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Common data elements reported on middle meningeal artery embolization in chronic subdural hematoma: an interactive systematic review of recent trials
  1. Gautam Adusumilli1,
  2. Sherief Ghozy2,
  3. Kevin M Kallmes3,
  4. Nicole Hardy3,
  5. Ranita Tarchand3,
  6. Caleb Zinn3,
  7. Duncan Lamar3,
  8. Emily Singeltary3,
  9. Lauren Siegel3,
  10. David F Kallmes4,
  11. Adam S Arthur5,6,
  12. Susanne Gellissen7,
  13. Jens Fiehler8,
  14. Jeremy J Heit9
  1. 1 Department of Radiology and Neurosurgery, Stanford University, Stanford, California, USA
  2. 2 Department of Radiology, Mayo Clinic Minnesota, Rochester, Minnesota, USA
  3. 3 Nested Knowledge Inc, Saint Paul, Minnesota, USA
  4. 4 Radiology, Mayo Clinic, Rochester, Minnesota, USA
  5. 5 Semmes-Murphey Neurologic and Spine Institute, Memphis, Tennessee, USA
  6. 6 Neurosurgery, University of Tennessee Health Science Center, Memphis, Tennessee, USA
  7. 7 Department of Diagnostic and Interventional Neuroradiology, Universitatsklinikum Hamburg Eppendorf Klinik und Poliklinik fur Neuroradiologische Diagnostik und Intervention, Hamburg, Germany
  8. 8 Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
  9. 9 Radiology, Neuroadiology and Neurointervention Division, Stanford University, Stanford, California, USA
  1. Correspondence to Mr Kevin M Kallmes, 1430 Avon Street North, Saint Paul, Minnesota 55117, USA; kevinkallmes{at}


Cross study heterogeneity has limited the evidence based evaluation of middle meningeal artery embolization (MMAE) as a treatment for chronic subdural hematoma (CSDH). Ongoing trials and prospective studies suggest that heterogeneity in upcoming publications may detract from subsequent meta-analyses and systemic reviews. This study aims to describe this data heterogeneity to promote harmonization with common data elements (CDEs) in publications. and PubMed were searched for published or ongoing prospective trials of MMAE. The Nested Knowledge AutoLit living review platform was utilized to classify endpoints from randomized control trials (RCTs) and prospective cohort studies comparing MMAE with other treatments. The qualitative synthesis feature was used to determine cross study overlap of outcome related data elements. Eighteen studies were included: 12 RCTs, two non-randomized controlled studies, two prospective single arm trials, one combined prospective and retrospective controlled study, and one prospective cohort study. The most commonly reported data element was recurrence (15/18), but seven heterogenous (non-comparable) definitions were used for ‘recurrence’. Mortality was reported in 10/18 studies, but no common timepoint was reported in more than four studies. Re-intervention and CSDH volume were reported in eight studies, CSDH width in seven, and no other outcome was common across more than five studies. There was significant heterogeneity in data element collection even among prospective registered trials of MMAE. Even among CDEs, variation in definition and timepoints prevented harmonization. A standardized approach based on CDEs may be necessary to facilitate future meta-analyses and evidence driven evaluation of MMAE treatment of CSDH.

  • technology
  • brain
  • subdural
  • embolic

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  • GA and SG contributed equally.

  • Contributors All authors contributed to the study design and drafting of the manuscript. Search was completed by KMK, screening of articles by CS and DL, data extraction by GA, SG, KMK, and RT, with quality control by NH, SG, JF, and JH. Statistical analysis was provided by JP, and all authors contributed to feedback and finalization of the manuscript.

  • Funding Funding for the research and data gathering efforts were provided by Balt USA Inc.

  • Competing interests JJH is a consultant for Medtronic and MicroVention and is a member of the scientific and medical advisory board for iSchemaView. KMK works for and holds equity in Nested Knowledge Inc, works for Conway Medical LLC, and holds equity in Superior MedicalExperts Inc. NH works for and holds equity in Nested Knowledge Inc. ES and LS work for Nested Knowledge Inc. DFK has the following conflicts: ownership in Nested Knowledge Inc, Superior Medical Experts Inc, and Conway Medical LLC; research support from Microvention, Balt USA, and Medtronic. JF has the following conflicts: Imaging Core Lab for EMBOLISE (sponsor: Medtronic); research support from German Ministry of Science and Education (BMBF), German Ministry of Economy and Innovation (BMWi), German Research Foundation (DFG), European Union (EU), Hamburgische Investitions- und Förderbank (IFB), Medtronic, Microvention, Route92, and Stryker; consultant for Acandis, Bayer, Boehringer Ingelheim, Cerenovus, Covidien, Medtronic, Medina, Microvention, Penumbra, Phenox, Stryker, and Transverse Medical; stock holder in Tegus Medical; deputy editor of J Neurointerv Surg. ASA is the primary investigator of the STEM Trial.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.