Occupational Medicine Prof. Francesco S. Violante

1. Occupational MedicineProf. Francesco S. Violante Musculoskeletal Disorders due to Biomechanical Overload

2. RSI: National Occupational Health and Safety Commitee, 1990 • “Occupational overuse syndrome, also known as Repetition Strain Injury (RSI), is a collective term for a range of conditions characterized by discomfort or persistent pain in muscles, tendons and other soft tissues, with or without physical manifestations. Occupational overuse syndrome is usually caused or aggravated by work, and is associated with repetitive movement, sustained or constrained postures and/or forceful movements. Psycho-social factors, including stress in the working environment, may be important in the development of occupational overuse syndrome”.

3. Ramazzini (1713) : De morbis artificum diatriba • “Due sono secondo me, le cause che provocano le varie e gravi malattie dei lavoratori: la prima è rappresentata dalle proprietà delle sostanze impiegate che, producendo gas e polveri tossiche, inducono particolari malattie; la seconda è rappresentata da quei movimenti violenti e da quegli atteggiamenti non naturali per I quali la struttura stessa del corpo ne risulta viziata, cosicché col tempo sopraggiungono gravi malattie.”

4. Names of Muskuloskeletal disorders • Work Related Musculoskeletal Disorders (WRMSD) • Cumulative trauma disorders (CTD)‏ • Repetitive trauma disorders • Repetitive strain injuries (RSI)‏ • Occupational Overuse syndromes • Occupational cervicobrachial disorders • Musculoskeletal Pain/Symptoms • (…)‏

5. Properties of Musculoskeletal Disorders • WRMSD is not a diagnosis! It is a name used for a group of disorders that share some common qualities: • Mechanical and physiological process • Related to work intensity and duration • Require periods of weeks, months or years to develop • Require periods of weeks, months or years for recovery • Poorly localized, nonspecific and episodic • Often unreported • Multiple work and personal causes

6. WHO, 1985 • The World Health Organization has characterized “work-related” diseases as multi-factorial to indicate that a number of risk factors (e.g., physical, work organizational, psychosocial, individual, and sociocultural) contribute to causing these diseases (WHO 1985). • There is disagreement, however, on the relative importance of occupational and individual factors in the development of work-related illnesses. The same controversy has been an issue with other medical conditions (occupational and non-occupational) such as certain cancers and lung disorders, both of which have multiple causality.

7. Risk Factors

8. Personal CTD Factors • Gender • Age • Obesity • Pregnancy • Rheumatoid arthritis • Oral contraceptives • Endocrinological disorders, e.g., diabetes • Acute trauma, e.g., bruises, burns, lacerations • Vitamin B-6 deficiency • Gynecological surgery, e.g., oophorectomy, hysterectomy • (Wrist size and shape) • (Fitness)‏

9. LBP and Individual Risk Factors • Age • Female sex (risk 40-57%)‏ • Height: although some studies reported a higher risk in taller subjects, most research does not support this • Weight: increased risk in overweight/obese subjects • Previous LBP episodes: seem to be associated with future episodes • Predisposing disorders: may have a role in the onset of occupational low back pain, but some of them are relatively rare (e.g. spondilolistesis)‏

10. LBP and Individual Risk Factors • Smoking: it was considered as a possible risk factor (although there are many other factors that can be related to cigarette smoking: socioeconomic class, lifestyle…), but according to Leboeuf-Yde's revision(Spine 1999, 24(14) 1463-70) it is rather to be considered as a weak risk indicator than as a real causal factor • Alcohol: although there is no evidence of a positive association, this cannot be excluded due to the lack of informative studies in this field (Leboeuf-Yde C. Alcohol and low-back pain: a systematic literature review. J Manipulative Physiol Ther. 2000;23(5):343-6)‏

11. LBP and Individual Risk Factors • Education: when evidence of association between LBP and low educational level exists, we need to evaluate its dependence on socioeconomic status (review by Dionne et al., J Epidemiol Community Health. 2001;55(7):455-68)‏ • Sport: Although the lack of sufficiently informative studies, data support the positive association between sedentary activity (and intense physical exercise) and LBP (review by Hildebrandt et al. Int Arch Occup Environ Health, 2000;73:507-518)

12. LBP and Psychosocial Factors • Work Organization (production rates, timetables, control and test systems)‏ • Relationships with colleagues and superiors

13. LBP and Psychosocial Factors • Workload perception, organizational aspects, work social support: (moderate evidence of) no association • Stress: weak evidence of a positive association (systematic review of the literature, Hartvigsen et al, Occup Environ Med 2004; 61(1):e2)‏ • Stress, depression and somatization increase the risk of LBP chronicity(review by Pincus et al. Spine 2002 Mar 1;27(5):E109-20)and also seem to play an important role in the patho-genesis of the acute event (review by Linton, Spine 2000 25(9):1148-56)‏

14. LBP and Occupational Risk factors • MHL (manual handling of loads): any transporting or supporting of a load, by one or more workers, including lifting, putting down, pushing, pulling, carrying or moving of a load • Vibrations transmitted to the whole body • Flexions and torsions • Maintenance of fixed postures for prolonged periods (repetitive manual work)‏

15. Fattori di rischio professionali (AASS)‏ • High-frequency repetitive movements • Movements requiring the use of force • Awkward postures • Localized compressions • Vibrations • Other factors: low temperatures, absence of adequate recovery times

16. Hand/Wrist CTS Strong Evidence (+++)‏ Evidence (++)‏ Insufficient Evidence (+/0)‏ Repetitiveness X Force X Posture X Vibrations X Combination X Evidence of Relation between Biomechanical Risk factors and WMSDs - NIOSH (Bernard,1997)‏

17. Hand/Wrist Tendonitis Strong Evidence (+++)‏ Evidence (++)‏ Insufficient Evidence (+/0)‏ Repetitiveness X Force X Posture X Combination X Evidence of Relation between Biomechanical Risk factors and WMSDs - NIOSH (Bernard, 1997)‏

18. Elbow Strong Evidence (+++)‏ Evidence (++)‏ Insufficient Evidence (+/0)‏ Repetitiveness X Force X Posture X Combination X Evidence of Relation between Biomechanical Risk Factors and WMSDs - NIOSH (Bernard, 1997)‏

19. Shoulder Strong Evidence (+++)‏ Evidence (++)‏ Insufficient Evidence (+/0)‏ Repetitiveness X Force X Posture X Vibrations X Evidence of Relation between Biomechanical Risk Factors and WMSDs - NIOSH (Bernard, 1997)‏

20. Lombalgia Strong Evidence (+++)‏ Evidence (++)‏ Insufficient Evidence (+/0)‏ MHL (Manual Handling of Loads)‏ X Flexion/Torsion of trunk X Posture X Vibrations* X * Vibrations transmitted to the whole body (Whole body vibration)‏ Evidence of Relation between Biomechanical Risk Factors and WMSDs - NIOSH (Bernard, 1997)‏

21. MHL and Awkward Postures

22. Rachis Posture: examples

23. Musculoskeletal Disorders in Europe (European Foundation, Dublin, 2000)‏ Third Survey on Workers' Health: • 33 % report backache • 28 % report stress disorders • 23 % report shoulder and neck pain • 13 % report upper limb pain

24. Percentage of workers reporting each individual symptom (European Foundation 2005)‏

25. Incidence of ODs Recognised by INAIL in the Years 1995-1999 within the Industry Sector

26. WRMSDs granted by SMG (incidence rate by type of disorder)‏ WRMSDs sent to SMG (distribution by region)‏ INAIL DATA, 2000

27. Mounting, Assembly 43,4 Clothing Industry 7,3 Meat Processing 5,8 Sorting/ Selection 5,2 Confection/ Packaging 4,7 Wood Smoothing 4,4 Driving of Mechanical Vehicles 4,4 Footwear and Leather Industry 4,1 Other 20,7 Inail Data, 2000: % of Recognized MSDs by Work Process

28. INAIL - % of MSDs by type of disorder

29. INAIL - % MSDs by age

30. Low back pain, LBP • 80% of the population suffer from LBP at least once in their lifetime • 50% of cases resolve within 4-8 weeks • 85% of relapses • The first episode generally occurs between 20 and 40 years of age and affects both sexes (Hicks GS, et al. Am J Med Sci 2002; 324: 207-211)‏

31. USA: Top 10 Most Costly Physical Conditions (by component)‏ (Goetzel RZ, et al. JOEM 2003: studio riguardante più di 370.000 lavoratori americani)‏

32. Workers at risk of Low Back Pain • Health Personnel (nurses, physical therapists, health operators and assistance technicians) are considered among the most at-risk categories for Low Back Pain; the manual handling of patients is the major source of risk • Load Handling Personnel (building sector, portering, foundry, agriculture, store activities, product arrangement)‏ • Drivers of Heavy Vehicles

33. EXPOSURE TO BIOMECHANICAL RISK FACTORS ADAPTATION (TRAINING EFFECT)‏ DAMAGE (MUSCULOSKELETAL DISORDER)‏ Musculoskeletal Disorders due to Overload: Physiopathogenesis • Reaction 1 • Reaction 2 • Reaction 3 • Reaction 4 • …

34. Possible Mechanisms involved in the development of WR- fatigue and pain

35. Shoulder: Anatomical Hints

36. Shoulder: Main Disorders • Acute Tendonitis • Tendinosis (with/without calcification)‏ • Rotator cuff lesions/ruptures • Bursitis • Conflict Syndromes • Arthrosis • (Scapulo-humeral Periarthritis ??!!)‏

37. Elbow: Anatomical Hints Elbow and Forearm Pain Diagram

38. Flessori Estensori Elbow: Main Disorders • Epicondylitis • Medial Epicondylitis • Olecranon Bursitis • Compression of the ulnar nerve at the elbow

39. Hand: Anatomical Hints

40. Hand: Anatomical Hints

41. Hand: Main Disorders • Tenosynovitis of the carpal and finger extensors/flexors • De Quervain's Syndrome • Trigger Digit • Carpal Tunnel Syndrome • Guyon's Canal Syndrome • Ganglion Cysts

42. De Quervain's Syndrome • Inflammation of the tendon sheaths of the abductor pollicis longus and extensor pollicis brevis • Pain is increased by ulnar deviation of the wrist • Finkelstein sign

43. Trigger Digit • Tendon nodule at the metacarpal-phalangeal level associated with deficit in digit extension due to purely mechanical factors

44. Carpal Tunnel Syndrome • Clinical condition caused by the compression of the median nerve at the carpal tunnel (focal compression neuropathy), which manifests as tingling, numbness sensation, soreness, pain involving at least one of the first three fingers

45. Musculotendinous Disorders of the Upper Limb: diagnosis • Clinical: • Symptoms: pain, difficulty sleeping on the affected side • Signs: Clinical tests and specific provocative tests - e.g. Finkelstein – active, passive and against-resistance mobilizations • Functional limitation • Diagnostic Imaging (US, XR, MR)‏ • Laboratory Tests can help determine the etiology of these disorders

46. Diagnosis of CTS and other Peripheral Neuropathies • Clinical: signs and symptoms (paresthesias, Tinel's and Phalen's tests)‏ • Electrodiagnostic tests are useful to confirm diagnoses and estimate severity • Further tests: ultrasound scan, laboratory tests, XR tests can help determine the etiology of these disorders

47. US: Longitudinal Section of the Wrist

48. US: Cross Section of the Wrist

49. Cross-sectional MR of the Wrist

50. ARTROSI COMPRESSIONE NERVOSA ERNIA Rachis: Most Frequent Disorders • Intervertebral Disc Degeneration progressive thinning of cartilage with consequent loss of shock absorbing function • Arthrosis (radiculopathy) degenerative disease of the bone leading to the formation of osteophytes • Herniated Disc (radiculopathy) condition due to the degeneration or acute rupture in the fibrous ring of the intervertebral disc with consequent migration of the nucleus pulposus to the periphery