ObjectiveTo study the anatomicopathological relation between facial nerve (FN) and acoustic neuronoma (AN) and summarize the techniques of how to protect facial nerves in microsurgery. MethodsA retrospective analysis of 585 patients with acoustic neuronmas treated by microsurgery for the first time between January 2007 and March 2012 was carried out. Anatomicopathological relation between FN and AN and protection of the facial nerve were described. ResultsThe tumors were totally removed microsurgically in 552 patients, and the total removal rate was 94.4%. Subtotal removal was performed in 33 patients. Facial nerve was anatomically preserved in 558 cases, and the rate of facial nerve preservation was 95.4%. After one-year follow-up, 549 patients had House-Brackmann Ⅰ-Ⅳ function. The location and shape of the FN along the tumor was identified as the follows: FN displaced along the ventral and superior surface of the tumor in 279 patients (47.7%), the ventral and central in 243 (41.5%), the ventral and inferior in 33 (5.6%), the dorsal in 10, the superior pole in 6, the inferior pole in 3, and FN surrounded in 11. ConclusionGood understanding of the meaning of anatomicopathological relation between FN and AN, intraoperative monitoring and perfect microneurosurgical skills are important in achieving the goal of total resection of acoustic neuromas and anatomic reservation of the facial nerve.
摘要:目的: 探討磁共振波譜(MRS)對鑒別橋小腦角神經鞘瘤與腦膜瘤的價值。 方法 :對8例神經鞘瘤和8例腦膜瘤病例進行MRI平掃和增強掃描,并采用點分辨波譜序列(PRESS,TR/TE=2000/136ms)進行單體素波譜分析。從事磁共振診斷專業的醫師根據腫瘤的MRI及MRS表現特征進行鑒別診斷。 結果 :盡管多數神經鞘瘤(5/8)和腦膜瘤(6/8)具有典型的MRI表現特征并僅經MRI即可得到正確鑒別,但部分病例(5/16)為不典型表現者,如腦膜瘤呈長T1長T2信號并伴有囊變,以及神經鞘瘤呈等信號、均勻強化且不伴有囊變或內聽道擴大者,鑒別診斷困難。MRS顯示腦膜瘤的膽堿/肌酸比值(Cho/Cr)(2.74±1.47)略高于神經鞘瘤(2.70±1.21),但差異無統計學意義。丙氨酸(Ala)在腦膜瘤中的出現率(4/8)顯著高于神經鞘瘤(0/8)(Plt;0.05),谷氨酸鹽/谷氨酰胺(Glx)在腦膜瘤中的出現率(5/8)也高于神經鞘瘤(2/8);而肌醇(Ins)在神經鞘瘤中的出現率(4/8)高于腦膜瘤(2/8)。結合MRS表現,在MRI上尚難鑒別的病例可被明確診斷,并與最終病理結果相符。 結論 : MRI有助于多數橋小腦角神經鞘瘤與腦膜瘤的鑒別診斷,但對不典型病例有一定局限性;MRS對不典型病例的鑒別具有重要的參考價值。Abstract: Objective: To explore the value of magnetic resonance spectroscopy (MRS) in the differentiation of neurinoma and meningioma in the cerebellopontine angle. Methods : 16 cases, including 8 cases of meningiomas and 8 cases of neurinomas, underwent MRI (plan and gadoliniumenhanced scan) and singlevoxel proton MRS (PRESS series, TR/TE=2000/136ms). MRI and MRS results were reviewed and differential diagnoses were made by professional radiologists. Results : Although most cases (11/16) were typical and clearly classified on MRI, atypical cases were also observed, such as meningioma of long T1/T2 signal intensity with small cystic foci, and neurinoma of isointensity and homogenous enhancement without cystic change or enlargement of internal acoustic meatus. The choline to creatine ratio (Cho/Cr) of meningioma (2.74±1.47) was higher than that of neurinoma (2.70±1.21), however the difference was not significant (Pgt;0.05). Alanine was observed in 4/8 meningiomas but none of neurinomas (Plt;0.05), and glutamine/glutamate was more frequently visualized in meningiomas (5/8) than in neurinomas (2/8), whilemyoinositol was more frequently observed in neurinomas (4/8) than in meningiomas (2/8). With MRS, cases difficult to differentiate were clearly and correctly classified. Conclusion : Although most CPA neurinomas and meningiomas can be diagnosed by MRI, MRS is useful for the differential diagnosis of atypical cases.
ObjectiveTo investigate the procedure and effectiveness of posterior approach for operation of atlantoaxial subdural extramedullary nerve sheath tumors.MethodsBetween January 2012 and March 2017, 9 patients with atlantoaxial subdural extramedullary nerve sheath tumors were treated, including 7 males and 2 females, aged 25-62 years (mean, 45.4 years). There were 8 cases of neurinoma and 1 case of neurofibroma. The tumors were located at C1 in 1 case and C1, 2 in 8 cases. The disease duration ranged from 5 to 120 months, with an average of 45.9 months. The neural function was rated as grade D in 8 cases and grade E in 1 case according to the American Spinal Injury Association (ASIA) grading system. The Japanese Orthopaedic Association (JOA) score was 12.8±2.5. All patients underwent posterior cervical surgery. The laminae were replanted and fixed in 2 cases. The atlantoaxial or occipitocervical axis was not fixed in all patients.ResultsThe operation time was 90-343 minutes, with an average of 179.2 minutes. The intraoperative blood loss was 50-1 000 mL, with an average of 335.6 mL. No relevant complication occurred after operation. All patients were followed up 6-21 months (mean, 11.1 months). The postoperative X-ray films showed the good stability of the cervical spine. All patients had complete tumor resection and no recurrence. The replanted laminae achieved fusion and the internal fixation was firm. According to ASIA grading system, 3 patients of preoperative ASIA grade D had upgraded to grade E at 3 months after operation, while the remaining patients had no change in grading. The JOA score was 15.1±1.4 at 6 months after operation, which was significantly improved when compared with that before operation (t=4.221, P=0.003).ConclusionThe atlantoaxial subdural extramedullary nerve sheath tumor (including the ventral tumor) can be removed completely via posterior approach. The axis lamina can be replanted and fixed with the small titanium plate or lamina screw when necessary, and the atlantoaxial or occipitocervical fixation was not needed.