Autologous bone flap cranioplasty
The bone that is removed at the time of craniectomy has been preserved for future implantation. This is generally not employed in contaminated cases (penetrating trauma, infection…).
Available evidence on the safety of cranioplasty materials is limited due to a large diversity in study conduct, patients included and outcomes reported. Autologous bone grafts appear to carry a higher failure risk than allografts. Future publications concerning cranioplasties will benefit by a standardized reporting of surgical procedures, outcomes and graft materials used 1).
a) in a“pocket” created in the patient’s subcutaneous abdominal fat
b) in preservative(e.g.RPMI and stored in ultra low temperature freezer
It is a simple and cheep alternative to other techniques and is available to any institution that provides autoclaving sterilisation services. 2).
Inherent difficulties of bone storage and cranioplasty are neglected in the literature.
The timing of cranioplasty and method of bone flap storage are known risk factors of non-union and resorption of bone flaps
Silay et al. present a simple method of bone storage and autologous cranioplasty in a small child with severe head injury. The child underwent surgical treatment with decompressive craniectomy. A bone flap was transversally divided into two pieces and stored under the galea. Bone storage and reconstruction of the cranial vault with this surgical technique is a safe, easy and cost-effective choice excluding the surgical trauma to obtain a new subcutanous pocket for bone storage in pediatric decompressive craniectomy patients 3).
Although generally accepted concept about timing of cranioplasty using autologous bone is that early cranioplasty has more risk of infection and delayed cranioplasty has risk of non-union or resorption of bone flap.
Shin et al. observed new bone formation on all the frozen autologous bone flaps that was stored within 8 weeks. The timing of cranioplasty may showed no difference of degree of new bone formation. Not only the healing period after cranioplasty but the time interval from craniectomy to cranioplasty could affect the new bone formation 4).