The impact of hypertension on the occurrence of postoperative spinal epidural hematoma following single level microscopic posterior lumbar decompression surgery in a single institute.

PURPOSE: Postoperative spinal epidural hematoma (PSEH) is one of the most hazardous complications after spine surgery. A recent study has reported that a ≥50 mmHg increase in systolic blood pressure after extubation was a significant risk factor for symptomatic PSEH. In this paper, the impact of hypertension on PSEH occurrence was investigated. METHODS: Among a total of 2468 patients who underwent single level microscopic posterior decompression surgery for lumbar spinal stenosis in a single institute, 15 (0.6%) received evacuation surgery for PSEH. Those 15 patients were investigated statistically compared with a randomly selected control group (n = 46) using the Mann-Whitney U test and multiple logistic regression analysis. RESULTS: The univariate analysis showed that there were no significant differences in age, gender, BMI, pre-operative anti-coagulant usage, intraoperative blood loss, operation time, and the rate of patients who received pre-operative hypertension treatment. However, there were significant differences in the rate of patients who showed high blood pressure at admission (66.7 vs 6.5%) and >50 mmHg increases in blood pressure after extubation (53.3 vs 17.4%) in the univariate analysis. Moreover, postoperatively, there was a statistical difference in the amount of post-operative drainage. Multiple logistic regression analysis showed that high blood pressures at admission and poor postoperative drainage were the essential risk factors. CONCLUSIONS: Our results demonstrate that the pre-operative high blood pressure value was the most essential risk factor for PSEH, although there was no difference in the preoperative hypertension treatment. Consequently, management of pre-operative blood pressure and post-operative drainage will be crucial for preventing PSEH.