We chiropractors have long endured the mystery of why almost half our whiplash patients experience long-term symptoms. Finally, researchers may have some answers for us. They published the following study in the Pain Journal in July 2022.
The study looked at 54 prior studies, including almost 400,000 patients. 34% of the patients answered questionnaires indicating they suffered from neuropathic pain. Without regard to the severity of their whiplash associated disorder (WAD), these patients showed significant loss of sensory perception in their index finger compared to the control group. But diagnostic tests caught only 13% as having neuropathic injuries.
This matters because the most common WAD diagnosis lacks a neurological finding. This study indicates that only about 1/3 of neuropathy cases were correctly diagnosed. Had healthcare professionals examined the index fingers of the patients, doctors may have properly diagnosed all cases.
The conditions reported as loss of sensory perception in the index finger include:
Inability to detect light touch
Inability to feel vibrations
Inability to detect temperature changes
While sensory dysfunction was the greatest in the index finger, there was lesser dysfunction shown in the thumb. The impact of the injury, as classified by the current WAD severity ratings, was not a predictor of whether neuropathic issues were present. It doesn’t matter if the patient is classified as:
WAD I — mild symptoms without physical signs
WAD II — symptoms and signs without nerve injury
WAD IV — broken bones
In any of these cases, the patient could have neurological damage that goes undetected under our current system.
As neuralgic pain may be the source of chronic WAD, it’s a good idea to perform a neurological test before issuing a diagnosis. The primary factor to look for is loss of sensory function in the index finger and thumb. Where these symptoms appear, there’s a high probably of neurological damage.
Of course, for many, it’s counterintuitive to look at a finger to assess the likelihood of long-term pain from whiplash. But until we have better data, that is probably just what we should all be doing.
This diagnostic approach can be as simple as a two-point discrimination of the fingers, pressure pain thresholds, neurodynamic testing, and questionnaires to track progress.
With an accurate diagnosis, we can prescribe an effective treatment to mitigate the risks and effects of chronic WAD. We need more data, but for the moment, it’s probably a good idea to add these tests before trying to classify the severity of whiplash injuries.