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Diagnostic accuracy of standardised qualitative sensory test in the detection of lumbar lateral stenosis involving the L5 nerve root

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Misdiagnosis of symptomatic lumbar lateral stenosis (LS) may result in an unfavourable prognosis after surgical treatment. This study investigated the diagnostic accuracy of a standardised qualitative sensory test (SQST) in the detection of symptomatic LS in patients who had degenerative spinal disorders involving the L5 spinal nerve. We prospectively identified 75 patients, of which 60 met the inclusion criteria. Lateral recess stenosis at the L5 level or foraminal stenosis at the L5/S1 level on MRI was identified and graded by a neurosurgeon blinded to any clinical information. The reference criteria for the diagnosis of symptomatic LS were grade III LS on MRI and relevant clinical symptoms. Cutaneous sensory functions of the L5 dermatome on the symptomatic side were evaluated using the SQST. Each item of the SQST showed a satisfactory performance in the diagnosis of LS (sensitivity = 0.455–0.727, specificity = 0.868–1.0). A stepwise selection model identified low-strength von-Frey, high-strength von-Frey, and vibration as the most accurate predictors of symptomatic LS with an area under the receiver operating characteristic curve of 0.9563 (95% confidence interval = 0.9003–1.0). In combination with MRI, the SQST is a promising diagnostic tool for detecting symptomatic LS involving L5 nerve roots.
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SCIeNTIfIC RepoRTS | 7: 10598 | DOI:10.1038/s41598-017-10641-2
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Diagnostic accuracy of standardised
qualitative sensory test in the
detection of lumbar lateral stenosis
involving the L5 nerve root
Jiann-Her Lin1,2,3,4, Yi-Chen Hsieh1, Yi-Chen Chen2, Yun Wang1, Chih-Cheng Chen4 &
Yung-Hsiao Chiang1,2,3
Misdiagnosis of symptomatic lumbar lateral stenosis (LS) may result in an unfavourable prognosis
after surgical treatment. This study investigated the diagnostic accuracy of a standardised qualitative
sensory test (SQST) in the detection of symptomatic LS in patients who had degenerative spinal
disorders involving the L5 spinal nerve. We prospectively identied 75 patients, of which 60 met the
inclusion criteria. Lateral recess stenosis at the L5 level or foraminal stenosis at the L5/S1 level on MRI
was identied and graded by a neurosurgeon blinded to any clinical information. The reference criteria
for the diagnosis of symptomatic LS were grade III LS on MRI and relevant clinical symptoms. Cutaneous
sensory functions of the L5 dermatome on the symptomatic side were evaluated using the SQST. Each
item of the SQST showed a satisfactory performance in the diagnosis of LS (sensitivity = 0.455–0.727,
specicity = 0.868–1.0). A stepwise selection model identied low-strength von-Frey, high-strength
von-Frey, and vibration as the most accurate predictors of symptomatic LS with an area under the
receiver operating characteristic curve of 0.9563 (95% condence interval = 0.9003–1.0). In combination
with MRI, the SQST is a promising diagnostic tool for detecting symptomatic LS involving L5 nerve
roots.
Degenerative lumbar spinal stenosis (LSS), the most common cause for lumbar spinal surgery in patients older
than 65 years1, is dened as “buttock or lower extremity pain, which may occur with or without low back pain,
associated with a diminished space available for neural and vascular elements in the lumbar spine, secondary
to degenerative lumbar spine diseases”2, 3. On the basis of anatomy, degenerative LSS can be classied as central
stenosis (CS) and lateral stenosis (LS)4. Lumbar LS can easily be overlooked, especially when there is coexisting
lumbar CS, and misdiagnosis of symptomatic LS may result in an unfavourable prognosis aer surgical treat-
ment5, 6. Because patients with LS and CS usually have similar clinical presentations7, 8, dierentiating LS from
CS on the basis of only clinical symptoms or signs is dicult. A prospective randomised study conducted in 1995
showed no dierences in symptoms, neurological ndings, or signs between LS and CS8. Since then, few studies
have examined dierences in clinical presentations between LS and CS. Only in 2014 did a comparative study
report that leg pain at rest was more severe in LS than in CS7.
In contrast to CS, LS involves the dorsal root ganglia and spinal nerves, which are more vulnerable to com-
pression and produce more severe neuropathic pain913. Neuropathic pain is redened as “pain arising as a direct
consequence of a lesion or disease aecting the somatosensory system”; this redenition was suggested by the
International Association for the Study of Pain Special Interest Group on Neuropathic Pain in 2008. A substantial
proportion of patients with chronic low back pain experienced a neuropathic pain component1416, and the most
frequently reported symptoms included hypoesthesia, allodynia, and radiating pain17. Standardised qualitative
sensory tests (SQSTs) described in the Standardised Evaluation of Pain (StEP)18 were validated to detect the neu-
ropathic component of low back pain19.
1PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical
University and National Health Research Institutes, Taipei, Taiwan. 2Department of Neurosurgery, Taipei Medical
University Hospital, Taipei, Taiwan. 3Division of Neurosurgery, Department of Surgery, School of Medicine, College
of Medicine, Taipei Medical University, Taipei, Taiwan. 4Institute of Biomedical Sciences, Academia Sinica, Taipei,
Taiwan. Correspondence and requests for materials should be addressed to Y.-H.C. (email: ychiang@tmu.edu.tw)
Received: 19 April 2017
Accepted: 14 August 2017
Published: xx xx xxxx
OPEN
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On the basis of the ndings of the aforementioned studies, we hypothesised that patients with symptomatic
LS have a higher incidence of abnormal SQST results than do those without symptomatic LS, and an SQST
combined with magnetic resonance imaging (MRI) can help physicians in the diagnosis of symptomatic LS. is
study investigated the diagnostic accuracy of an SQST in the detection of symptomatic LS in patients who had
degenerative spinal disorders at the L4/5 or L5/S1 level with disabling back and leg pain.
Methods
Design. is was a cross-sectional diagnostic study. All data were prospectively collected at our hospital from
April 2016 to February 2017. is study was approved by the Taipei Medical University Joint Institutional Review
Board (N201602059). All procedures in this study were performed in accordance with relevant guidelines and
regulations, and informed consent was obtained from all participants or their legal guardians.
Study population. We identied patients older than 18 years who had disabling back pain with or without
leg pain and were admitted to our hospital for lumbar spinal surgeries under the care of a single surgeon. Patients
who met the following criteria were included: (1) back pain with or without leg pain lasting for more than 3
months aer conservative treatment and (2) a corresponding lesion on MRI, such as (a) central spinal stenosis at
the L4/5 level due to spondylolisthesis or disc herniation, (b) lateral recess stenosis at the L5 level, (c) foraminal
stenosis at the L5/S1 level, or (d) segmental instability requiring surgical treatment at the L4/5 level. We excluded
patients who had received a diagnosis of a spinal tumour or infection, presented with cauda equina syndrome,
refused to undergo the SQST, had a visual analogue scale (VAS) score of less than 2 for leg pain or soreness, or
had simultaneous involvement of L5 nerve roots on both sides. e SQST was designed to examine dierences
between the symptomatic and contralateral sides; thus, patients with bilateral L5 nerve root involvement may
have normal SQST results. To particularly focus on the L5 nerve, we excluded patients who had only L4/5 foram-
inal stenosis or L5/S1 CS and those with a pathology not involving the L4/5 or L5/S1 level.
Baseline measures. e SQST was performed according to the standard protocol described in the StEP18,
except that we used 10 °C for the cold test. In our preliminary study, patients felt a clear cold sensation on their
dorsal feet only until the temperature of water was less than 10 °C in a closed room with a temperature of 24–27 °C,
and at 10 °C, they could clearly report a dierence between the two sides if there was a sensory disturbance. When
the temperature of water was 15–20 °C, they felt moderately cold and could hardly identify the dierence in cold
sensation between the two sides, even when other sensory tests strongly suggested a sensory disturbance. All
tests were performed in a quiet room with the temperature maintained at 24–27 °C, and the patients were asked
to sit on a chair with their naked feet comfortably situated on a leg rest. e skin of their medial dorsal foot was
regarded as the L5 dermatome and the test area. is area was suggested as the L5 dermatome by a study com-
bining clinical symptoms, electromyography, and imaging and surgical ndings20. A complete SQST comprised
eight sensory tests. For each sensory test, an abnormal nding was dened as decreased sensation or hyperalgesia
on the symptomatic side compared with the contralateral side, whereas a normal nding was dened as the same
sensation between both sides. An investigator (a physician assistant, the third author) interviewed all patients
and performed the SQST. Before this study, two investigators (a neurosurgeon, the rst author, and the physician
assistant, the third author) evaluated the interrater and intrarater agreements of 18 patients. e interrater agree-
ment of each item of the SQST and SLRT was 0.6–1, and the intrarater agreement was 0.7692–1 (Supplemental
Table1).
Lumbar spine MRI. All lumbar spine MRI examinations were performed using a 1.5 T MR scanner (Signa, GE
Healthcare, Waukesha, WI, USA) with a traditional cervical–thoracic–lumbar spine coil (Signa, GE Healthcare)
at the study hospital. The patients were placed in a supine position with a cushion under both knees, and
T2-weighted fast spin-echo axial and sagittal images were obtained (repetition time/echo time, 3000.00/110.00
ms and 3050.00/110.00 ms; eld of view, 18 cm and 30 cm; matrix, 320°–224° and 384°–214°; echo train length,
20 and 25; excitations, 3–4 and 4 for axial and sagittal scans, respectively; slice thickness, 4 mm; slice gap, 0.4 mm;
and ip angle, 90°).
Reference criteria: Symptomatic LS. e reference criteria for the diagnosis of symptomatic LS were a
grade III LS on MRI and clinical symptoms (radiating or shooting pain below the knee or L5 dermatomal pain
distribution). A neurosurgeon (the rst author) graded the LS and CS of each patient and then classied each
patient as having LS or CS or no stenosis based on MRI ndings. is observer was unaware of the patient’s med-
ical history or the results of SQSTs. e observer had 8 years of postresidency experience in reading spinal MRIs.
CS was dened as central spinal stenosis at the L4/5 level caused by spondylolisthesis or disc herniation and was
graded according to Schizas’s and Lee’s classication21, 22. CS was regarded to be present if the grade was B, C, or
D according to Schizas’s classication (Fig.1). LS was dened as lateral recess stenosis at the L5 level or foraminal
stenosis at the L5/S1 level23 (Fig.1). Lateral recess stenosis was graded according to Bartynski’s classication24,
and foraminal stenosis was graded following Lees classication25. LS diagnosis was a radiological diagnosis based
only on imaging grading; however, diagnosis of symptomatic LS was a clinical diagnosis based on both imaging
grading and clinical symptoms. LS was regarded as present if the grade of lateral recess stenosis or foraminal
stenosis was 3. In addition, the diagnosis of symptomatic LS in this study was made by a senior neurosurgeon
who had 40 years of experience in the management of degenerative lumbar stenosis based on clinical symptoms
(radiating or shooting pain below the knee or L5 dermatomal pain distribution) and corresponding grade III
lateral recess stenosis or grade III foramina stenosis on MRI. In this study, the foraminal stenosis or lateral recess
stenosis of patients with symptomatic LS was surgically conrmed, and their leg pain improved immediately aer
the surgery.
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Clinical information collection. We prospectively collected the data of all patients, including age, sex, diag-
nosis, results of the preoperative Short Form-36 (SF-36; Chinese version)26, the Japanese Orthopedic Association
(JOA) score for low back pain27, the Oswestry disability index (ODI; Chinese version)28, and VAS scores for leg
pain or soreness, or back pain or soreness (the scale ranged from 0 to 10, with 0 indicating “no pain at all” and 10
indicating “the most imaginable pain”). We regarded soreness as a discomfort in patients with symptomatic LS.
Statistical analysis. Data are presented as the mean ± standard deviation. Comparisons between continu-
ous variables (age, SF-36, ODI, and JOA) were performed using the Student t test, one-way analysis of variance
(ANOVA), and the Mann–Whitney U test. Comparisons between categorical variables (sex, level, diagnosis,
stenosis grade, and SQST results) were performed using the chi-square test. e Holm–Sidak correction method
was used for multiple comparisons. Logistic regression models were used to evaluate the receiver operating char-
acteristic (ROC) curve for various sensory and test assessments to identify LS. e areas under the curves (AUCs)
indicated the highest possible sensitivity and specicity. A stepwise model selection method was used to conrm
Stenosis type
Lateral Stenosis
pWith Without
n 22 38
Age 56.45 ± 15.5 66.26 ± 10.9 0.0920
Gender
F10 28 0.0500
M12 10
Diagnosis
Disc herniation 12 10 0.1027
Spondylolisthesis 9 25
Spondylosis 2 4
Back pain 5.32 ± 3.22 5.84 ± 3.41 0.9982
Back soreness 4.29 ± 3.81 4.54 ± 3.45 0.1967
Leg pain 7.27 ± 2.68 5.00 ± 3.65 0.9982
Leg soreness 2.57 ± 3.57 4.00 ± 3.18 0.9314
SF36
Physical Functioning 24.8 ± 16.6 17.39 ± 13.5 0.6381
Role-Physical 30.44 ± 7.08 29.42 ± 5.43 0.9982
Role-Emotional 36.69 ± 9.66 36.6 ± 9.75 0.9982
Bodily Pain 25.79 ± 10.5 26.35 ± 7.89 0.9982
Vitality 41.16 ± 10.8 38.88 ± 9.64 0.9965
Mental Health 45.5 ± 10.9 41.96 ± 11.6 0.9760
Social Functioning 35.7 ± 13.1 33.43 ± 12.4 0.9982
General Health 42.37 ± 10.2 40.98 ± 11.4 0.9982
AGG_Physics 21.57 ± 11.8 18.95 ± 9.72 0.9950
AGG_Mental 47.38 ± 9.91 45.61 ± 10.9 0.9982
ODI 23.43 ± 9.68 21.67 ± 6.46 0.9978
JOA 16.79 ± 4.76 17.53 ± 3.77 0.9982
Table 1. Comparison of lateral stenosis(+) and lateral stenosis() groups.
Figure 1. e arrows indicate Schizas’s grade D central stenosis (a) and grade III lateral recess stenosis (b) on
axial T2-weighted magnetic resonance images, and grade III foraminal stenosis (c) on a sagittal T2-weighted
magnetic resonance image.
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logistic regression as the best method to build a predictive model. Statistical analyses were performed using Prism
7 for Mac (GraphPad Soware, La Jolla, CA, USA) and SAS soware, version 9.4 (SAS Institute, Cary, NC).
Availability of materials and data. e datasets generated and/or analysed during the current study are
available from the corresponding author on reasonable request.
Results
Between April 2016 and February 2017, 75 patients were assessed for eligibility (Fig.2). Of these patients, 15 were
excluded for the following reasons: 1 patient refused to undergo the SQST, 13 had a VAS score of less than 2 for
leg pain or soreness, and 1 had bilateral L5 nerve root involvement. Finally, 60 patients were included. According
to the presence of symptomatic LS (grade III LS on MRI and patients’ clinical symptoms), 22 and 38 patients were
included into the LS(+) and LS() groups, respectively. In the LS(+) group, 12 patients had only LS and 10 had
both CS and LS. By contrast, in the LS() group, 34 patients had only CS, and 4 had no stenosis. No signicant
dierence was observed between the LS(+) and LS() groups in age, diagnosis, back pain, back soreness, leg
pain, leg soreness, SF-36 score, ODI, or JOA score, but a dierence was observed in sex (Table1). In the sub-
group analysis, no signicant dierence was observed among the four groups (Supplementary TableS2). In the
LS(+) group, 15 patients had lateral recess stenosis (graded as 3) and 7 patients had foraminal stenosis (graded
as 3), whereas in the LS() group, the stenosis of 4, 8, 18, and 8 patients was graded as A, B, C, and D, respec-
tively, according to Schizas’s classication (Table2). e stenosis type signicantly diered between the LS(+)
and LS() groups (Table2). Kappa values for the intrarater and interrater agreements of the SQST are listed in
Supplementary TableS1, and the agreement of all items was good to excellent. ncidence of sensory disturbance
in each item of the SQST in patients with LS than in patients without LS (73% vs. 8% for low-strength von-Frey,
p < 0.0001; 73% vs. 3% for high-strength von-Frey, p < 0.0001; 55% vs. 0% for pinprick, p < 0.0001; 45% vs. 0% for
brush, p < 0.0001; 59% vs. 3% for blunt, p < 0.0001; 59% vs. 8% for vibration, p < 0.0001; 68% vs. 3% for warmth,
p < 0.0001; and 73% vs. 16% for cold, p < 0.0001; Supplement Table3).
Table3 lists the AUC, sensitivity, specicity, positive predictive values, and negative predictive values of the
SQST for symptomatic LS. e sensitivity and specicity of the diagnosis of LS on MRI were 72.7% and 92.1%
for low-strength von-Frey, 72.7% and 97.4% for high-strength von-Frey, 54.5% and 100% for pinprick, 45.5% and
100% for brush, 59.1% and 97.4% for blunt, 59.1% and 92.1% for vibration, 68.2% and 97.4% for warmth, and
59.1% and 86.8% for cold, respectively. All eight items of the SQST were then chosen in the stepwise selection pro-
cedure. e nal model identied low-strength von-Frey, high-strength von-Frey, and vibration as the most accu-
rate predictors of LS with an area under the ROC curve of 0.9563 (95% condence interval = 0.9003–1.0; Fig.3).
Discussion
e results of this study demonstrated that among patients with a pathology at the L4/5 or L5/S1 level involv-
ing the L5 spinal nerve root, those with symptomatic LS had a higher incidence of abnormal SQST results, and
low-strength von-Frey, high-strength von-Frey, and vibration were identied to be the most accurate predictors
of symptomatic LS.
Figure 2. Flowchart of the inclusion of eligible patients. CS, central stenosis; LS, lateral stenosis; SQST,
standardised qualitative sensory test.
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e current study is the rst to show that the SQST is a useful tool for dierentiating patients with sympto-
matic LS from those with CS. Typically, patients with CS have more pain in the back than in the legs, whereas
those with LS have more pain in the legs than in the back. However, the identication of symptomatic LS is di-
cult when it coexists with CS and when patients have pain in both the back and legs. erefore, we included only
patients who had a VAS of more than 2 for leg pain or soreness in this study. A few studies have compared clinical
presentations between LS and CS. Leg pain at rest was reported to be more severe in patients with LS compared
with those with CS7. In agreement with this nding, we found a trend of leg pain being more severe in patients
with LS, but the dierence was not statistically signicant. However, a prospective randomised trial showed that
sensory disturbances did not dier between patients with LS and those with CS8. In contrast to this nding, our
study results revealed that patients with symptomatic LS had a signicantly higher incidence of abnormal SQST
results. We believe that the standardised protocol of the SQST in the StEP improved the sensitivity and specicity
of the diagnosis of symptomatic LS in our study. Furthermore, symptomatic LS is easily overlooked, particularly
when there is coexisting CS. In our study, 10 patients had both CS and LS, and all of them exhibited sensory dis-
turbances in at least one item of the SQST in their aected limb. Patients with both CS and LS had more LS-like
clinical presentations. Compared with patients with only CS, more patients with both CS and LS had abnormal
ndings in SQSTs (Supplementary TableS3), and the SQST is a promising tool in the diagnosis of LS, even when
there is coexisting CS.
Lateral stenosis
pYes No
Central stenosis (L4/5
spinal canal) 22 38
Schiza 0.0012
A 12 4
B 5 8
C 3 18
D 2 8
Lee 0.0045
0 9 4
1 5 4
2 3 4
3 5 26
Lateral stenosis
L5 lateral recess <0.0001
0 3 14
1 1 12
2 3 12
3 15 0
L5/S1 foraminal stenosis 0.0027
0 11 25
1 1 5
2 3 8
3 7 0
Table 2. Grading of central stenosis and lateral stenosis in lateral stenosis(+) and lateral stenosis() groups.
Variables AUC Sensitivity Specicity PPV NPV
Low Strength
von frey 0.82 (0.72–0.93) 0.82 (0.72–3.93) 0.92 (0.84–1.01) 0.84 (0.68–1.01) 0.85(0.75–0.96)
High Strength
von frey 0.85 (0.75–0.95) 0.73 (0.54–0.91) 0.97 (0.92–1.03) 0.94 (0.83–1.05) 0.86 (0.76–0.96)
Pinprick 0.77 (0.67–0.88) 0.55 (0.34–0.75) 1.00 (1.00–1.00) 1.00 (1.00–1.00) 0.79 (0.68–0.91)
Brush 0.73 (0.62–0.83) 0.46 (0.25–0.66) 1.00 ((1.00–1.00) 1.00 (1.00–1.00) 0.76 (0.76–0.88)
Blunt 0.78 (0.67–0.89) 0.59 (0.39–0.80) 0.97 (0.92–1.03) 0.93 (0.79–1.06) 0.80 (0.69–0.99)
Vibration 0.76 (0.64–0.87) 0.59 (0.39–0.80) 0.92 (0.94–1.01) 0.81 (0.62–1.00) 0.80 (0.68–0.92)
War m 0.83 (0.73–0.93) 0.68 (0.49–0.88) 0.97 (0.92–1.03) 0.94 (0.82–1.06) 0.84 (0.73–0.95)
Cold 0.73 (0.61–0.85) 0.59 (0.39–0.80) 0.87 (0.76–0.98) 0.72 (0.52–0.93) 0.79 (0.66–0.91)
Table 3. AUC, sensitivity, specicity, PPV, and NPV of the SQST in the detection of lateral stenosis. AUC, area
under the curve; PPV, positive predictive value; NPV, negative predictive value; SQST, standardised qualitative
sensory test; SLRT, straight leg rising test. Corresponding 95% condence intervals are in parentheses.
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In our study, patients with symptomatic LS had a higher incidence of abnormal ndings in the SQST, which
are indicators of neuropathic pain. Neuropathic pain refers to pain arising as a direct consequence of a lesion or
disease aecting the somatosensory system29. Low back pain may comprise both nociceptive axial and neuro-
pathic radicular pain. In patients with such pain, dierentiating between nociceptive and neuropathic pain is
clinically important, because these components require dierent pain management strategies. is denition
has been useful to distinguish between neuropathic and other types of pain; however, it lacks both diagnostic
specicity and anatomic precision3035. Consequently, a grading system was proposed to provide a more precise
denition useful for clinical and research purposes29, 36. e proposed grading system is based on the certainty of
neuropathic pain and has four criteria:
1. Pain with a distinct neuroanatomically plausible distribution.
2. A history suggestive of a relevant lesion or disease aecting the peripheral or central somatosensory
system.
3. e presence of negative or positive neurological signs concordant with the distribution of pain in neuro-
logical examination or in the more objective conrmatory tests (quantitative sensory testing or laboratory
tests).
4. Demonstration of the relevant lesion or disease by at least one conrmatory test.
e grading of certainty for the presence of neuropathic pain is considered “dened” if all criteria are met,
“probable” if both criteria 1 and 2 plus either 3 or 4 are met, and “possible” if only 1 and 2 are met without con-
rmatory evidence from 3 or 4.
In this study, on the basis of the grading system of neuropathic pain, we modied these four criteria for grad-
ing neuropathic pain in lumbar radiculopathy specically involving the L5 spinal nerve:
1. Leg pain below the knee along or not along the L5 dermatome.
2. A history of low back pain or leg pain.
3. Abnormal ndings in the SQST.
4. Stenosis showing the involvement of the L5 dorsal nerve root or dorsal root ganglion on MRI.
Leg pain in patients with stenosis, particularly LS, and abnormal ndings in the SQST were classied as
denied neuropathic pain (all criteria were satised). Leg pain in those with stenosis but with normal ndings
in the SQST was dened as probable neuropathic pain. Leg pain in those without either stenosis or abnormal
Figure 3. Low-strength von-Frey, high-strength von-Frey, and vibration were identied to be the most accurate
predictors of lateral stenosis through a stepwise selection procedure with an area under the receiver operating
characteristic curve of 0.9563 (95% condence interval = 0.9003–1.0).
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ndings in the SQST was dened as possible neuropathic pain. Accordingly, leg pain in 100% of patients with
symptomatic LS and 18% of patients with CS was denite neuropathic pain. Leg pain in 82% of patients with CS
was probable neuropathic pain and that in four patients without LS or CS was possible neuropathic pain. e
risk of nerve root injury is higher in LS than in CS because of the anatomic structures. In contrast to the central
canal, the lateral canal has a much narrower space; thus, nerve root injury can easily occur in LS. In addition,
nerve structures involved in LS and CS are dierent. In LS, the dorsal root ganglia and their spinal nerves are
involved, and injuring these structures caused much severer pain responses in an animal model compared with
injury of dorsal roots in the central canal913. In summary, the relatively narrow anatomical structures and the
nerve structures comprising the lumbar lateral canal may underpin the mechanism that explains why patients
with symptomatic LS have more abnormal sensory test results and neuropathic pain.
We dened grade 3 as the presence of LS in both the lateral recess and foramen. e grade at which LS causes
symptoms remains controversial. Grades II and III were dened as the presence of stenosis in a previous study24.
In our study, 25% (4/16) of patients with grade II LS and 95.5% (21/22) of patients with grade III LS exhibited
abnormal SQST results. Although four patients with grade II LS had abnormal SQST results, their leg pain was
not more severe than their back pain, was not in a radiating or shooting manner, and did not extend below the
knees. On the basis of their clinical presentations, a diagnosis of symptomatic LS was not established. Accordingly,
grade III was dened as the presence of LS, not including grade II. e VAS scores for leg pain of patients with
grade 0–1 LS, grade 2 LS, and grade 3 LS were 4.86 ± 3.73, 5.19 ± 3.66, and 7.23 ± 2.68, respectively (one-way
ANOVA, p = 0.047). e VAS score for leg pain increased with the grade of LS. Accordingly, the results of the
current study showed that grade 3 LS in either the lateral recess or foramen is more likely to result in abnormal
sensory test results or leg symptoms.
LS consisted of lateral recess stenosis and foraminal stenosis. A study reported 72% sensitivity of MRI in
the detection of Grade II–III lateral recess stenosis related to the degenerative bony changes of the surrounding
structure, but it excluded stenosis related to disc protrusion24. In other words, the sensitivity of MRI in the detec-
tion of lateral recess stenosis related to disc protrusion is not known. Another study reported that the sensitivity,
specicity, and accuracy of MRI in the detection of a lumbar disc protrusion is 92%, 91%, and 92%, respectively,
which was conrmed by surgical ndings37. us, we believe that MRI can more accurately detect lateral recess
stenosis related to disc protrusion compared with that related to degenerative bony changes. In this study, 67%
of grade III lateral recess stenosis was related to disc protrusion, and 33% was related to degenerative facet joint
hypertrophy or pars interarticularis hypertrophy. Grade III lateral recess stenosis shown on preoperative MRI of
all patients was surgically conrmed in our study. In patients with grade 0–II lateral recess stenosis, a disc protru-
sion or very severe stenosis related to the bony structure was not found at the lateral recess during the operation,
but it was very dicult to grade lateral recess stenosis intraoperatively. ereaer, a bias may have occurred due to
our underestimation of the incidence of grade II or III LS related to degenerative bony changes in patients in the
LS() group. However, for lateral recess stenosis related to disc protrusion, the bias was very limited.
is study has some limitations. Although the number of participants was small, and condence intervals
around the estimates of sensitivity, specicity, and positive and negative predictive values were therefore slightly
wide, the power was still satisfactory (87.29%) when we considered the cold sensory test with the smallest ROC
curve (0.73). is study included only patients who experienced disabling pain for more than 3 months; thus,
the results of the SQST in patients with acute pain would not necessarily be the same. e focus of this study was
to identify symptomatic LS. For asymptomatic LS, the SQST was not validated in this study. All patients were
recruited from a single hospital, and local factors inuencing the incidence of lumbar LS cannot be excluded.
erefore, the generalisability of our results may be limited. e SQST is used to detect dierences in sensation
between two sides. us, it may be not able to detect dierences in a patient who has sensory disturbance on both
sides. e SQST is a qualitative test, and it cannot reect how dierent patients feel between sides. e accuracy
of the SQST is based on patients’ responses, and it heavily depends on patients’ understanding and cooperation.
is study excluded patients who could not respond correctly to the SQST. In addition, the L5 dermatome may
vary among patients. e skin site tested in this study was the medial dorsal foot, which was regarded as the L5
dermatome in a comprehensive study combining clinical symptoms, electromyography, and imaging and surgical
ndings20. However, the medial dorsal foot may not be the L5 dermatome in a few patients. e results of this
study should be interpreted with caution. Finally, because MRI has only 72% sensitivity in the detection of grade
II–III lateral recess stenosis related to the degenerative bony structure, a bias may have occurred in this study
due to the underestimation of the incidence of such stenosis. However, for lateral recess stenosis related to disc
protrusion and foraminal stenosis, underestimation was limited.
Conclusions
e incidence of abnormal sensory test results was higher in patients with symptomatic LS than in those with
CS. e results of this study indicated that in combination with MRI, the SQST can serve as a diagnostic tool in
the identication of symptomatic LS in patients with symptomatic lumbar stenosis involving the L5 spinal nerve.
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Acknowledgements
is study received a grant from the Ministry of Science and Technology, Taiwan (MOST 104-2314-B-038-034
and MOST 106-2321-B-001-044 to Jiann-Her Lin).
Author Contributions
Jiann-Her Lin wrote the main manuscript; Yi-Chen Hsieh performed the statistical analysis; Yi-Chen Chen
collected patients’ data; Yun Wang, Chih-Chen Chen, and Yung-Hsiao Chiang supervised the study; and Yung-
Hsiao Chiang provided administrative support.
Additional Information
Supplementary information accompanies this paper at doi:10.1038/s41598-017-10641-2
Competing Interests: e authors declare that they have no competing interests.
Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and
institutional aliations.
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Supplementary resource (1)

... Another novel hypothesis is large-diameter sensory afferent injury. Several studies showed that the involvement of large-diameter sensory afferents is associated with the severity of peripheral nerve injury [5,12]. The expression of CGRP in large-diameter sensory afferents was associated with the positive neuropathic syndrome [12]. ...
... Plastic changes in the electrophysiological property of large-diameter sensory afferents were demonstrated under pathological pain status [29]. A prospective cohort of 75 patients with LR revealed that defect of sensations conducted by large-diameter sensory afferents was associated with more severe symptoms [5]. This study indicated more ATF3-expressing DRG neurons, especially NFH subpopulation, in distal nerve constriction and supported that large-diameter sensory afferent injury contributes to pain chronicity in distal nerve constriction as compared with proximal nerve constriction. ...
... At present, there is not a factor predicting pain chronicity in LR. A nation-wide cohort showed severe LR is associated with pain chronicity [4], and 2 studies suggested that involvement of large-diameter sensory afferents could serve as an index of severity of peripheral nerve injury [5,12]. The present study provided evidence that largediameter sensory afferent injury contributes to persistent pain in LR. ...
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The mechanism of pain chronicity is largely unknown in lumbar radiculopathy (LR). The anatomical location of nerve injury is one of the important factors associated with pain chronicity of LR. Accumulating evidence has shown constriction distal to the dorsal root ganglion (DRG) caused more severe radiculopathy than constriction proximal to the DRG; thereby, the mechanism of pain chronicity in LR could be revealed by comparing the differences in pathological changes of DRGs between nerve constriction distal and proximal to the DRG. Here, we used 2 rat models of LR with nerve constriction distal or proximal to the DRG to probe how the different nerve injury sites could differentially affect pain chronicity and the pathological changes of DRG neuron subpopulations. As expected, rats with nerve constriction distal to the DRG showed more persistent pain behaviors than those with nerve constriction proximal to the DRG in 50% paw withdraw threshold, weight-bearing test, and acetone test. One day after the operation, distal and proximal nerve constriction showed differential pathological changes of DRG. The ratios of activating transcription factor3 (ATF3)-positive DRG neurons were significantly higher in rats with nerve constriction distal to DRG than those with nerve constriction proximal to DRG. In subpopulation analysis, the ratios of ATF3-immunoreactivity (IR) in neurofilament heavy chain (NFH)-positive DRG neurons significantly increased in distal nerve constriction compared to proximal nerve constriction; although, both distal and proximal nerve constriction presented increased ratios of ATF3-IR in calcitonin gene-related peptide (CGRP)-positive DRG neurons. Moreover, the nerve constriction proximal to DRG caused more hypoxia than did that distal to DRG. Together, ATF3 expression in NHF-positive DRG neurons at the acute stage is a potential bio-signature of persistent pain in rat models of LR.
... More simple nonautomated QST approaches and sensory mapping techniques have also been suggested to address this problem [7]. Furthermore, the qualitative sensory testing principle was proposed and tested for the detection of atypical odontalgia [8], stenosis involving the L5 nerve root [9], and for assessment of nerve block quality with local anesthetic [10]. ...
... Intact sensory function or a relatively low degree of sensory impairment difficult to distinguish from the unaffected side of the body are among possible explanations. Qualitative type of sensory testing in patient populations with unilateral sciatica [15], in lumbar nerve-root compression syndromes [16], in radicular pain patients [17], or symptomatic lumbar lateral stenosis involving L5 root [9] showed similar frequencies (27% to 55%) of normal sensitivity. ...
... While hypersensitivity phenomena were common in one report with qualitative type testing study [18], some other studies with QST report hypersensitivity as a rare finding [17,19,20]. Some other radiculopathy studies did not record hypersensitivity or included them in the general group of "sensory impairments" [9]. Sensory hypersensitivity is a marker of nervous system sensitization [21]. ...
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Background. Somatosensory testing could be useful in stratifying pain patients and improving pain treatment guidelines. Bedside-suitable techniques are searched for application in daily clinical practice. This study aimed to characterize chronic unilateral lumbosacral radiculopathy (LSR) patients with radicular pain using multimodal bedside-suitable somatosensory testing. Materials and methods. We evaluated 50 chronic unilateral LSR patients with radicular pain (LSR group) and 24 controls (Control group). Sensory testing was performed using a battery of bedside sensory tests (10g monofilament, 200–400 mN brush, Lindblom rollers with controlled 25°C and 40°C temperature, and 40g neurological pin and investigator’s finger pressure). Participants had to rate their sensory perceptions on both legs at multiple test points within L3 to S2 dermatomes. Characteristics of the testing process and sensory disturbances were analyzed. Results. LSR group showed sensory disturbances in 82% of patients. The Control group showed no sensory disturbances. Sensory testing took longer (p < 0.001) in the LSR group (29.3 ± 6.5 minutes per patient) than in the Control group (20.5 ± 5.2). Nine sensory phenotypes were detected in the LSR group according to individual sensory disturbances within 5 superficial tests. Conclusions. The applied multimodal bedside-suitable somatosensory testing battery is suitable for sensory evaluation and characterization of LSR patients. Grouping of allied sensory phenotypes revealed some tendencies in pain intensity characteristics.
... However, these tools are yet to be validated in identifying NP in LBLP and, the literature regarding superiority of one over the other is varied and conflicting [13,15]. Similarly, research investigating the use of patient history and clinical examination items to diagnose NP in LBLP is lacking and inconclusive [16,17]. Two separate studies have devised a list of clinical indicators using patient history and clinical examination items to identify peripheral NP in patients with or without leg pain [18] and in lumbosacral nerve root compression [19]. ...
... One study did not report the age of participants [33]. The phenomena of interest varied significantly between studies; two studies investigated lumbosacral nerve root compression [19,34], one study investigated participants with upper/mid lumbar nerve root compression [32] and another looked specifically at L5 lateral stenosis [17]. Two studies investigated peripheral NP and chronic low back pain respectively [18,30] with and without leg pain, whereas Capra et al. [16] investigated sciatica with or without lumbar pain. ...
... One study investigated the diagnostic accuracy of patient history data [34], whilst two studies investigated both patient history data and clinical examination data [18,19]. Finally the remaining six studies investigated the use of clinical examination tests; Straight leg raise (SLR) [16], Slump test [33], slump knee bend [32], nerve palpation [35], standardised qualitative sensory testing (SQST) [17], and bell test/hyperextension test [31]. ...
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Background: Low back-related leg pain (LBLP) is a challenge for healthcare providers to manage. Neuropathic pain (NP) is highly prevalent in presentations of LBLP and an accurate diagnosis of NP in LBLP is essential to ensure appropriate intervention. In the absence of a gold standard, the objective of this systematic review was to evaluate the diagnostic utility of patient history, clinical examination and screening tool data for identifying NP in LBLP. Methods: This systematic review is reported in line with PRISMA and followed a pre-defined and published protocol. CINAHL, EMBASE, MEDLINE, Web of Science, Cochrane Library, AMED, Pedro and PubMed databases, key journals and the grey literature were searched from inception to 31 July 2019. Eligible studies included any study design reporting primary diagnostic data on the diagnostic utility of patient history, clinical examination or screening tool data to identify NP in LBLP, in an adult population. Two independent reviewers searched information sources, assessed risk of bias (QUADAS-2) and used GRADE to assess overall quality of evidence. Results: From 762 studies, 11 studies were included. Nine studies out of the 11 were at risk of bias. Moderate level evidence supports a cluster of eight signs (age, duration of disease, paroxysmal pain, pain worse in leg than back, typical dermatomal distribution, worse on coughing/sneezing/straining, finger to floor distance and paresis) for diagnosing lumbosacral nerve root compression, demonstrating moderate/high sensitivity (72%) and specificity (80%) values. Moderate level evidence supports the use of the StEP tool for diagnosing lumbar radicular pain, demonstrating high sensitivity (92%) and specificity (97%) values. Conclusions: Overall low-moderate level evidence supports the diagnostic utility of patient history, clinical examination and screening tool data to identify NP in LBLP. The weak evidence base is largely due to methodological flaws and indirectness regarding applicability of the included studies. The most promising diagnostic tools include a cluster of 8 patient history/clinical examination signs and the StEP tool. Low risk of bias and high level of evidence diagnostic utility studies are needed, in order for stronger recommendations to be made.
... In the study of Lin et al. 30 SQST was found to have low/ moderate sensitivity (62%) and high specificity (95%) when detecting lumbar lateral stenosis of the L5 nerve root. However, indirectness of evidence was highlighted as the participants recruited into this study were all surgical patients and therefore not fully representative of the target population for this review. ...
... SQST demonstrated low/moderate sensitivity and high specificity when diagnosing lumbar lateral stenosis involving the L5 nerve root in the study of Lin et al. 30 . The population of patients used were all surgical and therefore not fully rep-resentative of the target population for this review, thus the applicability of these findings is poor. ...
Full-text available
Article
BACKGROUND: Sciatica is one of the most common reasons for seeking healthcare for musculoskeletal pain and can be a challenge to healthcare providers to diagnose and treat. In view of the variability of sciatica symptoms, a great range of patient reported outcome measures (PROMs) and performance-based measures (PBOs) have been developed for its assessment and management, with however, often poor or controversial results in their reliability and discriminative ability. Accurate diagnosis of sciatica is crucial to ensure appropriate intervention is given. However, to date there is no gold standard to diagnose sciatica. There has been no systematic review conducted to compare the diagnostic validity of assessment tools of sciatica. OBJECTIVE: To evaluate the diagnostic value of tools (PROMs and PBOs) used to assess patients presenting with sciatica METHODS: This review informed and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis-Protocols. PubMed, Science Direct, Cochrane Library, CINAHL, MEDLINE, EMBASE, key journals and grey literature searched rigorously to find diagnostic accuracy studies investigating patient with sciatica. Two independent reviewers conducted the search, extracted the data and assessed risk of bias for included studies using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. The overall quality of included studies evaluated using Grading of Recommendations, Assessment, Development and Evaluation guidelines. RESULTS: From 8347 studies, 11 studies were included. Nine studies out of the 11 were at risk of bias. Very low level evidence supports the use of dermatomal patterns and low level evidence supports the use of 7 tools (neurological examination, Βragard test, S-LANSS, ID Pain, PDQ, S-DN4, SQST) for diagnosing sciatica. Moderate level evidence supports a cluster of eight signs (age, duration of disease, paroxysmal pain, pain worse in leg than back, typical dermatomal distribution, worse on coughing/sneezing/straining, finger to floor distance and paresis), twenty items of patient history, self-reported items (pain below knee, which pain worst, numbness pins and needles), question «worsening of pain during sneezing coughing and straining» and Slump test for diagnosing sciatica. Also, moderate level evidence supports the use of the StEP tool for diagnosing lumbar radicular pain, demonstrating high sensitivity (92%) and specificity (97%) values. SLR showed moderate level evidence in one study and high level evidence in another study in diagnosing sciatica with sensitivity 63.46% and specificity 45.88%. CONCLUSIONS: Overall low-moderate level evidence supports the diagnostic utility of the tools examined in this review in diagnosing sciatica. The weak evidence base is largely due to methodological flaws and indirectness regarding applicability of the included studies. The most promising diagnostic tools include a cluster of 8 patient history/clinical examination signs, the StEP tool and the SLR test. From these results it is easily understood that history taking has a major role as assessment tool of sciatica in clinical practice. Low risk of bias and high level of evidence diagnostic utility studies are needed, in order for stronger recommendations to be made.
... Additionally, we found no spatial correlation of pain and soreness symptoms in the affection regions of FM (Fig. 1C), which is quite different from the concordant manifestations of pain and soreness in the post-exercise conditions [5,29]. In this sense, the investigations of non-exertional soreness in FM may provide a unique approach to probe the soreness nosography that previous DOMS research did not provide [1,3,29,30]. A comparison of non-exertional and exertional soreness is summarized in Table 2. ...
Full-text available
Preprint
Background: Muscle soreness occurs after exercise and also under morbid conditions, such as fibromyalgia (FM). However, how the morbid soreness manifests in FM and how it affects the disease remain unknown. Also, whether the non-exertional soreness in FM differs from exercise-induced soreness phenotypically is unclear. Methods: Fifty-one newly diagnosed FM patients from 166 consecutive cases of chronic musculoskeletal pain and 41 healthy controls were prospectively recruited. Musculoskeletal symptoms and metabolomics data were analyzed before the initiation of pharmacotherapy. Clinical manifestations and therapeutic responses were recorded with a follow-up of 4 weeks. Results: Soreness complaints were common in FM (92.2%). Soreness had clinical impacts different from pain, and affected stiffness and restless conditions. In terms of manifestations and metabolomic features, phenotypes diverged between cases with prominent soreness (FM-PS) and those without symptoms (FM-P). Conventional treatment did not ameliorate soreness severity despite its efficacy on pain. Moreover, despite the salient therapeutic efficacy on pain relief, current treatment did not improve the general disease severity in FM-PS versus FM-P. Metabolomics analyses suggested oxidative metabolism dysregulation in FM. Also, high malondialdehyde level indicated excessive oxidative stress in FM individuals (p=0.008). Contrary to exercise-induced soreness, lactate levels were significantly lower in FM individuals than controls, especially in FM-PS. Moreover, FM-PS cases exclusively featured increased malondialdehyde level (p=0.008) and its correlation with soreness intensity (r=0.337, p=0.086). Conclusion: Morbid soreness symptoms were prevalent in FM, with presentation distinct from exercise-induced soreness. Assessments of non-exertional soreness in FM may provide valid approaches for phenotype classification and therapeutic prediction.
... Because of high heterogeneity of reference standard use and populations between the studies, we opted not to perform a meta-analysis. Data were calculated using the EBM calculator [19], two-way contingency table analysis [20] and diagnostic posttest probability of disease calculator [21]. ...
Full-text available
Article
Purpose To update evidence of diagnostic potential for identification of lumbar spinal stenosis (LSS) based on demographic and patient history, clinical findings, and physical tests, and report posttest probabilities associated with test findings. Methods An electronic search of PubMed, CINAHL and Embase was conducted combining terms related to low back pain, stenosis and diagnostic accuracy. Prospective or retrospective studies investigating diagnostic accuracy of LSS using patient history, clinical findings and/or physical tests were included. The risk of bias and applicability were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS 2) tool. Diagnostic accuracy including sensitivities (SN), specificities (SP), likelihood ratios (+LR and −LR) and posttest probabilities (+PTP and −PTP) with 95% confidence intervals were summarized. Results Nine studies were included (pooled n = 36,228 participants) investigating 49 different index tests (30 demographic and patient history and 19 clinical findings/physical tests). Of the nine studies included, only two exhibited a low risk of bias and seven exhibited good applicability according to QUADAS 2. The demographic and patient history measures (self-reported history questionnaire, no pain when seated, numbness of perineal region) and the clinical findings/physical tests (two-stage treadmill test, symptoms after a March test and abnormal Romberg test) highly improved positive posttest probability by > 25% to diagnose LSS. Conclusion Outside of one study that was able to completely rule out LSS with no functional neurological changes none of the stand-alone findings were strong enough to rule in or rule out LSS. Graphic abstract These slides can be retrieved under Electronic Supplementary Material. Open image in new window
... However, in our experience, soreness (or sng) is a predominant sensory phenotype in patients with fibromyalgia and radiculopathy. In our series, soreness is not only one of the major complaints in lumbar stenosis-related low back pain, but also is one of the major reasons for surgical intervention because current treatment for soreness is unsatisfactory [42]. Therefore, soreness can be another major component in chronic pain disorders but is not yet valued. ...
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• Low back disorders are the most common cause of sciatica • Gluteal region disorders are the second most common cause of sciatica • Systemic illness such as autoimmune or vascular disease may contribute to sciatica • Patients may have more than one source of pain
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