Lumbar epidural blood patch: effectiveness on orthostatic headache and MRI predictive factors in 101 consecutive patients affected by spontaneous intracranial hypotension.

Although epidural blood patch (EBP) is considered the gold-standard treatment for drug-resistant orthostatic headache in spontaneous intracranial hypotension (SIH), no clear evidence exists regarding the best administration method of this technique (blind vs target procedures). The aim of this study was to assess the long-term efficacy of blind lumbar EBP and predictors on preoperative MRI of good outcome. Lumbar EBP was performed by injecting 10 ml of autologous venous blood, fibrin glue, and contrast medium in 101 consecutive patients affected by SIH and orthostatic headache. Visual analog scale (VAS) scores for headache were recorded preoperatively, at 48 hours and 6 months after the procedure, and by telephone interview in July 2017. Patients were defined as good responders if a VAS score reduction of at least 50% was achieved within 48 hours of the procedure and lasted for at least 6 months. Finally, common radiological SIH findings were correlated with clinical outcomes. The median follow-up was 60 months (range 8-135 months); 140 lumbar EBPs were performed without complications. The baseline VAS score was 8.7 ± 1.3, while the mean VAS score after the first EBP procedure was 3.5 ± 2.2 (p < 0.001). The overall response rate at the 6-month follow-up was 68.3% (mean VAS score 2.5 ± 2.4, p < 0.001). Symptoms recurred in 32 patients (31.7%). These patients underwent a second procedure, with a response rate at the 6-month follow-up of 78.1%. Seven patients (6.9%) did not improve after a third procedure and remained symptomatic. The overall response rate at the last follow-up was 89.1% with a mean VAS score of 2.7 ± 2.3 (p < 0.001). The only MRI predictors of good outcome were location of the iter > 2 mm below the incisural line (p < 0.05) and a pontomesencephalic angle (PMA) < 40° (p < 0.05). Lumbar EBP may be considered safe and effective in cases of drug-refractory SIH. The presence of a preprocedural PMA < 40° and location of the iter > 2 mm below the incisural line were the most significant predictors of good outcome. Randomized prospective clinical trials comparing lumbar with targeted EBP are warranted to validate these results.