An energy delivering probe (12) is used for thermally coagulating and/or constricting hollow anatomical structures (HAS) including, but not limited to, blood vessels such as perforator veins. The probe (12) includes a shaft (16) and one, or two, or more electrodes (24, 26) where at least one of the electrodes has a perimeter that increases as it extends proximally. In an embodiment, the shaft comprises a sharp distal tip configured to puncture body tissue and the sharp tip is preferably integrally formed with the distal electrode.