Petrous bone cholesteatoma. Clinical findings.

Petrous bone cholesteatoma extending beyond the labyrinth involves the petrous pyramid and internal auditory canal. The treatment of the petrous bone cholesteatoma is difficult because of the hearing preservation and its anatomical characteristics. In this paper, we described the clinical findings of two cases treated in our hospital in order to elucidate the surgical strategies for treatment of petrous bone cholesteatoma.<BR>Case 1 was a 66-year-old male with 6 years' history of dizziness. An attic type cholesteatoma was observed in his right middle ear. CT examination revealed that the cholesteatoma extended from the antrum inferiorly, the superior semicircular canal to the upper part of the internal auditory canal. The cholesteatoma was removed completely by translabyrinthine approach with supuralabyrynthine route.<BR>After cholesteatoma matrix was removed from the canal foramen, liquorrhea was observed. His left hearing level was decreased more than 30 dB postoperatively.<BR>Case 2 was a 55-year-old male with 7 years' history of left facial paralysis and left deafness. For the last two years his gait has become ataxic. His left eardrum was adhered completely to the promontory. All middle ear ossicles were sclerotic.<BR>CT and MRI revealed that there was a massive destructive petrous bone cholesteatoma. The lesion was removed by the tranmastoid-translabyrinthine approach. In deeper part of the sino-dural angle, the middle fossa dura was locally so atrophic that the arachnoid membrane was exposed. The cavity was obliterated with the temporal muscle.<BR>In general, lateral skull base approach to the petrous apex can be classified into two procedures, passing through the otic capsule and conserving the otic capsule.<BR>Approach through the otic capsule are including the translabyrynthine and the transcochlear approach. On the other hand, approaches conserving the otic capsule (extra labyrinthine) which are consisted of the middle fossa approach passing above the otic capsule and the retrosigmoid-retrolabyrinthine approach passing behind it are most popular. Decision making of surgical strategy depends on not only the localization and the extension of cholesteatoma, but the remaining function of labyrinth. It can also be necessary that postoperative follow-up study with CT and MRI should be regularly performed in addition to the surgery.