US Patent 9254170 Electrosurgical device with disposable shaft having modular subassembly

An apparatus comprises an end effector, a shaft assembly, and an interface assembly. The end effector is operable to manipulate tissue, the shaft assembly is in communication with the end effector and a portion of the shaft assembly extends proximally from the end effector. The interface assembly is in communication with the shaft assembly. The interface assembly comprises a housing portion, a shaft cartridge, and a base portion. The housing portion can engage the shaft cartridge. The shaft cartridge is able to rotate and articulate the end effector, and the shaft assembly extends from the shaft cartridge. The base portion and the housing portion are able to enclose the shaft cartridge.