In medico-legal practice, the question of whether or not a specific injury or repetitive work practice caused or contributed to an individual’s back pain or disc prolapse is very commonly raised by instructing parties. Orthopaedic and spinal surgeons have a variety of positions open to them because, as we are all aware, there is almost always a range of opinion on the subject of causation in these cases. That range usually extends from nil/minimal causation through to total causation. There is often consternation among the legal profession that “expert” opinions can vary so much.
The further opinion on causation often given in these cases is the rather nebulous concept of advancement/acceleration of symptoms caused by the incident/s in question. Is this a cop out or does it have some merit? Professor Michael Adams, one of the world’s leading experts on spinal biomechanics, believes that the advancement/acceleration concept “is not quite compatible with the disease process outlined above.” However, he gives some support by describing how mechanical loading may divert the disc from its normal ageing pathway to a separate degeneration pathway.
The fundamental question remains whether in the asymptomatic but degenerate spine this diversion would have occurred anyway through the “normal” stresses and strains encountered during the activities of daily living in the home, workplace or recreational environment. Professor Adams advises that liability should be apportioned according to the perceived relative importance of predisposing and precipitating factors.
How do we integrate this into a practical and workable approach to the assessment of the merits of a claimant’s case? It is clear that the mechanism of injury to the disc/spine is of fundamental importance. Common sense dictates that there must be a temporal relationship between the injury and the onset of symptoms. It is useful to have corroboratory medical evidence of the injury and early symptoms. A past medical history of similar problems will give an idea of the degree of vulnerability that existed in the spine.
Hopefully, armed with extensive clinical experience, an understanding of the epidemiology and pathophysiology of back pain, disc degeneration and disc prolapse, and the science provided by Professor Adams, we will be in a better position to opine on these difficult and controversial issues.
