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| Research | Modality | Participants | Segments measured | Level of measurement | Method | Fatty infiltration | Association with LBP |
|
| Fortin et al. [24] | MRI | 33 patients diagnosed with posterolateral disc herniation at L4-L5 | | The center of each intervertebral disc, the center of S1 vertebral body, perpendicular to the muscle mass | The ratio of lean mass CSA to total CSA as an indicator of muscle composition (or fatty infiltration) | Multifidus affected side | Multifidus nonaffected side | Greater fat infiltration on the side and at spinal levels adjacent to the disc herniation. Muscle asymmetry was not correlated with symptom duration |
| L3-L4 | 0.58 ± 0.21 | 0.61 ± 0.17 |
| L4-L5 | 0.55 ± 0.16 | 0.57 ± 0.14 |
| L5-S1 | 0.51 ± 0.11 | 0.53 ± 0.11 |
| S1 | 0.46 ± 0.12 | 0.49 ± 0.13 |
| | Erector spine affected side | Erector spine nonaffected side |
| L3-L4 | 0.58 ± 0.17 | 0.61 ± 0.14 |
| L4-L5 | 0.47 ± 0.17 | 0.52 ± 0.12 |
| L5-S1 | 0.30 ± 0.15 | 0.36 ± 0.15 |
| S1 | 0.29 ± 0.26 | 0.32 ± 0.17 |
| | Signal intensity as an indicator for fatty infiltration | Multifidus affected side | Multifidus nonaffected side |
| L3-L4 | 1959.1 ± 1606.3 | 1972.6 ± 1610.7 |
| L4-L5 | 2015.3 ± 1811.4 | 2243.2 ± 1766.0 |
| L5-S1 | 2625.3 ± 2109.2 | 2476.3 ± 1932. |
| S1 | 3159.4 ± 2001.5 | 53029.2 ± 1837.5 |
| | Erector spine affected side | Erector spine nonaffected |
| L3-L4 | 1988.0 ± 1593.1 | 1882.0 ± 1468.3 |
| L4-L5 | 2520.6 ± 2092.6 | 2338.7 ± 1821.1 |
| L5-S1 | 2876.9 ± 2320.6 | 2804.5 ± 2200.1 |
| S1 | 3688.4 ± 2137.2 | 3323.7 ± 1795.4 |
|
| Hebert et al. [34] | MRI | 401 participants. 40-year-old adults randomly sampled from a Danish population and followed up at 45 and 49 years of age | L4
L5 | | Using signal intensity to separate muscle from fat. Presented as % of the fat CSA from the total muscle CSA | Out of the four results (level L4, L5: left and right side), only the highest percentage of fat is presented
Age 40: 28.8 ± 12.7%
Age 45: 28.7 ± 11.9%
Age 49: 31.6 ± 13.0% | The relationship between multifidus fat infiltration and LBP/leg pain is inconsistent and may be modified by age |
|
| D’hooge et al. [25] | MRI | 13 individuals with recurrent nonspecific LBP, and 13 asymptomatic individuals | L3
L4
L4 | Superior endplate
Superior endplate
Inferior end plate
Axial images | Muscle-fat-index | Multifidus:
LBP: 18.4 ± 6.4
Control: 14.0 ± 2.6
Erector spine:
LBP: 23.9 ± 6.1
Control: 20.7 ± 2.5 | The increase in fatty infiltration in lean lumbar muscle tissue, in the absence of alterations in muscle size or macroscopic fat deposition after resolution of LBP. It is hypothesized that decreased muscle quality may contribute to the recurrence of LBP |
|
| Niemeläinen et al. [35] | MRI | 126 asymptomatic men | L3-L4
L4-L5
L5-S1 | Not described in the manuscript | The ratio of functional CSA to total CSA as an indicator of muscle composition (or fatty infiltration) | Multifidus:
L3-L4; Rt: 82, Lt: 83
L4-L5; Rt: 76, Lt: 77
L5-S1; Rt: 72, Lt: 73
Erector spine:
L3-L4; Rt: 84, Lt: 85
L4-L5; Rt: 77, Lt: 79
L5-S1; Rt: 73, Lt: 76 | The amount of intramuscular fat significantly increased caudally for both muscles.
Paraspinal muscle asymmetry, >10%, was commonly found in men without a history of LBP |
|
| Mengiardi et al. [13] | MR spectroscopy | 25 patients with chronic LBP and in 25 matched asymptomatic volunteers | L4-5 level | | Mean percentage fat content of the muscle | Multifidus:
Chronic LBP: 23.6%
Control: 14.5%
Erector spine:
Chronic LBP: 29.3%
Control: 26.0% | Significantly higher fat content in the multifidus muscle in patients with chronic LBP than in asymptomatic volunteers |
|
| Chan et al. [27] | US, in prone position | 12 asymptomatic men; 12 men with LBP | L4
L4 | Vertebral lamina | Fat CSA (cm2) | Multifidus controls:
Lt; 0.56 ± 0.10;
Rt; 0.61 ± 0.09
Multifidus LBP:
Lt; 1.08 ± 0.23;
Rt; 1.13 ± 0.23 | Fat area within the multifidus was larger in chronic LBP patients |
|
