ELECTROSURGICAL INSTRUMENT WITH NON-LIQUID THERMAL TRANSFER

Various embodiments provide an electrosurgical instrument comprising: a flexible coaxial transmission line arranged to convey microwave energy; a radiating tip portion connected at a distal end of the flexible coaxial transmission line and configured to receive the microwave energy, the radiating tip portion comprising: a distal coaxial transmission line for conveying the microwave energy; and a needle tip mounted at a distal end of the distal coaxial transmission line, the needle tip being arranged to deliver the microwave energy into biological tissue; and a heat sink mounted at an interface between the flexible coaxial transmission line and radiating tip portion. The heat sink is in thermal communication with a proximal end of the distal coaxial transmission line and configured to draw thermal energy from the radiating tip portion. Also, a maximum outer diameter of the radiating tip portion is smaller than an outer diameter of the flexible coaxial transmission line. An associated electrosurgical system is also disclosed.