nonsynostotic

Nonsynostotic is a medical term describing conditions of the skull or joints that occur without premature fusion of cranial sutures. In pediatrics, it is used to distinguish skull deformities not caused by craniosynostosis from those that are. This distinction guides evaluation and management.

The most common nonsynostotic skull deformities are deformational or positional plagiocephaly and other skull molding deformities resulting from external pressures during infancy, such as prolonged supine positioning or limited intrauterine space. Sutures remain open on imaging.

Etiology is usually mechanical or developmental, with no underlying bone disorder. Unlike nonsynostotic conditions, true craniosynostosis involves premature suture closure (sagittal, coronal, metopic, etc.).

Evaluation includes clinical exam, developmental assessment, and imaging when indicated to exclude craniosynostosis; ultrasound, radiographs, or CT with 3D models may be used.

Management is typically nonoperative: parental counseling, repositioning, tummy time, and, in selected infants, cranial remodeling helmets. Surgery is not a standard treatment for nonsynostotic deformities.

Prognosis is generally favorable, with many children improving with growth and nonoperative care; persistent or severe cases require ongoing specialist follow-up.