This can be caused by damage or irritation of virtually all tissues in the low back region including the discs, facet joints, ligaments, sacro-iliac joints, lumbar nerve roots, the dura and bone. Chemical or mechanical factors, mediated by inflammation, stimulate the pain receptions.
It is also important to remember that low back pain can also be caused by irritation to the many organs lying near the lumbar spine – such as kidneys, prostate, pancreas, abdominal aorta, gastro-intestinal tract and gynaecological organs – and therefore have no musculo-skeletal cause. Bone cancer, joint infection or inflammatory arthritis can also lead to low back pain. However, it is mechanical/musculoskeletal back pain that is the most common culprit –“bad discs” and the like.
So musculoskeletal back pain can be thought of as inflammation arising on a long-term background of wear and tear in the joints and discs of the spine. There are 2 general patterns:
Continuous low back pain/ache – CLBP
The process is chronic and ongoing and symptoms are relatively constant and persistent. The pain is generally provoked after exercise, made worse by prolonged sitting or driving and is often worse in the morning especially after a heavy day. It gets worse as the working week goes on.
Acute relapsing low back pain – ARLBP
Here, episodes of inflammation wax and wane. A trivial normal action, often as benign as bending over to pick up the soap or to tie a shoe lace, triggers a tweak which develops over the following hours into incapacitating back pain. Some may even have an instantaneous agony that leaves them crawling for the bed. The attacks may last a few days or a few weeks and will often begin with episodes occurring once every few years. Patients describe an absolutely normal pain-free life being intermittently placed on hold by episodes of acute, unpredictable agony. As time passes, the episodes may fail to fully resolve so there is an element of continuous low back pain that frequently escalates into episodes every few months. Some get into a severe episode which will not settle.