Hemicraniectomy is a Promising Treatment in Ischemic Stroke

The most devastating form of ischemic stroke is the large cerebral infarction.This type of infarction is commonly associated with cerebral edema which produces mass effect.If this mass effect is extensive enough, brain herniation and death can result.Hacke et al 1 have coined the term 'malignant'middle cerebral artery (MCA) territory infarction to describe the complete MCA territory infarction resulting in significant space occupying effect.In a large neuroprotective trial, LUB-INT-9, 2 25% of all stroke mortality was patients with 'malignant'MCA syndrome who developed brain herniation.Clinically, 'malignant' MCA infarction results in the early depression of consciousness that deteriorates to coma and brain death within two to five days in almost 80% of patients when treated with medical therapy alone.1,3 The incidence of this form of infarction is estimated at 3%-5% of all ischemic stroke.Neurologic deterioration from large cerebral infarction is known to correlate with horizontal displacement of the anterior septum and the pineal gland rather than with intracranial pressure (ICP) elevation.Recent evidence suggests that ICP elevation is a terminal and, most likely, an irreversible circumstance that results when mass expansion exceeds intracranial compliance.Medical therapy aimed at reducing ICP primarily contracts healthy brain tissue volume and may aggravate pressure differentials, causing devastating shifts in brain tissue.4 Ideal therapy should prevent the formation of brain edema and the subsequent displacement of tissue.Current medical therapies l a rgely fail to prevent either.Decompression surgery is a controversial approach to decreasing the devastating consequences of mass effect and tissue shifts caused by intracranial mass lesions.Hemicraniectomy and durotomy describe a neurosurgical decompressive approach to hemispheric masses and swelling.This was first performed as a treatment for acute subdural hematoma.5 Hemicraniectomy involves removal of bone on one side of the skull and simultaneous generous dural opening.The minimal adequate decompression is defined by the following bony boundaries (Figure 1): 1) anterior, frontal to midpupillary line 2) posterior, approximately 4 cm to the external auditory canal 3) superior, to the superior sagittal sinus 4) inferior, to the floor of the middle cranial fossa Bone removed during a hemicraniectomy can be saved in a bone bank in antibiotic solution at -80 o C. The bone flap can also be stored in the peritoneum by surgical implantation.Bone is replaced after the swelling has subsided in one to three months.Cruciate or circumferential durotomy must be performed over the entire region of bony decompression to insure that nothing