Skip to Content, Skip to Navigation

Safeguard OSH Solutions - Thomson Reuters

Safeguard OSH Solutions - Thomson Reuters

Accident Compensation Cases

Waitemata Health Ltd v Ace Insurance Ltd (DC, 07/03/02)

Judgment Text

Judge M J Beattie
The issue in this appeal is whether the decision of the Reviewer, Miss K G Davonport, Barrister, dated 21 June 2000, determining that the second respondent was entitled to cover under the Act in respect of a gradual process injury arising from her employment with the appellant, was correct. 
That review decision in fact overturned the decision issued on behalf of the first respondent, as the insurer of the appellant, issued on 12 October 1999 whereby the first respondent declined to grant cover to the second respondent for her claimed gradual process injury. 
The second respondent was at all material times a Dental Therapist employed by the appellant. At the time the first respondent made its primary decision to decline cover, the second respondent was aged 46 years. 
The second respondent graduated as a Dental Therapist in 1972 and worked as such until 1979 when she ceased work to have her family. In 1986 she retrained and commenced working full-time again and was working full-time in the employ of the appellant up to and including events which occurred in 1999 / 2000. 
It should be noted that the appellant was the successful tenderer for the provision of dental services for children from pre school to Form 2 in the Greater Auckland area. The second respondent's principal areas of work were in the South Auckland region. 
In her evidence, the second respondent stated that her work-load as a Dental Therapist was building up and this was particularly so in 1998 and she said by the end of that year she was exhausted and that whilst she began to experience some pain in her right arm from time to time she did not realise this was a warning sign. 
In March 1999, whilst out walking one evening, she suddenly experienced the onset of excruciating pain in her right arm and shoulder. She also experienced a tingling feeling in her palm of her right arm. These sensations resolved after about an hour but that night in bed she developed further pins and needles. In the morning her symptoms had gone. She continued working and over the next few months she began to experience the feeling of heaviness in her right upper limb at night and she began waking with shoulder and upper arm pain, heaviness and aching. 
On 19 July 1999, the second respondent completed a Staff Incident Accident form in which she identified her aching right arm and indicating that it had occurred at her work place. 
In September 1999, the second respondent and her GP, Dr Alberts, completed an Accident Insurance Treatment Certificate which stated a diagnosis of rotator cuff syndrome and which was said to have come on by recurrent use of her right arm with drilling and the use of instruments in her occupation as a Dental Therapist. Her GP referred her to physiotherapy for treatment at this time. 
On 11 September 1999, the second respondent was seen by Dr C T C Kenny, a Consultant Occupational Physician employed by the appellant in its Occupational Health and Safety Service at North Shore Hospital. Following an interview and examination of the second respondent, Dr Kenny provided the first respondent's agent with a report. 
In his report, Dr Kenny noted that the second respondent had not displayed any specific acute injury nor had she participated in any potentially provocative activities at about the time of the onset of her symptoms. He advised that his examination findings were consistent with the development of a rotator cuff syndrome. He recommended that imaging studies be undertaken to further identify the nature and site of any pathology. 
It was Dr Kenny's advice at that time that there was no evidence that there were any properties or characteristics in the second respondent's work environment that were likely to have caused or contributed to her condition. He further advised that there was no epidemiological evidence that Dental Therapists or other groups doing similar work and using similar equipment and postures were any more likely to develop rotator cuff pathology than those not undertaking such work. 
It was as a consequence of Dr Kenny's advice that the first respondent, by its agent Injury Management New Zealand (IMNZ), advised the second respondent that her claim for cover was declined. The reason given being that there were no properties or characteristics that occurred in her work environment that had contributed to her symptoms. 
At the direction of Dr Alberts, the second respondent was referred to Dr Chris Walls, Occupational Medicine Specialist, for a second opinion, and he saw and examined her on 14 October 1999. 
In his report, Dr Walls identified that the second respondent displayed a mild rotator cuff syndrome, but that she also had some work related upper limb disorder which he indicated was OOS. He referred to the NIOSH booklet Muscular Skeletal Disorders and Work Place Factors, where that booklet stated that there was evidence of a relationship between the repeated or sustained shoulder postures with greater than 60° flexion or abduction in shoulder MSDS. There was evidence for both shoulder tendonitis and non-specific shoulder pain and Dr Walls considered that the second respondent's operative procedures would easily fit into this category. 
Dr Walls went on to state: 
“Work related upper limb disorder (forearm pain) is a very common complaint amongst Dental Therapists. It has arisen I believe because of the prolonged and often static postures. They must adopt with their arms and hands while carrying out procedures, the considerable force that sometimes needs to be applied and the difficult ergonomics of Dental Therapy amongst school children. There has been an increase in the workload which has coincided with an increase in WRULD amongst Dental Therapists and this is too consistent in my opinion to be simply written off to the odd disgruntled Dental Therapist. ”
The second respondent sought a review of the first respondent's primary decision. 
For the purposes of the review hearing, the appellant was referred to Dr Evan Dryson, Occupational Medicine Specialist. He saw and examined the second respondent on 24 February 2000 and he reported to the second respondent's counsel. It was his diagnosis that the second respondent suffered from regional pain syndrome and it was Dr Dryson's advice that such syndromes could be caused by static fixed muscle postures during work and that he considered that this was the case with the second respondent. 
At the Review hearing, both Dr Dryson and Dr Kenny gave evidence and the Reviewer noted that they gave conflicting opinions about whether the second respondent had suffered a personal injury for which she was entitled to cover under the Act. In her decision, the Reviewer advised that she preferred the evidence of Dr Dryson and therefore ruled that the second respondent was entitled to cover under the Act. 
The appellant, as the employer, has now appealed that decision to this Court contending that the Reviewer was in error in coming to the decision she did. 
For the purposes of appeal to this Court, counsel for the appellant obtained leave to introduce further expert evidence from Professor Des Gorman, Head of Occupational Medicine at Auckland University, School of Medicine. Evidence from Prof Gorman was initially presented in the form of a report dated 14 November 2000. At the hearing of this appeal, the Court heard evidence from all three Occupational Medicine Specialists, namely Dr Kenny, Dr Dryson and Prof Gorman. In addition to that expert evidence, the Court also received written briefs of evidence, which were accepted by counsel for the second respondent, from two senior employees of Waitemata Health Limited involved in the administration of the Auckland Regional Dental Service operated by Waitemata Health Limited. 
“The Specialist Expert Medical Evidence 
Evidence of Dr C T C Kenny 
Dr Kenny advised that he was a Physician specialising in Occupational Medicine and had been so for twenty years and had been vocationally registered as a medical specialist in this field for 5 years. Dr Kenny advised that he was employed by Waitemata Health as a Consultant Physician in the area of Occupational Medicine. The main points of his evidence may be summarised as follows: 
Mrs Westlake's presentation was notable for the complete absence of any relationship of her symptoms to her work, both before and after the sudden onset of her right shoulder pain. Mrs Westlake was suffering from rotator cuff syndrome due to degenerative changes within the rotator cuff mechanism in the shoulder region. Radiographic studies confirmed classifications in this region, consistent with such a tendinosis; 
Dental Therapists, like many other occupations, perform a variety of shoulder movements throughout a cycle of activity which would typically be at least 5-10 minutes if not more; 
No Dental Therapists maintain upper limb postures for prolonged periods which may lead to cervico-thoracic and upper limb muscular fatigue. There is no evidence that this results in or contributes to rotator cuff calcific tendonitis; 
It is possible that a calcific tendonitis could be the triggering factor for a chronic pain syndrome but again there is no relationship of such a condition to a work related injury; 
He does not agree with the statement made in the Introduction to the Dental Therapists, Best Practice Guide on the basis that there is no credible evidence that Dental Therapists musculoskeletal pain is on the basis of work practice. There have been no studies done on Dental Therapists. 
The Waitemata Health Dental Therapy Survey of 1996 is only evidence of OOS symptoms but not of musculoskeletal pain disorders; 
He accepts the further statement made in that 1996 survey that Dental Therapists with over 15 years service are at a greater risk of musculoskeletal injury; 
He accepted that sustained muscle tension involved with difficult working conditions puts the therapist at risk of muscle problems. 
He accepted the statement in the OSH report to Waitemata Health Dental Therapists 1998 which set out the hazards which contribute to OOS symptoms amongst Therapists and that they can cause musculoskeletal discomfort; 
He disagreed with the finding in that OSH report that dental therapy had the potential to cause serious harm by the nature of the job; 
His diagnosis of Mrs Westlake as having rotator cuff tendinosis was an age related process and involved physiological changes brought about by natural consequences of the body. It involved structural changes which occur naturally — these are micro anatomical changes and do not constitute injury even if there is pain. 
Evidence of Prof Des Gorman 
Prof Gorman has a personal Chair in Medicine at the University of Auckland and is Head of Occupational Medicine at the Faculty of Medical and Health Sciences. Prof Gorman is very highly qualified. 
In November 2000, Prof Gorman carried out a clinical audit by file review on Mrs Westlake's case, the clinical records being provided by Dr Walls, Dr Kenny and Dr Dryson. Points made by Prof Gorman in that report are as follows: 
An analysis of the clinical findings of Dr's Kenny and Walls supports their diagnosis that Mrs Westlake had a rotator cuff syndrome. 
It is quite possible to rationalise the diagnostic discrepancy being that 5 months later Dr Dryson could find no signs indicative of a rotator cuff syndrome. 
The natural history for many acute rotator cuff syndromes is for healing and resolution of symptoms. The time frame for Mrs Westlake is consistent with normative data in this context. 
Some patients, following an acute musculoskeletal disorder, do progress to a regional pain syndrome despite resolution of the apparently provocative process. 
There is no data from even reasonably objective studies to establish a causative linkage between work process and regional pain syndrome in the absence of some form of antecedent injury. 
The quality of the epidemiological studies which have considered whether rotator cuff syndrome is a plausible consequence of work processes is very poor. 
There are non-work risk factors which appear to be significantly associated with shoulder musculoskeletal disorders such as diabetes, being female, some rheumatic conditions, psycho-social factors, stress and disease. 
There is a possible association that highly repetitive work involving shoulder, and work where there is repeated or sustained shoulder postures at greater than 60°, of flexion or abduction. 
To analyse this difficult epidemiological milieu it would be reasonable to conclude that work as a Dental Therapist is a possible cause of a rotator cuff syndrome from the perspective of a gradual process injury. 
The difficulty in this formulation is that Mrs Westlake had no pain at work prior to the sudden onset of shoulder pain. As such, a work injury is possible but not a good explanation of her clinical state. ”
Prof Gorman gave evidence at the hearing and expanded on his statement that the epidemiological studies were of poor quality. In particular, he identified the surveys that had been mentioned by Dr Dryson in support of his opinion, namely the Occupational Health Dental Therapy Survey report 1996 compiled by Dr Martin Robb, The Waitemata Health OSH Report, February 1998, and the Distribution of Occupations in Two Populations and Pain carried out by Dr Dryson and Dr Walls. In addition, Prof Gorman criticised some surveys published in The American Journal of Industrial Medicine, to which the Dryson / Walls report had referred. Prof Gorman advised that that particular journal was one with a low impact factor and would be regarded as C Grade. 
Prof Gorman stated that those surveys did not reach statistical significance. Prof Gorman's exact words on this matter were as follows: 
“If one takes a critical view of the bio mechanics, there are no work factors which are statistically significantly associated with an increased disorder of shoulder disorders / frequencies of shoulder disorders. If you take issues such as sustained abduction, and flexion beyond 60° and repetitive hard work, it doesn't reach statistical significance if you apply critical tests to it. So the argument that prolonged work in sustained abduction and flexion in this range, from here up, doesn't reach critical statistical evaluation but it is probable. So it is the level of statistical likelihood, not the level of statistical reasonable certainty where you argue for example you'll accept a 5% chance of being wrong, if that's the threshold you adopt. And this doesn't approach that. So the first thing to point out when you argue about shoulder disorders, there are two things which I can point out, first is that the data showing that these work factors are statistically related to outcome do not reach statistically significance. The second is that the background noise in the community is very high which makes it very hard to prove that point. And one of the things which bedevils attempts to show relationships between work and a lot of diseases is that the background prevalence is high, the background noise is high …  ”
Prof Gorman advised that the phrase “statistical significance” meant that there was a 95% probability and that this was the usual test required in medicine to establish a proposition. 5% was allowed for random chance. Prof Gorman advised that if a proposition was found to be plausible it had attained the level of probability but not the level of statistical significance. 
In cross-examination by Miss Callanan, Prof Gorman did accept that the assessments referred to in the Introduction to the book on Best Practice Guidelines for Occupational Safety and Health in Dental Therapy Practice prepared by OSH and Waitemata Health, that ergonomic assessments of dental therapists have found strong links between equipment and work practices resulting in gradual process injuries. Prof Gorman said that he accepted that assessments had established that dental therapists had musculoskeletal symptoms but not necessarily gradual process injuries. He considered that the same was true of the other groups of workers such as clerical, bank employees and workers in the insurance industry. 
In further cross examinations from Miss Callanan, Prof Gorman advised that he accepted that it was plausible that dental therapists who work overhead and who work with a lot of shoulder flexion and abduction are at risk of shoulder injuries and it was accepted despite the fact that it had not reached the level of statistical significance. 
Evidence of Dr E W Dryson 
Dr Dryson is a specialist Occupational Physician and is registered as such on the New Zealand Register of Specialists. Dr Dryson has provided Occupational Medicine services under contract to the Occupational Safety and Health Service of the New Zealand Department of Labour (OSH) since 1992. He has published a number of research articles involving Occupational Medicine topics. 
Dr Dryson examined the second respondent on 24 February 2000 and in his report on 1 March 2000, he noted that in late 1998, Mrs Westlake had developed aching in her right upper arm which has persisted since and that there was no obvious precipitant. Dr Dryson's examination did not confirm rotator cuff syndrome and an ultra sound scan showed no abnormality and he concluded that she had a regional pain syndrome as the cause of her ongoing symptoms. ”
The various points made by Dr Dryson in his evidence were as follows: 
It is extremely likely that years of work as a Dental Therapist with the arm raised has caused the inflammatory damage to the tendon and that the episode of pain while walking reflected this previous inflammation. Both Dr Walls and he agreed that a regional pain syndrome was in fact present. 
A regional pain syndrome would not be caused by an activity such as swinging the arm while walking but if Mrs Westlake was in the process of developing a pain sensitisation state due to other activity at work, it is quite plausible that pain could have appeared to have started during a specific activity even though it was outside of work. 
There is published medical literature evidence that dental staff including dentists and dental hygienists do have a high rate of musculoskeletal symptoms. 
The recent publication produced by Waitemata Health entitled Best Practice Guidelines for Occupational Safety and Health in Dental Therapy practice indicates that Waitemata Health have accepted the premise that dental therapists, by their occupation, have a previous position to gradual process injuries. 
Dr Dryson's survey, published with his colleague, Dr Walls, which explored the occupational categories of known patients with regional pain syndromes, showed that there are highly significant associations with some occupations and from which it can be said that it is plausible that the association is a causative one. 
In his view it is entirely plausible that Mrs Westlake's regional pain syndrome has arisen directly from the nature of her employment at Waitemata Health. 
In 1997 he was a co-participant in an investigation carried out by OSH into reports of musculoskeletal pain by number of dental therapists employed by Waitemata Health. 
In the course of the investigation, nine clinics were visited and work practices observed first hand. A number of therapists were interviewed and observed. 
As a result of this investigation, it was considered that there were factors in the dental therapy environment which had caused the musculoskeletal symptoms. These included the following identified causative factors: 
Static hand and shoulder positioning. 
Repetitive manual tasks. 
Poorly set up workstations. 
Heavy hand held dental equipment, primarily designed for male dentists. 
Working without an assistant for some procedures. 
Stress from demands of parents and working in isolation. 
Workloads increasing. 
The need to cope with backlogs of patients. 
With this first hand background, he concluded that Mrs Westlake's regional pain syndrome was a consequence of her work as a dental therapist with Waitemata Health. 
The criteria of s 33(2)(a), (b) and (c) are all met. 
Work which is done above 60° of elevation is accepted by NIOSH as being ten times more likely to result in musculoskeletal disease. 
The hearing of this appeal occupied two full days and much of it was taken up with the hearing of evidence from the medical experts and whilst it must be acknowledged that the hearing did involve in fact two appeals relating to two dental therapists employed by Waitemata Health, the bulk of the evidence was evidence which related to both as the appeals involving each were quite similar. 
Whilst I have not referred to the submissions of counsel hitherto, those submissions have been noted and are incorporated where appropriate in this decision. Suffice is to say, the issue requiring determination is one involving an assessment of the medical evidence in relation to the criteria required to be satisfied by s 33 of the Act, and as such the issue is one of fact rather than one of law. 
It is the appellant's position essentially that there is no evidence which could satisfy the standard of proof necessary that Mrs Westlake has suffered a gradual process injury arising from her employment as a Dental Therapist with Waitemata Health. 
As her first submission, Miss Mechen, counsel for the appellant, submitted that a regional pain syndrome was not itself an injury and that therefore there was insufficient evidence that Mrs Westlake had suffered a personal injury pursuant to s 29 of the Act. In the alternative, counsel submits that, if it be established that Mrs Westlake had suffered a physical injury, then she cannot meet the criteria of s 33(2) of the Act. 
In general terms Miss Callanan, counsel for the second respondent, submitted that the evidence did establish, firstly, that the second respondent had suffered a personal injury within the meaning of s 29 of the Act and that the criteria of s 33(2) had been satisfied. 
Dealing firstly with the question of personal injury, it seems to be accepted by all the specialists that Mrs Westlake was, at the time the appellant made its decision to decline cover, displaying the symptoms of a regional pain syndrome. The evidence of Dr Dryson, confirmed as it was by the assessment of Prof Gorman, certainly establishes that fact beyond any question of doubt. However, I find that simply because Mrs Westlake was at that point in time displaying only the symptoms of a regional pain syndrome, it does not mean that that syndrome was not as a consequence of personal injury. 
The evidence from Dr Walls and Dr Kenny, who both saw Mrs Westlake much earlier than Dr Dryson, is to the effect that she was suffering from rotator cuff syndrome. It is also to be noted that Mrs Westlake's own GP gave that as her diagnosis when she was first consulted. I heard no evidence which would indicate that a rotator cuff syndrome was not considered a personal injury and indeed it seems to be accepted as being a type of injury that can arise from certain conditions and circumstances of the work place. Indeed, Prof Gorman in his report of 14 November 2000 stated that it would be reasonable to conclude that work, as a Dental Therapist is a possible cause of a rotator cuff syndrome from the perspective of a gradual process injury. 
Accordingly I find that the evidence does establish that Mrs Westlake did suffer a personal injury in the form of a rotator cuff syndrome. Furthermore, I find from the evidence, particularly that of Prof Gorman, that it is an accepted medical fact that a person can progress to a regional pain syndrome following an acute musculoskeletal disorder despite the fact that that disorder may have resolved. In other words that which may have provoked the progression to a regional pain syndrome can itself resolve. 
In his report of 14 November 2000 Prof Gorman who does accept that Mrs Westlake's regional pain syndrome could have occurred from the antecedent injury of rotator cuff syndrome, thereupon went on to consider whether the latter would be a plausible consequence of her work processes. 
It was at this point, that Prof Gorman embarked upon his critique of the epidemiological studies that had been made and some of which were relied upon by Dr Dryson to promote the cause of Mrs Westlake. 
Having seen and heard the three experts, and in particular Prof Gorman and Dr Dryson as they were the principal advocates for the respective positions of the appellant and the second respondent, I have come to the conclusion that they are not indeed taking opposite stances to the fundamental question which this Court is called upon to consider. That question being whether the rotator cuff syndrome diagnosed as having been suffered by Mrs Westlake had been caused by her work place practices or procedures. 
Dr Dryson gave evidence, both from his study of overseas research, and of his own involvement in the OSH survey carried out on Dental Therapists employed by Waitemata Health and it was his conclusion that the nature and range of work tasks required to be performed by Dental Therapists and as they were so performed by Mrs Westlake, did give rise to a high degree of probability of suffering a musculoskeletal injury. I have earlier set out the conclusions which his 1997 / 98 report came to and it must be noted that this report was specific to Dental Therapists. 
Although the appellant now seems to be arguing a contrary position, it is on record in its Introduction to its publication of Best Practice Guidelines for Occupational Safety and Health in Dental Therapy Practice as follows: 
“A review of available literature identified clear links between reports of pain and those tasks that involve high precision work and sustained static loading in the neck — shoulder region, combined with a flexed and rotated cervical spine. 
Ergonomic assessments of dental therapists / assistants have found strong links between equipment and work practices resulting in gradual process injuries. Repetitious hand movements result in cumulative trauma disorders such as tenosinivitus, carpal tunnel syndrome, tendonitis and bursitis. These are aggravated by certain hand and wrist positions, particularly in combination with forceful exertions. ”
The difference between the opinion held by Dr Dryson and that by Prof Gorman is that from a pure medical research perspective, Prof Gorman considers that the research and the surveys and the reports that have to date been presented on this topic are not sufficient to elevate the proposition to a state of statistical significance, that state being reached when there is a 95% probability with the remaining 5% being allowed for random chance. 
However when pressed, Prof Gorman did acknowledge that if the issue were to be put at a lower standard, namely the standard required for a judicial determination, then those surveys did establish the propositions to a plausible degree and by plausible he accepted that it satisfied the legal standard known as the balance of probabilities. One of the main objections Prof Gorman had about it not reaching the required level of statistical significance was the background noise of the community being considered high when looking at this particular question. By background noise he refers to the prevalence in the community of the particular conditional instance which is the subject of the survey. 
That is why he considered that there were no work place factors which were statistically significant although he considered that sustained abduction beyond 60° and repetitive flexion were factors which made it plausible that musculoskeletal injuries could arise from work place situations where those conditions were found. 
In summary then I find that the difference between Prof Gorman and Dr Dryson is one of degree and not unnaturally Prof Gorman, from his perspective, is looking at the issue from the point of view of pure medicine and the extremely high standard that any medical research would need to meet before it could be accepted as an established medical proposition or principle. 
Referring now to the particular circumstances of Mrs Westlake, I find that the evidence does establish that her particular work practices and tasks did involve the features which could give rise to her rotator cuff syndrome and that she did so suffer that personal injury as a consequence of her work as a Dental Therapist. 
In view of the findings I have made, relating to the evidence on matters which are relevant to determine the criteria of s 33(2) (a), (b) and (c), I find that the criteria stated in those statutory provisions have been satisfied and that the regional pain syndrome which is the present condition suffered by Mrs Westlake is indeed a progression from her musculoskeletal disorder which she suffered in the course of her employment and is that disorder for which she is entitled to cover and with the ongoing consequences of the same also being entitled to be regarded as consequential upon that personal injury. 
For the foregoing reasons therefore the reviewer's decision is confirmed and this appeal is dismissed. I allow the second respondent the sum of $2,000.00 costs together with the costs associated with Dr Dryson giving evidence at the hearing. Those costs are payable by the appellant. 

From Accident Compensation Cases

Table of Contents