CraniectomyExO-SkullNCT06899711
External Post-Operative Skull Prosthesis to Prevent Sunken Flap Syndrome in Craniectomy Patients
A study testing External Cranial Prosthesis in people with Craniectomy and Trephined Syndrome, run by Johns Hopkins University at 2 sites in United States.
Trial summary
Patients that undergo decompressive craniectomy are at risk of delayed changes in brain function known as "Sunken Flap Syndrome" or "Syndrome of the Trephined." The goal of this clinical trial is to see if placing a prosthetic over patients' skull defects can prevent "Sunken Flap Syndrome." The main questions are: 1. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Craniectomy, Trephined Syndrome, Traumatic Brain Injury (TBI) Patients
- What is being tested?
- External Cranial Prosthesis
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 72 participants
- Where
- 2 sitesUnited States
- Study dates
- 26 Apr 2025to Apr 2028
- 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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age > 18
- Patients must be admitted to Johns Hopkins Hospital or Johns Hopkins Bayview Medical Center
- Patients must have undergone decompressive hemicraniectomy within 2 weeks of consent for inclusion in the study (before the initial 2 week post-craniectomy assessment)
Who cannot join
- Patients that undergo bilateral decompressive hemicraniectomy
- Patients that undergo suboccipital decompressive craniectomy
- Patients with pre-existing diagnosis of hydrocephalus
- Patients with a ventriculoperitoneal, ventriculoatrial, or other permanent cerebrospinal fluid shunt
- Patients with an open external ventricular drain at the time of their 2 week post-craniectomy assessment
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
United States2 sites, 2 recruiting
- Recruiting
Johns Hopkins Bayview Medical Center
Baltimore, Maryland, 21224
Joseph M Dardick, MD, 314-249-4648, jdardic1@jhmi.edu
Fernando Gonzalez, MD, 919-886-1166, fernando.gonzalez@jhu.edu
- Recruiting
Johns Hopkins Hospital
Baltimore, Maryland, 21287
Joseph M Dardick, MD, 314-249-4648, jdardic1@jhmi.edu
Fernando Gonzalez, MD, 919-886-1166, fernando.gonzalez@jhu.edu
About this study
Official title: A Prospective Study to Evaluate the Protective Effects of External Cranial Prosthesis on Incidence of Sunken Flap Syndrome in Decompressive Craniectomy Patients
Patients that undergo decompressive craniectomy are at risk of delayed changes in brain function known as "Sunken Flap Syndrome" or "Syndrome of the Trephined." The goal of this clinical trial is to see if placing a prosthetic over patients' skull defects can prevent "Sunken Flap Syndrome."
The main questions are:
Read more
- Can placing a prosthetic device over patients' skull defects prevent Sunken Flap Syndrome?
- Can placing a prosthetic device over patients' skull defects decrease healthcare costs?
- Can placing a prosthetic device over patients' skull defects improve recovery and return of brain function after decompressive craniectomy?
Patients that experience traumatic brain injuries, brain bleeds, and large strokes can build up high levels of pressure in the skull. When this pressure can't be controlled with medications, a life-saving surgery called a decompressive hemicraniectomy (DC) is often performed. In this surgery, a large portion of the patient's skull is removed to decrease pressure on the brain and decrease permanent damage.
After this surgery, many patients experience sinking of the brain in the skull as the pressure inside the head improves. The skull normally protects the brain from the outside environment. When large parts of the skull are removed, the brain is not able to regulate itself normally. This can lead to a number of problems, such as headaches, weakness, seizures, and even coma and permanent brain damage. This is referred to as "Sunken Flap Syndrome" (SFS) or "Syndrome of the Trephined" (SoT). After 3-6 months, patients can have the missing skull surgically repaired, which improves and sometimes fixes SFS, but the damage is sometimes too severe to be reversed.
There are reports of patients with SFS treated with custom-made prosthetics that cover the missing piece of skull. In this study, the researchers want to see if wearing a custom-made prosthetic can prevent patients from experiencing SFS. Patients will also receive additional non-invasive measurement to see if the prosthetic can improve brain function and recovery. Finally, the researchers want to know if the prosthetic is cost-effective by decreasing the frequency that patients see doctors or receive care to treat SFS.
Patients or the patient's medical decision makers will be asked if the patient wants to participate in the study after DC. If the patient or decision maker agrees to participate, the patient will be also asked if the patient wants to wear the prosthetic. The prosthetic is made of a common material used in other facial prosthetics. Patients that agree to wear the prosthetic will have a custom plate made for the participant.
All patients will receive the same post-operative care and appointments whether or not the prosthetic is worn. The participant will go to the normally scheduled post-operative doctor's appointments at 2 and 4 weeks after initial DC surgery. Patient's that agree to wear the prosthetic will receive it at the 4-week post-DC appointment. The participant will then be asked to wear it as much as possible, but to let the researchers know if the participant experiences any pain, itching, discomfort or other problems.
All patients will also be seen by the patient's physician before and after and after skull repair. At all appointments, patients will receive non-invasive testing of brain function. Recovery and rate of SFS will be compared between patients that do and do not wear the prosthetic.
Participants will:
- Go to the normally scheduled 2 and 4 week post-DC appointments
- Go to the normally scheduled pre- and post-skull repair appointments
- Receive additional non-invasive brain health testing at each appointment
Participants that agree to wear a prosthetic will:
- Receive the custom prosthetic at the 4-week post-DC appointment
- Wear the prosthetic as much as possible, including at night
- Take a brief survey about the prosthetic at the post-skull repair appointment
- Being tested
- External Cranial Prosthesis
- Keywords
- Syndrome of the Trephined, Sunken Flap Syndrome, Post-Craniectomy Syndrome, Craniectomy
- Medical subject headings
- Brain Injuries, Traumatic, Ischemic Stroke
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
External Cranial ProsthesisDevice
Also called External Skull Prosthesis, External Post-Operative Skull Prosthesis (ExO-Skull)
The external cranial prosthesis is a 3D printed external plate that approximates patients' post-craniectomy skull defect. The prosthesis is made from the same material used in other external Craniofacial prostheses. Patients will be counseled on securing it properly and comfortably on their scalp. Patients will be asked to wear this prosthesis as much as possible until Cranioplasty takes place. After Cranioplasty, the participant will be asked to stop wearing the prosthesis.
| Study group | Role | What they receive |
|---|---|---|
| No Prosthesis | No intervention | Patients that elect not to wear the post-operative skull prosthesis will receive standard-of-care treatment which includes 2-week and 4-week post-operative appointments with neurologic assessments and pre- and post-cranioplasty appointments with neurologic assessments. In addition to their neurologic assessment, the participant will also receive trans-cranial duplex ultrasonography to measure the blood flow velocities in their middle cerebral arteries at each appointment. |
| External Cranial Prosthesis (ECP) | Experimental | Patients that agree to participate in wearing the post-operative skull prosthesis will receive the prosthesis at their 4 week post-operative appointment. At this time, the participant will be asked to wear the prosthesis at all times, as much as the participant is able, and to notify the investigators of any pain, itching, discomfort, or other problems with the prosthesis. These patients will receive a neurologic assessment at this 4-week appointment and will also receive their standard-of-care 2-week post-craniectomy and pre- and post-cranioplasty appointments with neurologic assessments. In addition to these neurologic assessments, the participant will receive trans-cranial duplex ultrasonography to measure the blood flow velocities in their middle cerebral arteries at each appointment. Finally, patients' will receive a survey at their post-cranioplasty appointment with questions regarding their experience with the external cranial prosthesis. Receives: Device: External Cranial Prosthesis |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of Sunken Flap Syndrome
Sunken Flap Syndrome will be defined as development of new neurologic symptoms after acute injury and craniectomy that improve quickly post-cranioplasty (ie. between pre- and post-cranioplasty appointments). Changes will be determined based on Glasgow coma scale, brainstem reflex assessment, confrontational strength testing, and Mini-Mental State Exam testing (MMSE). Patients that have improvement in at least one of these modalities will indicate that the patient suffered from SFS and the reported variable will be "incidence of SFS". The incidence of SFS will be compared between the intervention and non-intervention groups using chi-squared analysis.
Measured: Up to 6 months
Secondary outcomes (5)
Ratio of Ipsilateral to Contralateral Middle Cerebral Artery Flow Velocity
Patients will receive trans-cranial duplex ultrasounds (TCDs) of their middle cerebral arteries (MCAs) at each of their appointments (4-week post-craniectomy and pre- and post-cranioplasty). For each patient that receives TCDs of their MCAs, the investigators will collect the velocity of flow in the MCA ipsilateral to the craniectomy and contralateral to the craniectomy. The investigators will compare the ratio of the ipsilateral and contralateral velocities between the intervention and non-intervention groups via Student's t-test.
Measured: Up to 6 months
Difference in health care utilization for post-craniectomy patients with implementation of ECP
To determine differences in health care utilization between the intervention and non-intervention arms after craniectomy, the investigators will record number of additional hospitalizations, number of days spent inpatient in a hospital facility after discharge from index admission, number of days spent in an ICU after discharge from index admission, number of imaging studies of the brain (CT and MRI) obtained after discharge from index admission, and the number of Emergency Department (ED) visits after discharge from index admission for each patient. These variables will be compared between the two groups via Student's t-test with an alpha of 0.05.
Measured: Up to 6 months
The effect of ECP on neurologic recovery measured by Glascow Coma Scale (GCS)
Patients will receive neurologic assessments at each post-craniectomy appointment including GCS (score range 3-15). The difference in patients' GCS between their 2-week post-craniectomy and 2 week post-cranioplasty assessments will be compared between the intervention and non-intervention group via Student's T-test with an alpha of 0.05. In general, a higher GCS score less likelihood of brain injury, better outcome.
Measured: Up to 6 months
The effect of ECP on neurologic recovery as measured by confrontational strength testing
Patients will receive neurologic assessments at each post-craniectomy appointment including confrontational strength testing. Strength is measured on a scale from 0-5 with 5 indicating full strength. The difference in their performance at the 2-week post-craniectomy and 2 week post-cranioplasty assessments will be compared between the intervention and non-intervention groups via Student's T-test with an alpha of 0.05.
Measured: Up to 6 months
The effect of ECP on neurologic recovery as measured by Mini Mental Status Exam
Patients will receive neurologic assessments at each post-craniectomy appointment including Mini Mental Status Exam. This is measured on a scale from 0 to 30 with lower scores indicating more cognitive impairment. The difference in patients' MMSE score at the 2-week post-craniectomy and 2 week post-cranioplasty assessments will be compared between the intervention and non-intervention groups via Student's T-test with an alpha of 0.05.
Measured: Up to 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Mar 2025
- Study start26 Apr 2025
- Primary completionApr 2028 (estimated)
- Study completionApr 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for CraniectomyStudies of the same condition, open and under way.
- More trials run by Johns Hopkins UniversityThe 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
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 72 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Johns Hopkins University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Joseph M Dardick, MD, Principal investigator, Johns Hopkins Medical InstituteFernando Gonzalez, MD, Principal investigator, Johns Hopkins University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06899711
- Sponsor's protocol ID
- IRB00475054
- Acronym
- ExO-Skull
- Status last verified
- May 2026
- First submitted
- 21 Mar 2025
- Last updated
- 11 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 11 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Prospective Study to Evaluate the Protective Effects of External Cranial Prosthesis on Incidence of Sunken Flap Syndrome in Decompressive Craniectomy Patients
- ClinicalTrials.gov ID
- NCT06899711
- Acronym / sponsor ID
- ExO-Skull / IRB00475054
- Keywords
- Syndrome of the Trephined, Sunken Flap Syndrome, Post-Craniectomy Syndrome, Craniectomy
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 72 participants (estimated)
- Lead sponsor
- Johns Hopkins UniversityUniversity, hospital or other
- Study start
- 26 Apr 2025 (actual)
- Primary completion
- Apr 2028 (estimated)
- Study completion
- Apr 2028 (estimated)
- First posted
- 28 Mar 2025 (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.
Patients that undergo decompressive craniectomy are at risk of delayed changes in brain function known as "Sunken Flap Syndrome" or "Syndrome of the Trephined." The goal of this clinical trial is to see if placing a prosthetic over patients' skull defects can prevent "Sunken Flap Syndrome."
The main questions are:
- Can placing a prosthetic device over patients' skull defects prevent Sunken Flap Syndrome?
- Can placing a prosthetic device over patients' skull defects decrease healthcare costs?
- Can placing a prosthetic device over patients' skull defects improve recovery and return of brain function after decompressive craniectomy?
Patients that experience traumatic brain injuries, brain bleeds, and large strokes can build up high levels of pressure in the skull. When this pressure can't be controlled with medications, a life-saving surgery called a decompressive hemicraniectomy (DC) is often performed. In this surgery, a large portion of the patient's skull is removed to decrease pressure on the brain and decrease permanent damage.
After this surgery, many patients experience sinking of the brain in the skull as the pressure inside the head improves. The skull normally protects the brain from the outside environment. When large parts of the skull are removed, the brain is not able to regulate itself normally. This can lead to a number of problems, such as headaches, weakness, seizures, and even coma and permanent brain damage. This is referred to as "Sunken Flap Syndrome" (SFS) or "Syndrome of the Trephined" (SoT). After 3-6 months, patients can have the missing skull surgically repaired, which improves and sometimes fixes SFS, but the damage is sometimes too severe to be reversed.
There are reports of patients with SFS treated with custom-made prosthetics that cover the missing piece of skull. In this study, the researchers want to see if wearing a custom-made prosthetic can prevent patients from experiencing SFS. Patients will also receive additional non-invasive measurement to see if the prosthetic can improve brain function and recovery. Finally, the researchers want to know if the prosthetic is cost-effective by decreasing the frequency that patients see doctors or receive care to treat SFS.
Patients or the patient's medical decision makers will be asked if the patient wants to participate in the study after DC. If the patient or decision maker agrees to participate, the patient will be also asked if the patient wants to wear the prosthetic. The prosthetic is made of a common material used in other facial prosthetics. Patients that agree to wear the prosthetic will have a custom plate made for the participant.
All patients will receive the same post-operative care and appointments whether or not the prosthetic is worn. The participant will go to the normally scheduled post-operative doctor's appointments at 2 and 4 weeks after initial DC surgery. Patient's that agree to wear the prosthetic will receive it at the 4-week post-DC appointment. The participant will then be asked to wear it as much as possible, but to let the researchers know if the participant experiences any pain, itching, discomfort or other problems.
All patients will also be seen by the patient's physician before and after and after skull repair. At all appointments, patients will receive non-invasive testing of brain function. Recovery and rate of SFS will be compared between patients that do and do not wear the prosthetic.
Participants will:
- Go to the normally scheduled 2 and 4 week post-DC appointments
- Go to the normally scheduled pre- and post-skull repair appointments
- Receive additional non-invasive brain health testing at each appointment
Participants that agree to wear a prosthetic will:
- Receive the custom prosthetic at the 4-week post-DC appointment
- Wear the prosthetic as much as possible, including at night
- Take a brief survey about the prosthetic at the post-skull repair appointment
Study design
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| No Prosthesis | No intervention | –Patients that elect not to wear the post-operative skull prosthesis will receive standard-of-care treatment which includes 2-week and 4-week post-operative appointments with neurologic assessments and pre- and post-cranioplasty appointments with neurologic assessments. In addition to their neurologic assessment, the participant will also receive trans-cranial duplex ultrasonography to measure the blood flow velocities in their middle cerebral arteries at each appointment. |
| External Cranial Prosthesis (ECP) | Experimental | Device: External Cranial ProsthesisPatients that agree to participate in wearing the post-operative skull prosthesis will receive the prosthesis at their 4 week post-operative appointment. At this time, the participant will be asked to wear the prosthesis at all times, as much as the participant is able, and to notify the investigators of any pain, itching, discomfort, or other problems with the prosthesis. These patients will receive a neurologic assessment at this 4-week appointment and will also receive their standard-of-care 2-week post-craniectomy and pre- and post-cranioplasty appointments with neurologic assessments. In addition to these neurologic assessments, the participant will receive trans-cranial duplex ultrasonography to measure the blood flow velocities in their middle cerebral arteries at each appointment. Finally, patients' will receive a survey at their post-cranioplasty appointment with questions regarding their experience with the external cranial prosthesis. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Age > 18
- Patients must be admitted to Johns Hopkins Hospital or Johns Hopkins Bayview Medical Center
- Patients must have undergone decompressive hemicraniectomy within 2 weeks of consent for inclusion in the study (before the initial 2 week post-craniectomy assessment)
Key exclusion criteria (5 listed)
- Patients that undergo bilateral decompressive hemicraniectomy
- Patients that undergo suboccipital decompressive craniectomy
- Patients with pre-existing diagnosis of hydrocephalus
- Patients with a ventriculoperitoneal, ventriculoatrial, or other permanent cerebrospinal fluid shunt
- Patients with an open external ventricular drain at the time of their 2 week post-craniectomy assessment
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 |
|---|---|---|
| External Cranial ProsthesisAlso: External Skull Prosthesis, External Post-Operative Skull Prosthesis (ExO-Skull)The external cranial prosthesis is a 3D printed external plate that approximates patients' post-craniectomy skull defect. The prosthesis is made from the same material used in other external Craniofacial prostheses. Patients will be counseled on securing it properly and comfortably on their scalp. Patients will be asked to wear this prosthesis as much as possible until Cranioplasty takes place. After Cranioplasty, the participant will be asked to stop wearing the prosthesis. | Device | External Cranial Prosthesis (ECP) |
Primary outcome
Incidence of Sunken Flap Syndrome
Time frame: Up to 6 months
Sunken Flap Syndrome will be defined as development of new neurologic symptoms after acute injury and craniectomy that improve quickly post-cranioplasty (ie. between pre- and post-cranioplasty appointments). Changes will be determined based on Glasgow coma scale, brainstem reflex assessment, confrontational strength testing, and Mini-Mental State Exam testing (MMSE). Patients that have improvement in at least one of these modalities will indicate that the patient suffered from SFS and the reported variable will be "incidence of SFS". The incidence of SFS will be compared between the intervention and non-intervention groups using chi-squared analysis.
5 secondary outcomes
Ratio of Ipsilateral to Contralateral Middle Cerebral Artery Flow Velocity
Time frame: Up to 6 months
Difference in health care utilization for post-craniectomy patients with implementation of ECP
Time frame: Up to 6 months
The effect of ECP on neurologic recovery measured by Glascow Coma Scale (GCS)
Time frame: Up to 6 months
The effect of ECP on neurologic recovery as measured by confrontational strength testing
Time frame: Up to 6 months
The effect of ECP on neurologic recovery as measured by Mini Mental Status Exam
Time frame: Up to 6 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 11 May 2026.
- 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.
Joseph M Dardick, MD principal investigator
Johns Hopkins Medical Institute
Fernando Gonzalez, MD principal investigator
Johns Hopkins University
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing External Cranial Prosthesis in people with Craniectomy and Trephined Syndrome, run by Johns Hopkins University at 2 sites in United States.
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 3 inclusion and 5 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: looking for participants now, as of the sponsor's last update on 11 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. 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?
Contact Joseph M Dardick, MD (314-249-4648, jdardic1@jhmi.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of Sunken Flap Syndrome (time frame: Up to 6 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 11 May 2026.