Stapedectomy surgery for a conductive or mixed hearing loss due to otosclerosis usually has wonderful results. The hearing threshold is improved and the quality of sound is very natural. However it does carry risk of a dead ear, which occurs in 0.5-1.0% of surgeries despite the surgery being carried out competently. In

this situation it would leave only one hearing ear on the opposite side. In such a situation it would be strongly advisable not to undergo surgery on the opposite side because of the small risk of a second dead ear. Fortunately there are several options for rehabilitating hearing in this situation with hearing aids of various kinds. A bone anchored hearing aid (BAHA) is one such device which can help. It is placed under the skin in the mastoid bone behind the ear and works by bypassing the middle ear and stimulating the cochlea directly through the bone of the skull. BAHAs have predictable hearing outcomes in conductive hearing losses. This hearing result can be experienced by a trial simulation of the BAHA before undergoing surgery to implant the device. The surgery to implant a BAHA is simple and carries no risk to the underlying hearing. An external speech processor held on by a magnet or small clip generates sound vibration to be transmitted to the implant under the skin.

There are several other kinds of middle ear devices which can also be used in this situation. A device which has recently become available in Australia is the Bonebridge. This is an active middle ear implant which has the source producing the sound vibrations implanted within the mastoid bone behind the ear, rather than externally in the speech processor as with the BAHA. Many other implantable devices which can help are also being investigated. Some are active devices that attach to the middle ear bones such as the Vibrant sound bridge. However these devices require more complex surgery than the Bone Bridge or BAHA for placement. They also required manipulation of the middle ear bones, and hence carry a risk to the underlying hearing. These devices would not be suitable for surgery on the side of an only hearing ear. 

Otosclerosis is a hereditary disease which results in progressive stiffness of the stapes bone, the third of the three middle ear bones. As the stapes bone becomes progressively stiff it transmits sound energy less efficiently through the middle ear resulting in conductive hearing loss. What is so exciting about otosclerosis is that the middle ear component of the hearing loss is treatable by surgery generally called stapedectomy. The principle of this operation is to restore sound transmission to the inner ear bypassing the fixed stapes bone. This can be achieved either by removing the entire stapes bone (stapedectomy) or drilling a very fine hole through it (stapedotomy) and replacing it with an artificial stapes bone. When stapes operations were first developed in the 1950s, it was necessary to remove the whole stapes bone before introducing an artificial stapes replacement (generally made of fine stainless steel wire and fat taken from the ear lobe).

As the micro drills, and more recently lasers, were developed it became possible to drill a fine hole (less than 1 mm in diameter) through the stapes footplate and introduce a replacement stapes bone (made of titanium/ platinum and Teflon) to effectively bypass the fixed bone, leaving the remaining footplate largely intact. Both operations in skilled hands produced wonderful hearing results, and both operations still carry similar risks of permanent and severe hearing loss (dead ear, less than 0.5%). However, the stapedotomy operation produces less trauma to the inner ear, preserving the higher hearing frequencies. The modern stapedotomy replacement bones are also safer to revise if necessary and the replacement prosthesis is compatible with MRI (magnetic resonance imaging) scanners if imaging of the region is required later on. Because of these advantages, all modern stapes surgery for otosclerotic hearing loss is in the form of stapedotomy. 

The mobile phone with the inbuilt telecoil is the Oricom EZY100. It also has a +25dB volume boost. I’ve had some implant patients who love the phone and others who haven’t had the best result, so it would be good if they could trial the system before purchasing or have assurance by Oricom that they can return it if not happy. Alternatively, your clinic could become a distributor in which case it would be worth having a demonstration phone on hand that clients can trial before they purchase from you. I’ve found the whole range of Oricom phones very useful but on the odd occasion some people haven’t had much success with them and so the ability to return it or have a trial before purchase is really useful.

Cochlear implant surgery is best and most safely performed under a combination of general anaesthetic with assistance from local anaesthesia injected into the skin behind the ear to make the recovery after the surgery almost painless. The surgery involves drilling hard bone in the skull to enter the cochlea, while negotiating several sensitive structures including the facial nerve and nerve of taste. The ear drum, lining of the brain as well as the carotid artery and jugular vein are only a few millimetres away. The opening into the cochlea (cochleostomy) is around 1 millimetre in diameter (less than a dressmaker’s pin head) and the cochlear implant electrode around 0.6mm in diameter (like a bristle on your toothbrush). The surgery is performed under a microscope which magnifies these structures many times to make them clearly visible to the operating surgeons and generally takes around an hour and a half to perform. As you can imagine, trying to lie perfectly still for that period of time while the surgery is being performed is uncomfortable. The slightest movement (not to mention more vigorous movements such as deep breathing, a cough, sneeze or even swallowing) appears like a mini earthquake under the microscope. The sensation of the drilling would also be unpleasant, and lastly when the electrode is finally inserted into the cochlea extreme dizziness (vertigo) might occur. For all these reasons it best that implant surgery is performed while the patient is pleasantly asleep. We are fortunate today to have excellent new general anaesthetic agents which are safe, act quickly and have very few side effects which were commonly a problem with the older agents. All patients are carefully evaluated before surgery and any health factors which might interfere with the anaesthetic or surgery can be identified and corrected, if possible, or controlled beforehand. I have performed ear and mastoid surgery in hundreds of patients including over 200 CI surgeries, many of them elderly patients (the oldest 92!) – rarely has their fitness for a general anaesthetic been a reason to prevent the surgery for occurring. 


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