Applications of fast-setting hydroxyapatite cement: cranioplasty.

A variety of autogenous and synthetic materials have been used to repair cranial defects resulting from traumatic and iatrogenic causes. In theory, the ideal material should be readily available and safe. It should adequately protect the underlying central nervous system, resist cerebrospinal fluid fistula formation, and be easily contoured. One promising synthetic biomaterial that has been used for cranioplasty is hydroxyapatite cement. This biomaterial has successfully restored cranial contour in most patients in whom it has been used; however, difficulties have arisen because of the material's prolonged water solubility. When exposed to cerebrospinal fluid or blood, inadequate setting of the cement occurs, resulting in loss of its structural integrity. This problem can be alleviated with the use of fast-setting hydroxyapatite cement, which hardens 6 to 12 times faster than the traditional cement. We present, to the best of our knowledge, the first series of the use of this material in 21 patients requiring cranioplasty. The advantages and limitations of fast-setting hydroxyapatite cement will be discussed.