Table 2.
Univariate Analysis of Relative Risk for unintended durotomy during Spine Surgery
| Risk Factors | Dural Tear 161 (10%) | No Dural Tear 1430 (90%) | RR of Dural Tear | 95% CI | p-value |
|---|---|---|---|---|---|
| Length of Follow-Up1 (months), mean (sd) | 22.4 (19.0) | 16.5 (16.1) | |||
| Age (yr), mean (sd) | 54.6 (14.6) | 49.0 (16.0) | < 0.001* | ||
| 18 - 39 | 26 (6%) | 405 (94%) | 1.00 | - | 0.002* |
| 40 - 64 | 94 (11%) | 765 (89%) | 1.81 | 1.19 – 2.76 | |
| ≥65 | 41 (14%) | 260 (86%) | 2.26 | 1.41 – 3.61 | |
| Gender | |||||
| Male | 82 (9%) | 832 (91%) | 1.00 | - | 0.08 |
| Female | 79 (12%) | 598 (88%) | 1.30 | 0.97 – 1.74 | |
| Smoking | |||||
| No | 119 (11%) | 984 (89%) | 1.00 | - | 0.18 |
| Yes | 42 (9%) | 446 (91%) | 0.80 | 0.57 – 1.12 | |
| Alcohol | |||||
| No | 93 (10%) | 830 (90%) | 1.00 | - | 0.95 |
| Yes | 68 (10%) | 600 (90%) | 1.01 | 0.75 – 1.36 | |
| Drug Use | |||||
| No | 149 (10%) | 1275 (90%) | 1.00 | - | 0.18 |
| Yes | 12 (7%) | 155 (93%) | 0.69 | 0.39 – 1.21 | |
| Diabetes | |||||
| No | 134 (9%) | 1278 (91%) | 1.00 | - | 0.02* |
| Yes | 27 (15%) | 152 (85%) | 1.59 | 1.08 – 2.33 | |
| BMI | 28.5 (7.2) | 27.6 (6.4) | 0.13 | ||
| Underweight (< 18.5) | 10 (7%) | 130 (93%) | 1.00 | - | 0.47 |
| Normal (18.5 - < 25) | 47 (9%) | 463 (91%) | |||
| Overweight (25 - < 30) | 54 (11%) | 449 (89%) | 1.22 | 0.86 – 1.74 | |
| Obese (30 - < 35) | 28 (10%) | 240 (90%) | 1.19 | 0.78 – 1.83 | |
| ≥ 35 | 22 (13%) | 148 (87%) | 1.48 | 0.93 – 2.34 | |
| Charlson Comorbidity Adjusted for Diabetes, mean (sd) | 1.4 (1.7) | 1.2 (1.6) | 0.16 | ||
| 0 | 63 (9%) | 618 (91%) | 1.00 | - | 0.35 |
| 1 | 34 (10%) | 315 (90%) | 1.05 | 0.71 – 1.57 | |
| 2 | 25 (13%) | 169 (87%) | 1.39 | 0.90 – 2.15 | |
| 3 | 13 (10%) | 122 (90%) | 1.04 | 0.59 – 1.84 | |
| ≥ 4 | 22 (14%) | 138 (86%) | 1.49 | 0.94 – 2.34 | |
| Diagnosis Group | |||||
| Degenerative | 131 (13%) | 860 (87%) | 1.00 | - | < 0.001 |
| Trauma | 14 (4%) | 358 (96%) | 0.28 | 0.17 – 0.49 | |
| Neoplasm | 8 (7%) | 109 (93%) | 0.52 | 0.26 – 1.03 | |
| Infection | 6 (10%) | 53 (90%) | 1.30 | 0.60 – 2.82 | |
| Other | 2 (4%) | 50 (96%) | 0.29 | 0.07 – 1.14 | |
| Diagnosis Level | |||||
| Lumbosacral | 124 (16%) | 643 (84%) | 1.00 | - | < 0.001 |
| Cervical | 26 (4%) | 556 (96%) | 0.27 | 0.18 – 0.42 | |
| Thoracic | 11 (5%) | 229 (95%) | 0.28 | 0.16 – 0.52 | |
| Revision | |||||
| No | 99 (8%) | 1207 (92%) | 1.00 | - | < 0.001 |
| Yes | 62 (22%) | 223 (78%) | 2.87 | 2.15 – 3.84 | |
| Surgical Approach | |||||
| Posterior | 90 (10%) | 844 (90%) | 1.00 | - | < 0.001 |
| Anterior | 7 (2%) | 285 (98%) | 0.25 | 0.12 – 0.53 | |
| Combined | 64 (18%) | 301 (82%) | 1.82 | 1.35 – 2.45 | |
| Invasiveness Index, mean (sd) | 11.3 (9.9) | 8.2 (7.1) | < 0.001 | ||
| 1 - 5 | 65 (9%) | 668 (91%) | 1.00 | - | < 0.001 |
| 6 - 10 | 27 (7%) | 383 (93%) | 0.74 | 0.48 – 1.14 | |
| 11 – 15 | 28 (12%) | 212 (88%) | 1.32 | 0.87 – 2.00 | |
| 16 - 20 | 13 (14%) | 79 (86%) | 1.59 | 0.92 – 2.77 | |
| 21 - 25 | 9 (19%) | 38 (81%) | 2.16 | 1.15 – 4.06 | |
| > 25 | 19 (28%) | 50 (72%) | 3.11 | 1.98 – 4.86 | |
RR=Relative Risk, CI = confidence intervals