According to one aspect, a fastening device may include a coupling body having (1) a portion configured to couple to a distal end of a medical device, (2) a cartridge holder, and (3) an anvil pivotably coupled to the cartridge holder. The cartridge holder and the anvil may extend distally from the portion and may be configured to extend distally of a distalmost face of the medical device when the portion is coupled to the distal end of the medical device. A flexible member may be configured to extend through a channel of the medical device. A fastener cartridge may be coupled to a distal end of the flexible member, including at least one fastener, and may be configured for releasable coupling to the cartridge holder.