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

Abstract

Introduction: 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.

Material and methods: 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.

Results: 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.

Conclusion: 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.