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American Association of Plastic Surgeons
25. The Use of Hydroxyapatite Bone Cement in the Repair of Large Full Thickness Cranial Defects: A Caution
Andrea Moreira-Gonzalez, MD, James E. Zins, MD.
Cleveland Clinic Foundation, Cleveland, OH, USA.

Purpose: Over the past 8 years our experience with hydroxypatite bone cement (HAC) for the reconstruction of cranial defects in over 120 patients has resulted in the establishment of strict criteria for its use. While our overall complication rate with HAC was low, certain patient groups have an unacceptably high complication rate. The object of this report is to describe our experience in the repair of large, full-thickness cranial defects using hydroxyapatite cement.
Method: Between 1997 and 2004, HAC was utilized in 121 patients. Of these 121 patients, 14 patients underwent correction of large, full-thickness skull defects. Large defects were arbitrarily described as greater than 25cm2. These 14 patients were retrospectively reviewed and data relevant to each case was collected and evaluated. The majority of the patients in this study were referred to us by Neurosurgeons to correct post-craniectomy defects. Surgical technique in all patients included the use of titanium mesh to reconstruct the floor of the defect with rigid fixation to the surrounding native bone, the interposition of hydroxyapatite cement to ideal contour, and closure of the defect once the cement was dry. Suction drains were used in all patients.
Results: Mean age was 35 years (range 1-69). The mean defect area was 70.9 cm2 (range 30-150 cm2). Cases were equally divided between BoneSource® and Norian‘. The mean amount of HAC used was 28.4 g. Follow-up varied between 1 and 6 years with a mean of 3 years. Major complications occurred in 6 out of 14 patients (42.8%), some of them occurring as late as 4 years postoperative (Table 1). All six patients underwent complete removal of the HAC. The main problems observed during the reoperation were fragmentation of the HAC, exudation and severe soft tissue inflammatory reaction. Of the complicated cases, four underwent further skull reconstruction either with autogenous bone or HAC without further problems.
Conclusions: Because the high complication rate with the use of hydroxyapatite cement in large skull defects, we have returned to the use of autogenous split skull cranial bone reconstruction for these patients, and recommend that the use of hydroxyapatite in large skull defects be approached with caution.
Table 1. Complicated patients profile.

PatientAgeGenderPrimary DiagnoseDefect area (cm sq.)Defect regionCommercial preparationAmountComplication
158FemaleAneurism63FrontotemporalBoneSource60HAC fragmentation + infection
240FemaleBrain tumor72TemporoparietalNorian15Infection
34MaleIntractable seizure108TemporoparietalBoneSource20HAC fragmentation + infection
436FemaleHemagioma63ParietalBoneSource50HAC encapsulation
520MaleBrain tumor42.2OccipitalNorian10HAC fragmentation
654MaleBrain tumor132ParietalBoneSource25HAC fragmentation + infection

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