ABSTRACT
<p><b>BACKGROUND</b>Determining the nerve of origin for vestibular schwannoma (VS), as a method for predicting hearing prognosis, has not been systematically considered. The vestibular test can be used to investigate the function of the superior vestibular nerve (SVN) and the inferior vestibular nerve (IVN). This study aimed to preoperatively distinguish the nerve of origin for VS patients using the vestibular test, and determine if this correlated with hearing preservation.</p><p><b>METHODS</b>A total of 106 patients with unilateral VS were enrolled in this study prospectively. Each patient received a caloric test, vestibular-evoked myogenic potential (VEMP) test, and cochlear nerve function test (hearing) before the operation and 1 week, 3, and 6 months, postoperatively. All patients underwent surgical removal of the VS using the suboccipital approach. During the operation, the nerve of tumor origin (SVN or IVN) was identified by the surgeon. Tumor size was measured by preoperative magnetic resonance imaging.</p><p><b>RESULTS</b>The nerve of tumor origin could not be unequivocally identified in 38 patients (38/106, 35.80%). These patients were not subsequently evaluated. In 26 patients (nine females, seventeen males), tumors arose from the SVN and in 42 patients (18 females, 24 males), tumors arose from the IVN. Comparing with the nerve of origins (SVN and IVN) of tumors, the results of the caloric tests and VEMP tests were significantly different in tumors originating from the SVN and the IVN in our study. Hearing was preserved in 16 of 26 patients (61.54%) with SVN-originating tumors, whereas hearing was preserved in only seven of 42 patients (16.67%) with IVN-originating tumors.</p><p><b>CONCLUSIONS</b>Our data suggest that caloric and VEMP tests might help to identify whether VS tumors originate from the SVN or IVN. These tests could also be used to evaluate the residual function of the nerves after surgery. Using this information, we might better predict the preservation of hearing for patients.</p>
Subject(s)
Adult , Female , Humans , Male , Hearing , Neuroma, Acoustic , Pathology , Vestibular Nerve , PhysiologyABSTRACT
<p><b>OBJECTIVE</b>To discuss the advantages and disadvantages of transcallosal-interforniceal approach for resection of the third ventricle and the pineal region tumors.</p><p><b>METHODS</b>The clinical data of 24 cases from July 2008 to March 2011 were retrospectively analyzed. All 24 patients operated by transcallosal-interforniceal approach, among them, there were 14 males and 10 females, with a average age of 32 years ranged from 17 to 65 years and with medical history from 1 month to 10 years. Issues of managements were analyzed and discussed, including reasonable incision design, the managements of draining vein, the site and the length of the incision of the corpus callosum, tumor exposure in increased intracranial pressure, prevention of complications, skills of surgery, treatments of obstructive hydrocephalus, and postoperative managements.</p><p><b>RESULTS</b>In the 24 cases, there were 5 cases of pineal parenchymal tumors, 4 cases of germinoma, 3 cases of astrocytoma, 2 cases of hypothalamus hamartomas, 2 cases of ependymoma, 2 cases of mixed germ cell tumour, 2 cases of malignant lymphomas, 1 case of pineoblastoma, 1 case of dermoid cyst, 1 case of chordoid glioma and 1 case of craniopharyngioma. After surgeries, total removal achieved in 9 cases, and subtotal removal in 10 cases and partial removal in 5 cases. Operative mortality was 0. Combined third ventriculostomy were performed in 13 cases. Postoperative complications occurred in 5 cases, including frontoparietal epidural hematoma in 1 case; postoperative short-term memory loss in 3 cases, postoperative memory loss within 1 month in 2 cases and within 3 months in 1 case; frontoparietal subdural effusion in 1 case and the effusion disappeared without any treatment. Ventriculoperitoneal shunt was performed in 1 case.</p><p><b>CONCLUSIONS</b>The transcallosal-interforniceal approach is ideal for the removal of tumors in third ventricle as well as majority tumor in posterior of third ventricle in a skillful hand. Tumor resection combined with third ventriculostomy is the significant advantages in the approach.</p>