T1 - Ossicular chain reconstruction
A CT scan is a form of X-Ray imaging which allows us to see the body in much clearer detail than plain X-Rays. The CT scan splits the image into thin layers, sliced like a salami, so that we can see much greater detail and pinpoint what is happening at any given point. It is only in recent years that scanners have been able to produce slices thin enough to give us useful information on the state of the middle ear. Some ear surgeons always require a CT scan before operating. In the days before CT scans, some ear surgeons always wanted mastoid X-rays before operating. I have never found them all that useful. Even with the best scanners, we don’t get anywhere near as good a view as we get with the operating microscope during surgery – full colour, three dimensional and up to 40 times magnification. It is impossible to tell with a scan whether some part of the ossicular chain is fixed – this can only be determined by trying to move it during surgery. Many of the patients referred to me for ear surgery have already had scans. They rarely make any difference to what I plan on doing. I do not need a scan as a matter of routine. A CT scan is needed if we suspect complications, especially if we suspect there may be spread of disease into the brain.
"Alternatives in Biocompatable Ossicular Implants." vol.
porous polyethylene partial ossicular replacement prosthesis ..
Other options include the insertion of a strut made out of an artificial bone, called hydroxy apatite. This artificial bone is porous and allows for the ingrowth of blood vessels and the complete assimilation of the artificial bone into the individual’s middle ear. With the modern day use of hydroxy apatite, there has been a marked reduction in the rejection of ossicular reconstruction prostheses.
A variety of prostheses may be used in ossicular reconstruction ..
Reconstruction of this type of ossicular discontinuity can be performed at the time of tympanoplasty surgery. There are several options. If the gap is small, it can be bridged by inserting a small piece of bone or cartilage taken from the patient at another site (behind the ear or from the lobe of tissue called the tragus in front of the ear). If there is a larger gap, then the incus bone is removed and modelled into a tooth-like prosthesis, using the operating microscope. This is then reinserted between the stapes and the malleus in order to reestablish continuity of the ossicular chain.