The instrument. The mesodissection instrument is essentially a modified tissue milling machine comprised of a joystick-driven X-Y slide stage (A), a digital microscope (B) looking up through the slide adjustable from 5X to 60X total magnification, and a mill head (C) on a vertical axis mounted above the slide which lowers a spinning blade onto the slide surface to dissect the tissue. The blade is part of the disposable xScisor (D, described in detail in Figure 3), which simultaneously dispenses and aspirates fluid in a stage speed dependent rate in order to collect the tissue fragments. The user controls tissue dissection via a joystick while viewing the image from the digital microscope on a computer screen. Dissection can be guided using a digital outline that moves on the screen as the stage moves (See Figure 4). After the dissection is complete, the fragments are ejected into a small tube using the plunger control rod (E).