An international call for a new grading system for cerebral and cerebellar cavernomas

Surgical indications for cerebral cavernous malformations remain significantly center- and surgeon-dependent. Available grading systems are potentially limited, as they do not include epileptological and radiological data. A novel grading system is proposed for supratentorial and cerebellar cavernomas: it considers neuroradiological features (bleeding, increase in size), neurological status (focal deficits and seizures), location of the lesion and age of the patient. The score ranges from -1 to 10; furthermore, surgery should be considered when a score of 4 or higher is present. Based on neuroradiological characteristics, 0 points are assigned if the CCM is stable in size at different neuroradiological controls, 1 point if there is an increase in volume during follow-up, 2 points if intra- or extra-lesional bleeding <1 cm is present and 3 points if the CCM produced a hematoma >1 cm. Regarding focal neurological deficits, 0 points are assigned if absent and 2 points if present. For seizures, 0 points are assigned if absent, 1 point if present, but controlled by medications, and 2 points if drug resistant. We considered the site of the CCM, and in case of deep-seated lesions in a critical area (basal ganglia, thalamus) 1 point (-1) is subtracted, while for subcortical or deep cerebellar lesions 0 points are assigned, for CCMs in a cortical critical area 1 point is assigned and in case of lesions in cortical not in critical area or superficial cerebellar area, 2 points are assigned. As far as age is concerned, 0 points are assigned for patients older than 50 years and 1 point for patients younger than 50. In conclusion, a novel grading for surgical decision making in cerebral cavernomas, based on the experience of selected neurosurgeons, basic scientists, and patients, is suggested with the aim of further improving and standardizing the treatment of CCMs. The aim of this paper was also to call for both retrospective and prospective multicenter studies with the aim of testing the efficacy of the grading system in different centers.