If a crash on I-29 or I-90 turned a manageable back problem into something that now threatens your CDL, the insurance company does not get to shrug and say, "your back was already bad."

They will try it anyway.

That old MRI. That note about degenerative disc disease. That chiropractor visit from three winters ago after you slipped on ice in Mitchell or tweaked your back chaining up in the Black Hills.

They will drag all of it out and act like the wreck didn't change anything. This is where a lot of South Dakota injury claims get ugly, especially for truckers, because your body already has miles on it and your medical file probably isn't clean like some 22-year-old office worker's.

A pre-existing condition does not let them off the hook

South Dakota law does not require you to have a perfect spine before somebody crashes into you.

If you had a vulnerable back, and this collision made it worse, that worsening still counts.

That is the basic idea behind what people call the eggshell plaintiff rule. The defendant takes you as they find you. If your low back was already worn down and a crash on a windy stretch near Brookings, Watertown, or Sioux Falls turns that into radiculopathy, leg weakness, or a fusion recommendation, they are still responsible for the harm they caused.

Not for every ache you ever had since age 30.

But for the aggravation. The acceleration. The new limits.

That distinction matters.

The game they play with "degenerative" findings

Here's what most people don't realize: a whole lot of adults have scary-sounding MRI language.

Disc bulge. Degenerative changes. Stenosis. Arthropathy.

Insurers love those words because they sound old, chronic, and not crash-related. They'll hand that MRI to a hired doctor who never met you before and say your pain was "preexisting" and the wreck only caused a temporary strain.

For a long-haul driver, that is a brutal argument because your damages are not just a medical bill and a few sore weeks. If your symptoms now make it hard to sit for 8 hours, climb into the cab, secure loads, pass a DOT physical, or safely handle an air-brake stop, the injury reaches straight into your license, your route, and your future.

And the adjuster knows that.

They are counting on you sounding embarrassed about your prior back history. Don't do that.

A prior condition is not a confession that this wreck didn't hurt you.

What actually proves aggravation of a prior injury

The biggest issue is not whether you had an old back problem.

It's whether your life changed after this crash in a way that can be tracked.

That usually means a before-and-after story that is specific, boring, and hard to wiggle out of. Not dramatic. Detailed.

The strongest facts are usually things like:

• you were driving regular loads before the crash and now cannot sit through a run without numbness, pain, or stopping every hour
• you had occasional back pain before, but no leg symptoms, no missed work, and no surgical talk until after the collision
• your old MRI showed wear-and-tear, but your new symptoms started right after the wreck on a specific date
• your treatment escalated after the crash: injections, work restrictions, new imaging, surgical consults, failed physical therapy

That is how you pin down the difference between "I had a worn back" and "this crash wrecked what was still functioning."

Insurance companies blur those two things on purpose.

Why truckers get hit harder by this argument

A guy living in his cab five days a week does not need to be bedridden to be seriously injured.

He just needs to lose the physical margin his job depends on.

A back that was "good enough" before is not good enough now.

That matters even if you kept working for a while. A lot of drivers push through pain because missing loads means missing rent, child support, truck payments, or the little bit of breathing room they have left. Then the insurer uses that against them too: "See? He kept driving."

Of course he did.

People in South Dakota work hurt all the time. Meat plants, warehouses, feedlots, road crews, trucking. That doesn't mean they're fine. It means bills keep showing up.

South Dakota fault law makes the blame fight even meaner

South Dakota is an at-fault state, and blame matters. If the insurer can combine the "bad back already" argument with a claim that you were partly at fault on an icy road, in crosswind, or in a ground blizzard on I-90, they'll do both.

They may say you overreacted, braked wrong, drove too fast for conditions, or failed to avoid the hazard.

That is not random.

If they can make your injury sound old and make the crash sound partly your fault, they cut the value from both sides. South Dakota's comparative fault system is unforgiving once they convince people you carry too much of the blame.

So the medical history fight is never just about medicine. It is about money.

The phrase you need to keep in your head

The useful phrase is not "I never had back problems."

That blows up the second they find an urgent care note from Aberdeen or Rapid City.

The accurate phrase is: I had prior back issues, but I was functioning, working, and not dealing with these symptoms until the crash made it worse.

That is honest.

And honesty plays better than pretending you were built brand new.

If your old records show flare-ups, that's fine. The question is whether this wreck changed the level of pain, the kind of symptoms, the treatment path, and your ability to keep your CDL life together.

If before the crash you were hauling. If after the crash you are looking at injections, restrictions, lost runs, and somebody tossing around "fusion" like it's no big deal.

That is not the same injury.

That is an aggravated injury, and South Dakota law does not let an insurer erase it just because your spine had some age on it already.