The present invention relates to methods and devices for formation of microconduits in tissue, particularly using an impedance sensing drill to form microconduits. One embodiment of the invention is an impedance sensing drill comprising a drilling assembly, a control module, mechanically connected to the drilling assembly for controlling the depth of drilling by the drilling assembly； and a sensor, electrically connected to the drilling assembly and control module for detecting a change in an electrical impedance of a material being drilled. Another embodiment is a method of forming a microconduit in a material, which comprises the steps of drilling into the material, monitoring an electrical impedance of the material, and stopping the drilling into the material when a change in the impedance is detected, thereby forming microconduit.
