I. Diagnosis of intervertebral discogenic lower back pain
Discogenic lower back pain is an extremely common clinical condition, which is chronic lower back pain caused by intra-disc disorders (IDD) such as degeneration, intra-fibular ring fracture and discitis that stimulate pain receptors within the disc, without radicular symptoms, without radiological evidence of nerve root compression or excessive displacement of vertebral segments, and can be described as chemically mediated discogenic pain.
(I) Clinical features
The most prominent clinical feature of discogenic lower back pain is decreased tolerance to sitting, with pain often increasing in the sitting position, and the patient can usually only sit for about 20 minutes. The pain is mainly located in the lower back, and sometimes it can be dissipated to the lower extremities. 65% of them are accompanied by pain below the knee of the lower extremities, but there are no specific signs for diagnosis.
(II) Imaging features
1, MRI: T2-weighted images in the diseased discs all show low signal changes (disc darkening), and the presence of high signal areas behind the fibrous ring is a sensitive manifestation of IDD, but cannot be used as the gold standard for specific diagnosis. This is because MRI can be normal in 10% to 20% of patients with disc tears.
2, discography: discography is currently the most reliable means of diagnosing discogenic pain. Discography can be considered positive only if pain is induced and replicated during discography and if discography shows a tear in the annulus fibrosus. If there is only a tear of the annulus fibrosus or leakage of the contrast agent and the patient has no induced or replicated pain, it means that the disc may not be related to the patient’s pain.
The main indicators and determinations are as follows.
(1) Induced pain: Repeat the main symptoms, such as the nature of the pain, the site and extent of involvement.
(2) Increase in the volume of the nucleus pulposus (containing the amount of contrast medium), with the injection of more than 2 ml of contrast medium.
(3) Morphology of the contrast agent: the nucleus pulposus (contrast agent) has irregular morphology, uneven density, hairy edges, and occupies the whole or most of the intervertebral space. The common shapes of intervertebral disc tears are radial, concentric, and transverse.
(C) Diagnostic criteria
There is no gold standard for the diagnosis of discogenic lower back pain, and it is generally believed that the following conditions must be met.
1, with or without a history of trauma, with recurrent symptoms lasting >6 months;
2, the above-mentioned typical clinical manifestations ;
3, positive discography or MR showing typical lesions with low signal in the intervertebral disc and high signal area in the posterior part of the fibrous ring.
Diagnosis of discogenic neck pain
In a broad sense, discogenic neck pain can include all neck, shoulder and arm pain caused by disc lesions, but many of the resulting pains have corresponding names, such as cervical disc herniation, cervical disc degeneration stenosis, cervical spondylosis, etc. In recent years, cervical discogenic pain refers to pain caused by internal disorders of the intervertebral disc without radiating pain or segmental neurological dysfunction, and does not involve the adjacent spinal cord, nerve roots, or small joints. Discogenic neck pain is one of the common causes of chronic, intermittent neck and shoulder pain.
1.Clinical manifestations
(1) Clinical features: intermittent scapular region pain with dispersion to the head, neck, shoulder and upper arm, often accompanied by numbness, but without radicular pain and motor and sensory nerve dysfunction distributed along the dermatomes.
(2) Excluding common diseases causing neck pain: there are many causes of neck, shoulder and arm pain, and discogenic neck pain has no specific symptoms and signs. It is important to ask for medical history and careful physical examination when receiving consultation to exclude persistent neck and shoulder pain caused by serious diseases such as tuberculosis and tumor, radicular pain caused by common cervical disc herniation and morning stiffness and dull pain caused by ankylosing spondylitis and osteoarthrosis, and carefully distinguish lesions such as postural sprain.
2, imaging features Clinical imaging features are helpful in identifying common spinal and osteoarthritic lesions.
(1) Plain X-ray and CT of the cervical spine: pathological or physiological changes of the bone and joint, such as injury, inflammation, degeneration, and tumor, can be identified. CT can suggest the diagnosis of disc herniation and spinal stenosis, but for disc bulge without nerve root and spinal cord compression, whether it CT can suggest the diagnosis of disc herniation and spinal stenosis.
(2) MRI: good resolution of soft tissue provides physiological changes in disc water, thus showing the degree of disc degeneration. the T2-weighted image of MRI shows low signal in the diseased disc and normal signal in the adjacent normal disc. However, the low signal is a degenerative phenomenon, and it is difficult to determine which degenerated disc is the “responsible disc” for the neck pain. The presence of a high signal area in the posterior fibrous annulus of the disc has been reported to be diagnostic.
It is generally accepted that if the T2-weighted image of MRI shows a low signal in the diseased disc (black disc sign) and a high signal area in the posterior fibrous ring of the disc, then most of the discs can be diagnosed as pathologic and do not need to be re-imaged.
(3) Discography: anterolateral cervical approach, routine frontal and lateral radiographs to determine the location of the needle, an average of 0.5 ml of contrast agent (0.15-1 ml) is injected into the disc, and the presence of evoked pain and/or replication pain is considered positive.
There are two main types of post-contrast CT scan images.
(i) white mass-like or radiolucent tearing image of the contrast agent in the nucleus pulposus;
Haranta et al. found that CT discography was diagnostic in 80% of cases with degenerative disc disease without herniation and radiating pain.
3.Diagnostic criteria
The North American Spine Society believes that only discography-induced lower back pain can determine the diagnosis of discogenic low back pain, based on the diagnostic criteria established by the International Society for the Study of Pain. The following conditions should be present for the diagnosis of discogenic neck pain.
(i) A contrast-induced test of the diseased disc results in the patient experiencing evoked and/or replicated pain;
(ii) The adjacent discs do not show such pain on the evoked test;
(iii) The cervical spine has abnormal MRI T2-weighted images as described above, and the diagnosis is made when combined with the clinical presentation.