neurosurg

Litigant's backache

Backache is the easiest symptom to feign and the most difficult to confirm. This is partly because even when due to injury the symptoms may vary in timing and severity.

Soft tissue injury leads to acute initial symptoms and a longer drawn out period of discomfort of lesser degree and during the latter phase little is found when examining such patients. The difficulty is that the burden of proof lies with the claimant and the patients word is simply not enough on which to base legal proceedings.

Degenerative disease of the spine leads to symptoms that continue for longer than two years from injury but the symptoms vary from day to day and from month to month so there is frequently a disparity between the examination findings in these cases. This is not uncommon and generally accepted by the courts. The commonly quoted phrase “good days and bad days” is in fact quite accurate in addition to which activity frequently leads to inflammatory pain occurring some days layer (although usually the following day) and the relationship to the specific activity that has led to the symptoms may at first glance either not be recognized or not believed.

Accurate scientific assessment of the patient with back pain is therefore, fraught with difficulties as the assessment may be carried out on a “good” day and does not lead to provocation for a day or two.

Medical examination therefore depends upon a single snapshot taken at the time of the examination. No film critic would be expected to write about a film basing his opinion upon a single still picture taken in the middle of the movie. There are therefore inherent difficulties in such short term assessments. There are however, ways of assessing the real and apparent symptoms in individual patients which can give the specialist an edge and this is what this article is about.

The water is further muddied by the fact that patients often exhibit a exaggerated response to their injury in compensation cases and this introduces difficulty in assessing the severity of symptoms. This excessive reaction to symptoms is termed functional overlay. Functional overlay however is not the exclusive province of claimants in medico-legal cases. It is well recognised that it occurs in the wider context of general clinical work on the basis that all illnesses have both a physical and a psychological component. The relative proportion of each of these components varies with the patient and the symptoms and the circumstances of the injury.

True malingering is a rarity in the author’s practice , but one can be caught badly if all information about the client is not available at the time of compiling the report. This includes video evidence. Video evidence is not usually of great significance as the symptoms vary from day to day and it is natural for someone with pain to attempt a variety of activities which lead to symptoms occurring next day or which are not possible on a bad day. There are exceptions to this and these can be detected by the magnitude of the disparity.

A 46 year old roofer fell 4 meters onto his buttocks sustaining a flexion injury of the lumbar spine. He was seen at 18 months after injury for a report and claimed to be in severe pain and unable to work. Examination supported the likelihood that he had symptomatic lumbar degenerative disease accelerated in it’s appearance by the injury.

The case came to court and on the morning of the trial the expert was confronted by a video of the claimant climbing a roof and engaging in activities which can only be described as demonstrating a completely normal back. He was seen to enter a house and then climb a ladder and actively carry materials and do roofing work. In evidence, the claimant suggested that it was not him but his brother-in-law on the roof as they had exchanged jackets inside the house. The judge enquired whether they had also exchanged trousers? Confronted by such evidence the expert could only concede that if the symptoms to be genuine it could not be the claimant on the roof. The case was lost.

This highlights that not only must one have all the evidence to hand but that any expert can be fooled by a client who is not honest.

Functional Overlay

This term is in frequent use by medical experts when describing claimants when there is a disparity between the patients claimed symptoms and one’s examination.

It is not meant to imply purposeful simulation. When there is malingering (as opposed to functional overlay) it is usually obvious to the examining doctor as the physical signs are at such marked variance with known pathology that it is obvious that the patient does not suffer the alleged back pain. If a clinician feels that there is malingering he must express this in those specific terms in his report and failure to do so can only be interpreted as misleading the court.

A medico-legal client was referred to the author with a history of a lifting injury at work some two years after the event. He entered the consulting room using two sticks for support, wearing dark glasses and shuffling very slowly. When examined even the slightest back movement caused him to cry out with apparent agony. There were no neurological signs and obvious disparity between certain movements and the severity of his pain.

After examining him, the author followed the patient at a safe distance to see whether the symptoms continued after consultation. Although at interview he claimed that he could only walk twenty yards he was seen to walk back to his car 100 yards away. He dropped one of his sticks and bent over to pick it up and then placed it in the other hand carrying both sticks and no longer using either for support. The report reflected all these disparities and the case folded.

The point is, that although there were multiple signs of functional overlay on examination, the intention to deceive is not clear without some further evidence, not necessarily medical.

Gordon Wadell, an orthopaedic surgeon in Glasgow described physical signs on examination which may indicate functional overlay although the original paper referred to “illness related behaviour”. The described signs include:

1. Superficial tenderness
Gently pinching or just touching the skin of the back elicits audible complaints of discomfort. The skin of the back is never tender to touch after a back injury and one can therefore conclude that the physical sign itself is spurious.

2. A disparity between straight leg raising and sitting with the leg outstretched
The straight leg raising test is intended to put the nerve root in the spine under tension . This is rather like a bowstring where stretching the nerve across a prolapsed or bulging disc produces pain and thereby limits the number of degrees from the horizontal that the leg can be elevated. If the knee is bent it reduces the tension in the affected nerve and the pain goes. A patient exhibiting functional overlay may only allow 30-40 degrees of straight leg raising (and usually they complain of back pain). If the patient is then asked to sit with the legs out straight in front of them or asked to straighten the knee when sitting, they can do so without apparent discomfort. In a patient with a prolapsed disc or other condition leading to tension in the nerve root the straight leg raising is only possible to the same degree that they are able to have the leg out straight before them. There is a caveat in this however. I have seen patients with severe disc prolapses which occur centrally in the spinal canal and cause pressure on the more central nerves but the two nerves that exit the spine at the side of the disc space escape. Such a patient may have quite good straight leg raising but still harbour significant pathology.

Back pain with straight leg raising however, is not a sign of disc prolapse and eliciting this symptom is not the purpose of the straight leg raising test which is intended solely to examine whether the patient has nerve root tension which gives pain felt in the distribution of the nerve i.e. down the leg. A disc prolapse in the upper lumbar region may (to confuse the issue) produce pain on extending the leg (pulling the leg backwards) as this stretches the femoral nerve as opposed to the sciatic nerve involved by the lower two discs.

3. Vertical pressure producing pain
Pressing on the patients head or shoulders in a vertical direction never causes pain in true spinal pathology. The spine is at it’s most stable in the upright position and the weight is distributed so diffusely that even in severe disc prolapse it does not cause pain. One can contrast this to the patient who, when one presses on the shoulders, groans with pain and the knees buckle. Such patients are deemed to have functional overlay.

4. False rotation
The facet joints in the lumbar spine are positioned in such a way that when the lower spine is extended (straight) as in the normal standing position, no rotation takes place. In a patient with pathology in the lower lumbar spine rotating the shoulders with the hips kept still, causes no movement in the lumbar spine and cannot cause significant pain. There is however a caveat even in this, in that the rotation may pull slightly on muscles below or on inflamed soft tissue and this could potentially cause some discomfort although such discomfort is clearly not from the lumbar disc or joints and ligaments.

5. Hip movement causing pain
A patient lying down with the hip and knee bent is in a position whereby the nerve roots are relaxed. Rotating the hip in this position cannot cause nerve root or back pain. If rotation of the hips causes such pain there is clear evidence either of pathology in the hip (in which case the pain is localized to the hip but can radiate to the groin or towards but not below the knee) or there is functional overlay

6. Voluntary reduction in power
When testing the lower limbs for neurological signs one examines the strength of specific movements. If a movement such as knee flexion (bending) appears weak varying the force that one exerts against it’s movement makes no difference to the degree of weakness. It is a characteristic of functional overlay that the patient is able to move the limb but all effort ceases as soon as it is tested. With experience an medical expert can easily tell if the claimed weakness is voluntary or real. Neurological weakness in the lower limb, if due to nerve root embarrassment is also usually accompanied by some muscle wasting and almost always by sensory loss of a distribution appropriate to the nerve root affected.

An exception however is when the limb movement caused pain in the back and this pain reduces the effort in the patient moving the limb. This is however not an nerve root phenomenon.

7. Non-anatomical sensory loss
When a nerve is compressed or damaged numbness occurs in the specific distribution of the nerve and the pattern of numbness follows a specific anatomical distribution which is well recognized by the examining doctor. The numbness does not appear in a stocking or glove distribution. The patient who exhibits functional overlay may not only have numbness in a stocking distribution but often has numbness over a much wider area than can be possible from the known injury.

An example is a patient with sciatic pain and numbness from the groin down to include the entire leg. To have pathology to account for such extensive sensory loss there would have to be a significant spinal cord lesion above the first lumbar vertebra ( they are numbered 1-5 from above down).

Peripheral neuropathy e.g. due to diabetes or heavy metal poisoning may produce a stocking loss of sensation so the presence of this pattern of numbness is not always factitious.

8. Audible moaning and groaning
It is unusual unless one does something really violent to a patient on examination, to hear them cry out audibly with pain, except in very acute infection or very recent trauma. This is usually associated with functional overlay but is only of value as part of the overall picture.

The Nature of Functional Overlay

If some or all of these signs of illness related behaviour are elicited on examination one needs to consider the significance when constructing a report. On the one hand it may be part of a complex psychological reaction such as a post-traumatic stress disorder or it might be a patient who has pain but wishes subconsciously to convince the examiner of the severity of the symptoms. The latter leads to an exaggeration of the perception of the pain and makes the symptoms perceived by the patient seem greater than they might under other circumstances. It is not that they do not have pain, rather that they perceive their symptoms to be worse than they truly are.

An unfortunate consequence of this is that the actual severity of the symptoms becomes unquantifiable. When reporting on such patients one must consider that the case itself depends very much upon whether there is a relationship between the observed disability and the relevant accident. A simplistic view might be that if there was no relevant accident there would be no post-traumatic psychological reaction. This however is rather more a judicial than a medical matter.

A 45 year old lady had a whiplash type of injury and one year later was examined for a medico-legal report. The examining doctor found that there was a convincing history and on examining the patient there were neurological signs suggestive of nerve root compression in the neck. An MRI scan was financed by the defendants and this revealed a significant disc prolapse which was causing both nerve root and spinal cord compression. The defendants paid for the lady to have private surgery to remove the disc. At operation a huge disc prolapse was removed and it was obvious to the surgeon that severe spinal cord and nerve root compression had been relieved.

Six months later on review the patient claimed she was considerably worse with more pain and weakness in the arm. The surgeon doing the report described the surgery as unsuccessful but found it hard to marry up the operative findings with the subsequent result. Was this functional, malingering, or a genuine poor result from surgery? The lady did however have spurious signs in that there was apparent voluntary weakness in the limb, non-anatomical sensory loss extending to the neck and head and vertical pressure on the head appeared to produce neck pain which led the examining expert to conclude that this was an unconscious reaction. Who knows in reality how severe any residual symptoms are in a case of this sort?

Conclusion

Although illness related behaviour may occur in claimants there are means by which the expert can detect this. Having decided that there is a likelihood of functional overlay however, it is a moot point whether this is purposeful or unconscious. Most experts would agree that the above signs of functional overlay need to be definite and multiple before one can conclude that the overall picture is of a functional nature. In addition there are some caveats in the diagnosis which require experience in the interpretation of the spurious physical signs.