I'm not sure if this counts, but in 2010, I twisted a vertebra in my neck from riding. No impressive unintentional dismount, just a lot of unexpected immediate stops and hitting my butt too hard in the saddle over the course of a couple of months. It did not cause any neck pain, but I had the worst headache I hope to ever experience. After 3 ER trips to figure out the cause, I was told to go to my chiro, who promptly asked if I was in a severe car accident.
The occasional teleport or dead stop throws my neck out of place, but nothing to that extent again.