Table 4.
Intervertebral Disc Herniation (IDH) Operative treatments, complications and events*
| IDH | (BMI<30) (n=552) |
(30≤BMI<35) (n=151) |
(BMI≥35) (n=94) |
p-value |
|---|---|---|---|---|
| Discectomy Level - no. (%) | ||||
| L2–L3 | 11 (2%) | 2 (1%) | 1 (1%) | 0.75 |
| L3–L4 | 20 (4%) | 2 (1%) | 5 (5%) | 0.21 |
| L4–L5 | 202 (37%) | 71 (48%) | 39 (42%) | 0.045 |
| L5-S1 | 323 (59%) | 78 (53%) | 52 (56%) | 0.36 |
| Operation time, minutes (SD) | 72.3 (33.5) | 84 (39.2) | 90.5 (49.6) | <0.001 |
| Blood loss, cc (SD) | 56.1 (90.8) | 84.8 (137.7) | 80.7 (90) | 0.002 |
| Blood Replacement - no. (%) | ||||
| Intraoperative replacement | 5 (1%) | 1 (1%) | 0 (0%) | 0.64 |
| Post-operative transfusion | 0 (0%) | 0 (0%) | 0 (0%) | |
| Length of hospital stay, days (SD) | 0.89 (0.8) | 1.2 (1.2) | 1.1 (1.2) | <0.001 |
| Intraoperative complications - no. (%)§ | ||||
| Dural tear/ spinal fluid leak | 14 (3%) | 7 (5%) | 3 (3%) | 0.41 |
| Nerve root injury | 1 (0%) | 0 (0%) | 1 (1%) | 0.23 |
| Other | 1 (0%) | 1 (1%) | 1 (1%) | 0.35 |
| None | 536 (97%) | 144 (95%) | 89 (95%) | 0.35 |
| Postoperative complications/events - no. (%)¶ | ||||
| Nerve root injury | 0 (0%) | 0 (0%) | 1 (1%) | 0.024 |
| Wound hematoma | 3 (1%) | 1 (1%) | 0 (0%) | 0.75 |
| Wound Infection | 13 (2%) | 3 (2%) | 2 (2%) | 0.96 |
| Other | 18 (3%) | 7 (5%) | 2 (2%) | 0.55 |
| None | 516 (94%) | 141 (93%) | 89 (95%) | 0.90 |
| Post-operative mortality (death within 6 weeks of surgery) - no. (%) | 0 (0%) | 0 (0%) | 0 (0%) | |
| Post-operative mortality (death within 3 months of surgery) - no. (%) | 1 (0.2%)‡ | 0 (0%) | 0 (0%) | 0.8 |
| Additional surgeries (1-year rate) - no. (%)‖ | 32 (6%) | 8 (5%) | 6 (6%) | 0.93 |
| Additional surgeries (2-year rate) - no. (%)‖ | 40 (7%) | 15 (10%) | 9 (10%) | 0.49 |
| Additional surgeries (3-year rate) - no. (%)‖ | 43 (8%) | 18 (12%) | 10 (11%) | 0.26 |
| Additional surgeries (4-year rate) - no. (%)‖ | 51 (9%) | 18 (12%) | 13 (14%) | 0.31 |
| Recurrent disc herniation | 32 (6%) | 10 (7%) | 7 (8%) | |
| Complication or Other | 13 (2%) | 4 (3%) | 4 (4%) | |
| New condition | 4 (1%) | 4 (3%) | 1 |
Surgical information was available for 552 (BMI<30), 151 (30≤BMI<35), and 94 (BMI≥35) patients.
None of the following were reported: aspiration, 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, paralysis, cauda equina injury, wound dehiscence, pseudarthrosis.
One-, two-, three- and four-year post-surgical re-operation rates are Kaplan Meier estimates. 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.
Patient died after heart surgery at another hospital, the death was judged unrelated to spine surgery.