Apparently, Starfleet calls certain types of nebula "Mutara type", no doubt after the first one of that type encountered. And apparently this namesake nebula is the one from TWOK, but the galaxy is full of other nebulae of that type.
BTW, the use of stasis to protect the crew within that nebula suggests that this particular type of stasis slows down life processes considerably, probably to a near-standstill not practically discernible from death. This would be a valid mechanism for keeping radiation damage in check: mutated cells would not divide and multiply... Yet this is also the shallowest type of stasis ever shown on screen.
Good point that medical stasis was used in "Genesis". So there isn't a total technological or ethical ban on that procedure. There may still be two kinds of obstacles, though:
-Practical aspects: perhaps a single EMH isn't capable of handling a stasis operation - perhaps a whole stasis team, comparable to today's surgery teams, is needed for that?
-Medical aspects: certain types of injury might be incompatible with stasis.
With medical matters, it's always possible to write in an incurable disease, no matter how many other diseases are curable. It's also simple to write in a fatal internal injury when other types of internal injury are nonfatal. Things become dramatically iffy only when one episode clearly shows that a limb cut off or some other external, easily visible injury is no problem, but another claims that another limb lost or another exterior spot injured is a problem. This unfortunately happens in Trek as well: sometimes stab wounds are trivial, even when going through the heart (Picard, "Tapestry"), while at other times they are untreatable (Armin Maaritza, "Duet"). And sometimes phaser burns to the torso are shrugged off, but at other times they automatically end the life of the expendable/guest character (DS9 went back and forth on this a lot).
Anyway, in the case of Kim and Jetal, we could certainly argue that there were internal injuries we can't argue about, so to speak. The chance of something stasis-counterindicating is definitely there - and the fact that it is not specifically mentioned does not lead into a plot hole or contradiction at all. The EMH should know what he's capable of doing and what he is not, without bothering us with the details.
Timo Saloniemi