2015 HSC Section 1 Book of Articles

Management of nonsyndromic craniosynostosis Okada and Gosain

accompanying displacement of the ipsilateral superior orbital rim towards the synostotic suture, known as the ‘harlequin deformity’ (Fig. 3). There is compensatory contralateral forehead bossing and a subsequent inferior displacement of the contrala- teral superior orbital rim. Predictable facial deform- ities also accompany unilateral coronal synostosis: the nasion is deviated ipsilaterally, the ipsilateral zygoma is displaced anteriorly and the chin point is displaced to the contralateral side. Bilateral coronal synostosis is more often associated with craniosy- nostosis syndromes (Fig. 4). The resulting deformity is brachycephaly, or short head. There is shortening in the anterior–posterior dimension, bilateral reces- sion of the superior orbital rims and excessive height of the anterior forehead. Lambdoid synostosis is the rarest form of syn- ostosis, and can be mistaken for deformational pla- giocephaly. In true synostosis, there is ipsilateral occipital flattening, compensatory bulging of the contralateral occiput, and a deviation of the petrous temporal bone toward the offending suture, causing the external ear to be malpositioned posteriorly (Fig. 5). The head assumes a trapezoidal shape viewed from above. In deformational plagiocephaly, there is ipsilateral occipital flattening, but ipsilateral frontal bossing and contralateral frontal flattening, creating a parallelogram shaped head without defor- mation of the cranial base. In the last 15 years, we have expanded our knowledge of the genetics of craniosynostosis.

KEY POINTS The treatment of nonsyndromic craniosynostosis begins with the proper diagnosis. Computed tomography scans remain the gold standard imaging modality. Cranial vault remodeling achieves the desired cranial contour without relying on underlying brain expansion,

thus allowing treatment for older children. Minimally invasive alternatives such as strip

craniectomy with helmet therapy are limited to patients under 6 months of age, as they rely on rapid brain expansion to achieve the desired cranial shape.

premature suture closure causes predictable restric- tion and compensatory growth was developed by Virchow [6]. According to Virchow’s law, premature suture fusion results in decreased growth perpen- dicular to the suture and increased compensatory growth parallel to it. The predictable clinical phe- notypes of single suture synostoses are as follows. Metopic craniosynostosis results in trigonocephaly, a keel-shaped deformity with midline forehead ridg- ing, and narrowed bitemporal distance (Fig. 1). Sag- ittal craniosynostosis causes scaphocephaly, a long ‘boat-shaped’ head with narrowed interparietal dis- tance and compensatory lengthening in the anterior posterior dimension (Fig. 2). Unilateral coronal syn- ostosis results in anterior plagiocephaly character- ized by recession in the ipsilateral forehead; there is

FIGURE 1. 6-month-old male with metopic synostosis.

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