A Practical Approach to the Diagnosis and Understanding of Chronic Low Back Pain, Based on Its Pathophysiology.

As outlined abundantly in this book, chronic low back pain is not a diagnosis, but a symptom. Thorough knowledge of the cause and nature of the pain might help when looking for a correct diagnosis. Often, this clinical knowledge is more important with respect to therapeutic strategies than advanced medical tools such as imaging. When evaluating the cause of the pain, one should always be aware that much of the pain presented by the patients might be referred pain, by which pain patterns from various sources (e.g., lumbar facet joints and sacroiliac joint) may mimic each other. Thus, deep somatic pain derived from spinal structures may refer to the legs, even beyond the knee, and is not Always restricted to the back. However, it is clear that the location of the pain provides no reliable identification of the primary source of pain. Even identification of the tissue source of pain is hazardous. This might be a major additional explanatory factor for the reason why the specifi city of pain/tissue source vs. pain symptomatology is low. Although diagnostic nerve blocks may be helpful, several limitations (technical, sensitivity, and specificity) have been reported. The same accounts for advanced medical imaging, such as MRI and single-photon emission tomography (SPECT)-CT. Thus, the certainty by which a diagnosis can be made is not so high as the physician and the patient would wish it to be, but that is something we will have to live with for a few more decades. Furthermore, this overlap in symptoms and diagnoses caused by the multisegmental innervation of spinal structures also leads to a poor homogeneity in patient groups in randomized controlled trials, especially when patient numbers are low. Often we compare apples with pears and are surprised that our results do not correspond to what we expect. A more proper diagnosis is the only correct answer to this problem. Much more research should be directed toward diagnosis, rather than to more fancy therapeutic tools. We should search for biomarkers that can be correlated with a specifi c treatment and excellent clinical outcome. We are afraid, however, that research for more fl ashy implants is more rewarding than the one for a proper diagnosis. Finally, pain should be considered as the resulting experience of activation of the peripheral nerve endings and neurons at the spinal ganglions, the spinal cord, the brain stem, and the brain. At the level of the brain, these neurons deal with the translation of nociceptive stimuli and value the unpleasantness of incoming signals. The balanced end result can be experienced as pain, but not always, since this interpretation process may be influenced by many other factors. We are just at the beginning of the exploration of this very complex and multifaceted pathophysiology of pain. While therapies have changed very little in the past decades, clinical practice of chronic pain management has undergone a paradigm shift. The emerging focus is on helping people to live with their pain. Providing pain relief for alle patients is abandoned, since not realistic today