Electrosurgical instrument

An electrosurgical instrument for applying radiofrequency energy and/or microwave frequency energy to biological tissue, the instrument comprising:

• a distal part comprising an instrument tip for applying radiofrequency energy and/or microwave frequency energy to biological tissue, wherein the instrument tip comprises a first conductive element and a second conductive element;
• a coaxial feed cable comprising an inner conductor, a tubular outer conductor coaxial with the inner conductor, and a dielectric material separating the inner and outer conductors, the coaxial feed cable being for conveying radiofrequency energy and/or microwave frequency energy to the distal part;
• wherein:
• the inner conductor is electrically connected to the first conductive element and the outer conductor is electrically connected to the second conductive element through a rotatable connection between the distal part and the coaxial feed cable that allows rotation of the distal part relative to the coaxial feed cable about a central axis of the distal part;
• the instrument comprises an actuator for rotating the distal part in a first rotational direction relative to the coaxial feed cable;
• the instrument comprises a tubular housing in which the coaxial feed cable is received;
• the distal part is rotatably mounted at a distal end of the tubular housing;
• the instrument comprises a biasing element configured to rotationally bias the distal part in an opposite second rotational direction when the distal part is rotated in the first rotational direction;
• the biasing element is connected to the distal part and to the tubular housing;
• and
• the rotatable connection comprises a flexible transmission line.