SKULL FRACTURES and head injuries...pptx

SKULL FRACTURESSKULL FRACTURES for undergrads

1. Acute traumatic conditions - head injuries

2. QUICK ANATOMY 3 layers :- Outer table Diploe Inner table Parts without diploe prone to fracture -- squamous temporal bone -- foramen magnum, skull base, cribiform plates, orbital roofs.

3. introduction Skull fractures can be caused by blunt or penetrating injury and frequently tear the underlying meninges if depressed. Anterior cranial fossa fractures are frequently associated with a CSF leak, especially when comminuted or oblique . Fractures that traverse a dural venous sinus or the jugular bulb are associated with injury to the underlying vein in two-thirds of cases.

4. Types of skull fractures 1) LINEAR FRACTURE This is the most common type of skull fracture and single fracture line goes through entire skull thickness; no displacement. They usually don’t cause any problems but sometimes they can cause damage to blood vessels underneath and result in a blood clot on the surface of the brain.
If the fracture extends to the base of the skull or sinuses it can result in problems on base of skull fractures. Etiology: Low-energy blunt trauma over wide surface area of skull. Clinically – just tender bump on head; skin may or may not be breached, most patients are asymptomatic, without loss of consciousness.

5. X-ray of linear skull Fracture

6. 2) COMPOUND FRACTURE Multiple linear fractures that radiate from impact site (≥ 2 bone fragments) This break in the skull involves a tear in the skin and splintering of the bone . Suggests more severe blow (than in single linear fracture). Portion of bone may be depressed.

7. 3) DEPRESSED FRACTURE This fracture involves fragments of bone being pushed downwards and can press below plane of skull. Etiology: Usually small blunt objects (such as hammer or baseball bat). This can cause damage to the underlying brain tissue. These types of fractures can sometimes result in focal seizures (from contusion underlying fracture). Clinically: depression under generalized swelling, focal seizures.

8. 4) BASE OF SKULL FRACTURE ( BASILAR FRACTURE ) This fracture occurs at the bottom of the skull and can involve the bones around the sinuses and ears. Etiology – impact to Occiput or sides of head . Basilar bones are thick – much more force required to fracture them. Often associated with dural tears. Clinically: Ecchymoses (periorbital / retroauricular) distant from point of impact, Cranial nerve palsies, CSF leaks, Pneumocephalus.

9. EPIDURAL HEMATOMA (EDH) EDHs occur between the inner table of the skull and the superficial layer of the dura and are often lenticular in shape. EDHs typically do not cross suture lines as the superficial dural layer is attached to the calvarium tightly along the sutures. In the rare case in which the fracture involves the suture (more common in children), one may visualize the EDH crossing the suture line.

10. In the pterional region, arterial EDHs classically arise from the middle meningeal artery. Venous EDHs can occur when the fracture crosses a dural venous sinus and can cross the falx cerebri and tentorium cerebelli. EDHs can be treated with surgical evacuation or middle meningeal artery embolization for stabilization of nonsurgical small- to medium-sized EDHs.

11. SUBDURAL HEMATOMA (SDH) SDHs occur between the dura and arachnoid mater. It is most commonly caused by a tear in a bridging cortical vein as it crosses the dura. It can also cross suture lines but not the falx or tentorium, as these are dural reflections.

12. The general progression of SDHs from acute to chronic is the appearance progressing from hyper- to hypoattenuating.. SDHs that are isoattenuating relative to the brain parenchyma can be acute. Eg :- Anemic patient or in a patient with an arachnoid tear. In subacute-to-chronic SDHs, the membranes are friable and can result in recurrent hemorrhage, resulting in an acute-on-chronic SDH. SDHs can be treated with burr hole drainage, craniotomy for evacuation, subdural evacuation port system placement, and/or middle meningeal artery embolization.

13. TRAUMATIC SAH Traumatic SAH occurs between the arachnoid and pia mater and is a usually small-volume sulcal SAH that commonly occurs at the site of impact (coup) or opposite the site of impact (contrecoup). Midline traumatic SAH (in the interhemispheric fissure or perimesencephalic cisterns) on initial head CT images is a marker of diffuse axonal injury (DAI) at subsequent MRI, with a 61% sensitivity and 82% specificity for severe DAI in one study. Isolated SAH in the basilar cisterns should prompt consideration of aneurysmal SAH, even in the setting of trauma. Traumatic SAH in the interpeduncular or perimesencephalic cisterns should raise suspicion for brainstem injury.

14. BRAIN CONTUSION Brain contusions are bruises of the brain parenchyma owing to impact. They characteristically occur at coup and contrecoup sites, most commonly in the inferior frontal lobes and anterior-inferior temporal lobes. MRI is more sensitive than CT for the detection of contusions, especially small or nonhemorrhagic contusions. Contusions can increase in size ( ie , “blossom” or “bloom”) over the first 48 hours after injury.

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