[Local antibiotic administration decreases risk of inner ear damage in effodation]

Mobilising the stapes via the removal of the tympanosclerotic plaques from the oval window niche (effodation) and stapedectomy or malleovestibulopexy are the different procedures generally available for the surgical therapy of stapes fixation due to tympanosclerosis. These techniques bear a significant risk of sensory hearing loss. Here we analyse our results using the mobilisation technique together with locally applied antibiotics.

Nineteen ears in seventeen patients with tympanosclerosis involving the stapes and its footplate which underwent stapes mobilisation between 1991 and 1999 have been investigated retrospectively. According to the literature this operation has a high risk of cochlear hearing loss. To reduce this risk, azlocillin was instilled locally during removal of tympanosclerotic plaques.

Different operation techniques have been used: classic type III with placement of a cartilage disc on the head of the stapes (4), interposition of the incus (3), interposition of the head of malleus (1), interposition of a ceramic-PORP (6) and cartilage columella in cases of significant stapes footplate erosion (3). In two operations the chain was intact and no reconstruction was necessary. Pure-tone-audiometry showed no significant decrease of bone-conduction thresholds. Preoperatively 4 (21.1%) ears had an average air-bone-gap < or = 30 dB, while postoperatively 15 (78.9%) ears had this level of hearing.

Until the exact causes of the loss of hearing after mobilisation or stapedectomy in cases of tympanosclerosis are known, the local administration of antibiotics is certainly recommended, bearing in mind the initial hypothesis that infection may be jointly responsible for cochlear hearing loss on mobilisation or stapedectomy in cases of tympanosclerosis.