A surgical instrument includes first and second cutting blades, each including a tubular body having proximal and distal ends, with a cutting window disposed at a side of each cutting blade near its distal end. The second cutting blade rotates within the first cutting blade to cut tissue while a vacuum is applied through an internal bore of the second cutting blade. The distal end of each of the cutting blades includes a suction aperture. An area of the first cutting blade suction aperture is smaller than an area of the second cutting blade suction aperture. The instrument is used as a suction tool by applying the vacuum through the internal bore of the second cutting blade while the second cutting blade is stopped from rotating with the cutting windows of the first and second cutting blades misaligned with each other to apply the vacuum through the suction apertures.