Accepted Manuscript Chronic neck pain in young adults: Perspectives on anatomic differences Ji-Hye Lee, Youn-Kwan Park, Joo-Han Kim PII:
S1529-9430(14)00241-1
DOI:
10.1016/j.spinee.2014.02.039
Reference:
SPINEE 55803
To appear in:
The Spine Journal
Received Date: 4 December 2011 Revised Date:
1 December 2013
Accepted Date: 9 February 2014
Please cite this article as: Lee J-H, Park Y-K, Kim J-H, Chronic neck pain in young adults: Perspectives on anatomic differences, The Spine Journal (2014), doi: 10.1016/j.spinee.2014.02.039. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Chronic neck pain in young adults: Perspectives on anatomic differences. Ji-Hye Lee, Youn-Kwan Park and Joo-Han Kim Neurosurgery, Korea University Guro Hospital, Seoul, Republic of Korea
RI PT
Corresponding author Youn-Kwan Park, MD Neurosurgery, Korea University Guro Hospital 80, Guro-dong, Guro ku, Seoul, 152-050, Republic of Korea Tel) 82-2-2626-3095
SC
Fax) 82-2-863-1684
AC C
EP
TE D
M AN U
Email) [email protected]
ACCEPTED MANUSCRIPT
1
Chronic neck pain in young adults: Perspectives on anatomic
2
differences Background context: Neck pain (NP) is a common musculoskeletal disorder, but little
4
is known about the associated risk factors.
5
Purpose: We compared anatomical differences in the neck and trunk area of young
6
adult patients with chronic neck pain and control subjects without neck pain to identify
7
risk factors and predictors.
8
Study Design: Age-, sex-, and BMI-matched retrospective case-control study of a
9
consecutive sample.
M AN U
SC
RI PT
3
Patient sample: Patients with axial NP for longer than 6 months (23 males and 25
11
females) and pain-free volunteers (23 males and 25 females).
12
Outcome measures: Linear and angular dimensions of the cervicothoracic juction
13
Methods: Mid-sagittal magnetic resonance imaging (MRI) scans of the cervicothoracic
14
spine were obtained. Four linear and four angular parameters were identified and
15
measured. These parameters included depth of the T1-manubrium arch (T1AD), depth of
16
the thoracic cage (TXD), tangential height of T1 (T1H1), relative height of T1 (T1H2), T1
17
slope (T1S), thoracic inlet inclination (TiI), T1-manubrium arch inclination (T1AI), and
18
the angular difference between TiI and T1AI (TiI -T1AI). The measurements were taken
19
by two neurosurgeons.
20
Results: T1AD and TiI were identified as predictors for NP in the binary logistic
21
regression analysis. Each mm increase in T1AD lessened the probability of NP with an
22
adjusted odds ratio (OR) of 0.823 (95% CI 0.701–0.966) in females and 0.809 (95% CI
23
0.681–0.959) in males. Each degree increase in TiI was associated with the probability
24
of NP with an adjusted OR of 1.247 (95% CI 1.060–1.466) in males.
AC C
EP
TE D
10
1
ACCEPTED MANUSCRIPT
Conclusions: Measurement of cervicothoracic junctional structures is a reliable and
2
feasible method of estimating potential predictor of chronic neck pain in young adults.
3
Forward inclination of the thoracic inlet in males and a shallow thoracic cage in females
4
were identified as important predictors.
RI PT
1
5
7
Keywords: Neck pain, Radiologic study, Gender differences, Thoracic cage dimension, Thoracic inlet inclination
SC
6
8 Introduction
M AN U
9
Chronic neck pain is a common musculoskeletal disorder. In adults, the mean point, 1
11
year, and lifetime prevalence estimates for neck pain have been reported to be 7.6%,
12
37.2%, and 48.5%, respectively [1]. Annually, 11 to 14.1% of workers report limited
13
activity as a result of neck pain [2]. Several studies have investigated the risk factors
14
associated with the development of chronic neck pain [3-10]. These include female
15
gender, older age, high job demands, low social/work support, ex-smoker, a history of
16
lower-back disorders, and a history of neck disorders [4]. Furthermore, metabolic
17
syndrome, which includes a high body mass index (BMI), is associated with neck pain,
18
particularly in males [10]. However, little is known regarding which individuals will
19
develop neck pain, particularly with regard to physical factors. Several studies have
20
suggested that head posture is closely related to neck pain [3, 5, 6, 9]. However, the
21
reliability and validity of this factor is controversial because the measurement is based
22
on surface anatomy [11].
23 24
AC C
EP
TE D
10
Over the past two decades, the importance of sagittal plane alignment for normal spine function and its role in the development of various disease states have become 2
ACCEPTED MANUSCRIPT
increasingly clear [12-18]. In particular, lumbar lordosis has been shown to be involved
2
in maintaining an upright posture and can be affected by pelvic morphology and
3
orientation. The present study extended this concept to the cervical spine as an
4
anatomical structure that may affect the development of neck pain. We focused on the
5
morphology of the upper thoracic cage, particularly the thoracic inlet, the arc consisting
6
of the manubrium, the first rib, and the first thoracic vertebra (T1) and the surrounding
7
area. To our knowledge, no previous study comparing sagittal alignment and the
8
dimensions of the thoracic inlet in males and females with and without chronic neck
9
pain has been reported. To identify the anatomical predictors for chronic neck pain, we
M AN U
SC
RI PT
1
10
compared the cervicothoracic junction in patients with and without chronic neck pain
11
using magnetic resonance imaging (MRI).
12 Materials and methods
14
A total of 96 young adults aged 20–40 years were enrolled in the present study. Of those,
15
48 were patients with chronic neck pain (23 males and 25 females) and 48 were pain-
16
free volunteers (23 males and 25 females). The neck-pain group consisted of
17
consecutively enrolled patients who had visited our outpatient clinic between January,
18
2009 and February, 2011 with persistent mechanical axial neck pain for more than 6
19
months and received a cervical spine MRI. All patients had a history of conservative
20
care at a primary care unit. Exclusion criteria included a history of neck injury,
21
neurological symptoms or signs, radiological abnormalities indicating cervical
22
radiculopathy or myelopathy, previous surgery for cervical disorders, and congenital
23
anomalies of the cervicothoracic spine. The pain-free subjects were age-, sex-, and
24
BMI-matched volunteers recruited from the community by means of announcements
AC C
EP
TE D
13
3
ACCEPTED MANUSCRIPT
about the study. The first round of volunteer recruitment occurred in September 2010,
2
and 16 subjects were recruited. The second round of volunteer recruitment took place
3
after enrolment of the patient group was completed, and the 32 volunteers were age-,
4
sex-, and BMI-matched. The inclusion criteria for the pain-free group included no
5
previous neck pain (lifetime-to-date), no medical history of a cervical spinal disorder or
6
cervical spinal surgery, and no radiological abnormalities detected prior to or during the
7
study. Age, sex, weight, and height were recorded, and BMI was calculated as the
8
weight in kilograms divided by the square of the height in meters. The degree of neck
9
pain experienced by the patients and its effect on everyday life were measured using a
10
Visual Analogue Scale (VAS) score for neck pain and the Neck Disability Index (NDI),
11
respectively.
SC
M AN U
12
RI PT
1
All participants underwent MRI scans of the spine in the supine position performed by technicians blinded to participant status. A standard foam headrest was
14
used to ensure that the cervical spine was in the same position for each participant. The
15
scans included mid-sagittal T2 images of the whole spine and the cervical spine. All
16
measurements were performed using a Picture Archiving and Communication System
17
(PACS). Four linear dimensions and four angular parameters were measured on each
18
mid-sagittal MRI scan. The parameters are shown in Table 1 and in Figures 1 and 2.
19
The MRI scans were presented in random order for assessment by two neurosurgeons
20
(Y.P and J.L.). One investigator (Y.P.) measured the MRI scans twice on two separate
21
occasions to evaluate intraobserver variation. Interobserver variation was assessed by a
22
second observer (J.L.) blinded to both participant status and the assessment of the other
23
observer. Variations in the results were analyzed using intraclass correlation coefficients
AC C
EP
TE D
13
4
ACCEPTED MANUSCRIPT
1
(ICCs, SPSS) and the Bland-Altman analysis (Analyse-it ver. 2.26, Analyse-it Software,
2
Leeds, UK).
3
The Statistical Package for the Social Sciences version 20 (SPSS, Chicago, IL, USA) was used to conduct the statistical tests. Morphology measurements were
5
summarized using means ± standard deviations (SD). Unpaired t-tests were used for the
6
primary comparisons between the painful and pain-free groups, stratified by sex. Odds
7
ratios (ORs) and 95% confidence intervals (CIs) for neck pain predictors were
8
calculated using multivariate logistic regression analysis with adjustments made for the
9
factors significantly associated with neck pain. Variables that had achieved significance
M AN U
SC
RI PT
4
levels of p
S1529-9430(14)00241-1
DOI:
10.1016/j.spinee.2014.02.039
Reference:
SPINEE 55803
To appear in:
The Spine Journal
Received Date: 4 December 2011 Revised Date:
1 December 2013
Accepted Date: 9 February 2014
Please cite this article as: Lee J-H, Park Y-K, Kim J-H, Chronic neck pain in young adults: Perspectives on anatomic differences, The Spine Journal (2014), doi: 10.1016/j.spinee.2014.02.039. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Chronic neck pain in young adults: Perspectives on anatomic differences. Ji-Hye Lee, Youn-Kwan Park and Joo-Han Kim Neurosurgery, Korea University Guro Hospital, Seoul, Republic of Korea
RI PT
Corresponding author Youn-Kwan Park, MD Neurosurgery, Korea University Guro Hospital 80, Guro-dong, Guro ku, Seoul, 152-050, Republic of Korea Tel) 82-2-2626-3095
SC
Fax) 82-2-863-1684
AC C
EP
TE D
M AN U
Email) [email protected]
ACCEPTED MANUSCRIPT
1
Chronic neck pain in young adults: Perspectives on anatomic
2
differences Background context: Neck pain (NP) is a common musculoskeletal disorder, but little
4
is known about the associated risk factors.
5
Purpose: We compared anatomical differences in the neck and trunk area of young
6
adult patients with chronic neck pain and control subjects without neck pain to identify
7
risk factors and predictors.
8
Study Design: Age-, sex-, and BMI-matched retrospective case-control study of a
9
consecutive sample.
M AN U
SC
RI PT
3
Patient sample: Patients with axial NP for longer than 6 months (23 males and 25
11
females) and pain-free volunteers (23 males and 25 females).
12
Outcome measures: Linear and angular dimensions of the cervicothoracic juction
13
Methods: Mid-sagittal magnetic resonance imaging (MRI) scans of the cervicothoracic
14
spine were obtained. Four linear and four angular parameters were identified and
15
measured. These parameters included depth of the T1-manubrium arch (T1AD), depth of
16
the thoracic cage (TXD), tangential height of T1 (T1H1), relative height of T1 (T1H2), T1
17
slope (T1S), thoracic inlet inclination (TiI), T1-manubrium arch inclination (T1AI), and
18
the angular difference between TiI and T1AI (TiI -T1AI). The measurements were taken
19
by two neurosurgeons.
20
Results: T1AD and TiI were identified as predictors for NP in the binary logistic
21
regression analysis. Each mm increase in T1AD lessened the probability of NP with an
22
adjusted odds ratio (OR) of 0.823 (95% CI 0.701–0.966) in females and 0.809 (95% CI
23
0.681–0.959) in males. Each degree increase in TiI was associated with the probability
24
of NP with an adjusted OR of 1.247 (95% CI 1.060–1.466) in males.
AC C
EP
TE D
10
1
ACCEPTED MANUSCRIPT
Conclusions: Measurement of cervicothoracic junctional structures is a reliable and
2
feasible method of estimating potential predictor of chronic neck pain in young adults.
3
Forward inclination of the thoracic inlet in males and a shallow thoracic cage in females
4
were identified as important predictors.
RI PT
1
5
7
Keywords: Neck pain, Radiologic study, Gender differences, Thoracic cage dimension, Thoracic inlet inclination
SC
6
8 Introduction
M AN U
9
Chronic neck pain is a common musculoskeletal disorder. In adults, the mean point, 1
11
year, and lifetime prevalence estimates for neck pain have been reported to be 7.6%,
12
37.2%, and 48.5%, respectively [1]. Annually, 11 to 14.1% of workers report limited
13
activity as a result of neck pain [2]. Several studies have investigated the risk factors
14
associated with the development of chronic neck pain [3-10]. These include female
15
gender, older age, high job demands, low social/work support, ex-smoker, a history of
16
lower-back disorders, and a history of neck disorders [4]. Furthermore, metabolic
17
syndrome, which includes a high body mass index (BMI), is associated with neck pain,
18
particularly in males [10]. However, little is known regarding which individuals will
19
develop neck pain, particularly with regard to physical factors. Several studies have
20
suggested that head posture is closely related to neck pain [3, 5, 6, 9]. However, the
21
reliability and validity of this factor is controversial because the measurement is based
22
on surface anatomy [11].
23 24
AC C
EP
TE D
10
Over the past two decades, the importance of sagittal plane alignment for normal spine function and its role in the development of various disease states have become 2
ACCEPTED MANUSCRIPT
increasingly clear [12-18]. In particular, lumbar lordosis has been shown to be involved
2
in maintaining an upright posture and can be affected by pelvic morphology and
3
orientation. The present study extended this concept to the cervical spine as an
4
anatomical structure that may affect the development of neck pain. We focused on the
5
morphology of the upper thoracic cage, particularly the thoracic inlet, the arc consisting
6
of the manubrium, the first rib, and the first thoracic vertebra (T1) and the surrounding
7
area. To our knowledge, no previous study comparing sagittal alignment and the
8
dimensions of the thoracic inlet in males and females with and without chronic neck
9
pain has been reported. To identify the anatomical predictors for chronic neck pain, we
M AN U
SC
RI PT
1
10
compared the cervicothoracic junction in patients with and without chronic neck pain
11
using magnetic resonance imaging (MRI).
12 Materials and methods
14
A total of 96 young adults aged 20–40 years were enrolled in the present study. Of those,
15
48 were patients with chronic neck pain (23 males and 25 females) and 48 were pain-
16
free volunteers (23 males and 25 females). The neck-pain group consisted of
17
consecutively enrolled patients who had visited our outpatient clinic between January,
18
2009 and February, 2011 with persistent mechanical axial neck pain for more than 6
19
months and received a cervical spine MRI. All patients had a history of conservative
20
care at a primary care unit. Exclusion criteria included a history of neck injury,
21
neurological symptoms or signs, radiological abnormalities indicating cervical
22
radiculopathy or myelopathy, previous surgery for cervical disorders, and congenital
23
anomalies of the cervicothoracic spine. The pain-free subjects were age-, sex-, and
24
BMI-matched volunteers recruited from the community by means of announcements
AC C
EP
TE D
13
3
ACCEPTED MANUSCRIPT
about the study. The first round of volunteer recruitment occurred in September 2010,
2
and 16 subjects were recruited. The second round of volunteer recruitment took place
3
after enrolment of the patient group was completed, and the 32 volunteers were age-,
4
sex-, and BMI-matched. The inclusion criteria for the pain-free group included no
5
previous neck pain (lifetime-to-date), no medical history of a cervical spinal disorder or
6
cervical spinal surgery, and no radiological abnormalities detected prior to or during the
7
study. Age, sex, weight, and height were recorded, and BMI was calculated as the
8
weight in kilograms divided by the square of the height in meters. The degree of neck
9
pain experienced by the patients and its effect on everyday life were measured using a
10
Visual Analogue Scale (VAS) score for neck pain and the Neck Disability Index (NDI),
11
respectively.
SC
M AN U
12
RI PT
1
All participants underwent MRI scans of the spine in the supine position performed by technicians blinded to participant status. A standard foam headrest was
14
used to ensure that the cervical spine was in the same position for each participant. The
15
scans included mid-sagittal T2 images of the whole spine and the cervical spine. All
16
measurements were performed using a Picture Archiving and Communication System
17
(PACS). Four linear dimensions and four angular parameters were measured on each
18
mid-sagittal MRI scan. The parameters are shown in Table 1 and in Figures 1 and 2.
19
The MRI scans were presented in random order for assessment by two neurosurgeons
20
(Y.P and J.L.). One investigator (Y.P.) measured the MRI scans twice on two separate
21
occasions to evaluate intraobserver variation. Interobserver variation was assessed by a
22
second observer (J.L.) blinded to both participant status and the assessment of the other
23
observer. Variations in the results were analyzed using intraclass correlation coefficients
AC C
EP
TE D
13
4
ACCEPTED MANUSCRIPT
1
(ICCs, SPSS) and the Bland-Altman analysis (Analyse-it ver. 2.26, Analyse-it Software,
2
Leeds, UK).
3
The Statistical Package for the Social Sciences version 20 (SPSS, Chicago, IL, USA) was used to conduct the statistical tests. Morphology measurements were
5
summarized using means ± standard deviations (SD). Unpaired t-tests were used for the
6
primary comparisons between the painful and pain-free groups, stratified by sex. Odds
7
ratios (ORs) and 95% confidence intervals (CIs) for neck pain predictors were
8
calculated using multivariate logistic regression analysis with adjustments made for the
9
factors significantly associated with neck pain. Variables that had achieved significance
M AN U
SC
RI PT
4
levels of p
