Epidural fibrosis and its role in the structure of complications in repeated surgical interventions on the lumbar spine

Objective. To conduct a multifactorial assessment of the risks of intraoperative damage to the dura mater (DM) in patients who underwent primary and repeated interventions on the lumbar spine. Material and Methods. A retrospective comparative analysis of data from two groups of patients who underwent repeated (n = 144) and primary (n = 153) surgery for degenerative diseases of the lumbar spine was conducted. All surgeries were performed by two experienced surgeons using a standard posterior approach, intraoperative fluoroscopy, microsurgical techniques and binocular magnification. Intraoperative (presence of adhesions, damage to the dura mater, duration of surgery, blood loss, approach and stabilization) and clinical and anamnestic data (gender, age, body mass index, diagnosis, blood transfusion and revisions) were analyzed. Damage to the dura mater was assessed intraoperatively, during revision and based on MRI data. Statistical analysis was performed using the binary logistic regression model. Results. In repeated surgeries, epidural fibrosis was observed in 92.36% of patients, which significantly increased the risk of dura mater injury as compared to primary surgeries (15.2% vs. 1.9%; p < 0.001). According to multivariate analysis, the extent of surgical access does not have a statistically significant effect on dura mater injury. The presence of fibrosis increases the risk of injury by 4 times, while spine stabilization reduces it by 6 times. The effect of surgery duration on the risk of dura mater injury was not statistically proven. The main limitation of the study is the insufficient postoperative MRI screening, which may lead to the underestimation of the incidence of complications. Conclusion. Epidural fibrosis is a key risk factor for damage to the dura mater during revision surgery. Its prevention is a pressing issue in surgery for lumbar spine dorsopathies.