[Materials for osteo-dural reconstruction in the cranium. An update].
Materials available for repair of a bony or dural defect at the cranial level are reviewed with particular attention stressed on their qualities and drawbacks for neurosurgical purposes. These materials include autologous or heterologous bone graft and biologically stable or biodegradable implants. No material can demonstrate ideal qualities of biocompatibility and biofunctionality. It should be either perfectly stable biologically and inert or perfectly biodegradable allowing simultaneous new bone reconstruction; moreover, it should be sterilizable, disposable, easy to handle and of low cost. Autologous grafts (iliac bone, split bone flap, pericranium...) have the best features but irradiated heterologous bone can be used instead; the latter needs a particular organization (bone graft bank) to fill the strict conditions of safety, especially regarding the risks of virus transmission. Implants have more recently been developed (acrylic, coral, B.O.P., ceramic, collagen-vicryl...) and present some drawbacks: generally high cost and not well established or insufficient biological properties. The experience of French neurosurgeons is reported from a questionnaire (102 answers) on the most frequently used materials. Autologous bone grafts, and acrylic as bone substitutes and pericranium for dural repair are preferentially used. Some materials, including coral, B.O.P. and collagen-vicryl, have a decreasing utilisation because of poor results especially with regards to bone incorporation and water tightness. Particular techniques (acrylic + teflon, acrylic with pre-op external casting and even non-repair of bone defects) are proposed by some neurosurgeons. New materials still under experimentation are finally presented (lyophilized bovine pericardium, collagen IV, polylactic acid).