| Print Date: | May 23, 2013, 2:04 pm |
| Title | 1. Depressed compound temporoparietal skull fracture 2. Hemorrhagic / nonhemorrhagic contusions at the depressed fracture margins 3. Basal skull fracture (sphenoid and ethmoid sinuses) 4. Chiasmatic sulcus/tuberculum sellae fractures with optic chiasm injury 5. Small left convexity subdural hematoma |
| Text | Depressed skull fractures typically occur when objects with a large amount of kinetic energy (e.g., baseball bat, hammer, rock) make contact with the skull over a fairly small area. Energy from the object is locally dissipated to the calvarium resulting in a depressed skull fracture. Depression occurs when the traumatic force overcomes the resisting elastic recoil of the bony calvarium. A variably sized area of bone fails to rebound after the blow. Depression of the fracture will persist when there is entrapment of bone at the peripheral fracture margins or fragmentation of the depressed portion of the skull. The area and depth of calvarial depression will vary depending on the size, mass, and velocity of the object which strikes the head. Depressed skull fractures are classified as open (compound) when the scalp over the area of injury is lacerated and closed (simple) when the scalp is still intact. Although linear fractures are most commonly of the closed type, depressed fractures are usually (85%) open.
Depressed skull fractures may or may not be associated with injury to the underlying brain. Quite importantly, 50% of patients with compound depressed skull fractures do not have associated underlying brain injury of a degree sufficient to produce unconsciousness. Even with marked depression of fragments, intracranial injury may be surprisingly minimal. Nevertheless, there is a significant incidence of intracranial injury in patients with depressed skull fractures; contusions (26%), dural sinus injury (12%), intracranial hematoma (5-7%), secondary infections (3-10%), persistent neurologic deficits (11%), posttraumatic epilepsy (7-10%), and death (11%). It is somewhat controversial among neurosurgeons as to which depressed skull fractures are "significant" and require elevation and/or debridement. The following depressed fractures are generally considered significant, as they may alter patient treatment: 1. those located over the motor strip, 2. those overlying a dural sinus, 3. fractures whose depressed margins lie beneath the adjacent skull, 4. open fractures with dural tears and pneumocephalus, and 5. open fractures with intracranial foreign bodies. In patients with depressed open skull fractures, most neurosurgeons choose to promptly debride the soft tissues and elevate the fragments, since these patients are at significant risk for CNS infections. Most do not elevate closed depressed fractures in conscious patients without any neurologic deficits, unless they cause cosmetic deformity. Open depressed fractures overlying dural sinuses are particularly problematic. Debridement and elevation are difficult and surgery carries a risk of massive uncontrollable hemorrhage. As seen in this case, MRI is significantly more sensitive than CT for visualizing nonhemorrhagic contusions adjacent to depressed skull fractures. CT is more beneficial, however, for defining fractures. Cerebral angiography is essential for excluding a dural sinus tear caused by a depressed skull fracture. |
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| Contributor | Neuroradiology Learning File - © ACR (ACR Learning File®) |
| Author | Lindell R. Gentry, MD |
| Peer Reviewer | James G. Smirniotopoulos, M.D. (Uniformed Services University) |
| Record Number | : 1545 |
| Created | 2001-03-27 13:04:10-05 |
| Modified | 2001-08-07 22:11:00-04 |
| Category: | Trauma |
| Location: | Brain and Neuro |
| Sublocation: | None Selected |
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