A surgical instrument comprises a hollow tube (18) having a cutting window (16) at the distal end portion. An inner tube (15) is disposed within the tube (18) and is mounted for rotation about its longitudinal axis. A cutting tool (17) is located at the distal end of the tube (15), and is positioned adjacent to the cutting window (16). An outer tube (14) is provided over the tube (18). A motor (5) is provided for rotating the inner tube (15), and saline is fed to the cutting window (16) via a passageway (25) between the tubes (15) and (18). The inner tube (15) has a central lumen (24) through which tissue cut by the cutting tool (17) is removed under the action of a source of suction (12). The outer surface of the tube (18) is covered with an electrically insulating layer (22) and coagulating RF signals are supplied between the tube (18) and the outer tube (14) so as to coagulate tissue at the cutting window (16). A weakened portion (43) of the outer tube (14) ensures that when the outer tube (14) and hollow tube (18) are bent to form a curved portion (42), the relative positioning of the respective distal ends of the tubes (14) and (18) is maintained.Linvention concerne un instrument chirurgical qui comporte un tube creux (18) muni dune fenêtre de coupe (16) au niveau de la portion dextrémité distale. Un tube intérieur (15) est disposé à lintérieur du tube (18) et est monté tournant sur son axe longitudinal. Un outil de coupe (17) est situé au niveau de lextrémité distale du tube (15), et est positionné à côté de la fenêtre de coupe (16). Un tube extérieur (14) recouvre le tube (18). Selon linvention, un moteur (5) fait tourner le tube intérieur (15), et une solution saline est alimentée vers la fenêtre de coupe (16) par lintermédiaire dun passage (25) entre les tubes (15) et (18). Le tube intérieur (15) a une lumière centrale (24) à travers laquelle le tissu découpé par loutil de coupe (17) est enlevé sous laction dune source daspiration (12). La surface extérieur
