Table 2.
Operative treatments, complications and events.
| Randomized Cohort (n=166*) |
Observational Cohort (n=245) |
p-value | |
|---|---|---|---|
| Procedure | 0.53 | ||
| Decompression only | 142 (88%) | 213 (88%) | |
| Non-instrumented fusion | 7 ( 4%) | 15 ( 6%) | |
| Instrumented fusion | 12 ( 7%) | 13 ( 5%) | |
| Multi-level fusion | 5 (3%) | 11 (4%) 0.62 | |
| LaminectomyLevel | |||
| L2-L3 | 57 (35%) | 90 (37%) | 0.74 |
| L3-L4 | 123 (76%) | 159 (66%) | 0.043 |
| L4-L5 | 149 (92%) | 224 (93%) | 0.86 |
| L5-S1 | 62 (38%) | 91 (38%) | 1 |
| Levels decompresssed | 0.81 | ||
| 0 | 4 ( 2%) | 4 ( 2%) | - |
| 1 | 35 (21%) | 58 (24%) | - |
| 2 | 50 (30%) | 78 (32%) | - |
| 3+ | 77 (46%) | 105 (43%) | - |
| Operation time | 129 (64.1) | 128.6 (67) | 0.96 |
| Blood loss | 333.2 (515.3) | 296.9 (310.4) | 0.38 |
| Blood Replacement | |||
| Intraoperative replacement | 15 (9%) | 24 (10%) | 1 |
| Post-operative transfusion | 7 (4%) | 13 (5%) | 0.82 |
| Lenth of stay | 3.5 (2.6) | 3 (2.2) | 0.023 |
| Post-operative mortality (death within 6 weeks of surgery) |
0 (0%) | 1 (0.4%)‡ | 0.84 |
| Post-operative mortality (death within 3 months of surgery) |
0 (0%) | 1 (0.4%)‡ | 0.84 |
| Intraoperative complications§ | |||
| Dural tear/ spinal fluid leak | 15 (9%) | 23 (9%) | 0.95 |
| Other | 1 (1%) | 2 (1%) | 0.73 |
| None | 149 (90%) | 219 (90%) | 0.99 |
| Postoperative complications/events¶ | |||
| Wound hematoma | 3 (2%) | 1 (0%) | 0.35 |
| Wound infection | 4 (2%) | 5 (2%) | 0.95 |
| Other | 10 (6%) | 14 (6%) | 0.97 |
| None | 141 (87%) | 213 (87%) | 0.94 |
| Additional surgeries (1-year rate)∥ | 7 (4%) | 15 (6%) | 0.41 |
| Additional surgeries (2-year rate)∥ | 11 (7%) | 21 (8%) | 0.48 |
| Additional surgeries (3-year rate)∥ | 17 (10%) | 29 (12%) | 0.64 |
| Additional surgeries (4-year rate)∥ | 22 (13%) | 32 (13%) | 0.94 |
| Recurrent stenosis/progressive spondylolisthesis | 15 (9%) | 9 (4%) | |
| Pseudoarthrosis/fusion exploration | 0 (0%) | 0 (0%) | |
| Complication or Other | 6 (4%) | 12 (5%) | |
| New condition | 1 (NE) | 7 (3%) |
171 RCT and 252 OBS patients had surgery, surgical information was available for 166 RCT patients and 245 observational patients. Specific procedure information was available on 161 RCT and 241 OBS patients.
Patient died 9 days after surgery of a myocardial infarction. The death was juded probably related to treatment by the DHMC review and not related to treatment by the external review.
None of the following were reported: aspiration, nerve root injury, operation at wrong level, vascular injury.
Any reported complications up to 8 weeks post operation. None of the following were reported: bone graft complication, CSF leak, nerve root injury, paralysis, cauda equina injury, wound dehiscence, pseudarthrosis.
One-, two-, three- and four-year post-surgical re-operation rates are Kaplan Meier estimates and p-values are based on the log-rank test. Numbers and percentages are based on the first additional surgery if more than one additional surgery. Surgeries include any additional spine surgery not just re-operation at the same level.