An occlusive device can include a segment including an open end and a proximal end. The occlusive device can include a push wire that is positioned proximal of the proximal end. The occlusive device can include a detachment feature that is attached to the push wire via a detachment groove. The occlusive device can include a sleeve surrounding the push wire. In a non-deployed configuration, the sleeve can surround the detachment feature and prevent release of the proximal end of the segment from the push wire. In a deployed configuration, the proximal end can be flush with a proximal end of the spherical cavity.