty Ltd) Click image to view enlarged version.

Tollgates
At significant points in the design process Cochlear has set up tollgates or check points where approval from a management team is required before the process can continue. Refer to the design process flowchart when considering the information in the table.