Leakage-resistant tissue treatment apparatus and methods of using such tissue treatment apparatus

An apparatus for treating tissue located beneath a skin surface with high frequency energy, the apparatus comprising:

• a handpiece;
• a treatment tip configured to be removably coupled with the handpiece, the treatment tip including an electrode configured to deliver the high frequency energy to a region of the tissue and a flow passageway;
• a first conduit inside the handpiece, the first conduit including a tubular sidewall and a lumen bounded by the tubular sidewall, the lumen of the first conduit configured to transfer a heat transfer fluid from the handpiece to the flow passageway in the treatment tip when the treatment tip is coupled with the handpiece;
• and
• a flow control valve inside the handpiece, the flow control valve coupled with the first conduit, the flow control valve having a closed position in which the lumen of the first conduit is occluded for reducing leakage of the heat transfer fluid from the handpiece and an open position in which the heat transfer fluid flows through the lumen of the first conduit, and the flow control valve configured to be moved from the closed position to the open position by contact from the treatment tip when the treatment tip is coupled with the handpiece and to move from the open position to the closed position when the treatment tip is removed from the handpiece.