A vessel dissector used in conjunction with an endoscope is provided with a lumen for receiving the endoscope; a blunt dissecting tip provided on a distal end of an elongated cannula permitting tissue dissection while viewing internal body structures via an objective lens of the endoscope; and a vessel severing tool extending through at least a portion of the elongated cannula and translatable longitudinally relative to the elongated cannula, and the vessel severing tool comprises an electrode-carrying member translatable circumferentially within an arcuate slot extending through an outer surface of the vessel dissector, wherein the arcuate slot comprises an inner radius, an outer radius and a central radius, wherein the outer radius is greater than the inner radius and the central radius is located between the outer radius and the inner radius so the arcuate slot provides a uniform opening through which the electrode-carrying member can extend and retract.