Composite autogeneic human cranioplasty: frozen skull supplemented with fresh iliac corticocancellous bone.

Skull totally exteriorized during craniotomy becomes nonviable. Resorption of the reimplanted cranial section occurs variably according to its treatment, the properties of the recipient bed, and the metabolic conditions of the host. Neurosurgeons commonly deep freeze autogeneic skull for preservation before delayed autogeneic cranioplasty. Aseptic necrosis commonly follows replacement of the autograft in its former cranial bed. This clinical study of six patients represents an attempt to block this destructive resorption by supplementing the frozen autograft with fresh corticocancellous autogeneic ilium. Observations of these patients ranging in age from 12 to 52 years support the following conclusions: (a) Osteogenesis was not enhanced by the addition of fresh corticocancellous bone to the frozen autoimplant. (b) The period of time that the autoimplant was frozen did not influence its subsequent biological behavior after cranioplasty. (c) Sterilization with ethylene oxide and in one case additional gamma irradiation did not impair the quality of the implant compared to those not sterilized. (d) Resorption occurred in both frozen and fresh but devitalized autogeneic skull. (e) Autogeneic skull is repaired by osteoconduction rather than by inducing competent perivascular stem cells to become osteogenic. (f) Freezing of autogeneic skull for preservation is practical, acceptable, but suboptimal from the perspectives of cerebral protection and cosmetic reconstruction. (g) The supplementation of the frozen autoimplant with fresh corticocancellous bone increases operating time and patient discomfort without affording additional benefit.