Patent ID: 7815623

Claim:
A method of delivering one or more materials to the brain of a subject, the method comprising the steps of: a) positioning a stepped cannula in the brain of the subject, wherein the stepped cannula reduces reflux of the one or more materials in the brain of the subject and wherein the stepped cannula comprises: i. two or more co-axially disposed segments, each segment having an exterior diameter that defines the exterior diameter of the cannula, wherein the exterior diameter of the segments is different; and ii. one or more tubular components extending through the lumen of the cannula, wherein at least one tubular component comprises a tubing that reduces loss of material delivered to the brain through the cannula, and further wherein the at least one tubular component extends from 1 mm to 10 mm beyond the distal end of the lumen; b) delivering the one or more materials to the brain through the cannula using a convection enhanced delivery pump, wherein at least one material comprises an adeno-associated virus (AAV) vector.