Chronic Subdural Hematoma Embolization With Detachable Coils (SEED)

July 23, 2026 updated by: Christopher P Kellner, Icahn School of Medicine at Mount Sinai

Safety and Efficacy of Chronic Subdural Hematoma Embolization With Detachable Coils

This is a prospective, multi-center, post market registry study designed to evaluate the safety and efficacy of treatment with Balt coils in patients with chronic subdural hematoma (cSDH).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The primary objective of this observational registry study is to assess the safety and efficacy of Balt Coils as an adjunct to middle meningeal artery (MMA) embolization in a real-world setting among patients undergoing treatment for chronic subdural hematoma (cSDH), and explore correlations between patient characteristics, clinical characteristics, and outcomes. By collecting comprehensive, real-world data, the registry will characterize procedural inputs, document clinical and radiographic outcomes, and explore variation in technique and practice setting. The overarching goal is to generate a more complete understanding of Middle Meningeal Artery Embolization (MMAE) in diverse clinical environments, inform future prospective studies, and guide evidence-based adoption of this evolving therapy. Patients may be treated with Balt coils regardless of enrollment in the study as the decision to place the coils should be made independently as per standard of care and prior to enrollment in the study.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
150

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients with symptomatic chronic subdural hematoma (cSDH), with or without previous surgical evacuation that need additional treatment

Description

Inclusion criteria:

  • Age ≥ 18
  • Patients experiencing unilateral or bilateral non-acute subdural hematoma confirmed by CT imaging. Acute on Chronic or mixed density hematoma allowed.
  • A clinical decision has been made to use coiling and/or embolics as treatment, with or without surgical debridement, independently as per standard of care and prior to enrollment in the study.
  • Signed informed consent obtained by patient or Legal Authorized Representative (LAR)

Exclusion criteria:

  • Primary acute SDH
  • Prior MMAE in target territory
  • Premorbid mRS > 3
  • Common carotid stenosis >70% or prior carotid stent placement
  • Significant medical contraindication to angiography (kidney failure/disease)
  • Anatomical variations that would make MMA embolization difficult or unsafe
  • Currently participating in an investigational (drug, device, etc.) clinical trial that may confound study endpoints
  • Pregnancy
  • Life expectancy ≤ 1 year

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Participants with cSDH

All participants enrolled will be treated with the Balt coils.

  1. MMA embolization: Utilize Balt Coils as stand-alone with or without other embolics treatment.

  2. MMA embolization: Utilize Balt Coils in combination with or without embolics in surgical or bedside evacuation, such as:

    1. MMA embolization in combination with Balt coils post-surgical debridement, or
    2. MMA embolization using Balt coils alone, pre- or post-surgical debridement.
Device: Balt coils: (Balt USA, LLC)
MMA embolization utilizing Balt Coils
Other Names:
  • Optima
  • OptiMax
  • OptiBlock
  • Optima series line extensions
Procedure: MMA embolization

surgical or bedside evacuation

pre or post-surgical debridement

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in hematoma volume
Time Frame: 180 days
Change in hematoma volume based on CT imaging
180 days
Change in maximal thickness
Time Frame: 180 days
Change in maximal thickness based on CT imaging
180 days
Change in midline shift
Time Frame: 180 days
Change in midline shift (mm) based on CT imaging
180 days
Number of periprocedural major disabling stroke or any death
Time Frame: 30 days
Number of periprocedural major disabling stroke or any death
30 days
Number of participants with symptomatic recurrence progression requiring retreatment
Time Frame: 180 days
Number of participants with symptomatic recurrence progression of the SDH requiring retreatment
180 days

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Number of Device-related adverse events (AE), serious adverse events (SAE), and procedural-related SAE
Time Frame: 180 days
Number of Adverse events and serious adverse events related to the device as assessed by an independent medical monitor
180 days
Number of Acute successful embolization of the target vessel
Time Frame: Immediately post-procedure
Determination of successful embolization based on angiographic imaging
Immediately post-procedure
Change in EuroQoL 5 dimensions 5 levels (EQ-5D-5L)
Time Frame: 180 days
The EQ-5D is a generic instrument for describing and valuing health. The new version includes the 5 levels of severity in each of the existing five EQ-5D dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression, and now called the EQ-5D-5L, each assessed on a 5-point scale (1=no problem, 2=slight problems, 3=moderate problems, 4=severe problems, 5=extreme problems). Participants score each dimension based on their health that day and their responses are used to generate a health index score. Index scores could range from <0 (a health state equivalent to dead with negative values representing a state worse than dead) to 1 (full health). Lower scores indicate a higher QoL.
180 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Icahn School of Medicine at Mount Sinai

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
John Muir Health
Carondelet Neurological Institute

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Christopher Kellner, Icahn School of Medicine at Mount Sinai
  • Principal Investigator: Benjamin Yim, John Muir Health
  • Principal Investigator: Alexander Coon, Carondelet Neurological Institute

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 2, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 5, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 5, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 18, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 24, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 23, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • STUDY-25-01365

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Upon the completion of the study, Mount Sinai's data management team will clean and analyze all data in preparation of manuscript writing and publication. Data that will be shared and published will be that of all participants combined to protect individual patient privacy and confidentiality.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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