The demographic characteristics of the current study patients according to the groups are presented in Table 1. In this analysis, age and BMI were put in the model as covariate variables. In the covariate variable, it was aimed to control the effects of age and BMI values on dependent variables.
Table 1 Comparison of the age, gender, BMI, pain duration, and pain intensity of the patients according to the groups
1Kruskal Wallis, 2Mann Whitney U, 3 Pearson Chi Square, VAS (Vısual Analog Scale), LBP: Low back pain, BMI: body mass index, m:month, a-a: There is no difference between groups with the same letter, a-b-ab: There is a difference between groups with different letters.
Investigation of CSA and TCSA by groups
CSA mean value (Table 2) differed only in the right L.MF and healthy group (p=0.011). The average CSA value in Group 1 was lower than in Group 2 and Group 3. There was no difference between the groups in TCSA in other muscle groups. There was no difference between Group 2 and Group 3.
Table 2 Descriptive statistics by groups (mm2)
|
Parameter
|
Group 1
|
Group 2
|
Group 3
|
CSA
|
Right musculus multifidus (mm2 )
|
934.36 ± 264.05a
|
968.87 ± 301.57b
|
1036.74 ± 291.75b
|
Left musculus multifidus(mm2 )
|
947.18 ± 265.14
|
947.13 ± 295.38
|
1018.41 ± 287.11
|
Right erector spinae (mm2 )
|
1669.24 ± 456.47
|
1588.69 ± 581.23
|
1799.63 ± 492.89
|
Left erector spinae (mm2 )
|
1709.66 ± 466.18
|
1598.44 ± 563.83
|
1809.17 ± 521.59
|
TCSA
|
Right musculus multifidus, erector spinae (mm2 )
|
2603.6 ± 458.23
|
2557.56 ± 663.64
|
2836.38 ± 564.46
|
Left musculus multifidus, erector spinae (mm2 )
|
2656.83 ± 477.35
|
2545.58 ± 636.81
|
2827.58 ± 574.53
|
b-b: no difference between groups with the same letter, a-b-: There is a difference between groups with different letters, CSA:Cross-sectional area, TCSA: Total cross-sectional area
The mean CSA and TCSA values differed in all muscle groups according to gender (p <0.001) (Table 3). In all three groups, the CSA and TCSA values were higher in males than females.
No relationship was determined between age and the CSA and TCSA in the healthy group (Table 3). A moderate positive correlation was found in the mechanical low back pain group (p<0.05), and a weak positive correlation was found in the lumbar hernia group (p <0.05).
According to segments (L3-L4, L4-L5, L5-S1) (Table 3), cross-sectional areas differed statistically in all groups (p<0.001). In all groups, the largest L.MF CSA was found in L5-S1, and the smallest in the L3-L4 segment, while the largest L.ES CSA was found in L3-4 and the smallest in the L5-S1 segment. In the side comparison (asymmetry) (Table 2), CSA did not differ between the right / left sides among all groups.
A positive weak, medium level relationship was determined between BMI and CSA and TCSA in Group 1(p<0.05), a positive weak, moderate relationship in Group 2 (p <0.05) and a positive moderate relationship in Group 3 (p<0.05) (Table 3).
In terms of pain, no relationship was found between Group 2 and Group 3 between the duration of low back pain and the CSA and TCSA of the muscles. A negative weak relationship was found between resting pain intensity and CSA and TCSA in Group 2 (p<0.05). While there was no correlation between activity pain intensity and CSA of the muscles, a weak negative correlation was found with TCSA (p <0.05). In Group 3, no significant relationship was found between resting and activity pain intensity and muscle CSA and TCSA.
Table 3 Comparisons of the CSA and TCSA of the groups according to gender, segment, age, BMI
R:Right, L: Left, LMF: lumbar musculus multifidus LES: Lumbar Erector Spinae, BMI: Body Mass Index, CSA:Cross-sectional area, TCSA: Total cross-sectional area, η2: Partial Eta Square
Analysis of fat infiltration according to groups
When the fat infiltrations were examined (Table 4), the right L.MF, left L.MF, and left L.ES differed between the groups (p=0.011, p=0.001, p=0.027, respectively). Right L.ES did not differ between groups (p=0.0192). While the rate of fat infiltration <10% was higher in Group 1 than in Group 2 and Group 3, it was determined that 10-50% and >50% fat infiltration was higher in Group 2 and Group 3 than in Group 1.
Table 4 Examination of fat infiltrations in groups (Simplified 3 degree system)
|
Group 1
|
Group 2
|
Group 3
|
Total
|
P*
|
Fat infiltration R.L.MF
|
|
|
|
|
|
<10%
|
38 (42.2)a
|
17 (18.9)b
|
27 (30)ab
|
82 (30.4)
|
0.011
|
10-50%
|
52 (57.8)a
|
71 (78.9)b
|
62 (68.9)ab
|
185 (68.5)
|
>50%
|
0 (0)
|
2 (2.2)
|
1 (1.1)
|
3 (1.1)
|
Fat infiltration L.L.MF
|
|
|
|
|
|
<10%
|
39 (43.3)a
|
15 (16.7)b
|
31 (34.4)a
|
85 (31.5)
|
0.001
|
10-50%
|
51 (56.7)a
|
72 (80)b
|
58 (64.4)ab
|
181 (67)
|
>50%
|
0 (0)
|
3 (3.3)
|
1 (1.1)
|
4 (1.5)
|
Fat infiltration R.L.ES
|
|
|
|
|
|
<10%
|
33 (36.7)
|
21 (23.3)
|
30 (33.3)
|
84 (31.1)
|
0.192
|
10-50%
|
56 (62.2)
|
64 (71.1)
|
57 (63.3)
|
177 (65.6)
|
>50%
|
1 (1.1)
|
5 (5.6)
|
3 (3.3)
|
9 (3.3)
|
Fat infiltration L.L.ES
|
|
|
|
|
|
<10%
|
34 (37.8)a
|
22 (24.4)b
|
31 (34.4)ab
|
87 (32.2)
|
0.027
|
10-50%
|
55 (61.1)
|
61 (67.8)
|
58 (64.4)
|
174 (64.4)
|
>50%
|
1 (1.1)
|
7 (7.8)
|
1 (1.1)
|
9 (3.3)
|
* Chi-square test, R.L.MF: Right Lumbar Musculus Multifidus, L.L.MF: Left L.MF, R.L.ES: Right Lumbar Erector Spinae, L.L.ES: Left L.ES, a-a: There is no difference between groups with the same letter, a-b-ab: Different letters There is a difference between groups that have
Fat infiltration by gender differed between groups (right and left L.MF, right and left L.ES) (p=0.001, p=0.001, p=0.009, p=0.002, respectively). In all groups, a higher rate of fat infiltration was observed in females than in males.
In the relationship between age and fat infiltration, only a weak negative correlation was found between left L.MF (r=0.123, p=0.043). There was no significant relationship between age and other muscles in respect of fat infiltration. There was no relationship between BMI and fat infiltration values of the muscles.
Fat infiltration differed according to segments (L3-L4, L4-L5, L5-S1) (p<0.001). In the right L.MF, the lowest fat infiltration was at L3-L4, and the highest at L5-S1, in the left L.MF the lowest was at L3-L4 and the highest at L4-L5 / L5-S1. In the right L.ES, the lowest was at L3-L4 and the highest fat infiltration was at L4-L5 / L5-S1, and in the left L.ES, the lowest was at L3-L4 and the highest at L5-S1.
In terms of pain duration and severity, in Group 3, a weak positive correlation was found between the duration of pain and only left L.ES fat infiltration (p<0.05).