OBSERVATIONS ON A RECENT INCREASE IN PLAGIOCEPHALY WITHOUT SYNOSTOSIS

Objective. To verify and determine the cause of an increase in the ref erral of infants with plagiocephaly without synostosis (PWS) to a sing le tertiary craniofacial center. Design. A chart review was performed for 269 infants with a diagnosis of PWS who presented to a single tert iary craniofacial center between 1979 and 1994. The pattern of referra l for PWS was analyzed using both simple linear regression and time se ries regression analyses. In addition, the referral pattern for PWS wa s compared with that for infants seen at the same center who received a diagnosis of synostotic plagiocephaly. Changes in the distribution o f several demographic, perinatal, and clinical variables during the st udy period were also assessed. Finally, in an effort to identify corre lates of the risk of PWS developing, characteristics of patients who w ere Missouri residents and presented between 1992 and 1994 were evalua ted and compared with those of the 1993 Missouri live birth cohort. Se tting. The Cleft Palate and Craniofacial Deformities Institute, St Lou is Children's Hospital, Washington University Medical Center. Results. The average annual number of referrals to our center for PWS in the p eriod 1992 to 1994 was more than sixfold greater than that for the pre ceding 13 years. There was a statistically significant increase in the annual number of referrals to our center during the 16-year study per iod. Moreover, there was evidence that the average annual increase in referrals was significantly greater during the last 3 years (1992 thro ugh 1994) of the study than in the first 13 years. This shift in the r eferral patterns is roughly contemporaneous with the American Academy of Pediatrics recommendations regarding infant sleep position. There w as no evidence that either the mean number of referrals or the average annual increase in referrals for patients with synostosis changed dur ing the study period. Among patients with PWS, the average age at pres entation did not change during the study period. There were also no si gnificant changes in the distribution of other demographic, perinatal, and clinical variables. When compared with the Missouri birth cohort, infants with PWS were significantly more likely to be boys and to hav e been delivered by forceps. There was also some evidence that patient s with PWS were more likely to be born prematurely and to be products of multiple-gestation pregnancies. These associations were, however, o f only borderline statistical significance. Conclusion. Referrals to o ur center for PWS increased markedly in 1992 relative to previous year s. The temporal coincidence of this increase with the American Academy of Pediatrics recommendation to avoid the prone sleeping position, to reduce the risk of sudden infant death syndrome, suggests a possible causal relationship. If this association is causal, education regardin g the need for head position rotation coupled with that for sudden inf ant death syndrome should obviate positional PWS.