Squamous Suture Synostosis: A Review With Emphasis on Cranial Morphology and Involvement of Other Cranial Sutures.

Squamosal suture synostosis has received little attention, potentially due to its rare nature. The authors present here a clinical report of isolated unilateral squamosal suture synostosis and a literature review, which produced 6 articles describing 33 patients of squamosal synostosis. Of the reported patients, 15 were associated with a craniofacial syndrome, 10 were nonsyndromic, and 8 were not specified. The cranial morphology varied greatly and only 1 patient was consistent with the morphology predicted by Virchow law-decreased vertical growth with compensatory ipsilateral longitudinal growth (manifesting as occipital and possibly frontal zygomatic bulging). Additional suture synostoses were observed in 36.3% of nonsyndromic and 80% of syndromic patients, suggesting that either squamosal synostosis may have an effect on other sutures, or more likely, only the most severe patients are recognized and reported. Surgical and nonsurgical interventions have found limited utility due to the subtle nature of the cranial defects and a lack of increased intracranial pressure, with a conservative follow-up course being the preferred treatment.