PreEmployment Exams A Spinal Focus Spinal Intrinsic Risk

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Pre-Employment Exams A Spinal Focus Spinal Intrinsic Risk Factors Dr David Mc. Grath 2008

Pre-Employment Exams A Spinal Focus Spinal Intrinsic Risk Factors Dr David Mc. Grath 2008 www. drdavidmcgrath. com. au

Questions • What are They ? • How Bad are they ? • Can

Questions • What are They ? • How Bad are they ? • Can we find them ? • Should we find them ?

Possible Risk Factors • Current Pain • Old Injuries • Congenital or Acquired Deformities

Possible Risk Factors • Current Pain • Old Injuries • Congenital or Acquired Deformities • Anthropometric Extremes • Age • Gender • Level of Fitness • Strength and Robustness • Imaged Pathology

Assessing the Risk (hypothetical non specific risk factor OR=17 ) Risk Present Risk Absent

Assessing the Risk (hypothetical non specific risk factor OR=17 ) Risk Present Risk Absent Bad Outcome 5 Good Outcome 5 5 85

Deductions • With a prevalence of 10%, and an absolute risk contribution of ½,

Deductions • With a prevalence of 10%, and an absolute risk contribution of ½, we need approximately 100 examinations to reduce, the adverse employment outcomes by 50% (by not employing or effective risk management )

Detection (sensitivity 80%, specificity 77% ) Risk Factor Present Absent Diagnosed 8 20 Not

Detection (sensitivity 80%, specificity 77% ) Risk Factor Present Absent Diagnosed 8 20 Not 2 Diagnosed 70

The Risk Adjusted Company (Perfect Intervention=All those identified with risk factor prevented from bad

The Risk Adjusted Company (Perfect Intervention=All those identified with risk factor prevented from bad outcome NNT=2) First number indicates employees with risk factor Second number indicates, employees without risk factor Bad Outcome Risk 0+1=1 Diagnosed & Intervention (n=28) No Risk Factor 1+4=5 Diagnosed (n=72) Good Outcome 8+19=27 1+66=67

Risk Intervention Effectiveness (Compared to natural company history with 50% bad outcome) NNT=1/(6/8 -4/8)=4

Risk Intervention Effectiveness (Compared to natural company history with 50% bad outcome) NNT=1/(6/8 -4/8)=4 Those with risk factor Intervention Bad Outcome 2 No 4 Intervention Good Outcome 6 4

Company after Realistic Intervention (NNT=4) Bad Outcome Good Outcome Risk Intervention 2+1=3 (n=28) 6+19=25

Company after Realistic Intervention (NNT=4) Bad Outcome Good Outcome Risk Intervention 2+1=3 (n=28) 6+19=25 No Risk Intervention (n=72) 1+66=67 1+4=5

Non-Hiring Option (28 at-risk diagnosed and not hired, leading to 72 remaining ) (8

Non-Hiring Option (28 at-risk diagnosed and not hired, leading to 72 remaining ) (8 with risk factor excluded, 20 non risk employees excluded ) (72 remaining employees, 2 have risk factor, 70 don’t ) 50% of the 2=1 and 5(1/2) % of 70=4 have bad outcome Bad Outcome Good Outcome Screening and Discarding 1+4=5 1+66=67 Without Screening 5+5=10 5+85=90

After Hiring another 28 in 139 exams total (excluding 39 candidates, only 11 of

After Hiring another 28 in 139 exams total (excluding 39 candidates, only 11 of which have the risk factor, while 28 don’t ) Bad Outcome Good Outcome After Screening 1. 5+6=7. 5 No Screening 5+5=10 1. 5+91=92. 5 5+85=90

Comparing Outcomes Bad Outcome Good Outcome No Screening 10 90 Screening & Intervention Screening

Comparing Outcomes Bad Outcome Good Outcome No Screening 10 90 Screening & Intervention Screening & Rejection 8 (NNT=4) 6 (perfect Rx) 7. 5 92 94 92. 5

Remember • Odds Ratio=17 (ie relatively high) • Detection se=80% sp=77% (ie good) •

Remember • Odds Ratio=17 (ie relatively high) • Detection se=80% sp=77% (ie good) • NNT=4 Risk Intervention (ie good) • Interventions for 28% (20% no risk) • Exams=139% with rejection strategy • Rejected applicants without risk=28 (20% of • candidates) Rejected applicants with risk=11 (8% candidates, but 10% prevalence)

Summary • With Detection/Risk Intervention strategy, we examine 100% employees, 20% less bad outcome,

Summary • With Detection/Risk Intervention strategy, we examine 100% employees, 20% less bad outcome, and intervene on 28% employees (20% of which don’t have risk) • With Detection/Don’t hire policy, we have, 25 % less bad outcome, and examine, 139 % prospective employees, reject 20% with no risk

Things To Consider • Cost of Exams • Stigma to rejected applicants • Cost

Things To Consider • Cost of Exams • Stigma to rejected applicants • Cost of interventions • Cost and Significance of Bad Outcomes

Armed Forces • Cost of Training High • Cost of Intervention High • Cost

Armed Forces • Cost of Training High • Cost of Intervention High • Cost of Bad Outcome High • Cost of Exams relatively Cheap • Stigma of Rejection ? ?

Trial Of Fire • Relax initial entry criteria • Boot Camp survival test (many

Trial Of Fire • Relax initial entry criteria • Boot Camp survival test (many compo claims arise from this period) • Chance of re-entry if fitness or strength is limiting factor • Not generally available to high end, service skill occupations e. g. pilots, aircrew

Spines • What’s Worth Looking For ? • What’s the best detection method ?

Spines • What’s Worth Looking For ? • What’s the best detection method ? • What’s the cost/benefit ? For either the non hire or risk intervene option • What are technical, legal, ethical, social limitations

Recurrent Back Pain • LBP >30 days during past year, increased risk OR=4. 8

Recurrent Back Pain • LBP >30 days during past year, increased risk OR=4. 8 long lasting BP OR=3. 3 Leg pain OR=5. 9 Medical Discharge (Hestbaek 2005) n=1711 Danish Military Recruits Conscription • Generally this factor is thought to have good Se, but poor Sp. Also poor Reliability.

Muscle Strength • Strength testing alone has no predictive value for work place injuries

Muscle Strength • Strength testing alone has no predictive value for work place injuries (Harbin G 2005) n=2, 482 Food factory study • Likely discrimination against women, certain ethnic groups, and handicapped, using the Detect/Don’t hire policy

Job Matching • With employees who had matching physical capacity, to inherent requirements of

Job Matching • With employees who had matching physical capacity, to inherent requirements of job, incidence of injuries was 3% • With employees, without matching capacity, incidence of injuries was 33% NNT=3 in this instance (Harbin G 2005) Factory Workers • 38% physical theoretical mismatch in an industry with a high incidence of LBP (Pedersen DM 2005) Utah Mechanics

Scoliosis etc • Kyphosis/lordosis (side plane) • Skewed pelvis • Scoliosis (frontal plane) •

Scoliosis etc • Kyphosis/lordosis (side plane) • Skewed pelvis • Scoliosis (frontal plane) • Rotoscoliosis (front, axial) • Sparse reliable, valid data, on occupation outcome measures • OR=3. 0 LBP adolescents (Kovac’s 2005)

Congenital Malformations • Dysraphism (usually detected at birth) • Dysegmentalism (sacralisation, lumbarisation, accessory articulations

Congenital Malformations • Dysraphism (usually detected at birth) • Dysegmentalism (sacralisation, lumbarisation, accessory articulations ) • No valid data

Disc Disease • Isolated Disc Resorption (significant loss of disc height) • Bulges •

Disc Disease • Isolated Disc Resorption (significant loss of disc height) • Bulges • Prolapses • V. E. P Osteophytic Outgrowth • Sparse, unreliable data

Scheuermann’s Disease • The definition, has relaxed from the original thoracic kyphosis deformity (to

Scheuermann’s Disease • The definition, has relaxed from the original thoracic kyphosis deformity (to a number of vertebral end plate deformities) • No reliable /valid data on risk for various occupations

Isthmic Spondylolitheses • No reliable /valid data on occupational risk • Overall risk perceived

Isthmic Spondylolitheses • No reliable /valid data on occupational risk • Overall risk perceived to be low

Intervertebral Canal Pathology • Congenital or Acquired Spinal Stenosis • Spinal Cord Pathology •

Intervertebral Canal Pathology • Congenital or Acquired Spinal Stenosis • Spinal Cord Pathology • Other Spinal canal Pathology • No Reliable or Valid data for occupations

Muscular Imbalance • Signs of muscular Irritability • Associated geometry deformity • Associated poor

Muscular Imbalance • Signs of muscular Irritability • Associated geometry deformity • Associated poor dynamic range of specific joints • Low reliability (inter or intra observer ) • No valid data • Assume similar to scoliosis ? (OR=3 LBP)

Body Mass Index • Mild positive association, increasing for longer pain duration • Positive

Body Mass Index • Mild positive association, increasing for longer pain duration • Positive association, unlikely to be causal, as correlation disappears with monozygotic twins (Leboeuf Yde 1999 ) n=29, 424 twins “Probable, weight increase with chronicity”

Co-Morbidity • Positive association of LBP and headache and asthma (Hestbaek L 2006 )

Co-Morbidity • Positive association of LBP and headache and asthma (Hestbaek L 2006 ) n=9, 567 Age cohort 12 -22 The presence of two other disorders increased the probability of LBP considerably Frail subgroup drops from 60% to 25 % at age 22. “a common origin should be considered”

Smoking • Association between smoking and LBP (Leboeuf-Yde 1999 ) The association is not

Smoking • Association between smoking and LBP (Leboeuf-Yde 1999 ) The association is not likely to be causal, as there is no dose response relationship, and disappears with twin study

LBP Adolescents • Strong correlation between adolescent LBP and adult LBP OR=4 • 8

LBP Adolescents • Strong correlation between adolescent LBP and adult LBP OR=4 • 8 year follow up study • N=10, 000 • Dose Response Relationship (Hestbaek L 1999 Danish Study) “Future Research, should focus on young Population “

LBP Schoolchildren • LBP not related to heredity • Scoliosis related to heredity •

LBP Schoolchildren • LBP not related to heredity • Scoliosis related to heredity • Strong association between pain in bed or upon arising and LBP. OR=13 • LBP and Scoliosis OR=3 • LBP and Leg length difference OR=1. 3 • LBP and sport practice more than 2/week OR=1. 2 (Kovacs FM 2005 Spanish cross sectional study n=16, 394)

LBP and Schoolchildren (continued) • No Association for LBP and alcohol intake, cigarette smoking,

LBP and Schoolchildren (continued) • No Association for LBP and alcohol intake, cigarette smoking, BMI, book transport method, hours of leisure sitting. • Point prevalence (7 day period) was 17% boys and 33% girls.

Spondylosis • Not valuable as a diagnoses • The population attributable risk is around

Spondylosis • Not valuable as a diagnoses • The population attributable risk is around 15%, as an association with LBP, and thus can be viewed as an intrinsic risk factor.

Gender • Women more at risk of developing chronic LBP OR=2. 65 Military Physical

Gender • Women more at risk of developing chronic LBP OR=2. 65 Military Physical training OR=2. 49 Military Occupation OR=2. 91 Off Duty Activities OR=0. 05 Sporting Activity OR=3. 17 Overall (Strowbridge NR 2005) n=928 new cases English Military Prospective Study

Intelligence and Education • In one study, LBP in military recruits, intelligence protects OR=5,

Intelligence and Education • In one study, LBP in military recruits, intelligence protects OR=5, while having parents with high education was slightly negative OR=1. 9 (Hestbaek L 2005)

Multiple Minor Risk Factors • A little bit of this, a little bit of

Multiple Minor Risk Factors • A little bit of this, a little bit of that • Do risk factors, add or compound ? A slightly bad neck and a crook back • No valid studies

What to Do ? • History (detailed or cursory ) • History + Exam

What to Do ? • History (detailed or cursory ) • History + Exam + XR (whole spine or Lx) • History +Exam+ XR + Further Imaging • History + Exam + Functional Matching (quantitative or qualitative job/physical characteristics ) • None of the Above

Strategies for Less than Ideal Math's • Identify Risk Factors as an awareness promoting

Strategies for Less than Ideal Math's • Identify Risk Factors as an awareness promoting exercise • • and Institute an early reporting system Consider, job matching trial (recall Harbin NNT=3) and/or Aggressive early intervention (secondary prevention) Avoiding, costly intervention on false positives, non effective intervention on true positives, or the stigma of non-hire (true or false positive) Employment exams as an Insurance policy, against fraudulent or excessive claims ?

Things To Re-Consider • Cost of Exams • Stigma to rejected applicants • Cost

Things To Re-Consider • Cost of Exams • Stigma to rejected applicants • Cost of interventions (primary or secondary) • Cost and Significance of Bad Outcomes • Potential Role of Exams as Part of Employee Care Program

Questions & Lively Discussion • Are other areas of the body better off ?

Questions & Lively Discussion • Are other areas of the body better off ? • How reliable/valid are cardiovascular risk factors ? • How to better integrate intrinsic and extrinsic risk factors ? • Most diseases are multi-risk generated ?