D. C. s employ a variety of elaborate X-ray marking systems and techniques to determine misalignments and make therapeutic choices. The practitioner takes a full spinal X-ray, compares it with an idealized version of the spine, then measures how much the patient's vertebrae deviate from the ideal. To me, this lacks a rational basis, since there's little evidence that slight postural distortions are correlated with back pain. Treatments vary from accepted to absurd The natural course of common back problems has been well-described in the medical literature. Only a small percentage go on to have unremitting chronic pain.
Chiropractic therapy tends to parallel the normal course of untreated back pain.
The practitioner might see a patient three times a week for a month, twice a week for another month, then once a week for a third month. When the pain resolves, the patient attributes it to the treatment. And, in fact, scientific studies demonstrate that spinal manipulation can accelerate the resolution of such pain. But there are plenty of chiropractors who won't stop treatment at that time. Then there are those who tackle problems that may exceed their capabilities.