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NCT Number: NCT06899711

External Post-Operative Skull Prosthesis to Prevent Sunken Flap Syndrome in 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:

1. Can placing a prosthetic device over patients' skull defects prevent Sunken Flap Syndrome? 2. Can placing a prosthetic device over patients' skull defects decrease healthcare costs? 3. 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

Recruiting

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Key information

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Johns Hopkins Bayview Medical Center, Baltimore, Maryland, United States

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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)

Exclusion criteria

  • 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

Treatment and study plan

External Cranial Prosthesis

Device

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.

Other names: External Skull Prosthesis, External Post-Operative Skull Prosthesis (ExO-Skull)

Primary outcomes

  1. 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.

Secondary outcomes

  1. Ratio of Ipsilateral to Contralateral Middle Cerebral Artery Flow Velocity

    Time frame: Up to 6 months

    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.

  2. Difference in health care utilization for post-craniectomy patients with implementation of ECP

    Time frame: Up to 6 months

    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.

  3. The effect of ECP on neurologic recovery measured by Glascow Coma Scale (GCS)

    Time frame: Up to 6 months

    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.

  4. The effect of ECP on neurologic recovery as measured by confrontational strength testing

    Time frame: Up to 6 months

    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.

  5. The effect of ECP on neurologic recovery as measured by Mini Mental Status Exam

    Time frame: Up to 6 months

    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.

Study contacts

Contact information is provided by the study sponsor or research team.

Fernando Gonzalez, MD

CONTACT

[email protected]

919-886-1166

Joseph M Dardick, MD

CONTACT

[email protected]

314-249-4648

Sponsors and collaborators

Lead sponsor

Johns Hopkins University

Other

Registry information

Official study title

A Prospective Study to Evaluate the Protective Effects of External Cranial Prosthesis on Incidence of Sunken Flap Syndrome in Decompressive Craniectomy Patients

Acronym: ExO-Skull

Important dates

Study start
2025
Primary completion
2028
Study completion
2028
First posted
Mar 28, 2025
Registry last updated
May 11, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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