gms | German Medical Science

The aim of this study was to evaluate the clinical impact of intraoperative MRI on resection of low grade gliomas.

The charts from patients, who underwent craniotomy and extirpation of a low grade glioma (WHO grade I and II) from August 1997 until November 2002, were retrospectively reviewed. Operations were performed inside a vertically open configured 0.5 T MR scanner "Signa SP/i". Depending on the intraoperative MR morphological extent of resection patients were assigned to either the "gross total resection" (GTR) or the "subtotal resection" (STR) group.

Thirty-one patients were included in the study, 18 men and 13 women. The mean age was 37.0±12.4 years. Histologically, 2 astrocytomas WHO grade I (6.5%), 22 astrocytomas WHO grade II (70.9%), 4 oligoastrocytomas WHO grade II (12.9%), and 3 oligodendrogliomas WHO grade II (9.7%) were found. In 2 patients transient neurological deficits occurred perioperatively, 3 patients suffered from persistent deficits (total morbidity 9.7%). The median postoperative follow-up time was 41.4 months. The 75^th percentile of the postoperative time to clinical progression was 55.0 months for the GTR group and 29.1 months for the STR group (univariate analysis, p=0.154). In 15 patients (48.4%) tumour recurrences were observed. The 75^th percentile of the postoperative time to MR morphological progression was 38.5 months for the GTR group and 16.1 months for the STR group (univariate analysis, p=0.236). In 7 cases a re-operation was necessary. Secondary malignant tumour progression occurred in 2 patients of the GTR group and in 3 patients of the STR group. During follow-up period 2 patients (6.5%) died due to tumour progression. The 2-years-survival rate was 96.3% and the 5-years-survival rate was 92.3%.

Although not statistically significant, a remarkable difference between the GTR and the STR group regarding the postoperative time to clinical progression and to MR morphological tumour progression could be found. This is in line with the data in the literature. The perioperative morbidity rate of 9.7% rate is higher than the reported morbidity rates in the literature but may be due to a high number of patients with tumours close to eloquent brain areas. The median follow-up period of 3.45 years (41.4 months) was too short for evaluation of the postoperative survival time. Referring to the literature, the estimated length of survival is nearly 10 years.