For the first time, surgeons performing cochlear implants have access to a navigation tool that provides live insights during electrode insertion and final placement. Benefits include confirming that the electrode is in the correct final position immediately upon insertion, preventing the wait for imaging post insertion to confirm correct placement.
Cochlear’s Nucleus SmartNav System has only been on the Australian market since June 2023, yet it is already in use in nearly half the hospitals that perform cochlear implants.
Leading cochlear implant surgeons Professor Robert Briggs and Dr Benjamin Wei from Melbourne, featured below, are among surgeons providing excellent early feedback on the intraoperative tool that gives real time information during surgery for in-theatre decision-making around angular depth and speed of electrode insertion.
The system includes an iPad app, which visually gives a representation of what happens as the electrode is inserted, and a surgical processor. It provides diagnostic measurements to confirm integrity which Cochlear says can improve surgical consistency, facilitate optimised electrode positioning and increase surgical confidence. It also means electrode irregularities can be detected and corrected during surgery.
Mr Nicholas Guildhary, a Cochlear audiologist rolling out the SmartNav across Asia-Pacific, says its controlled market release data on 119 surgeries in North America and Europe reveals 97% of surgeons using the system say it reduces complexity in surgery and has a positive impact on their surgical process.
“There are pre-operative tools that help surgeons plan cochlear implant surgery but this is the first tool to show what’s happening in surgery and give a live diagnostic,” Guildhary says. “It’s unique, having that real-time diagnostic for Cochlear Nucleus implants, which comprise most of our implants.”
Cochlear says traditionally surgeons rely on surgical skill and a steady hand to insert the electrode array but SmartNav provides unblinded insight during insertion. If an issue is identified, they can address it immediately.
The implant directly stimulates the cochlear nerve so signals are sent to the brain and interpreted as sound but sub-optimal electrode placement can affect this. With final electrode placement correlating with hearing outcomes, it’s important to have reassurance and confirmation the electrode is placed properly and performing as intended, Cochlear says.
The technology enables the surgeon to see if the electrode is performing and test how the nerve is responding to the electrode during insertion.
Generally, surgeons confirm electrode placement via X-ray imaging in the operating room or post-surgery but this is based on imaging availability and some hospitals may not have immediate access. The system also gives surgeons the ability to compare how steady their insertion is over time.
Cochlear says wireless connectivity and intuitive design deliver a seamless workflow through the iPad. The surgeon views details including:
- Placement check which gives information on final electrode placement and is designed to reduce the need for intraoperative imaging post electrode insertion.
- Speed of insertion which provides feedback on speed and consistency of electrode insertion.
- Impedance which provides assurance the device is operating as intended before leaving theatre.
- Advanced and AutoNRT measurements for obtaining neural response telemetry thresholds, providing flexibility in settings for optimal measurement.
- Electrical Stapedius Re ex Threshold (eSRT) to confirm nerve response to electrical stimulation to establish stimulation thresholds.
Audiologist mapping benefit
Another benefit is that intraoperative data is securely imported into Custom Sound Pro fitting software at the recipient’s fitting clinic to inform audiologist mapping of the sound processor, contributing to efficient post-operative management. Currently data is sent to audiologists in paper versions.
“Compared to the current state, there’s no way to easily send data from the theatre to the clinic where the recipient will have their sound processor switched on. Through secure cloud or email transfer, data collected during surgery through SmartNav can be seamlessly transferred with the click of a button to the fitting clinic and used to do the initial activation with the sound processor,” Guildhary says. “Anything that better informs the audiologist of what’s happened in surgery helps because it might influence how they program the implant.”
Several studies including multicentre studies of about 500 cases have compared SmartNav surgeries with standard surgeries with results expected to be published soon.
The system also won gold in 2022 in the Australian Good Design Awards’ medical and scientific product category.
Highly recommended by surgeons
One of Australia’s most experienced cochlear implant surgeons, Professor Robert Briggs, says it’s a convenient and effective way of checking that the electrode is working and the ‘placement check’ feature confirms the electrode is in the correct final position.
Prof Briggs has been doing cochlear implant surgery for more than 30 years and has performed more than 1,000 procedures.
The University of Melbourne Clinical Professor operates at The Royal Victorian Eye and Ear Hospital and the Royal Children’s Hospital, as well as St Vincent’s Private Hospital. He has been using the SmartNav routinely during surgery at The Eye and Ear and St Vincent’s over the past six to 12 months.
“It’s a new system to assist with intraoperative and early post-operative testing of the implant,” he explains. “I knew it was being developed by Cochlear and we were keen to be involved in using it and testing it out.
“It allows testing of the implant function and helps position the electrode inside the inner ear. It measures responses from the nerve at the time of the operation and is a convenient, effective and easy method of checking that the electrode is working, that the nerve is responding as we expect and it tells us that the electrode is in the right position.”
Surgeons could not previously tell if an electrode might fold on itself, creating a problem inside the inner ear, Prof Briggs adds.
“We used to rely solely on an X-ray after insertion to check this but SmartNav has given an additional measurement of helping confirm (if an electrode is folding). There have been cases where the placement check shows the electrode has possibly got a fold in the top of it which means it can be removed, replaced immediately and checked again to ensure it has not folded and is in the correct place. This is a major advantage.
“If the electrode doesn’t go in as far as it should, it won’t give the same degree of electrical stimulation benefit. A fold is relatively uncommon but it’s very important to recognise if it does happen because it can then be corrected immediately. It’s better to recognise at the time of insertion rather than post-operatively with X-ray because if not recognised initially it needs a separate operation to fix it.”
Prof Briggs says imaging is still done at the same time or immediately after the insertion or post-surgery as a double check to ensure the electrode is in the expected position. He says the system’s speed of insertion feature may “help with hearing preservation”, in future.
“It’s better for the surgeon and the patient,” Prof Briggs adds. “It’s an elegant system and I’m sure Cochlear will continue to refine it and develop more things in terms of telling where the electrode is inside the ear which will become more helpful. We recommend all surgeons in Victoria use it; this is already happening in our clinics and I know they’re keen to continue. Undoubtedly it will be increasingly widely used around Australia as it’s a worthwhile system.”
Improves surgery efficiency and assesses implant integrity
Also praising the system is ENT surgeon Dr Benjamin Wei who also operates at St Vincent’s Private Hospital and The Eye and Ear in Melbourne. He has been performing cochlear implantation for 14 years and has used it in more than 30 cochlear implant surgeries since 2023. Dr Wei says he is impressed with how it improves the efficiency of surgery.
“The real time feedback of the insertion process including speed, depth and angle provides extra information to help surgeons achieve a better placement of the electrode and also provides reassurance that the electrode is functioning satisfactorily,” he says. “In terms of technology it’s one of the biggest advances in the assessment of the implant integrity as it confirms the correct placement of the implant. It has really changed the management and is more user friendly and efficient. I highly recommend SmartNav. It’s one of the extra tools that can provide surgeons additional information which makes the surgery more efficient.”
Dr Wei says it also reduces theatre time which is important for children and elderly patients under general anaesthesia and is helpful in multiple cases, due to reducing the time required to perform integrity testing of the implant during surgery. However, imaging is still routinely performed at the same time or immediately after the insertion or a post-surgery CT scan double checks and confirms the electrode is in the expected position.
“Sometimes the nurse tells us the iPad reading but I also use the voice activation setting so I can hear how deep it is in the cochlea without having to look at the iPad,” he says. In future, this information could also prove valuable for research particularly around the speed of insertion and placement in terms of trauma, he adds.