Wunderlich G, Knorr U, Herzog H, Kiwit J C, Freund H J, Seitz R J
Department of Neurology, Heinrich-Heine-Universität Düsseldorf, Germany.
Neurosurgery. 1998 Jan;42(1):18-26; discussion 26-7. doi: 10.1097/00006123-199801000-00005.
Low-grade brain tumors may remain asymptomatic in contrast to malignant gliomas. The mechanisms underlying the preservation of cerebral function in such gliomas are not well understood.
We used positron emission tomography and transcranial magnetic stimulation for presurgical monitoring of motor hand function in six patients with gliomas of the precentral gyrus. All patients were able to perform finger movements of the contralesional hand.
Movement-related increases of the regional cerebral blood flow occurred only outside the tumor in surrounding brain tissue. Compared with the contralateral side, these activations were shifted by 20 +/- 13 mm (standard deviation) within the dorsoventral dimension of the precentral gyrus. This shift of cortical hand representation could not be explained by the deformation of the central sulcus as determined from the spatially aligned magnetic resonance images but was closely related to the location of the maximal tumor growth. Dorsal tumor growth resulted in ventral displacement of motor hand representation, leaving the motor cortical output system unaffected, whereas ventral tumor growth leading to dorsal displacement of motor hand representation compromised the motor cortical output, as evident from transcranial magnetic stimulation. In two patients, additional activation of the supplementary motor area was present.
Our data provide evidence for the reorganization of the human motor cortex to allow for preserved hand function in Grade II astrocytomas.
与恶性胶质瘤相比，低级别脑肿瘤可能无症状。此类胶质瘤中脑功能得以保留的潜在机制尚不清楚。
我们使用正电子发射断层扫描和经颅磁刺激对6例中央前回胶质瘤患者术前的手部运动功能进行监测。所有患者对侧手均能进行手指运动。
与运动相关的局部脑血流增加仅发生在肿瘤周围的脑组织而非肿瘤内部。与对侧相比，这些激活在中央前回的背腹维度内偏移了20±13毫米（标准差）。这种皮质手部代表区的偏移无法用根据空间对齐的磁共振图像确定的中央沟变形来解释，而是与肿瘤最大生长部位密切相关。肿瘤向背侧生长导致手部运动代表区向腹侧移位，运动皮质输出系统未受影响，而肿瘤向腹侧生长导致手部运动代表区向背侧移位则损害了运动皮质输出，这从经颅磁刺激中可以明显看出。在2例患者中，还出现了辅助运动区的额外激活。
我们的数据为人类运动皮质的重组提供了证据，以允许二级星形细胞瘤患者保留手部功能。
