Holden v Accident Compensation Corporation

IN THE DISTRICT COURT AT WELLINGTON [2012] NZACC 170 UNDER The Accident Compensation Act 2001 IN THE MATTER OF an appeal pursuant to section 149 of the Act (Appeal No. ACR 805/10) BETWEEN MARK HOLDEN Appellant AND ACCIDENT COMPENSATION CORPORATION Respondent Hearing: 23 March 2012 Appearances: Ms K Lau for appellant Ms A K Miller for respondent Judgment: 16 May 2012 RESERVED JUDGMENT OF JUDGE D A ONGLEY [1] This appeal concerns a claim for a treatment injury by damage to the appellant's sciatic nerve, or his posterior femoral cutaneous nerve, in the course of a surgical procedure. [2] Mr Holden had suffered increasing and eventually very severe pain in his left leg and foot since 1995. His condition was associated with the development of fibrous tissue around his sciatic nerve. An exploratory procedure was done in 2000 but the pain continued. By 2005, the pain had progressed to a point that further surgery was considered and the surgical excision of scar tissue was done. [3] That treatment produced some short term relief, but once again the pain became worse. Mr Holden had surgery on the fibrosed nerve area again in 2009. That procedure was carried out in London. The operation note recorded that the posterior femoral nerve was found partially cut. The appellant says that the nerve must have been partially cut in the surgery in 2005, but in any case, whether cut in 2005 or in 2009, it was not a necessary part or ordinary consequence of treatment and was a treatment injury. [4] The evidence shows that cutting the nerve was not a necessary part of surgery, but it may have been an ordinary consequence, in view of the difficulty in separating the sciatic and posterior cutaneous nerves from surrounding scar tissue. Background [5] In June 2000 an MRI of Mr Holden's pelvis revealed a 1 cm focal mass present on the left sciatic nerve at the sciatic notch. The MRI report noted that the lesion may well be the cause of his pain. Neurologist Dr Stuart Mossman referred Mr Holden to consultant neurosurgeon Mr V Bala Krishnan. The referral described Mr Holden's symptoms of left leg pain dating since 1995 and increasing in severity over time. The pain was focused in the inner left buttock and the centre of the left leg and had recently extended into the anogenital area. Mr Bala Krishnan confirmed that the pain had become very severe. After discussing MRI films with the radiologist and with Mr Peter Johnston, general surgeon, Mr Bala Krishnan gave the opinion that Mr Holden had a lesion in the left sciatic nerve in the sciatic notch on the left side. It was not clear whether this was a cystic neurofibromatosisn pressing on the sciatic nerve. Explorative surgery was recommended. [6] On 14 August 2000, Mr Johnston and Mr Bala Krishnan performed exploratory surgery to Mr Holden's left sciatic nerve. The discharge summary recorded: "... exploration of left sciatic nerve was performed. There was no tumour found on the nerve, however a solid lump was felt close to the ischial spine and two pieces of well encapsulated tumour could be removed which appears to be arising from some of the nerves or muscle fibres. Histology: leiomyoma. No malignancy seen." [7] A leiomyoma is a benign growth arising from the muscle and not from the nerve. Mr Bala Krishnan reported that the tumour had been totally excised and recurrence would be unlikely. He continued to review Mr Holden post-operatively. Mr Holden was free of symptoms for a short time, and then began experiencing tightness of the gluteal muscle, tight hamstring, and pain over the scar. He also developed groin pain, and symptoms down the left leg and foot. Several MRI scans from 2001 to 2003 showed no evidence of tumour recurrence. A number of pain interventions and treatments were tried. [8] Mr Holden was concerned that he might end up in a wheelchair. He was advised by Mr Stuart Mossman, neurologist, that he was experiencing spontaneous electrical discharges from a nerve and sensitivity with an ongoing pain problem which may not resolve. He continued with various forms of treatment, including a number of analgesics, opiates, Kenacort injections, and use of a TENS machine but continued to experience symptoms, which were becoming progressively more severe. [9] In May 2004 Mr Martin Hunn, neurosurgeon, saw Mr Holden who was then keen on a re-exploration of the nerve. Mr Hunn explained the uncertain outcome of re-exploration and the risk of damage to the sciatic nerve leading to worse pain or functional loss. [10] An MRI in June 2004 showed no apparent mass but evidence of some post surgical fibrosis in the area where the sciatic nerve complex passes out through the sciatic notch in the region of previous surgery. [11] In November 2004, Mr Bala Krishnan advised: "Leiomyoma is a general surgical problem. I am not sure how easy it would be to re-explore the area turning a very large gluteal flap and this is likely to exacerbate his previous symptoms of pain in the keloid scar. Further exploration is likely to produce more fibrosis around the sciatic nerve and we may not be able to achieve any useful outcome by re-exploring a small area which is surrounded by too many small structures and muscles. However, I will discuss this option with Mr Johnston in the next few days." [12] An MRI in January 2005 showed the appearance of possible recurrence of the leiomyoma in the region of the sciatic notch. Mr Bala Krishnan then referred Mr Holden to Mr Johnston to manage the leiomyoma which appeared to be in close proximation with the sciatic nerve, and possibly the reason for recurrence of severe pain symptoms. Mr Johnston reported: "I can see the abnormality referred to in the MRI report and need to spend further time looking at this to clarify the anatomical structures but it would appear to be in a similar position to the leiomyoma excised at his previous operation about five years ago. In retrospect this abnormality can be seen in a subtle form in the previous scan which was in June 2004. It would appear at this stage to be reasonable to re-explore this area, but I need to give this thought and, in particular, consider what approach one might use. [13] Mr Johnston advised that Mr Holden would have to accept that there was no guarantee of improvement and there was a chance of loss of sciatic nerve function, either temporary or permanent. Mr Johnson reported in February 2005 that Mr Holden's pain syndrome seemed to be fairly specific to the sciatic nerve distribution. He thought that it would be reasonable to explore the nerve again and at least attempt to separate it from the fibrous tissue and remove any recurrence of the tumour which might be there. The concern that Mr Johnson expressed was about possible weakness in the leg from damage to the sciatic nerve. In a letter to the appellant's employer he stated that the prognosis was unclear and there was no guarantee that the proposed operation would resolve the issue, but hoped that there would be significant improvement. [14] Mr Johnston performed further exploratory surgery on 14 March 2005. He did not find a recurrence of the leiomyoma but did remove some dense scar tissue. Mr Johnston's handwritten note of the surgery recorded: "Operation: Exploration and neurolysis L sciatic nerve. Findings: dense fibrosis around the 4 cm of sciatic nerve immediately inferior to piriformis muscle. No mass lesion associated with the nerve could be found. Procedure: Henry question mark incision, 'stem' opened first, posterior femoral cutaneous nerve and sciatic identified below gluteus maximus, which was then divided laterally around the curve of the old incision. The sciatic nerve was then readily exposed to a level well deep to piriformis, at the entry of the sacral trunk. Nerve freed throughout the length of exposure, and then as much scar tissue as possible was excised from the nerve trunks themselves, making longitudinal cuts in the line of the nerve bundles. Good haemostasis." [15] The operation note did not refer to any suspected cutting of the posterior femoral nerve in the course of the procedure. Mr Johnston reported on 11 April 2005 that the character of the pain seemed to have changed. It was now more of a burning pain and could be compatible with the distribution of the posterior cutaneous nerve of the thigh which was in the operative field and was dissected free. He stated that the sciatic nerve was dissected free from well below the previous operative field through an area of scar tissue which was moderately dense at one point to reach the trunks of origin of the sciatic nerve. The nerve was intact and lying completely free at the end of this. There was no sign of recurrence of the leiomyoma. [16] Mr Holden was referred to the Burwood Pain Management Centre to consider a spinal cord stimulation implication for his chronic pain. In the referral letter, Mr Johnston noted that he had exposed the sciatic nerve from its origin from major nerve trunks deep to the piriformis muscle to below the buttock crease and, apart from moderate fibrosis at the site of the previous surgery, which was quite dense around the nerve at one point, he could not find any other lesion. [17] Spinal cord stimulation was attempted over a period of time but it only provided short-term improvements. [18] Mr Holden travelled to England in 2008. He was assessed in London by Professor P Anand, neurologist, and Mr Marco Sinisi, consultant peripheral nerve surgeon. Dr Sinisi considered surgical exploration of the origin of the posterior cutaneous nerve of the thigh may be of benefit. [19] On 22 October 2008 Mr Holden underwent exploratory surgery of the posterior cutaneous nerve with Mr Sinisi at the Royal National Orthopaedic Hospital in Stanmore. The operation note recorded: "Operation: Exploration, decompression of sciatic nerve and section of posterior cutaneous nerve of thigh. Pre-operatively: Patient affected by neuropathic pain due to possible partial lesion of the posterior cutaneous nerve of the thigh and compression of the sciatic nerve. Symptoms started after operation for removal of not better specified tumour. The pain is 8-9 out of 10 in intensity and this is with taking Oxynorm and other drugs for neuropathic pain. It is now 8 years that pain has-been affecting his life. . .. Procedure: Sciatic nerve is decompressed after being found completely surrounded by very intense fibrotic tissue for a length of about 15 cms. The posterior cutaneous nerve of the thigh is instead found partially cut and therefore decision to cut the nerve proximally at the site of the damage and bury it into the muscle is taken." [20] Dr Sinisi advised in January 2009 that the sciatic nerve had been quite stuck in scar tissue. He wrote: "The sciatic nerve was quite stuck in scar tissue and had lost its gliding capacity in the buttock area, but the most severe injury was found to be on the posterior cutaneous nerve of the thigh, which was partially damaged. This partial lesion was thought to be the 'trigger' of most of his symptoms both pre and intra operatively." [21] A treatment injury claim was lodged with ACC on 18 February 2009 for the damaged sciatic nerve from the surgery performed on 14 March 2005 by Mr Johnston. There is no evidence of damage caused to the sciatic nerve caused by treatment. The evidence bears upon damage to the posterior femoral cutaneous nerve and the claim was considered on that basis. [22] ACC asked Mr Johnston for a response. He wrote on 20 April 2009, noting that he had advised Mr Holden that there was a chance that some nerve function would be lost. He continued: "Without knowing the present situation, all I can comment is that ongoing pain would be part of the underlying process (i.e. scarring around nerves and alteration of pain pathways in the spinal cord and brain) and not necessarily a complication of the 2005 (or 2000) surgery: it was made clear to Mr Holden that the surgery might not change the pain. Loss of function in the sciatic and posterior cutaneous nerves, if detected on clinical examination or specific testing, could well be secondary to the 2005 surgery, and whether this is a treatment injury would be a matter of interpretation for ACC. You ask for my own view, which would be that partial loss of function in these nerves could be seen as either a 'necessary part' or 'ordinary consequence, probably the latter, given that it is very difficult to operate on scarred nerves without some nerve fibres being lost. Total loss of the sciatic or posterior cutaneous nerves might be fairly seen as beyond necessary part or ordinary consequence." [23] Mr Johnston wrote again on 21 July 2009 as follows: "I note that the preoperative review by the neurologist Prof Anand found heat hypersensitivity in the expected distribution of the posterior femoral cutaneous nerve; if this nerve had been severed previously one might have expected an area of sensory loss on the posterior leg as this nerve typically supplies quite a large area of skin. However, given the length of time involved, it is also possible than ingrowth of nerve fibres from other nerves could have occurred and made such a deficit no longer obvious. At surgery on nerves embedded in scar tissue it would be difficult to be sure if a defect in the nerve resulted from previous surgery or was just the result of removing scar tissue to expose it at the 2008 operation. At any rate, I would still be inclined to regard loss or partial loss of this nerve as 'necessary part' or more likely 'ordinary consequence' than an unexpected or unpredictable consequence of surgery. As noted in my previous report, some loss of function in this nerve was discussed prior to the 2005 operation, and could have been inevitable in spite of the most careful technique. The pathological process ('underlying health condition') of scar formation around nerves was the most important component of the outcome here. [24] Mr Holden was also treated by Dr Nanda Bellum, pain management specialist, from 2003 to 2005. ACC asked for an opinion from Dr Bellum who reported in April 2009 that neuropathic pain following surgery is a rare complication and is not necessarily a part or consequence of treatment. The appellant relies in part on that evidence, that his pain was not an ordinary consequence of surgery. Oddly, Dr Bellum also wrote that "Treatment is not the cause of pain or injury, neuropathic pain is one of the rare complications specially when surgery involves close to the nerves". His comment that treatment is not the cause possibly meant that it is not an inevitable cause. [25] Dr Chris Moughan, ACC medical advisor, prepared a file review in July 2009. After reviewing the relevant medial records, he outlined the focus of the enquiry as follows: "With neuropathic pain following surgery, the difficulty is that from a legal perspective, in accordance with case law, neuropathic pain (secondary to alteration of pain pathways in the spinal cord and brain); does not-constitute a physical injury for ACC purposes. (Teen and other cases) And scarring around nerves secondary to dissection is regarded as an ordinary body response - not eligible for cover as a treatment injury. However, neuropathic pain resulting from other personal injury (that is physical injury) may be acceptable for cover. The difficulty in this and similar cases is identifying personal injury caused by treatment where necessary treatment has been properly given. Onset of neuropathic pain may occur as a result of surgery. Surgical incision represents physical injury to the person (personal injury) however, as a necessary part of the treatment, the incision is not eligible as for cover as personal injury caused by treatment. Moreover, if the incision has not been identified as the cause of any other discrete physical injury that has resulted in pain syndrome, then no discrete injury can be identified. To be clear, if there is not evidence that a particular nerve was cut, or a particular structure was damaged beyond the incision, then no discrete injury can be identified (putting aside the incision etc required for the procedure). [26] That is a correct summary of the medico legal issues, but it does not go one step further to identify the medical question whether accidental cutting of a posterior femoral nerve was an ordinary consequence of treatment. The incisions and cutting away scar tissue, if correctly done, were a necessary part of treatment and excluded from treatment injury. Unintended cutting of the posterior femoral nerve would not have been a necessary part of treatment, but could have been an ordinary consequence if the procedure was so delicate that partial cutting of a nerve could well occur. The respondent also submits that there is little evidence that the nerve was cut during surgery in 2005. However, in his report Dr Moughan wrote: "The new information from Professor Johnson does not confirm damage to the nerve other than might have been expected. He explains that it would be difficult to be sure if a defect in the nerve resulted from the previous surgery in 2005 - or was just the result of removing scar tissue to expose the nerve at the 2008 operation overseas. Hence, having obtained the 2008 operation findings, 'partial cutting' of the posterior cutaneous nerve of the thigh in relation to treatment in 2005 cannot be confirmed. Whether the findings at exploration in 2008 were indicative of 'partial cutting' injury in 2005 or simply found in relation to re-exploration with re-division of adhesions, would be speculative. Hence it appears unlikely that further opinion could change this conclusion. However, it is accepted that the nerve may have necessarily been injured to some extent as part of the dissection in 2005 - in order to separate the nerve from its adhesions, the extent of injury being a necessary part or at least an ordinary consequence of the required dissection, even with the most careful technique. The operating surgeon is in a unique position to comment on this, as every case may differ according to the amount of scar tissue present etc - and the operator can really only know in detail what was found and what was required and intended in dealing with these findings at the time of treatment. The underlying ordinary healing process of scar formation around nerves remains the most important component of the outcome. [27] Dr Moughan was aware of the "ordinary consequences" exception. considered that if the nerve was injured as part of the dissection in 2005, then it was a necessary part or an ordinary consequence of the procedure in order to separate the nerve from its adhesion. Concerning the London Hospital operation note that "The posterior cutaneous nerve of the thigh is instead found partially cut", he advised ACC that it would be difficult to determine whether the findings at the 2008 surgery indicated a "partial cutting" injury from the 2005 surgery "or simply found in relation to re-exploration with re-division of adhesions". He noted Mr Johnston's comment that "At surgery on nerves embedded in scar tissue it would be difficult to be sure if a defect in the nerve resulted from previous surgery or was just the result of removing scar tissue to expose it at the 2008 operation". [28] On 6 August 2009, ACC issued a decision to decline Mr Holden's treatment injury claim. The decision was accompanied by a summary of reasons, with the conclusion: "ACC accepts that the nerve may have necessarily been injured to some extent as part of the dissection in 2005 in order to separate the nerve from its adhesions, the extent of injury being a necessary part or at least an ordinary consequence of the required dissection, even with the most careful technique. The operating surgeon is in a unique position to comment on this, as every case may differ." [29] Mr Holden applied for a review which was heard by Mr Peter Barker on 3 November 2010. In his written decision dismissing the application, the Reviewer noted: "The evidence supports, on the balance of probabilities, that Mr Holden sustained damage to his nerves in the surgery in 2005. Specifically, damage to the sciatic and posterior cutaneous nerves. The issue is whether that injury occurred in circumstances that meet the criteria for treatment injury under Section 32 of the Act. In Mr Holden's case Mr Johnson has advised that the surgery in 2005 removed scar tissue from the nerves and made longitudinal cuts to the nerves. Clearly this was in response to what he found during the operation. Mr Johnson has not indicated that he did anything during the operation that he did not expect to. He freed the nerves and removed scar tissue. The resulting injury, being damage to the nerves, is a necessary part of the incision made to perform that treatment. As such I find that it must fall into the exclusionary provision of a necessary or ordinary consequence of that treatment." [30] Finally, Mr Johnston wrote again on 27 June 2011 in reply to questions from counsel for the respondent. He explained the purpose of longitudinal cuts in the line of nerve bundles involved in scar tissue to attempt to release the constriction with little damage to nerve fibres. He commented that he had not recorded any partial severing of the nerve at the time of the operation, and noted that Professor Anand, the neurologist who examined Mr Holden in London, did not record a sensory deficit in the distribution of the nerve, but noted hypersensitivity to heat. According to Mr Johnston that suggested compression of the nerve, and that the nerve was intact. Separation of nerves from scar tissue is at times very difficult, and Mr Holden's London operation would have been his third through this site. Mr Johnston said that it is not impossible that the partial severing of the posterior cutaneous nerve actually happened during the process of opening up the old scars during the London operation, rather than at the 2005 operation. Concerning the change of cutting the nerve in 2005, he wrote: "Reading from my preoperative letters in 2005, I focused on the possibility of damage to the sciatic nerve, as that may lead to motor loss, which is more of a problem than sensory loss alone (as would be suffered by damage to the posterior femoral cutaneous nerve). A likelihood of about 20% of nerve loss of some kind would have been in my mind when writing these letters, and I am pretty sure I would have put that sort of incidence directly to Mr Holden. I can add that there are no certainties in this sort of surgery, and that if the posterior femoral cutaneous nerve was partly divided at the 2005 operation, it is not necessarily the case that this was responsible for his ongoing pain problem, which was relatively longstanding by that time. I do not know of his present situation, and whether the London operation actually helped him other than in the short term." [31] Dr Johnston did not refer back to his own comment in 2005 that a burning pain, a different sensation following the operation, could be compatible with the distribution of the posterior cutaneous nerve. [32] For completeness, the relevant parts of the treatment injury definition are as follows: 32 Treatment injury (1) Treatment injury means personal injury that is - (a) suffered by a person - (i) seeking treatment from 1 or more registered health professionals; or (ii) receiving treatment from, or at the direction of, 1 or more registered health professionals; or (iii) referred to in subsection (7); and (b) caused by treatment; and (c) not a necessary part, or ordinary consequence, of the treatment, taking into account all the circumstances of the treatment, including - (i) the person's underlying health condition at the time of the treatment; and (ii) the clinical knowledge at the time of the treatment. (2) Treatment injury does not include the following kinds of personal injury: (a) personal injury that is wholly or substantially caused by a person's underlying health condition: Submissions [33] It is common ground that the dissection of fibrous tissue was necessary in 2005 because of the appellant's underlying health condition. The scarring was a relevant health condition to be taken into account when deciding whether the treatment was conducted with proper care but nevertheless caused damage to a nerve. [34] Ms Lau for the appellant submitted that Mr Holden had no symptoms that related to the posterior cutaneous nerve of the thigh before the 2005 surgery. Mr Johnson had reported on 17 January 2005 that the distribution of Mr Holden's pain is compatible with sciatic nerve compression. He reported on 14 February 2005 that the appellant's pain syndrome seemed to be fairly specific to the sciatic nerve distribution. But after the 2005 surgery, Mr Johnson reported on 11 April 2005 that the character of the appellant's pain changed following surgery and could be compatible with the distribution of the posterior cutaneous nerve of the thigh. That was consistent with pain treatment reports during 2005. [35] When Dr Sinisi operated on Mr Holden in 2008, he reported in the operation note that the posterior cutaneous nerve of the thigh was "found partially cut". Ms Lau submitted that Dr Sinisi must have intended to describe the state of the nerve as it was found. Overall, it was submitted that the evidence points to the probability that the nerve was accidentally cut during the 2005 surgery. Dr Moughan reported on 5 August 2008 that "it is accepted that the nerve may have necessarily been injured to some extent as part of the dissection in 2005". The Reviewer Mr Barker also found that the "evidence supports, on the balance of probabilities, that Mr Holden sustained damage to his nerves in the surgery in 2005". [36] Ms Lau submitted submitted that damage to the nerves is not a necessary part of the treatment. That is not really in issue in this case. It was not a necessary part of the treatment, the question is whether it was an ordinary consequence of the treatment. [37] Ms Lau referred to Dr Bellum's comment in his letter in April 2009 that "neuropathic pain is one of the rare complications specially when surgery involves close to the nerves". She submitted that neuropathic pain arising from damage to the nerve would be even rarer, as nerve damage would be only one of the possible causes of neuropathic pain. It is an exceptional and unusual complication of the treatment, and not an ordinary consequence. She submitted that Mr Johnston did not realistically anticipate that the appellant would be in a worse condition post surgery than pre surgery. Although there was no guarantee that the proposed operation would resolve the issue, he hoped that there would be significant improvement. He warned that there was a chance of some loss of sciatic nerve function, but he did not indicate that loss of function in the posterior cutaneous nerve of the thigh would be an expected outcome. [38] Ms Lau referred to an observation by Judge Cadenhead in McEnteer v ACC [2008] NZACC 105 "parliament has done away with the concepts of fault and severe and rare consequences of treatment" and that the amendment to the law from medical misadventure to treatment injury "was designed to be more beneficial to claimants". Ms Lau also referred to authority that damage of a unusual and severe kind may be covered as a treatment injury even though less damage would have been within the expected range. The appellant has submitted that the actual cutting was damage of a severe kind that exceeded any ordinary consequence of damage that might have been expected. [39] Ms Miller for the respondent submitted that Mr Johnston's opinion and advice of 27 June 2011 was uncontradicted when he advised that separation of nerves from scar tissue is at times very difficult and it was not impossible that severing of the posterior cutaneous nerve actually happened during the process of opening up the old scars during the London operation. Mr Johnston had not recorded any cutting of the posterior cutaneous nerve in 2005 and was not aware that any had occurred, but in view of the inherent difficulty of the procedure it was possible. In fact a likelihood of about 20% of nerve loss of some kind would have been predictable. [40] It was submitted that the Court must consider Mr Holden's injury in light of his particular circumstances. The relevant circumstances in Mr Holden's case are that his surgeries have been exploratory and in response to his persistent and intractable pain of an unknown origin. Mr Sinisi described the 2008 surgery as an exploration of the sciatic and posterior cutaneous nerve. It is clear from the evidence that nerve damage was a recognised risk of exploratory surgery. Mr Johnston explained that, before the 2005 surgery, that he focused on sciatic nerve damage rather than posterior cutaneous nerve damage because sciatic damage could lead to motor loss, but there was a likelihood of about 20% of nerve loss of some kind. In such exacting surgery separating the sciatic nerve from dense scar tissue, damage to a nerve was a real likelihood. [41] It was submitted that the whole of the operative process in 2005 was a necessary part of the procedure to free the sciatic nerve from fibrosed tissue. The respondent accepted that the posterior cutaneous nerve may have been damaged to some extent as a result of treatment, but there is only speculative evidence as to when the posterior cutaneous nerve was damaged. A "possibility" that it occurred during the 2005 surgery is insufficient and it was more likely than not to have occurred during surgery in London in 2008. [42] Ms Miller submitted that the evidence of change in Mr Holden's symptoms after the 2005 procedure is inconclusive. His symptoms had always been unusual and have never been entirely explained. He had a myriad of pain symptoms, increasing in severity since 1995. He had sensory loss and pain that was outside of the sacral nerve distribution and was not explained by the leiomyoma. His pain is reported to have continued since his 2008 surgery, albeit to a lesser extent, despite Mr Sinisi completely severing the posterior cutaneous nerve and burying it in muscle. [43] Ms Miller referred to in ACC v Porter [2010] NZACC 104, in which Judge Barber in this Court rejected a Reviewer's finding that "ordinary" is something "regular" or "usual" and that a "complication" could not be seen as regular or ordinary consequence of surgery. Judge Barber said: [42] It is put for ACC that, first, the words "ordinary consequence" are not used in the Act in such a way as to be interchangeable with "regular" or "usual" as in a "regular consequence" or "usual consequence". I can accept that distinction. Second, concentration on the words alone, without reference to the rest of the subsection, deflects attention from the need to link the interpretation of the words, and the requirement that all of the circumstances of the treatment be taken into account, with specific emphasis on a person's underlying health condition and the state of clinical knowledge at the time of the treatment. That seems a valid approach. [43] I can accept that comparing the words of s 32(1)(c) in the way the Reviewer did might suggest a kind of probability analysis where consequence X is more or less likely from treatment Y. However, a percentage assessment is not required, nor is it appropriate to make a probability assessment of the kind which applied under the previous medical misadventure/medical mishap provisions. [44] I agree with Mr Hunt that the necessary evaluation is whether the injury is an ordinary consequence having regard to all of the circumstances of his treatment, i.e. any relevant circumstance can be taken into account. Mandatory consideration is to be given to the person's underlying health condition and the state of clinical knowledge at the time of treatment. Discussion [44] The primary meaning of a "necessary part of treatment", is a part of the treatment process done deliberately for medical reasons. The evidence does not suggest that a nerve was cut deliberately. An "ordinary consequence" encompasses unintended consequences or side effects that are expected to occur in numbers of cases. Consequences that are rare would not be ordinary consequences, but there will inevitably be a range of consequences that are more difficult to classify. [45] The surgery in 2005 involved dissecting nerves from scar tissue. Mr Johnston stated that it is very difficult to operate on scarred nerves without some nerve fibres being lost. There is no challenge to that evidence. Mr Johnston's 2005 operation note did not mention any accidental cutting of the posterior cutaneous nerve, but he acknowledged that some loss of function of the sciatic nerve and posterior femoral nerve could well be secondary to the 2005 surgery. He considered partial loss of the nerve, or partial loss of nerve function, as a "necessary part" or more likely "ordinary consequence" than an unexpected or unpredictable consequence of surgery. No doubt he was reluctant to comment on the alleged cutting of the nerve because he had not been aware that the nerve was cut in the 2005 operation, and he had not seen the condition of the nerve described by Dr Sinisi. [46] I agree with the Reviewer's conclusion that it is probable that some damage occurred to the posterior femoral cutaneous nerve during the 2005 procedure. The visual evidence of Dr Sinisi was supported by a change in the appellant's pain symptoms after the 2005 operation, consistent with damage to the posterior femoral nerve. [47] The important question is whether the nerve damage was an ordinary consequence of surgery that involved dissecting the nerve from surrounding scar tissue. The extent of the scar tissue was described in 2005 as "dense fibrosis around the 4 cm of sciatic nerve" and in 2008 as "very intense fibrotic tissue for a length of about 15 cms" of the sciatic nerve. The evidence shows that the posterior femoral cutaneous nerve was in the operative area of dissecting of the sciatic nerve from surrounding scar tissue. [48] I am satisfied from the evidence that damage to either the sciatic nerve or the posterior femoral nerve was a real possibility when dissecting the sciatic nerve from scar tissue. There is no medical evidence to the contrary. Mr Johnston advised the appellant, before surgery in 2005, that there was a chance of loss of sciatic nerve function. It was a real chance and not a remote chance. The evidence shows that the comment could be applied equally to possible loss of posterior cutaneous nerve function. At the time, the sciatic nerve was specifically considered because it was the nerve affected by scarring, and also that damage could affect the appellant's mobility. The evidence does not clearly explain how proximate the posterior femoral nerve was to the area of dissection, but it was in the operative field and there is no evidence that it should have been safe from damage in a properly conducted procedure to free the sciatic nerve. [49] The outcome for the appellant was very unfortunate. His symptoms were mainly associated with the scarring which was an underlying condition, to some extent aggravated by necessary surgical intervention. The surgical intervention itself is not a subject of a treatment injury claim, only the damage to the posterior femoral nerve. [50] There is no certainty that ongoing symptoms are directly attributable to cutting of the posterior femoral nerve seen by Dr Sinisi. However the cutting was an injury, whether or not it was the major cause of new symptoms. [51] The appellant has submitted that the actual cutting was damage of a severe kind that exceeded any ordinary consequence of damage that might have been expected. There is however insufficient evidence that the damage was severe to a degree beyond ordinary consequences of the appellant's surgery. Dr Sinisi was not asked to provide a detailed opinion concerning the extent of damage to the nerve, the likelihood of that damage occurring in carefully conducted surgery in 2005, or the possibility of the damage having occurred during his own surgery. [52] On the evidence presented, I find that damage to nerves in the operative field, including the posterior femoral cutaneous nerve, was in the range of expected consequences of surgery. It was not a rare or unexpected complication but was an ordinary consequence. Dr Bellum's opinion to that effect was not expressed clearly and is not consistent with the overall evidence. Damage to the posterior femoral cutaneous nerve was not inevitable, but was a clear possibility. [53] For those reasons, the appeal is dismissed. E Judge D A Ongley District Court Judge