I found a very important article :

Doctor Modic(chairman of the Neurological Institute at the Cleveland Clinic)report a his research: 250 patients. All had MRI scans when they first arrived complaining of back pain or shooting pains down their leg, which can be caused by a herniated disc pressing on a nerve in the spine. And all had scans again six weeks later. Sixty per cent had herniated discs, the scans showed.In 13 per cent of the patients, the second scan showed that the herniated disc had become bigger or a new herniated disc had appeared. In 15 per cent, the herniated disc had disappeared. But there was no relationship between the scan findings at six weeks and patients’ symptoms. Some continued to complain of pain even though their herniated disc had disappeared; others said they felt better even though their herniation had grown bigger.

The question, though, was whether it helped the patients and their doctors to know what the MRI’s had found. And the answer, Dr Modic reported, is that it did not. The patients who knew recovered no faster than those who did not know. However, Dr Modic said, there was one effect of being told — patients felt worse about themselves when they knew they had a bulging disc.
.......................
Very interesting article and very important for back pain treatment.

Many studies have shown that findings of degenerative disease, malalignment of the spine, and other anatomic problems or deformities don't always cause symptoms. And the opposite is true, too -- patients with severe pain may have very normal looking X-ray, CT scan, or MRI results. Successful, evidence-based treatment may not depend on imaging results.In fact, sometimes patients who see the changes on imaging studies (or who are told about them) end up worse off. Their perception of health deteriorates. They start avoiding certain activities or movements that "might cause pain." The end-result is worse pain and decreased function. Not only that but the rates of surgery have increased two to three times what they were 10 years ago.

Growing number of patients not receiving tests such as x-rays and scans within recommended six weeks, figures showA growing number of patients are not receiving a diagnostic test such as an x-ray or ultrasound scan within the NHS's recommended six-week waiting time, official figures show

See full article

___________________________________________________________________________________________
Another research :

MRI, although a very important technology, should never take the place of a thorough medical history and physical examination. Also, there are often structural findings or "abnormalities" on MRI that are not clinically relevant and not necessarily related to a patient's symptoms. MRI findings must always correlate with the patient's clinical picture.
When we need tools to identify a possible herniated disk ,the simplest type of MR imaging or CT imaging can be used successfully. However, if you want to find out which disk is causing pain, which nerve is firing, which metabolites are present in abnormal amounts, or how well the spinal elements are functioning, MR will provide the answers

Source:http://www6.aaos.org/news/Pemr/releases/release_boiler.cfm?category=1&releasenum=714

The study, published in the Lancet today, suggests the use of radiography, MRI, or CT scans in patients with no indication of underlying conditions does not improve clinical outcomes.

Another critical study investigating MRIs found that "normal" patients, patients with no symptoms of back pain, often have "abnormal" MRIs. In fact, the study found that disc degeneration or bulging is seen in at least one third of patients in their 20s and 30s. In patients over 60 years old, disc degeneration or bulging is seen in almost every patient studied...and these are patients with no back pain.

Studies show that patients who have surgery get better faster but the final results (one year or more later) are the same as for patients who stuck it out and waited for the body to heal itself. However, any sign that pressure on the sciatic nerve is causing permanent damage requires surgical intervention.

There are a variety of ways the surgeon may treat this problem. The simplest and most common is a discectomy (removal of the disc). Microdiscectomy is becoming the standard method used for lumbar disc herniation.

The operation is done with a surgical microscope. The surgeon makes a very small incision in the low back. This surgery is minimally invasive. It is easier to perform, prevents scarring around the nerves and joints, and helps patients recover more quickly.

According to the recent study of orthopedic surgeons, younger doctors are less likely to order tests for defensive reasons than older, more experienced doctors. On the surface, this is a counterintuitive finding, since one would expect younger doctors to be more afraid of making a mistake and therefore more likely to practice defensively. But could it be that younger doctors are simply less likely to view imaging tests as defensive, considering them instead as the standard way to make a diagnosis?Spine MRIs can be very valuable tools but only if ordered for the appropriate reasons, put in proper clinical context, and correlated with other pieces of the puzzle. When it comes to back pain, they’re not the end all be all they’re cracked up to be. They’re barely the end some be some, as the American College of Physicians has made clear. In most cases, MRIs are unnecessary and delay proper treatment; at worst, they lead to potentially harmful interventions.

ScienceDaily (Nov. 30, 2011) — Physicians who have a financial interest in imaging equipment are more likely to refer their patients for potentially unnecessary imaging exams, according to a study presented November 30 at the annual meeting of the Radiological Society of North America (RSNA).