The present disclosure provides a surgical instrument, such as a tissue sealing instrument, having a staple cartridge with a staple pusher and a staple; and a drive member configured to translate distally through the instrument. The drive member includes a lateral projection configured to engage the staple pusher and drive the staple into tissue. The lateral projection of the drive member has a height substantially less than the height of the staple cartridge, thereby requiring less clearance as it translates through the staple cartridge. In addition, the lateral projection has a smaller footprint than conventional drive members resulting in a more compact distal tip on the staple cartridge, which allows for a more compact and maneuverable surgical instrument.