Cranioplasty using custom-made hydroxyapatite versus titanium: a randomized clinical trial

OBJECTIVE Cranioplasty is routinely performed in neurosurgery. One of its underestimated problems is the high postoperative complication rate of up to 40%. Due to the lack of good prospective studies and the small number of patients (5-20 each year) who receive alloplastic materials, decisions in favor or against a certain material are based on subjective empirical or economic reasons. The main goal of this study the first prospective, randomized multicenter study in Germany of custom-made titanium and hydroxyapatite (HA) implants was to compare local and systemic infections related to the implant within the first 6 months after implantation. Secondary objectives included comparing the reoperation rate, the complication rate, clinical and neurological outcomes, and health-related quality of life. METHODS The study included patient screening and randomization at 6 to 8 weeks before operation; pre-, intra-, and postoperative documentation until discharge; and postoperative follow-ups after 1 and 6 months. Approval for the study was obtained from the local ethics committee. RESULTS A total of 52 patients were included in the study. The rate of local implant associated wound infection in the HA group was 2 of 26 (7.7%) patients and 5 of 24 (20.8%) patients in the titanium group (p = 0.407). Systemic inflammation within 6 months after operation affected none of the patients in the HA group and 4 of 24 (37.5%) patients in the titanium group (p = 0.107). In both groups, 7 patients required reoperation after the 6-month follow-up (26.9% of the HA group and 29.2% of the titanium group; not significant). Reoperation with an explantation was necessary in 3 patients in each group (11.5% of the HA group and 12.5% of the titanium group; not significant). The results demonstrated a significantly higher number of epidural hematomas in the HA group in comparison with none in the titanium group. Altogether, 46 adverse events were found in 27 patients (54%). An improvement in the neurological outcome after 6 months was. experienced by 43% of the patients in the HA group and 26.3% of the, patients in the titanium group (p = 0.709). CONCLUSIONS The study emphasizes that cranioplasty is a high-risk intervention. In comparison with titanium, HA shows benefits in terms of the infection rate and the neurological outcome, but at the same time has a higher postoperative risk for epidural hematoma. Depending on the individual conditions, both materials have their place in future cranioplasty therapies.