Table 2.
Degenerative Spondylolisthesis (DS) Operative treatments, complications and events*
| DS | (BMI<30) (n=233) |
(30≤BMI<35) (n=90) |
(BMI≥35) (n=66) |
p-value |
|---|---|---|---|---|
| Specific procedures† | 0.17 | |||
| Decompression only | 20 (9%) | 2 (2%) | 2 (3%) | |
| Non-instrumented fusion | 45 (20%) | 20 (22%) | 16 (25%) | |
| Instrumented fusion | 163 (71%) | 67 (75%) | 47 (72%) | |
| Multi-level fusion | 51 (22%) | 27 (30%) | 13 (20%) | 0.22 |
| Decompression level | ||||
| L2–L3 | 26 (11%) | 13 (15%) | 6 (9%) | 0.52 |
| L3–L4 | 119 (52%) | 46 (53%) | 24 (38%) | 0.099 |
| L4–L5 | 225 (97%) | 88 (100%) | 61 (94%) | 0.076 |
| L5-S1 | 71 (31%) | 26 (30%) | 16 (25%) | 0.61 |
| Levels decompressed | 0.35 | |||
| None | 1 (0%) | 2 (2%) | 1 (2%) | |
| 1 | 91 (39%) | 34 (38%) | 34 (52%) | |
| 2 | 85 (36%) | 32 (36%) | 21 (32%) | |
| 3+ | 56 (24%) | 22 (24%) | 10 (15%) | |
| Operation time, minutes (SD) | 197.2 (78.5) | 218.4 (91.6) | 222.7 (85.8) | 0.028 |
| Blood loss, cc (SD) | 545.4 (474.6) | 644.9 (492.7) | 624.5 (407.2) | 0.17 |
| Blood Replacement | ||||
| Intraoperative replacement | 70 (30%) | 35 (39%) | 27 (41%) | 0.14 |
| Post-operative transfusion | 52 (23%) | 14 (16%) | 15 (23%) | 0.40 |
| Length of hospital stay, days (SD) | 4.4 (2.6)** | 5 (3.5) | 5.3 (3.9) | 0.069 |
| Intraoperative complications§ | ||||
| Dural tear/ spinal fluid leak | 33 (14%) | 5 (6%) | 3 (5%) | 0.017 |
| Vascular injury | 1 (0%) | 0 (0%) | 0 (0%) | 0.71 |
| Other | 7 (3%) | 2 (2%) | 0 (0%) | 0.36 |
| None | 194 (83%) | 83 (92%) | 63 (95%) | 0.009 |
| Postoperative complications/events¶ | ||||
| Nerve root injury | 1 (0%) | 0 (0%) | 0 (0%) | 0.72 |
| Wound dehiscence | 0 (0%) | 1 (1%) | 0 (0%) | 0.19 |
| Wound hematoma | 0 (0%) | 0 (0%) | 1 (2%) | 0.085 |
| Wound infection | 3 (1%) | 3 (3%) | 5 (8%) | 0.023 |
| Other | 20 (9%) | 11 (12%) | 6 (9%) | 0.58 |
| None | 165 (71%) | 62 (70%) | 40 (62%) | 0.30 |
| Post-operative mortality (death within 6 weeks of surgery) | 1 (0.4%) | 0 (0%) | 0 (0%) | 0.72 |
| Post-operative mortality (death within 3 months of surgery) | 1 (0.4%) | 0 (0%) | 1 (1.5%) | 0.40 |
| Additional surgeries (1-year rate)‖ | 10 (4%) | 8 (9%) | 7 (11%) | 0.08 |
| Additional surgeries (2-year rate) ‖ | 23 (10%) | 14 (15%) | 11 (17%) | 0.15 |
| Additional surgeries (3-year rate) ‖ | 24 (10%) | 18 (20%) | 12 (18%) | 0.04 |
| Additional surgeries (4-year rate) ‖ | 27 (11%) | 19 (21%) | 13 (20%) | 0.04 |
| Recurrent stenosis / progressive listhesis | 14 (6%) | 3 (3%) | 3 (5%) | |
| Pseudarthrosis / fusion exploration | 0 | 2 (2.2%) | 2 (3.1%) | |
| Complication or Other | 9 (3.9%) | 9 (10.1%) | 7 (10.9%) | |
| New condition | 4 (1.7%) | 4 (4.5%) | 1 |
Surgical information was available for 233 (BMI<30), 90 (30≤BMI<35), and 66 (BMI≥35) patients.
Specific procedure data was available for 228 (BMI<30), 89 (30≤BMI<35), and 65 (BMI≥35) patients.
No cases were reported of aspiration into the respiratory tract 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, paralysis, cauda equina injury or pseudarthrosis.
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.
One of the patients in BMI<30 group had a length of hospital stay of 372 days—not counting that case the average length of hospital stay for the BMI<30 group would be 4.4 (2.6).