US Patent 9114228 Dilator apparatus

A cystotomy apparatus includes a sound from which an advancement device having a cutting tip creates a surgical pathway from the bladder through abdominal tissue to the external abdomen along a predetermined path. The cutting tip is captured and removed from the advancement device in a capture cup located in the predetermined path by an alignment structure. The cutting tip is removed from the advancement device while within the capture cup, to allow a dilator, cannula or catheter to be drawn through the surgical pathway into the bladder.