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Low Back Pain Development and Patient Handling

William S. Marras, Ph.D., CPEH d Ch i d P f d Di tHonda Chaired Professor and DirectorBiodynamics LaboratoryThe Ohio State UniversityColumbus, Ohio

http://biodynamics.osu.edu

National Statistics Relative to Patient Handling Risk

Lost time injuries in the U.S. in 2007 (BLS, 2008)1. Laborers & material movers (79,000 cases) 2. Heavy and tractor-trailer drivers (57,050 cases)3. Nursing aides, orderlies, and attendants (44,930 cases)

Musculoskeletal Disorder Rates in 2007 (BLS, 2008)( , )Highest National Rate - Nursing aides, orderlies, and attendants (252/10,000 workers) was 7x the National averageLaborers and freight handlers (149/10,000 workers)Delivery truck drivers (117/10,000 workers)

In 2007 the trunk was the body part most often injured accounting for 33% of all injuries and illnesses (BLS, 2008)

Low Back Pain (LBP) Statistics for Nurses

52 % of nurses complain of LBP (Nelson, 2003)12% of nurses leave the field because of LBP (Stubbs et. al., 1986)20% transfer to a different unit because of LBP (Owen, 1989)38% have LBP severe enough to have lost time (Owen, 2000)38% new LBP cases per year (Yip, 2004)

Recent Studies Indicating Low Back Pain Prevalence Work-related back pain in nursesHignett, S.(2008) J. Advanced Nursing 23(6), p. 1238-1246

LBP point prevalence = 17%LBP annual prevalence = 40-50%LBP lifetime prevalence = 35-80%

Recent Studies Indicating LBP Prevalence and Risk and Patient Handling

Low Back pain Among Nurses: A follow-up beginning at entry to the nursing schoolVideman, T., et al., (2005) Spine, 30(20), p. 2334

Followed 174 nursing students for 7.5 yearsFollowed 174 nursing students for 7.5 years1 year prevalence = 54% for 1st year students

= 57% for 1st year as nurse= 64% for 5th year as nurse

OR for LBP & Twisting = 6.2 (1.7-2.3) and LBP & Bending = 7.5 (2.9-20)OR for Sciatica = 6.9 (2.1-23)Conclusion – Lifetime prevalence of LBP increases sharply during nursing schoolNature of association is unclear but LBP is exacerbated during nursing

Low Back Surgery

“No operation in any field of surgery leaves in its wake more human wreckage than surgery on the lumbar discs” (DePalma and Rothman, 1970)

Surgical success rates for discectomy = 42.6% (vs. 32 4% non-operative) (Weinstein et al 2006)32.4% non operative) (Weinstein et. al. 2006)

Cost of treatment has increased 65% in 8 years (after adjusting for inflation) (Martin, et al., 2008)

Value of prevention

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What do We Know About Low Back Pain Causality?Low Back Pain Causality?

Risk Estimates for Work-Related Physical Risk Factors and Back Disorders

Risk EstimateNull Association

PositiveAssociation

AttributableFraction (%)

Physical Work-Related Risk Factor

n Range n Range n Range

Man al mate ial handling 4 0 90 1 45 24 1 12 3 54 17 11 66Manual material handling 4 0.90-1.45 24 1.12-3.54 17 11-66

Frequent bending and twisting 2 1.08-1.30 15 1.29-8.09 8 19-57

Heavy physical load 0 8 1.54-3.71 5 31-58

Static work posture 3 0.80-0.97 3 1.30-3.29 3 14-32

Repetitive movements 2 0.98-1.20 1 1.97 1 41

Whole-body vibration 1 1.10 16 1.26-9.00 11 18-80

(NRC/IOM, 2001)

Low Back Pain Risk Factors (NRC/IOM, 2001)

Physical FactorsBiomechanical LoadingBiomechanical / Physiologic Tolerance

Individual FactorsAge, Gender, etc.Pain PerceptionGenetic FactorsPsychological Factors

Psychosocial Factors and Organizational Factors

Job SatisfactionJob Monotony Job Control

Social & Org.Factors

IndividualFactors

Low Back Pain Risk Factor Environment

Factors Factors

Physical Factors

(NRC/IOM, 2001)

Physical Factorsy

Recent Surveillance Studies with Biomechanical ImplicationsA study of work stress, patient handling activities, and the risk of LBP among nurses in Hong KongYip, Y. (2001) J Adv Nurs, 36(6), 794-804

Prevalence = 40.6 for LBPOR for LBP & repositioning = 2.07OR for LBP & assistance during walking = 2.11

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Recent Studies with Biomechanical ImplicationsExpanded OSHA 300 log as metric for bariatric patient-handling staff injuries Randall, S. B., Pories, W. J., Pearson, A., Drake, D.J.(2009) Surg Obes Relat Dis, 5(4), p. 463-468

Patients with BMI > 35 = < 10% of patientsHandling patients with BMI > 35 associated with:

Turning and Repositioning patient implicated in: 31% of cases29.8% injuries27.9 % lost time37.2% restricted time

Usually performed using biomechanics and NOT equipment

Recent Studies with Biomechanical ImplicationsRisk Factors for LBP and Patient Handling of Nursing PersonnelLee, Y-H and Chiou, W-K(1994) J. Safety Research, 25(3) p. 135

1yr prevalence = 69.7 %Found lifting heavy objects, work experience, age, and sitting habits (together) have OR = 2.81 (1.88-4.20) for LBP Conclusion – Limit patient lifting to 47 Kg (104 lbs)

Physical Factors: Overexertion During Lifting (BLS, 2007)

40

50

60

70

80

0,0

00

fu

ll-ti

me

Hospitals

Nursing and

0

10

20

30

2003 2004 2005 2006

Rat

e pe

r 1

Year

Nursing and Residential Care Facilities

The cumulative weight lifted by a nurse in one typical 8-hour shift is equivalent to 1.8 tons (Tuohy-Main, 1997).

oad

Risk of InjuryRisk of Injury

Biomechanical Logic:Load – Tolerance Relationship

Time

Spin

al L

o

Tolerance

Loading Pattern

(McGill, 1997)

Intervertebral Disc

The primary source of low back pain is suspected to be the disc (Nachemson, 1976; Videman and Battie, 1996; An, 2004)

Noxious stimulation of the disc produces symptoms of low back painlow back pain Annular tears and reduced disc height are associated with low back pain (Videman et. al., 2003)

Mechanical load can be the stimulus for pain (Marras, 2000)

How Cumulative Trauma Develops in the Spine

Vertebral Endplate

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Disc Nutrition Pathways

Vertebral Body

Vertebral Endplate

Disc

How Cumulative Trauma Develops in the Spine

Vertebral Endplate

Mi f tMicrofractures

How Cumulative Trauma Develops in the Spine

Vertebral Endplate

S TiScar Tissue Development

Disc Degeneration and Cumulative Trauma

Vertebral Body

Vertebral Endplate

Disc

Scar Tissue

CompressionSpine Tolerance Limits

3400-6400 N Limit (NIOSH, 1981)

Anterior/Posterior(A/P) Shear

Lateral Shear1000 N Limit(McGill, 1994; Yingling 1999)

1000 N Limit (Miller, 1986)

Endplate Compression Tolerance

(Jager and Luttmann, 1991)

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5

6000

8000

10000

12000

s to

Fai

lure

(Gallagher, et al., 2003)L5/S1 Cyclic Tolerance

0

2000

4000

0 degrees 22 degrees 45 degrees

Cyc

les

Torso Flexion Angel

Recent Studies with Biomechanical ImplicationsDose-response relations between occupational exposures to physical and psychosocial factors and the risk of low back painJansen, J. P., Morgenstern, H., and Burdorf, A. (2004) Occup Environ Med 61 p 972-979(2004) Occup Environ Med, 61, p. 972 979

Followed 523 patient handlers in nursing homes in The Netherlands prospectively over 1 yearQuantitatively monitored patient lifting and observed new LBP episodesTrunk flexion over 45 deg association with LBP riskOR = 3.18 (1.13-9.00)

Spine Loading During Patient HandlingPatient Handling

Biomechanical Modeling of the Low Back

Can we assess specific spine tissue loads?

Low Back Pain: Understanding Back Function

Internal Force

External Force

Spine Loads Results from the Reaction of Internal Forces to External Forces

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0 6

0.8

1.0

1.2

1.4

Mus

cle

Act

ivity

%

MVC

)

Trunk Muscle Coactivity

0.0

0.2

0.4

0.6

LLT RLT LES RES LAB RAB LEO REO LIO RIO

Max

imum

( %

LBP Group Asymptomatic Group

(Marras et al., 2005)

Single Equivalent Multiple Muscle Model Muscle Model

Biologically Assisted (EMG)-Assisted Biomechanical ModelsModels

The OSU Biodynamic Model

The Control System

Laboratory Assessment of Push-Pull

Assessment of Spine Forces Based Upon Task

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Spine Loads at Different LevelsSpecific Tissue Loads with Inclusion of Finite Element Analysis

Patient Specific Anatomy Our Early Patient Lifting Studies

Patient Lifting Origins/Destinations

Bed to/from wheelchair with armsBed to/from wheelchair with one arm removedPortable commode chair to/from hospital chair/ p

Transfer Techniques

1 person hug2 person hook and toss2 person gait belt

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Repositioning TechniquesSpine Compression as a Function of Transfer Task

6000

7000

8000

9000

ion

Forc

e (N

)

MaximumTolerance

2000

3000

4000

5000

Wheelchairw/o Arms –Bed

Wheelchair- Bed

Bed –Wheelchair

Chair -Commode

Transfer Task

Com

pres

s

One-Person Two-Person

Safe Limit

Bed –wheelchair w/o Arms

Commode- Chair

Spine Compression as a Function of Transfer Technique

5000

6000

7000

8000

9000

essi

on F

orce

(N)

Tolerance Maximum

2000

3000

4000

Hug HOOK BELT HOOK BELT

Com

pre

Safe Limit

Transfer Technique

Left Side Right SideOne-Person2 person 2 person

Spine Compression as a Function of Repositioning Technique

6000

7000

8000

9000

10000

11000

12000es

sion

For

ce (

N)

MaximumTolerance

2000

3000

4000

5000

Hook Hook Thigh &Shoulder

Sheet Hook Thigh &Shoulder

Sheet

Repositioning Technique

Com

pre

Left SideTwo Person

Right SideTwo Person

One Person

Safe Limit

Biodynamics Laboratory Previous Studies

Risk associated with one- or two- caregiver patient lifting

Conclusion - There is no safe way to lift patient manually! - The magnitude of spine loading is so great any

benefits of using proper body mechanics is negligible g p p y g g

Suggestion – Must employ patient lifting assistance device

Intervention Effectiveness (prospective observation of 100 units)

Patient Handling Interventions

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Patient Handling Musculoskeletal Disorder Rate Changes (#MSDs/employee-hours worked)*200,000

Type of Intervention

n Baseline median(Range)

Follow-up median(Range)

Rate Ratio (FU/BL MSD rate)

Reduce Bending

16 9.89(0.0-42.65)

6.65(0.0-59.51)

.66

Zero Lift 44 15.38(0.0-87.59)

9.25(0.0-28.27)

.54

Reduce Carrying

8 6.47(0.0-15.80)

0.33(0.0-6.70)

.15

Multiple Interventions

32 11.98(0.0-60.34)

7.78(0.0-25.94)

.56

All 100 12.32(0.0-87.59)

6.64(0.0-59.51)

.52

(Fujishiro, et al. 2005)

Patient Handling Change in MSD Rates per Intervention (baseline to follow-up)

Type of Intervention

# Units Decreasedor no change

Number of Units Increased

P-value

Reduce Bending

12 (75%)

4 (25%)

0.056

Zero Lift 32 (72.7%)

12 (27.3%)

0.002

Reduce Carrying

7 (87.5%)

1(12.5%)

0.031

MultipleInterventions

26(81.3%)

6 ( 18.7%)

0.001

All 77(77.0%)

23(23.0%)

<0.001

(Fujishiro, et al. 2005)

Our Previous Studies

Risk associated with one- or two- caregiver patient lifting Conclusion - There is no safe way to lift patient manually!Suggestion - Employ Patient Lifting assistance device

Intervention Effectiveness (prospective observation of 100 units)observation of 100 units)

Conclusion – Often observe significant reduction in riskNot all interventions created equally!27% of zero lift interventions had increased reporting

Lifting Transformed into Pushing and Pulling

Pushing and Pulling Research Question

Does changing patient handling from a lifting activity to a pushing activity eliminate the risk to the caregiver?

Is there a difference in pushing ceiling mounted vs. floor based patient lifting devices?based patient lifting devices?

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Pushing/Maneuvering Patients ApproachUse OSU Personalized Biodynamic Model to realistically assess spine loads when pushing patient with ceiling lifts vs. floor-based lifts

TaskTask

Push a patient lifting device through a course that contains many of the typical challenges within a health care facility

Experimental ConditionsLift system

Ceiling basedFloor based

large wheel vs. small wheelLarge wheels (5 inch diameter rear; 4 inch diameter front)Small wheels (3 inch diameter rear; 2 inch diameter front)

Floor surface Hard floor Carpet (short pile)

Patient weight125 lb (56.8 Kg)160 lb (72.7 Kg)360 lb (163 Kg)

Course control requiredStraightSharp (90 deg) turnGradual turnSharp turn in confined space (bathroom)

Patients

Patient weight125 lb (56.8 Kg)160 lb (72 7 Kg)160 lb (72.7 Kg)360 lb (163 Kg)

Course Path and Required Control

GRADUAL TURN

BATHROOM

CONFINED TURN

STRAIGHT SHARP TURN

START

END

NOTE: All dimensions are in inches

Course Path and Required Control

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Ceiling Lift Trial and Analysis Floor Based Lift used on Carpet

Floor Based Lift used on CarpetResults:

Spine Load Magnitudes

20003000400050006000

mpr

essi

on (N

)

Compression as a Function of Vertebral Level

010002000

L5/S

1 Infe

rior

L5/S

1 Sup

erior

L4/L5

Infer

ior

L4/L5

Superi

or

L3/L4

Infer

ior

L3/L4

Superi

or

L2/L3

Infer

ior

L2/L3

Superi

or

L1/L2

Infer

ior

L1/L2

Superi

or

T12/L

1 Infe

rior

T12/L

1 Sup

erior

Com

400600800

100012001400

tera

l She

ar (N

)

Lateral Shear as a Function of Vertebral Level

0200La

t

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600800

100012001400

Shea

r (N

)

A/P Shear as a Function of Vertebral Level

0200400

L5/S

1 Infe

rior

L5/S

1 Sup

erior

L4/L5

Infer

ior

L4/L5

Superi

or

L3/L4

Infer

ior

L3/L4

Superi

or

L2/L3

Infer

ior

L2/L3

Superi

or

L1/L2

Infer

ior

L1/L2

Superi

or

T12/L

1 Infe

rior

T12/L

1 Sup

erior

A/P

S

Significant Effects Lateral Shear

Compression A/P Shear

Patient Handling System (System)

0.003* 0.015* 0.060

Patient Weight (Weight) 0.124 0.069 0.057

R i d C t l 0 006* 0 105 0 005*Required Control over System (Control)

0.006* 0.105 0.005*

System*Weight 0.015* 0.189 0.133

System*Control 0.106 0.002* 0.001*

Weight*Control 0.496 0.695 0.497

System*Weight*Control 0.154 0.081 0.070

L3 A/P Shear a Function of Required Control

600800

100012001400

hear

(N)

0200400600

Straight Gradual Turn Sharp Turn Bathroom

A/P

Sh

Required Control

* Significant (p<0.005)

800

1000

1200

1400

r (N)

. Straight

Gradual Turn

L3 A/P Shear as a Function of System and Required Control

Required Control

0

200

400

600

800

Ceiling Lift Floor Based Systems

A/P

Shea

Gradual Turn

Sharp Turn

Bathroom

* Significant (p<0.001)

1000

1200

1400

N) . Straight

L3 A/P Shear as a Function of Lift System, Floor, and Required Control

Required Control

0

200

400

600

800

Ceiling Lift Carpet Hard Floor

A/P

Shea

r (N g

Gradual Turn

Sharp Turn

Bathroom

800

1000

1200

1400

r (N

) . Straight

L3 A/P Shear as a Function of System Wheel Type and Required Control

Required Control

0

200

400

600

800

Ceiling Lift Small Wheel Large Wheel

A/P

She

ar Gradual Turn

Sharp Turn

Bathroom

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80010001200140016001800

She

ar (N

) .

Straight

Gradual Turn

Sharp Turn

L3 A/P Shear as a Function of Floor Based Systems and Required Control

Required Control

0200400600

Ceiling Lift

Sm Wheel Carpet

Sm Wheel Floor

Lg Wheel Carpet

Lg Wheel Floor

A/P

S

Bathroom

* Significant (p<0.001)

Discussion

Ceiling lifts impose lowest (and safest) load on the spineNo risky conditions were identified for this condition

Floor-based lifts can impose significant biomechanical risk to spine but depends upon conditions of useRisk occurs primarily to the upper lumbar vertebrae (L3Risk occurs primarily to the upper lumbar vertebrae (L3 and above)

Previous studies have not studied those levelsMay help explain the 27% of LBP associated with pushing and pulling

These results may explain why interventions are not always effective

DiscussionA/P shear is mechanism of risk when pushing patientsFloor based risk increases with increased required control

Controlling lift in confined space (bathroom) poses greatest riskTurning (gradual or sharp turn) poses next greatest riskPushing without turning has minimal risk (but greater than ceiling lift)No increased risk with ceiling lift as a function of control

Operating floor based lifts on carpet or with small wheels greatly magnifies risk

Small wheels and carpet together create hazardous conditions when control is required.

800100012001400

ar (N

) .

L3 A/P Shear as a Function of Patient Weight

0200400600

125 lbs 160 lbs 360 lbs

A/P

She

Patient Weight

*Not statistically significant

Obesity Trends Among U.S. Adults between 1985 and 2008Obesity Trends Among U.S. Adults between 1985 and 2008

Definitions:Obesity: Having a very high amount of body fat in relation to lean body mass, or Body Mass Index (BMI) of 30 or higher.

Definitions:Obesity: Having a very high amount of body fat in relation to lean body mass, or Body Mass Index (BMI) of 30 or higher.

Body Mass Index (BMI): A measure of an adult’s weight in relation to his or her height, specifically the adult’s weight in kilograms divided by the square of his or her height in meters.

Body Mass Index (BMI): A measure of an adult’s weight in relation to his or her height, specifically the adult’s weight in kilograms divided by the square of his or her height in meters.

(CDC , 2010 U.S. Obesity Trends 1985-2008)

1999

Obesity Trends* Among U.S. AdultsBRFSS, 1990, 1999, 2008

(*BMI ≥30, or about 30 lbs. overweight for 5’4” person)

1990

2008

No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%

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Social & Org.Factors

IndividualFactors

Low Back Pain Risk Factor Environment

Factors Factors

Physical Factors

Non-Physical Factors Affecting Spine Loading:

Individual & P h i l F tPsychosocial Factors

Study Procedure

1. Un-Stressed Session - Perform Lift Tasks

The Influence of Psychosocial Stress, Gender, and Personality on Mechanical Loading of the Lumbar Spine (Marras et al., 2000)

2. Experiment Interruption / Experimenters Called Out of Room

3. Stressed Session - Perform Same Lift Tasks

Variability of Biomechanical Responses to Psychosocial Stress (Marras et al.2000)

30

50

70

90re

ssio

n Fo

rce

Uni

t Mom

ent

(N/N

m)

10

30

1 4 6 8 10 12 14 16 19 21 23 25

Subject Number

Com

prPe

r U

Unstressed Stressed

Differences in Spinal Loads Between Personality Traits in Response to Psychosocial Stress (Marras et al., 2000)

20

25

30

e

0

5

10

15

Extraverts Introverts

CompressionLat Shear

% I

ncre

ase

Differences in Spinal Loads Between Personality Traits in Response to Psychosocial Stress (Marras et al., 2000)

20

25

30

e

0

5

10

15

Sensors Intuitors

CompressionLat Shear

% I

ncre

ase

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Musculoskeletal Control and Tissue Load

Agonist Contraction

Antagonist Contraction

Antagonist Cocontraction Leads to Increased Tissue Load

Working with Low Back Pain

10

15

20

25

pres

sion

For

ce p

er

Mom

ent (

N/N

m)

0 3

0.4

0.5

0.6

0.7

0.8

al S

hear

For

ce p

er

Mom

ent (

N/N

m)

The Effects of Working with Low Back Pain Spine Loading

0

5

LBP Group Asymptomatic Group

Peak

Com

pSa

gitta

l

0

0.1

0.2

0.3

Peak

Lat

erSa

gitta

l

Compression Force Lateral Shear Force

(Marras, et al., 2005)

3000

4000

5000

6000

7000

8000m

pres

sion

For

ce (N

)

Dynamic Spine Loading

0

1000

2000

Region of Lift OriginLBP Group Asymptomatic Group

Peak

Com

(Marras, et al., 2005)

ConclusionsThere is no safe way to lift a patient manually (loads are too great for body mechanics to make a difference)There is surveillance evidence that interventions can help control riskLifting devices can help but the degree of control required greatly influences riskq g yUse ceiling lifts if at all possibleWhen using floor mounted lifts –

Use extreme caution when turning and controlling patient within the bathroom (this is where the risk occurs)Use extreme caution when using these systems on carpetDon’t use small wheels with floor based systems!

ConclusionsLow back forces and pain are initiated by spine loading due to A MIX OF:

Physical WorkPsychosocial and OrganizationalIndividual Factors

f k l h kAppreciation for trunk muscle coactivity is the key to understanding loading conditions

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Concern for man and his fate must always form the chief interest of all technical endeavors...

Never forget this in the midst of your diagrams and equations

- Albert Einstein

Thank You!

W b it htt //bi d i dWebsite: http://biodynamics.osu.edue-mail: marras.1@osu.edu