Intramedullary low grade astrocytoma and ependymoma. Surgical results and predicting factors for clinical outcome

Abstract

The optimal time point for surgery of intramedullary spinal astrocytomas and ependymomas is often debated on, as predicting factors are poorly defined. The current single-institutional study was conducted to retrospectively analyze prognostic factors for postoperative functional outcome in these patients. All consecutive adult patients with intramedullary astrocytomas or ependymomas (except filum terminale ependymomas) were included. Imaging data, McCormick score (MCS), and detailed neurological evaluation were stringently applied preoperatively, 1 week, and 6 months postoperatively for functional evaluation of all patients. End points were early and late functional outcome. Prognostic factors were obtained from univariate and multivariate logistic regression analysis. Forty-four patients were included (29 ependymomas World Health Organization (WHO) grades I or II, 8 astrocytomas WHO grade I, and 7 astrocytomas WHO grade II). Overall perioperative morbidity was 34%, and there was no mortality. Complete tumor resection was achieved in 79% of ependymomas, 50% of astrocytomas WHO grade I, and 14% of astrocytomas WHO grade II (significantly more often in ependymomas than in astrocytomas, p < 0.05). Early and late functional outcome were highly intercorrelated (p < 0.01), but not correlated to histology. Preoperative MCS <3 and extent of tumor <5 levels were significantly (p = 0.01 and p < 0.05) associated with a favorable outcome (MCS <3) in early and late follow-up. An MCS of less than 3 and a tumor extent of less than 5 levels are the most important factors for a favorable postoperative functional outcome. Therefore, surgery should be initiated before significant clinical symptomatology or substantial tumor growth occurs.