INDICATIONS TO PERFORM CRANIAL PROCEDURES IN AUSTERE SETTING

The decision to perform a neurosurgical intervention in an austere location is best made with the telemedicine support of a neurosurgeon.

Telemedicine consult may be obtained from the closest neurosurgeon in the evacuation chain. In addition, worldwide neurosurgery consultation is available at Advanced Virtual Support for Operational Forces (ADVISOR): Synchronous, 24/7 provider to provider consultation service for operational forces (833) 238-7756 or DSN (312) 429-9089

If CT scan is available, obtaining a stat CT head (without contrast) will greatly facilitate the appropriate treatment and intervention.

When a CT scan is not available, there is a high risk that procedures may be performed without correct localization of pathology. It is therefore necessary to make an accurate diagnosis, appropriately resuscitate, and exhaust all medical interventions prior to performing a procedure in this environment. Regardless of whether a CT scan is available, the indications for surgical intervention are clinical.

When To Perform Cranial Procedures

Perform only:

- After teleconsultation with neurosurgery
- Evacuation to a neurosurgeon is not available within approximately 5 hours of severe injury (see below)2,11
- Surgeon training and resources are adequate. See Appendix A (Training) and Appendix B (Resources).

Indications:

- Severe closed supratentorial brain injury with a presenting Glasgow Coma Scale (GCS) ≤ 8 AND:
  - Lateralizing cortical dysfunction such as unilateral dilated pupil or hemiparesis AND
  - Hemodynamic dysfunction indicative of impending herniation: hypertension, bradycardia, and respiratory variation (Cushing’s reflex) AND
  - Failure of maximal critical care management to stabilize the patient.2,10 This may manifest by the persistence of the above two findings despite maximal critical care interventions (Tier 1-3 interventions – see Traumatic Brain Injury and Neurosurgery in the Deployed Environment CPG), or the occurrence of a new or worsening lateralizing cortical finding (hemiparesis, rapidly expanding pupil) and/or further decline in GCS off of sedation

When Not To Perform Cranial Procedures

- Clinical condition and neurologic status stabilized or improved with aggressive medical management.
- Surgeon and resources are not adequate. See Appendix A (Training) and Appendix B (Resources).
- The patient has a post-resuscitation GCS = 3 with bilateral fixed and dilated pupils. This is non-survivable. Refer to Catastrophic Non-Survivable Brain Injury CPG for supportive care.12
- Imaging evaluation demonstrating catastrophic injury with poor clinical prognosis (consult with neurosurgeon, Example: missile crossing zona fatalis.)13

Checklist/Procedures For Craniectomy

1. Obtain stat non-contrast head CT (if available).
2. Establish teleconsultation with neurosurgeon. Video consultation is preferred. If unable to communicate with a neurosurgeon, recommend a multi-disciplinary discussion which includes the local command authority prior to proceeding.
3. Make every effort to evacuate the patient to a facility where neurosurgery is available within approximately 5 hours.
4. Assess indications for craniectomy.
5. Assess availability of follow-on care.
6. Ensure that maximal medical/critical care management and resuscitation of the patient’s intracranial condition has occurred. This should include appropriate blood component resuscitation, hypertonic saline, anticonvulsant, sedation, etc. in accordance with the Traumatic Brain Injury Management and Neurosurgery in the Deployed Environment CPG.2
7. Ensure that the surgeon training and the facility resources are adequate.
8. If the above indications are met, then, in consultation with a neurosurgeon (when possible), consider intervention as follows. (Note: Review Emergency War Surgery Manual for further details.4)

Cranial Procedures For Closed Head Injury14, 15

*If no CT scan is available, an accurate neurological examination must be obtained for the purposes of localizing the lesion. A skull X-ray may improve localization in cases of skull fracture or penetrating brain injury.*

*Proper positioning of the patient is essential.*

1. Avoid any compression of the neck to assure unhindered jugular venous outflow. Temporary removal of cervical collar is recommended as well as the use of a generous shoulder bump to allow semi-lateral positioning without the need for severe head rotation.
2. The head should be positioned slightly higher than the chest to reduce venous congestion and decrease bleeding.
3. Rotate the head 30-40° off midline such that the side being operated on is highest.
4. Mark the midline of the scalp, as well as the location of anticipated burr hole and craniotomy incisions, prior to draping the head. The planned craniotomy should encompass any penetrating injury, if present. It is critical that the planned hemi-craniotomy/craniectomy should achieve adequate dimensions of decompression (15cm AP length, 12cm width, taken to the floor of the middle fossa to decompress the temporal lobe). Equally important is avoidance of iatrogenic superior sagittal sinus injury through inadvertent craniectomy too close to the midline.
5. A single myocutaneous flap should be elevated forward from the cranial surface using cautery and periosteal elevators. Multiple incisions have been described to achieve adequate exposure for optimal cranial decompression. The temporalis is divided superior to the root of the zygoma and dissected anteriorly with its pedicle deep to the zygoma. The flap is secured with skin hooks or suture, permitting access to the middle cranial fossa. Scalp hemorrhage can be extreme and should be meticulously controlled with Raney clips, suture, cautery, or hemostats.

*If pre-operative imaging is not available, exploratory burr holes should be made over the frontal, temporal and parietal convexities using the cranial drill for the purposes of identifying a hematoma. Electric drills are carried by some Role 2 teams. Manual drill/saw with Hudson Brace and Gigli saw is an extremely time-consuming and energy intensive process*

1. The dura can be opened carefully through the burr hole following cauterization if hemorrhage is subdural.
2. If there is evidence of acute epidural/subdural bleeding (bleeding is not controlled), or if the hematoma is not fully evacuated, a craniectomy should be performed.
3. Burr holes alone are unlikely to be helpful in the setting of severe TBI caused by penetrating trauma, acute subdural hematoma, or an acute epidural hematoma; while they are not therapeutic, they are diagnostic for localization of the bleed in the absence of preoperative imaging. Craniectomies should NOT be performed if no subdural or epidural hematoma is encountered, unless there is external evidence of ipsilateral penetrating injury.

*Once the decision to proceed with craniectomy is made, the dura must be carefully separated from the inner table of the skull (Penfield 1-3 instruments) and the burr holes connected with the Gigli saw or electric drill using either a side-cutting bit or a “matchstick” bit.*

1. An appropriately sized hemi-craniectomy is usually at least 15cm long in the sagittal plane and 12cm in height in the coronal plane, a smaller craniectomy is not advisable in the far-forward setting.
2. Take care to stay >2.5cm from midline in-order-to avoid injury to the superior sagittal sinus.
3. If the hematoma is epidural, it must be evacuated and the bleeding source cauterized.
4. If subdural, the dura must be opened, the hematoma evacuated, and if visible, the bleeding source cauterized.
5. DO NOT replace the bone. For U.S. Service Members, the bone should be discarded with planned future cranioplasty with custom implant.
6. If not visible, do not search for a hemorrhage source in order to minimize risk of further injury.
7. If subdural pathology, do not close the dura. The dura may be loosely reapproximated over the cerebral hemisphere. Dural allograft (e.g., Duragen), if available, should be placed over the decompressed cerebral hemisphere for improved cerebrospinal fluid (CSF) control and to assist with future cranioplasty. Alternative hemostatic agents (e.g., Gelfoam, Surgicel) or pericranium autograft can be used to create a barrier between cerebral cortex and scalp.
8. An intracranial monitor (external ventricular drain (EVD) or parenchymal intracranial pressure (ICP) monitor) should be placed if available and the surgeon is adequately trained to perform the procedure. EVD is preferred as it is both a diagnostic and therapeutic device.
9. In all circumstances, the scalp must be closed (interrupted 2-0 Vicryl to reapproximate Temporalis fascia, interrupted 2-0 Vicryl to close galea, running staple line for skin).

*If the brain herniates rapidly after dural opening, close the scalp immediately due to risk of cyclical and catastrophic extracranial herniation, which is associated with a high mortality *

Cranial Procedures For Penetrating Head Injury

Penetrating brain injury is one of the most challenging indications for cranial procedures performed by neurosurgeons.

1. Exploration without teleconsultation from a neurosurgeon is NOT
2. There is often deep and uncontrollable bleeding that may not be evident on the cortical surface.
3. Surgical exploration below the surface of the brain is NOT
4. Surgical intervention should be limited to removing bone, opening the dura, controlling bleeding, and closing the skin rapidly.

If cranial contents are herniated from either the entry or exit wound, allow this to continue. Do not close the wound. Recommend coverage with a loose, clean dressing (Kerlix soaked in saline) and initiate and maintain IV antibiotic coverage with central nervous system penetration.

Adequately resuscitate as necessary, and transport at the soonest opportunity.

If evacuation to a higher role of care is not possible, recognize that intervention in this case may be futile.