[Evaluation of the postoperative regrowth of the acoustic neurinomas].

Although recent advances in microsurgical removal of acoustic neurinomas has made it possible to preserve, morphologically, the cochlear nerve as well as the facial nerve, functional impairment of the facial nerve is often encountered following total removal of the tumor. In order to avoid such functional morbidity, a surgical procedure can be proposed in which the tumoral capsule attached to a functional structure such as the facial nerve is intentionally left. Along with this surgical procedure and postoperative course observation, postoperative regrowth of the tumor should be precisely evaluated. A few recent reports about this problem have been published since CT scan and MRI have become available. The authors reviewed 66 cases in which postoperative evaluation by high resolution CT scan of the acoustic neurinomas has been carried out in their department more than one year after surgery. Multiple factors such as age at onset, sex, preoperative period, tumor size, vascularity, extent of the tumor removal, residual site, and pathological findings on HE stain were studied in relation to the tumor regrowth. Four cases showed regrowth of the tumor, and one of these tumors was reoperated on. The percentage of regrowth was 7.5% among the tumors which were not totally removed. No significant risk factors for tumor regrowth were noticed in these cases, but tumor regrowth tended to be found in younger patients. The residual tumors which showed regrowth were always located in the internal auditory meatus. In this study, it is apparent that, percentagewise, tumor regrowth is not so prevalent.(ABSTRACT TRUNCATED AT 250 WORDS)