Medical devices and methods for removing a predetermined portion of soft tissue from a target tissue layer, thereby creating a channel between two side walls of the target tissue layer, are described. The medical device is a cutting tool comprising: an elongated round body extending along a longitudinal axis and having a uniform outer cross-section at a proximal side thereof; a cutting portion at a distal side of the elongated body, comprising at a distal end thereof a cutting edge of a first cross-section being smaller than said outer cross-section, and a distally and continuously decreasing outer cross-section; and a chamber extending along the longitudinal axis inside the cutting tool from said cutting portion, the chamber having dimensions enabling storing of the removed soft tissue portion inside the chamber thereby providing a validation to the channel creation.