Download noise-induced hearing loss in orthopaedic staff

NOISE-INDUCED
HEARING
LOSS
K.
In the
light
of EEC
proposals
M.
From
Charing
on the
avoidance
IN
ORTHOPAEDIC
STAFF
WILLETT
Cross
Hospital
of damage
to hearing
caused
by noise,
a study
was
undertaken
to determine
the risk posed by powered
orthopaedic
instruments.
The noise levels from a number
of air-powered
and electric
tools were measured
and analysed
and found to exceed
the recommended
levels.
The predicted
daily personal
noise exposure
was calculated
and the potential
for hearing
damage
confirmed.
Twenty-seven
senior
orthopaedic
loss was found in half the subjects.
The increasing
staff
use of powered
were
then
instrwnents
assessed
by audiometry;
in elective
orthopaedics
significant
cumulative
risk to the hearing
of orthopaedic
defenders
should
be promoted,
and manufacturers
should
noise emission
levels.
It
is recognised
that
suffer
permanent
in the use of
workers
hearing
powered
in
noisy
damage.
instruments
The
industries
increase
elective
provide
sources
orthopaedic
and fracture
surgery
could
of such noise. This has been investigated.
A consultative
Commission
the prevention
document
from
the Health
(1987)
proposed
new
of damage
to hearing
may
steady
in both
safety
from
and
Safety
noise
damage.
various
surgical
Noise-induced
tone
of noise-induced
and fracture
surgeons
and
be encouraged
paedic
theatres
standards
for
noise at work;
evidence
fixation
personnel,
for at least
audiometry
each
having
worked
in
five years,
were investigated
using
a ‘quiet
consultants,
four senior
and five plaster
technicians.
subjective
awareness
was always
performed
MATERIALS
Noise
emission
AND
levels.
Using
Adminis-
exposure
threshold
METHOD
a sound
level
meter
the level
For
(decibels,
ofexposure
ofother
each
instrument
dB(A)),
the peak
peak noise (dB) were
produces
a frequency
human
ear
and
personnel
in the theatre.
the A-weighted
noise
level
noise frequency
(Hz) and the
recorded.
response
is used
for
The A-weighted
similar
to
measurements
network
that
of the
of the
risk
of
to instrument
noise
shift phenomenon.
©
Registrar
W2 1NY,
1991 British
Editorial
Society
ofBone
and
030l-620X/9l/1018
$2.00
JBoneJoint
Surg[Br]
1991 ; 73-B:l 13-15.
VOL.
73-B,
No.
1, JANUARY
1991
Joint
England.
Surgery
operating
by pure
There
two
were
theatre
16
sisters,
sensitivity.
a 24-hour
to prevent
Audiometry
absence
from
any
temporary
RESULTS
Most orthopaedic
drills and saws produced
noise
levels
of between
90 and 100 dB at the operator’s
ear (Table
I).
The noise level recorded
at 3 m was significantly
less (the
Table
I.
instrument
Instrument
(number
Air powered
Power drill
noise
tested)
(4)
Reciprocating
Reciprocating
K. M. Willett,
FRCS,
Senior
Orthopaedic
St. Mary’s
Hospital,
Praed
Street,
London
a
an extensive
‘noise
history’
work
exposure,
to exclude
ear disease,
and to assess
of hearing
after
(Braul
and
Kjaer
type
2209)
and
an Octave
band
analyser
(Octave
filter
type
1616),
recordings
were
made
in an
operating
theatre
of the noise emission
levels of various
air-powered
and electric
drills and saws.
The noise was
sampled
at the operator’s
ear, and at a distance
of 3 m,
room’.
registrars,
the American
tration
hearing
Health
present
use of ear
with lower
The cumulative
times
of use of drills
in
procedures
was also recorded.
hearing
loss. A total of 27 senior
ortho-
Each subject
completed
questionnaire
to determine
previous
noise
damage
and
Safety
and
programme.
may
theatre
personnel.
The
to develop
instruments
these were implemented
in January
1990. ‘Action
levels’
of noise
exposure
are defined
and legislation
will be
introduced.
These
levels
are similar
to those
defined
by
Occupational
conservation
hearing
saw (3)
saw (4)
Multihead
drill, small (2)
Multihead
drill, large (3)
Airtome/dental
burr (2)
Electric
powered
Plaster
saw, type
Plaster
saw, type
I (4)
2 (7)
emission
Noise
emission
dB(A)
90
95
95
92
90
80
to
to
to
to
Peak
frequency
Hz
Room
noise level
3m dB (A)
5000
82
85
88
86
84
76
100
100
4000
4000
95
92
2500
1400
6000
95 to 100
95 to 105
4300
3500
80
84
113
K. M. WILLETr
114
decibel
drills
scale
is logarithmic).
are given
The daily
calculated,
exposure
Health
in Table
personal
Typical
II.
noise
exposure
and is proportional
and to the A-weighted
and
Safety
the first level
daily personal
periods
of use
(LEP,d)
can
to the daily duration
sound
pressure.
Commission
recommendation
of noise
exposure
deemed
noise exposure
of 85 dB.
excluded
: one
for
ear
for hearing
disease,
two
because
five were
of wartime
compared
normal
to sexpopulations
Total
ing
normal
Data
being
for 27 subjects
with
a minimum
Mean
replacement
from
perception
Examples
of
of both
2.
There
suggestive
types
the
was audiographic
of noise-induced
75
4
375
4
are
loss
of
(%)
by
sounds,
Hz, and
frequency
the
the
the
sounds.
illustrated
evidence
hearing
in Figures
which
was highly
loss in 1 1 of the 22
(Table
III). The number
of years
of potential
seemed
to be a common
factor
in those affected,
one subject
complained
of tinnitus
and this was
recent
exposure
(yr)
Noiseinduced
hearing
Age
Exposure
16
4
47
22
4
8
4
0
36
0
0
Theatrenurses
2
1
41
13
1
0
Plaster
5
0
46
22
3
3
technicians
15
in
1 and
Exduded*
registrars
617
highest
Number
Senior
3
age-related
of loss
use
Proportion
operation
of the low frequency
loss at 3000 to 6000
Subjective
deafness
Consultants
instrument
190
hip screw
is distinguished
of five years
HI.
powered
offemur
preservation
‘notch’
peak
Table
audiograms
nailing
knee
loss
relative
typical
age-related
figures
for otologically
(Shipton
1979). Noise-induced
hear-
individual
and
Dynamic
subjects
exposure
but only
minor.
audiologist,
of
hip replacement
Intramedullary
noise exposure,
one for firearm
use, and one because
of
audiometric
evidence
of other
significant
ear pathology.
The results
for the other
22 subjects
are shown
in Table
III.
The
pure
tone
audiograms
were
interpreted
by a
consultant
Total
defines
loss,
duration
Duration
(see)
of
The
unsafe
to be a
This level would
assessed
II. Mean
operations
be
be reached,
for example,
by exposure
to noise of either
95 dB(A)
for 45 minutes
per working
day or 100 dB(A)
for 15 minutes
per day. The results
show that orthopaedic
operators
may suffer potentially
damaging
levels of noise
exposure,
but that theatre
attendants
are probably
not at
risk.
Of the 27 subjects
Table
various
of
5.7
loss
*see text
FREQUENCY
FREQUENCY
(Hz)
3000
125
-P10
250
500
1000
2000
10
(/)
3000
8000
125
-------11=
=
0
-----i--
H
=
-4--
250
500
..
1000
2000
6000
i 4000 : 8000
-10
,
20
0
4000
1
0
(Hz)
6000
-
10
--
20
0
‘
,
.‘,‘
-1-
-?---
-1-
-T--
U,
30
-
m
40
40
-i----
-4----
-j
w
>
-t---
w
-4---
0
-4----
-f.----
-T---
-1-
-t---
---t----
-J
z
ci:
w
I
-I
-4---
w
-4--
w
0
z
a:
----
I
-3--
Fig.
tone
audiogram
60
-1---
-1-
-+--
--
-1--
--------------i--
70
-4---±--
80
-1----
-
-‘---
-
....-.--.
55-year-
Pure
tone
audiogram
of a 57-year-old
showing
features
of noise-induced
hearing
orthopaedic
loss.
THE
AND
Fig.
normal
JOURNAL
._____
-4--
ff
U+
1
of an otologically
--4--
-4-
-f---
w
-_-_-----
Typical
pure
old man.
-
>
90-----4------------t----+--100
-
50
-
2
OF BONE
surgeon
JOINT
SURGERY
NOISE-INDUCED
FREQUENCY
HEARING
LOSS
IN ORTHOPAEDIC
(Hz)
3000
6000
STAFF
115
Noise
emission
levels
do reach
damaging
saws
raised
average
exposure
may
new European
from
levels.
air-powered
Modern
exposure
times : the daily
now exceed
the safe level
Commission
guidelines
safety
at work.
The implications
characteristics
of noise-induced
ered
(McCandless
and
Butler
0
U,
a,
>
w
first it causes
with difficulty
0
z
a:
ground
often
4000
Fig.
Average
pure
noise-induced
tone audiogram
hearing
loss.
3
for
1 1 subjects
with
evidence
of
for all affected
subjects
=
is given
and
considered
for
use
been implicated
loss in dentists.
this
(1982)
nurses
investigating
orthopaedic
with
exposure
of two
theatre
to 15
but
the trend
VOL.
73-B,
suggested
No. I, JANUARY
a potential
1991
hazard.
operating
powered
theatre
for
instruments.
should
lower noise
is therefore
should
be
surgical
In the
be encouraged
emission
levels.
longer
to develop
REFERENCES
in
staff,
years,
demonstrated
a 50% incidence
of minor
audiographic
changes
which
suggested
noise
exposure.
The
mean
hearing
loss of the group
was thought
to be insignificant,
in the
using
here.
It
defenders
younger
hazardous
The author
wishes
to express
his gratitude
for the support
and help of
Dr S. E. Snashall,
Consultant
Audiologist
and
Mr
P. J. Stiles,
Consultant
Orthopaedic
Surgeon,
Royal
Surrey
County
Hospital,
Guildford,
and
to Mr S. Clubb,
Regional
Audiology
Calibration
Technician.
No benefits
in any form
have
been
received
or will be received
from a commercial
party
related
directly
or indirectly
to the subject
of
this article.
senior
faculty
members
at a dental
school
but not in
dental
students.
Zubick,
Tolentino
and
Boffa
(1980)
confirmed
these findings
and also showed
that the left ear
of right-handed
dentists
showed
a greater
loss of hearing;
they related
this to the proximity
of the noise
source.
Kamal
mainly
whilst
term,
manufacturers
instruments
with
identified
to
untreatable.
Noise-induced
hearing
loss is cumulative;
surgeons
will be exposed
to more potentially
in Figure
(1972)
range
(500
is advanced
loss found
in this
study,
average
30 dB impairment
subjects
reported
that
effective
ear
pieces
have
hearing
Burns
is essentially
hearing
of the
progressive,
frequency
the damage
the
Air-powered
and electric
drills and saws are an essential
part of the equipment
for modern
orthopaedic
surgery
and fracture
treatment.
The operators’
intense
concentration while using these tools must reduce
their awareness
Melton
condition
levels
of
fall short
is slowly
the speech
By then
noise
than
recommended
DISCUSSION
Weatherton,
impairment
and for the worst affected
0.02).
The pooled
data
3.
damage
to sensory
susceptibility.
At
defined
by British
Standard
5330:
1976 as constituting
a
handicap
: and even further
short
of the average
50 dB
loss necessary
for disablement
benefit
payments
under
the Social Security
Act of 1975.
teams
of the sound
intensity.
Air-driven
dental
hand
as a cause
of high-frequency
The
The
The
however,
The noise-induced
hearing
loss detected
in this study
showed
a peak loss at 6000 Hz, while the common
pattern
of industrial
‘factory
noise’ damage
is usually
at 4000 Hz.
The mean
loss, corrected
for age and sex, at 6000 Hz for
both ears was 12.3 dB (0 to 40);
ear 15.9 dB (7 to 40, t-test,
p
noise.
severe.
personal
noise
defined
by the
for health
and
inability
to discriminate
consonant
sounds,
in face-to-face
conversation
against
back-
unnoticed
until
Hz) is involved.
and
and
has
are greater
when
the
hearing
loss are consid1983).
Noise-induced
hearing
loss results
from permanent
nerve cells; there is variable
individual
-J
w
drills
practice
Health
and Safety
Commission.
Prevention
of damage
noise
at work.
Draft
proposals
for regulations
Health
and Safety
Commission.
London:
HMSO,
Kamal
SA. Orthopaedic
theatres
Oto 1982; 96 :985-90.
McCandless
GA, Butler G. Noise
WN,
ed. Environmental
and
Brown
and Co, 1983 :707-18.
Shipton
MS.
acoustics
Weatherton
noise
on
Tables
report
MA,
the
: a possible
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to hearing
from
and
guidance.
1987.
hazard
? J Laryng
: effects
of noise on humans.
In : Rom
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medicine.
Boston
: Little,
relating
pure-tone
audiometric
threshold
Ac94.
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Physical
Laboratory
1979.
Melton
hearing
RE, Burns
of dentists.
WW.
The effects
of dental
J Tenn State
Dent Assoc
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drill
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Zubick
HH, Tolentino
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AT, Boffa J. Hearing
loss and the
Am J Pub/ic Health
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high
speed