This scale classifies the morphology of aneurysm remnants into five grades:

I - <50% of neck size;

II - >50% of neck size;

III - residual lobe of a multi-lobulated sac;

IV - residual portion of sac <75% of aneurysm size;

V - residual portion of sac >75% of aneurysm size 1).

1)
Sindou M, Acevedo JC, Turjman F. Aneurysmal remnants after microsurgical clipping: classification and results from a prospective angiographic study (in a consecutive series of 305 operated intracranial aneurysms). Acta Neurochir (Wien). 1998;140(11):1153-9. doi: 10.1007/s007010050230. PMID: 9870061.