A surgical instrument comprising: a housing; a shaft extending from the housing and defining a longitudinal axis ("L"); an end effector operably coupled to a distal portion of the shaft; and a gearbox assembly disposed within the housing and including an articulation sub-assembly configured to articulate the end effector about the longitudinal axis defined by the shaft, the articulation sub-assembly including: a first lead screw including a gear portion, a waist portion, and an elongate threaded body portion; and a first nut threadingly engaged with the elongate threaded body portion of the first lead screw such that rotation of the first lead screw effects longitudinal translation of the first nut; wherein the articulation sub-assembly further comprises: a second lead screw including a gear portion and an elongate threaded body portion; a second nut threadingly engaged with the elongate threaded body portion of the second lead screw such that rotation of the second lead screw effects longitudinal translation of the second nut; a middle plate including a middle plate stem extending proximally therefrom; a proximal center gear operably coupled to and rotatable around the middle plate stem and including a proximal gear portion and a distal gear portion, the distal gear portion of the proximal center gear meshingly engaged with the gear portion of the first lead screw; and a distal center gear operably coupled to and rotatable around the middle plate stem and including a proximal gear portion and a distal gear portion, the distal gear portion of the distal center gear meshingly engaged with the gear portion of the second lead screw and the proximal gear portion of the distal center gear aligned with the waist portion of the first lead screw. a housing; a shaft extending from the housing and defining a longitudinal axis ("L"); an end effector operably coupled to a distal portion of the shaft; and a gearbox assembly disposed within the housing and including an articulation sub-assembly configured to articulate the end effector about the longitudinal axis defined by the shaft, the articulation sub-assembly including: a first lead screw including a gear portion, a waist portion, and an elongate threaded body portion; and a first nut threadingly engaged with the elongate threaded body portion of the first lead screw such that rotation of the first lead screw effects longitudinal translation of the first nut; a first lead screw including a gear portion, a waist portion, and an elongate threaded body portion; and a first nut threadingly engaged with the elongate threaded body portion of the first lead screw such that rotation of the first lead screw effects longitudinal translation of the first nut; wherein the articulation sub-assembly further comprises: a second lead screw including a gear portion and an elongate threaded body portion; a second nut threadingly engaged with the elongate threaded body portion of the second lead screw such that rotation of the second lead screw effects longitudinal translation of the second nut; a middle plate including a middle plate stem extending proximally therefrom; a proximal center gear operably coupled to and rotatable around the middle plate stem and including a proximal gear portion and a distal gear portion, the distal gear portion of the proximal center gear meshingly engaged with the gear portion of the first lead screw; and a distal center gear operably coupled to and rotatable around the middle plate stem and including a proximal gear portion and a distal gear portion, the distal gear portion of the distal center gear meshingly engaged with the gear portion of the second lead screw and the proximal gear portion of the distal center gear aligned with the waist portion of the first lead screw. a second lead screw including a gear portion and an elongate threaded body portion; a second nut threadingly engaged with the elongate threaded body portion of the second lead screw such that rotation of the second lead screw effects longitudinal translation of the second nut; a middle plate including a middle plate stem extending proximally therefrom; a proximal center gear operably coupled to and rotatable around the middle plate stem and including a proximal gear portion and a distal gear portion, the distal gear portion of the proximal center gear meshingly engaged with the gear portion of the first lead screw; and a distal center gear operably coupled to and rotatable around the middle plate stem and including a proximal gear portion and a distal gear portion, the distal gear portion of the distal center gear meshingly engaged with the gear portion of the second lead screw and the proximal gear portion of the distal center gear aligned with the waist portion of the first lead screw.