Cranial vault distraction: its illusionary effect and limitation

Distraction osteogenesis has some advantages, such as less hazardous complications, less scarring, and fewer bone defects. However, it has not been fully accepted yet because of a unidirectional expansion along the distraction device. Because cranial expansion is limited by scalp tension and soft-tissue scarring, undercorrection of the cranium and relapse of the vault deformities have occasionally been seen on long-term follow-up. These patients also had so much bone defect that the donor bone was inadequate for immediate revisions, and dissection under the scalp was complicated.

The authors used distraction osteogenesis to treat 12 cases of craniosynostosis. Five patients were syndromic (two cases of Pfeiffer's syndrome, two cases of Crouzon's disease, and one case of Apert's syndrome), and seven were nonsyndromic (four cases of brachycephaly, two cases of scaphocephaly, and one case of plagiocephaly).

After only unidirectional expansion without vertical reduction, the shape of the cranium was satisfactorily improved, which might have been an illusion caused by the relative reduction attributed to the elongation by the distraction osteogenesis and, in brachycephaly, alteration of the patient's head position resulting from inclination of the facial plane by forehead advancement. However, in scaphocephaly, the unique deformity in the occipital and frontal regions remained after simple distraction. Distraction osteogenesis should be applied for a narrow cranium because the bone defect and scalp closure could pose problems. Radical reshaping should be used in cases of sufficient donor bone and scalp closure. Although additional surgery is unavoidable for device removal, minor revisions can be performed for revision of the irregularity at that time.

Except for prolonged treatment, based on minimally invasive operations, distraction cranioplasty might be applied extensively in cases of craniosynostosis.