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

Abstract

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%, n = 128). A few compared the efficacy of different treatments (10.8%, n = 15). Most used objective methods for the diagnosis of spontaneous intracranial hypotension (62.3%, n = 86); however, 37.7% (n = 52) did not clearly meet the International Classification of Headache Disorders-3 criteria. CSF leak type was unclear in 77.7% (n = 108). Nearly all reported patient symptoms using unvalidated measures (84.9%, n = 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.

FIG 1.

Evidence map or the Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow chart. The asterisk indicates Martin 2019, Ohtonari 2012, Urbach 2020, Beck 2019, Pagani-Estevez 2019, Levi 2019, Franzini 2013, Watanabe 2011, Beck 2019, Angelo 2011; hash, Ferrante 2016, Ferrante 2015.

FIG 2.

Timeline of included publications.

FIG 3.

Countries of origin for included studies.

FIG 4.

Evidence map of studies investigating treatments for SIH that included epidural patching and describing imaging-guidance methods. Note that each circle represents a single study with the area of the circle proportional to the study sample size; and colors represent the method of assessing a patient’s symptomatic response in each study, either a validated outcome measure (blue), subjective (nonvalidated) assessment (orange), or not reported (gray). RCT indicates randomized controlled trial.

FIG 5.

Evidence map of studies investigating treatments in SIH that included epidural patching and described the patching material used. RCT indicates randomized controlled trial.

FIG 6.

Evidence map of studies investigating treatments in SIH that included epidural patching and described targeted or nontargeted approaches. RCT indicates randomized controlled trial.

FIG 7.

Evidence map of studies investigating treatments in SIH that included surgery. RCT indicates randomized controlled trial.

FIG 8.

Methods of SIH diagnosis and types of CSF leaks.

FIG 9.

Outcome measures.