Mountain Pine Furniture Pty Ltd v Taylor & Ors [2007] VSCA 146

For the TAC (sought but was refused leave to intervene)

**1 I agree with the conclusions reached by Nettle JA for the reasons given by him.

2 I also agree with Ashley JA that the difficulties of interpretation and application of the relevant provisions of the Fourth Edition of the AMA Guides almost certainly arise, in part at least, from the fact that the Guides were drafted and intended for use as a working document by doctors and not with the precision of a statutory enactment.**

3 The issue in this appeal is whether, in assessing the extent of the first respondent's permanent impairment in accordance with ss 91 and 98C of the Accident Compensation Act 1985 and the American Medical Association Guides to the Evaluation of Permanent Impairment (4th ed) ("the Guides"), the Medical Panel is required or permitted to take into account the beneficial effect of surgery on the cervical spine of the first respondent and, in particular, whether the Panel is required to take into account or to exclude from consideration that the surgery has resulted in the eradication of "loss of motion segment integrity".

4 The facts of the matter appear from the reasons for judgment below. On 27 November 1997 the first respondent was injured while driving a truck in the course of his employment with the appellant ("Mountain Pine"). He suffered a dislocation of the interphalangeal joint of the left big toe which was treated by reduction and suturing of an associated laceration. It has left him with a stiff, but otherwise well healed, left big toe. Much more significantly, he also suffered a fracture dislocation of C6-7 with mild spinal canal displacement, as well as what is called, in the Guides, loss of motion segment integrity. This injury was

treated by surgery involving internal fixation and a C6-7 fusion. He has made a good recovery from the surgery but has been left with stiffness and aching most of the time in the sides of the neck, and some pins and needles in the tips of his middle, ring and little fingers of both hands at night. Radiologically, the fusion is sound. The C6 vertebra is fixed 3 mm forward to its normal position on the C7 vertebra. According to the Guides, that positioning is insufficient to qualify as loss of motion segment integrity.

5 On 16 July 1999 the first respondent submitted a claim for compensation pursuant to s 98C of the Act. It was accepted by the WorkCover agent (QBE Mercantile Mutual) by letter dated 20 March 2001. There was however a dispute as to the degree of impairment and thus the following medical question was referred to a Medical Panel pursuant to s 104B(9) of the Act:

"What is the degree of impairment resulting from the accepted injury/s assessed in accordance with Section 91 and is the impairment permanent?"

**6 On 5 January 2004 the Medical Panel gave as its opinion pursuant to s 67 of the Act that the first respondent had a 16% whole person impairment resulting from the accepted injuries to his toe and neck and that, when assessed in accordance with s 91 of the Act, that degree of impairment was permanent.

7 The first respondent sought judicial review of the Panel's decision and on 1 September 2004 obtained a judgment quashing the opinion on the ground that the Panel's reasons were inadequate and directing that the medical question be referred to a differently constituted Medical Panel to be dealt with according to law.

8 On 19 November 2004 a newly constituted Medical Panel (the second and third respondents) answered the medical question as follows:**

"In the Panel's opinion, [the first respondent] has a 16% whole person impairment resulting from the accepted toes [sic] and neck injuries when assessed in accordance with Section 91 of the Act. The degree of impairment is permanent."

**9 The figure of 16% was reached by the Panel by allotting a figure of 1% with respect to the first respondent's toe and 15% with respect to his neck, and applying those figures to the Combined Values Chart found in the Guides.

10 In its report, however, the Medical Panel added this:

"In Section 1.1 of Chapter One on page 1 the Guides state:

'The Guides defines 'permanent impairment' as one that has become static or stabilized during a period of time sufficient to allow optimal tissue repair, and one that is unlikely to change in spite of further medical or surgical therapy.'**

The Panel noted that these statements are in apparent conflict with the following paragraph on page 100 of Chapter Three of the Guides:

'With the Injury Model, surgery to treat an impairment does not modify the original impairment estimate, which remains the same in spite of any changes in signs or symptoms that may follow the surgery and irrespective of whether the patient has a favourable response to treatment.' (Emphasis added.)

On the basis of the available medical information the Panel considers the worker had a fracture disclocation of C6/C7 with posterior element fracture with mild spinal canal displacement, as well as radiological evidence of loss of motion segment integrity (instability) as defined in Section 3.3b of the Chapter Three, prior to the surgery in February 1998. If the Panel assessed impairment resulting from the accepted neck injury prior to the surgery in accordance with Table 70 there would be a whole person impairment of 25% for a cervicothoracic spine Category IV impairment pursuant to Table 73.

The Panel considered that the surgery performed in February 1998 resulted in a successful fusion and that the pre-surgery radiological evidence of loss of motion segment instability does not now exist. The Panel considers the impairment resulting from the accepted neck injury if assessed after surgery in accordance with Table 70 would result in a whole person impairment of 15% for a cervicothoracic spine Category III impairment for a healed posterior element fracture with mild spinal canal displacement which is healed without permanent loss of structural integrity or the presence of radiculopathy or myelopathy, pursuant to Table 73.

The Panel considers that for there to be a meaningful clinical basis for a finding that a certain degree of impairment is permanent, it must be a degree of impairment which is unlikely to change in spite of further medical or surgical therapy. Therefore, as it is clear that surgery did alter the degree of impairment, the Panel concluded that notwithstanding the paragraph on page 100 of Chapter Three of the Guides,[1] the degree of impairment resulting from accepted neck injury in this case should be based on the post-surgery condition.

The Panel therefore concluded that the appropriate impairment category for the cervicothoracic spine is DRE Category III pursuant to Table 73 of Chapter Three, resulting in a whole person impairment of 15%. The Panel considers it is unlikely that any further surgery will be required and the worker's current neck condition has now been stable for a long period of time and therefore this degree of impairment should be regarded as permanent within the meaning of the Guides.

The Panel noted the submission that the Panel should assess impairment in accordance with the Range of Motion model in Chapter Three as the Guides expressly forbid taking into account the effects of surgery when using the Diagnosis-related Estimates (DRE) model. The Panel, for reasons expressed above, does not consider that in this case it is expressly forbidden to take into account the effects of surgery when using the DRE model."

11 The first respondent challenged that second opinion on the ground that the Panel was not entitled to take into account the improvement in his neck condition consequent upon the surgery which is referred to in [4] above. He contended that the Panel had failed to comply with the direction in Section 3.3d of the Guides that, in assessing the degree of his impairment using the Injury Model, surgery to treat an impairment does not modify the original impairment estimate, which remains the same in spite of any changes in signs of symptoms that may follow the surgery and irrespective of whether the patient has a favourable or unfavourable response to treatment.

12 The judge below upheld that contention and remitted the matter to Panel for redetermination in accordance with his ruling. His Honour's reasoning was that:

"In Section 3.3d the Injury (or DRE) Model is described more fully in the following terms:

'The Injury Model attempts to document physiologic and structural impairments relating to insults other than common developmental findings, such as (1) spondylolysis, found normally in 7% of adults; (2) spondylolisthesis, found in 3%; (3) herniated disk without radiculopathy, found in more than 30% of individuals by age 40 years; and (4) ageing changes, common in 40% of adults after age 35 years.

The Injury Model relies especially on evidence of neurologic deficits and uncommon, adverse structural changes, such as fractures, dislocations and loss of motion segment integrity. Under this model, DREs are differentiated according to clinical findings that are verifiable using standard medical procedures.

With the Injury Model, surgery to treat an impairment does not modify the original impairment estimate, which remains the same in spite of any changes in signs or symptoms that may follow the surgery and irrespective of whether the patient has a favorable or unfavorable response to treatment.'

This description makes it clear that evaluation using this model or method concentrates on the degree of severity of the insult on the spine by the traumatic event which caused the permanent impairment, measured by reference to its effect on the patient. It is in this context that it directs the examiner to ignore the effect of surgery. Examples given as illustrations of the use of the Injury Model show that the intention of the Guides is to remove from account any effect of surgery - remedial or adverse. One example, pertaining to the lumbosacral spine, assessed a patient who had a positive result from a disc removal and spinal fusion to treat a herniated nucleus pulposus at L4. The example specifically took out of account the effect of surgery. Another example, closer to the problem in Mr Taylor's case, concerned a patient who had had successful surgery to fuse her C5-C6 joint to treat a large herniated nucleus pulposus between those two vertebrae, with radiculopathy present with respect to C6. Her permanent impairment was also assessed as if the surgery had not been performed.

The Accident Compensation Act 1985 requires the Medical Panel to assess impairment using the AMA Guides. This attempt by the legislature to introduce some degree of objectivity into the assessment of impairment for compensation purposes represents a significant application of the rule of law in an area where one of the fundamental principles of justice - that like cases should be treated alike - has particular importance. Nothing would discredit a compensation system more quickly than the idiosyncratic application of criteria to the determination of an injured person's impairment and hence their entitlement to compensation at a particular level. Although the efficacy of the application of the AMA Guides to achieve a just result for injured people may be debated, as the law stands they must be applied regardless of any personal view of the assessor called upon to make the assessment. Whilst the interpretation of medical matters referred to in the Guides and the exercise of clinical judgment must be left to the medical examiner who is applying them, it is not within that medical examiner's remit to ignore an express direction contained in the Guides as to how a particular objective fact is to be treated in making an assessment. Thus it was not within the power of the Medical Panel in this case to reach its assessment of Mr Taylor's impairment after taking into account the effects of surgery performed on his cervical spine.

That the Guides require the effects of surgical intervention on the spine to be ignored in assessing permanent impairment does not mean that the fact that surgery has been undertaken must be ignored by the assessor. On the contrary, the assessor must ensure that the effects of any surgery are carefully noted so that they can be consciously disregarded in reaching a conclusion as to permanent impairment. If surgery has been successful (as in this case) the assessor looks only at the effect or effects of the trauma on the pre-operation patient, applies Table 70 to those effects (or, where necessary, considers other criteria provided by the Guides to reach an appropriate conclusion) and proceeds to the whole person impairment assessment provided by applying the result obtained from Table 70 to Table 73.

Where surgery has been unsuccessful the task of the assessor may, in some cases, be somewhat more difficult. It is the effect of the surgery which must be ignored in reaching an assessment. Thus, any sign or symptom of the original injury still present after the surgery must be taken into account in applying Table 70. Those detriments which must be ignored are those actually caused by the surgery; that is to say which can be said to have been a result, not of the original trauma, but of the surgery itself. It is only "changes in signs or symptoms that may follow surgery" that are to be ignored; in this instance the word "follow" is synonymous with "caused by". That this is so is reinforced by the Guides' emphasis that it is a favourable or unfavourable response to treatment which must be ignored. Any other interpretation of the requirement that surgery be ignored which did not differentiate between the effect of the original trauma and the effect of the surgery could lead to grave injustice to the injured person. A failure to so differentiate those effects would introduce an unacceptable risk of injustice in the assessment of impairment and thus the assessment of compensation. It is clearly not a requirement of the Guides."

13 Section 91 of the Act provides in part that:

(1) In this Part, a reference to the assessment of a degree of impairment in accordance with this section is a reference to an assessment-

(ia) the A.M.A Guides as applicable subject to guidelines in accordance with sub-section (6), (6A) or (6B); or

(ii) methods prescribed for the purposes of this section-

and in accordance with operational guidelines (if any) as to the use of those Guides or methods issued by the Minister; and...

(8) In this section 'A.M.A Guides' means the American Medical Association's Guides to the Evaluation of Permanent Impairment (Fourth Edition) (other than Chapter 15) as modified by this Act and any regulations made under this Act."

14 The guidelines in accordance with sub-section (6), (6A) or (6B) are for this purpose irrelevant and it is not suggested that there are any operational guidelines which bear on the matter in issue.

"A key tenet [of the Guides] is that the book applies only to permanent impairments, which are defined as adverse conditions that are stable and unlikely to change. Evaluating the magnitude of these impairments is in the purview of the physician, while determining disability is usually not the physicians responsibility."

16 Under the heading of "Impairment Evaluation", Section 1.1 of the Guides states under that:

"... The Guides defines "permanent impairment" as one that has become static or stabilized during a period of time sufficient to allow optimal tissue repair, and one that is unlikely to change in spite of further medical or surgical therapy."

An impairment percentage derived by means of the Guides is intended, among other purposes, to represent an informed estimate of the degree to which an individual's capacity to carry out daily activities has been diminished."

17 Under the heading of "Structure and Use of the Guides" section 1.2 of the Guides states:

"...Before a judgment regarding impairment is made, it must be shown that the problem has been present for a period of time, is stable, and is unlikely to change in future months in spite of treatment."

18 Under the heading "Rules for Evaluations" section 2.2 of the Guides provides:

"Adjustments for Effects of Treatment or Lack of Treatment

In certain instances, the treatment of an illness may result in apparently total remission of the patient's signs and symptoms. Examples include the treatment of hypothyroidism with levothyroxine and the treatment of type I diabetes mellitus with insulin. Yet it is debatable as to whether the patient has regained the previous status of normal good health. In these instances, the physician may choose to increase the impairment estimate by a small percentage (eg, 1% to 3%), combining that percent with any other impairment percent by means of the Combined Values Chart.

In some instances, as with the recipients of transplanted organs who are treated with immunity-suppressing pharmaceuticals or persons treated with anticoagulants, the pharmaceuticals themselves may lead to impairments. In such an instance, the physician should use the appropriate parts of the Guides to evaluate the impairment related to the pharmaceutical. If information in the Guides is lacking, the physician may combine an estimated impairment percent, the magnitude of which would be depend on the severity of the effect, with the primary organ system impairment, by means of the Combined Values Chart.

A patient may decline treatment or an impairment with a surgical procedure, a pharmacologic agent, or other therapeutic approach. The view of the Guides contributors is that if a patient declines therapy for a permanent impairment, that decision should neither decrease nor increase the estimated percentage of the patient's impairment. However, the physician may swish to make a written comment in the medical evaluation report about the suitability of the therapeutic approach and describe the basis of the patient's refusal."

19 Under the heading "The Spine", Section 3.3 of the Guides provides that:

"... In this edition of the Guides, the contributors have elected to use two approaches. One component, which applies especially to patients' traumatic injuries, is called the "Injury Model." This part involves assigning a patient to one of eight categories, such as minor injury, radiculopathy, loss of spine structure integrity, or paraplegia, on the basis of objective clinical findings. The other component is the "Range of Motion Model," described above and recommended in previous Guides editions.

The evaluator assessing the spine should use the Injury Model, if the patient's condition is one of those listed in Table 70.[2] That model, for instance, would be applicable to a patient with a herniated lumbar disk and evidence of nerve root irritation...

The newer Injury Model, which may also be called the "Diagnosis-Related Estimates (DRE) Model," is described in sections 3.3a through 3.3i of this chapter...The Guides user is reminded that each evaluation should include a complete, accurate medical history and a review of all pertinent records, a careful and thorough physical examination, a complete description of the patient's current symptoms and their relationship to daily activates, and all findings of relevant laboratory, radiologic, and ancillary tests.

It is emphasized that if an impairment evaluation is to be accepted as valid under the Guides criteria, the impairment being evaluated should be a permanent one, that is, one that is stable, unlikely to change within the next year, and not amenable to further medical or surgical therapy (emphasis added).

All spine impairment estimates shown in the tables of this section are estimates of whole-person impairments.

The Injury or Diagnosis-related Estimates Model

The Injury Model relies not only on the medical history and physical examination, but also on medical data other than those that relate to the range of motion.

The Injury Model attempts to document physio-logical and structural impairments relating to insults other than common developmental findings, such as (1) spondylolysis, found normally in 7%of adults; (2) spondylolisthesis, found in 3%; (3) herniated disk without radiculopathy, found in more than 30% of individuals by age 40 years; and (4) aging changes, common in 40% of adults after age 35 years.

The Injury Model relies especially on evidence of neurologic deficits and uncommon, adverse structural changes, such as fractures, dislocations, and loss of motion segment integrity. Under this model, DREs are differentiated according to clinical findings that are verifiable using standard medical procedures.

With the Injury Model, surgery to treat an impairment does not modify the original impairment estimate, which remains the same in spite of any changes in signs or symptoms that may follow the surgery and irrespective of whether the patient has a favourable or unfavourable response to treatment.

Henceforth, I shall refer to the last paragraph as "the Section 3.3 Direction".

20 At the end of the section of the Guides devoted to Lumbosacral Spine Impairment, there are two examples, of which the second is as follows:

"Example 2: A 45-year-old woman had onset of back and right-leg pain immediately after a being in a crash. She had a history of mild intermittent back pain but denied ever having had leg pain. Roentgenograms taken in the emergency room on the day of the crash and repeated at a later clinic visit showed significant slipping of L4 on L5 that was measured at 7 mm.

Examination of roentgenograms taken years earlier in an orthopedists's office demonstrated significant spondylolisthesis between L4 and L5.

Conservative treatment of the woman's symptoms was ineffective, and she developed signs of a radiculopathy on the right side, with diminished reflexes and a positive straight-leg-raising test. A magnetic resonance image showed a herniated nucleus pulposus at L4.

The woman underwent an operation for disk removal and one-level spine fusion. She did well after the operation, her signs and symptoms receded, and she resumed full daily activities. Ten months after the injury, when her condition was stable, the physician evaluated her condition.

Impairment: Lumbosacral category III (Table 72, p.110); 10% whole-person impairment.

Comment: The woman had a ruptured disk as a result of the crash. The resolution of her symptoms after a surgical procedure does not reduce the impairment estimate. The slipping of L4 on L5 shown after the crash does not enter into the estimate, because the responsible condition was present years earlier, according to roentgenographic evidence."

21 Finally, for present purposes, at the end of the section of the Guides devoted to Cervicothoracic Spine Impairment, there are three examples of which the second is as follows:

"Example 2: A 28-year-old athlete had a C5 vertebral body fracture with almost 50% compression and had radicular pain in the left arm, which was verified as a C6 level radiculopathy by positive sharp waves in three arm muscles. The man underwent a three-level posterior fusion. After his condition became stable, he had no bladder problems, but he was unable to walk without leg braces.

The patient's impairment was in cervicothoracic category III and also in category VI because of the lower extremity weakness. The category III impairment of 15% would be combined with a 40% category VI[3] impairment representing lower extremity weakness.

Impairment: 49% whole-person impairment; this represents 15% combined with 40% (Combined Values Chart, p.322)."

**22 The essence of the appellant's argument is that it is a key tenet of the Guides that they are directed to the assessment of permanent impairments, and a "permanent impairment" is defined as "one that has become static or stabilized during a period of time sufficient to allow optimal tissue repair and one that is unlikely to change in spite of further medical or surgical therapy."[4] The Guides further expressly provides that, before a judgment regarding impairment is made, it must be shown that the problem has been present for a period of time, is stable, and is unlikely to change in future months in spite of treatment.[5] Consequently, according to the appellant, the construction which the judge put on the Section 3.3 Direction is opposed to a key tenets of the Guides and to the fundamental conception of permanent impairment. As counsel for the appellant submitted, it would also appear to be an inherently unlikely way of going about the assessment of an index which, according to the Guides, "is intended ... to represent an informed estimate of the degree to which an individual's capacity to carry out daily activities has been diminished". She posed the question, rhetorically: why should a system of assessment which has as its avowed objective the assessment of an individual's capacity to carry out daily activities be taken to treat a patient who has had his or her capacity restored by surgery as if he or she were still in his or her pre-surgery state of incapacity? And by way of answer, she submitted that the only logical response is to conclude, as Balmford J did in Bayliss v Transport Accident Commission,[6] that the direction in clause 3.3 is "an oversight" which needs to be ignored.

23 Counsel for the first respondent resisted that contention. He argued that there is no room for doubt about the effect of Section 3.3 Direction. In terms, it requires that the effects of surgery be disregarded, and in turn the Act requires that the assessment of permanent impairment be carried out in accordance with the Guides. So, as the judge in effect put it, there is no room for a discretionary overlay based upon whatever the assessor may conceive to be more logical or sounder medical principles.

24 Additionally, counsel for the first respondent submitted, once it is understood that the Section 3.3 Direction is confined to impairment the result of spinal injury, there is nothing very surprising about an instruction to disregard improvements in signs or symptoms the consequence of surgery. For whatever the nature and success of such spinal surgery as may be undertaken in a given case, it cannot eliminate the injury. Unlike some other forms of surgery, such as surgery to effect the resetting of a broken arm or leg, which may result in perfect or near to perfect results, there is as yet no known technique of restoring a damaged spine to a state of perfect integrity. For the time being, the best that spinal surgery can achieve is some form of musculo-skeletal modification calculated to compensate for the debilitating effects of the insult. In counsel's submission there is also the further consideration that, if one were to ignore the instruction in the Section 3.3 Direction, a number of the examples set out in the Guides (particularly Example 2 set out in [20] above) would make no sense at all.

25 As against that, however, counsel for the appellant contended that so to interpret the Section 3.3 Direction would give rise to just as many problems with the examples, especially the example set out in [21] above, and that in the circumstances one should probably assume that the examples are directed to the calculation of something other than the assessment of the percentage of whole of person impairment for which Tables to 70 to 73 provide. One possibility, she said, was that the Guides are used in a number of jurisdictions in the United States and that the examples are aimed at the statutory purposes of one or other of those jurisdictions.

26 Counsel for the first respondent rejoined that it would be better to deal with the problem of the examples by reading the words "any changes in signs or symptoms that may follow surgery and irrespective of whether the patient has a favourable or unfavourable response to treatment" as confined to favourable responses and such unfavourable responses as are caused by negligent surgery.**

Section 3.3 Direction not an "oversight"

**27 In my view the judge below was correct. It is inherently improbable that the Section 3.3 Direction was an "oversight" and, apart from the absence of any evidence as to the existence or content of the other statutory purposes to which counsel for the appellant referred, it is even more improbable that examples given in the body of section 3.3, immediately after explanation of the conceptions with which that section deals, are included for any purpose other than demonstrating the application of those conceptions to possible fact situations.

28 It is true that the Section 3.3 Direction appears at first to be opposed to a fundamental tenet of the Guides, and it is true that the direction does not fit with the Example 2 set out in [21] above. But the nature of spinal injury is such, and the terms of the direction are so clear, as in my view to show that in the case of spinal injury the direction was intended to override the assessment approach observed elsewhere in the Guides and to substitute for it an assessment based upon the nature of the injury before surgical intervention. As yet there is no known technique of restoring a damaged spine to a state of perfect integrity. The spinal injury once done will forever remain no matter what may be done by way of surgery to alleviate the suffering which it causes. For that reason, a spinal injury is properly to be regarded as an impairment despite any improvement in signs or symptoms the consequence of surgery. Hence the need for the approach in the case of spinal injury for which the Section 3.3 Direction provides.**

Inconsistency between Section 3.3 Direction and example

**29 I acknowledge that there is an inconsistency between the terms of the Section 3.3 Direction and the example set out above in [21]. Assuming the example means that the patient's inability to walk without leg braces (scil. "lower extremity weakness") did not appear until after surgery, and thus was an "unfavourable response to treatment" within the meaning of the Section 3.3 Direction, the direction in terms required that the lower extremity weakness be excluded from consideration for the purposes of the assessment. Yet, according to the example, the lower extremity weakness has been taken into account.

30 I have tried unsuccessfully to construe the Section 3.3 Direction and the example in a manner that will make sense of both provisions. I thought for a time that it may be appropriate to treat the Section 3.3 Direction as directed to "signs and symptoms" as opposed to the injuries from which they result, and so deal with the example on the basis that lower extremity weakness to which it refers was to be regarded as an injury as opposed to a sign or symptom. But with the benefit of counsel's further submissions, I can see that the idea was misconceived. As counsel for both parties in effect submitted, there is no clear distinction between an injury and signs and symptoms for the purposes of the Guides, and possibly for the purposes of medicine generally. Not infrequently, an illness or injury and signs and symptoms are the same thing and understandably much of Section 3.3 of the Guides and the impairment tables which it contains are premised on that basis.

31 I also thought for a while that it might be possible to find an explanation in later editions of the Guides, particularly in the 5th Edition in which the concepts and methods of assessment involved in the injury model have been considerably developed and refined. But with the benefit again of counsel's further submissions, I can see that that idea was also without merit. Each edition of the Guides stands alone and essentially unconnected. The authorship is not necessarily common. Nor are the ideas which are involved. The Act requires the assessment of impairment to be carried out in accordance with the 4th Edition and I accept that one may look no further.

32 In the end, I have come to the view that the Section 3.3 Direction and the example cannot be reconciled. That means, I think, that the drafter must have made a mistake in the terms of one or other of them. Put aside the idea that the Section 3.3 Direction was an "oversight" (which I have rejected), no other possibilities were mentioned. Either the direction was intended to be confined to favourable responses, as counsel for the first respondent suggested was the case, or else the example is wrong.

33 The Section 3.3 Direction is expressed in clear and emphatic terms, as is to be expected of a statement of principle. Not surprisingly, the example lacks the same force, its expression is demotic and it also contains the demonstrably erroneous reference to Category IV to which I have referred. Accordingly, it appears to me that it is less likely that the error is in the direction than it is in the example. It follows as a matter of principle that the example should not be permitted to control the meaning of the direction:[7] falsa demonstratio non nocet cum de corpore constat, and so, to the extent of the inconsistency, the example should be ignored.**

34 So to conclude raises the question of whether, if the facts were as in the example, the injury constituted of the "lower extremity weakness" would be compensable under the Act. To put the problem more generally, would the added impairment involved in an unfavourable response to surgery be compensable? As at present advised, I tend to think that it would be. For the reasons just expressed, I consider that the Section 3.3 Direction would preclude its consideration in the "original assessment of the impairment". But as counsel for the first respondent submitted, one may suppose that the added impairment would constitute a "further injury" occurring while the worker was at a place for medical or surgical treatment within the meaning of s.83(1)(d) of the Act.[8] I add that we have not heard full argument on the point and, strictly speaking, it need not be decided for the purposes of this appeal. But as a matter of first impression it would be surprising if further impairment were not covered in the manner suggested.

**35 Counsel for the appellant put several further arguments against that construction of the Section 3.3 Direction. They may be dealt with relatively briefly.

36 The first was based on Section 2.3 of the Guides, which provides inter alia that:**

"The Guides attempts to take into account all relevant considerations in estimating or rating the severity and extent of permanent impairment and the effects of impairment in terms of the individual's everyday activities. An impairment should not be considered 'permanent' until the clinical findings, determined during a period of months, indicate that the medical condition is static and well stabilized.

A physician who is asked to re-evaluate an individual 's impairment must realize that change may have occurred, even though a previous evaluator considered the impairment to be permanent. For instance, the condition may have become worse as a result of aggravation or clinical progression, or it may have improved. The physician should assess the current state of the impairment according to the criteria in the Guides."

**37 Counsel argued that a literal construction of the Section 3.3 Direction would cut directly across Section 2.3 and so preclude a physician from re-evaluating an individual's impairment.

38 I do not accept the argument. There is nothing in the Section 3.3 Direction which precludes re-evaluations or the assessment of the current state of impairment in the case of spinal injuries. It is just that when undertaking any re-evaluation or assessment of the current state of impairment using the injury method, the physician must bear in mind the overriding Section 3.3 Direction that surgery to treat an impairment does not modify the original impairment estimate, which remains the same in spite of any changes in signs of symptoms that may follow the surgery, and irrespective of whether the patient has a favourable or unfavourable response to treatment.

39 Clearly enough, that is different to the bulk of assessments under other sections of the Guides, where changes due to surgical interventions are taken into account in the case of injuries other than spinal injuries. As has been explained, however, the reason for the difference appears to be the special nature of back injuries. But whatever the reasons for the difference, the requirement is clear. The general Section 2.3 direction does not derogate from the more specific Section 3.3 Direction and to the extent of any inconsistency the latter prevails.**

**40 Counsel for the appellant next referred to Table 71 in Section 3.3 which deals with DRE Impairment Category Differentiators such as "guarding", "loss of reflexes", "decreased circumference, atrophy", "electrodiagnostic evidence" and "loss of motion segment integrity", which a physician may use to help differentiate spine impairments and place them in impairment categories for the cervicothoracic, thoracolumbar, and lumbosacral regions. Counsel argued that the need to consider such differentiators implies a need for post-surgical examination and if so that it would be absurd to require the carrying out of such an examination only then to mandate that the results of it be excluded from consideration in accordance with the Section 3.3 Direction.

41 As I apprehend that argument, however, it takes the matter no further than counsel's earlier submission that the assessment of impairment should be of final impairment, whether as improved or worsened by surgery. I see nothing intractably inconsistent between the use of differentiators and the Section 3.3 Direction that the original impairment estimate is to remain the same in spite of any changes in signs of symptoms that may follow the surgery and irrespective of whether the patient has a favourable or unfavourable response to treatment. The examples given in section 3.3, albeit erroneous in the one respect identified in the Example 2 referred to in [21] above, show how a physician is to use differentiators consistent with the Section 3.3 Direction in a post-operative assessment.**

42 Counsel's final argument was based on references in Table 70 in Section 3.3 to "Previous spine operation" and the ascription of an impairment category to that description in the Table. She submitted that, unless the Section 3.3 Direction were construed in the fashion for which she contended, it would mean that in the case of a victim who is surgically treated for spinal injury and then, say, two years later undergoes further spinal surgery, the assessor would have to "back out" or subtract

the effects of two surgical episodes in order to arrive at the original impairment estimate; whereas if the Section 3.3 Direction were treated as an "oversight", as she suggested it should be, all that would be required would be the one final assessment of impairment as it is after the two surgical episodes.

43 I do not see the problem. Table 70 lists "previous spine operation" and attributes to it an impairment category in order to facilitate the assessment of impairment associated with a later injury; not the original impairment assessment of a first or earlier injury. So, for example, if a victim who has undergone spinal surgery suffers a further injury, the impairment associated with that further injury is assessed by looking at the victim's condition as it is after the further injury and then subtracting from the degree of impairment thus assessed the degree of impairment attributed by Table 70 to the earlier surgery. On the other hand, if a victim suffers only one injury, and undergoes surgery for that injury, any assessment of the impairment the consequence of the injury excludes from consideration any changes in signs or symptoms that may follow from the surgery irrespective of whether the patient has a favourable or unfavourable response to treatment. In that event, there is no question of "Previous spine operation" of the kind referred to in Table 70.

44 For the reasons given, I would dismiss the appeal.

**45 I have had the advantage of reading in draft the reasons for judgment of Nettle JA. I agree with his Honour's conclusions, for the reasons which he gives.

46 I should add this. It was the consequence of ss 91(1)(a)(i), (8) and 104B(9)(a) of the Accident Compensation Act 1985 ("the Act")[9] that the first respondent's degree of**

impairment fell to be assessed under the Fourth Edition of the AMA Guides. The Guides are not written as a lawyer would write them, for they are not a lawyer's document. They are a document written by doctors, making use of medical concepts and language, for use by doctors. Even so, I suspect that the document is in some respects, at least, not easy for even doctors to apply - witness the response of the Panel in the present case.

**47 Given this unfamiliar territory, the consequence of the Act is nonetheless that this Court must place a construction on the relevant part of the Guides. Its function is similar in concept, but quite dissimilar in substance, to the issues of construction which it commonly faces.

48 Different things said at different places in the Guides might be said to point in different directions with respect to the correct outcome of the process of construction required by the present case. But in the end, I consider, the analysis undertaken by Nettle JA provides a very sound explanation why the so-called "injury model," which applies to quite specific types of injury-caused impairment, should be applied in the manner which has found favour with his Honour, and which found favour with the learned judge below.**

[1] That is the emphasised passage set out above.

[2] Table 70 includes "Posterior element fracture with spinal canal displacement or radiculopathy, healed, stable (Category III), as well as loss of motion segment integrity (Category IV).

[3] In the text, this is printed as "IV" but it is a misprint. "IV" is demonstrably wrong.

[4] Guides, Foreword at p 5; and Chapter 1, Impairment Evaluation at p 7; or as described in the glossary at p 315.

[5] Guides, Chapter 1 at 1.2 Structure and Use of the Guides, at p 9.

[6] [2004] VSC 102; (2004) 9 VR 267.

[7] Cf Transport Accident Commission v Elworthy [2007] VSC 48, [23] (Kaye J).

[8] Kidman v Sefa [1996] VicRp 8; [1996] 1 VR 86, 88-9; Dunn v Harrison [2002] VSCA 125; (2002) 8 VR 596, 599.

[9] Section 91(1)(a)(i) and (ii) having nothing to say about the matter, and no "operational guidelines" being said to be of relevance.