Page 76 - Clinical relevance of current materials for cranial implants

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Chapter 3
DISCUSSION
This study shows that cranioplasties with an autologous bone flap fail frequently. One in every five autologous bone flaps eventually had to be removed because of infection, bone flap resorption, subcutaneous fluid collections, or hematoma. Several factors were found to be related to bone flap failure.
Complication rates in cranial reconstructions are high, often resulting in removal of the reconstruction2,4,6,11–13,16,18,19,22,27–31. Current literature reports a median removal rate of 10.4% (ranging from 0-50%) for autologous bone flaps and for combined alloplastic cranioplasties 5.1%31.
Age
Age has been postulated as an influencing factor for the emergence of infections after cranioplasty with autologous bone. Higher metabolic activity in young patients could lead to quicker resorption, but the exact mechanism responsible for this is unclear.12,13,30,34,35 Resorption rates of 1%-50%4,6,12,13,16,22,27,30,36 have been observed for autologous bone flaps, while younger patients may have even higher resorption rates12,22,26,30,36,37. The present study confirmed this association.
Indication for decompressive craniectomy
In this study, an association was found between a neoplasm as the initial diagnosis for decompressive craniectomy and higher infection rates. This patient population did not receive standard radiotherapy as a possible explanation for this association. The current literature also does not offer an explanation, but the slow onset of this disorder likely has a negative impact on recovery, as these patients generally have a suboptimal health condition.