Craniocerebral trauma can involve injury to the scalp, skull meninges, or brain. Most are not life threatening, though lifelong sequelae are not uncommon. Fifty to 90 percent of TBI-related hospital admissions are for mild injuries, while 10–30% are for moderate injuries and 5–25% for severe ones. These numbers must be taken with caution, however, as the definition of “mild” varies considerably.
The heterogeneous and dynamic nature of craniocerebral trauma makes it impossible to address treatment options as a strict algorithm. However, we can address the two major issues that, if left untreated, can lead to severe disability — hemodynamic and neurologic instability.
Signs should be treated with rapid and aggressive volume resuscitation. Crystalloid solutions such as 0.9% ssodium chloride (NaCl) solution or lactated Ringer’s are the fluid of choice. The author prefers the former to keep the patient mildly hypernatremic (serum sodium 146–148 mmoles/L). This both raises the seizure threshold and helps control intracranial hypertension. Red blood cells (O-negative or type-specific) and whole blood infusions should be given if the patient has suffered significant blood loss. At least four units of blood products should be ready and available for immediate use during the initial resuscitation period. Trauma patients also commonly develop coagulopathies such as diffuse intravascular coagulopathy, which must be treated aggressively with frozen plasma. Pressor agents such as Neo-Synephrine, dopamine, or norepinephrine must be used judiciously and never before the patient’s intravascular volume has been repleted.
In addition to hemodynamic support, the patient’s airway ventilation and oxygenation must be rapidly assessed and secured. In some cases, this involves endotracheal intubation or, if necessary, placement of a transcutaneous tracheal airway (via cricothyrotomy or tracheotomy). The term “in-line traction” is often used to describe the maneuver used to maintain cervical stability during intubation. This is somewhat of a misnomer, since the spine is rarely placed in traction per se. Essentially, all that is needed is to maintain normal cervical alignment during intubation.
Neurologic instability is almost always the result of intracranial hypertension. Seizures, drugs, and systemic hypotension can also present as neurologic instability.
Patients with craniocerebral trauma are at risk for developing seizures. Some patients present actively seizing and should be treated with anticonvulsant medications—phenytoin (or fosphenytoin) 15–20 mg/kg intravenous (IV) load, followed by a maintenance dose of 300–400 mg/d. The advantage of fosphenytoin is that it can be infused more quickly than phenytoin without the risk of inducing hypotension—it is, however, considerably more expensive. Status epilepticus should be treated with benzodiazepines such as Ativan or Valium. Patients with intracranial pathology such as intraparenchymal contusions, subdural hematomas, or large epidural hematomas should also be given anticonvulsants, as they are at risk for developing posttraumatic seizures. In the absence of seizures, anticonvulsants can be discontinued at 7 days. This approach decreases the incidence of early posttraumatic seizures yet minimizes the patient’s exposure to anticonvulsants. If the patient develops seizures after anticonvulsants are stopped, these should be reinstituted. Patients who are chronic alcoholics are also at risk for developing alcohol-withdrawal seizures and should be treated primarily with benzodiazepines such as chlordiazepoxide (if taking oral medications) or diazepam until they have completed their withdrawal—usually in 5–7 days.
The surgical treatment of trauma is fairly straightforward—the most difficult aspect, really, is not technical, but knowing when to operate and when not to. The actual surgical approach depends on the location and effects of the pathology. As such we will discuss the treatment of epidural hematomas, subdural hematomas, intraparenchymal contusions, open skull fractures, and scalp lacerations separately. All trauma patients get a complete head shave at our institution prior to incision and if time permits (and skull integrity permits) are put in three-point fixation.
Epidural hematomas almost always underlie a skull fracture. The most common location is the temporal fossa, since the temporal squamosa is the thinnest part of the cranial vault and the most likely to fracture and can easily lacerate the underlying middle meningeal artery. Other less common locations include the frontal and parietal convexity as well as the occipital and infratentorial compartments. Occasionally, a skull fracture will cross a venous sinus—the superior sagittal sinus and transverse sinuses being the most susceptible—causing the formation of a venous epidural hematoma.
The general approach is to make a curvilinear scalp incision to expose the entire skull overlying the hematoma (or as much as possible). Usually, one encounters a skull fracture on turning the skin flap. If the temporalis muscle is overlying the site, this should also be reflected inferiorly, leaving a thin rim of temporalis fascia attached to the superior temporal line (if possible) to which the muscle can be attached at the end of surgery. Once the bone is exposed, a single burr hole is made with a cutting burr somewhere near the edge of the underlying hematoma. The cranial flap can then be turned using the drill’s foot-plate attachment. The hematoma is then evacuated, any dural bleeding stopped, and the dura secured to the craniotomy edge using 4-0 braided nylon sutures. The authors usually make a small dural incision to inspect the subdural space to rule out the presence of a coincident subdural hematoma. Once hemostasis is ensured, the bone flap is reattached using three “dog-bone” titanium plates at the edge of the craniectomy. The musculocutaneous flap is then closed using 2-0 Vicryl sutures for the galeal layer and staples for the skin. An ICP monitor is frequently placed at this time, prior to transport to the ICU.
A special note about venous epidural hematoma should be offered: These injuries can cause massive exsanguination in a very short period of time. What makes them so difficult is the state of the underlying venous dural sinus. Exposing the sinus is very difficult as this is usually criss-crossed by multiple comminuted scull fractures that make localization of the dural sinus tear difficult. Massive blood loss occurring at the time of opening makes visibility even more difficult. The key is to run the craniotomy parallel to and just lateral to the sinus (and, if possible, both sides) and place multiple dural tack-up stitches along its edge. Trying to expose the entire sinus is usually futile and fatal.
The approach to subdural hematoma is really no different than that for epidural hematoma except that the craniotomy is usually much larger and the dura is opened. The scalp incision is usually a very large curvilinear incision beginning at the hairline in the midline and continuing along the midline to approximately lambda. From here, the incision continues parallel to the lambdoid suture to the level of the asterion and then continues anteriorly just above the ear and curves anterior to the ear to end 1 cm inferior to the zygoma’s root. The temporalis muscle is removed as above, but no time is wasted in preserving the fascial attachment to the superior temporal line. This distinction is in contrast to the approach to epidural hematoma since the author often does not replace the bone flap following the evacuation of the hematoma because the brain is much more likely to swell significantly, causing ICP management problems. In any case, the skull is removed as described above but hugging the periphery of the skin incision and extending the craniotomy down to the frontal floor and pole and the temporal floor and pterion. Though this seems like a lot of surgery, it rarely takes more than 5 minutes to complete the craniotomy from the time of first skin incision. Once the skull is off, the dura is rapidly and widely opened using tenotomy scissors. At this point, the hematoma is evacuated.
Subdural hematomas result from tearing of cortical draining veins. These typically drain into six areas—the superior sagittal sinus at
the frontal pole,
along the frontoparietal junction
the occipital pole,
the sphenoparietal sinus at the temporal pole,
the transverse sigmoid junction,
along the superior petrosal sinus.
These areas should be inspected to ensure that any active bleeding has stopped. Once hemostasis is ensured, a ventriculostomy is passed through the exposed frontal lobe into the lateral ventricle. A subdural drain is placed and both catheters are tunneled through the skin outside the musculocutaneous flap. The brain is then covered with Gelfoam and the skin flap closed with 2-0 Vicryl. If the bone is replaced, it is done so as described above.
The approach to intraparenchymal contusion depends on the presence of an subdural hematoma. In the absence of the hematoma and significant global cerebral swelling, an approach akin to that of epidural hematoma is used. If not, the subdural hematoma approach is used. Once the brain is exposed, a small cortical incision is made where the contusion is closest to the surface of the brain—avoiding eloquent areas such as the primary motor cortex. Once the contusion is encountered, it usually delivers itself with minimal effort. Hemostasis is ensured and the wound closed as above.
Open Skull Fractures and Scalp Lacerations
These can be discussed together as their surgical approach is similar. The main surgical objective is to clean the area to minimize the risk of infection and optimize wound closure. In the case of skull fractures, attention must be paid to the possibility of underlying dural lacerations or hematomas. If either is present, a more extensive exploration may be necessary. Much emphasis has been placed on the need for meticulous dural repair. In the author’s opinion, this is not necessary as long as the area has been cleaned and debrided well. Experience from treatment of penetrating injuries has shown that even these do not require aggressive debridement and dural repair. Scalp wounds require mainly that devitalized tissue be removed, wound edges cleaned, and the galea be closed as completely as possible.