Effectiveness of Surgical Procedures for Acute Cranial Expansion in Traumatic Brain Injury

A Comparative-effectiveness Study on Expansion Craniotomy Versus Decompressive Craniectomy for Surgical Management of Traumatic Brain Injury in Patients With Intracranial Compartment Syndrome

Traumatic brain injury (TBI) patients often exhibit an increase in their intracranial volume due to blood collection or brain tissue edema. When the volume of any intracranial compartment exceeds a critical threshold, the compensatory mechanisms become exhausted, compromising intracranial compliance and blood supply, which leads to intracranial compartment syndrome (ICCS). The presence of this condition exacerbates brain damage through secondary injury. When less invasive measures to counteract ICCS prove to be insufficient, cranial decompression is recommended, with decompressive craniectomy (DC) being the preferred technique.

Although its effectiveness has been demonstrated, DC is also associated with an incidence of complications. Expansive craniotomy (EC) has been proposed as an alternative that can increase the benefits of cranial decompression provided by DC while reducing the associated complications. This observational study will compare the functional outcomes and complications of patients managed by DC and EC.

In cranial decompression, a cranial vault bone graft is removed and left out to be stored in a bone bank or an abdominal pouch generated during the surgery. In the cranial expansion, the cranial vault bone graft is fixed in an elevated position 1 - 1.5 cm above the external cranial table and fixed by 3-5 metallic plates placed during surgery.

Participants' progress will be observed during their hospital stay and assessed for 1 year through structured telephone follow-ups. The main outcomes will include functional recovery and the rate of complications such as operative site infections, and/or reinterventions. By comparing these two surgical methods, the study seeks to determine whether the expansion craniotomy improves outcomes for TBI patients while maintaining or enhancing the safety and reliability of the cranial decompression procedure.

Currently, decompressive craniectomy (DC) is the most frequently used technique. The Brain Trauma Foundation's current guidelines discuss it and describe the actual evidence. This technique will serve as a comparator for expansion craniotomy (EC). The allocation of patients to the intervention will be based on the clinical criteria of the treating neurosurgeon as long as the patients meet the inclusion criteria and do not present any exclusion criteria.

Neurosurgeons will describe the reason(s) why one technique or another was indicated and why the surgical approach was selected. The EC technique is standardized and will be performed through a retro-auricular "C-shape" incision and executing a 15x15 cm craniotomy with a "C-shape" durotomy. Dural closure will be at the discretion of the surgeon and the availability of resources, including duroplasty with aponeurotic galea, a suturable dural patch, a non-suturable dural patch, or simply a superficial dural cover with hemostatic materials like Surgicel® or Gelfoam®.

The expansion craniotomy will be finished with a cranioplasty using specific mini plates (3-5 "Rialto" plates) for bone fixation.

There are multiple techniques for DC. The elected technique will be at the discretion of the treating neurosurgeon, but only frontal-parietal-temporal DC will be considered. The removed bone flap may be stored in an abdominal pouch in the right or left upper abdominal quadrants or by freezing in a bone or blood bank freezer. Patients who receive an EC may subsequently be taken to DC if the expected improvement is not achieved with the intervention, according to the postsurgical images and invasive and noninvasive neuromonitoring, based on the criteria of the treating neurosurgeon. If this happens, the treating neurosurgeon must specify why they opted for the procedure. On the other hand, the intervention cannot be changed in patients taken to DC once the surgery is completed since the bone would have already been removed and stored.

Inclusion Criteria:

1. TBI patients arriving at the emergency room in the first 24 hours following trauma.
2. Abnormal computed tomography (CT), with a primary injury including any epidural, intracerebral, or subdural collection with a midline shift >3mm and any basal cistern compression with at least 2 abnormal findings in the initial evaluation at the emergency room (including optic nerve ultrasound > 6mm at the same side of the CT´s primary injury or and/or an abnormal pupillometry with a reduced (Maximum Contraction Velocity) MCV in the pupil of the same side of the CT´s primary injury, or/and a Trans- Cranial Doppler (TCD) with Pulsatility Index (PI) > 1.3 and/or Middle Cerebral Artery - Diastolic Velocity (MCA-DV) < 20cm/seg on the same side of the CT´s primary injury or/and an Intracranial Pressure Pulse Wave (ICPPW) ICPPW2 > ICPPW1 waveform pattern in the same side of the CT´s primary injury).
3. Age 18 to 70 years old.
4. Patients with or without polytrauma with survival expectancy >24 hours.
5. Cranial decompression or cranial expansion surgical procedures less than 24 hours after the trauma.

Exclusion Criteria:

1. TBI patients arriving at the emergency room after 24 hours following trauma.
2. Normal CT scan at the emergency room.
3. Abnormal CT scan at the emergency room with any primary injury and midline shift less than 3mm or without basal cistern compression and with normal values in at least two different modalities of assessing ICCS (pupillometry, optic nerve sheath ultrasound, transcranial Doppler and/or non-invasive ICP waveform analyzer).
4. Age less than 18 or more than 70 years old.
5. Polytrauma or massive brain injury with survival expectancy < 24 hours.
6. Cranial decompression or cranial expansion surgical procedures performed > 24 hours after the trauma.