A motor driven surgical system comprising: a handle assembly; a motor configured to drive the surgical system; and an interchangeable surgical tool assembly, operatively coupled to the handle assembly, comprising: a nozzle assembly; a proximal closure tube having a proximal end operatively coupled to a distal end of the nozzle assembly; an articulation connector having a proximal end operatively coupled to a distal end of the proximal closure tube; a surgical end effector comprising a first jaw and a second jaw and having a proximal end operatively coupled to a distal end of the articulation connector; a flexible shaft circuit strip disposed within at least a portion of the proximal closure tube, at least a portion of the articulation connector, and at least a portion of the surgical end effector; a knife member slideably disposed within the surgical end effector; and a knife bar operatively connected to a proximal end of the knife member, wherein the knife bar comprises a first laminated plate disposed on a first side of the flexible shaft circuit strip and a second laminated plate disposed on a second side of the flexible shaft circuit strip, and wherein the knife bar is configured to reciprocate along a longitudinal axis of the proximal closure tube; and characterised in that the first laminated plate is configured to reciprocate along the first side of the flexible shaft circuit strip and the second laminated plate is configured to reciprocate along the second side of the flexible shaft circuit strip. a handle assembly; a motor configured to drive the surgical system; and an interchangeable surgical tool assembly, operatively coupled to the handle assembly, comprising: a nozzle assembly; a proximal closure tube having a proximal end operatively coupled to a distal end of the nozzle assembly; an articulation connector having a proximal end operatively coupled to a distal end of the proximal closure tube; a surgical end effector comprising a first jaw and a second jaw and having a proximal end operatively coupled to a distal end of the articulation connector; a flexible shaft circuit strip disposed within at least a portion of the proximal closure tube, at least a portion of the articulation connector, and at least a portion of the surgical end effector; a knife member slideably disposed within the surgical end effector; and a knife bar operatively connected to a proximal end of the knife member, wherein the knife bar comprises a first laminated plate disposed on a first side of the flexible shaft circuit strip and a second laminated plate disposed on a second side of the flexible shaft circuit strip, and wherein the knife bar is configured to reciprocate along a longitudinal axis of the proximal closure tube; and characterised in that the first laminated plate is configured to reciprocate along the first side of the flexible shaft circuit strip and the second laminated plate is configured to reciprocate along the second side of the flexible shaft circuit strip. a nozzle assembly; a proximal closure tube having a proximal end operatively coupled to a distal end of the nozzle assembly; an articulation connector having a proximal end operatively coupled to a distal end of the proximal closure tube; a surgical end effector comprising a first jaw and a second jaw and having a proximal end operatively coupled to a distal end of the articulation connector; a flexible shaft circuit strip disposed within at least a portion of the proximal closure tube, at least a portion of the articulation connector, and at least a portion of the surgical end effector; a knife member slideably disposed within the surgical end effector; and a knife bar operatively connected to a proximal end of the knife member, wherein the knife bar comprises a first laminated plate disposed on a first side of the flexible shaft circuit strip and a second laminated plate disposed on a second side of the flexible shaft circuit strip, and wherein the knife bar is configured to reciprocate along a longitudinal axis of the proximal closure tube; and characterised in that the first laminated plate is configured to reciprocate along the first side of the flexible shaft circuit strip and the second laminated plate is configured to reciprocate along the second side of the flexible shaft circuit strip.