Table 2.
Surgical Treatments, Complications, and Events.*
| Variable | Randomized Cohort (N = 155) | Observational Cohort (N = 239) | P Value |
|---|---|---|---|
| Procedure — no./total no. (%) | 0.49 | ||
| Decompression only | 137/154 (89) | 209/235 (89) | |
| Noninstrumented fusion | 6/154 (4) | 14/235 (6) | |
| Instrumented fusion | 11/154 (7) | 12/235 (5) | |
| Multilevel fusion — no./total no. (%) | 5/155 (3) | 11/239 (5) | 0.68 |
| Decompression level — no./total no. (%) | |||
| L2-L3 | 53/152 (35) | 90/235 (38) | 0.57 |
| L3-L4 | 115/152 (76) | 157/235 (67) | 0.081 |
| L4-L5 | 140/152 (92) | 218/235 (93) | 0.97 |
| L5-S1 | 60/152 (39) | 89/235 (38) | 0.83 |
| Levels decompressed — no./total no. (%) | 0.92 | ||
| None | 3/155 (2) | 4/239 (2) | |
| 1 | 33/155 (21) | 54/239 (23) | |
| 2 | 47/155 (30) | 78/239 (33) | |
| ≥3 | 72/155 (46) | 103/239 (43) | |
| Operation time — min | 128.4±64.7 | 127.8±66.2 | 0.93 |
| Blood loss — ml | 338.5±527.1 | 295.6±312.6 | 0.31 |
| Blood replacement — no./total no. (%) | |||
| Intraoperative transfusion | 14/152 (9) | 23/238 (10) | 0.98 |
| Postoperative transfusion | 6/153 (4) | 13/238 (5) | 0.65 |
| No. of days in hospital | 3.5±2.6 | 3.0±2.2 | 0.13 |
| Postoperative mortality — no./total no. (%)† | |||
| Within 6 wk | 0/155 | 1/239 (<1) | 0.83 |
| Within 3 mo | 0/155 | 1/239 (<1) | 0.83 |
| Intraoperative complications — no./total no. (%)‡ | |||
| Dural tear or spinal fluid leak | 13/155 (8) | 23/238 (10) | 0.80 |
| Other | 1/155 (1) | 2/238 (1) | 0.71 |
| None | 141/155 (91) | 213/238 (89) | 0.76 |
| Postoperative complications or events — no./total no. (%)§ | |||
| Wound hematoma | 3/153 (2) | 1/238 (<1) | 0.34 |
| Wound infection | 3/153 (2) | 5/238 (2) | 0.79 |
| Other | 8/153 (5) | 13/238 (5) | 0.90 |
| None | 135/153 (88) | 208/238 (87) | 0.93 |
| Additional surgery — no./total no. (%)¶ | |||
| Any surgery | |||
| At 1 yr | 6/157 (4) | 15/243 (6) | 0.29 |
| At 2 yr | 10/157 (6) | 21/243 (9) | 0.39 |
| Recurrent stenosis or progressive spondylolisthesis | |||
| At 1 yr | 3/155 (2) | 2/241 (1) | |
| At 2 yr | 6/155 (4) | 5/241 (2) | |
| Pseudarthrosis or fusion exploration | |||
| At 1 yr | 0/155 | 0/239 | |
| At 2 yr | 0/155 | 0/239 | |
| Complication or other problem | |||
| At 1 yr | 3/155 (2) | 10/241 (4) | |
| At 2 yr | 4/155 (3) | 11/241 (5) | |
| New condition | |||
| At 1 yr | 0/155 | 2/241 (1) | |
| At 2 yr | 1/155 (1) | 5/241 (2) |
Plus—minus values are means ±SD. A total of 157 patients in the randomized cohort and 243 patients in the observational cohort underwent surgery. Data are missing for patients in some categories, as indicated by varying denominators.
One patient had a myocardial infarction.
None of the following were reported: aspiration, nerve-root injury, operation at wrong level, and vascular injury.
This category includes all reported complications up to 8 weeks after surgery. None of the following were reported: bone-graft complication, cerebrospinal fluid leak, paralysis, cauda equina injury, wound dehiscence, pseudarthrosis, and nerve-root injury.
Rates of repeated surgery at 1 and 2 years are Kaplan—Meier estimates. P values were calculated with the use of the log-rank test.