Nguyen principle -NSW MAA injury case law and IME analysis.

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In a judgement 3 May 2011 (Nguyen v Motor Accidents Authority of New South Wales and Anor (2011) NSWSC 351 Supreme Court NSW) His Honour Hall reviewed a case involving a MVA 26 March 2007 with a diagnosis of soft tissue injury to the claimant's cervical spine and discomfort in her left shoulder.There was no contemporaneous evidence that a direct injury had occurred to either shoulder.The Wollongong Hospital records 26 March 2007 to 18 July 2007 record the claimant complaining of neck pain passing to her shoulder.

The Medical Assessment Service review assessor determined 5 % PI arising from the neck injury and that any symptoms or impairment to the claimant's shoulder was NOT causally related to the accident.The observed restricted ROM to the shoulder was noted but not deemed to be due to an injury to the shoulder from the MVA and the PI was 5 % solely relating to the assessed neck injury.

The Proper Officer upheld the findings after an application for review  which cited failure to assess WPI for loss of ROM shoulder ( Section 63, MACA 1999).

The Supreme Court found that the use of "as a result of" ( Section 58(1)(d) of the MACA should NOT be given a "broad construction" in discussing the application of common law causation principles. His Hon Hall found that "impairment in one or both of the (claimant's) upper limbs consequent upon injury to the cervical spine would be compensable as the natural consequence of spinal injury ".His Honour found , in essence, that medical assessment of PI required an assessment of the injury to the cervical spine and its direct effects on related areas including, the claimant's shoulder.

The Nguyen decision is an important one for claimants, doctors, lawyers, IMEs, decision makers , lawyers and jurists.It found, inter alia, that if a plaintiff has not sustained a direct injury to a body part but is experiencing symptoms such as 'referred pain' then that 'referred pain' is assessable at MAS.This extends to lumbar spine and hips.

If a claim of referred indirect injury causation is in question then a meticulous assessment is required.The decision does not dictate that causation is proven but that it needs to be explored and considered.

Now the importance( AGAIN !) of  ALL contemporaneous  accident, incident, medical , ambulance and hospital records reaches a higher level of importance if a Nguyen principle case is at hand.

The IME /medicolegal assessor must determine if the 'referred' portion ,e.g. shoulder, was directly injured and if so a proper definitive assessment of that body part be performed including investigations such as MRI etc. If there was no direct injury then the assessor must be very experienced and perform meticulous  history and examinations.Examinations with the claimant fully clothed in a few minutes are clearly insufficient.

The IME /medicolegal assessor must be knowledgable on the myriad of clinical relationships between the directly injured part ,e.g. the cervical spine ,and the 'referred part' ,e.g. the shoulder. 

Shoulder symptoms including reduced ROM can arise from many causes: joint stability issues(adhesive capsulitis, labral tears,joint disruption; Joint dynamic control( rotator cuff lesions,scapulothoracic stabilisers, impingement- subacromial / supraspinatus) and true referred pain( cervical, cardiac, oesophageal,diaphragmatic lesions etc). Was there a legator scapulae syndrome?Were the paracervical muscles and ligaments intact on MRI? Did the radiologist or spinal surgeon comment on ALL, PLL etc?

Then skill is needed to measure the 3 planes of shoulder motion (Abd& Add 180/50; F&E 180 and 50 and IR/ER 90 and 90 (normals) and compare with asymptomatic contralateral side. Active and passive testing may need to be performed with great care.

Consistency and validation testing must be known as appears in the AMA Guides and 2017 , 2007 and 1999 MA Guides.

The assessor must be able to define a medically explicable relationship between the injury site and the 'referred' site and exclude factors such as primary pathology( >50% shoulders >50 years old have rotator cuff tears) and other matters such as cardiac, diaphragmatic etc causation.

If a medical relationship can be reliably found to explain the secondary('referred') site symptoms to the primary injured site(e.g. cervical spine) then this has to be documented with sound reasoning at a reasonable degree of medical certainty.If it is not at this level then the link is  not reliable or...reasonable.

The experienced assessor MAY recognise that some shoulder pain or painful restriction to movement may be part of the C5 radiculopathy assessed and not duplicitously assess WPI for shoulder symptoms that are well accounted for by the WPI assessment of the primary injury- this is a well established principle of PI assessment recognised by all experienced IMEs.Similarly restriction of SLR ( lumbar nerve tension sign) is part of the lumbar WPI and not necessarily a 'referred' WPI pertaining to a referred hip region injury.. 

These are but 2 examples of the importance of a well trained , highly experienced and carfeul assessor with performance of a thorough history ; review of ALL contemporaneous incident /medical /ambulance/hospital records ; personal viewing of all radiology studies ( and recognising normal age related and anatomical normal variations)and detailed and thoroughly documented physical examination.

Then the assessor must undertake WPI assessment if he/she believes that the injury/injuries are at MMI and permanent( as defined) and combine (not add ) this WPI to that in the cervical region if it is a cervical spine-> shoulder Nguyen case type.

The potential for duplicitous ( WPI is accounted for from the injured part and further WPI may be unwarranted) and unrecognised WPI ( as in Nguyen principle case) exists in such complex cases requiring the highest level of assessment.

In practice however the prevalence of non injured part WPI assessment is not common but is worthy of careful consideration by vigilance in IME and medico legal assessors performing careful and meticulous assessments.

All methodology must be documented and the IME /medicolegal assessor must be familiar with the provisions in the relevant MAA guides depending on DOI ( 1999,2007 and 2017 MA guides ). 

The 2017 MAA Guides contain important changes that were in the 2007 MACA guides.

NOTE: This is an educational article and is not intended to be medical/legal/medicolegal advice and all the views and comments are those of the author. The reader is advised to read the AMA  Guides and MAG NSW and make his/her  own personal conclusions and determinations.

The author is a senior neurosurgeon and Honorary Adjunct Associate Professor who obtained Master CIME in AMA 4 ,5 and 6 in 2017 by examination by the American Board of Independent Medical Examiners (ABIME) .

Dr Michael Coroneos   MCIME  FRACS  FRCS(EDIN)SN  FRCS(ENG)  FRCS(IRE)  FRCS(Glasg)  FACS  FWAMS  MB BS(1st Class Honours, 1980)