[Relevance of Simpson's grades in the resection of grade I meningiomas].

Objective: Compare the number of recurrences in patients with WHO Grade I meningiomas that underwent microsurgical resection.

Introduction: In 1957 Simpson established five grades for surgical resection for intracranial meningiomas and recurrence rate. He thought that an aggressive removal of these tumors with dura and bone was necessary to cure them. Development of new diagnostic methods, advances in anatomopathology and microsurgical technique lead us to question if this scale has a value nowadays.

Methods: A retrospective analysis was performed. All patients operated from grade I meningiomas between February 2006 to December 2015 were included. Pre and postoperative MRI as well as histology were analyzed. A multivariate analysis was performed, a < 0.05 was considered statistically significant.

Results: There was no statistical significant difference between patients undergoing Simpson Grade I, II, III or IV resection ( = 0,3117). This could be best stated for Simpson Grade I and II resection, where the number of patients included in the study was higher. When we analyze tumor location there was not significant difference in recurrence between groups ( = 0,2203).

Conclusion: For grade I meningiomas there is no significant difference in the recurrence between patients with a Simpson Grade I or II resection, thus increasing morbidity of the surgery is not justified. A new resection scale should be designed taking into account the WHO classification.