Perilymphatic fistula in guinea pigs: natural evolution versus surgical treatment.

UNLABELLED: Perilymphatic fistulas still represent a major treatment challenge. In some cases, its surgical closure can reduce auditory and vestibular sequelae.

AIM: To compare the behavior of cochlear window perilymphatic fistulas in guinea pigs as to their natural evolution and immediate surgical closure.

MATERIALS AND METHODS: Experimental study. Forty guinea pigs were submitted to cochlear window membrane lesion and randomly broken down into two groups: open fistula (OF) and surgically closed fistula (SCF). We found the summation potential (SP) and action potential (AP) latencies and amplitudes and the SP/AP ratio at three times: pre-fistula (PRE), immediate post-fistula (IPF) and late post-fistula (LPF).

RESULTS: There was a significant drop in amplitudes and raise in SP and AP latencies among the times studied. As to the SP/AP ratios, there was a reduction between PRE and IPF, both were significant. There was no behavior difference between the OF and SCF.

CONCLUSIONS: Within the time frame considered, guinea pigs submitted to cochlear window membrane lesions evolved with a worsening in potentials and latencies. Despite the partial improvement in electrophysiological parameters, surgical closure did not prove statistically more effective than natural evolution.