Tympanosclerosis

Over the years surgeons all over the world have had poor hearing results with tympanosclerosis and even world famous authorities who performed direct t.p. at a second stage had upto 10% S-NHL so they advocate closure of the perforation and recommend a hearing aid. Ossicular fixation by tympanosclerosis in large central perforations is common.

Why is it so difficult?

Tympanosclerosis is sub-mucosal so peeling off the plaques leaves raw areas and bare bone.

The 2 opposing raw areas will unite by fibrous or bony ankylosis so mobilization, however meticulously done, will be followed by refixation. In cases of triple ossicle fixation, manipulation of the stapes is fraught with danger if the stapediovestibular joint is violated at the time of initial surgery. Therefore such cases must always be done in 2 stages.

Any violation of the stapedio-vestibular joint will result in SNHL.

So if the stapes is fixed, a 2-stage operation is required.

How to warn the patient?

The gelfoam patch test is useful to predict to the patient the possibility of a 2-stage operation if the AC fails to improve when the perforation is closed by a moist piece of gelfoam.

In the bilateral case, it also helps to select the side to be done first. We do the side with the better patch test.

Using a mini-endaural incision, an extended cortical mastoidectomy is performed and Tympanosclerosis is cleared from the mastoid, attic and aditus.

Special care is taken to remove the tympanosclerosis deep & anterior to the malleus head & deep to the incus & the fossa incudis.

To facilitate removal of tympanosclerosis deep to the HOM and incus, or if there is a risk of excessive mobilization of the ossicular chain during removal of tympanosclerosis, the incus is removed and placed in saline.

All raw areas are lined with silastic.

If the stapes is mobile, the M/I are bypassed and a 2-cartilage technique is performed. Not a M-S assembly.

If the stapes is fixed,

The incus is disarticulated and the malleus head rotated out of the attic on the axis of the tensor tympani and tympanosclerosis is cleaned deep to it.

If the incus is normal, it is removed and replaced in its normal anatomic position on a bed of Silastic and gelfoam.

If the incus is necrotic, it is removed and reshaped in such a way that the short process resembles the long process and a notch is drilled to articulate with the head of the malleus. This is then articulated with the malleus and the stapes on a bed of Silastic and gelfoam.

The perforation is closed by interlay.

The fixed Stapes is always tackled at a second stage.

Post-op., tympanometry is done to check adequate ventilation.

After 6 months the second stage endomeatal tympanotomy is performed and the superstructure removed with a laser.

There is a high incidence of SN loss with direct piston techniques as reported by various authors.

Therefore a direc piston technique is NEVER used in Tympanosclerosis cases.

A discrete 0.8 mm. Hole is made and a 0.4 mm. Dia. Piston placed with vein interposition, the Causse Technique.

If however it is not possible to create a discrete hole or if the neo-incus does not permit perfect anchor to the piston, a total platinectomy is performed. With a total platinectomy a piston is never used even with vein interposition, as late bulging of the endosteum will cause a perilymph fistula. So, cartilage with vein interposition is used wherein a precisely measured Y-shaped tragal cartilage is cut using the piston measuring jig.

In all cases intra-operative audiometry is performed with a sterile apparatus.

Pure malleus head fixation is dealt with by a small atticotomy & the entire HOM & incus are lined with silastic. The incudo-stapedial joint is disarticulated to prevent damage to the inner ear & then

re-articulated at the end of the procedure. The attic defect is reconstructed be cartilage.