70 Clause 4.30 acknowledged that Table 15-3 did not adequately account for the effect of surgery upon the impairment rating for certain disorders of the spine. Operations where the radiculopathy had resolved were to be considered under the DRE category III (AMA5, Tables 15-3, 15-4, 15-5). However, Table 4.4, which formed part of that clause, indicated additional ratings which were to be combined with the rating determined using the DRE method where an operation for an intervertebral disc prolapse or spinal stenosis had been performed and where there was residual radiculopathy following surgery. Table 4.4 relevantly provided that, in the case of impairment of the lumbar region, there having been a discectomy, or single-level decompression or with residual signs and symptoms, that 3 per cent was to be combined with the impairment rating determined using the DRE method.
71 There was no direct evidence at the trial about whether or not the respondent had suffered a 15% degree of permanent impairment as required by s 151H(1) of the WC Act. The respondent sought to establish that proposition by tendering, among others, reports the appellant had obtained from respectively Dr Connelley and Dr Harvey. It was by taking the second of those reports into account and adjusting it, as we shall shortly explain, that her Honour was able to conclude that the respondent satisfied the 15% threshold.
72 The primary judge approached the case on the basis that it was a matter for the court to determine whether the respondent had established that he had suffered a degree of whole person impairment that was at least 15% using DRE and applying the abovementioned provisions of the Guides (Red 35-36). This was in accordance with the manner the issue was addressed at trial.
73 Her Honour first addressed the respondent's medical reports. She referred to a report from Dr J Harrison of 29 March 2004 which diagnosed the respondent as having sustained "significant postero-lateral disc protrusion with sequestrated disc at L5/S1 on the right hand side which had responded to a decompressive laminectomy but with continuation of some radiculopathy of the right leg." Dr Harrison thought the condition substantially attributable to the accident as to work described. Her Honour noted that Dr Harrison had made no assessment of impairment but concluded that "clearly his opinion places the respondent within the guidelines of 4.4 of the table", referring to Table 4.4 of the Guides.
74 In Dr Harrison's opinion, the respondent was unfit for employment up to December 2001 and thereafter fit for light restricted duty until the end of December 2002. From that time, the doctor thought him fit for light restricted duties but unfit for heavy labouring work or work involving repetitive lifting, bending or carrying, or walking on uneven ground, because of the residual problems with his right leg.
75 The judge then dealt with a report from Dr G Bonnette whose diagnosis was that the respondent had suffered a ruptured L4/5 disc producing a right L5 nerve root compression. Dr Bonnette did not express any opinion as to a percentage of permanent impairment. His view was, however, that the respondent continued to be partially unfit with restrictions on lifting.
76 Her Honour then dealt with the appellant's medical reports tendered by the respondent. Dr Connelley's recorded history noted a prior history of backache going back over six or seven years, but with the respondent insisting that this was only of the type that might come after very heavy labouring work. In his report of 15 June 2004 Dr Connelley opined that the respondent had suffered a permanent impairment of 10% of a whole person (ie the bottom end of the scale of 10%-13% for DRE Lumbar Category III) based on a history of significant disc herniation with some good improvement following surgery for radiculopathy. He also assessed the respondent as having a 5% of a most extreme case level of impairment of his right leg because of the persistence of radiculopathy and the evidence of a weak right ankle jerk, which he translated into a whole person impairment of 2%. He therefore concluded that the respondent had a 12% whole person impairment.
77 The judge correctly observed that Dr Connelley's assessment did not appear to be in accordance with Table 4.4.
78 Her Honour then turned to Dr Harvey's reports.
79 Dr Harvey first reported to the appellant's solicitors on 17 February 2003 on which occasion he diagnosed the respondent as having an L4/5 disc protrusion with nerve root compression (Blue 264). He described the condition as essentially degenerative in nature, while noting that it could have been aggravated and the onset of symptoms precipitated by "the incident [involving falling as the respondent stepped down from a crane] that occurred in the Cessnock Correctional Centre on 9 [sic] August 2001".
80 As the primary judge observed, Dr Harvey recorded that operative treatment had been performed after the fall at Cessnock. On examination, Dr Harvey noted continuing complaints of pain in the lower back radiating down to the outer aspect of the right lower limb to the right foot.
81 In a second report, also dated 17 February 2003, Dr Harvey opined that the respondent had a 10% whole person impairment and would fall into DRE Lumbosacral Category III, a patient with a radiculopathy. He said he believed his assessment was in accordance American Medical Association's "Guides to the Evaluation of Permanent Impairment" (4th Ed.) (Blue 266).
82 Dr Harvey reported again on 31 March 2004. It is apparent that he had been asked how much of the respondent's impairment was due to the injury he suffered in August 2001 and how much to any pre-existing degenerative changes. After noting that the matter whether the respondent had, in fact, suffered pre-existing degenerative changes depended upon a judicial assessment of the respondent's credibility, he expressed the opinion that if the statement recorded at John Hunter Hospital on 6 October 2001 that the respondent had suffered severe back pain over the past six or seven years was true, then he regarded only 50 percent of the respondent's impairment to be as a result of the 2001 incident (Blue 267).
83 Dr Harvey's final report was dated 28 June 2004 and responded to a letter of 4 June 2004 (Blue 268). That letter was not in evidence but it is apparent that the doctor had been asked to make an assessment of impairment using the WorkCover Guides which he thought was "a little different" because it was based on the 5th Ed. of the AMA Guides. Dr Harvey continued:
Under these Guides, the patient would fall into DRE Lumbar Category III. Under these Guides, one is allowed to make an assessment between 10-13% according to how much his back condition interferes with his activities of daily living. If one therefore took the most liberal view he would be assessed as having a 13% whole person impairment.