Lumbar spinal stenosis associated with progression of locomotive syndrome and lower extremity muscle weakness

Figures & data

Table 1 LSS diagnostic support tool

	Question	LSS score
Q1	Numbness and/or pain in the thigh(s) down to the calf (calves) and shin(s)	N.A.
Q2	Difficulty bending forward because of numbness and/or pain	−1
Q3	Difficulty putting on socks because of numbness and/or pain	−1
Q4	Difficulty lying on the back with hip and knee extension because of numbness and/or pain	N.A.
Q5	Difficulty sitting with knee extension of the involved leg	N.A.
Q6	Numbness and/or pain increase in intensity after walking for a while, but are relieved by taking a rest	5
Q7	Standing for a while brings numbness and/or pain in the thigh(s) down to the calf or calves and shin(s)	5
Q8	Numbness and/or pain are reduced by bending forward	1
Q9	Numbness is present, but pain is absent	1
Q10	Numbness and/or pain is present in both feet	2
Q11	Numbness is present in soles of both feet	3
Q12	Numbness arises around the buttocks	3
Q13	Feel the urge to urinate when walking	N.A.
Q14	I am ≤40 years old	N.A.
Q15	I am ≥60 years old	4

Notes: Adapted from Aizawa T, Tanaka Y, Yokoyama T, et al. New diagnostic support tool for patients with leg symptoms caused by lumbar spinal stenosis and lumbar intervertebral disc herniation: a self-administered, self-reported history questionnaire. J Orthop Sci. 2016;21(5):579–585.¹⁰ Copyright 2016, with permission from Elsevier.

Abbreviations: LSS, lumbar spinal stenosis; N.A., not applicable; Q, question number.

Figure 1 The muscle strength of the lower extremities, including hip flexors (A) and knee extensors (B), was measured with a handheld dynamometer (Commander™ PowerTrack II™ Handheld Dynamometer; Nihon Medix Co., Ltd., Matsudo, Japan). The mean strength of the two lower extremities was calculated and all calculations were performed twice. Isometric back extensor strength in the prone position was measured using a strain-gauge dynamometer (DPU-1000N Digital Force Gauge; Imada, Toyohashi, Japan) (C). The subject was aligned on the board with a strain-gauge dynamometer attached to the subject’s back. After the strain-gauge was placed (at the mid-portion of back at the inferior part of scapula), we asked the subject to lift their upper trunk as high as possible. The strain-gauge recorded the maximum strength. Measurements were performed three times and the values from the trial that produced the greatest force were selected.

Table 2 Participant characteristics

	LSS+	LSS−	P-value
Number of participants	23	90
LSS score	17.0 [14.0, 18.5]	5.3 [4.0, 5.0]	<0.001*
Male:female	15:8	43:47	0.164^#
Average age, years	75.9 (9.4)	73.5 (7.8)	0.226**
Height, cm	158.2 (7.3)	155.4 (8.0)	0.134**
Weight, kg	59.6 (10.4)	55.1 (10.1)	0.060**

Notes: Mean (standard deviation), Median [lower, upper quartiles]. Cut-off score for LSS diagnosis: LSS+, ≥13; LSS−, <13. *Mann–Whitney U-test; ^#Chi-square test; **Unpaired t-test.

Abbreviation: LSS, lumbar spinal stenosis.

Table 3 Locomotive syndrome risk test

	LSS+ (n=23)	LSS− (n=90)	P-value
Stand-up test			0.003^##
Bilateral legs 40 cm	0	0
30 cm (%)	4 (17)	0
20 cm (%)	2 (9)	10 (12)
10 cm (%)	10 (43)	26 (29)
One leg 40 cm (%)	7 (31)	39 (43)
30 cm (%)	0	12 (13)
20 cm (%)	0	1 (1)
10 cm (%)	0	2 (2)
Two-step test	1.21 [1.06, 1.38]	1.36 [1.25, 1.49]	0.002*
GLFS-25
Total score	21.7 [13.5, 28.5]	5.0 [2.0, 7.0]	<0.0001*
Pain-related score	5.9 [3.5, 8.5]	1.9 [0.0, 3.0]	<0.0001*
ADL-related score	10.5 [3.5, 15.5]	1.8 [0.0, 3.0]	<0.0001*
Social-functions-related score	3.1 [1.0, 4.0]	0.7 [0.0, 1.0]	<0.0001*
Mental-health-related score	2.2 [1.0, 4.0]	0.6 [0.0, 1.0]	<0.0001*

Notes: Median [lower, upper quartiles]. ^##Fisher’s exact test; *Mann–Whitney U-test; Cut-off score for LSS diagnosis: LSS+, ≥13; LSS−, <13.

Abbreviations: ADL, activities of daily living; LSS, lumbar spinal stenosis; GLFS-25, 25-question Geriatric Locomotive Function Scale.

Table 4 Risk levels for locomotive syndrome from the three tests

	LSS+ (n=23)	LSS− (n=90)	P-value^##
Stand-up test			0.0004
Stage 0 (%)	7 (30)	54 (60)
Stage 1 (%)	12 (52)	36 (40)
Stage 2 (%)	4 (18)	0 (0)
Two-step test			0.0007
Stage 0 (%)	9 (39)	66 (73)
Stage 1 (%)	6 (26)	11 (12)
Stage 2 (%)	8 (35)	13 (15)
GLFS-25			<0.0001
Stage 0 (%)	2 (9)	60 (67)
Stage 1 (%)	9 (39)	24 (27)
Stage 2 (%)	12 (52)	6 (6)

Notes: ^##Fisher’s exact test. Cut-off score for LSS diagnosis: LSS+, ≥13; LSS−, <13.

Abbreviations: LSS, lumbar spinal stenosis; GLFS-25, 25-question Geriatric Locomotive Function Scale.

Table 5 Muscle strength

	LSS+ (n=23)	LSS− (n=90)	P-value**
Grip strength, kg	27.9 (8.8)	28.2 (8.6)	0.905
Back extensor strength, kg	16.1 (10.0)	19.9 (10.5)	0.128
Hip flexor strength, kg	10.6 (4.7)	13.4 (4.9)	0.014
Knee extensor strength, kg	11.5 (3.6)	13.6 (3.7)	0.017

Notes: Mean (standard deviation). **Unpaired t-test; Cut-off score for LSS diagnosis: LSS+, ≥13; LSS−, <13.

Abbreviation: LSS, lumbar spinal stenosis.

Aizawa T, Tanaka Y, Yokoyama T, et al. New diagnostic support tool for patients with leg symptoms caused by lumbar spinal stenosis and lumbar intervertebral disc herniation: a self-administered, self-reported history questionnaire. J Orthop Sci. 2016;21(5):579–585. doi:10.1016/j.jos.2016.07.01227527658

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