Treatment of epidural hematoma The surgical procedure consists of placement of burr holes in a truly emergency situation in the ED or at the bedside or, preferably a craniotomy, drainage of the hematoma, and identification and ligation of the bleeding vessel. The operative results are excellent except in cases with extended fractures and laceration of the dural venous sinuses, in which the epidural hematoma may be bilateral rather than unilateral. If coma, bilateral Babinski signs, spasticity, or decerebrate rigidity supervene before operation, it usually means that displacement of central structures and compression of the midbrain have already occurred; prognosis is then poor, but a few patients do well if surgery is not greatly delayed. Small epidural hemorrhages can be followed by serial CT scanning and will be seen to enlarge gradually for a week or two and then be absorbed. There is controversy about the benefit of removing these smaller clots in a patient who has no symptoms or signs; with sequential clinical and imaging surveillance, can be left alone.
The problems created by acute and chronic subdural hematomas are so different that they must be considered separately. In acute subdural hematoma, which may be unilateral or bilateral, there may be a brief lucid interval between the blow to the head and the advent of coma. More often, the patient is comatose from the time of the injury and the coma deepens progressively. Acute subdural hematoma may be combined with epidural hemorrhage, cerebral contusion, or laceration. The clinical effects of these several lesions are difficult to distinguish and there are a few patients in whom it is impossible to state before operation whether the clot is epidural or subdural in location. Subdural clots more than a few millimeter in thickness can be accurately visualized by the CT scan in more than 90 percent of cases, but the window settings must be appropriate to avoid obscuring of the clot by adjacent bone (Fig. 34-9). A large acute clot causes a shift of midline structure as well as marked compression of one lateral ventricle; but if there are bilateral clots, there may be no shift and the ventricles may appear symmetrically compressed.
Rapidly evolving subdural hematomas are usually a result of tearing of bridging veins, and symptoms are caused by compression of the adjacent brain and of deep structures. Unlike epidural arterial hemorrhage, which is steadily progressive, the rising ICP usually arrests the venous bleeding.
Exceptionally, the subdural hematoma forms in the posterior fossa and gives rise to headache, vomiting, pupillary inequality, dysphagia, cranial-nerve palsies, and, rarely, stiff neck, and ataxia of the trunk and gait if the patient is well enough to be tested for these functions. Because of their apposition to bone or an axial orientation along the tentorial dura, posterior fossa clots are likely to be overlooked in CT scans.