Review of Lumbar Discogenic Pain Annular Disc tear

A Review of Lumbar Discogenic Pain

Low back pain is a common ailment that can have various causes. While fractures, tumors, and infections are rare contributors to low back pain, the exact reasons behind its occurrence are not always apparent. Philosophers and scientists have put forth different explanations for back pain, ranging from psychosocial factors to nociceptive phenomena. To further understand these questions, a review of lumbar discogenic pain critically looked at previous studies to determine whether or not discs themselves can hurt and whether we can accurately test that. 

Determining discogenic pain 

Determining discogenic pain as a diagnosis can be challenging due to the absence of a physical reference standard. However, alternative processes can be employed for this purpose. Stimulation tests have been utilized as a diagnostic tool for discogenic pain, but their validity depends on specific criteria. 

These criteria include ensuring the tests do not yield positive results in normal volunteers and are not positive for reasons other than symptomatic discs. Studies involving normal volunteers have been conducted to ascertain the effectiveness of disc stimulation. Interestingly, abnormal discs were found in asymptomatic individuals but were more prevalent in patients experiencing back pain.

Central hyperalgesia is a competing hypothesis that posits any stimulated structure will elicit pain. Nevertheless, studies have demonstrated that patients can differentiate between symptomatic and asymptomatic discs. Psychometric tests have also been conducted to assess the influence of psychological distress on disc stimulation, but the results have been inconsistent. 

Some patients with elevated scores on psychometric tests or abnormal pain drawings have exhibited exaggerated responses to disc stimulation. However, not all patients with these characteristics have displayed abnormal responses. Consequently, while disc stimulation remains a valid diagnostic test for back pain, the influence of psychometric features on the interpretation of results should be taken into consideration.

Other indicators of painful discs

Discitis, although rare, is a condition that causes severe pain and challenges the notion that lumbar discs cannot be a source of pathology-induced pain. Another condition known as internal disc disruption involves the degradation of the nuclear matrix and the development of fissures within the disc, which strongly correlate with pain. 

Discs with grade III or IV fissures are more likely to be painful, whereas discs with no fissures or only grade I or II fissures are less likely to be a source of pain. Internally disrupted discs exhibit abnormal biomechanical properties, with reduced stress on the nucleus and increased stress on the annulus, which correlate with pain reproduction during disc stimulation.

Mechanical nociception resulting from stress on the posterior annulus and chemical nociception caused by inflammatory chemicals and noxious agents are potential mechanisms of pain in internally disrupted discs. 

High-intensity zone (HIZ) lesions and Modic lesions observed on magnetic resonance imaging (MRI) strongly correlate with painful discs upon disc stimulation. HIZs manifest as spots of intensely high signal within the posterior annulus, indicating significant radial or circumferential fissures. 

Modic changes, on the other hand, appear as patches of abnormal signal in the vertebral bodies adjacent to the disc. Prevalence studies indicate that internal disc disruption occurs in a substantial proportion of patients with chronic back pain, ranging from 26% to 42%.

Developments in research

Internal disc disruption is a well-researched cause of low back pain, supported by clinical, biomechanical, imaging, and animal studies. Researchers are actively working on developing an analgesic test for lumbar discogenic pain as an alternative to discography. Such advancements would offer new diagnostic and therapeutic possibilities for individuals suffering from low back pain, improving their quality of life and potentially leading to more targeted treatment approaches. 

Your discs can hurt

Understanding the complex nature of low back pain and its association with disc-related pathologies is a crucial step toward effective management and relief for those affected. But either way, anatomical and physiological evidence contradicts the notion that discs cannot be a source of pain. In fact, in patients with back pain, discs have been identified as a potential source of pain. For patients, a visual guide to the discs with the help of our models, can add a meaningful layer to treating and managing low back pain.