Perilymphatic fistula in guinea pigs: natural evolution versus surgical treatment.
Perilymphatic fistulas still represent a major treatment challenge. In some cases, its surgical closure can reduce auditory and vestibular sequelae.


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


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.
Onishi
Ektor Tsuneo
ET
Federal University of São Paulo - Escola Paulista de Medicina.
Fukuda
Yotaka
Y
D000818:Animals; D001300:Audiometry, Evoked Response; D005402:Fistula / Q000601:surgery*; D006168:Guinea Pigs; D007759:Labyrinth Diseases / Q000601:surgery*; D008297:Male; D010498:Perilymph; D011930:Reaction Time; D012075:Remission, Spontaneous; D012405:Round Window, Ear / Q000293:injuries* / Q000601:surgery