Efficacy of Epidural Blood Patching or Surgery in Spontaneous Intracranial Hypotension: A Systematic Review and Evidence Map.

Background: Spontaneous intracranial hypotension is an important cause of treatable secondary headaches. Evidence on the efficacy of epidural blood patching and surgery for spontaneous intracranial hypotension has not been synthesized.

Purpose: Our aim was to identify evidence clusters and knowledge gaps in the efficacy of treatments for spontaneous intracranial hypotension to prioritize future research.

Data Sources: We searched published English language articles on MEDLINE (Ovid), the Web of Science (Clarivate), and EMBASE (Elsevier) from inception until October 29, 2021.

Study Selection: We reviewed experimental, observational, and systematic review studies assessing the efficacy of epidural blood patching or surgery in spontaneous intracranial hypotension.

Data Analysis: One author performed data extraction, and a second verified it. Disagreements were resolved by consensus or adjudicated by a third author.

Data Synthesis: One hundred thirty-nine studies were included (median, 14 participants; range, 3-298 participants). Most articles were published in the past decade. Most assessed epidural blood patching outcomes. No studies met level 1 evidence. Most were retrospective cohort or case series (92.1%, = 128). A few compared the efficacy of different treatments (10.8%, = 15). Most used objective methods for the diagnosis of spontaneous intracranial hypotension (62.3%, = 86); however, 37.7% ( = 52) did not clearly meet the International Classification of Headache Disorders-3 criteria. CSF leak type was unclear in 77.7% ( = 108). Nearly all reported patient symptoms using unvalidated measures (84.9%, = 118). Outcomes were rarely collected at uniform prespecified time points.

Limitations: The investigation did not include transvenous embolization of CSF-to-venous fistulas.

Conclusions: Evidence gaps demonstrate a need for prospective study designs, clinical trials, and comparative studies. We recommend using the International Classification of Headache Disorders-3 diagnostic criteria, explicit reporting of CSF leak subtype, inclusion of key procedural details, and using objective validated outcome measures collected at uniform time points.