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Prevalence of carpal tunnel syndrome in a general population

Authors:
  • Malmö University and Lund University

Abstract and Figures

Carpal tunnel syndrome (CTS) is a cause of pain, numbness, and tingling in the hands and is an important cause of work disability. Although high prevalence rates of CTS in certain occupations have been reported, little is known about its prevalence in the general population. To estimate the prevalence of CTS in a general population. General health mail survey sent in February 1997, inquiring about symptoms of pain, numbness, and tingling in any part of the body, followed 2 months later by clinical examination and nerve conduction testing of responders reporting symptoms in the median nerve distribution in the hands, as well as of a sample of those not reporting these symptoms (controls). A region in southern Sweden with a population of 170000. A sex- and age-stratified sample of 3000 subjects (age range, 25-74 years) was randomly selected from the general population register and sent the survey, with a response rate of 83% (n = 2466; 46% men). Of the symptomatic responders, 81% underwent clinical examination. Population prevalence rates, calculated as the number of symptomatic responders diagnosed on examination as having clinically certain CTS and/or electrophysiological median neuropathy divided by the total number of responders. Of the 2466 responders, 354 reported pain, numbness, and/or tingling in the median nerve distribution in the hands (prevalence, 14.4%; 95% confidence interval [CI], 13.0%-15.8%). On clinical examination, 94 symptomatic subjects were diagnosed as having clinically certain CTS (prevalence, 3.8%; 95% CI, 3.1%-4.6%). Nerve conduction testing showed median neuropathy at the carpal tunnel in 120 symptomatic subjects (prevalence, 4.9%; 95% CI, 4.1%-5.8%). Sixty-six symptomatic subjects had clinically and electrophysiologically confirmed CTS (prevalence, 2.7%; 95% CI, 2.1%-3.4%). Of 125 control subjects clinically examined, electrophysiological median neuropathy was found in 23 (18.4%; 95% CI, 12.0%-26.3%). Symptoms of pain, numbness, and tingling in the hands are common in the general population. Based on our data, 1 in 5 symptomatic subjects would be expected to have CTS based on clinical examination and electrophysiologic testing.
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ORIGINAL CONTRIBUTION
Prevalence of Carpal Tunnel Syndrome
in a General Population
Isam Atroshi, MD
Christina Gummesson, MS
Ragnar Johnsson, MD, PhD
Ewald Ornstein, MD
Jonas Ranstam, PhD
Ingmar Rose´n, MD, PhD
C
ARPAL TUNNEL SYNDROME
(CTS), or compression neu-
ropathy of the median nerve
at the wrist, is a cause of pain,
numbness, and tingling in the upper ex-
tremities
1,2
and an increasingly recog-
nized cause of work disability.
3,4
Carpal
tunnel syndrome constitutes a major part
of the occupational upper-extremity dis-
orders and is associated with consider-
able health care and indemnity costs.
4
Although CTS has been described as
the most common peripheral mononeu-
ropathy,
2
little is known about its preva-
lence in the general population. We have
found only 1 prospective population-
based study, performed in the Nether-
lands in 1985, that attempted to deter-
mine the prevalence of CTS.
5
In a survey
of 715 subjects (33% men) aged 25 to
74 years, the prevalence of electrophysi-
ologically confirmed CTS was 5.8% in
women and 0.6% in men.
5
However, the
study’s sample size and response rate
were probably inadequate, reducing its
precision.
Higher prevalence rates for CTS have
been found in certain occupational
groups.
6-8
However, in the absence of
an accurate estimate of the prevalence
in the general population, it is diffi-
cult to interpret prevalence rates re-
lated to specific occupations. There-
fore, we conducted an epidemiologic
study to estimate the prevalence of CTS
in a general population.
METHODS
Study Population and Survey
A sex- and age-stratified sample of 3000
subjects, aged 25 to 74 years, was ran-
domly selected from the population reg-
ister of northeastern Scania in southern
Sweden. This region has a population of
170 000 inhabitants,whose demographic
characteristics are similar to those of the
Swedish general population.
9
The study
was approved by the Ethics Committee
at Lund University’s Medical Faculty.
Author Affiliations: Department of Orthopedics, Ha¨ ssle-
holm-Kristianstad Hospital, Kristianstad, Sweden (Drs
Atroshi and Ornstein); Lund University, Lund, Sweden
(Ms Gummesson); Departments of Orthopedics (Dr
Johnsson) and Clinical Neuroscience, Division of Clini-
cal Neurophysiology (Dr Rose´ n), Lund University Hos-
pital, Lund; and Department of Health and Society,
Malmo¨ University, Malmo¨ , Sweden (Dr Ranstam).
Corresponding Author and Reprints: Isam Atroshi,
MD, Department of Orthopedics, Ha¨ ssleholm-
Kristianstad Hospital, S-291 85 Kristianstad, Sweden
(e-mail: isam.atroshi@mailbox.swipnet.se).
Context Carpal tunnel syndrome (CTS) is a cause of pain, numbness, and tingling in
the hands and is an important cause of work disability. Although high prevalence rates
of CTS in certain occupations have been reported, little is known about its prevalence
in the general population.
Objective To estimate the prevalence of CTS in a general population.
Design General health mail survey sent in February 1997, inquiring about symp-
toms of pain, numbness, and tingling in any part of the body, followed 2 months later
by clinical examination and nerve conduction testing of responders reporting symp-
toms in the median nerve distribution in the hands, as well as of a sample of those not
reporting these symptoms (controls).
Setting A region in southern Sweden with a population of 170 000.
Participants A sex- and age-stratified sample of 3000 subjects (age range, 25-74
years) was randomly selected from the general population register and sent the sur-
vey, with a response rate of 83% (n = 2466; 46% men). Of the symptomatic respond-
ers, 81% underwent clinical examination.
Main Outcome Measures Population prevalence rates, calculated as the number of
symptomatic responders diagnosed on examination as having clinically certain CTS and/or
electrophysiological median neuropathy divided by the total number of responders.
Results Of the 2466 responders, 354 reported pain, numbness, and/or tingling in
the median nerve distribution in the hands (prevalence, 14.4%; 95% confidence in-
terval [CI], 13.0%-15.8%). On clinical examination, 94 symptomatic subjects were
diagnosed as having clinically certain CTS (prevalence, 3.8%; 95% CI, 3.1%-4.6%).
Nerve conduction testing showed median neuropathy at the carpal tunnel in 120 symp-
tomatic subjects (prevalence, 4.9%; 95% CI, 4.1%-5.8%). Sixty-six symptomatic sub-
jects had clinically and electrophysiologically confirmed CTS (prevalence, 2.7%; 95%
CI, 2.1%-3.4%). Of 125 control subjects clinically examined, electrophysiological me-
dian neuropathy was found in 23 (18.4%; 95% CI, 12.0%-26.3%).
Conclusion Symptoms of pain, numbness, and tingling in the hands are common in
the general population. Based on our data, 1 in 5 symptomatic subjects would be ex-
pected to have CTS based on clinical examination and electrophysiologic testing.
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A questionnaire was devised that in-
corporated questions from a validated
general health survey,
10
with questions
about medical history and the pres-
ence of pain, numbness, or tingling in
any part of the body during the preced-
ing 4 weeks as well as their localiza-
tion, duration, frequency, and severity.
Whole body diagrams were provided for
marking pain, numbness, and tingling.
Demographic data included sex, age,
handedness, height, weight, social sta-
tus, education, amount of exercise,
smoking habits, employment, and work
activities. The study was presented in the
local media 1 week before the mailing
of the questionnaires. To reduce selec-
tion bias, the study was described as a
general health survey. The question-
naires were mailed to the 3000 sub-
jects in February 1997. Two consecu-
tive reminders were mailed to those who
did not respond within 3 weeks. All re-
turned questionnaires were reviewed
twice by 2 investigators to identify sub-
jects reporting symptoms in the me-
dian nerve distribution in the hands. Re-
sponders who reported pain, numbness,
and/or tingling in 2 or more of the first
4 fingers at least twice weekly during the
preceding 4 weeks were identified. They
were then contacted by telephone or, if
necessary, by mail, and asked to come
to the hospital for a clinical examina-
tion and nerve conduction testing.
Controls were randomly selected
from the responders who reported no
hand symptoms, diabetes, rheumatic
disease, thyroid disorder, previous wrist
fracture, or carpal tunnel surgery. The
controls were also asked to come to the
hospital for examination.
Subjects in a random sample of 10%
of the nonresponders were contacted
by telephone and questioned about the
presence of hand symptoms.
Clinical Examination
The clinical examinations were begun 2
months after the initial mailing of the
questionnaires and conducted during a
4-week period. All subjects were exam-
ined by the same hand surgeon (I.A.),
who is experienced in the assessment of
CTS. Examination of both hands in-
cluded median nerve provocative tests
(Tinel nerve percussion and Phalen ma-
neuver), and evaluation of sensibility and
thenar muscle strength.
1,2
All hands pre-
viously operated on for CTS were ex-
cluded. Based on the history and the find-
ings at the clinical examination, the
examining physician diagnosed each
symptomatic subject as having either
clinically certain or clinically uncertain
CTS. The diagnosis of clinically certain
CTS required the presence of recurring
nocturnal and/or activity-related numb-
ness or tingling involving the palmar as-
pects of at least 2 of the first 4 fingers. It
usually included positive nerve percus-
sion and/or wrist flexion test results. The
presence of median nerve sensory and/or
motor deficit was supportive of the di-
agnosis, but was not considered nec-
essary. The diagnosis of clinically un-
certain CTS was considered for the
symptomatic subjects reporting poorly
defined median nerve paresthesias, whole
hand or arm paresthesias, or chronic pain
as the main clinical feature.
Nerve Conduction Testing
After the clinical examination the sub-
jects underwent nerve conduction test-
ing using an electromyography device
(Viking IV; Nicolet, Madison, Wis). The
nerve conduction testing was per-
formed by 3 experienced electromyog-
raphy technicians who were blinded to
the results of the preceding examina-
tion. Skin temperature was measured
prior to testing, and hands with a
temperature of less than 30°C were
warmed. Nerve conduction testing was
performed using the technique de-
scribed by Kimura
11
and included mea-
surements of median nerve distal sen-
sory latency (third finger–wrist) and
wrist-palm sensory conduction veloc-
ity, as well as ulnar nerve distal sen-
sory latency (fifth finger–wrist).
11,12
The results of the nerve conduction
testing were examined to identify sub-
jects with electrophysiological me-
dian neuropathy at the carpal tunnel.
The electrophysiological criterion used
for the diagnosis of median neuropa-
thy was median-ulnar sensory latency
difference,
13
with 0.8 milliseconds or
longer considered abnormal. This cut-
off was used in accordance with the pre-
viously reported normal values for me-
dian-ulnar wrist-digit latency difference
as measured with the technique de-
scribed by Kimura.
11
Data Analysis
We calculated the prevalence of pain,
numbness, and/or tingling in the me-
dian nerve distribution, clinically cer-
tain CTS, electrophysiological median
neuropathy, and clinically and electro-
physiologically confirmed CTS. The
prevalence rates were calculated as the
number of subjects in each of the 4 cat-
egories divided by the total number of
survey responders. Ninety-five per-
cent confidence intervals (CIs) were cal-
culated based on the Poisson distribu-
tion.
14
Sex- and age-specific prevalence
rates were also calculated. Sex-
specific overall prevalence rates were
age standardized using the general
Swedish population in December 1997
9
as an external standard. Group com-
parisons were performed using 2-tailed
x
2
tests for categorical data and t tests
for continuous variables, with signifi-
cance set at .05.
RESULTS
Survey
Of the 3000 subjects, 15 had recently
moved from the study region, 5 were
reported recently deceased, 8 were se-
verely ill or cognitively impaired, and
12 had recently relocated to unknown
addresses. Of the remaining 2960 sub-
jects, 2466 (83%) returned completed
questionnaires (F
IGURE).
Symptomatic Subjects
Symptoms of recurring pain, numb-
ness, and/or tingling in the median
nerve distribution were reported by 354
responders (34% men; mean [SD] age,
51 [13] years). There were 2112 non-
symptomatic responders (48% men;
mean [SD] age, 50 [15] years). A sig-
nificantly higher proportion of women
were symptomatic (P,.001).
Of the symptomatic responders, 287
subjects (81%) came to the hospital for
the clinical examination. Twenty-five
CARPAL TUNNEL SYNDROME
154 JAMA, July 14, 1999—Vol 281, No. 2 ©1999 American Medical Association. All rights reserved.
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subjects were excluded for the follow-
ing reasons: previous CTS surgery in the
symptomatic hand (n = 13), unwilling-
ness to undergo nerve conduction test-
ing (n = 2), and either resolution of the
median nerve symptoms or symptoms
not consistent with the inclusion cri-
teria (n = 10).
Clinical examination and nerve con-
duction testing were performed on 262
symptomatic subjects (35% men; mean
[SD] age, 52 [13] years). The results of
the clinical and electrophysiological ex-
aminations are shown in the Figure.
There was a fair-to-moderate agree-
ment between the clinical diagnosis
(clinically certain CTS vs clinically un-
certain or no CTS) and the electrophysi-
ological diagnosis (median neuropathy
or no median neuropathy) (k = 0.36;
P,.001), and good agreement be-
tween the clinical diagnosis alone and
the clinical and electrophysiological di-
agnosis (k = 0.75; P,.001).
14
Prevalence
The population prevalence of pain,
numbness, and/or tingling in the me-
dian nerve distribution was 14.4% (95%
CI, 13.0%-15.8%). The sex- and age-
specific prevalence rates are shown in
T
ABLE 1. The prevalence of clinically
certain CTS was 3.8% (95% CI, 3.1%-
4.6%). The prevalence of median nerve
symptoms and electrophysiological me-
dian neuropathy was 4.9% (95% CI,
4.1%-5.8%). The prevalence of clini-
cally and electrophysiologically con-
firmed CTS was 2.7% (95% CI, 2.1%-
3.4%). The sex- and age-specific
prevalence rates are shown in T
ABLE 2.
Medical and Occupational Data
Diabetes was reported in 3.0% of the
subjects with clinically and electro-
physiologically confirmed CTS and
3.2% of the remaining responders. Also
reported were thyroid disorder in 3.0%
and 3.0%, rheumatoid arthritis in 4.5%
and 1.9%, and overweight or obesity
(defined as body mass index of at least
25 kg/m
2
) in 70% and 47%, respec-
tively. The higher proportion of over-
weight or obese subjects in the CTS
population was significant (P,.001).
Clinically and electrophysiologically
confirmed CTS was present in 25 of 710
active blue-collar workers (prevalence,
3.5%), and in 12 of 712 active white-
collar workers (prevalence, 1.7%) (95%
CI for the difference, 0.2%-3.6%; P = .03).
The higher prevalence among active
blue-collar workers was significant even
after adjusting for sex, age, and body
mass index. The prevalence of con-
firmed CTS among working subjects
who reported more than 1 h/d use of ex-
cessive force with the hand during work
and those reporting less frequent or no
such use was 5.4% and 1.8%, respec-
tively (95% CI for the difference, 1.4%-
6.8%; P,.001). In a similar analysis of
other work-related activities (ie, use .1
Figure. Study Profile
Subjects Surveyed
(N
=
3000)
Deceased, Relocated, Severely Ill, Cognitively Impaired
(n
=
40)
Responders
(N
=
2466)
Symptomatic
(Pain, Numbness, Tingling in Median Nerve Distribution)
(n
=
354)
Clinical Examination
(n
=
287)
Median Neuropathy
(n
=
66)
No Neuropathy
(n
=
28)
Nerve Conduction Testing
Did Not Attend Clinical Examination
(n
=
67)
Clinically Certain
Carpal Tunnel Syndrome
(n
=
94)
No Neuropathy
(n
=
114)
Nerve Conduction Testing
Clinically Uncertain
Carpal Tunnel Syndrome
(n
=
168)
No Neuropathy
(n
=
102)
Excluded (n
=
25)
Previous Carpal Tunnel Surgery (n
=
13)
No Median Nerve Symptoms (n
=
10)
Declined Nerve Conduction Testing (n
=
2)
Excluded (n
=
9)
Neurologic Disease (n
=
1)
Median Nerve Symptoms (n
=
7)
Declined Nerve Conduction Testing (n
=
1)
Nerve Conduction Testing
Clinically No
Carpal Tunnel Syndrome
(n
=
125)
Median Neuropathy
(n
=
54)
Median Neuropathy
(n
=
23)
Clinical Examination
(Randomly Selected)
(n
=
134)
Nonresponders
(n
=
494)
Nonsymptomatic
(n
=
2112)
CARPAL TUNNEL SYNDROME
©1999 American Medical Association. All rights reserved. JAMA, July 14, 1999—Vol 281, No. 2 155
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h/d vs use #1 h/d), CTS prevalence in
the 2 groups was, for working with ex-
cessively flexed or extended wrist, 3.8%
and 1.7% (95% CI for the difference,
0.4%-4.1%; P = .01); for repetitive hand
or wrist motion, 2.4% and 2.7% (95% CI
for the difference, 2.0%-1.5%; P = .69);
and for use of hand-held vibratory tools,
5.5% and 2.4% (95% CI for the differ-
ence, 0.0%-9.1%; P = .05).
Controls
Of the nonsymptomatic responders
asked to come to the hospital, 134 sub-
jects received a clinical examination.
Nine subjects were excluded for the fol-
lowing reasons: neurological disease
(n = 1), unwillingness to undergo nerve
conduction testing (n = 1), and pres-
ence of median nerve numbness or tin-
gling (n = 7).
Clinical examination and nerve con-
duction testing were performed on 125
control subjects (45% men; mean [SD]
age, 51 [14] years). In 3 subjects, nerve
conduction testing was performed on
only 1 hand owing to a previous nerve
laceration involving the right wrist
(n = 1) and unwillingness to proceed
with examination of the left hand (n = 2).
Electrophysiological median neu-
ropathy was found in 23 control sub-
jects (18.4%; 95% CI, 12.0%-26.3%)
(T
ABLE 3). Six of 41 active blue-collar
workers and 5 of 45 active white-
collar workers had median neuropa-
thy. Analysis of the work-related ac-
tivities in the controls did not show
significant differences regarding the
prevalence of median neuropathy.
Nonresponders
A total of 494 eligible subjects (52%
men; mean [SD] age, 47 [14] years) did
not respond to the questionnaire. The
nonresponders differed significantly
from the responders with respect to sex
(P = .02) and age (P,.001). Tele-
phone contact was attempted with 49
randomly selected nonresponders.
Twenty-two subjects could not be
reached, 1 was reported to have re-
cently died, and 2 declined to answer
any questions. Responses could thus be
obtained from 24 subjects (11 men).
Numbness and/or tingling in the hands
were reported in 6 subjects.
Sixty-seven symptomatic subjects
(37% men; mean [SD] age, 50 [12]
years) did not come to the clinical ex-
amination.
COMMENT
The findings of this epidemiologic study
of CTS, the largest to date, show this
compression neuropathy to be com-
mon in the general population. The
prevalence of upper-extremity pain and
paresthesias in the general population
has not been addressed in the litera-
ture. The high prevalence of these symp-
toms in the general population should
be borne in mind when assessing the pos-
sible relationship of upper-extremity
complaints to specific occupations.
Table 1. Prevalence of Pain, Numbness, and/or Tingling in the Median Nerve Distribution in Hands (N = 2466)
*
Age, y
Men
Women
Responders, No. Symptomatic, No.
Prevalence, %
(95% CI) Responders, No. Symptomatic, No.
Prevalence, %
(95% CI)
25-34 219 11 5.0 (2.5-8.8) 244 30 12.3 (8.4-17.1)
35-44 213 17 8.0 (4.7-12.5) 280 55 19.6 (15.1-24.8)
45-54 209 32 15.3 (10.7-20.9) 280 50 17.9 (13.5-22.8)
55-64 259 41 15.8 (11.6-20.8) 252 59 23.4 (18.3-29.1)
65-74 234 20 8.5 (5.3-12.9) 276 39 14.1 (10.2-18.8)
All† 1134 121 10.4 (8.6-12.2) 1332 233 17.3 (15.3-19.4)
*
CI indicates confidence interval.
†The sex-specific overall prevalence rates are age standardized to the Swedish general population.
Table 2. Sex- and Age-Specific Prevalence Rates of Carpal Tunnel Syndrome
*
Age, y
Men
Women
Clinically
Certain CTS
Electrophysiological
Median Neuropathy
at the Carpal Tunnel
Clinically and
Electrophysiologically
Confirmed Diagnosis
of CTS
Clinically
Certain CTS
Electrophysiological
Median Neuropathy
at the Carpal Tunnel
Clinically and
Electrophysiologically
Confirmed Diagnosis
of CTS
No.
Prevalence, %
(95% CI) No.
Prevalence, %
(95% CI) No.
Prevalence, %
(95% CI) No.
Prevalence, %
(95% CI) No.
Prevalence, %
(95% CI) No.
Prevalence, %
(95% CI)
25-34 3 1.4 (0.3-3.9) 4 1.8 (0.5-4.6) 2 0.9 (0.1-3.3) 7 2.9 (1.2-5.8) 5 2.0 (0.7-4.7) 4 1.6 (0.5-4.1)
35-44 3 1.4 (0.3-4.1) 6 2.8 (1.0-6.0) 2 0.9 (0.1-3.3) 16 5.7 (3.3-9.1) 11 3.9 (2.0-6.9) 8 2.9 (1.2-5.5)
45-54 11 5.3 (2.7-9.2) 17 8.1 (4.8-12.7) 9 4.3 (2.0-8.0) 11 3.9 (2.0-6.9) 18 6.4 (3.8-10.0) 8 2.9 (1.2-5.5)
55-64 10 3.9 (1.9-7.0) 14 5.4 (3.0-8.9) 8 3.1 (1.3-6.0) 14 5.6 (3.0-9.1) 20 7.9 (4.9-12.0) 8 3.2 (1.4-6.2)
65-74 4 1.7 (0.5-4.3) 7 3.0 (1.2-6.1) 3 1.3 (0.3-3.7) 15 5.4 (3.1-8.8) 18 6.5 (3.9-10.1) 14 5.1 (2.8-8.4)
All† 31 2.8 (1.8-3.8) 48 4.3 (3.1-5.5) 24 2.1 (1.3-3.0) 63 4.6 (3.5-5.7) 72 5.2 (4.0-6.3) 42 3.0 (2.1-3.9)
*
CTS indicates carpal tunnel syndrome; CI, confidence interval.
†The sex-specific overall prevalence rates are age standardized to the Swedish general population.
CARPAL TUNNEL SYNDROME
156 JAMA, July 14, 1999—Vol 281, No. 2 ©1999 American Medical Association. All rights reserved.
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Despite the high incidence of sur-
gery for CTS, no standard criteria for
clinical diagnosis have been estab-
lished.
1
There is also no consensus on
whether CTS is a clinical or electro-
physiological diagnosis. Normal elec-
trophysiological findings do not rule out
CTS.
15
In fact, most studies assessing the
sensitivity of nerve conduction testing
in diagnosing CTS have used the clini-
cal diagnosis as the criterion stan-
dard.
15
On the other hand, physical
examination for CTS also has been re-
ported to have limited sensitivity and
specificity.
16
Consequently, we calcu-
lated 2 separate prevalence rates: 1 in
which the diagnosis of CTS was made
on the basis of characteristic symp-
toms and signs and 1 requiring median
nerve symptoms combined with elec-
trophysiological median neuropathy. We
also calculated a conservative preva-
lence estimate based on clinically and
electrophysiologically confirmed diag-
noses. Although this figure may be an
underestimate because it excludes elec-
trophysiologically normal subjects with
clear clinical features of CTS, this preva-
lence estimate is important for epide-
miologic studies because it probably rep-
resents the highest level of classification
accuracy.
17
That only 1 clinician per-
formed the clinical examinations may be
a source of potential bias.
We found electrophysiological me-
dian neuropathy not only in 70% of the
subjects diagnosed as having clini-
cally certain CTS and in 46% of those
with paresthesias in the median nerve
distribution in the hands, but also in
18% of the nonsymptomatic control
subjects. Abnormal nerve conduction
testing results were more common
among older control subjects. The rea-
son for this high rate of asymptomatic
median neuropathy is unclear. Al-
though abnormal nerve conduction
testing results have been reported in
nonsymptomatic subjects, previous
electrodiagnostic studies generally have
not used controls randomly selected
from the general population.
15
Asymp-
tomatic median neuropathy has previ-
ously been found in 13% of 724 indus-
trial and/or clerical workers,
18
and in
16% of 1021 industrial job appli-
cants.
19
These 2 studies used median-
ulnar sensory latency difference mea-
sured at a distance of 14 cm (digit-
wrist) and 8 cm (palm-wrist),
respectively, using the 0.5-millisec-
ond cutoff commonly used for these
measurement techniques. A higher cut-
off for the latency difference has been
derived from the technique described
by Kimura, in which the median and
ulnar nerves are stimulated at a fixed
point (3 cm proximal to the wrist’s dis-
tal crease) and the recording made at
the interphalangeal joints of the third
and fifth digits, respectively.
11
A re-
cent study reporting normative me-
dian and ulnar nerve conduction val-
ues in 324 nonsymptomatic active
workers with a mean age of 36 years
suggested the use of a 0.8-millisecond
cutoff for the 14-cm sensory latency dif-
ference to reduce the false-positive
rate.
20
Our results using the alterna-
tive measurement technique also show
that the rate of asymptomatic median
neuropathy in a general population
appears to be higher than previously
reported in nonrandom, and often
smaller, control groups.
We found a strong association be-
tween overweight or obesity and the
presence of CTS. The other medical
conditions analyzed did not show sig-
nificant associations, although rheu-
matoid arthritis was more commonly
reported than the other conditions
among CTS subjects. Our findings of
higher CTS prevalence among blue-
collar than white-collar workers, and
among workers who reported using ex-
cessive force with the hand or work-
ing with excessive wrist flexion or ex-
tension, might provide additional
support to the role of work-related fac-
tors in CTS.
In our study, the prevalence of CTS
recorded in men (male-female ratio,
1:1.4) was higher than previously re-
ported.
5,21
This difference in the re-
ported prevalence rates might be due to
differences in the size and/or design of
earlier studies, or to a real increase in the
prevalence in men. Among older per-
sons, however, the prevalence in women
was almost 4 times that in men, with
older women showing the highest age-
specific prevalence for confirmed CTS.
Since we had a response rate exceed-
ing 80% for both the survey and the
clinical examination, we believe selec-
tion bias is a minor problem. Further-
more, the nonresponder analysis re-
vealed almost similar proportions of
symptomatic subjects among the non-
responders as among the responders.
In addition, the rate of false-positive
and false-negative questionnaire re-
sponses regarding hand symptoms
was shown to be low.
When calculating prevalence rates,
we assumed that symptomatic sub-
jects who did not come to the exami-
nation (19% of all symptomatic sub-
jects) did not have CTS. Consequently,
based on clinical and/or electrophysi-
ological criteria, the prevalence rates es-
timated in our study ought to be close
to, or somewhat lower than, the true
prevalence.
Estimation of CTSprevalence rates in
the general population may contribute
to earlydiagnosis and effective treatment
of symptomatic subjects and provideuse-
ful data for the interpretation of results
of studies that estimate CTS prevalence
in specific occupational groups.
Funding/Support: This study was supported by grants
from the Kristianstad County Council, the Medical
Faculty of Lund University, and by grants 17x-09509
and 14x-0084 from the Swedish Medical Research
Council.
Acknowledgment: We would like to thank electro-
myography technicians Marie Lindvall, Pernilla Lin-
de´n, and Inger Nordlund for their skillful neurogra-
phy work and Roger Nihle´ n, RN, for his useful technical
assistance.
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35-44 2 (1) 7.8
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55-64 4 (1) 23.5
65-74 10 (5) 31.2
All 23 (11) 18.4
CARPAL TUNNEL SYNDROME
©1999 American Medical Association. All rights reserved. JAMA, July 14, 1999—Vol 281, No. 2 157
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CARPAL TUNNEL SYNDROME
158 JAMA, July 14, 1999—Vol 281, No. 2 ©1999 American Medical Association. All rights reserved.
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... Carpal tunnel syndrome (CTS) is a disease that not only causes numbness in the hand as the median nerve is compressed at the wrist, but also causes weakness in the hand muscles in severe cases. It is the most common focal compressive neuropathy, with a prevalence of approximately 3% in the general population (5). Therefore, its diagnosis and appropriate treatment are very important for clinicians. ...
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Background: In case of focal neuropathy, the muscle fibers innervated by the corresponding nerves are replaced with fat or fibrous tissue due to denervation, which results in increased echo intensity (EI) on ultrasonography. EI analysis can be conducted quantitatively using gray scale analysis. Mean value of pixel brightness of muscle image defined as EI. However, the accuracy achieved by using this parameteralone to differentiate between normal and abnormal muscles is limited. Recently, attempts have been made to increase the accuracy using artificial intelligence (AI) in the analysis of muscle ultrasound images. CTS is the most common disease among focal neuropathy. In this study, we aimed to verify the utility of AI assisted quantitative analysis of muscle ultrasound in CTS. Methods: This is retrospective study that used data from adult who underwent ultrasonographic examination of hand muscles. The patient with CTS confirmed by electromyography and subjects without CTS were included. Ultrasound images of the unaffected hands of patients or subjects without CTS were used as controls. Ultrasonography was performed by one physician in same sonographic settings. Both conventional quantitative grayscale analysis and machine learning (ML) analysis were performed for comparison. Results: A total of 47 hands with CTS and 27 control hands were analyzed. On conventional quantitative analysis, mean EI ratio (i.e. mean thenar EI/mean hypothenar EI ratio) were significantly higher in the patient group than in the control group, and the AUC was 0.76 in ROC analysis. In the analysis using machine learning, the AUC was the highest for the linear support vector classifier (AUC=0.86). When recursive feature elimination was applied to the classifier, the AUC value improved to 0.89. Conclusion: This study showed a significant increase in diagnostic accuracy when AI was used for quantitative analysis of muscle ultrasonography. If an analysis protocol using machine learning can be established and mounted on an ultrasound machine, a noninvasive and non-time-consuming muscle ultrasound examination can be conducted as an ancillary tool for diagnosis.
... Carpal tunnel syndrome (CTS) is an entrapment neuropathy caused by compression of the median nerve at the wrist and is the most common of all entrapment neuropathies with a prevalence of 4.9% in the general population. 1 It has been suggested that pathological processes such as flexor tenosynovitis, vascular sclerosis, fibrous hypertrophy and synovial edema may cause the development of idiopathic CTS. 2,3 Neuropathic pain is defined as the pain that occurs as a result of a disease or lesion affecting the somatosensory system. ...
... Although there is some indication that type 1 (reflex sympathetic dystrophy) is more frequent among diabetics, this link is not well established. As in previous cases, there is a complaint of discomfort, as well as warning symptoms of skin changes, hyperaesthesia, and vasomotor instability (Atroshi, 1999). ...
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Type 1 and Type 2 diabetes are becoming more common in the world. Many people suffer daily from what they have been told is carpal tunnel syndrome. As a result of their pain and disability.While musculoskeletal symptoms of diabetes are frequent and, while not life-threatening, are a major source of morbidity, pain, and disability, vascular consequences of diabetes are widely known and primarily responsible for mortality and morbidity from the illness. Peripheral joints and the axial bone are among the joints that are impacted by diabetes. The peripheral neuropathy condition Charcot neuroarthropathy is a significant contributor to deformity and amputation. Known fibrosing diseases of the hands and shoulder include carpal tunnel syndrome, adhesive capsulitis, tenosynovitis, and limited joint mobility. Gout and Osteoporosis are more common among diabetics. Early detection and strong communication between experts in diabetes and rheumatology are essential for the management of both disorders.
... The carpal tunnel is a fibro-osseous tunnel in the wrist through which the flexor tendons and median nerve pass into the hand [1]. Carpal tunnel syndrome (CTS) is a clinical disorder caused by increased pressure on the median nerve within the carpal tunnel [2] and is the most common peripheral nerve entrapment neuropathy [3,4] Several treatment options are available for CTS, and the preferred treatment depends on disease severity, symptom duration, and patient preferences [5]. If nonoperative methods, including wrist splinting, physical therapy, and corticosteroid injection, are ineffective, a surgical release should be considered. ...
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Objective: To compare transverse and longitudinal safe zones using ultrasonography between healthy individuals and patients with carpal tunnel syndrome (CTS). Methods: This was a prospective observational case-control study. Forty wrists from 20 healthy individuals and 40 wrists from 24 patients with CTS were examined. Patients with CTS were classified into three groups (mild, moderate, and severe CTS) based on electrodiagnostic findings. Using ultrasonography, we measured the distance between the median nerve and ulnar vessels to identify the transverse safe zone, and between the distal flexor retinaculum and superficial palmar artery arch to identify the longitudinal safe zone. Results: The transverse and longitudinal safe zones were significantly different between participants with CTS and those without CTS. The transverse safe zone significantly differed between the mild and severe CTS groups, while the longitudinal safe zone was not significantly different between the groups. The cross-sectional area of the median nerve negatively correlated with the transverse and longitudinal safe zones. Conclusion: Transverse and longitudinal safe zones were narrower in patients with CTS than in the healthy group. A significant difference was observed between patients with mild CTS and those with severe CTS. Furthermore, the cross-sectional area of the median nerve was directly proportional to the degree of narrowing of the transverse and longitudinal safe zones.
... As the severity increases, this often starts at night and continues throughout the day. Dentists are more likely to experience hand and finger discomfort symptoms than the general population since they ostensibly put in more hours at work [5] . Forceful hand movements during scaling and extractions, using vibrating ultrasonic equipment, and frequently working with the wrist in flexion or extension are all potential causes of CTS in the dentistry profession. ...
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Dentists in their practice are exposed to work-related vibrations on a daily basis. Carpel tunnel syndrome occurs due to overuse of the hand while using vibratory equipment such as sizing, turbines, and handles with slow speeds, gripping and working with tools or other small objects such as endodontic files.
... "p" is the probability of occurrence of the examined event (p=0.05); [3] "q" is the probability of the examined event not occurring (q=0.95); "d" is the deviation from the frequency of occurrence of the event (d=0.03). ...
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Objectives: This study aims to investigate the use of and addiction to smartphones in individuals with and without carpal tunnel syndrome (CTS). Patients and methods: The cross-sectional study included a total of 404 participants (286 females, 118 males; mean age: 39.7±11.6 years; range, 16 to 75 years) who applied to the Neurology Department of the Fırat University Faculty of Medicine, between April 2019 and October 2019. The participants were divided into two groups: 202 patients diagnosed with CTS were included in the case group, and 202 patients and their relatives who did not have hand and wrist complaints were included in the control group. The diagnosis of CTS was made by evaluating the history, physical examination, and electromyography findings. Data were collected with participant information forms and the Smartphone Addiction Scale. Results: It was found that the risk of CTS increased 1.022 times with a one-unit increase in the SAS score and 1.292 times with a 1-h increase in daily smartphone use. Conclusion: Smartphone addiction can be considered as a potential risk factor for CTS; however, the effect of smartphone addiction on CTS severity was not examined in this study. The relationship between disease severity, smartphone use, and smartphone addiction in CTS patients requires further investigation to provide clarification on this issue.
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Objectives: The ultrasound diagnosis of mild carpal tunnel syndrome (CTS) is challenging. Radiomics can identify image information that the human eye cannot recognize. The purpose of our study was to explore the value of ultrasound image-based radiomics in the diagnosis of mild CTS. Methods: This retrospective study included 126 wrists in the CTS group and 88 wrists in the control group. The radiomics features were extracted from the cross-sectional ultrasound images at the entrance of median nerve carpal tunnel, and the modeling was based on robust features. Two radiologists with different experiences diagnosed CTS according to two guidelines. The area under receiver (AUC) operating characteristic curve, sensitivity, specificity, and accuracy were used to evaluate the diagnostic efficacy of the two radiologists and the radiomics model. Results: According to guideline one, the AUC values of the two radiologists for CTS were 0.72 and 0.67, respectively; according to guideline two, the AUC were 0.73 and 0.68, respectively. The radiomics model achieved the best accuracy when 16 important robust features were selected. The AUC values of training set and test set were 0.92 and 0.90, respectively. Conclusions: The radiomics label based on ultrasound images had excellent diagnostic efficacy for mild CTS. It is expected to help radiologists to identify early CTS patients as soon as possible, especially for inexperienced doctors.
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The diagnosis of degenerative cervical myelopathy can generally be made with a thorough history, physical examination, and spinal imaging. Electrodiagnostic studies, consisting of nerve conduction studies and electromyography, are a useful adjunct when the clinical picture is inconsistent or there is concern for overlapping pathology. Electrodiagnostic studies may be particularly helpful in identifying cases of myeloradiculopathy, when there is combined nerve root and spinal cord injury, both with regards to prognosis and guiding surgical treatment. Electrodiagnostic studies are a useful adjunct for the spine surgeon and should be used when there are features atypical for degenerative cervical myelopathy or when there is suspicion for a concomitant disease process.
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Objective: Carpal tunnel syndrome (CTS) is the most common peripheral entrapment neuropathy, and endoscopic carpal tunnel release (ECTR) is one of the minimally invasive procedures for the treatment of CTS. Based on the shortcomings of ECTR, we designed the "Modified Soft Tissue Release Kit" to assist the endoscopic operation. This study aimed to evaluate the effectiveness and safety of endoscopic treatment of CTS using this kit. Methods: This retrospective review included 57 patients (86 wrists) who underwent ECTR using the "Modified Soft Tissue Release Kit" at our department between January 2017 and August 2019. Three scale scores (i.e., Quick-Disabilities of the Arm, Shoulder, and Hand [QDASH]; Boston Carpal Tunnel Syndrome Questionnaire [BCTSQ]: symptom severity [BCTSQ-SS] and functional status [BCTSQ-FS]) were recorded to assess hand function and symptoms preoperatively, 1 month postoperatively, 3 months postoperatively, and at the last follow-up. We also asked patients to answer a satisfaction question during follow-up. Pre- and post-operation scores were compared using paired Wilcoxon signed-rank test. Spearman's rank-order correlation was used to evaluate the relationship between scale scores and patient satisfaction. Results: A total of 55 patients (83 wrists) were followed up, with an average follow-up of 27.2 ± 9.3 months. The median preoperative QDASH score was 45.5; the scores at 1 month postoperatively, 3 months postoperatively, and the last follow-up were 4.5, 0, and 0, respectively, with a significant decrease noted compared with the preoperative scores (P < 0.001). The median preoperative BCTSQ-SS and BCTSQ-FS scores were 3.3 and 2.8, respectively; the scores at 1 month postoperatively, 3 months postoperatively, and the last follow-up were 1.2, 1.0, and 1.0, and 1.1, 1.0, and 1.0, respectively, all of which decreased significantly compared with the preoperative scores (P < 0.001). The incidence of nerve injury was 0. The incidence of pillar pain was 0 at the last follow-up. One patient showed no improvement in hand symptoms and function postoperatively, and two patients showed long-term recurrence despite postoperative symptom remission. Approximately 94.5% (52/55) of the patients were satisfied or very satisfied with the outcome. Conclusions: ECTR with the "Modified Soft Tissue Release Kit" can significantly relieve symptoms and improve function in patients with CTS, with significant short- and mid-term efficacy and high safety.
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A 36-item short-form (SF-36) was constructed to survey health status in the Medical Outcomes Study. The SF-36 was designed for use in clinical practice and research, health policy evaluations, and general population surveys. The SF-36 includes one multi-item scale that assesses eight health concepts: 1) limitations in physical activities because of health problems; 2) limitations in social activities because of physical or emotional problems; 3) limitations in usual role activities because of physical health problems; 4) bodily pain; 5) general mental health (psychological distress and well-being); 6) limitations in usual role activities because of emotional problems; 7) vitality (energy and fatigue); and 8) general health perceptions. The survey was constructed for self-administration by persons 14 years of age and older, and for administration by a trained interviewer in person or by telephone. The history of the development of the SF-36, the origin of specific items, and the logic underlying their selection are summarized. The content and features of the SF-36 are compared with the 20-item Medical Outcomes Study short-form.
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Dr. Kimura has built upon his extensive experience teaching electromyography (EMG) around the world and has transferred his knowledge to this resource, which is intended for clinicians who perform electrodiagnostic procedures as an extension of their clinical examination. It covers noninvasive electrodiagnostic methods, particularly electromyography (EMG). This resource provides a comprehensive review of most peripheral nerve and muscle diseases, including specific techniques and locations for performing each test.
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Carpal tunnel syndrome (CTS) is the most commonly reported nerve entrapment syndrome. The prevalence of CTS among 652 active workers in jobs with specific hand force and repetitiveness characteristics was estimated. The prevalence of CTS ranged from 0.6% among workers in low force–low repetitive jobs to 5.6% among workers in high force–high repetitive jobs. When controlling for potential confounders, the odds ratio for the high force-high repetitive jobs was more than 15 (p < .001) compared to the low force–low repetitive jobs. High repetitiveness appears to be a greater risk factor than high force (odds ratio of 5.5, p < .05 versus 2.9 and not statistically significant).
Article
The objective of this study was to describe patterns and predictors of work absence in the prospective, community-based Maine Carpal Tunnel Study. Three hundred fifteen patients with carpal tunnel syndrome (CTS) were recruited from physicians' offices throughout Maine. The patients completed questionnaires at entry and after 6, 18, and 30 months. The questionnaires included scales measuring symptom severity, functional status, general and mental health status, exposure to physical stressors, work status, and other indicators. The analyses examined univariate and multivariate correlates of work absence. The mean age was 43, 72% of subjects were female, 71% underwent carpal tunnel release, and 45% were receiving Workers' Compensation. Fifty-two percent worked in managerial or technical occupations, 15% in service occupations, and 13% in heavy labor or machine operation. Forty-five percent of patients changed jobs or were absent from work (aside from postoperative recovery) during the 30-month follow-up. In multivariate logistic regression models, correlates of work absence at 18 months included worse functional status of the hand at study entry and at 6-month follow-up, involvement of an attorney at the time of enrollment (P < 0.002 for each), and work absence at 6 months (P = 0.03). Worse upper extremity functional status and having a contested Workers' Compensation claim are critical predictors of work absence and should be principal targets of interventions to reduce work disability in CTS. Am. J. Ind. Med. 33:543–550, 1998. © 1998 Wiley-Liss, Inc.
Article
The objective was to determine whether symptomatic workers with an abnormal sensory nerve conduction study consistent with carpal tunnel syndrome differed, in terms of electrophysiologic measures, psychosocial, demographic, anthropometric, or ergonomic variables, from workers with an asymptomatic median mononeuropathy. This was a cross-sectional study of active workers at six different work sites. Cases were defined as workers with electrodiagnostic findings of a median mononeuropathy in either hand, based on a 0.5-msec prolongation of the median sensory evoked peak latency compared to the ulnar latency. This group was stratified on the basis of symptoms of numbness, tingling, burning or pain in the hand. The two groups were compared in terms of demographic, anthropomorphic, psychosocial, electrophysiologic, and ergonomic risk factors. Active workers from six different sites were tested; five sites involved manufacturing workers, and one site represented clerical workers. One hundred eighty-four active workers with a median mononeuropathy were documented on nerve conduction studies. These workers represented a subset of more than 700 workers screened at six different locations. The main outcome measure was the patient's report of symptoms of pain, numbness, tingling or burning in the hand or fingers that lasted more than 1 week or occurred three or more times at the initial screening. Workers with a median mononeuropathy who complained of hand symptoms were more likely to be female, to have jobs with higher hand repetition levels, to have higher ratings of job security, not to have a history of diabetes, to use more force in their job with more abnormal postures of their wrist and fingers, and to have a trend toward a more prolonged median sensory distal latency. Most logistic regression models explained less than 15% of the variance (pseudo R2). Women with jobs that have higher ergonomic risks and no history of diabetes were more likely to have reported symptoms associated with carpal tunnel syndrome compared to other workers with a documented median mononeuropathy. Psychosocial variables were not particularly discriminatory. None of the models allows enough precision to predict on an individual basis.
Article
Incluye bibliografía e índice Reimprisión en 1992.
Article
In this investigation reported epidemiologic studies on carpal tunnel syndrome (CTS) (15 cross-sectional studies involving 32 occupational or exposure groups and six case-referent studies) were reviewed. The prevalence of CTS in the different occupational groups varied between 0.6 and 61%. The highest prevalence was noted for grinders, butchers, grocery store workers, frozen food factory workers, platers, and workers with high-force, high-repetitive manual movements. Odds ratios greater than 10 were reported for exposed groups in three studies. On the basis of epidemiologic and other evidence, it was concluded that exposure to physical work load factors, such as repetitive and forceful gripping, is probably a major risk factor for CTS in several types of worker populations. At least 50%, and as much as 90%, of all of the CTS cases in these exposed populations appeared to be attributable to physical work load.
Article
To study the prevalence of carpal tunnel syndrome (CTS) in the general population and the value of brachialgia paraesthetica nocturna (BPN) in diagnosing CTS, an age and sex stratified random sample of 715 subjects was taken from the population register of Maastricht (The Netherlands) and surrounding villages, between September 1983 and July 1985. The response rate was 70%. Of these, 12 CTS cases had already been diagnosed. Of the remaining subjects, 64 (13 men, 51 women) woke up because of BPN. Among these subjects 1 man and 23 women were found to have CTS. The prevalence rate of undetected CTS was 5.8% [95% confidence interval (CI): 3.5-8.1%] in adult women; 3.4 percent (95% CI: 1.5-5.3%) had already been diagnosed as CTS. The overall prevalence rate for men was 0.6% (95% CI 0.02-3.4%). These figures have to be regarded as minimal estimates. The overall diagnostic value of BPN for CTS was 38%, while for women only this was 45% (95% CI: 31-60%).