A Classic Acute Lower Back Pain Case
Two weeks and five Physio sessions ago, a fit and healthy 45 year old woman came to see me for severe and disabling lower back pain. The pain was on her left side and spread to her left buttocks and down the back of her thigh to the knee. Her pain began insidiously. Although there was no event or trauma that triggered the onset of symptoms, she did report that she had been unwell for the week or so preceding the onset of symptoms. She had been more sedentary than normal and had been coughing frequently.
She previously came to see me for left sided lower back pain a few months ago. This earlier episode was her first experience of lower back pain. It also began insidiously but was not as severe or disabling as her current symptoms. It resolved with three sessions of treatment. For both the previous and current episode, the patient, lets call her Sophie, had a significant lateral shift to the right side in standing. In the current episode it was more severe. Sophie’s movements were severely hampered. She was unable to stand tall, unable to sit for more than a minute or two, and she could not lie down on her left side at all. She also reported a pins and needles sensation over her left buttock.
Sophie’s symptoms and movement limitations are best explained by an irritation of her left S1 nerve root, perhaps as a consequence of an acute injury to her L5/S1 intervertebral disc or facet joint. Her laterally shifted posture could be interpreted as a reflexive attempt by Sophie’s body to unload and protect her injured body tissues from further compression and irritation. She is feeling pain as a consequence of the injury itself but also as a consequence of her body’s own protective mechanisms which bring about a degree of nerve sensitivity and muscular guarding. Importantly, the initial injury itself can be quite minor, meaning that Sophie’s severe pain is likely mostly a result of her body’s protective response to the injury.
This a very common presentation of symptoms. Nearly always, this injury follows a predictable trajectory of recovery. Initially, there is a period of severe, disabling pain where basic movements such as getting out of bed, siting, rising from sitting, bending at the waist or standing tall are very difficult. This period of usually lasts a few days. As inflammatory processes begin to subside and muscular guarding begins to lessen, movements become a little freer and less painful. By about week to ten days following the initial onset of symptoms, most report that they feel about “65% back to normal”. By this stage people can usually walk normally but will still have difficulty with prolonged sitting and will find it difficult to get up and moving if they have been static for more than 20-30min.
In Sophie’s case, there was no traumatic event or incident that triggered her symptoms. So the likelihood that she has a significant structural injury in her spine is low. I suspect that if we were to do an MRI of her lumbar spine, we may see evidence of some degenerative changes to her L5/S1 intervertebral disc. Perhaps with her recent bout of illness and frequent coughing, she managed to irritate the L5/S1 disc and set off a sequence of inflammatory processes that ultimately triggered her body to suddenly become “protective”.
Over the two weeks that Sophie has been attending Physio, my focus has been on helping Sophie understand that it is unlikely that her injury is as severe as her pain may be leading her to believe. I have been reiterating that the severity of her pain is partly (perhaps mostly) explained by her own body’s capacity to ramp up its sensitivity to movement and load. So long as her body is in a sensitive, protective state, her movement and function is likely to limited and painful. With this in mind, we have been implementing treatment that serves the purpose of reducing her body’s movement sensitivity with gentle manual therapy and appropriate exercises for her to do at home.
To date, Sophie’s back pain has resolved 100%. And she is now able to move through a full range of motion into forward bending, backwards bending and side-bending. She however, still dealing with pain in the buttock region, with occasional spreading to the back of her thigh. She also is still experiencing some tingling in the buttock region. It appears that her body has let go of much of the muscular guarding that was initially limiting her movement, but she still has symptoms that suggest her S1 nerve root remains irritated.
I hope to see an ongoing reduction in these “nervey” symptoms over the coming weeks. It’not uncommon for such nerveroot symptoms to hang around for months after one of these lower back pain episodes. However, if these symptoms plateau and are preventing Sophie from participating in her normal daily activities, I will speak with her about a possible MRI to rule out the presence of structural pathology in the lower back that may require further investigation +/- review by a spinal or neurosurgeon. In my experience I would estimate that less than 1% of the cases of lower back pain end up requiring a surgical solution.
It’s now a week since I wrote the post above. Sophie is now three weeks and 6 physio sessions post onset of symptoms. She reported that over the past week, particularly the past 3 days, her symptoms have significantly decreased. The tingling she was experiencing over her left buttock is “shrinking” in the sense that it is less intense and is distributed over a smaller surface area of her buttock. She is also finding her movements through the lumbar spine to be easier… previously she could reproduce her pain with movement quite easily, now she reports that she has to move nearer to the end range of her normal movement in order for her to feel the pain in her left leg.
These are all great signs that suggest to me that the irritation around her S1 nerve root is settling down. The rapid improvements help to reinforce the idea that even though she was in severe pain for a few days, her initial injury was more likely only mild (in terms of severity of damage to tissues). Severe symptoms are unlikely to resolve quickly if they have arisen from significant damage to a structure in the spine. In Sophie’s case, I suspect she has some degenerative changes at her L5/S1 disc, and that her initial symptoms were triggered by a rapid ramping up nerve ending sensitivity subsequent to a mechanical irritation of the disc.
I expect her symptoms to continue to diminish over the upcoming weeks. The challenge for Sophie for the next few weeks will be avoiding flare up of symptoms. It will be important for her to get back to her usual daily activities and exercise outline gradually.
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