Microsurgery is surgery on very small blood vessels (microvascular) and nerves (microneurosurgery) such as those less than 3 to 5 millimeters in diameter. Microsurgery is done through an operating-room microscope using specialized instruments and tiny needles with ultrafine sutures.

It is used to reattach severed fingers, hands, arms, and another amputated parts to the body by reconnecting the small blood vessels and restoring the circulation before the tissue starts to die.

Microvascular surgery also can be used for reconstruction of defects on the face, trunk, and limbs after cancer resection and other ablative surgeries.