Low cerebrospinal fluid pressure predisposes to postoperative epidural hematoma following lumbar decompression: a potentially modifiable physiological risk factor

Postoperative spinal epidural hematoma (SEH) is a serious complication of lumbar spinal surgery. While various risk factors have been reported, the role of cerebrospinal fluid (CSF) pressure in SEH development remains unclear. This study aimed to investigate the association between preoperative CSF pressure and postoperative SEH, and to explore potentially modifiable physiological factors. A total of 94 patients undergoing lumbar decompression surgery were retrospectively reviewed. Preoperative CSF pressure was measured via lumbar puncture in the lateral position before surgery. Patients were categorized into hematoma and no-hematoma groups based on postoperative magnetic resonance imaging findings. Clinical and surgical variables were compared between groups, and multivariable logistic regression analysis was performed to identify independent risk factors for SEH. Postoperative epidural hematoma with significant dural sac compression was observed in 30.8% of patients. Multivariable logistic regression analysis revealed that lower CSF pressure (adjusted OR = 0.87 per 10 mmH2O increase; 95% CI: [0.74–0.98], P = 0.028) and the number of decompressed levels (adjusted OR = 1.94; 95% CI: [1.15–3.47], P = 0.017) were independently associated with SEH development. Post hoc power analysis for CSF pressure yielded sufficient power of 0.81. Low preoperative CSF pressure was independently associated with postoperative SEH and may represent a potentially modifiable physiological factor. Perioperative strategies aimed at maintaining adequate CSF pressure may help reduce the risk of postoperative epidural hematoma, although their clinical effectiveness requires confirmation in prospective studies.