Characteristics of the 4 study groups or the number and percentage of patients with the condition*
| Characteristics | Ghent Independent of DE (n = 73) | Ghent Dependent on DE (n = 14) | Not Fulfilling Ghent (n = 18) | Control (n = 101) | P Value |
|---|---|---|---|---|---|
| Age (mean ± SD) | 39.4 (12.2) | 40.6 (17.1) | 36.1 (13.4) | 39.6 (12.9) | .74 |
| Females (No.) (%) | 45 (61.6) | 11 (78.6) | 11 (61.6) | 64 (63.4) | .68 |
| DSR L3 (mean ± SD) | 0.50b,c (0.11), n = 69 | 0.53c (0.06) | 0.43a (0.08), n = 14 | 0.45a,b (0.07) | <.001 |
| DSR L4 (mean ± SD | 0.50b (0.12), n = 72 | 0.51b (0.07) | 0.41a (0.06) | 0.43a (0.07) | <.001 |
| DSR L5 (mean ± SD) | 0.57b (0.18), n = 68 | 0.65b (0.20) | 0.39a (0.09) | 0.42a (0.08) | <.001 |
| DSR S1 (mean ± SD) | 0.94b (0.69), n = 61 | 1.02b (0.77), n = 13 | 0.40a (0.12), n = 12 | 0.41a (0.13), n = 96 | <.001 |
| DSD sacrum > DSD L4 | 38 (55.1%), n = 69 | 4 (28.6%) | 1 (5.6%) | 5 (5.0%) | <.001 |
| Herniation of nerve root sleeves | |||||
| Present in ≥1 level (No.) (%) | 53 (72.6%) | 10 (71.4%) | 2 (11.1%) | 1 (1%) | <.001 |
| Present in level L5 | 9 (12.3%) | 0 (0%) | 0 (0%) | 0 (0%) | <.001 |
| Present in level S1 | 35 (47.9%) | 8 (57.1%) | 2 (11.1%) | 0 (0%) | <.001 |
| Present in level S2 | 48 (65.8%) | 8 (57.1%) | 1 (5.6%) | 1 (1%) | <.001 |
| Present in level S3 | 30 (41.1%) | 5 (35.7%) | 0 (0%) | 0 (0%) | <.001 |
| Present in level S4 | 8 (11%) | 1 (7.1%) | 0 (0%) | 0 (0%) | <.004 |
| Odds ratio, ≥1 herniation of the nerve root sleeve | 265 (34–2029) | 250 (25–2458) | 12.5 (1–145) | ref | <.001 |
| Anterior meningocele | 27 (37%) | 2 (14%) | 0 | 0 | <.001 |
| Scalloping L1-S1 ≥1 level | 44 (61.1 %), n = 72 | 8 (42.9%) | 1 (5.6%) | 4 (4%), n = 100 | <.001 |
| Perineural cysts | 11 (15.1 %) | 1 (7.1%) | 1 (5.6%) | 8 (7.9%) | .387 |
| Disk herniation beneath T12 | 5 (7%), n = 69 | 1 (7%) | 2 (11%) | 6 (6%) | .890 |
| Caudal end of dural sac | |||||
| L5, L5/S1, S1 | 10 (14.5%) | 0 (0%) | 9 (50%) | 22 (21.8%) | <.001 |
| S2 | 26 (37.7%) | 9 (64.3%) | 8 (44.4%) | 68 (67.3%) | <.001 |
| S3, S4, S5 | 33 (47.8%), n = 69 | 5 (35.7%) | 1 (5.6%) | 11 (10.9%) | <.001 |
Note:—DE, dural ectasia; DSR, dural sac ratio; DSD, dural sac diameter.
* Study groups not containing similar letters (a, b, c, or d) for means were statistically different at the 5% level. Where n is specified in a cell, there were some observations missing and n is the actual number of observations. Missing values are due to incomplete anatomic coverage with CT, extreme scoliosis at MR, or the dural sac ending above the missed level.