Occipital Plagiocephaly: Deformation or Lambdoid Synostosis?

Abstract

Between 1987 and 1992, 30 infants aged 1.4–13 months (mean 7.3 months) underwent unilateral lambdoid strip craniectomy at the Children’s Hospital of Buffalo for occipital plagiocephaly. Males outnumbered females (22:8) and right-sided occipital flattening was significantly more common than left-sided flattening (25:5). The deformity was noticed at an average age of 3.2 months; 16% of the infants had an asymmetry at birth. Positional preferences (a distinct tendency to lie preferentially on the back, in most cases with the head turned to the ipsilateral side) were described in 79% of infants for whom this information was available, and torticollis was present in 10%. Pre- and postoperative CT scans were analyzed using several morphometric measurements. Asymmetries were measured between the flattened and contralateral sides, both posteriorly and anteriorly, using a translucent grid placed over the CT slice showing maximum asymmetry. The average maximum asymmetry between the flattened and contralateral sides was 24% posteriorly and 16% anteriorly. Significant improvements were seen postoperatively, with both anterior and posterior asymmetries improving by an average of one third (p < 0.05). However, when compared with CT scans from a control group of infants without synostosis, the operated group showed persistent and significant asymmetries postoperatively. The morphometric measurements described allow an objective and reproducible means of assessing the results of various treatments for this disorder. The improvements following unilateral lambdoid craniectomy are difficult to interpret in isolation; we suggest that future efforts be directed toward similarly assessing the results of both nonoperative treatments such as positional changes and molding helmets, and more aggressive surgical treatments that have been advocated for this disorder.

Incidence of Cranial Asymmetry in Healthy Newborns

“…Both multiple birth and intrauterine constraint have been reported as risk factors for fully expressed deformational plagiocephaly. 30,36 We observed a prevalence of 56% of head flattening in twin births, which is presumably a reflection of intrauterine constraint. The effects of this constraint are discussed controversially.…”

“…Localized flat areas are more likely to occur with primiparity, assisted delivery, and long labor. All of these conditions have also been identified as risk factors for deformational plagiocephaly 36 and for other deformational anomalies. It is obvious that they cause increased molding, acting on the fetal head during delivery.…”

“…As this flattening is quite subtle, it is frequently overlooked in the neonatal period. This explains why most mothers of infants with deformational plagiocephaly recall that their infant had a normal head shape after birth, 36 and why parents and pediatricians often do not notice deformational plagiocephaly until 2 to 3 months of age. 5 This study showed a prevalence of 13% of localized cranial flattening in essentially healthy newborn singletons.…”

Determinants of Nonsynostotic Plagiocephaly: A Case-Control Study

“…Clearly, supine sleeping position is implicated, [12][13][14][15] but it is uncertain whether additional factors can affect the risk of developing plagiocephaly.…”

Long-Term Developmental Outcomes in Patients With Deformational Plagiocephaly

“…More commonly, deformational plagiocephaly occurs postnatally and is associated with congenital torticollis, vertebral anomalies, neurologic impairment, or forced sleeping position. [3][4][5] Few reports document any late effects of deformational plagiocephaly other than potential cosmetic concerns and the potential for strabismus, especially involving vertical eye movements. 6,7 Plagiocephaly may be morphometrically evident in as many as 14% of adults, but it is rarely recognized.…”