What is discogenic low back pain?

  Low back pain is a common clinical condition, and there are many causes of lower back pain. In our daily treatment work, we gradually find that there is a group of patients with low back pain with special symptoms, which are neither accompanied by lower limb symptoms like lumbar disc herniation, nor can be relieved by simple treatment like simple lumbar muscle strain. These patients have low back pain, cannot sit or bend over for long periods of time, and their symptoms are repeated, but there are often no obvious problems on imaging, and the effect of general treatment such as oral medication, physiotherapy and nerve block is not good. Until recent years, with the widespread use of MRI and discography technology, medical workers gradually realized that in the absence of disc herniation, only disc rupture can cause a special kind of lower back pain, which was named discogenic lower back pain, or discogenic low back pain, at the International Pain Conference.    The most important clinical feature of discogenic low back pain is the decrease of sitting tolerance, and the pain often increases when sitting. The reason why patients prefer to stand rather than sit is that the pressure in the disc is highest in the sitting position, especially in the sitting forward position, which can aggravate the pain. The pain is mainly located in the lower back, but sometimes it can also spread to the lower extremities, mostly accompanied by pain below the knee of the lower extremities, which can be unilateral. The most common aggravating factor is after exertion, and painful symptoms are worse in sitting than in standing or walking. However, there are no specific signs for diagnosis.  When the intervertebral disc is surrounded by a dense fibrous ring and the nucleus pulposus in the center is in a semi-fluid state, when the fibrous ring ruptures due to degeneration of the disc itself, trauma, strain and other factors, the nucleus pulposus fluid exudes from the rupture, causing sterile inflammation and stimulating the adjacent nerves, dural sac and other tissues, resulting in low back pain. In addition, after the rupture of the fibrous ring, the scar tissue will proliferate and the sinus vertebral nerve embedded in it will be stimulated, which will also cause low back pain.  The imaging characteristics of discogenic low back pain: (1) X-ray performance: conventional X-ray plain film examination is negative, and sometimes the narrowing of the intervertebral space, the formation of bone redundancy or vertebral instability can be seen.  (2) MRI: the high signal area behind the fibrous ring and the intervertebral disc show low signal, which is considered to be a sensitive manifestation of discogenic lower back pain. However, it cannot be used as the gold standard for the diagnosis of fibular ring tear and discogenic lower back pain. This is because MRI can be normal in 10% to 20% of patients with disc tears.  (3) Discography: discography is currently the most reliable means of diagnosing discogenic low back pain. The diagnosis of discogenic low back pain can be considered positive on discography only if the pain is induced and replicated on discography and the discography shows a tear in the annulus fibrosus: (1) with or without a history of trauma, with recurrent symptoms lasting more than six months; (2) with the typical clinical manifestations described above; (3) with a positive discography or an MRI showing a typical low signal in the intervertebral disc and a high signal area in the posterior part of the annulus fibrosus V. Treatment  Treatment: The principles of non-operative treatment for discogenic lower back pain are: change of activity, non-steroidal anti-inflammatory drugs, physiotherapy, epidural steroid injection and functional exercise. Non-operative treatment should be continued for a minimum of 4-6 months. After non-operative treatment, some patients can have their symptoms relieved, and some patients have poor results, at which time surgery can be considered. Traditional open lumbar disc surgery, collagenase myelolysis, laser disc ablation, and percutaneous discotomy and suction are not suitable for the treatment of discogenic back pain. At present, the better methods for treating this disease include lumbar spinal fiber ring radiofrequency angioplasty, lumbar spinal fiber ring radiofrequency thermocoagulation, intervertebral disc ozone ablation and other minimally invasive interventional therapies.