Insurance Australia Limited t/as NRMA Insurance v Seadon

DETERMINATION OF REVIEW PANEL
CITATION:	Insurance Australia Limited t/as NRMA Insurance v Seadon [2023] NSWPICMP 181
CLAIMANT:	Kerry Seadon
INSURER:	Insurance Australia Limited t/as NRMA Insurance
REVIEW Panel
MEMBER:	Alexander Bolton
MEDICAL ASSESSOR:	Paul Curtin
MEDICAL ASSESSOR:	Tai-Tak Wan
DATE OF DECISION:	4 May 2023
CATCHWORDS:	MOTOR ACCIDENTS – Review on the application of the insurer of certificate of Medical Assessor McGlynn who assessed whole person impairment (WPI) at 16%; claimant injured in pushbike versus car accident on 2 January 2016; insured car turned right across the path of the claimant with the claimant and her bike going across the bonnet of the car and landing on the road; ambulance and police did not attend accident; claimant attended General Practitioner the day after the accident; claimant had previous injury to her jaw in 2006 but had not sought treatment for that injury since 2009; prior to the accident the claimant had no issues with mastication; claimant suffered anterior subluxation of her temporomandibular joint meniscus on the right side and hypermobility of the condyle of the right side; claimant developed ongoing jaw pain and ultimately had an arthrocentesis of the right temporomandibular joint and then removal of the meniscus and replacement with a fat graft and subsequently a total joint replacement with a metal implant; claimant still has ongoing jaw pain; restricted diet due to inability to masticate fully and need for soft foods; insurer submitted that the claimant’s disabilities were attributable to the earlier accident in 2006 and denied causation; Held – Panel was satisfied that the claimant’s injuries were attributable to the accident occurring on 2 January 2016 and WPI assessed at 22% following medical examination.
DETERMINATIONS MADE:	CERTIFICATE OF DETERMINATION Determination 1. The Panel revokes the Certificate of Medical Assessor McGlynn dated 21 February 2022. 2. The Panel finds that the injuries suffered by the claimant in the accident on 2 January 2016 are causally related. 3. The Panel finds a total whole person impairment of 22%.

BACKGROUND

This is an application by the insurer to review the decision of Medical Assessor McGlynn (the assessor) dated 21 February 2022.
The assessor found that the injury caused to the claimant's temporomandibular joint (TMJ) injury- soft tissue injury, gave rise to a 16% whole person impairment (WPI).

The accident and subsequent treatment

This is a claim arising out of an accident on 2 January 2016. The claimant was a cyclist who collided with the insured car when the driver of the car made a right hand turn across her path. The collision caused the claimant to travel across the car's bonnet and onto the road.
Following the accident, ambulance officers did not attend. The claimant did not go to hospital. The accident occurred late in the day. She went home and saw her general medical practitioner the following day. Initial treatment was physiotherapy, anti-inflammatory medication and analgesics with avoidance of chewing.
The jaw pain persisted. The claimant saw Dr Finkelstein, on 7 February 2016. He referred her to Dr Lydia Lim, oral and maxillofacial surgeon. Dr Lim has undertaken multiple surgical treatments:
a)    29 July 2016 – arthrocentesis right TMJ;
b)    31 July 2017 – right TMJ arthroscopy;
c)    12 July 2018 - right TMJ arthroplasty-discectomy and abdominal fat graft to joint, and
d)    13 August 2018 - insertion of replacement right TMJ joint
In July 2019 Ms Seadon was referred to Smileteam Orthodontics for limited jaw opening and malocclusion management. A treatment plan was recommended but was not done.

Earlier accident

In 2006 the claimant sustained injuries in another motor vehicle accident. She was cycling and collided with a car when a door opened across her path. She sustained a neck injury and developed right side jaw pain. The claimant was seen by
Dr Bosanquet, a Wollongong dental surgeon and her jaw pain improved with physiotherapy and dental splinting. Ms Seadon informed Assessor McGlynn that the right face pain was completely resolved with the treatment program and she had no ongoing symptoms or disability.

Claimant's submissions

The claimant dealt with the submissions of the insurer that the claimant's TMJ problems were attributable to the accident in 2006.
The claimant said that the assessor acknowledged the prior injury to the claimant at various points in his Certificate. The claimant highlighted that on page 2 he noted:
"In 2006 she sustained injuries in a previous motor vehicle accident. She was cycling and collided with a motor vehicle door that opened across her path. She sustained a neck injury and developed right side jaw pain. She was seen by
Dr Bosanquet, a Wollongong dental surgeon and her jaw pain improved with physiotherapy and dental splinting. Ms Seadon stated the right face pain completely resolved with the treatment program and she had no ongoing symptoms or disability."
The claimant provided further reference to the Certificate of the assessor at page 5 where he provided a review of relevant pre-existing documentation as follows:
" ‘Medical Report Dr Nigel Curtis, oral & maxillofacial surgeon 12/12/2007 –
describes pushbike accident on 21/01/2006 with subsequent right-sided jaw pain. States OPG x-ray 8/03/2006 reported no abnormality; lateral TMJ x-rays
on 10/02/2006 indicated narrowing of the right TMJ and that may be indicative
of anterior displacement of the joint meniscus; MRI 28/07/2006 demonstrated
anterior displacement of right TMJ meniscus, plus some disruption of the
architecture of the meniscus. Diagnosis was right TMJ dysfunction which could
be managed with arthrocentesis followed by an occlusal splint. with the
prognosis for full recovery being good.’
…
Correspondence of Dr R D'Rosario, dental surgeon 16/06/2009 – ‘Kerry's
history of her symptoms, and her clinical findings on examination, are
consistent with an internal derangement in the right temporomandibular joint.
This was confirmed on a subsequent MRI scan of the temporomandibular joints
dated 18 May 2009 which revealed a subtle anteriorly displaced disc in the right
temporomandibular joint with reduction.’
Recommended conservative treatment with physiotherapy."
The claimant further submitted that on page 7 of the assessor's Certificate, having considered the above, the assessor provided his reasoning as follows:
"There is evidence in the documents seen of pre-existing right TMJ injury/condition caused by a motor vehicle accident in 2006. There is no objective evidence of symptomatic permanent impairment from this injury at the time of the subject motor vehicle accident on 2/02/2016. Kerry Seadon stated she was pain-free and had no restriction of mastication at the time of this second accident. As there is no objective evidence of the pre-existing symptomatic permanent impairment, its possible presence should be ignored and no deduction made for the previous injury that on the evidence fully resolved."
The claimant submitted that the insurer's submission that the treatment received by
Dr Lydia Lim is inappropriate is irrelevant to the review application. The claimant says that what is relevant is whether the claimant developed right temporomandibular joint pain because of the accident.
The claimant submits that the insurer appears to raise causation as an issue in its submissions which would run counter to Dr Curtis' assessment of 10% WPI and his opinion on page 5 of his report of 12 February 2019 that:
"I do note that Ms Seadon did suffer injuries over the right side of her body to the right shoulder, knee and neck region. This is consistent with a possible injury to the right temporomandibular joint during the accident. In motor vehicle accidents of this form of injury a flexion extension or whiplash injury of the neck is suffered to the jaw joint causing distraction of the joint meniscus resulting in the mentioned internal derangement of the temporomandibular joint."
The claimant submitted that the assessor agreed with Dr Curtis' level of impairment for restricted mastication. This was compared to the assessment of Dr David, which the assessor considered excessive. The assessor mentions on page 6 that Dr Curtis “has not described what pre-existing dysfunction was present and why it caused the 5% WPI deduction”.
The claimant says that the assessor's medical assessment of the claimant is not incorrect in a material respect, and the insurer's application for review should fail.

Insurer's submissions

The insurer submits that in the course of providing his determination, the assessor failed to address the central issue raised by the insurer's submissions and provide sufficient reasoning in support of a decision that resolves the subject issue.
The insurer submits that it provided articulated submissions which argued that the claimant did not sustain any permanent injury to her TMJ due to the accident and that the subject accident did not give rise to any assessable permanent impairment.
The insurer said that this submission limits the insurer's liability regarding the claimant's TMJ to the temporary injuries which result from the subject accident, as it is maintained that these injuries do not result in any assessable permanent impairment.
While the insurer said that it is accepted that Assessor McGlynn acknowledged this submission on page 2 of his Certificate, the insurer highlights that there are no further references to the temporary nature of the soft-tissue injuries submitted by the insurer to be sustained in the subject accident.
The insurer referred to the reports of both Professor David and Dr Curtis and highlighted the following:
(a) Dr Curtis said in his supplementary report (A3) that "…the insurance company should be generally a little more careful and circumspect in approving end stage joint replacement surgery which generates large surgical fees but can commonly result in intractable poor results as in this case", and
(b) Professor David said in his report (A4) that "with respect to her right temporomandibular joint pain and dysfunction, Ms Seadon has disabilities of mastication and deglutition, altered facial appearance and a resulting speech defect". The right temporomandibular joint is noted to be the location of the surgeries performed by Dr Lim.
The insurer referred to the opinions of Professor David and Dr Curtis. It noted that these assessments were related to injuries caused by the surgeries performed by
Dr Lim, which the insurer says were not approved by it.
The insurer says that on both pages 1 and 2 of its initial submissions, clear references are provided to the opinions of both Dr Curtis and Professor David, which demonstrate that the mastication and facial disfigurement injuries are caused by the string of surgeries performed on the claimant's TMJ by Dr Lim.
The insurer says that Assessor McGlynn, on pages 6 and 7 of his report, determines that the WPI arising from the right temporomandibular joint injury is assessed at 16% due to mastication and facial disfigurement arising from the skeletal deformity. The insurer submits that the reasons provided by Assessor McGlynn, in his commentary and determination, demonstrate that his assessment was based on injuries which arose from the surgeries performed by Dr Lim and not the temporary injuries submitted by the insurer to arise from the subject accident.
The insurer says that by failing to address the insurer's submissions, Assessor McGlynn has failed to identify whether the cause of the claimant's symptoms was an accident-related pathological change or due to the surgery, which the insurer has maintained, is not related to the subject accident.
The insurer submits that the assessor's reasons do not correctly identify the central issue between the parties and, therefore, do not provide a correct determination or reasoning regarding the WPI attributable to the claimant's injuries arising from the subject accident.
The insurer, in its submissions, has referred to its initial submissions made in reply to the claimant's application for assessment of WPI.
The insurer submitted that any injury the claimant sustained as a result of the subject accident manifested as a temporary aggravation of a pre-existing condition, and the pre-existing condition was exacerbated by the unwarranted surgeries performed by
Dr Lim and Dr Bouloux.
The insurer otherwise submitted that any assessment of permanent impairment must make apportionment in respect of the claimant's pre-existing conditions and the effects of the claimant's post-accident injuries, treatments/unsuccessful surgeries and diagnoses.
The insurer submitted that the claimant did not sustain any permanent injury to her TMJ due to the accident, and the subject accident did not give rise to any assessable permanent impairment.
The insurer says that the claimant was involved in a prior motor accident in 2006 and was diagnosed with significant TMJ dysfunction.
The insurer says that the claimant required a referral to a jaw specialist (Dr D'Rosario) in 2009 for a locking jaw. She was attending her physiotherapist for treatment of the jaw in May 2009.
The insurer says that the claimant did not attend hospital following the subject accident. The insurer referred to the report of Dr Curtis, who said in his February 2019 report that "It does immediately appear a little strange that for a patient who did not attend nor was taken to a hospital following this accident that major surgery carried out by Dr Lim in this case would be either warranted or appropriate".
The insurer says that Dr Curtis said that:
“there are very limited genuine implications for full prosthetic joint replacement of the temporomandibular joint and these include major trauma and ankyloses of the joint. Neither of these conditions do appear to be applicable prior to joint replacement for Ms Seadon in this case.”
The insurer says that Dr Curtis said that “further open exploration and repair of the joint should have been gained before proceeding to joint replacement in this case”.
The insurer submitted that Dr Curtis said the MRI and CT performed on
8 November 2016 of the mandible demonstrated a degenerative change of the right condyle plus disc displacement.
The insurer noted that Dr Curtis said that it would have been more reasonable to defer end-stage surgery for a further six months and assess the need for a further joint exploration prior to consideration of joint replacement.
The insurer referred to the claimant relying on the opinion of Professor David, oral and maxillofacial surgeon. In addition, the insurer highlighted the following:
(a)    Professor David found a Class 2 facial disfigurement. The insurer submits that this classification is incorrect as the plaintiff has not suffered a fracture to her facial skeleton;
(b)    Professor David's classification of the table utilised references 'New South Wales Workers Compensation' Guidelines which is incorrect, and
(c)     concerning the reduction of mastication and deglutition, which Professor David describes a maximum 19% WIP, the insurer notes that this relates to the highest percentage achievable. The maximum 19% WPI attributable to reduced jaw movement would usually be relevant in cases of complete ankylosis or acute trauma to the jaw joint, which causes no jaw movement. The insurer notes that the claimant does not have this issue.

The insurer submits as follows:

Any injuries sustained by the claimant due to the subject accident consisted of a temporary aggravation of pre-existing conditions.
The claimant's current TMJ condition arose due to a pre-existing significant TMJ displacement exacerbated by the unwarranted surgeries performed by Dr Lim and
Dr Bouloux.
Should the assessor make any findings of permanent impairment, the insurer submits as follows:
(a) the assessor should deduct the claimant's pre-existing conditions from any assessment of WPI, and
(b) the assessor should make an apportionment to allow for the effects of the claimant's unwarranted and unsuccessful surgeries and deduct this from any assessment of WPI.

Medical reports

Regarding the assessment of Dr McGlynn, the claimant reported that her right facial pain had resolved following TMJ replacement surgery and was replaced with episodic severe headaches that are predominantly right sided. She said the headache started with discomfort in the right TMJ region and spread to her head.
The claimant is conscious of visible scarring from jaw surgery on the right side of her face and neck. Her right molar teeth do not make contact when she bites her teeth together.
At the time of examination, the claimant reported that her right facial pain had resolved following TMJ replacement surgery and had been replaced with severe episodic headaches that are predominantly right sided. She says the headache starts with discomfort in the right TMJ region and spreads to her head. In addition, she reported that her speech deteriorates when constantly speaking for a long time.
The assessor commented that there was visible asymmetry of her mid face, with the right side flatter than the left and the right angle of the mandible higher than the left. There was no soft tissue loss on the right side. The visible asymmetry was due to the skeletal asymmetry of the mandible.
There was visible surgical scarring on the right face preauricular region extending onto the right anterior neck, 110 mm x 2 mm, hypopigmented with noticeable colour contrast, slightly indented, with some barely visible stitch marks, no trophic features, and no adherence. There was a loss of sensation along the cheek scar.
Her mouth opened to only 18 mm between the anterior teeth. The chin moved to the right when opening was initiated, then back to the centre. There was no palpable or audible crepitus of either TMJ.
As to a permanent impairment assessment, the assessor calculated a right temporomandibular joint injury causing 16% WPI.
The assessor then discussed the following;
(a)   Mastication – Motor Accident Permanent Impairment Guidelines (MAA Guidelines) version 1, Effective from 5 October 1999 to the day before 1 December 2017, states:
“1.196 Where loss of structural integrity occurs as a result of a dental injury, the injury must be assessed for a loss of functional capacity (mastication) and a loss of structural integrity (cosmetic deformity) and any impairment combined.
1.197 When using Table 6' Relationship of dietary restrictions to permanent impairment' (page 231, AMA4 Guides), the first category is to be 0–19%, not 5–19%. AMA4 Table 6, page 231 allows for an impairment range of 0% to 19%WPI) if ‘diet is restricted to
semisolid or soft foods’.
The assessor said that the claimant had a restriction of diet to soft and semisolid food. He placed her condition in the middle of the range at 10%WPI, as her symptoms were reported as unilateral.
MAA Guidelines version 1 paragraph 1.31 states, 'If there is objective evidence of a pre-existing symptomatic permanent impairment in the same region at the time of the accident, then its value must be calculated and subtracted from the current WPI value. If there is no objective evidence of the pr- existing symptomatic permanent impairment, then its possible presence should be ignored’.”
The assessor said there was evidence in the documents of pre-existing right TMJ injury/condition caused by a motor vehicle accident in 2006. However, he said there was no objective evidence of symptomatic permanent impairment from this injury at the time of the subject motor vehicle accident on 2/02/2016. The assessor said that the claimant reported that she was pain-free and had no restriction of mastication at the time of this second accident. The assessor said that as there was no objective evidence of the pre-existing symptomatic permanent impairment, its possible presence should be ignored and no deduction made for the previous injury that, on the evidence, fully resolved.
(b)     Face - MAA Guidelines Version 1 (the guidelines) paragraphs 1.189-1.191 refer to facial scarring and disfigurement. The guidelines do not mention skeletal injury of the face. The Americal Medical Association Guides to the Evaluation of Permanent Impairment, 4^th Edition ( AMA4) Section 9.2. pages 229 & 230 deal with the face.
Damage to the facial bones causing deformity is Class 2 Facial Impairment with the range of 5%WPI- 10%WPI. On page 229 of AMA4, Class 2 Facial Impairment is described as a loss of supporting structure of part of the face, with or without a cutaneous disorder.
The assessor said that the claimant had facial deformity due to mandible asymmetry causing visible skeletal deformity, following resectioning the right mandible condyle and replacing the right TMJ. The skeletal deformity is Class 2 Facial Disfigurement. The visible facial scarring is included in Class 2. In my opinion there is 7% WPI to the facial disfigurement.
(c)     Speech - MAA Guidelines Version 1 paragraph 1.200 directs use of AMA4 for assessment of speech. The assessor found her speech audible, intelligible, and functionally efficient. He found no speech disability at this assessment. There was 0% WPI for this classification.
The multiple WPI (10%, 7% & 0%) combinations when using the Combined Values Chart of AMA4 amounted to 16%WPI.

Professor David examined the claimant on her behalf. He reported that the claimant had sustained a soft tissue injury to her right TMJ in the accident resulting in joint pain and dysfunction. He found impairment of mastication causing 19% WPI with a 2% deduction for pre-existing condition; Class 2 facial disfigurement due to facial nerve dysfunction and loss of structure following removal of the right TMJ causing 7% WPI; and speech distortion due to malocclusion with right-sided open bite and tongue protrusion together with distorted movement of the lower jaw causing class one speech impairment and 2% WPI. He reported a total WPI of 25%.
Concerning this assessment of Professor David, the assessor commented that the impairment assigned to impaired mastication was excessive as her condition is not the worst possible for restriction of diet to soft and semisolid food. The assessor agreed with the assessment by Professor David of Class 2 facial disfigurement and the level of impairment assigned. The assessor, though, had found no objective evidence of speech impairment and no signs of facial nerve injury.
The insurer had the claimant examined by Dr Curtis, who provided a report of
8 December 2020. Dr Curtis reported impaired mastication causing 12% WPI and deducted 5% WPI for previously identified right TMJ dysfunction. He assessed 3% WPI to Class 1 Facial Disfigurement due to preauricular scarring. The combined WPI was 10%. Dr Curtis expressed concerns about the assessment of Professor David, stating the claimant did not have Class 2 facial disfigurement and 19% WPI for mastication was the highest possible achievable and excessive. Dr Curtis assessed a higher deduction percentage for pre-existing TMJ dysfunction than Professor David. However, he did not describe what the pre-existing dysfunction was.
Assessor McGlynn agreed with the level of impairment for restricted mastication reported by Dr Curtis. He said the condition was not the worst possible and caused less than 19% WPI. However, Assessor McGlynn noted that Dr Curtis had not described what pre-existing dysfunction was present and why it caused a 5% WPI deduction.
The claimant did consult Dr D'Rosario on 16 June 2009 regarding internal derangement of her right TMJ. Dr Rosario had recommended the construction of an occlusal bite splint. There are no records indicating ongoing treatment after that time until after the subject accident.

Panel medical examination

Medical Assessor Curtin examined the claimant on behalf of the Panel on
14 October 2022. His report follows:
“1. The history of injury and subsequent treatment
Ms Seadon was injured in a motor vehicle accident on 02/01/2016. She was riding her bicycle down a hill on Cliff Road in Wollongong when she collided with a car which swerved in front of her. She said that the right side of her body struck the car and that she ended up lying on her back on the bonnet of the vehicle, with her bicycle still attached to a foot. Neither police or ambulance attended. She said that she hurt her neck and jaw on the right side and also her right shoulder and knee. She was able to make her way home, and the following day she attended her GP, Dr K Hyare, who recorded that she had sustained ‘injury to right and left knee, minor bruising, right shoulder is of concern, limited abduction and painful arc. Jaw pain. Right TMJ pain and crunching’. On 18/02/2016,
Dr Hyares' notes recorded ‘aggravated jaw, jaw locks, not improving despite physio’. She was sent for MRI imaging on 22/02/2016 which showed that the TM joint meniscus on the right side was anteriorly subluxed. Hypermobility of the condyle on that side was also noted . The notes of Matthew Whalen, Physiotherapist, record multiple visits from 15/01/16 to 16/11/18. On the 15/01/16, he noted that Ms Seadon presented with continued neck, upper thoracic and jaw pain and that her jaw mobility was 25% normal. Jaw mobility was noted to be 30% of normal on 05/02/16, 40% on 21/3/16, and 30% on 4/4/16. The last record, dated 16/11/18, in the documents records jaw mobility at 20% of normal. She saw her own dentist Dr Michael Finkelstein on 7/03/2016 and reported that her jaw was locking and that there was intermittent pain. His note of that date reported that she had similar problems following a fall from a bike six years previously, but it is not clear whether he was treating her himself at that time. Dr Finkelstein issued Ms Seadon with upper and lower bite splints, which did not improve her symptoms, and he then referred her to Dr Lydia Lim, Oral and Maxillofacial surgeon, whom she saw on 19/05/2016.
The cascade of treatment that followed over the following two years has been well documented. Reading through the records, the impression gained was that conservative management was the preferred option. On 29/7/2016, the claimant had an arthrocentesis of the right TM joint, a procedure which is essentially a washout of the joint followed by the installation of steroids. There was some initial improvement, but when she was reviewed at the end of the year there had been a relapse with further joint pain and locking. A further MRI on 8/11/16 shows some degenerative change in the mandibular condyle, with the disc still dislocated anteriorly. The following year on 31/7/17 Dr Lim carried out an arthroscopy of the right TM joint with the assistance of Dr Gary Bouloux, a professor of Oral and Maxillofacial Surgery from Atlanta, Georgia, and the author of multiple papers dealing with temporomandibular joint disorders. The arthroscopy findings were not encouraging, with severe synovitis and complete loss of the articular cartilage (grade 4 chondromalacia). The following year on 12/02/2018, she underwent a further surgical procedure to the right TM joint, involving the removal of the meniscus and replacement with a fat graft. There were no complications from surgery, but unfortunately, there was also no significant improvement in her symptoms of ongoing pain and reduced jaw opening. Another MRI on 18/7/18 showed that the head of the mandibular condyle had deteriorated further. Dr Lim's files note that her patient said that ‘she can't live like this’. The following month, on the 13/08/2018, she underwent a total joint replacement with a metal implant. Once again, there were no complications. Dr Lim noted on 11/1/19 that pain was much improved, but there was still reduced jaw opening.
Current symptoms. Ms Seadon said that she gets jaw pain every day, but it is not constant. The jaw movements involved with talking and eating will precipitate discomfort over time. She also said that her jaw opening was restricted, making talking and eating more difficult and that her jaw muscles would become fatigued with the effort. She said that if she were going out for an evening with friends and anticipated conversation and dining, she would take some oxycodone before she went out. Apart from the restricted jaw opening, Ms Seadon also said she could not chew properly because pressure on the right jaw joint caused pain. She could eat meat, but it had to be cut up very finely, and then she would have to rest after three or four mouthfuls. She could not manage a piece of sourdough toast. Her diet, therefore, was generally soft and had to be prepared in sufficiently small pieces to accommodate her reduced jaw opening. She said that the jaw opening could vary a little but that she used jaw exercises to try and maintain jaw opening at or above 20 mm because otherwise, jaw opening would spontaneously close, and she would be unable to function. The reduced jaw opening has created another problem in that she currently needs some dental treatment, and at the moment cannot find anyone who is prepared to operate on her mouth the way it is.
From the point of view of her appearance, she is aware of some disfigurement because her chin deviates to the right when she opens her mouth. She is also aware of some fine scarring on the right side of her neck and just in front of her right ear. She said that her right cheek in front of her ear was slightly numb.
Ms Seadon said that seven or eight years ago, she completed in triathlons and still enjoyed cycling although only over short distances. She also enjoys swimming but said that in both cases, the restriction of jaw opening caused her difficulties.
Was there any pre-existing impairment? On 21/01/2006, Ms Seadon attended the Emergency department of Wollongong Hospital with injuries sustained earlier that day from a bicycle accident. The ED records reported that she had run into the open door of a stationary car. She sustained lacerations to her left leg and left arm, some of which required to be sutured. There were no complaints of facial or jaw injury, and she was discharged home the same day.
Ms Seadon said that she did have some jaw problems after the accident but that these symptoms soon resolved, and she did not require to wear a bite splint. However, the single entry in her GP's files for 2006, on 5/6/06, makes no reference to the accident or any jaw symptoms. There is, however, a letter dated 12/12/2007 from Dr Nigel Curtis, Oral and Maxillofacial surgeon regarding a consultation he had with Ms Seadon on 07/12/2007 on behalf of an insurance company. The letter records that Ms Seadon consulted Dr Arthur Bosanquet, OMF surgeon, following the accident because of her jaw symptoms. An MRI study on 28/07/2006 showed some anterior displacement of the meniscus in the right TM joint. Dr Bosanquet arranged for some physiotherapy treatment but nothing else.
The GP files for 2007 record three visits, with six visits in 2008 and 19 visits in 2009. Over this period, only one entry, on 26/02/2009, made any reference to her jaw and then only stated that she needed a referral for another ‘jaw specialist’. On 16/06/2009 she saw Dr Robin D'Rosario, a Dental specialist, and his letter of that date stated that in view of Ms Seadon's history of symptoms and the findings on clinical examination, there was a diagnosis of ‘internal derangement of the right temporomandibular joint’. His letter referred to an MRI scan dated 18/05/2009, which revealed ‘a subtle anterior displaced disc in the right temporomandibular joint with reduction’. Ms Seadon was advised that conservative treatment was appropriate and this would involve physiotherapy and wearing an occlusal bite splint to be organised by her dentist. There is no documentation as to whether this treatment was carried out, and Ms Seadon denies wearing any splint.
Ms Seadon states that she had no jaw symptoms in the years preceding the accident in 2016. Examination of the GP files throughout 2010-2015 revealed multiple visits regarding managing various complaints, but these did not include any symptoms of jaw discomfort.
Findings on examination. Ms Seadon was a lady of 47 years, of moderate height and build and somewhat overweight. She had a fair complexion, was well-groomed and had a pleasant manner.
Examination of her face revealed no apparent abnormality, but the jaw opening caused a noticeable deviation of the chin to the right. The maximum interincisal distance between the anterior teeth was measured at several points during the examination and varied between 12 and 16 mm. Neither TM joint was tender to palpation, and no crepitus could be felt on either side. She had a full dentition that appeared to be in reasonably good condition and had no obvious disturbances to the dental occlusion.
On the right side of the neck, just below the jaw angle, there was a pale, flat, soft scar extending for 4cm. There were some fine suture marks, and the scar was not tender to palpation. Immediately in front of the right ear, another similar scar was quite pale and difficult to see, associated with a small pit in the skin. Sensation was present in the skin of the cheek in front of the ear (an area of approximately 7x 5cm). However, the quality of sensation appeared to be altered because Ms Seadon found that even gentle palpation of the area was unpleasant. Facial movements were normal and symmetrical. During the assessment, there was no evidence of any hesitation or impediment in her speech.
Comments on Whole Person Impairment.
The insurer raised concerns that the motor vehicle accident in 2016 either resulted in no injury to the jaw or, failing that, was likely to have resulted only in a temporary jaw problem which eventually settled. The insurer felt that
Ms Seadon's current disabilities were entirely due to the surgical treatment she had received.
The accident report in 2016 suggests that the right side of Ms Seadon's body sustained a significant impact in the collision. It is clear that an accident of this type could have injured the right TM joint. The history of Ms Seadon and the documentation show that her symptoms of jaw pain were continuous and uninterrupted from the date of the accident up to her initial consultation with
Dr Lim on 19/05/2016. There is no evidence that her jaw symptoms were temporary, and a causative link to the accident appears to be well-established. There is also no evidence that the surgical treatment Ms Seadon received has resulted in increased disability. Although there is persistent impairment, her condition appears to be stable and not deteriorating. The indications for the total joint replacement appear to have been reasonable, namely end-stage joint disease. Total implant replacement of the TM joint is a reasonably recent development. The procedure appeared first in the 1970s, but it is only in the last ten years, with implant improvements, better surgical results have been obtained, and joint replacement has been more widely adopted. The usual indication is end-stage arthritis rather than post-traumatic ankylosis, a relatively rare complication in the Western world.
The Motor Accident Guidelines (effective from 1 June 2018) state that ‘where loss of structural integrity occurs as a result of the dental injury, the injury must be assessed for a loss of functional capacity (mastication) and a loss of structural integrity very (cosmetic deformity) and any impairment combined.
Impairment of mastication: The Guidelines (para 1.197) also refer the assessor to Table 6, page 231 AMA 4 Guides which deals with the relationship of dietary restrictions to impairment and advises that the first category should be 0-19%, not 5-19%. Table 6 provides an impairment range of 0-19% WPI, depending on the extent to which the diet is restricted to semisolid or soft foods. To determine where Ms Seadon's impairment lies on this range, it is helpful to refer to the documentation regarding her pain management and the restriction of jaw opening. There are, unfortunately, no GP records documenting her progress since the joint replacement operation in August 2018. However, a letter from her Psychiatrist Dr Stevenson on 6/12/19, refers to her ongoing use of opioid analgesics, and a letter from Dr Lim on 15/7/2020 also refers to her intermittent use of hydromorphone, a potent opioid analgesic. Dr Lim's documents also refer to the ongoing need for jaw stretching exercises monitored by physiotherapists. A physiotherapy entry dated 23/4/2019 reported on this treatment and described the home program of exercise that Ms Seadon would need to follow. The documentation supports Ms Seadon's history of current jaw pain and the need for intermittent opioid analgesics. Jaw opening on examination was found to be significantly restricted, which appears to be a constant rather than an intermittent problem. The impairment is therefore rated at the top of the range, i.e. 19% WPI.
Cosmetic deformity. The Guidelines direct that facial scarring and disfigurement are assessed separately to scarring elsewhere on the body…. and that assessment using AMA 4 could either be undertaken using chapter 13, the skin or section 9.2 page 229 ‘the face’. The Panel adopts use of section 9.2, in which case impairment falls in the Class 2 category (5-10% WPI) because there has been loss of supporting structure of part of the face, namely the normal right temporomandibular joint, which has resulted noticeable deformity due to deviation of the chin on jaw opening. This deformity is relatively minor and lies on the lower end of the scale at 5% WPI. The fine scarring on the face and neck is included in this assessment.
Altered sensation on the right side of the face. It is very likely that the parotid branches of the auriculotemporal nerve have sustained some damage during the surgery. The nerve, a branch of the third division of the trigeminal nerve, passes very close to the TM joint and would be vulnerable to injury. However, branches of the auriculotemporal nerve that pass to the ear and the temple area appear to have escaped injury. Paragraph 1.173 in the Motor Accident Guidelines directs that the words ‘sensory disturbance’ be added to table 9, page 145 of AMA 4, which provides impairment ratings concerning the trigeminal nerve. Table 9 indicates that 0 to 14% WPI can apply to mild impairment due to uncontrolled facial neuralgic pain or sensory disturbance. The claimants disability is a serious, and not mild, impairment. In these circumstances it is reasonable to apply the maximum impairment rating of 14%. However, paragraph 1.173 states that the mandibular division of the trigeminal nerve can only attract 30% of whatever value is selected. This would reduce the impairment to 30% of 14% or 4.2%, and this value should be reduced further by 75% because only a small part of the mandibular division appears to be affected. The final impairment rating for facial sensory loss is 1 % WPI (after rounding).
Combining Impairments results in a total of 24% WPI. On the combined tables this is 19% +5% [23] +1% = 24%
Deduction for a pre-existing condition. The guidelines (para 1.31) state that ‘if there is objective evidence of a pre-existing symptomatic permanent impairment in the same region at the time of the accident, then its value must be calculated and subtracted from the current WPI value’. The guidelines define impairment in paragraphs 1.9 and 1.10 as a deviation from normality in the body part or organ system and its functioning. This is consistent with the WHO definition, which says that impairment is any loss or abnormality of a psychological, physiological or anatomical structure or function. There is evidence of altered anatomy within the right temporomandibular joint dating back to the MRI taken in 2007. When this partial subluxation occurred is not clear, but between 2009 and the accident in 2016, the right TM joint appears to have been asymptomatic. The pre-existing subluxation is an abnormality of anatomical structure and therefore attracts a deduction. However, as the subluxation appears to have been asymptomatic for many years, the deduction is small at 10%.u
This equates as 24% less 2% rounded down and a total of 22%.
Final whole person impairment is 22% WPI.”
The Panel adopts the report and findings of Medical Assessor Curtin.

Causation

In Kinchela v Insurance Australia Group Ltd t/as NRMA Insurance[1] Justice Walton set aside the decision of a Medical Review Panel. The discussion in Kinchela concerning the correct principles to apply relating to causation are set out below:
"[38] The second defendant's task was not to answer the question of whether there was any contemporaneous evidence, or corroborative evidence, to support an injury to the right 2nd toe, but whether the accident contributed to the right 2nd toe infection, avulsion of the nail and ultimate right 2nd toe amputation. By focussing only on whether there was a contemporaneous record of complaint in the clinical notes or the ambulance notes, the actual question it was required to consider was overlooked – did the motor vehicle accident materially contribute to the right 2nd toe amputation?
[39] The second defendant fell, therefore, into the type of error identified in Owen v Motor Accidents Authority of NSW (2012) 61 MVR 245; [2012] NSWSC 650 at [51]- [52]; Bugat v Fox (2014) 67 MVR 150; [2014] NSWSC 888 ("Bugat"); AAI Ltd t/as GIO v McGiffen (2016) 77 MVR 348; [2016] NSWCA 229 ("McGiffen"). The error identified is in treating the absence of a contemporaneous complaint or report of injury as determinative of the issue of causation.
[1] [2021] NSWSC 804, Kinchela.

In Bugat, RS Hulme AJ held that the lack of contemporaneous evidence cannot be determinative of causation. His Honour stated at [31]-[32]:
“[31] One of the pivotal questions for the Panel was whether the injuries of which the plaintiff complained had been caused (or materially contributed to) by the motor accident she alleged. To that question the presence or absence of contemporaneous evidence of injury was relevant but not determinative in circumstances where there was other evidence, in particular the plaintiff's claim form made but 15 days later, the remarks of Dr Hor in his report of 13 July 2011, and the plaintiff's statements which the certificate discloses were made to the Panel to the effect that at the time of the accident she suffered 'pain in her neck going out to both shoulders.
[32] While I accept that, as an administrative decision-maker, the Panel's reasons should not be subjected to 'minute and detailed textual criticism in the hope of finding something on which to base an argument' [Allianz Australia Insurance Ltd v Motor Accidents Authority (NSW)(2006) 47 MVR 46, [2006] NSWSC 1096 at [36]] in expressing themselves the way they have, the Panel have clearly shown that they have regarded what they perceived as the absence of contemporaneous evidence as determinative on the issue of causation. In doing so they erred, the error being one apparent on the face of the record.”
In McGiffen, the Court of Appeal held at [64] – [65]:
“[64] The question that the review panel was required to address was not simply whether there was any contemporaneous evidence of complaint about an injury to the lumbar thoracic spine. It included whether Mr McGiffen's lumbar thoracic spinal injury was causally related to the 'gait derangement', itself caused by the accident. That is, was the accident a contributing cause of a lumbar thoracic spinal injury by reason of the gait derangement caused by the accident.
[65] In deciding causation solely on the basis of the existence or otherwise of contemporaneous evidence of complaint of injury to the thoracic spine the review panel only partially addressed the question posed by s 58(1)(d). For that reason, the decision recorded in the Panel's Certificate must be treated as a purported and not real exercise of its statutory function under s 58(1)(d), leaving that function unexercised, and the Authority and the Panel liable to the relief granted by the primary judge for jurisdictional error.”
It was held that the second defendant failed to apply the correct test of causation as set out in the relevant Guidelines informed by s 5D of the Civil Liability Act 2002 (the CLA) and the common law. As result, the second defendant failed to apply the appropriate legal test in order to discharge its jurisdictional function.
As Justice Walton observed in Kinchela the CLA is relevant. In s 3B various liability is excluded from the Act; however, sub-section (2) provides that "Divisions 1-4 and 8 of Part 1A (Negligence)" apply to motor accidents. Sections 5D and 5E relating to causation are in Division 3 of the CLA. Therefore, they apply to the Motor Accident Injuries Act 2017. The common law principles, as discussed in the above authorities, apply.

The Motor Accident Guidelines

The Guidelines identify the test for causation in cls 6.6 and 6.7.[2]
[2] Causation is defined in the Glossary at page 316 of the AMA 4 Guides.
In Ackling v QBE Insurance (Aust) Ltd,[3] Johnson J indicated that the task of a review panel in assessing whether an injury was caused by the relevant accident is "a practical one". His Honour also observed that a review panel will derive practical assistance from the Guidelines when undertaking the task of assessing causation.[4]
[3] [2009] 75 NSWLR 482; [2009] NSWSC 881.
[4] At [87]. Justice Johnson was then referring to the predecessors to clauses 6.5 - 6.7 of the Motor Accident Guidelines, being clauses 1.7 – 1.9 of the Permanent Impairment Guidelines.
In Owen v Motor Accidents Authority (NSW),[5] Campbell J adopted Justice Johnson's approach with a caveat touching upon the CLA:
"Given that the task of the Medical Review Panel in determining the causation question is not solely a medical determination within the expertise of the assessor's constituting the Panel, the position has, with respect, been aptly put by Johnson J in Ackling at p 500 [87] that the Assessors will derive practical assistance from this part of the Permanent Impairment Guidelines. But it is well to emphasise that the question to be assessed is one of legal causation involving mixed questions of fact and law arising principally from the law of negligence as modified by Civil Liability Act 2002, s 5D. (See s 3B(2))."[6]
[5] [2012] 61 MVR 245; [2012] NSWSC 650.
[6] At [27].

The Civil Liability Act 2002

Justice Campbell in Owen, said s 5D of the CLA needs also to be considered when assessing causation.

65.Section 5D of the CLA provides:
"General principles
(1) A determination that negligence caused particular harm comprises the following elements:
(a) that the negligence was a necessary condition of the occurrence of the harm ('factual causation'), and

(b) that it is appropriate for the scope of the negligent person's liability to extend to the harm so caused ('scope of liability')."

There are two elements to address when assessing causation under s 5D(1):
"factual causation";[7] and
"scope of liability".[8]
[7] See s 5D(1)(a) of the CLA - this is the statutory restatement of the “but for” test (see Adeels Palace Pty Ltd v Moubarak [2009] 239 CLR 420; [2009] HCA 48 at [45]) i.e. but for the negligent act or omission, would the harm have occurred?
[8] See s 5D(1)(b) of the CLA. See Adeels Palace at 42; Wallace v Kam [2013] 250 CLR 375; [2013] HCA 19 at [12].

Did the injury to the claimant's TMJ and subsequent surgery arise from the accident?

Assessing "factual causation" and "scope of liability" involves making value judgments.[9]
[9] There is a conflict between s 5D and the Guidelines. Section 5D requires the use of the “but for” test and the Guidelines state that while the “but for” test may be useful in some cases, it “is not a definitive test and may be inapplicable in circumstances where there are multiple contributing causes.”^{^[9]}
The insurer says that the claimant did not sustain any permanent injury to her TMJ due to the accident. Further, the insurer says the accident did not give rise to any assessable permanent impairment.
The insurer says its liability is limited to the temporary injuries resulting from the subject accident.
The insurer says that the opinions of both Professor David and Dr Curtis were related to injuries caused by the surgery performed by Dr Lim. The insurer says that this surgery was not approved by it.
The insurer says that the mastication and facial disfigurement injuries are caused by the string of surgeries performed on the claimant TMJ by Dr Lim and not the temporary injury submitted by the insurer to arise from the subject accident.
The insurer says that by failing to address its submissions, the assessor failed to identify whether the cause of the claimant's symptoms was an accident-related pathological change or due to the surgical procedure which the insurer has maintained is not related to the accident.
The insurer says that any injury the claimant sustained as a result of the accident manifested as a temporary aggravation of a pre-existing condition and that pre-existing condition was exacerbated by the unwarranted surgeries performed by Dr Lim.
The insurer further submitted that any assessment of permanent impairment must make apportionment concerning the claimant's pre-existing conditions and the effects of the claimant's post-accident injuries, treatments/unsuccessful surgeries and diagnoses.
The insurer says that the claimant did not attend hospital following the accident. The insurer referred to the report of Dr Curtis, who said in his February 2019 report that "It does immediately appear a little strange that for a patient who did not attend nor was taken to a hospital following this accident that major surgery carried out by Dr Lim, in this case, would be either warranted or appropriate".
By way of summary, the insurer submitted:
(a)   Any injuries sustained by the claimant as a result of the accident consisted of a temporary aggravation of pre-existing conditions.
(b)   The claimant's current TMJ condition arose due to a pre-existing significant TMJ displacement which was exacerbated by the unwarranted surgeries performed by Dr Lim and Dr Bouloux.
(c)   Should the assessor (in the initial assessment) make any findings of permanent impairment, the insurer submits as follows:
(i)the assessor (in the initial assessment) should deduct the claimant's pre-existing conditions from any assessment of WPI, and
(ii)the assessor (in the initial assessment) should make an apportionment to allow for the effects of the claimant's unwarranted and unsuccessful surgeries and deduct this from any assessment of WPI.
The claimant says that what is relevant is whether the claimant developed right temporomandibular joint pain because of the subject accident.
The claimant says that while the insurer has raised the issue of causation in its submissions, this runs counter to Dr Curtis' assessment of 10% WPI and his opinion on page 5 of his report of 12 February 2019 that:
"I do note that Ms Seadon did suffer injuries over the right side of her body to the right shoulder, knee and neck region and this is consistent with a possible injury to the right temporomandibular joint during the accident. In motor vehicle accidents of this form of injury a flexion extension or whiplash injury of the neck is suffered to the jaw joint causing distraction of the joint meniscus resulting in the mentioned internal derangement of the temporomandibular joint."
The Panel acknowledges that the claimant injured her TMJ in 2006. The claimant did have occasional treatment for the injury over three years. There is nothing to indicate any treatment or complaint arising out of the accident from 2009 to the time of the injury on 2 January 2016.
On the day of the accident the claimant was riding her bike on the road and collided unexpectedly with a car. She had no warning of the collision, and it is not inconceivable that she was shocked by the impact of this collision. A car -v- bike injury is one in which the cyclist is at a disadvantage in the area of protection and collision with a car. That is obvious.
The Panel accepts that it is probable that the claimant could have injured her right jaw in the accident. There are apparently no witnesses available to verify the nature of the collision and the dynamics of the claimant falling from her bike, over the insured car's bonnet and onto the roadway. There is no evidence available to the Panel from the insured driver about the accident and impact. However, the Panel accepts that by its nature, the collision would have been a sudden forceful impact for which the claimant had little protection.
The insurer says that the claimant's current facial disfigurement and mastication difficulties are caused by the surgery performed by Dr Lim and not the temporary injury suffered by her in the accident. The Panel disagrees that the claimant suffered aggravation of pre-existing injuries in the accident. She sought treatment within reasonable proximity to the time of the accident and has undergone continuous treatment, including surgeries. The Panel does not accept that at the time of the accident, the claimant suffered a pre-existing disability of her TMJ. She had not sought treatment for this since 2009. If she had any disability from the 2006 injury, then it was insignificant, and the Panel has made a 10% deduction acknowledging the small effect.
The insurer says that it did not approve surgeries by Dr Lim and that the unwarranted surgeries of Dr Lim exacerbated her condition. The Panel has dealt with this in its examination findings above. In addition, the Panel considered the surgery following the accident to have arisen as a result of the accident, noting, in particular, the dynamic forces that could arise in a bike -v- cyclist sudden impact accident.
As Medical Assessor Curtin said in his examination findings, there is no evidence that the surgical treatment received by the claimant has resulted in increased disability. The insurer has made this assertion but without substantiation. The indications for the total joint replacement were, in the Panel's opinion, reasonable, namely end-stage joint disease.
The claimant has provided a history which, when viewed with medical records, shows that her symptoms of jaw pain were continuous and uninterrupted from very soon after the accident to the time of her consultation with Dr Lim on 19 May 2016.
All of Dr Curtis, Professor David and the assessor accept the link between the injuries and the accident when all provide their WPI assessments. The assessments all indicate that these medical practitioners accepted the injuries suffered by the claimant as not a temporary aggravation of a pre-existing condition.
The insurer asserts that the opinions of both Dr Curtis and Professor David were related to injuries caused by the surgery performed by Dr Lim. The Panel does not accept this as the surgery was a necessary treatment of the injuries suffered by the claimant as a result of the accident. The Panel reiterates that the surgery was necessary to treat end-state joint disease.

Conclusion

The Panel revokes the Certificate of Assessor McGlynn dated
21 February 2022.
The Panel finds that the injuries suffered by the claimant in the accident on
2 January 2016 are causally related.
The Panel finds a total WPI of 22%.

Clause 6.6 provides:
“Causation means that a physical, chemical or biologic factor contributed to the occurrence of a medical condition. To decide that a factor alleged to have caused or contributed to the occurrence or worsening of a medical condition has, in fact, done so, it is necessary to verify both of the following:
(a) The alleged factor could have caused or contributed to worsening of the impairment, which is a medical determination.
(b) The alleged factor did cause or contribute to worsening of the impairment, which is a non-medical determination.”
Clause 6.7 provides:
“6.7 There is no simple common test of causation that is applicable to all cases, but the accepted approach involves determining whether the injury (and the associated impairment) was caused or materially contributed to by the motor accident. The motor accident does not have to be a sole cause as long as it is a contributing cause, which is more than negligible. Considering the question 'Would this injury (or impairment) have occurred if not for the accident?' may be useful in some cases, although this is not a definitive test and may be inapplicable in circumstances where there are multiple contributing causes.”

[2023] NSWPICMP 181

4 May 2023