The present disclosure provides a staple cartridge for a surgical instrument, such as a tissue sealing instrument. The staple cartridge includes a housing and one or more staple assemblies within the housing. The staple assemblies each include one or more staple pushers and associated staples. The staple pushers and housing include coupling elements configured to cooperate with each other to retain the staple assemblies to the housing prior to use in surgery. The coupling elements, along with other components of the cartridge and instrument, result in a smaller staple cartridge relative to conventional devices, allowing for a more compact and maneuverable surgical instrument.