We say that the perforation in mucosal COM becomes permanent when the edge of the perforation gets covered by the epithelial layer, which prevents the healing.
Hence we freshen the margins during tympanoplasty. But is it always so ? Do we always have to freshen the edges ?
Good morning,
1 - the perforation is never permanent "per se" - we usually admit that it is unlikely to resolve spontaneously when it hasn't done so after about six months and so we call them "permanent".
2 - I've seen twice an apparent "permanent" perforation resolve after an acute OM - both in young children with long standing perfs. So it's not a universal fact.
3 - epithelization starts immediately after any injury, much as anywhere else in the skin, and is complete in days. However, the scaring forces in the basement membrane lead the edges to contract, and this in turn will tend to diminish the perimeter and eventually the diameter of the perf, until it reaches complete closure, or else arrives at an equilibrium and leaves a "permanent" perf (you can see this scar tissue when doing a tympanoplasty after freshening the edges - it's like a thick ring). This process evolves under an intact epithelium. So it's not because the epithelization is complete that you stop healing a perforation.
4 - And finally, if you diagnose a perf as permanent and you indicate surgery, you should freshen its edges to restart the healing process I've described above. And putting fascia (or other materials) under-, over- or in-lay helps to guide the scarring and close the perf.
I never refreshen when I remove tympanosclerotic plaques, but that actually has the same effect as refreshening.
As for mucosalisation: clinically I find it difficult to acknowledge what is granular myringitis and what is mucosa on the outer layer. I have the impression that freshening is less important, but it is only an impression...
Sorry for the delayed answer. Mucosalization is epithelization by mucosa. Starts immediately as much as on the skin layer.
Thank you sir.. does the perforation heal when we do an underlay tympanoplasty without freshening the margins of the perforation but raise the tympanomeatal flap 360 degrees except at 12 o'clock. ?
No. For a perforation to heal there must be active healing process, and so you have to trigger it by freshening the edges (unless it is a very recent perforation).
Epithelization is the healing process which may occu in the skin or outer layer of the drum but when it involves the mucus membrane in such case it is called mucosalization, that is healing of the inner layer of the drum. It starts immediatly after the injury and its time is dependent on the size of the perforation.
A chronic perforation resembels fistula where epithelium runs between outer and inner layer of the drum. So to start healing process again, freshening the edge may be of value to remove the fisuluos epithelium
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