Custom Porous Polyethylene Implants for Large-scale Pediatric Skull Reconstruction

Abstract

Some of the most problematic craniofacial injuries in pediatric plastic surgery are large calvarial defects in children who have passed the age of maximal dural osteogenic potential and yet are too young to yield split calvarial grafts. Porous polyethylene (Medpor; Porex) is an alloplastic material that can be customized to precisely match a cranial defect. We present a clinical series that demonstrates successful use of porous polyethylene cranioplasties in large pediatric cranial defects. From 2007 to 2009, 9 pediatric patients underwent custom-made porous polyethylene cranioplasties for large calvarial defects. Descriptive statistical analyses were performed on the cause of the defects, time to cranioplasty, size of defect, reconstruction technique, and postoperative healing. A total of 5 boys and 4 girls, with a mean age of 6.8 years, underwent 9 cranioplasties incorporating custom porous polyethylene implants. Initial pathologic findings included 7 patients with traumatic brain injuries, 1 patient with intractable seizures, and 1 patient with brain cancer. Initially, each patient had a craniectomy followed by replacement of the frozen bone "flap." All patients experienced either infection or resorption of the bone leading to a permanent defect. The mean defect size was 152 cm. The mean delay between the removal of failed bone "flap" and the final implant cranioplasty was 6.8 months. At the last follow-up, which averaged 3.6 months, all patients had stable wounds with acceptable cranial contour. For pediatric large-scale calvarial defects, custom-made porous polyethylene implants can be safely used for cranioplasty. Tissue expansion and acellular dermal matrix were useful tools to help augment the soft tissues of the scalp before cranioplasty to prevent complications of implant extrusion and wound breakdown.