Insertion junctures were components of Borg autonomous regeneration sequencers. The separation of the sequencer conduits from the insertion juncture was critical to the deactivation of the regeneration sequencers.
In 2374, while attempting to remove a number of Borg components from the USS Voyager, Lieutenant Torres and Ensign Kim experienced difficulty due to the fact that the regeneration sequencers would automatically regrow any removed component. Seven of Nine was eventually able to instruct them as to the proper procedure of deactivating the sequencers. (VOY: "The Gift")