Surgery for Brain Edema

Peter Hutchinson, F.R.C.S.(SN); Ivan Timofeev, M.R.C.S.; Peter Kirkpatrick, F.R.C.S.(SN)

Disclosures

Neurosurg Focus. 2007;22(5):E14 

In This Article

Surgical Technique

There are many variations in the technique of decompressive craniectomy. Factors that should be carefully considered include the involved hemispheres (unilateral or bilateral), disease location (frontal, temporal, parietal, or occipital), size, and dural opening (dura left intact, dura left open, or dural graft patch).

In deciding which hemisphere is involved, one of the fundamental determinants is the presence of midline shift. In patients with TBI, diffuse brain edema, and no midline shift, bilateral craniectomy is advocated. This procedure can be performed in several ways. We advocate a bifrontal craniectomy from the floor of the anterior cranial fossa (avoiding the frontal air sinus) to the coronal suture posteriorly and to the pterion laterally. Although a bridge of bone in the midline can be left over the superior sagittal sinus, in our experience removing the bone completely (Fig. 2) enables one to perform a wide U-shaped dural opening based on the superior sagittal sinus. Ligation and division of the sinus and the falx at its most anterior extent relieve constriction. In patients with TBI, unilateral hemisphere swelling, and midline shift, a large, question markunilateral craniectomy is suitable. This technique is also appropriate in patients with hemisphere swelling due to ischemic stroke and SAH. The size of the craniectomy is of critical importance. Small craniectomies risk brain herniation with venous infarction and increased edema at the bone margins. Ashcoff et al.[4] have modelled the potential gain in volume depending on the size of the craniectomy.[4] Aiming for a minimum diameter of 10 cm enables a potential gain in cranial volume of 50 ml. In the past, craniectomies were performed without dural opening, but it is now recognized that the dura must be opened to achieve decompression. Whether the scalp is closed over the widely opened dura mater and lined with a sheet of Surgicel or whether a dural graft large enough to accommodate the expanding brain is performed is debatable. In our experience, however, we have found that leaving the dura open, resting on top of the brain and lined with a sheet of Surgicel, shortens the procedure, is not associated with the potential complication of CSF leakage, and provides a satisfactory plane for the subsequent cranioplasty. Csokay and colleagues[15] have described the creation of a vascular tunnel to prevent venous engorgement by avoiding compression of the cortical veins at the edge of the flap. In our experience, however, if the craniectomy is large, the tunnel is not necessary.

Figure 2.

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