neurosurg

The spread of opinion on trauma in degenerative disease of the spine

Tiernan J.Byrnes and Fred P. Nath

Introduction

The introduction of the Woolf Reforms (1) has brought about significant alterations in the way that medical experts produce reports. The constant requirement to communicate and record differences of opinion or agreement has meant that experts are far more aware of each other’s views in relation to their experience and the basis upon which they formulate opinions. This is nowhere more true than in the field of spinal injury. The commonly held view that injury in the spine leads to the ‘activation’ of previously silent degenerative or wear and tear changes is often quoted and from the author’s experience of joint reporting, appears to be held by most experts.

The purpose of this study was to examine whether such views are indeed conventional wisdom shared by all, or whether a minority only holds this view. Establishment of data on spread of opinion is of value to medico-legal experts and the court in substantiating the likely accuracy of statements made in their reports.

Methods

Forty experts were selected at random from the UK register of Expert Witnesses. These experts consisted of Orthopaedic surgeons, Accident and Emergency surgeons, Neurologists and Neurosurgeons. Communication was by e-mail, post or verbal communication (Fig 1).

There were 25 replies. Only five of these replied without qualification of their answers although one of the questions in retrospect may have been ambiguous (question 2). The five questions are set out in Table 1.

The results were tabulated using Microsoft Excel.

Results

Question 1

In which decade does degenerative disease of the spine become spontaneously symptomatic?

The spread of opinion was from 3rd decade (20s) to 7th decade (80s) (Fig 2). The majority of experts however felt that spontaneous symptoms arise in the 4th (24%) or 5th (56%) decades of life (fig 1).

Question 2

Does spinal trauma accelerate the rate of degenerative disease?

This question was ambiguous and the replies required interpretation. The majority of experts qualified their answers by statements such as “only in the presence of fracture” or “if there is damage to a joint surface”. Taking this into account 64% of the responses were that injury can (under some circumstances) increase the rate of degenerative disease (Fig 3).

Question 3

Does trauma accelerate the appearance of symptoms from degenerative disease of the spine?

92% of the experts agreed that symptoms may be accelerated in their appearance by trauma (Fig 4). It is therefore quite clear that although the degenerative process is not universally accepted as having been accelerated by trauma, the acceleration of the appearance of symptoms by trauma is a much more commonly held hypothesis.

Question 4

Can soft tissue injury in the spine give rise to symptoms for more than 2 years?

68% felt that it could (Fig 5). It therefore seems to be accepted by the majority of experts that symptoms from soft tissue injury can give symptoms for more than two years and this is confirmed by the replies to the final question.

Question 5

One surgeon failed to answer this question, there were therefore 24 replies.

What is the maximum time that a soft tissue injury can give symptoms?

63% said indefinitely (Fig 6). The remainder indicated one or two years.

There is therefore a measure of agreement that soft tissue injuries can give rise to long term symptoms although this study gives no indication of any possible mechanism by which this may occur.

Discussion

It will be accepted that a group of independent experts asked the same questions are unlikely to give the same answers and it needs to considered at what level of agreement one can say that a statement is conventional wisdom. Experts often quote the axiom “conventional wisdom”, but there remains no strict definition of how conventional the statement has to be to be accepted. This study attempts to outline the spread of opinion in the specific scenario of spinal degenerative disease and trauma. Although the data allows one to state on balance of probability that the majority of experts hold a particular view there still remains a body of opinion with a contrary view in each of the questions put in this study.

The only point, which was very well accepted, was that symptoms from degenerative disease might be accelerated in their appearance by trauma. This mechanism for the failure of symptoms to settle after an injury is commonly used to explain why patients remain symptomatic even in the absence of severe injury or fractures. This therefore seems, from these results to be truly conventional wisdom.

It is not surprising that the majority of experts in this study felt that degenerative disease becomes spontaneously symptomatic in the 4th or 5th decades of life, as this is common experience and demonstrated in the majority of studies that have looked at investigation or surgical treatment for degenerative disease in the spine (2)(3)(4)(5). The combination of the first and third questions may have relevance in deciding how much a patient’s condition has been accelerated by an injury, as the closer the injury occurs to the end of the 4th decade the greater the likelihood that symptoms would have become spontaneously symptomatic. This must of course be viewed with some reservations as in individual patients previous history and life-style and occupational factors also have to be taken into account.

Persisting symptoms after soft tissue injuries to the spine are well documented (6), particularly in the neck and it is well known that whiplash injuries may give symptoms indefinitely. This appears from the data in this study, to be broadly accepted, but with a dissenting minority of 36%.

Those who do not agree may have been influenced by studies which have revealed that persistence of symptoms does not occur in countries in which litigation is not possible (7) indicating that the long term sufferers may be influenced by more factors than the pathology itself.

Opinion appears to be divided as to whether the rate of degenerative disease may be influenced by injury. The probable explanation is that there exist no definitive longitudinal studies on the progression of degenerative disease in the community at large. That severe trauma with structural alterations to the joint surfaces and alignment of the spine leads to early degenerative change is commonly accepted. This explains why such a high number of the responders agreed with question 2. The data on this question however is flawed, as some experts may well have been referring to minor injuries such as back strain or whiplash injury.

This study therefore does not answer whether experts believe that degenerative change as a pathological process is influenced by trauma.

Conclusion

The majority of medico-legal experts canvassed in this study accept that symptoms of degenerative disease of the spine are accelerated by injury and that the time of onset of spontaneous symptoms from degenerative disease of the spine is between the 4th and 5th decades of life. It would be unwise however to attach too much significance to these data as the sample was small and degenerative disease in the spine is influenced by many factors which were not taken account of in the present study. The results do however represent the spread of opinion in a randomly selected group of medical experts.


References

1. Woolf. Access to justice: Final report 1996

2. Porchet F, Weitlsbach V, Burnand B, Daeppen K, Villemure J, Vader J: Relationship between Severity of Lumbar Disc Disease and Disability Scores in Sciatica Patients. Neurosurgery, Vol. 50 No. 6, June 2002

3. Park Y, Kim J, Oh JI, Kwon TH, Chung H, Lee K: Facet Fusion in the Lumbo-Sacral Spine: A 2-Year Follow-up Study. Neurosurgery, Vol. 51. Number 1. July 2002

4. Beatty RA. Surgery for patients with central protruded lumbar discs who have failed conservative therapy: British Journal of Neurosurgery 1996;10(4):373-377

5. Donaldson JW,Nelson PB. Anterior Cervical Discectomy without Fusion: Surg Neurol 2002 Apr;57(4):219-24

6. Khan S, Bannister G, Gargan M, Asopa V, Edwards A. Prognosis following a second whiplash injury: Injury. Vol 31(4) (pp 249-251), 2000

7. Schrader H, Obeliene D, Bovim G, Surkiene D, Mickeviciene D, Miseviciene I, Sand T: Natural evolution of late whiplash syndrome outside the medicolegal context. Lancet. 347(9010):1207-11, 1996 May 4.



Figure 1. Questionaire (full list of questions)
1. On balance of probability, in which decade does spinal degenerative disease become spontaneously symptomatic?
2. Does spinal trauma increase the rate of degenerative change?
3. Does Trauma accelerate the appearance of symptoms from degenerarive disease in the spine?
4. Can a soft tissue injury in the spine give rise to symptoms for more than 2 years?
5. What is the maximum time that a soft tissue injury can give symptoms for?

Figure 2. Graph of expert opinion of timing of spontaneous onset of symptomatic spinal degenerative disease.

Figure 3. Percentage of experts who felt that the rate of degenerative disease is increased by trauma.

Figure 4. Percentage of experts who believe trauma accelerates the appearance of symptoms from Degenerative Disease.

Figure 5. Percentage of experts who feel that soft tissue injury can give rise to symptoms longer than two years.

Figure 6: The majority of experts feel that soft tissue injuries can give rise to symptoms indefinitely.