FAILURE OF HYDROXYAPATITE CEMENT TO SET IN REPAIR OF A CRANIAL DEFECT- CASE-REPORT

OBJECTIVE AND IMPORTANCE: Hydroxyapatite cement, a new biomaterial tha t is being marketed as a method for reconstructing cranial defects, of fers many advantages. We document, herein, the complete dissolution an d failure of this material to set in a surgically dry field, under opt imal conditions, an occurrence that has not been previously reported. CLINICAL PRESENTATION: Hydroxyapatite cement was used for reconstructi on of a frontal bone defect secondary to a traumatic depressed cranial fracture in a 9-year-old male patient. At the time of suture removal on postoperative Day 6, we observed serous discharge from the wound, a reappearance of the cranial defect, and brain pulsations visible subc utaneously. INTERVENTION: The patient was returned to the operating ro om, at which time we learned that the hydroxyapatite cement had migrat ed out of the defect; small concretions of the cement were scattered t hroughout the subgaleal space. The concretions of cement in the subgal eal space and the small amount of cement remaining in the defect were removed, and titanium mesh was used. An excellent cosmetic result was achieved. CONCLUSION: Although offering many advantages, hydroxyapatit e cement does carry a risk of failure to set, despite optimal techniqu e. Causes for failure to set, as well as possible modifications in the use of material and technique, are discussed.