Comparison of histological characteristics of the diaphragm in the active and sham stimulation groups
| Characteristic | Stimulation group | p-value | |
| Active | Sham | ||
| Type-1 fibres | |||
| Minimum diameter µm | 53.7 (51.0–60.3) | 50.9 (46.9–59.0) | ns |
| Proportion % | 54.5 (41.5–61.5) | 57.3 (44.5–67.2) | ns |
| Proportion of atrophic fibres# % | 55.6 (46.5–60.1) | 64.8 (44.1–75.4) | ns |
| Proportion of enclosed fibres¶ % | 5.1 (3.6–11.9) | 6.1 (2.5–9.0) | ns |
| Type-2 fibres | |||
| Minimum diameter μm | 45.0 (38.6–55.4) | 40.8 (33.6–53.7) | ns |
| Proportion of atrophic fibres# % | 52.0 (37.6–69.3) | 67.4 (41.9–76.3) | ns |
| Proportion of enclosed fibres¶ % | 1.3 (0.5–2.5) | 0.7 (0.3–2.1) | ns |
Data are presented as median (interquartile range). ns: not significant. #: atrophic fibres are those with a diameter of two standard deviations below the mean diameter measured in normal patients [10]; ¶: enclosed muscle fibres are those surrounded on all sides by fibres of the same type [17].