A surgical instrument including a housing, a shaft, an end effector assembly, a first electrical wire, and a wire guide. The shaft defines a lumen and extends distally from the housing. The end effector assembly is disposed at a distal end portion of the shaft and includes a first electrically-conductive tissue-treating surface. The first electrical wire extends from the housing, through the shaft, and into electrical communication with the first electrically-conductive tissue-treating surface. The electrical wire is adapted to connect to a source of energy and configured to supply energy to the first electrically-conductive tissue-treating surface. The wire guide is disposed within the housing and engaged about a proximal portion of the shaft within the housing. The wire guide is also configured to guide the first electrical wire from the housing into the shaft.