An articulation assembly (200, 520, 700) for a surgical instrument, comprising: first, second, third, and fourth lead screw assemblies (340, 350, 360, 370, 540), each lead screw assembly including a lead screw (342, 542) and a collar (346, 546) operably engaged about the lead screw such that rotation of the lead screw translates the collar about the lead screw, wherein the lead screws (342, 542) of the first and third lead screw assemblies (340, 360) define equal and opposite thread-pitches relative to one another and wherein the lead screws (342, 542) of the second and fourth lead screw assemblies (350, 370) define equal and opposite thread pitches relative to one another; first, second, third and fourth articulation cables having respective proximal ends operably coupled to the collars of the first, second, third, and fourth lead screw assemblies (340, 350, 360, 370, 540), respectively, such that proximal movement of one of the collars (346, 546) about the respective lead screw (342, 542) pulls the corresponding articulation cable proximally and such that distal movement of one of the collars (346, 546) about the respective lead screw pushes the corresponding articulation cable distally; first, second, third and fourth proximal gear assemblies (240, 250, 260, 270) coupled to the lead screws (342, 542) of the first, second, third, and fourth lead screw assemblies (340, 350, 360, 370), respectively; a first coupling gear configured to couple the first and third proximal gear assemblies (240, 260) with one another such that the lead screws (342, 542) of the first and third lead screw assemblies are constrained to rotate in the same direction and, thus, such that the collars (346, 546) of the first and third lead screw assemblies are constrained to move in opposite directions; and a second coupling gear configured to couple the second and fourth proximal gear assemblies (250, 270) with one another such that the lead screws (342, 542) of the second and fourth lead screw assemblies are constrained to rotate in the same direction and, thus, such that the collars (346, 546) of the second and fourth lead screw assemblies are constrained to move in opposite directions, characterized in that the first coupling gear is insertable between the first and third proximal gear assemblies (240, 260) in meshed engagement therewith after pre-tensioning of the first and third articulation cables to thereby maintain the first and third articulation cables in pre-tension, and the second coupling gear is insertable between the second and fourth proximal gear assemblies (250, 270) in meshed engagement therewith after pre-tensioning of the second and fourth articulation cables to thereby maintain the second and fourth articulation cables in pre-tension. first, second, third, and fourth lead screw assemblies (340, 350, 360, 370, 540), each lead screw assembly including a lead screw (342, 542) and a collar (346, 546) operably engaged about the lead screw such that rotation of the lead screw translates the collar about the lead screw, wherein the lead screws (342, 542) of the first and third lead screw assemblies (340, 360) define equal and opposite thread-pitches relative to one another and wherein the lead screws (342, 542) of the second and fourth lead screw assemblies (350, 370) define equal and opposite thread pitches relative to one another; first, second, third and fourth articulation cables having respective proximal ends operably coupled to the collars of the first, second, third, and fourth lead screw assemblies (340, 350, 360, 370, 540), respectively, such that proximal movement of one of the collars (346, 546) about the respective lead screw (342, 542) pulls the corresponding articulation cable proximally and such that distal movement of one of the collars (346, 546) about the respective lead screw pushes the corresponding articulation cable distally; first, second, third and fourth proximal gear assemblies (240, 250, 260, 270) coupled to the lead screws (342, 542) of the first, second, third, and fourth lead screw assemblies (340, 350, 360, 370), respectively; a first coupling gear configured to couple the first and third proximal gear assemblies (240, 260) with one another such that the lead screws (342, 542) of the first and third lead screw assemblies are constrained to rotate in the same direction and, thus, such that the collars (346, 546) of the first and third lead screw assemblies are constrained to move in opposite directions; and a second coupling gear configured to couple the second and fourth proximal gear assemblies (250, 270) with one another such that the lead screws (342, 542) of the second and fourth lead screw assemblies are constrained to rotate in the same direction and, thus, such that the collars (346, 546) of the second and fourth lead screw assemblies are constrained to move in opposite directions, characterized in that the first coupling gear is insertable between the first and third proximal gear assemblies (240, 260) in meshed engagement therewith after pre-tensioning of the first and third articulation cables to thereby maintain the first and third articulation cables in pre-tension, and the second coupling gear is insertable between the second and fourth proximal gear assemblies (250, 270) in meshed engagement therewith after pre-tensioning of the second and fourth articulation cables to thereby maintain the second and fourth articulation cables in pre-tension.