SKULL FRACTURES

A.

Linear skull fractures are most common and typically occur over the lateral convexities of the skull. The squamous portion of the temporal bone in this region is thin and closely associated with the middle meningeal artery. Fractures in this area can tear the artery, which is the most common cause for epidural hematoma.

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For most skull fractures, it is not the fracture but rather the underlying blood clot or brain contusion that raises concern. Because these associated lesions are best detected with CT and are not recognized with plain skull x-rays, a CT of the head is the diagnostic study of choice for patients suspected of having a skull fracture.

B. Depressed skull fractures

The surgical elevation and repair of these fractures will not lead to a change in associated neurologic deficit or a decrease the risk for subsequent seizures. These fractures may be open (associated with an overlying scalp laceration) or closed. Indications for surgical repair of depressed skull fractures are evidence of CSF leak, cosmetic deformity, or contaminated bone or scalp fragments pushed into the brain. In addition, when a dural tear is suspected— usually indicated by the bone being depressed beyond the inner table—then repair should be considered. Other treatment includes:

• Broad-spectrum antibiotics for 7 to 14 days if the wounds are contaminated or the fracture involves a facial sinus
• Prophylactic anticonvulsant therapy for 7 days

C.

Basilar skull fractures which occur most commonly through the floor of the anterior cranial fossa, can disrupt the ethmoid bones and lead to CSF leak through the nose (rhinorrhea). Fractures also can occur through the petrous bones posteriorly, leading to CSF drainage through the ear (otorrhea). Cranial nerve injuries are commonly associated with posterior basilar skull fractures, and findings should be sought on clinical examination.

• The primary concern with basilar skull fractures is associated CSF leak and risk of meningitis.
• Prophylactic antibiotic treatment is not recommended. Several investigations have found that morbidity is increased with prophylactic antibiotics because of selection of more virulent organisms.
• Attempts to stop the leak should begin with elevation of the head of the bed to 60 degrees. If the leak does not stop within 6 to 8 hours, a lumbar CSF drainage catheter should be placed (provided there are no contraindications on CT such as edema or a mass lesion), and 50 to 100 mL of CSF should be drained every 8 hours. If this fails to stop the leak within 72 hours, the patient should be taken to surgery for repair of the dural laceration. When a patient deteriorates while undergoing lumbar CSF drainage it may be associated with overdrainage or meningitis. The lumbar drain should be closed if this happens.