A surgical instrument, comprising: an outer member defining a cutting window; a cutting member at least partially positioned within the outer member, the cutting member including a sharp edge for cutting tissue protruding through the cutting window; and a drive member coupled to the cutting member such that in response to only a rotational force applied to the drive member in a single rotational direction, the cutting member (i) rotates and (ii) moves linearly in a back-and-forth motion, the drive member having a continuous helical groove including a first helical channel and a second helical channel, the first helical channel and the second helical channel being blended at their respective ends to form the continuous helical groove, at least a portion of the first helical channel having a first helical angle that causes the cutting member to move linearly in a first direction at a first linear speed and at least a portion of the second helical channel having a second helical angle that is smaller than the first helical angle that causes the cutting member to move linearly in a second opposing direction at a second linear speed that is slower than the first linear speed when the drive member is rotated at a constant speed, wherein the surgical instrument is configured to perform a cutting operation when the cutting member moves linearly in the first direction at the first linear speed and wherein the surgical instrument is configured to perform an aspirating operation when the cutting member moves linearly in the second direction at the second linear speed, and wherein when the cutting member moves linearly in the first direction, the cutting member moves across the cutting window to close the cutting window and to cut tissue in the cutting window, and when the cutting member moves linearly in the second direction, the cutting member withdraws to open the cutting window. an outer member defining a cutting window; a cutting member at least partially positioned within the outer member, the cutting member including a sharp edge for cutting tissue protruding through the cutting window; and a drive member coupled to the cutting member such that in response to only a rotational force applied to the drive member in a single rotational direction, the cutting member (i) rotates and (ii) moves linearly in a back-and-forth motion, the drive member having a continuous helical groove including a first helical channel and a second helical channel, the first helical channel and the second helical channel being blended at their respective ends to form the continuous helical groove, at least a portion of the first helical channel having a first helical angle that causes the cutting member to move linearly in a first direction at a first linear speed and at least a portion of the second helical channel having a second helical angle that is smaller than the first helical angle that causes the cutting member to move linearly in a second opposing direction at a second linear speed that is slower than the first linear speed when the drive member is rotated at a constant speed, wherein the surgical instrument is configured to perform a cutting operation when the cutting member moves linearly in the first direction at the first linear speed and wherein the surgical instrument is configured to perform an aspirating operation when the cutting member moves linearly in the second direction at the second linear speed, and wherein when the cutting member moves linearly in the first direction, the cutting member moves across the cutting window to close the cutting window and to cut tissue in the cutting window, and when the cutting member moves linearly in the second direction, the cutting member withdraws to open the cutting window.