Neurosurgical devices including or used with cannulas or catheters and associated systems and methods are disclosed herein. The neurosurgical devices can include, for example, a cannula having a main portion and an angle-forming member proximate a distal end of the main portion. The angle-forming member can be configured to transition from a substantially straight configuration while the cannula is advanced through tissue along a substantially straight first portion of a path to an angled configuration when the angle-forming member reaches an end of the substantially straight first portion of the path. The neurosurgical devices also can include, for example, a neurosurgical catheter including a surface disrupter, an elongated macerator, or a lateral opening. Neurosurgical catheterization portals also are disclosed. The neurosurgical catheterization portals can, for example, have an adjustable portal that is movable relative to a body to accommodate different entry angles of a catheterization path.