Cranial Defect Regeneration in a Reserved Space

Abstract

Cranial defects exceeding a certain size do not heal spontaneously and require surgical treatment. The prevention of uncontrolled soft-tissue ingrowth is crucial in the bony healing of such defects. Bone regeneration of full-thickness cranial defects was assessed in 16 adult New Zealand White rabbits. A single epicranially placed cover was compared with a hollow chamber with an additional barrier on the dural side. After 8 weeks, bone regeneration in the defects was assessed radiologically, histologically, and by fluorescence microscopy. The hollow chamber design resulted in almost complete cranial defect healing. In contrast, five out of 16 defects covered with a single epicranial burr-hole cover showed hardly any visible bone. Inside the reserved space, there was twice as much bone coverage as compared with burr-hole covers only. Providing a reserved space for bone regeneration reduces the statistical spread significantly and thus makes the clinical outcome more predictable. Use of a hollow chamber can serve as a useful tool to assess the effect of bone-stimulating factors such as growth factors and bone substitutes. Hollow resorbable implants may offer a new approach in bone regeneration by reducing the need for bone autografting and the associated donor-site morbidity.