ergonomic pipette research

REDUCING THE RISK OF REPETITIVE STRESS INJURIES DUE TO PIPETTING

Richard Scordato

VistaLab Technologies, Inc.

Topics

• Background

• Pipetting Ergonomics

• A New Ergonomic Pipette Design

• Pipette Evaluations

• Questions

Is Pipetting Really an Ergonomic Risk?

Hire an Ergonomist!

Kevin Costello

Dennis Mitchel

What is Ergonomics?

Ergonomics is the science of work. The goal of

ergonomics is to remove barriers to quality, productivity

and human performance by fitting products, tasks and

environment to people

On a National Basis……

• Work-related musculoskeletal disorders (WMSDs) are the single largest job-related injury and illness problem in the United States

• WMSDs account for 34% of all reported illnesses and injuries, totaling 626,000 days away from work

• U.S. employers are currently paying in excess of $15 billion per year in workers compensation costs for WMSDs and associated expenses

-Occupational Safety and Health Administration (OSHA), November 14, 2000

The Ergonomics Literature

• Swedish Laboratory Workers1

- 44% reported hand problems

- 58% reported shoulder problems

- 44% reported neck problems

• U.S. Pipetting Study2

- Significant increases in hand & elbow injuries among pipette users

• National Institute of Occupational Safety & Health3

- “a biomechanical hazard exists from exposure to pipetting operations . . .”

1. MG Bjorksten et al, 1994; 2. G. David, P. Buckle, 1996; 3. NIOSH 1995

Injuries Attributed to Pipetting

Injuries Attributed to Pipetting

• VistaLab Survey

– 45% report at least occasional pain or discomfort while pipetting

Pipetting is the #1 cause of Musculoskeletal Disorders (MSD’s) in the laboratory

• Carpel Tunnel Syndrome (CTS)

• Tendinitis

• Epicondylitis (tennis elbow)

• Trigger Finger

• Tension Neck Syndrome

• Others

Injuries are Widespread

• Not just older Lab Workers

• Not just thumb and hand – Shoulder, neck, elbow and back

• Women more than men

Why does Pipetting Increase the Risk of Injury?

General Ergonomic Risk Factors

VibrationPersonal

Repetition

Environment

Posture

Contact Stress

Force

Risk Factors

Report: “An Ergonomic Disaster”

Pain: hands, wrist, elbow, shoulder and neck

• Considerable reaching resulting in repetitive upper arm flexion & abduction

• Unsupported arm and static muscle loading of the shoulder

• Cramped work space, especially under hoods

• Considerable amount of neck flexion

• Handling multiple objects

Report: “An Ergonomic Disaster”

Pain: hands, wrist, elbow, shoulder and neck

• Excessive finger flexor muscle during aspirating and dispensing

• Excessive force associated with tip attachment

• Pain /discomfort associated w/ tip attachment & tip eject effort levels

• The tip of the thumb is used almost exclusively

Axial Pipettes

• Design is over 40 years old

• Simplest & cheapest way to make a pipette

• The science of ergonomics was unknown when invented

Key Ergonomic Issues with Axial-Design Pipettes

• Pipette length requires user’s arm to be at an excessive height

• Narrow body shape requires a tight fist grip during use

• Excessive wrist flexion and arm supination required

• Excessive forces are required

Key Ergonomic Issues with Axial-Design Pipettes

• Poor tip fit

• High tipping & tip ejection forces

• High plunger forces

• Awkward volume adjustment

• Shape not fitted to the hand

Ergonomist’s Conclusion:

• Modification of the axial design does not meet the objectives

• A totally new design was needed

What Makes a Pipette Ergonomic?

General Ergonomic Risk Factors

VibrationPersonal

Repetition

Environment

Posture

Contact Stress

Force

Risk Factors

A Totally New Design Platform for Pipetting

• Non-axial structure

• Contoured shape

• Freestanding

• Adjustable hook

• Large contoured plunger

• Large functional buttons

The Ovation Design

• Positive tip acquisition

• Actuated tip removal

• Low plunger forces

• Electronic Volume Selection

• Volume Presets

Posture Comparison

Traditional pipettes Ovation

“Clenched Fist”

Increases stress, reducing available hand strength and diminishing productivity

Loose, Relaxed

Increases available strength in hand, improving endurance and productivity during

pipetting

Posture Comparison


Elevated, “Winged Elbow”

Arm/hand elevation exceeding 12” causes stress to the neck and shoulder

Close to work surface

Arm elevation remains low, minimizing stress to elbow, shoulder and neck

Posture Comparison

Over-rotated

Rotation exceeds 90º, causing stress to the wrist, hand and elbow. Arm Supinated

Neutral, Relaxed

Wrist remains in a neutral range of motion throughout all pipetting operations. Arm pronated


Reference: Rempel D, Bach J, Gordon L, Yuen S. Effects of Forearm Pronation/Supination on Carpal Tunnel Pressure. Journal of Hand Surgery 1998; 23A:38-42

. . . To Carpal Tunnel Syndrome

Awkward Posture is the Leading Contributor . . .

Ergonomic Performance

Carpal Tunnel Pressure

45 degrees pronation 0 degrees (vertical) 45 degrees supination

Reference: Rempel D, Bach J, Gordon L, Yuen S. Effects of Forearm Pronation/Supination on Carpal Tunnel Pressure. Journal of Hand Surgery 1998; 23A:38-42

17 mmHg 27 mmHg 39 mmHg

Ovation Evaluations

• ETC Ergonomist’s testing

• NIOSH

• Duke University

• Customer Feedback

Ergonomic Testing

EMG (electromyogram) testing as used to measure the activity of muscle groups used during pipetting.

Electrogoniometry is used to measure posture.

Example: Forces required by different pipettes to discard tips

Recommended limit 15% MVC35

30

25

20

15

10

5

0

OP

Flexor

Extensor

Ovation A B C DPipette

%M

VC (a

t ful

l str

engt

h)

Source: Ergonomic Technologies Corporation, Syosset, New York

What Does This Mean When Pipetting?

Example: uninterrupted full cycle measurement of wrist extension and flexion

AverageExtension

AverageFlexion

Ovation A B C D Pipette

Deg

ree

of w

rist f

lexi

on a

nd e

xten

sion

Recommended Limit

Recommended Limit



Example: arm flexion and extension during aspiration

Recommended limit

Recommended limit

20

15

10

5

0

-5

-10

-15

-20

MaxFlexion

Max Extension

Ovation A B C D PipetteD

egre

e of

arm

flex

ion

and

exte

nsio

n



Evaluation of the Effectiveness of a Re-designed Pipette for Reducing the

Risk Factors for Musculoskeletal Disorders

Ming-Lun (Jack) Lu, Ph.D.

Sunil Sudhakaran, M.S. AEP

March 24, 2005

National Institute of Occupational Safety & Health (NIOSH)

Objective

• To determine whether the re-designed pipette (i.e. ergonomic intervention) significantly reduces the MSD physical risk factors associated with pipetting

Data Collection

• Thumb and total finger forces using 19 FlexiForceTM sensors

• Outcome variables:

– Thumb force: force data of 2 sensors

– Total finger force: sum of force data of all 19 sensors

Data Collection (cont.)

• Wrist posture and forearm rotation using a twin axis electrogoniometer and a torsiometer

• Outcome variables:

– Wrist ulnar/radial deviation

– Wrist flexion/extension– Forearm

pronation/supination

Electrogoniometer

Data Collection (cont.)

• Shoulder elevation using video data analyzed with Multimedia Video Task AnalysisTM

software

– Outcome variable: shoulder elevation greater than 45°

Pick up pipette Pick up tip Aspirate Overblow Eject tip

Thu

mb

Forc

e (K

g)

0

1

2

3

4

5

Benchmate Eppendorf Ovation

AA

B

A A

B

A

B

A

AB

A

Thumb Force

Different letters indicate a significant difference (p<0.05)


Tot

al F

inge

r F

orce

(K

g)

0

2

4

6

8

10

12

14

16


AA

B

AA

BA

B

A

A

BA

C

C

A

B

A

Total Finger Force



Wri

st D

evia

tion

(D

egre

es)

0

5

10

15

20

25

30


A

A

B

A

B

A

A

B

A

A

A

A

B

A

AA

Wrist Deviation


Pick up pipette Pick up tip Aspirate Overblow Eject tipSho

ulde

r E

leva

tion

Gre

ater

than

45

degr

ees

(Per

cent

Tim

e)

0

20

40

60

80

100


A A

B

A

A

B

A

BA

A

BA

CA

A

A

Shoulder Elevation Greater than 45°


NIOSH Conclusion

• The re-designed, low force pipette showed a significant reduction in the most important MSD risk factors for pipetting, as compared to two other traditional axial-design pipettes

A Comparison of Traditional and Alternative Pipettes:

Comfort and Preference

Tamara James, MA, CPETamara James, MA, CPE

Ergonomics DirectorErgonomics Director

Duke University & Health SystemDuke University & Health System

Durham, North Carolina USADurham, North Carolina USA

Duke Study Summary

• “Overwhelming preference for Ovation in terms of Overwhelming preference for Ovation in terms of ‘Comfort’”‘Comfort’”

• ““Strong preference for Ovation in terms of ‘Accuracy’ Strong preference for Ovation in terms of ‘Accuracy’ and ‘General Use Throughout Workday’”and ‘General Use Throughout Workday’”

Cap Opener

• Study led to solutionStudy led to solutionaddressing specificaddressing specificproductivity issueproductivity issue

Cap Opener Cap Opener

VistaLab Surveys

• Random Sample of Customers

• Did you have pain or discomfort while pipetting?

Conclusions

• Ovation Design Uniquely Addresses Pipette Ergonomics

• NIOSH Study Supports Reduction of MSD Risk

• Duke Study Shows Greater Comfort and Preference

• Ovation Users Report Reduction in Pain and Discomfort

Pipette Ergonomics Focus Group

Questions?

ergonomic pipette research

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