ObjectiveTo analyse the microsurgical treatment and facial nerve preservation of giant acoustic neuromas. MethodsUnder the conditions of facial nerve monitoring, 400 patients with giant acoustic neuromas underwent microsurgical removal via suboccipital retrosigmoid approach between January 2005 and January 2013. There were 186 males and 214 females, with the age ranged from 15 to 74 years (mean, 41.6 years). The disease duration was 2-13 years (mean, 2.4 years). The lesions were located at the left cerebellopontine angle region (CPA) in 191 cases, right CPA in 200 cases, bilateral CPA in 9 cases. The clinical manifestations included unilateral hearing loss and tinnitus as first symptoms in 389 cases, facial numbness in 373 cases, unilateral facial paralysis in 370 cases, headache in 269 cases, lower cranial nerve symptoms with drinking cough and dysphagia in 317 cases, and unstable gait in 342 cases. Preoperative skull base thin layer CT showed varying degrees of horn-like expansion in ipsilateral internal auditory canal opening. MRI showed cysts in 78 cases and solid masses in 322 cases; with hydrocephalus in 269 cases. Postoperative cranial MRI or CT was taken to observe the extent of tumor resection. The preservation of facial nerves in anatomy was assessed by intraoperative microscope video and electrophysiological monitoring; the facial nerves function was assessed according to House-Brackmann (HB) classification on the first day after operation; and the rehabilitation of facial nerve function was also assessed at discharge and at 1 year postoperatively by using HB grade. ResultsTotal tumor removal was achieved in 372 cases (93.00%), and subtotal removal in 28 cases (7.00%). One case died of delayed brainstem ischemia at 14 days after operation, and 1 case died of lung infection at 20 days after operation; 398 cases were followed up 6 months to 8 years (mean, 3.5 years). Recurrence occurred in 1 case because of neurofibromatosis at 5 years after operation. The rate of anatomical preservation of the facial nerve during operation was 91.75% (367/400), and the functional preservation rate at the first day after operation was 62.75% (251/400). The HB grade of facial nerve function showed significant difference aomng 3 time points (at the first day, at discharge and at 1 year after operation) (χ2=23.432, P=0.000). Complications included postoperative intracranial infection in 11 cases (2.75%), cerebrospinal fluid leakage in 29 cases (7.25%), aggravated lower cranial nerve symptoms in 18 cases (4.50%), subcutaneous effusion in 13 cases (3.25%), second operation to remove hematoma in 9 cases (2.25%), postoperative circumoral herpes simplex virus infection in 25 cases (6.25%), and all complications were cured after symptomatic treatment. Postoperative hydrocephalus disappeared in 261 cases. ConclusionSurgical operation is the first choice in the treatment of giant acoustic neuromas. Under the auxiliary of neural electrophysiological monitoring, the microsurgery operation via suboccipital retrosigmoid approach for giant acoustic neuromas has extremely low mortality and high preservation rate of facial nerve function.
Objective To study the MRI features of intracranial solitary fibrous tumor (ISFT). Methods MRI features of 8 patients with ISFT treated between December 2010 and December 2015 were retrospectively analyzed and relavent literatures about its neuroimaging were reviewed. Results All the 8 cases were single solitary fibrous tumor (SFT), among which 4 arose from and beneath the tentorium, 2 in the left cerebellopontine angle, 1 in jugular foramen region and 1 in saddle area. All tumors had clear boundary, 3 were oval or round, 2 were irregular-shaped, 2 were lobulated and 1 was dumb-bell shaped. Tumor size ranged from 35 to 65 mm. On pre-contrast MRI, 5 cases were mixed with hypo to hyperintense signals on (T1 weighted image) T1WI and heterogeneous on (T2 weighted image) T2WI. The rest 3 cases were featured by solid and cystic components; the solid component was hypo to isotense on T1WI and hypointense on T2WI while the cystic areas, which were not enhanced in the postcontrast images, were hypo and hyperintense on T1WI and T2WI, respectively. All the areas with low T2 signal intensity were strongly enhanced after gadolinium administration. Flow-empty actions, peritumoral edema and “dural tail” sign was found in 6, 3 and 0 cases, respectively. All the 3 cystic cases were confirmed as malignant ISFT while the rest 5 were benign. Conclusions MRI manifestation of ISFT has some characteristics. There may exist some correlations between the intratumoral cyst and malignant potential. However, the diagnosis of ISFT remains dependent on histopathology.