Table 2.
Operative treatments, complications and events.
| SpS | One year or less (n=252) |
More than one year (n=159) |
p-value | 6 months or less (n=168) |
7 to 12 months (n=84) |
More than one year (n=159) |
p-value |
|---|---|---|---|---|---|---|---|
| Specific procedures† | 0.11 | 0.13 | |||||
| Decompression only | 224 (90%) | 131 (85%) | 152 (92%) | 72 (87%) | 131 (85%) | ||
| Non-instrumented fusion | 9 (4%) | 13 (8%) | 6 (4%) | 3 (4%) | 13 (8%) | ||
| Instrumented fusion | 15 (6%) | 10 (6%) | 7 (4%) | 8 (10%) | 10 (6%) | ||
| Multi-level fusion | 9 (4%) | 7 (4%) | 0.87 | 6 (4%) | 3 (4%) | 7 (4%) | 0.91 |
| Decompression level | |||||||
| L2–L3 | 86 (35%) | 61 (39%) | 0.44 | 60 (37%) | 26 (31%) | 61 (39%) | 0.49 |
| L3–L4 | 167 (68%) | 115 (74%) | 0.23 | 112 (68%) | 55 (66%) | 115 (74%) | 0.41 |
| L4–L5 | 222 (90%) | 151 (97%) | 0.02 | 147 (90%) | 75 (90%) | 151 (97%) | 0.04 |
| L5–S1 | 91 (37%) | 62 (40%) | 0.63 | 57 (35%) | 34 (41%) | 62 (40%) | 0.54 |
| Levels decompressed | 0.31 | 0.64 | |||||
| None | 5 (2%) | 3 (2%) | 4 (2%) | 1 (1%) | 3 (2%) | ||
| 1 | 64 (25%) | 29 (18%) | 41 (24%) | 23 (27%) | 29 (18%) | ||
| 2 | 79 (31%) | 49 (31%) | 54 (32%) | 25 (30%) | 49 (31%) | ||
| 3+ | 104 (41%) | 78 (49%) | 69 (41%) | 35 (42%) | 78 (49%) | ||
| Operation time, minutes (SD) | 129.8 (65.7) | 127.2 (66.1) | 0.70 | 124.3 (61.9) | 140.5 (71.8) | 127.2 (66.1) | 0.17 |
| Blood loss, cc (SD) | 304.7 (342.7) | 321.9 (487.7) | 0.68 | 303.9 (342.6) | 306.3 (345) | 321.9 (487.7) | 0.92 |
| Blood Replacement | |||||||
| Intraoperative replacement | 27 (11%) | 12 (8%) | 0.40 | 18 (11%) | 9 (11%) | 12 (8%) | 0.60 |
| Post-operative transfusion | 13 (5%) | 7 (4%) | 0.93 | 6 (4%) | 7 (8%) | 7 (4%) | 0.25 |
| Length of hospital stay, days (SD) | 3.3 (2.6) | 3.1 (2.1) | 0.50 | 3.2 (2.5) | 3.5 (2.8) | 3.1 (2.1) | 0.50 |
| Intraoperative complications§ | |||||||
| Dural tear/ spinal fluid leak | 25 (10%) | 13 (8%) | 0.68 | 13 (8%) | 12 (14%) | 13 (8%) | 0.21 |
| Other | 2 (1%) | 1 (1%) | 0.68 | 1 (1%) | 1 (1%) | 1 (1%) | 0.86 |
| None | 224 (89%) | 144 (91%) | 0.65 | 153 (92%) | 71 (85%) | 144 (91%) | 0.17 |
| Postoperative complications/events¶ | |||||||
| Wound hematoma | 3 (1%) | 1 (1%) | 0.97 | 2 (1%) | 1 (1%) | 1 (1%) | 0.86 |
| Wound infection | 6 (2%) | 3 (2%) | 0.98 | 3 (2%) | 3 (4%) | 3 (2%) | 0.64 |
| Other | 14 (6%) | 10 (6%) | 0.90 | 9 (5%) | 5 (6%) | 10 (6%) | 0.93 |
| None | 217 (87%) | 137 (88%) | 0.88 | 147 (89%) | 70 (83%) | 137 (88%) | 0.48 |
| Post-operative mortality (death within 6 weeks of surgery) |
0 (0%) | 1 (0.6%) | 0.82 | 0 (0%) | 0 (0%) | 1 (0.6%) | 0.45 |
| Post-operative mortality (death within 3 months of surgery) |
0 (0%) | 1 (0.6%) | 0.82 | 0 (0%) | 0 (0%) | 1 (0.6%) | 0.45 |
| Additional surgeries (1-year rate)|| | 11 (4%) | 11 (7%) | 0.26 | 7 (4%) | 4 (5%) | 11 (7%) | 0.52 |
| Additional surgeries (2-year rate)|| | 15 (6%) | 17 (10%) | 0.08 | 10 (6%) | 5 (6%) | 17 (10%) | 0.22 |
| Additional surgeries (3-year rate)|| | 21 (8%) | 25 (15%) | 0.02 | 14 (8%) | 7 (8%) | 25 (15%) | 0.07 |
| Additional surgeries (4-year rate)|| | 24 (9%) | 30 (19%) | 0.01 | 17 (10%) | 7 (8%) | 30 (19%) | 0.02 |
| Recurrent stenosis / progressive listhesis | 9 (4%) | 15 (9%) | 7 (4%) | 2 (2%) | 15 (9%) | ||
| Pseudarthrosis / fusion exploration | 0 | 0 | 0 | 0 | 0 | ||
| Complication or Other | 8 (3.2%) | 10 (6.3%) | 5 (3.1%) | 3 (3.5%) | 10 (6.3%) | ||
| New condition | 3 (1.2%) | 5 (3.2%) | 2 (1.2%) | 1 | 5 (3.2%) |
Surgical information was available for 168 patients with duration of symptoms 6 months or less, 84 patients with duration of symptoms 7 to 12 months and 159 patients with duration of symptoms one year or more.
Specific procedure data were available for 165 patients with duration of symptoms 6 months or less, 83 patients with duration of symptoms 7 to 12 months and 154 patients with duration of symptoms more than one year.
No cases were reported of aspiration into the respiratory tract, vascular injury or operation at wrong level.
Complications or events occurring up to 8 weeks after surgery are listed. There were no reported cases of bone-graft complication, cerebrospinal fluid leak, nerve root injury, paralysis, cauda equina injury, pseudarthrosis, wound dehisence.
Rates of repeated surgery at 1, 2,3,and 4 years are Kaplan-Meier estimates. P values were calculated with the use of the log-rank test. Numbers and percentages are based on the first additional surgery if more than one additional surgery.