Chronic Subdural HematomaSWEMMANCT05267184
Swedish Trial on Embolization of Middle Meningeal Artery Versus Surgical Evacuation in Chronic Subdural Hematoma
A study testing Endovascular treatment of the middle meningeal artery and Standard neurosurgical hematoma evacuation in people with Chronic Subdural Hematoma, run by Region Skane at 4 sites in Sweden.
Trial summary
The SWEMMA trial is an open, national, multi-center, prospective, randomized (1:1), superiority trial designed to assess impact on reoperation rates for chronic subdural hematoma with a head-to-head comparison of embolization of the middle meningeal artery (intervention) with standard neurosurgical hematoma evacuation… Read more about this study
- Who is it for?
- Ages 18 to 89 years
- Conditions the study is for
- Chronic Subdural Hematoma
- What is being tested?
- Endovascular treatment of the middle meningeal artery and Standard neurosurgical hematoma evacuation
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 288 participants
- Where
- 4 sitesSweden
- Study dates
- 28 Mar 2022to Sep 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 89 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Men and women 18-89 y/o
- Non-contrast Computed Tomography (NCCT)- or Magnetic Resonance Imaging (MRI)- verified, previously unoperated uni- or bilateral cSDH
- Clinical and/or radiological status indicating neurosurgical treatment
- Markwalder Scale score <2
- Glasgow coma Scale score >13
- Able to provide signed informed consent
Who cannot join
- Acute subdural hematoma
- Focal, non-hemispheric cSDH
- Midline shift >10 mm and/or effaced basal cisterns and/or significant dilatation of one or both lateral ventricle temporal horns and/or incipient uncal herniation
- Structural pathology causing the cSDH (e.g. dural AV-fistula, AVM, tumor, arachnoid cyst, ventriculoperitoneal shunt)
- Contraindications to angiography
- Dependency defined as mRS >3
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- Life expectancy <6 months
- Comorbidity deemed making follow up impossible
- Participation in other interventional clinical study
- Pregnancy
Trial locations and contacts
4 sites in 1 country.
Sweden4 sites
Sahlgenska University Hospital
Gothenburg, 41345
Skåne University Hospital
Lund, 22185
Karolinska Hospital
Stockholm, 17176
Norrlands Universitetssjukhus
Umeå, 90737
About this study
The SWEMMA trial is an open, national, multi-center, prospective, randomized (1:1), superiority trial designed to assess impact on reoperation rates for chronic subdural hematoma with a head-to-head comparison of embolization of the middle meningeal artery (intervention) with standard neurosurgical hematoma evacuation (control).
Read the detailed description
Introduction: Chronic subdural hematoma (CSDH) is one of the most common neurosurgical disorders and the incidence is rising. The mainstay of treatment is neurosurgical hematoma evacuation followed by postoperative drainage but recurrence and reoperation rates are as high as 10-30%. Embolization of the middle meningeal artery (EMMA) has been proposed as an adjunct or as sole therapy and initial data suggests markedly reduced reoperation rates. Several randomised trials are currently underway, mostly randomizing with EMMA as an adjunctive to evacuation, or as an alternative to conservative treatment. This trial aims to make a head-to-head comparison of neurosurgical evacuation versus EMMA.
Aims: The primary objective of the trial is to compare efficacy of EMMA on rates of reoperation by randomizing patients with CSDH and mild to moderate symptoms to either EMMA or standard neurosurgical evacuation. Secondary objectives include all complication rate, technical success rate, residual hematoma volume at 3 months, neurological functionality and quality of life at 3 and 12 months and composite endpoint of death or reoperation at 3 and 12 months.
Method: Patients with previously untreated CSDH admitted to the neurosurgical unit at participating centers with clinical and/or radiological indication for neurosurgical evacuation, mild to moderate symptoms and able to provide informed consent, will be randomized to either standard treatment or EMMA. Immediately after either procedure the participant returns to standard clinical care. At 3 months a CT of the head is performed. A structured telephone interview is held by a treatment-blinded outcomes assessor at 3 months and 12 months, measuring quality of life (EQ-5D) and neurological disability (mRS). Medical records are collected and assessed at 3 months regarding safety measures. Data on reoperation and mortality are collected from the National Board of Health and Welfare and National Cause of Death Registry at 3 months and 12 months.
- Conditions
- Chronic Subdural Hematoma
- Being tested
- Endovascular treatment of the middle meningeal artery, Standard neurosurgical hematoma evacuation
- Medical subject headings
- Hematoma, Subdural, Chronic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Endovascular treatment of the middle meningeal arteryProcedure or surgery
The middle meningeal artery on the same side(s) as the chronic subdural hematoma is embolized with liquid embolic agents.
Standard neurosurgical hematoma evacuationProcedure or surgery
Also called burr-hole, mini craniotomy
Standard neurosurgical evacuation of chronic subdural hematoma through burr-hole or mini craniotomy and postoperative subdural or subgaleal drainage.
| Study group | Role | What they receive |
|---|---|---|
| Embolization of middle meningeal artery | Experimental | Participants receive endovascular treatment with embolization of the middle meningeal artery ipsilaterally to the chronic subdural hematoma(s). Receives: Procedure: Endovascular treatment of the middle meningeal artery |
| Standard neurosurgical hematoma evacuation and drainage | Active comparator | Participants receive standard neurosurgical hematoma evacuation via burr hole or mini craniotomy and post-operative subdural or subgaleal drainage. Receives: Procedure: Standard neurosurgical hematoma evacuation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Reoperation
Reoperation rate of CSDH between groups
Measured: 3 months
Secondary outcomes (6)
Neurological disability
Assessed by the modified Rankin Scale (mRS). Numerical scale with scores between 0 and 6 (0 = no symptoms, 6= death)
Measured: 3 months and 12 months
Quality of Life (EQ-5D)
Assessed by the EuroQol EQ-5D scale
Measured: 3 months and 12 months
Residual hematoma volume
Change in hematoma volume from pre-, post operative, and follow up head CT
Measured: 3 months
Technical success rate
Rate of technically successful embolizations performed
Measured: 24 hours
Procedure related complication rate (Safety)
Difference in number and severity of complications between endovascular and surgical participants
Measured: 3 months
Composite endpoint
Death or reoperation
Measured: 3 and 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Mar 2022
- Study start28 Mar 2022
- Primary completionDec 2026 (estimated)
- Study completionSep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Chronic Subdural HematomaStudies of the same condition, open and under way.
- More trials run by Region SkaneThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 288 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Region Skane
- Sponsor type
- University, hospital or other
- Collaborators
- Lund University, Sahlgrenska University Hospital, Karolinska University Hospital, Norrlands University Hospital
- Responsible party
- Sponsor
- Investigators
- Mattias Drake, MD, Principal investigator, Skåne University Hospital, Lund University, Lund SwedenJohan Wassélius, MD, PhD, Study director, Skåne University Hospital, Lund University, Lund Sweden
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05267184
- Sponsor's protocol ID
- 2021/02670
- Acronym
- SWEMMA
- Status last verified
- Sep 2026
- First submitted
- 24 Feb 2022
- Last updated
- 14 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Drake M, Ullberg T, Nittby H, Marklund N, Wasselius J. Swedish trial on embolization of middle meningeal artery versus surgical evacuation in chronic subdural hematoma (SWEMMA)-a national 12-month multi-center randomized controlled superiority trial with parallel group assignment, open treatment allocation and blinded clinical outcome assessment. Trials. 2022 Nov 8;23(1):926. doi: 10.1186/s13063-022-06842-4.
PubMed 36348417
Study at a glance
From the registry record, last updated by the sponsor on 14 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Swedish Trial on Embolization of Middle Meningeal Artery Versus Surgical Evacuation in Chronic Subdural Hematoma
- ClinicalTrials.gov ID
- NCT05267184
- Acronym / sponsor ID
- SWEMMA / 2021/02670
- Conditions
- Chronic Subdural Hematoma
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 288 participants (estimated)
- Lead sponsor
- Region SkaneUniversity, hospital or other
- Collaborators
- Lund University, Sahlgrenska University Hospital, Karolinska University Hospital, Norrlands University Hospital
- Study start
- 28 Mar 2022 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Sep 2027 (estimated)
- First posted
- 4 Mar 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The SWEMMA trial is an open, national, multi-center, prospective, randomized (1:1), superiority trial designed to assess impact on reoperation rates for chronic subdural hematoma with a head-to-head comparison of embolization of the middle meningeal artery (intervention) with standard neurosurgical hematoma evacuation (control).
Detailed description
Introduction: Chronic subdural hematoma (CSDH) is one of the most common neurosurgical disorders and the incidence is rising. The mainstay of treatment is neurosurgical hematoma evacuation followed by postoperative drainage but recurrence and reoperation rates are as high as 10-30%. Embolization of the middle meningeal artery (EMMA) has been proposed as an adjunct or as sole therapy and initial data suggests markedly reduced reoperation rates. Several randomised trials are currently underway, mostly randomizing with EMMA as an adjunctive to evacuation, or as an alternative to conservative treatment. This trial aims to make a head-to-head comparison of neurosurgical evacuation versus EMMA.
Aims: The primary objective of the trial is to compare efficacy of EMMA on rates of reoperation by randomizing patients with CSDH and mild to moderate symptoms to either EMMA or standard neurosurgical evacuation. Secondary objectives include all complication rate, technical success rate, residual hematoma volume at 3 months, neurological functionality and quality of life at 3 and 12 months and composite endpoint of death or reoperation at 3 and 12 months.
Method: Patients with previously untreated CSDH admitted to the neurosurgical unit at participating centers with clinical and/or radiological indication for neurosurgical evacuation, mild to moderate symptoms and able to provide informed consent, will be randomized to either standard treatment or EMMA. Immediately after either procedure the participant returns to standard clinical care. At 3 months a CT of the head is performed. A structured telephone interview is held by a treatment-blinded outcomes assessor at 3 months and 12 months, measuring quality of life (EQ-5D) and neurological disability (mRS). Medical records are collected and assessed at 3 months regarding safety measures. Data on reoperation and mortality are collected from the National Board of Health and Welfare and National Cause of Death Registry at 3 months and 12 months.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Embolization of middle meningeal artery | Experimental | Procedure: Endovascular treatment of the middle meningeal arteryParticipants receive endovascular treatment with embolization of the middle meningeal artery ipsilaterally to the chronic subdural hematoma(s). |
| Standard neurosurgical hematoma evacuation and drainage | Active comparator | Procedure: Standard neurosurgical hematoma evacuationParticipants receive standard neurosurgical hematoma evacuation via burr hole or mini craniotomy and post-operative subdural or subgaleal drainage. |
Who may qualify
- Ages
- 18 to 89 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Men and women 18-89 y/o
- Non-contrast Computed Tomography (NCCT)- or Magnetic Resonance Imaging (MRI)- verified, previously unoperated uni- or bilateral cSDH
- Clinical and/or radiological status indicating neurosurgical treatment
- Markwalder Scale score <2
- Glasgow coma Scale score >13
Key exclusion criteria (10 listed)
- Acute subdural hematoma
- Focal, non-hemispheric cSDH
- Midline shift >10 mm and/or effaced basal cisterns and/or significant dilatation of one or both lateral ventricle temporal horns and/or incipient uncal herniation
- Structural pathology causing the cSDH (e.g. dural AV-fistula, AVM, tumor, arachnoid cyst, ventriculoperitoneal shunt)
- Contraindications to angiography
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Endovascular treatment of the middle meningeal arteryThe middle meningeal artery on the same side(s) as the chronic subdural hematoma is embolized with liquid embolic agents. | Procedure or surgery | Embolization of middle meningeal artery |
| Standard neurosurgical hematoma evacuationAlso: burr-hole, mini craniotomyStandard neurosurgical evacuation of chronic subdural hematoma through burr-hole or mini craniotomy and postoperative subdural or subgaleal drainage. | Procedure or surgery | Standard neurosurgical hematoma evacuation and drainage |
Primary outcome
Reoperation
Time frame: 3 months
Reoperation rate of CSDH between groups
6 secondary outcomes
Neurological disability
Time frame: 3 months and 12 months
Quality of Life (EQ-5D)
Time frame: 3 months and 12 months
Residual hematoma volume
Time frame: 3 months
Technical success rate
Time frame: 24 hours
Procedure related complication rate (Safety)
Time frame: 3 months
Composite endpoint
Time frame: 3 and 12 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Sep 2026.
- Derived from this study: PubMed 36348417Drake M, Ullberg T, Nittby H, Marklund N, Wasselius J. Swedish trial on embolization of middle meningeal artery versus surgical evacuation in chronic subdural hematoma (SWEMMA)-a national 12-month multi-center randomized controlled superiority trial with parallel group assignment, open treatment allocation and blinded clinical outcome assessment. Trials. 2022 Nov 8;23(1):926. doi: 10.1186/s13063-022-06842-4.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Mattias Drake, MD principal investigator
Skåne University Hospital, Lund University, Lund Sweden
Johan Wassélius, MD, PhD study director
Skåne University Hospital, Lund University, Lund Sweden
4 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Endovascular treatment of the middle meningeal artery and Standard neurosurgical hematoma evacuation in people with Chronic Subdural Hematoma, run by Region Skane at 4 sites in Sweden.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 14 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 4 sites in Sweden. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Reoperation (time frame: 3 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05267184, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Sep 2026.