A surgical tool comprising: a main unit including: an inner tube having a first end and a second end, the inner tube including a cutting surface at the first end and a flexible portion located between the first end and the second end; and an outer tube having a first end and a second end, the outer tube including a cutting window at the first end and a flexible portion located between the first end and the second end, the inner tube received within the outer tube so as to align the cutting surface of the inner tube with the cutting window of the outer tube ; a rigid sheath having a first end and a second end, the rigid sheath removably receives the main unit such that the cutting window extends beyond an opening of the first end of the rigid sheath ; and a connector including: a first connector portion located on the outer tube located closer to the second end of the outer tube than the flexible portion such that the flexible portion of the outer tube is located between the first connector portion and the first end of the outer tube ; and a second connector portion located on the rigid sheath adjacent to the second end of the rigid sheath , the first connector portion when connected to the second connector portion detachably couples the rigid sheath to the outer tube , wherein the main unit can be completely removed from the rigid sheath when the first and second connector portions are uncoupled from each other. a main unit including: an inner tube having a first end and a second end, the inner tube including a cutting surface at the first end and a flexible portion located between the first end and the second end; and an outer tube having a first end and a second end, the outer tube including a cutting window at the first end and a flexible portion located between the first end and the second end, the inner tube received within the outer tube so as to align the cutting surface of the inner tube with the cutting window of the outer tube ; an inner tube having a first end and a second end, the inner tube including a cutting surface at the first end and a flexible portion located between the first end and the second end; and an outer tube having a first end and a second end, the outer tube including a cutting window at the first end and a flexible portion located between the first end and the second end, the inner tube received within the outer tube so as to align the cutting surface of the inner tube with the cutting window of the outer tube ; a rigid sheath having a first end and a second end, the rigid sheath removably receives the main unit such that the cutting window extends beyond an opening of the first end of the rigid sheath ; and a connector including: a first connector portion located on the outer tube located closer to the second end of the outer tube than the flexible portion such that the flexible portion of the outer tube is located between the first connector portion and the first end of the outer tube ; and a second connector portion located on the rigid sheath adjacent to the second end of the rigid sheath , the first connector portion when connected to the second connector portion detachably couples the rigid sheath to the outer tube , a first connector portion located on the outer tube located closer to the second end of the outer tube than the flexible portion such that the flexible portion of the outer tube is located between the first connector portion and the first end of the outer tube ; and a second connector portion located on the rigid sheath adjacent to the second end of the rigid sheath , the first connector portion when connected to the second connector portion detachably couples the rigid sheath to the outer tube , wherein the main unit can be completely removed from the rigid sheath when the first and second connector portions are uncoupled from each other. <EOS>