Resolution of conflicting medical opinions
72The conflicting expert medical opinions in evidence in this case have to be reconciled as they cannot stand together. This task presents difficulties for analysis where the parties ultimately determined, despite earlier indications to the contrary, that they would not call explanatory oral evidence from the medical experts whose reports were tendered. Notwithstanding, such difficulties, I am required to engage in this task as best I can with the available materials that the parties have tendered.
73The task, which leads to the preference of one body of opinion to the other, involves an examination of the reasoning process of the experts whose reports are tendered: Dasreef Pty Ltd v Hawchar [2011] HCA 21, (2011) 243 CLR 588, at [92]; K & M Prodanovski Pty Ltd v Calliden Insurance Ltd [2012] NSWCA 117, per Meagher JA at [25].
74In embarking upon this analysis, it is useful to identify the plaintiff's pre-injury baseline condition, which comes from the evidence of the plaintiff and his wife, and from the other tendered medical evidence.
75In this regard, there was nothing within the evidence of either the plaintiff or his wife to indicate that he knew that he had been harbouring a debilitating or work limiting condition of his spine. Neither the plaintiff's work history, the description of his pre-injury domestic activities, nor the evidence of Mrs Humphries, pointed to an awareness of the presence of any underlying problem with his back that might have an adverse impact upon his ability to carry out heavy work, or work requiring strength, mobility and physical dexterity.
76Due to the plaintiff's pre-injury personality, his pre-injury pattern of medical attendances had been sporadic. This may very well have been due, using his own self-effacing words, to his disposition that he "was not a fan of doctors" or because he had very few problems of concern to him. In considering the significance of that evidence, it seems to me that the meaning the plaintiff was seeking to convey was that generally, he was not a person prone to seeking out medical attention for minor ailments or injuries which would obviously heal themselves if nature was left to take its course.
77That said, there were some documented instances of medical attendances by the plaintiff between 2003 and 2008, including referrals for x-ray examinations. None of the notes of the general practitioner consultations relating to those referrals made reference to any pathology of the plaintiff's thoracic spine. One of those earlier radiology reports from those x-ray examinations were tendered in evidence in these proceedings.
78Having accepted that the plaintiff's evidence that he was pain free and disability free in his thoracic spine immediately before the February 2008 incident, where his evidence in that regard was not contradicted by other evidence, and where his evidence on this subject was not otherwise improbable, it is necessary to review the medical opinions in the light of that finding.
79Against that background, it is necessary to identify the polarised opinions within the expert medical opinions. There is a body of expert orthopaedic opinion comprising the reports of Dr Searle and Dr Billett, which relate the plaintiff's current problems to the work incident on 22 February 2008. Against that body of evidence is the expert orthopaedic opinion of Dr Silva, to the contrary. These competing analyses need to be weighed. The following paragraphs summarise and analyse those opinions in the order in which they have evolved.
Dr Searle
80Dr Searle's report of 4 December 2010 reviewed x-rays and MRI scans of the plaintiff's spine. Dr Searle made no mention of a diagnosis of Scheuermann's disorder, but referred to pre-existing spondylosis of the thoracic spine, which in his opinion, was aggravated by the incident of 22 February 2008, and that such aggravation was persisting, permanent in its effect, and which continued to cause the plaintiff a moderately severe degree of disability. This opinion serves to explain the plaintiff's ongoing symptoms.
Dr Silva
81On 27 May 2011 Dr Silva carried out his orthopaedic assessment of the plaintiff. The essence of his 1 June 2011 opinion provided to the solicitor for the defendant was that the x-ray and MRI scans of the plaintiff's thoracic spine revealed evidence of pre-existing classical Scheuermann's disorder of the mid-thoracic vertebra.
82Dr Silva was of the opinion that the incident of 22 February 2008 probably aggravated that condition. He went on to express the opinion that the effects of the aggravation had since resolved, leaving the plaintiff with a good prognosis. Dr Silva's opinion, which was given 3 years following the plaintiff's injury, did not indicate the actual or likely timing of such resolution. Unlike Dr Searle's report, this report does not explain the rationale for the plaintiff's ongoing symptoms.
83The solicitor for the defendant sought clarification of Dr Silva's opinion. Dr Silva's 3 May 2012 letter of response to the solicitor for the defendant addressed a series of 8 questions that were raised with him by the defendant's solicitor. None of those questions raised the likely timing of the resolution of the aggravation of Scheuermann's disorder, and Dr Silva made no comment on that issue.
84However, Dr Silva went on to state that because of the underlying Scheuermann's disorder, the plaintiff would have been unfit to perform heavy lifting and repetitive bending activities earlier in his career as a labourer, the implication being, this was so before the subject injury. Dr Silva also went on to say that the plaintiff's current back condition would have been the same, without the intervention of the February 2008 incident.
Dr Billett
85Dr Billett's report of 5 July 2012 also reviewed the radiological evidence. He described the degenerative changes in the vertebrae of the plaintiff's thoracic spine as being minor. He based his reported conclusions on what he referred to as the evaluation of the objective findings concerning the plaintiff. He described the plaintiff's condition as still presenting with evidence of the ongoing aggravation of the degenerative changes in the thoracic spine. He expressed the view that the plaintiff was not capable of resuming his pre-injury duties, and he should limit his activities. Like Dr Searle's report, and unlike Dr Silva's report, this report also explained the basis of the plaintiff's ongoing symptoms.
Definition of Scheuermann's disorder
86Dr Silva was the only medical expert to identify the presence of Scheuermann's disorder of the plaintiff's spine. He described this as a classical presentation. That view was based upon his examination of the radiological evidence. No other medical or radiological report tendered in these proceedings made reference to the presence of Scheuermann's disorder in the plaintiff's thoracic spine.
87Since the term Scheuermann's disorder was not defined in any of the medical evidence, in order to achieve a background understanding of the context of it's use in Dr Silva's reports, recourse was had to a range of standard medical dictionaries in common use, in order to identify a broad commonly accepted definition of the term. Such recourse is not a substitute for, or an augmentation of the evidence: Strinic v Singh [2009] NSWCA 15, at [64].
88One such definition is osteochondrosis of the vertebrae : Dorland's Illustrated Medical Dictionary, 29th Ed, WB Saunders, 2000, p 1605. In the same dictionary, osteochondrosis is defined as a disease of the bony growth centres in children in the form of a kyphosis, which begins as a degeneration followed by a regeneration or recalcification. In the location of the vertebrae, it is called vertebral epiphysitis: Dorland's Illustrated Medical Dictionary, p 1287. I note in passing, that kyphosis was specifically excluded in the medical examination of the plaintiff in this case. That said, the definitional inclusion of kyphosis in Scheuermann's disease has not been used as a factor for weighing Dr Silva's report: Strinic v Singh [2009] NSWCA 15, at [64].
89Another definition is epiphysial aseptic necrosis of the vertebral body: Stedman's Medical Dictionary, 26th Ed, Williams & Wilkins, 2000, p 503. In the same dictionary, epiphysitis is defined as an inflammation or excrescence of the epiphysis, which is part of a bony structure developed from a centre of ossification and separated by a layer of cartilage: Stedman's Medical Dictionary, p 586.
90Spondylitis is defined as an inflammation of the vertebrae, a form of degenerative joint disease of the affected portion of the spine: Dorland's Illustrated Medical Dictionary, p 1683.
91These definitions, when read broadly, seem to indicate that where the competing bodies of expert evidence refer to either Scheuermann's disorder on the one hand, and degenerative spinal disease on the other, they are most probably referring to the same entity, but by different nomenclature.
Analysis of conflicting opinions
92Each of the medical experts acknowledged the Expert Witness Code: Schedule 7 to the Uniform Civil Procedure Rules 2005. In presenting expert opinions in accordance with that code, a fundamental duty of an expert witness is to provide reasons in the body of the report, or in an annexure, for each expert opinion expressed in the expert's report: UCPR, Sch 7, cl 5(c).
93On behalf of the plaintiff, it was argued that the report of Dr Silva did not comply with that obligation, whereas the reports of Dr Searle and Dr Billett were submitted to be relevantly compliant with the Code. It was submitted that little weight should be given to the opinions of Dr Silva in such circumstances because his opinions were "ipsa (sic for ipse in the case of the opinion of a male) dixit" which in context, and in plain English, essentially means that Dr Silva's views were based upon an unsupported or unexplained assertion.
94In contrast, the defendant argued that since Dr Searle and Dr Billett had been provided with the reports of Dr Silva for comment, and there was no expressed disagreement with some aspects of the views expressed by Dr Silva, such testamentary silence should be taken to mean that Dr Searle and Dr Billett could not relevantly contradict those aspects of Dr Silva's views: Jones v Dunkel [1959] HCA 8; (1959) 101 CLR 298.
95I consider that the defendant's submission in that regard is too simplistic for acceptance. Dr Silva's views, and the views of the other experts for that matter, must still be analysed for their cogency in the context of the disputed issues, in accordance with the well accepted requirements concerning the content of expert opinions purporting to be expressed in accordance with the rules: Makita (Australia) Pty Ltd v Sprowles [2001] NSWCA 305; (2001) 52 NSWLR 705; Dasreef Pty Ltd v Hawchar [2011] HCA 21, (2011) 243 CLR 588.
96Turning then to the examine the opinions of Dr Silva, and assuming that Dr Silva's reference to the presence of Scheuermann's disorder in the plaintiff's thoracic spine is a reference to the same degenerative condition referred to by the other experts, but not by that name, Dr Silva's opinion as to the consequences of the plaintiff's injury must be evaluated.
97The point at which the experts are in agreement is that there has probably been an aggravation of an underlying degenerative condition in the plaintiff's thoracic spine, by whatever name that degenerative condition happens to be described.
98The point at which there is a divergence of opinions amongst the experts is the consequences of the aggravation, including the duration of the aggravation.
99In his first report, Dr Silva simply stated that the aggravation to the plaintiff's thoracic spine has resolved. His reasons for that view are unstated and therefore his reasons for that view are entirely opaque to analysis. Accordingly, I consider that his opinion in that regard has been proffered with disregard to the requirements of UCPR Sch 7, cl 5(c).
100In proffering the view that the effects of the aggravation have resolved, Dr Silva has not dealt with or explained the plaintiff's continuing experience of pain between his shoulder blades, extending from the level T1 to T10 in his thoracic spine. In that context, Dr Silva has not stated that it was not feasible for the plaintiff to be reporting the continuing presence of such pain, in circumstances where he suggests that the aggravation ceased to have effect, especially where there has been no additional trauma, and before the incident in question, the plaintiff did not have these problems.
101Instead, in his first report, Dr Silva made some qualified comments which could be read as implied criticism of the plaintiff's history and presentation.
102In that regard, Dr Silva made reference to the plaintiff having "recent callosities and work staining on both palms suggestive of recent manual activity probably of a heavy nature", and the presence of "significant pain behaviour features ... (with the presentation being) ... essentially non-organic." The defendant relied upon those comments by Dr Silva to suggest the plaintiff was not as severely affected as he has claimed. In my view, those comments should not be read as being critical of the plaintiff without there being some further explanation from Dr Silva as to what was actually discussed with the plaintiff concerning these matters during the consultation: Mason v Demasi [2009] NSWCA 227.
103In my view, without further explanation, those comments by Dr Silva should not be read critically against the plaintiff. Dr Silva's report does not state why he considered the callosities to be of recent rather than of longstanding origin. In this regard, I accept Dr Searle's criticisms of Dr Silva's view, as set out in Dr Searle's commentary dated 29 July 2012.
104Applying a simple logical analysis to Dr Silva's views, the suggestion the plaintiff has been doing manual work does not necessarily mean that such assumed work involved placing strain on the plaintiff's thoracic spine. The mere suggestion that the assumed manual work was probably heavy is necessarily speculative. The observation of stained palms does not necessarily support Dr Silva's conclusion without an understanding of how such staining actually occurred. These are all matters that should have been raised with the plaintiff by Dr Silva as a matter of procedural fairness in order to consider any comments made by the plaintiff, by way of explanation for these findings: Mason v Demasi. Absent evidence of such a discussion, I consider that very little weight should be placed on this aspect of Dr Silva's opinions.
105In Dr Silva's second, or commentary report, without further examination of the plaintiff, and without taking any further history from him, he has expressed two further and significant views in that commentary, which have no identifiable basis in cogent reasoning.
106The first of Dr Silva's such additional views was that the plaintiff had become unfit to do heavy lifting and repetitive bending at a point in time earlier in his career because of the pre-existing presence of Scheuermann's disorder.
107I find myself unable to accept that opinion of Dr Silva because, without further reasoning, it seems inconsistent with the history obtained from the plaintiff, which I accept, of him having in the past carried out such work both at work and at home without difficulty or incapacity before the subject injury. Dr Silva has not cogently explained how the plaintiff could have achieved such activity without debilitating pain when unfit for those tasks in the pre-injury period. A court should not be left to speculate on such an important matter. I therefore place no weight on that aspect of Dr Silva's opinion.
108The second of Dr Silva's additional views, was that the plaintiff's current back condition would have been the same even without the intervention of the February 2008 incident. Dr Silva said he based that opinion on his clinical observations that he had made in his original report. Dr Silva's original report identified his diagnosis to be a clinical impression of aggravation of Scheuermann's disorder, but resolved.
109In order to understand this aspect of Dr Silva's opinion, it is relevant to again refer to his summary of the clinical examination he carried out of the plaintiff on 27 May 2011. It is necessary to do so in order to determine whether the expressed opinion is supported by the products of the examination to which he referred. Dr Silva's summary of that clinical examination is as follows:
"PRESENT COMPLAINTS
Pain between the shoulder blades and he told me that the pain extends from about T1 to T10 of the spine and over the right shoulder.
EXAMINATION
Ms (sic for Mr) Humphries stood at 5'9" and weighed 80 kg. He was not in any distress and moved with ease and sat comfortably. He undressed and dressed himself with ease but it was noted that his wife was helping him with the sock later on after the examination.
He had recent callosities and work staining on both palms suggestive of recent manual activity probably of a heavy nature.
He moved with ease and had a normal gait. He was able to walk on his toes as well as on his heels and squatted fully.
However, during the rest of the clinical examination there were significant pain behaviour features and the clinical presentation was essentially non-organic.
Although the cervical, thoracic and lumbar curves were normal with no spinal muscle spasm in the cervical and thoracolumbar areas, he restricted spinal mobility in all three sections in a symmetrical fashion to about half the normal range and that was non-organic.
Right and left shoulder abduction and flexion were also restricted to 90° but there was no rotator cuff tenderness or scapular tenderness.
Straight leg raising was 70° in each leg with a negative sciatic nerve stretch test and there was no neurological deficit in the upper limbs or lower limbs.
I think his clinical presentation is essentially non-organic in the context of recent callosities and work staining of both palms. I think his cervical, thoracic and lumbar spines are in DRE Category I."
110If the relevant products of clinical examination Dr Silva had in mind were the callosities and work stained palms, that is clearly a fallacious and unfair means by which to infer that the aggravating effects of the work injury have ceased to have effect.
111Nowhere does Dr Silva actually suggest that the plaintiff's ongoing complaints of pain are not genuine. He does not provide any reasons for the suggestion that, although the plaintiff continues to experience the pain as he described, such pain is not due to the aggravation of the pre-existing condition by the incident in question. Accordingly, I accept Dr Searle's 29 July 2012 criticisms of those opinions expressed by Dr Silva.
112Dr Silva did not explain what he meant by the presence in the plaintiff of pain behaviour features. A court should not speculate on the meaning of such an expression in order to draw an inference that the plaintiff's complaints are not genuine.
113Dr Silva's use of the description "essentially non-organic" to describe the plaintiff's clinical presentation is necessarily ambiguous. It does not directly suggest that the plaintiff is not genuine in his complaints. I therefore do not read that expression as being critical of the plaintiff's presentation in May 2011, especially when, in July 2012, the plaintiff has been diagnosed by Dr Dennerstein as having developed an adjustment disorder, with mixed anxiety and depression, which includes features such as somic anxiety. This is so especially where the unchallenged evidence is that these problems are related to the incident of 22 February 2008. The clear inference is that these problems experienced by the plaintiff were present at the time of Dr Silva's examination.
114On analysing the reports of Dr Silva as outlined above, I consider that the reasons for his opinions that the defendant relies upon as being critical of the plaintiff's claim are not adequately identified, explained or justified. This must necessarily significantly diminish any weight that such reports would otherwise be given.
115Clearly, the opinions of Dr Silva are diametrically opposed to the views expressed by Dr Searle and Dr Billett. Shortly stated, the plaintiff submitted that the opinions of Dr Silva should not be accepted because they are not acceptably explained according to the well known and accepted compliance requirements for expert evidence: Sch 7 cl 5(c); Makita (Australia) Pty Ltd v Sprowles; Dasreef Pty Ltd v Hawchar.
116Turning then to the opinions of Dr Searle and Dr Billett, the essential question to be addressed in assessing their respective reports, is whether the opinions contained in their reports are adequately explained, and whether their opinions are consistent with the known, unchallenged and found facts.
117Dr Searle's opinion clearly stated that the aggravation injury sustained by the plaintiff on 22 February 2008 was persisting in its effects and was permanent, causing the plaintiff to continue to suffer a moderately severe amount of pain. Dr Searle's opinions to that effect made perfect sense when compared to Dr Silva's opinions which failed to adequately explain or deal with the plaintiff's ongoing complaints of pain, in the context of an asserted resolution of the aggravation injury. In contrast, Dr Searle's reasoning was not at all flawed.
118Dr Searle very clearly explained that the underlying pre-injury developmental variant that was evident in the plaintiff's thoracic spine, made him susceptible to a thoracic ligament strain or aggravation of underlying thoracic spondylosis.
119He similarly explained that the earlier incident, which he referred to as having occurred in 2005, in which the plaintiff suffered a temporary minor aggravation in the same area, appeared to resolve completely before the incident which is the subject of this claim. The variation in dates between 2005 and 2006 was not material. From the context of Dr Searle's report, his opinion was obviously based upon the plaintiff's history of having recovered from that earlier incident, an historical account that I have accepted. It is also noteworthy that Dr Searle stated that the plaintiff gave no impression of having exaggerated or over-reacted at the time of his examination. In my view, there were no issues of concern on the face of Dr Searle's report that caused doubt as to the acceptability of his opinions or concerning non-compliance with the Expert Witness Code
120The opinion of Dr Searle, to the effect that the symptomatic effects of the subject aggravation of the plaintiff's spine will continue and get worse with the passage of time, stands to be evaluated according to events that occurred after his December 2010 examination of the plaintiff.
121This then leads to an evaluation of the opinion of Dr Billett, as that opinion was based on a more recent examination of the plaintiff in July 2012, which post-dated Dr Silva's examination by just over a year.
122Dr Billett made no critical comments concerning the consistency of the plaintiff's presentation, or the plaintiff's compliance with the requirements of the physical examination that he conducted. After reviewing his findings on examination and the relevant radiology, Dr Billett identified evidence of ongoing aggravation of pre-existing or underlying degenerative changes, such aggravation being due to the injury on 22 February 2008. Dr Billett clearly based his opinions on the history and his clinical findings, and in particular, on the plaintiff's ongoing complaints of pain, which I have accepted. In my view, there were no issues of concern on the face of Dr Billett's report that caused doubt as to the acceptability of his opinions or concerning non-compliance with the Expert Witness Code.
Conclusion on conflicting medical opinions
123Having evaluated the conflicting medical opinions of Dr Silva on the one hand, and the opinions of Dr Searle and Dr Billett on the other, I have concluded that I do not accept Dr Silva's opinions for the reasons I have already identified. Instead, I prefer the reasoned opinions of Dr Searle and Dr Billett. When all these reports are analysed, the opinions of Dr Searle and Dr Billett are consistent with each other over the time span of the respective examinations, and they are consistent with the history provided by the plaintiff. As such, in my view, they preponderantly outweigh the contrary opinions of Dr Silva in an acceptably reasoned manner, in conformity with the Expert Witness Code, unlike the opinions of Dr Silva, as I have identified.