Helical trauma was serious bodily injury resulting from being twisted into a spiral or helix shape.
In 2256, Paul Stamets described the contorted-deaths of the crew of the USS Glenn as having suffered "helical trauma," which caused their bodies to be twisted and torn apart when the ship hit a Hawking radiation firewall while exiting the mycelial plane. (DIS: "Context Is for Kings")
The effect was caused by interacting with the mycelial barrier outside of the safety of the reaction cube. Anyone touching the barrier in such a manner would find themselves twisted around the axes of both mycelial space and normal space. (DIS: "Saints of Imperfection")