Stapedotomy

The Piston with Vein Interposition Technique.

A 0.8 mm. hole is drilled in the footplate, covered with a vein graft, and a 0.4 mm T. P. is used.

The vein forms the stapedio-vestibular interface. The moving surface is 0.8mm in diameter, which is very good for sound transmission.

Advantages :

- You get an immediate seal.

- Adhesions from the lenticular process to the promontory are prevented as the promontory is covered with intima.

- You cannot use an overlong piston, as the vein will get invaginated into the oval window and the appearance will warn you.

- The moving surface is 0.8 mm, so you get better hearing than with a 0.4 mm piston.

- In case of sudden movement due to a loud sound or barotrauma, you will not get a dead ear, as the 0.4 mm piston will not hit the saccule or the utricle (Fig.1A and 1B).

In any operation, the emphasis is on :
1. an accurately made 0.8 mm hole. If there is excessive footplate removal, even if a vein or perichondrium interposition is used, late bulging of the blue membrane, which is directly proportional to the extent of footplate removal, will inevitably give late S.N. loss due to a fistula.

2. A perfect measurement of the length of the piston; if the piston is too short, late conductive hearing loss will result as the hole made in the footplate will re-close. If the piston is too long, permanent sensori-neural (nerve) hearing loss will result, irrespective of whether a vein or soft tissue has been put around the piston.

Clinical application:

We use this technique as far as possible as we feel that there is a greater margin of safety due to the vein.

The stapes prosthesis allows sound vibrations to again pass from the eardrum to the inner ear fluids. The hearing improvement obtained is usually immediate & permanent.

next>