Always possible. Positioning animals under anesthesia is always done gently but animals, just like humans, are at their most relaxed during anesthesia. That means that the simplest and gentlest of maneuvers can sometimes occasion the movement of a prdisposed disk to "pop" out of its proper place. The key thing to understand, when it stresses you out to think that someone might have hurt your baby, is to understand that it probably would've happened anyway. Discs that are ready to blow will blow all by themselves, too.