An endoscopic surgical blade having a low-profile design, with an upper cutting surface and a lower cutting surface at its distal end and having a non-cutting radiused surface at the top end of the upper cutting surface, and the upper cutting surface and lower cutting surface meet at a crotch therebetween is disclosed. The blade is part of an endoscopic knife assembly which also contains a hollow knife tube hollow that allows the insertion of an endoscope for viewing of the surgical procedure. The endoscopic knife assembly can be used for in endoscopic surgery by insertion of the assembly through a slotted cannula. A method for a performing an operative procedure on a target tissue in a subject using the endoscopic knife assembly having a low-profile blade with an upper cutting surface and a lower cutting surface is also described.