الفهرس 
DEVELOPMENT OF THE CALVARIAOnly 14 pages are availabe for public view
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Abstract
C
alvarial bone defect are frequently the result of trauma, previous operative procedure, infection, or neoplasm. Making the decision regarding the need for repair is frequently not difficult. Its timing dependent on the patient’s neurological conditions, the risk of infection, and the healing potential of the surrounding tissue. The operative procedure for repair of these cranial defects is determined by the size of the defect, its location, and the implant material employed.
It is generally accepted that protection of the brain is one of the most important indications for cranioplasty, although brain injury due to a cranial defect is rare. Cosmetic problems also need cranioplasty. The syndrome of trephined (seizures and cerebral atrophy) are also considered indications for cranioplasty, although the clinical evidence remains controversial. Neurological deficits as hemiparesis, sensory disturbance, and aphasia improved dramatically after cranioplasty.
To be suitable for cranioplasty, the material must meet several criteria. It must be biologically inert, nonresorbable, nonantigenic, relatively inexpensive, readily available, radiolucent, sterilizable, pliable, and light-weight but strong enough to withstand impact. In addition, the material should have low thermal and electrical conductivity and a low propensity for infection. In children, the material should be able to allow the skull to growth. Although no currently available material satisfies all of these requirements.
Fresh and subcutaneously preserved autografts are the best at present. Autogeneous endochondral bone an membranous bone are excellent substitute materials. Membranous bone can be harvested from the surrounding calvaria. A graft of such bone can be harvested through the same incision as the one needed for exposure of the cranial defect. Membranous bone also offers the advantage of having a lesser potential for resorption than endochondral bone grafts. Endochondral bone cane be taken from a rib or iliac crest. Rib and iliac crest bone grafts are more difficult to shape into the desired configuration but are an excellent source of bone when large implants are needed.
Alloplastic cranioplasty is frequentaly employed for the repair of cranial defects. Although popular during World War П, metallic materials have fallen into disfavor because of their inherent properties of poor malleability, excellent thermoconductive capacity, and interference with current radiological techniques. Methylmethacrylate is an alloplastic material that is easy to mold and shape and more amenable to the repair of large defects. Acrylic is similar in strength to bone and does not interfere with computed tomography or magnetic resonance imaging. It is ideal for fronto-orbital cranioplasty because it can be feathered along its edges to make an unobtrusive junction with the surrounding bone that produces an aesthetically pleasing result. However, its use should be avoided when bacterial contamination is likely because of the increased risk of infection.
A new technique for cranioplasty with L-shaped titanium plates and compination ceramic implants composed of hydroxyl apetite and tricalcium phosphate and also advanced technique by endoscopic cranioplasty with calcium phosphate cement for pterional bone defect after frontotemporal craniotomy.
There are several common complications of cranioplasty, the most serious of which is late infection.