Table 2. Operative treatments, complications and events accroding to stenosis level.
Surgical data, complications, and events according to stenosis level for the isolated spinal stenosis and degenerative spondylolisthesis cohorts.
| SPS | DS | ||||||
|---|---|---|---|---|---|---|---|
| Characteristic | 1 level (n=139) | 2 levels (n=154) | 3/3+ levels (n=95) | p-value | 1 level (n=224) | 2/2+ levels (n=104) | p-value |
| Specific procedures | 0.046 | 0.092 | |||||
| Decompression only | 121 (88%) | 134 (89%) | 86 (91%) | 9 (4%) | 7 (7%) | ||
| Non-instrumented fusion | 3 (2%) | 10 (7%) | 7 (7%) | 43 (19%) | 29 (28%) | ||
| Instrumented fusion | 13 (9%) | 7 (5%) | 2 (2%) | 172 (77%) | 68 (65%) | ||
| Multi-level fusion | 7 (5%) | 8 (5%) | 0 (0%) | 0.079 | 45 (20%) | 30 (29%) | 0.11 |
| Decompression Level | |||||||
| L2-L3 | 14 (10%) | 54 (35%) | 75 (79%) | <0.001 | 6 (3%) | 26 (25%) | <0.001 |
| L3-L4 | 55 (41%) | 124 (81%) | 91 (96%) | <0.001 | 61 (28%) | 83 (80%) | <0.001 |
| L4-L5 | 119 (89%) | 143 (93%) | 91 (96%) | 0.12 | 223 (100%) | 102 (98%) | 0.49 |
| L5-S1 | 39 (29%) | 62 (41%) | 48 (51%) | 0.004 | 53 (24%) | 42 (40%) | 0.004 |
| Levels decompresssed | <0.001 | <0.001 | |||||
| None | 5 (4%) | 1 (1%) | 0 (0%) | 0 (0%) | 0 (0%) | ||
| One | 68 (49%) | 14 (9%) | 3 (3%) | 131 (58%) | 12 (12%) | ||
| Two | 45 (32%) | 65 (42%) | 11 (12%) | 69 (31%) | 48 (46%) | ||
| Three+ | 21 (15%) | 74 (48%) | 81 (85%) | 24 (11%) | 44 (42%) | ||
| Operation time, minutes (SD) | 114.9 (71.7) | 128.8 (57.1) | 146.2 (63.9) | 0.001 | 208.4 (86.7) | 204.8 (78) | 0.72 |
| Blood loss, cc(SD) | 221 (444.1) | 338.1 (384.6) | 415.3 (381.3) | 0.001 | 532.3 (393.7) | 732.4 (605.6) | <0.001 |
| Blood Replacement | |||||||
| Intraoperative replacement | 12 (9%) | 19 (12%) | 6 (6%) | 0.25 | 74 (33%) | 42 (40%) | 0.26 |
| Post-operative transfusion | 7 (5%) | 7 (5%) | 5 (5%) | 0.97 | 43 (19%) | 24 (23%) | 0.53 |
| Length of hospital stay (SD) | 2.8 (2.5) | 5.7 (30) | 3.6 (3) | 0.40 | 6.4 (24.9) | 4.8 (3.2) | 0.52 |
| Intraoperative complications§ | |||||||
| Dural tear/spinal fluid leak | 8 (6%) | 19 (12%) | 9 (9%) | 0.15 | 19 (8%) | 14 (13%) | 0.23 |
| Vascular injury | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 1 (1%) | 0.69 | |
| Other | 1 (1%) | 1 (1%) | 1 (1%) | 0.94 | 7 (3%) | 2 (2%) | 0.80 |
| None | 130 (94%) | 133 (87%) | 85 (89%) | 0.17 | 199 (89%) | 88 (85%) | 0.37 |
| Postoperative complications/events¶ | |||||||
| Nerve root injury | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 1 (1%) | 0.70 | |
| Wound dehiscence | 0 (0%) | 0 (0%) | 0 (0%) | 1 (0%) | 0 (0%) | 0.70 | |
| Wound hematoma | 1 (1%) | 1 (1%) | 2 (2%) | 0.50 | 1 (0%) | 0 (0%) | 0.70 |
| Wound Infection | 4 (3%) | 2 (1%) | 1 (1%) | 0.49 | 10 (5%) | 1 (1%) | 0.19 |
| Other | 5 (4%) | 10 (7%) | 6 (6%) | 0.49 | 16 (7%) | 15 (14%) | 0.062 |
| None | 122 (88%) | 134 (88%) | 82 (86%) | 0.88 | 157 (71%) | 68 (65%) | 0.40 |
| Post-operative mortality (death within 6 weeks of surgery) | 1‡ (0.7%) | 0 (0%) | 0 (0%) | 0.41 | 1 (0.4%) | 0 (0%) | 0.69 |
| Post-operative mortality (death within 3 months of surgery) | 1‡ (0.7%) | 0 (0%) | 0 (0%) | 0.41 | 1 (0.4%) | 1 (1%) | 0.84 |
| Additional surgeries (1-year rate)∥ | 6 (4%) | 11 (7%) | 3 (3%) | 0.316 | 16 (7%) | 5 (5%) | 0.41 |
| Additional surgeries (2-year rate)∥ | 10 (7%) | 15 (10%) | 5 (5%) | 0.402 | 24 (11%) | 18 (17%) | 0.127 |
| Recurrent stenosis / progressive listhesis | 4 (2.8%) | 4 (2.6%) | 2(2.1%) | 4 (1.8%) | 7 (6.8%) | ||
| Pseudarthrosis / fusion exploration | 0 (0%) | 0 (0%) | 0 (0%) | 2 (0.9%) | 1 (1%) | ||
| Complication or Other | 5 (3.5%) | 9 (5.9%) | 0 (0%) | 17 (7.6%) | 5 (4.9%) | ||
| New condition | 1 (0.7%) | 3 (2%) | 2(2.1%) | 2 (0.9%) | 3 (2.9%) | ||
§
None of the following were reported: aspiration, nerve root injury, operation at wrong level.
¶
Any reported complications up to 8 weeks post operation. None of the following were reported: bone graft complication, CSF leak, paralysis, cauda equina injury, pseudarthrosis.
∥
One- and two year post-surgical re-operation rates are Kaplan Meier estimates and p-values are based on log-rank test.