(c) In my opinion, your client's present back symptoms are due to an ongoing aggravation of a pre-existing and only partially symptomatic degenerative condition.
… "
25 The judge referred to what other doctors had said about the cause of the appellant's injury, but in the appeal the submissions focussed on the opinions of the four doctors I have mentioned. The judge said that she did not accept Dr Bentivoglio's "opinion as to frank injury" because of "the errors in its basis". She said, immediately preceding her finding set out above -
"I do accept his Dr Lorentz' opinion that a frank injury was a possibility. However, I find that it is a possibility that is negated by the overwhelming weight of medical opinion. In that respect, I note that material made available to Dr Lorentz included various medical reports and the results of the CT and MRI scans, but not the x-rays or x-ray reports. That is of some significance in the circumstances where:
· There is concurrence that that which is visible upon x-ray is significant (relevantly excluding recency);
· Dr Bentivoglio relevantly misread the February 2001 x-ray to see no evidence of damage at L4/5; and
· The reports by Dr Matheson, Dr Basser and Dr Bodel were not specific as to that which was observable upon the February 2001 x-ray (as distinct from CT scan), and thus did not correct the error in Dr Bentivoglio's report in his implication that there was no damage visible on the x-ray at L4/5.
It seems that Dr Lorentz' opinion and report was thus relevantly infected by Dr Bentivoglio's misreading of the x-rays, although I note that relevantly Dr Bentivoglio's opinion is expressly to the contrary of Dr Lorentz' in respect of the injury at L5/S1.
I have preferred the opinion of Dr Evans and Dr Matheson to that of Dr Lorentz."
26 Dr Bentivoglio provided a report dated 29 May 2003. He said that the appellant "would have aggravated pre-existing degenerative changes present [to] his back region and made them symptomatic as a result of the position he had to adopt at work", and that two-fifths of his current disability would be as a result of pre-existing degenerative changes present in his back region and three-fifths would be "as a result of the injury to his back caused by the position he had to adopt at work". This did not attribute particular significance to the appellant's movement on 18 January 2001.
27 In his oral evidence in chief Dr Bentivoglio said that the movement "could cause discal damage easily", and that disc lesion found by Dr Basser at the L4/5 and L5/S1 levels from the CT scan was capable of causing back pain and a complaint of sudden and severe back pain was suggestive of a disc lesion. He did not more specifically opine that there had been a particular injury on 18 January 2001.
28 In a fairly lengthy cross-examination Dr Bentivoglio agreed that the degenerative changes visible on the scans indicated degenerative changes existing prior to January 2001, with some doubt as to the L4/5 level, and he agreed that the posture the appellant was required to adopt could cause the degenerative change but depending on a history of more than occasional bouts of pain. He said that he could not tell from the radiology exactly when the L4/5 level change occurred.
29 Only in re-examination did Dr Bentivoglio say that the three-fifths to which he had referred in his report "would be as a result of that - the incident on, you know, arising from the day". There was further cross-examination, in which he agreed that without before and after radiology he could not say "what injury was caused by what or what actually happened on that day specifically", and -
"Q. And you can have over a period of time a gradual build-up of degeneration eventually leading to some form of lesion?
A. Yes.
Q. And it is possible that although that degeneration is continuing to occur the person might not be aware of the continuing degeneration happening until it reaches a certain point?
A. Yes, that can be the case.
Q. And it could be that the pain that he feels can be excruciating but only result in a very minor change in the degenerative condition.
A. Yes."
30 In further re-examination, he said that the finding of disc damage shown at the L4/5 level in the CT scan of 28 February 2001 was "more likely to be a frank injury rather than a degenerative disc".
31 The judge was somewhat critical of Dr Bentivoglio's evidence so far as he said that the plain x-rays did not indicate damage at the L4/5 level, and preferred the opinions of the other doctors in that respect. She was entitled to prefer them. She said that Dr Bentivolgio's opinion "relevantly relied upon error in his observation of the x-rays", it seems meaning his opinion that the disc damage shown in the CT scan was more consistent with a frank injury than with degeneration. The appellant submitted that it was not correct that Dr Bentivoglio's opinion was undermined by any misreading of the x-rays, because his opinion rested upon the CT scan not the x-rays. I do not agree. The judge was entitled to conclude that an opinion as to the origin of the damage as shown in the CT scan was influenced by the view that the x-ray did not show pre-existing degenerative change at the L4/5 level. I see no error in her Honour declining to accept Dr Bentivoglio's opinion as to frank injury, which was in any event rather qualified on his evidence as a whole.
32 Dr Lorentz recorded a history of developing "very severe, sudden pain" when the appellant was "looking to the left, looking at one of the trucks arriving and in the process he twisted his back". I have earlier set out his opinion from his report of 7 October 2004. He did not explain in the report why he thought there had been a super-added injury suffered on 17 January 2001.
33 Dr Lorentz did not add to his report in oral evidence in chief. In cross-examination he agreed that constant flexing of the appellant's back as he operated the gantry would create trauma, with "small elements and additive elements of trauma over a period of time" contributing to the degenerative changes in the appellant's back, and that as the degeneration advanced it could eventually get to the point where it caused pain. He said that this did not exclude "acute disorder occurring", meaning "for instance a disc protrusion or disc rupture which could be responsible for the pain", although he also agreed that the disc protrusion or disc rupture could be "part of the degenerative process". There was evidence not fully recorded because of transcription difficulties, as I read it amounting to him agreeing that the disc protrusion to which he referred in his report could have been caused by degeneration, but that it "suggested some forces occurred which caused the part to rupture of the disc which is not degenerative but caused by trauma [sic]"; the trauma was more likely to be something more acute than continuous forward flexation although it did not have to be a "major traumatic event".
34 As I have indicated, the judge considered that Dr Lorentz's opinion that a frank injury was a possibility was "negated by the overwhelming weight of medical opinion", and referred to infection of his opinion by Dr Bentivoglio's misreading of the x-rays. The appellant submitted that it was irrational to regard Dr Lorentz's opinion as infected by Dr Bentivoglio's misreading of the x-rays.
35 Dr Bentivoglio's report of 29 May 2003 was provided to Dr Lorentz, together with the reports of Drs Matheson, Basser and Bodel, and it is plain enough that the judge was referring to the information made available to Dr Lorentz through these reports. In his report Dr Bentivoglio said that the plain x-rays showed a marked decrease in the L5/S1 disc space but, conformably with his reading of them earlier mentioned, said nothing about them showing a narrowing at the L4/5 level. Although Dr Lorentz did not refer in his report to the plain x-rays, saying only that he had seen the CT and MRI scans and agreed with the reported findings, the reports provided to him must have been taken into account in forming his opinion. The report of Dr Bentivoglio conveyed what the judge described as an implication, not corrected in the reports of Drs Matheson, Basser and Bodel, that there was no damage visible on x-ray at the L4/5 level, and while the influence may not have been large I do not think the judge's reasoning was not open.
36 Dr Matheson provided a report dated 17 February 2004. He said that the appellant had "degenerative disc disease at L4/5 and L5/S1 associated with facet joint degeneration", and that it was "not a work related condition" but a "constitutional condition". He said that "[t]he event on 17 January 2001 was not an injury as such. It was just that the pain got quite bad and he got out of the crane and could not continue working". The continuing symptoms were "due to his underlying degenerative spinal condition".
37 In his oral evidence in chief Dr Matheson said that the degeneration evident from the x-rays and scans had progressed over at least two years, that they could be symptomatic, and that they had been symptomatic since early 2000 but could have gradually increased consistently with his findings. He said that the movement as described by the appellant was "not activity that would influence the lumbar spine at all".
38 In cross-examination Dr Matheson did not change his views on the assumption of an episode of extreme or excruciating low back pain on 18 January 2001, saying in effect that it was just a progression from no back pain to mild back pain to severe back pain. He agreed that a downward and twisting movement could cause pain and possibly herniation of a "fragile disc", but attributed the appellant's pain to existing disc lesions rather than disc lesions caused by his moving forward quickly in a twisted position. His evidence included -
"Her Honour: Q. Why is it the disc lesions cause pain this time but not 20 minutes earlier?
A. Your Honour I have no way of answering that question. But the reality of the situation is that the pattern of pain that emerges with people with spondylitic conditions of the spine is episodic, unpredictable and sometimes is relieved by heavy work and sometimes brought on by heavy work. It's an arthritic condition essentially and if you just get those joints into a right position to produce some pain an episode of pain sets in
…
Q. Well we know that there are disc lesions at L45 and L5S1?
A. Yes.
Q. And you've said that those lesions are capable of producing pain?
A. Yes.
Q. Assuming that those lesions were not present at the commencement of his shift because he wasn't in pain?
A. But they were present at the commencement of his shift.
HER HONOUR: Q. How do you know that?
A. Because your Honour it's a chronic degenerative condition with arthritic changes in the facet joints, signal loss with the discs, this is a process that's been present for some considerable time.
STERNBERG: Q. But assuming that they were completely asymptomatic?
A. Assuming they were completely asymptomatic, yes.
Q. Why isn't a sudden forward movement in a forward flex position capable of causing discal damage?
A. It's not going to cause discal damage in a normal disc. If you've got an abnormal disc it arguably could be made worse, but we would need to demonstrate some radiological features of that."
39 In the context of the experiencing of sudden severe pain, it was specifically put to Dr Matheson -
"Q. Isn't that the case here that there was some further damage to a structure of the body, namely his low back as a result of what he experienced on 17 January?
A. No most episodes of back pain will be associated with some inflammation and swelling which is self limiting and goes away and leaves them no worse for that one episode than they were before but at the same time, this is a progressive matter over a period of years."
40 Dr Evans provided a report dated 14 November 2001. He recorded a history that between 1999 and January 2001 there was a gradual worsening of the pain, and that in January 2001 "the back pain had become very troublesome". He gave as his opinion -
"DIAGNOSIS: In 1999 Mr Khaya noted the gradual onset of pain in his low back. It would occur when he was bending and lifting at work. It gradually worsened, and caused him to see his local doctor first in January 2001. He spent a period off work, returning to light duties, and, at least partly because of this, was sacked, in July 2001. He continues to experience pain in the back, fortunately not radiating to the legs.
The back pain doubtless arises from the damaged, degenerate, L4/5 and L5/S1 discs. He thus experiences pain and stiffness in the low back.
The stresses to which his back has been exposed would be unlikely to cause disc damage of this sort in completely normal intervertebral discs. It is thus likely that there is a component of constitutional degeneration, making the discs a bit weaker than average."
41 Dr Evans did not materially add to his report in his oral evidence in chief. In cross-examination he said that a "quick forward flex movement and some twisting at the same time" could cause discal damage in a degenerate disc, although not a healthy disc, and -
"Q. And if the pain is sharp and sudden and quite severe immediately following that forward flexation movement, is that something that might be pointing to damage having been sustained to a disc or more than one disc?
A. It's consistent with it but not diagnostic of it. I think the correct way to look at this is as a segment at the back so it could be disc damage or it could be facet joint damage at the same level which is a much milder thing. So it's not actually specifically."
42 Asked to assume episodes of back pain and then intense pain in January 2001, Dr Evans regarded it as a history of gradual worsening of back pain, as opposed to discrete injuries, albeit that the last increment in pain was more significant.
43 In re-examination, Dr Evans spoke of trauma to the spine occurring to a minor extent every time a person flexed forward, and said that a degenerative spine which was symptomatic and worsening would not get worse at exactly the same rate and that there could be increases in pain greater than earlier increases.
44 In Dr Ganora's report he gave the opinion that the appellant had "sustained a lumbo-sacral injury in association with his work activities in January 2001". Dr Khan referred to aggravation of a degenerative back condition as a result of the general nature and conditions of employment "including the work incident of 17.1.01". Dr Garvey related the appellant's condition to his employment as a stevedore operating the gantry. Dr Bodel referred to disc pathology at L4/5 and L5/S1 arising "as a result of the nature and conditions of [the appellant's] work as an RTG driver … ", and said that the appellant "gives no history of any other accident or injury which could have caused his pathology seen on the MRI scan". Dr Hession, who recorded a history of exceptionally severe pain as at 19 January 2001 but not of the movement on 18 January 2001, diagnosed degenerative lumbar spondylosis "likely to have been aggravated by the nature and conditions with his employment … ". None of these doctors were more specific as to injury at a particular time. Some of the opinions were of uncertain value because it is not clear that account was taken of sudden severe pain in the specific movement on 18 January 2001.
45 There could be no certainty in finding what happened to the appellant's back, if anything, on 18 January 2001. There was degenerative change, constitutional or the result of past incremental trauma from the flexation of the appellant's back as he had driven the gantry. The acute pain on 18 January 2001 may have been an increase in the progression of pain without any change in the condition of his back, because he got his joints in the right position to produce pain (in the language of Dr Matheson) or with an incremental advance in the progressive condition which would not qualify as an injury. Or it may have been what the judge referred to as a frank injury, on the appellant's submission disc lesions or herniations occurring at that time.
46 The medical opinions differed, but there was a sound basis for coming to the conclusion that there had not been a frank injury. At least in part her Honour's conclusion was likely to have involved the impression made upon her by the doctors she saw and heard: as was said in Wiki v Atlantis Relocations (NSW) Pty Ltd (2004) 60 NSWLR 127 at [60], "A judge may be persuaded by a combination of the material force of an expert's views together with the way in which the evidence was given". She did not, of course, purport to come to her conclusion solely on the basis of impression, but engaged in examination and analysis of the evidence.
47 The judge stated it highly when she referred to an overwhelming weight of medical opinion against the possibility of a frank injury, and the influence upon the opinions of Dr Bentivoglio and (derivatively) Dr Lorentz of what was not seen in the plain x-rays may not have been large. I do not think her Honour regarded it as determinative, and as part of the analysis it was material. The appellant submitted that the acute pain of 18 January 2001 was self-evidently more than an escalation of periodic pain from the degenerative condition, and all but compelled the conclusion that a marked physiological change had occurred. But that was not accepted by (for example) Dr Matheson, and I am not persuaded that the judge was in error in her finding that there was not a frank injury; or as I would prefer to put it, that an injury did not occur at the time of the appellant's movement on 18 January 2001.