Impact of surgical treatment on tremor due to posterior fossa tumors

Abstract

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.