OBJECT: The object of this study was to investigate the impact of surgical treatment on tremor caused by posterior fossa tumors. METHODS: The authors performed a retrospective evaluation of 6 cases involving patients with tremors due to posterior fossa tumors. Patients who had been treated with neuroleptic medication or had a family history of movement disorders were excluded. All patients had postural or kinetic tremors. Tremor was mainly unilateral. The study group included 5 women and 1 man. Mean age at surgery was 59 years. Five patients underwent total or subtotal tumor resection, and 1 patient underwent stereotactic biopsy only. The histological diagnosis was epidermoid tumor in 2 patients, metastasis in 2 others, and vestibular schwannoma and low-grade glioma in 1 each. RESULTS: Two patients had no improvement of tremor, postoperatively. In both of these patients the tumor (low-grade glioma in 1, metastasis in the other) involved the dentate nucleus directly. In the other patients, a compressive effect on the dentate nucleus or the dentatothalamic pathways was present without invasion of the cerebellar structures, and immediate or gradual amelioration of the tremor was observed postoperatively. CONCLUSIONS: The prognosis of tremor due to posterior fossa tumors appears to depend mainly on the involvement of tremor-generating structures. The prognosis appears to be favorable in those patients with compression of these substrates, whereas primary invasion by tumor has a poor prognosis. Caution must be used in generalizing the findings of this study because of the small number of cases in the series.
OBJECT: The object of this study was to investigate the impact of surgical treatment on tremor caused by posterior fossa tumors. METHODS: The authors performed a retrospective evaluation of 6 cases involving patients with tremors due to posterior fossa tumors. Patients who had been treated with neuroleptic medication or had a family history of movement disorders were excluded. All patients had postural or kinetic tremors. Tremor was mainly unilateral. The study group included 5 women and 1 man. Mean age at surgery was 59 years. Five patients underwent total or subtotal tumor resection, and 1 patient underwent stereotactic biopsy only. The histological diagnosis was epidermoid tumor in 2 patients, metastasis in 2 others, and vestibular schwannoma and low-grade glioma in 1 each. RESULTS: Two patients had no improvement of tremor, postoperatively. In both of these patients the tumor (low-grade glioma in 1, metastasis in the other) involved the dentate nucleus directly. In the other patients, a compressive effect on the dentate nucleus or the dentatothalamic pathways was present without invasion of the cerebellar structures, and immediate or gradual amelioration of the tremor was observed postoperatively. CONCLUSIONS: The prognosis of tremor due to posterior fossa tumors appears to depend mainly on the involvement of tremor-generating structures. The prognosis appears to be favorable in those patients with compression of these substrates, whereas primary invasion by tumor has a poor prognosis. Caution must be used in generalizing the findings of this study because of the small number of cases in the series.