Spinal instability describes a condition in which there is too much movement or translation of one vertebral bone over (or under) another. The shift of the bone can be seen on X-ray when the spine moves — especially at the end of the spinal movement (e.g., bending forward/flexion or bending backward/extension).
There are clinical tests that are specific enough (able to identify when lumbar segmental instability is NOT the problem). But the tests have low sensitivity meaning they aren’t very good at identifying patients who DO have segmental instability.
According to a recent systematic review of studies published in this area over the last 60 years, the patient’s symptoms (pain with certain movements like rolling over or standing up straight) and the timing of those symptoms (worse when the weather changed) actually have the highest sensitivity/specificity (88 per cent/93 per cent).
The patient suffering from back pain as a result of lumbar segmental instability experiences a “catching” sensation when standing up straight after being bent forward. Another sensation described is one of the spine “slipping out” during spinal motion.
If any of this describes your symptoms, it’s likely your physician has made an accurate assessment of your problem. But if you have any doubts about the diagnosis or recommended treatment, there’s nothing wrong with getting a second opinion.
X-rays may be helpful if you have not already had any imaging studies. X-rays are not required and they do expose the patient to radiation, which is why they are not routinely ordered.
There are exercise programs for lumbar and trunk stability including core training that may be helpful. If you haven’t tried this approach, you may want to seek the help of a physical therapist as well.