Common postoperative complications include mass lesions, infections, hydrocephalus, and infarctions Most occur in the immediate postoperative period, however, the clinician must have a heightened clinical suspicion for weeks after surgery Mass Lesions Hematoma A postoperative hematoma may be extra-axial, occurring in the epidural or subdural space or intra-axial, occurring within the parenchyma of the brain The clinical presentation of these lesions is not specific, and both should be included in the differential diagnosis for postoperative patients who become increasingly lethargic and exhibit focal signs such as hemiparesis, aphasia, cranial nerve palsy, or seizure Changes in vital signs, such as Cushing triad (hypertension, bradycardia, and abnormal respiratory pattern), may reflect increasing ICP (see Chapter 59 Pain: Headache ) A CT scan should be obtained if a developing hematoma is suspected and the patient’s condition is stable enough to permit a rapid work-up Patients whose neurologic condition is deteriorating with decreasing levels of consciousness require an endotracheal tube, not only for airway protection, but to allow hyperventilation The goal is a partial pressure of carbon dioxide (PCO2 ) level between 30 and 35 torr Hyperosmolar therapy may be necessary for the acutely decompensating patient Evidence exists for use of hypertonic saline or mannitol to rapidly decrease ICP Hypertonic saline may be given acutely in bolus doses of to 10 mL/kg of body weight Continuous infusions of 3% saline range between 0.1 mL and 1.0 mL/kg of body weight per hour Alternatively, Mannitol is given as an initial intravenous bolus of to 1.5 g/kg body weight Hematomas are usually treated by reexploration and evacuation of the mass lesion The patient whose condition deteriorates many days or weeks after craniotomy may have a chronic subdural hematoma Treatment is to drain by placement of burr holes with gentle aspiration, provided that the collection is not associated with enclosing membranes A chronic subdural hematoma with membranes can be evacuated only by full craniotomy Brain Edema Edema often accompanies neoplastic lesions and is more commonly associated with metastatic tumors On CT scan, brain edema appears as an area of decreased density associated with brain shift Brain edema is commonly associated with ICH and contusion Edema associated with cerebral infarction generally indicates a severe stroke and may lead to herniation The treatment of brain edema depends on the cause of the lesion Edema (vasogenic edema) caused by neoplasia or inflammation respond to treatment with steroids The role of steroids in treating edema caused by trauma, infarction, or anoxia is unproven Brain edema (cytotoxic edema) that occurs after surgery for trauma, infarction, or hemorrhage represents increased tissue water and may require hyperosmolar therapy as described above Pneumocephalus Pneumocephalus is simply the accumulation of air in the intracranial spaces It commonly occurs after craniotomy if the air is not completely evacuated before the bone flap is replaced It may also occur after a traumatic basilar skull fracture when air is introduced into the subarachnoid space by communication with the exterior environment, usually through the ethmoid, sphenoid, or frontal sinuses A CT scan may show the accumulation of air beneath a bone flap or in communication with one of the sinuses Most cases of pneumocephalus are treated with 100% oxygen by a nonrebreather mask Tension pneumocephalus marked by an enlarging pocket of air causing mass effect (midline shift, sulcal effacement, or both) demands more aggressive and invasive intervention Emergency surgery is necessary to resolve the mass effect Pneumocephalus can be an indication of CSF leakage Although pneumocephalus indicates a tear in the dura, a CSF leak indicates a relatively large dural tear allowing a stream of CSF to flow CSF may drain through the ethmoid or sphenoid sinus complex, causing rhinorrhea; through the mastoid air cells, causing otorrhea; or from the scalp suture line When rhinorrhea or otorrhea occur postoperatively, they should be treated conservatively with a lumbar drain If a seal is not accomplished after 10 to 14 days of conservative treatment, surgical intervention is necessary The use of antibiotics to treat either pneumocephalus or pneumocephalus with subsequent CSF leak is controversial Treatment with antibiotics should not be initiated unless signs and symptoms of CSF infection develop Hydrocephalus Types of hydrocephalus in the postoperative period include a loculated ventricle, communicating or noncommunicating A loculated (“trapped”) ventricle may cause symptoms resembling those caused by focal, expanding mass lesions A loculated ventricle occurs when the drainage pathway from one lateral ventricle into the third ventricle is blocked This blockage typically results from unilateral IVH or from a midline shift Diagnosis is confirmed with CT and must be followed by permanent drainage of the loculus The treatment of choice is emergent ventriculostomy and placement of a shunt The most common cause of communicating hydrocephalus is the blockage of absorption pathways by subarachnoid blood A CT scan shows universal dilation of all ventricles Lumbar puncture may demonstrate an elevated opening pressure Serial lumbar punctures may be performed as a temporizing measure to diagnose and treat communicating hydrocephalus If the patient’s neurologic condition improves after lumbar puncture, definitive treatment by shunting may be required Any lesion that causes an obstruction at the narrow fourth ventricular inflow or outflow track can create noncommunicating or obstructive hydrocephalus Obstructive hydrocephalus is commonly associated with lesions of the posterior fossa and is a dreaded complication of surgical procedures to this area of the brain Such lesions include cerebellar edema, infarct, or an intraventricular blood clot in the fourth ventricle Patients with a noncommunicating hydrocephalus can never be safely treated with lumbar puncture, because the pressure gradient created by this procedure places the patient at risk of tonsillar herniation and sudden death The patient may be temporarily stabilized with a ventriculostomy to provide decompression by draining CSF out of the intracranial cavity Permanent shunt placement is the definitive treatment for obstructive or noncommunicating hydrocephalus Infection Meningitis Meningitis may occur as late as weeks after surgery because of violation of mastoid air cells in the face of a CSF leak Unfortunately, after craniotomy the patient may normally exhibit all of the clinical signs of meningitis, including fever; therefore, the diagnosis may depend entirely upon examination of CSF and careful observation If a shunt reservoir is present, then CSF may be obtained with a shunt tap As mentioned in a prior section of the chapter, a CT scan or MRI of the brain should be performed prior to lumbar puncture Lumbar puncture in the backdrop of unrecognized hydrocephalus or mass lesion may risk a potentially fatal herniation syndrome The manifestations of postoperative meningitis are often much more subtle than those of the typical pneumococcal or meningococcal variety If signs of meningeal irritation should occur in isolation or in association with any other changes, neurologic or metabolic, examination of the CSF is mandatory before any antibiotics are administered Because cell count, glucose concentration, and protein concentration are abnormal after craniotomy, an absolute diagnosis must await the result of CSF culture or the demonstration of bacteria on Gram stain Empiric treatment with broad-spectrum intravenous antibiotics should be started immediately following LP and directed at gram-positive cocci and gram-negative organisms, as described in the previous section The antibiotic regimen should then be tailored once the final culture results and sensitivities have been obtained Ventriculitis The clinical picture of ventriculitis differs little from that of meningitis, although the presentation is usually much more subtle Meningeal symptoms may be minimal and fever variable, whereas alteration in mental status and neurologic function predominate Both meningitis and ventriculitis tend to occur in the postoperative period more than days after violation and contamination of the subarachnoid or ventricular space The only diagnostic test is microscopic and bacteriologic examination of the ventricular fluid As with meningitis, broad-spectrum antibiotics should be initiated pending Gram stain and culture results Abscess Brain abscess, or its immediate precursor, cerebritis, is relatively rare in the postoperative period If an abscess does not communicate with the ventricular or subarachnoid space, meningeal signs will usually be absent The development of meningeal signs or infected CSF in the face of focal deficits must heighten the clinician’s suspicion for abscess However, in 95% of cases of cerebral abscess, the CSF may be completely normal and ... effect (midline shift, sulcal effacement, or both) demands more aggressive and invasive intervention Emergency surgery is necessary to resolve the mass effect Pneumocephalus can be an indication of