When back pain persists beyond the expected time for healing but no cause can be found, then it is called nonspecific. Imaging studies have likely shown that there is no tumor, fracture, or infection.
Soft tissue structures such as ligaments, muscles, and connective tissue are involved but it’s unclear which ones are at fault and what went wrong.
Physical therapists are starting to classify low back pain patients according to the movement impairment present. If bending forward (flexion) causes the symptoms or makes the pain worse, then a flexion pattern (FP) is named as the motor control impairment. If extending backwards hurts and forward flexion helps, then an active extension pattern (AEP) is named.
Researchers are starting to make headway in finding successful treatment methods using this subgrouping. EMG studies of muscle activity have also shown differences in motor control between the FP and AEP groups.
Future studies using subclassifications like this are expected to end the use of “nonspecific” as a diagnosis of low back pain. The true underlying soft tissue problem will be more clearly identified.