Spears can be used to inflict fairly deep cuts, but the primary, and lethal, injury is going to be deep penetrating strikes. If you want more detail, your best bet would be looking into industrial accidents involving impalement. Though, as we mentioned earlier; penetration is very lethal on a battlefield.
Beyond that, there were a lot of other polearms. Bladed ones like the halberd, voulge, bardiche, or glaive could carve up someone pretty badly, while keeping them at range.