What is the difference between aggravation, acceleration and coincidence?

What proves medical causation in an injury claim?

Not the imaging. The imaging shows the terrain. What carries causation is the documented change across a date.

• Temporal relationship — onset relative to the event, and whether the interval is biologically plausible for the mechanism claimed.
• Change in pattern — a new distribution, a new quality, a new radiation, or a new neurological sign that was absent before.
• Change in function — work, activity, medication, care-seeking. Employment and pharmacy records frequently document this better than the medical chart does.
• An identified generator — a structure named by block or by electrodiagnostic study rather than assumed from a report.
• Exclusion of alternatives — the competing explanations considered and addressed rather than ignored.

Is apportionment a defense to causation?

This is the point on which the most cases are lost, and it is a logical error rather than a medical one. Apportionment and causation are sequential questions, not alternative ones. You never reach apportionment until causation is already established, because dividing an injury into parts presupposes that there is an injury to divide.

Put plainly: an apportionment figure is an answer to “how much,” never to “whether.” A finding that half of a present impairment is attributable to a degenerative baseline is a finding that the other half is attributable to the injury. It is an allocation of responsibility, not an escape from it.

Three consequences follow, and they are worth stating separately because they get collapsed in argument.

• An aggravation is a new clinical state, not a louder version of an old one. A person who was working, sleeping and functioning on a degenerated spine, and who after an event is doing none of those things, has sustained something. The substrate was old. The disability is new, and the new part is what the event produced.
• A percentage does not travel backwards into the causation question. “Sixty percent pre-existing” is not a finding that the event caused nothing; it is a finding that the event caused forty percent of a present state that would not otherwise exist in this form.
• An unapportionable case is not an uncaused one. Where the medicine cannot separate baseline from increment — often because no pre-injury record exists — that is a limit on the precision of the allocation. It is not evidence that the injury did nothing, and a report that lets it be read that way has misstated its own findings.

The mirror overreach is just as real and gets less attention: inflating the traumatic increment, treating every present symptom as injury-related, and declining to apportion where a genuinely separable and independently progressing condition is documented. Both errors are corrected the same way — by naming what changed, when, and on what evidence.

How precise can medical apportionment be?

Attorneys sometimes want a percentage. There is rarely a medically honest one. Apportioning a symptom between a degenerative baseline and a traumatic increment is not a measurement; at best it is a structured estimate, and it should be labeled as one.

What can usually be stated with confidence is the direction and the fact of change: this patient had X before and Y after, the difference is Z, and the difference is consistent with the mechanism described. Where a genuine apportionment can be supported — usually because there is a good pre-injury record — it is given with its basis. Where it cannot, we say it cannot.

Pre-injury records are therefore not a threat to a case. They are the strongest single asset in one, and a file with none is harder to write about honestly than a file with unfavorable ones.

Does a gap in treatment hurt an injury claim?

A gap in treatment is read as absence of injury unless it is explained. The explanations are usually mundane: no insurance, no transport, a job that could not be missed, a referral that was never made, a denial. Those belong in the history, recorded at the time, from the patient’s own account.

Where a gap exists because the indicated treatment was not covered, that is a coverage fact rather than a clinical one — see coverage is not evidence.

This practice is not aligned to a side. Its obligation runs to the patient’s health and safety, which is the same reason it is not beholden to any position that would keep it from seeing what is actually there. We do not offer opinions on liability, we do not accept a referral or a review conditioned on reaching a particular conclusion, and we will say plainly when the evidence does not support the claim — whichever party was hoping otherwise.

Frequently asked questions

Can you give a percentage apportionment?

Sometimes, with a stated basis, usually where a pre-injury record exists. Often the honest answer is that the increment can be described but not quantified, and that is what the report will say.

Does a prior similar complaint end the case?

No. It changes the question to aggravation, which requires a documented change in pattern, intensity or function rather than a claim of prior perfect health.

How long an interval between crash and symptom onset is still plausible?

It depends on the mechanism and the tissue. Delayed onset over days is ordinary for some soft-tissue injuries; a months-long gap needs an explanation, and the explanation has to be in the record.

What if the pre-injury records are unfavorable?

Send them anyway. An opinion written without them does not survive their production in discovery — see records that survive cross.

What is medical causation?

Medical causation is the question of whether an injury produced the patient’s present condition. It comes before apportionment, which asks how much of that condition the injury accounts for. A causation opinion rests on the documented change across the date of the event — timing, pattern, function, an identified pain generator and alternatives excluded — not on the imaging alone, which only shows the terrain.

How do you prove aggravation of a pre-existing condition?

By documenting what changed across the date of the event: a new distribution, quality or radiation of pain, a new neurological sign, or a change in work, activity, medication or care-seeking. Pre-injury records are the strongest single asset, because they show the baseline. A prior similar complaint does not end the case; it turns the question into aggravation rather than a claim of prior perfect health.

Is causation hard to prove?

It is hardest when a file leans on imaging alone or has no pre-injury record. A scan shows the terrain, not the cause. Causation holds when the record shows onset timing that fits the mechanism, a change in pattern and function, a pain generator named by block or electrodiagnostic study, and competing explanations considered and addressed rather than ignored.

Related reading

• The eggshell plaintiff
• “Pre-existing degeneration”
• Imaging and correlation
• Records that survive cross
• Objective corroboration