Absence of movement disorders after surgical resection of glioma invading the right striatum

Object. Despite the high frequency of striatal lesions, the rate of movement disorders reported in the literature is lower than expected (< 10%). To maximize the extent of resection in low-grade gliomas invading the right striatum, the authors performed a striatal resection in a series of 14 patients, observed the lack of movement disorders following these procedures, and discuss herein the mechanisms likely to explain these findings. Methods. Fourteen patients harboring a low-grade glioma that was infiltrating the right nondominant striatum, and in whom the results of neurological examination were normal, underwent surgery in which intraoperative electrical mapping was used, allowing the identification of pyramidal pathways. The striatum was resected in all procedures, and corticospinal tracts were systematically detected and preserved. Ten patients presented with a transient postoperative motor deficit, and nine with a loss of interest and affect. These symptoms all resolved within 3 months, except for one case of persistent hemiparesis. No postoperative movement disorder was noted, even transitorily. All resections were categorized as either total or subtotal on control magnetic resonance images. Conclusions. These findings show that the nondominant striatum can be removed in cases of glioma invasion without inducing even transitory movement disorders. This phenomenon could be explained by the combined resection of the two classes of striatal neurons, an associated pallidal and thalamocortical resection, or a compensatory recruitment of parallel networks. Thus, these results may allow the surgeon to maximize the extent of removal of low-grade gliomas involving basal ganglia. Striatal resection may induce transient hemiparesis and "athymhormic syndrome," however, necessitating that the patient be clearly informed before surgery.