Soft-helmet skull remodeling in canine models: intracranial volume unchanged by compensatory skull growth.

Abstract

OBJECT: Habitual sleeping positions in infants can produce occipital plagiocephaly, which causes strabismus as well as skull and facial asymmetry. This condition can be managed using a hard helmet, but maintaining an infant in such a device is often intolerable. The authors studied whether the shape of a young canine skull could reform while inside a soft helmet and whether intracranial volume would be preserved by the compensatory growth of the skull.

METHODS: The authors tracked the head sizes of 14 1-week-old beagles who wore long, soft helmets (study group) and seven beagles who did not (control group). From these measurements, the intracranial volume in each beagle was calculated. All crania were also studied radiologically by using plain skull radiography, computerized tomography (CT), and magnetic resonance (MR) imaging. The crania of all 14 beagles who wore soft helmets quickly adapted, resulting in a narrow, long head only 2 weeks into the experiment. This configuration continued to develop throughout the 7-week experimental period. At 8 weeks of age, animals in the study group showed no significantly different alteration in calculated intracranial volumes (p > 0.05). It is interesting that the helmet-treated animals initially underwent a paradoxical increase in intracranial volume growth. No structural difference in their brains was evident from CT or MR imaging findings, nor was there any functional disability.

CONCLUSIONS: Intracranial volume can be preserved by the compensatory growth of the skull during successful remodeling of the developing skull achieved using a soft helmet.