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Hand-arm Vibration Syndrome study in final stages

By DR. BOB BRUBAKER
and NORMAN GARCIA

At present, researchers are com-
pleting final field work of a six year
study on the health effects of chain
saw vibration on the hands of B.C.
coastal fallers. The researchers
headed by Dr. Bob Brubaker at The
University of British Columbia are
investigating Hand-arm Vibration
Syndrome (HAVS) among coastal fall-
ers exposed to chainsaw vibration for
approximately 3-4 hours daily and up
to 10 months per year.

HAVS is a medical term commonly
used to describe the combination of
symptoms resulting from long term
exposure to hand-arm vibration. This
term is increasingly replacing terms
such as Vibration White Finger Dis-
ease (VWFD) which takes into account
mainly finger whitening attacks and
neglects to imply damage to other
tissues such as nerves and muscle
which also occur.

Initial signs of HAVS can be recur-
ring tingling, then numbing of the
fingers at rest, particularly at night.
Persistent swelling and stiffness of
the fingers and occasional whitening
of a single finger tip on cold exposure
then occurs. Progressive signs include
whitening of one or more fingers even-
tually to the base of the finger,
increased frequency and duration of
whitening attacks lasting from less
than one minute to over fifteen min-
utes in advanced cases, restriction
and elimination of leisure time activi-
ties in cold temperatures, persistent
loss of finger sensation between
attacks, reduction of finger mobility,
dexterity and strength and a perma-
nent blue color to the fingers indicat-
ing obstructive finger blood flow.

The classification system used
worldwide for HAVS was developed
by Drs. Taylor and Pelmear and
includes symptoms of nerve disorders
as well as vascular symptoms. This
system also includes seasonal report-
ing of symptoms as well as interfer-
ence with work and outside activities.

A revision of the Taylor-Pelmear
scale was recently recommended by a
Stockholm Workshop committee in
1986 to omit nerve symptoms (which
can be separately classified) and refer-
ences to seasonal symptoms and dis-
ability which are somewhat subjec-
tive and based on nonmedical factors.

Stockholm Workshop Scale
(Hand-Arm Vibration Syndrome)
Stage Grade Description
0 No attacks
it Mild Occasional attacks
affecting the tips

of one or more fingers
Occasional attacks
affecting the end and
middle parts of one
or more fingers
Frequent attacks
affecting all parts
of most fingers
As in Stage 3, with
skin degeneration in
the finger tips
Some of the main tools in common
use which have been shown to cause
HAVS are the chainsaw, pneumatic
grinders, pneumatic wrenches, and
pedestal grinders. In North America
alone it is estimated there are over one
million workers exhord to stools pee
ing hand-arm vibration and are there-
ae at risk to develop HAVS. Onset of
jptoms can take anywhere from less
a year for rotary gander Obetes
tors, up to 5-7 years for chain saw
operators. :
Phe issue of reversibility of tissue
damage in HAVS is of great impor-
tance in terms of potential anent
disability. It was orginally thought
that most workers with finger whiten-
ing symptoms suffered irreversible
damage with actual progression of
symptoms in some cases after cessa-
tion of vibration exposure. Recent
long term studies have indicated that

2 Moderate

3 Severe

4 Very
Severe

vascular symptoms are reversible in
early stages of the disease with per-
manent damage occurring in some
workers in advanced disease. Evi-
dence for reversibility of neural symp-
toms is poor.

The International Standard (ISO-
DIS 5349) which came into effect in
1986 provides guidelines for the pre-
vention of whitening symptoms in
vibration exposed persons in terms of
years of exposure before onset of
symptoms. The standard does not
take into account occurrence of neural
symptoms which can occur indepen-
dently of vascular symptoms and
which can lead to a more prolonged
disability in terms of reversibility of
symptoms.

The current standard also does not
take into account the interplay be-
tween the operator and the tool, that

e Dr. Bob Brubaker

is the amount of vibration absorbed
into the hand as a result of grip force.
Guidelines in the ISO standard are

based on studies where vibration mea-
surements were carried out on contact
surfaces between the hand and the
tool.

It is interesting to note that the
occurrence and onset of new whiten-
ing symptoms in chainsaw operators
has declined steadily worldwide with
availability of vibration reduced saws
beginning in the early 1970s. For
example, in Finland the occurrence of
vascular symptoms has declined to
levels occurring in the general popula-
tion not exposed to hand-arm vibra-
tion. Similar declines have been
reported in other countries such as
Japan using small, light weight
chainsaws in timber harvesting.

In coastal B.C. however, chainsaws
used in forestry operations are nearly
twice as heavy and are more powerful
because of larger diameter trees.
Occurrence of vascular symptoms in
a 1979-80 study of coastal B.C. fallers
was approximately 50 percent.

The current six year study being
carried out amongst BC. coastal fallers
is to investigate the natural history of
HAVS among this group and to deter-
mine if, as in other countries which
have converted to a new generation of
chainsaws, whether there has been a
significant reduction in incidence and
severity of the disease. The present
study hopes to show over the six year
period whether or not HAVS is wors-
ening, remaining the same, or getting
better.

A small subgroup of the study pop-
ulation went to The University of
British Columbia in the summer of
1988 to have extensive neurological
testing conducted on their hands and
fingers. This testing was conducted
by Dr. Chris vanNetten at UBC and
Dr. Tony Brammer from The National
Research Council. Sophisticated

¢ Faller's hand shows blanching of fingers
in advanced stages of HAVS.

state-of-the-art medical technology
was used to map possible damage of
the nerve receptors in the fingertips
as well as possible damage to nerve
fibers in the fingers and hands.

Final field work for the project
should be completed this Fall when
approximately 70 more fallers, mostly
from the Queen Charlotte Island and
northern Vancouver Island are tested.
In addition, a final phase of chainsaw
vibration monitoring was carried out in
early June in three locations on Van-
couver Island. Using this data, the
study will correlate vibration levels of
the chainsaws with the health effects.

Final study results and recommen-
dations should be available approxi-
mately one year after completion of
the fieldwork.

Researchers examine Faller
and Bucker deaths

A recent paper submitted to the
Scandinavian Journal of Environment
and Health by University of British
Columbia researchers, examines fatal-
ities among British Columbia fallers
and buckers between 1981-1987. The
study, done by D.A. Salisbury, M.D.,
N.H.Sc.; R. Brubaker, Ph.D.; C.
Mertzman, M.D., M.Sc., and G.R.
Loeb, B.Sc., by the Department of
Health Care and Epidemiology (Divi-
sion of Occupational and Environ-
mental Health) at the university, is a
retrospective case series of fatal acci-
dents amongst those particular work-
ers in the British Columbia Forest
Industry.

Eighty-six percent of the workers
deaths analyzed were due to inci-
dences in falling a tree, while just over
9% of fatalities were involved in buck-
ing procedures. Forty-three percent of
the deaths occurred involving stand-
ing dead trees (snags).

A further breakdown of the study
reveals that 10% of deaths occur dur-
ing illegal “domino falling”. In addi-
tion nearly 9% of deaths occur while
falling on the right-of-way where the
“trees must be felled in a direction not
determined by their natural lean or
the position of the work face.”

Examining the work experience of
fatality victims, the study shows that
between 35%-37% of the fatal acci-
dents occur during the first five years
of experience. Unfortunately the
researchers were unable to determine
the total age profile of faller and
buckers. Therefore the statement that
fatalities are higher in the two fore-
mentioned age groups remains un-
proven unless a total breakdown of
age distribution is found.

Examining causes of death, 42
(48.8%) deaths were from head inju-
ries incurred. The information was
obtained from accident reports and
autopsy reports.

Researchers believe that accident inves-
tigations should involve examining “human
factors” before the accident.

More than 22% of the deaths were
due to “multiple unspecified injuries”.
More than 21% of fatalities were either
due to crushed chests or asphyxia.
Six workers died due to blood loss.

Unacceptable falling practices (in-
cluding snag falling, domino fall, and
falling into standing timber) accounted
for 46 or 58% of accidents.

Inanastonishing statistic 32.1% of
the deaths occur to workers injured in
the absence of a partner which is a
contravention of WCB regulations.

Fifty-five percent of the deaths
examined in the study had some ele-
ment of environmental factors (i.e.
an, wind, rain, steepness of terrain,
etc.).

In toxilogical examinations of 76
deaths, there was little evidence of
significantly impairing substances. The
researchers believe the general lack of
toxicological evidence does not sup-
port the perception that drugs and
alcohol are a significant factor in fatal
industrial accidents.

The researchers, note that accident
investigations by the WCB and coro-
ners office, merely focus on sequences
of events during the accident. They
feel that understanding a casualty
should involve an investigation into
factors before the accident took place.

The paper suggests research using
“Human Factors Investigations” done
to analyze factors such as the victims
preceding lifestyle and personality
leading up to the accident. It is sug-
gested that some causal factors may
be identified which may be amenable
to change.

Research revealed that nearly 15%
of major trauma cases involved CPR,
which is used as a technique for mild
heart attacks. According to the
authors: “The appropriateness of this
response to major trauma is question-
able and emphasizes the need of this
technique.” It also raises the question
of what should be taught to first aid
attendants about the management of
major trauma.

Made possible by financial support
from the Canadian Forest Service, the
study was assisted by IWA-CANADA,
the B.C. Coroner's Service, the Coun-
cil of Forest Industries, and the Work-
ers’ Compensation Board.

LUMBERWORKER/JUNE, 1989/9