An endoscopic instrument (1700, 1800) insertable within a single instrument channel of an endoscope, the endoscopic instrument (1700, 1800) comprising: a power-driven instrument head configured to cut tissue at a site within a subject, the power-driven instrument head having a first distal end and a first proximal end, the first distal end of the power-driven instrument head defining a material entry port (1713, 1813) through which the cut tissue can enter the endoscopic instrument (1700, 1800); a body coupled to the first proximal end of the power-driven instrument head and configured to drive the power-driven instrument head, the body comprising a powered actuator (1705, 1805) and a flexible tubular member (1730, 1846) having a second distal end and a second proximal end, the second proximal end of the flexible tubular member (1730, 1846) defining a material exit port; the powered actuator (1705, 1805) having an actuator distal end and an actuator proximal end, including a drive shaft (1708, 1808) having a distal shaft end (1708a, 1808a) and a proximal shaft end (1708b, 1808b), the distal shaft end (1708a, 1808a) coupled to the first proximal end of the power-driven instrument head and configured to drive the power-driven instrument head to cut the tissue, the drive shaft (1708, 1808) having an inner wall defining a hollow portion; the second distal end of the flexible tubular member (1730, 1846) coupled to the actuator proximal end of the powered actuator (1705, 1805), and the hollow portion of the drive shaft (1708, 1808) of the powered actuator (1705, 1805) fluidly coupling the material entry port (1713, 1813) of the power-driven instrument head and the material exit port of the flexible tubular member (1730, 1846); an aspiration channel (1760, 1860) extending from the material entry port (1713, 1813) of the power-driven instrument head to the material exit port of the flexible tubular member (1730, 1846), the second proximal end of the flexible tubular member (1730, 1846) is configured to couple to a vacuum source such that the cut tissue entering the aspiration channel (1760, 1860) via the material entry port (1713, 1813) is removed from the aspiration channel (1760, 1860) at the material exit port while the endoscopic instrument (1700, 1800) is disposed within an instrument channel of an endoscope. a power-driven instrument head configured to cut tissue at a site within a subject, the power-driven instrument head having a first distal end and a first proximal end, the first distal end of the power-driven instrument head defining a material entry port (1713, 1813) through which the cut tissue can enter the endoscopic instrument (1700, 1800); a body coupled to the first proximal end of the power-driven instrument head and configured to drive the power-driven instrument head, the body comprising a powered actuator (1705, 1805) and a flexible tubular member (1730, 1846) having a second distal end and a second proximal end, the second proximal end of the flexible tubular member (1730, 1846) defining a material exit port; the powered actuator (1705, 1805) having an actuator distal end and an actuator proximal end, including a drive shaft (1708, 1808) having a distal shaft end (1708a, 1808a) and a proximal shaft end (1708b, 1808b), the distal shaft end (1708a, 1808a) coupled to the first proximal end of the power-driven instrument head and configured to drive the power-driven instrument head to cut the tissue, the drive shaft (1708, 1808) having an inner wall defining a hollow portion; the second distal end of the flexible tubular member (1730, 1846) coupled to the actuator proximal end of the powered actuator (1705, 1805), and the hollow portion of the drive shaft (1708, 1808) of the powered actuator (1705, 1805) fluidly coupling the material entry port (1713, 1813) of the power-driven instrument head and the material exit port of the flexible tubular member (1730, 1846); an aspiration channel (1760, 1860) extending from the material entry port (1713, 1813) of the power-driven instrument head to the material exit port of the flexible tubular member (1730, 1846), the second proximal end of the flexible tubular member (1730, 1846) is configured to couple to a vacuum source such that the cut tissue entering the aspiration channel (1760, 1860) via the material entry port (1713, 1813) is removed from the aspiration channel (1760, 1860) at the material exit port while the endoscopic instrument (1700, 1800) is disposed within an instrument channel of an endoscope.