Intracerebral foreign body granuloma caused by a resorbable plate with passive intraosseous translocation after cranioplasty.

Numerous reports have demonstrated the usefulness of bioresorbable materials, but few have described severe complications caused by delayed degradation. The authors present the case of an intracranial foreign body granuloma caused by plates made of unsintered hydroxyapatite (uHA) particles and poly-l-lactide (PLLA; Super Fixsorb MX, Takiron) after cranioplasty. This 1-month-old boy presented to the authors' department with Pfeiffer syndrome. He had multiple-suture synostosis causing turribrachycephaly, Chiari malformation Type 1, and obstructive sleep apnea syndrome. At 6 months old, the child was treated with multidirectional cranial distraction osteogenesis. The uHA-PLLA plates were applied as base stones to reinforce the pins. After 16 days of distraction and 3 weeks of consolidation, the pins were removed. Seventeen months postoperatively, the plate on the right temporal bone showed passive intraosseous translocation (PIT), and by 2 years postoperatively, the plate was completely left behind in the cerebrum. At 3.5 years postoperatively, MRI disclosed a contrast-enhanced mass with surrounding brain edema at the site of the plate. The lesion was resected. The clinical history and histological specimens led to a diagnosis of foreign body granuloma surrounding the nonabsorbed resorbable plate in the dura mater. Resorbable plates are clearly useful resources in cases in which delayed absorption will not prove problematic, but careful application and follow-up is required when dealing with the growing skull given the possibility of intracranial displacement after PIT.