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Pre-Employment Spinal Exams: Identifying Intrinsic Risk Factors

Explore the importance of pre-employment spinal exams in identifying intrinsic risk factors such as back pain, injuries, deformities, and more. This study by Dr. David McGrath in 2008 highlights the potential benefits in detecting and managing these risk factors to improve overall employment outcomes.

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Pre-Employment Spinal Exams: Identifying Intrinsic Risk Factors

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  1. Pre-Employment ExamsA Spinal Focus Spinal Intrinsic Risk Factors Dr David McGrath 2008 www.drdavidmcgrath.com.au

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

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

  4. Assessing the Risk(hypothetical non specific risk factor OR=17 )

  5. 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 )

  6. Detection(sensitivity 80%, specificity 77% )

  7. The Risk Adjusted Company(Perfect Intervention=All those identified with risk factor prevented from bad outcome NNT=2)First number indicates employees with risk factorSecond number indicates, employees without risk factor

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

  9. Company after Realistic Intervention (NNT=4)

  10. 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

  11. After Hiring another 28 in 139 exams total (excluding 39 candidates, only 11 of which have the risk factor, while 28 don’t )

  12. Comparing Outcomes

  13. 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)

  14. 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

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

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

  17. 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

  18. 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

  19. 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.

  20. 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

  21. 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

  22. 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)

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

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

  25. 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

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

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

  28. 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)

  29. 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”

  30. 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”

  31. 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

  32. 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 “

  33. 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)

  34. 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.

  35. 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.

  36. 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

  37. 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)

  38. 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

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

  40. 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 ?

  41. 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

  42. 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 ?

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