[Relevance of Simpson's grading system for resections in WHO grade I meningiomas]. / Relevancia de la escala de Simpson en la resección de meningiomas de grado I de la OMS.

ABSTRACT

OBJECT The aim of this study is to assess if the recurrence rates and recurrence/progression-free survivals (RFS) are different after Simpson's grades I, II, III and IV resections in World Health Organization (WHO) grade I meningiomas. MATERIAL AND METHODS: A retrospective review was conducted on the data of patients who underwent surgical treatment of WHO grade I meningiomas located in convexity, falx/parasagittal, and skull base (anterior/media/posterior) between June 1991 and December 2011. In Simpson's grade IV resections, surgical treatment was supplemented with radiotherapy/radiosurgery on the tumour remains. A comparison was made on the recurrence rates and RFSs between Simpson's grades I, II, III, and IV resections, both overall and in tumour subsets according to their location. RESULTS: A total of 208 meningiomas were included in this study. There were no significant differences in recurrence rates and RFSs between Simpson's grades I, II, III, and IV. No significant differences were noted between the different degrees of Simpson in any of the location groups. In convexity meningiomas, the recurrence rates were 7% and 33% in Simpson's grades I and III resections, respectively (P=.131). CONCLUSIONS: It has been shown that the rates of tumour control in meningiomas are not related to Simpson grades. In falx/parasagittal and skull base meningiomas, more aggressive attempts of tumour resection must be balanced against the risks of damaging critical neurovascular structures. In convexity meningiomas, a Simpson's grade I resection should be attempted first.