Theoretically, the tractioning or distraction of the disc combined with isolation and gentle pumping of the involved area allows the central area of the disc, the nucleus pulposus, to assume its central position in the disc. Flexion-distraction is thought to improve disc height.
These actions move the disc away from the nerve, reducing inflammation of the nerve root, and eventually the associated pain and inflammation into the leg.
Flexion-distraction is applied in a series of treatments combined with adjunctive physiotherapy, supplementation, and home instructions. Eventually, specific exercises for low back disc conditions are introduced. Patients are evaluated and monitored throughout the treatment program.
In flexion-distraction technique, chiropractors follow a "50% rule": if a patient has not improved objectively and subjectively by 50% at the end of 12 sessions, then imaging studies are assigned and spine specialist referral is considered. If there is substantial worsening at any time during treatment, imaging and neurosurgical referral are the standard of care.