Introduction

Nonaccidental trauma (NAT) is one of the main causes of pediatric morbidity and mortality in the United States, and it is estimated that more than 1,000 children die every year from such causes.1 Of these deaths, ~80% are the product of head trauma, and 19 to 38% of pediatric head trauma cases have been shown to result from physical abuse or neglect.1 2 3 Additionally, pediatric trauma resulting from nonaccidental causes has been shown to have a significantly higher mortality than accidental trauma.2 3 4 The ability to identify potential child abuse victims would prevent significant morbidity and mortality in children.

While some studies have shown associations between child maltreatment and rural residence,4 5 age,6 sex,7 parental mental health,8 and family instability,6 ultimately, there are, as of this writing, no tools for identifying potential abuse victims before the onset of trauma. Currently, even the tools available for diagnosing victimized children are lacking in sensitivity,1 9 and most of the current literature focuses on identifying abuse following admission to the hospital. Given the concerns outlined earlier, we hypothesized that deformational plagiocephaly (DP), a malformation of a child’s skull that often results from too much time spent lying supine, could act as an early predictor of abuse or neglect. It is a condition that is relatively easy to screen for and the techniques for measurement could easily be applied to rural clinics and emergency room without imaging. However, the current literature is divided on the actual prevalence, incidence, and consequences of DP, which makes comparing our nonaccidental trauma and neglect population to the general population difficult. To help address this inconsistency in the literature, we characterized the occurrence of plagiocephaly and child maltreatment at two west Texas institutions with a large, rural catchment area. We then used these data to evaluate any possible correlation between DP and child maltreatment in our study population.

Methods

After obtaining Institutional Review Board approval, charts for children younger than the age of 4 years with a diagnosis of NAT (ICD-9: 995.59; ICD-10: T76.12XA), child neglect (ICD-9: 995.52; ICD-10: T76.02XA), and/or unspecified head injury (ICD-9: 959.01; ICD-10: S09.90XA) were collected. Children with developmental delay and torticollis were excluded as these conditions are independent risk factors for DP.10 Charts that lacked neuroimaging studies were excluded from analysis. Thus, out of 396 charts that met the inclusion criteria, a total of 76 were used in this study. Demographical information was attained from patients’ charts and the evaluation of socioeconomic status (SES) was accomplished using U.S. census data on the median household income for the subject’s listed zip code of residence.

Utilizing axial computed tomography (CT) scans, the cranial vault asymmetry index (CVAI) and cranial index (CI) were calculated as described by Loveday and de Chalain11 (Fig. 1). The current model for assessing severity of plagiocephaly was also used.12 In this model, a CVAI < 3.5% indicates normal head symmetry (Level 1), 3.5 to 6.25% indicates minimal asymmetry (Level 2), 6.25 to 8.75% indicates moderate to severe posterior quadrant flattening (Level 3), 8.75 to 11.0% indicates severe posterior quadrant flattening with moderate ear shift (Level 4), and > 11.0% indicates severe posterior quadrant flattening with severe ear shift (Level 5). Therefore, a CVAI > 3.5% constitutes a diagnosis of DP. Additionally, we assessed the presence of brachycephaly via CI, with a value above 0.9 mm being diagnostic for brachycephaly. The calculations for CVAI and CI were performed immediately above ear level on the appropriate CT cut, which allowed us to apply head measurements at the widest diameter of the skull.

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Fig. 1 Model of CT cut and method of calculating CVAI and CI. CI, Cranial Index; CVAI, cranial vault asymmetry index.

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Fig. 1 Model of CT cut and method of calculating CVAI and CI. CI, Cranial Index; CVAI, cranial vault asymmetry index.

Next, scales were created to assess the characteristics of initial clinical presentation as well as severity of the patient’s history (Tables 1 2). Neglect history was stratified into “supervisory” and “physical” neglect.13 Finally, demographical information was collected for each patient, including age, race, ethnicity, sex, and median household income.

For our analysis, severity of initial presentation, severity of history, and severity of brachycephaly were evaluated in children with and without DP. Also, children with DP in the NAT group were compared with those diagnosed with DP in the neglect group using the same factors. Statistical differences between the groups were assessed using Wilcoxon’s rank-sum test for continuous variables and Fisher’s exact test for categorical variables. A p-value of 0.05 or less was considered statistically significant. All analyses were conducted using SAS 9.4 (Cary, North Carolina, United States).

Results

The prevalence of plagiocephaly within the combined cohort of NAT and neglect patients was 21% (Table 3). The percentage of NAT patients with DP was 23.68% and the percentage of neglect patients with DP was 18.4% (Tables 4 5). There was no logistical correlation between CVAI and characteristics of initial presentation or history of trauma for either NAT (p = 0.359 and 0.250, respectively) or neglect patients (p = 0.116 and 0.770, respectively). No significant association was found between brachycephaly and plagiocephaly in either the NAT (p = 0.148) or neglect (p = 0.425) groups. The median age for children in the NAT and neglect group that were diagnosed with plagiocephaly was 3 months (Table 4) and 12 months (Table 5), respectively. Finally, no predictive significance was seen between age, ethnicity, race, or SES and a history of NAT or neglect (Tables 4 5). All associated p-values and information on additional studied variables for each group are shown inTables 3 4 5.

Discussion

Our findings demonstrate no correlation between DP and a history of neglect or trauma in our rural, pediatric population. Additionally, none of the demographic variables assessed showed a significant correlation with plagiocephaly, neglect, or trauma. The prevalence of DP for the entire cohort, as well as in the NAT and neglect groups independently, was within the range of DP prevalence nationally—20 to 50%.14 15 As of this writing, the concept of DP as an associated risk factor for abuse has not been explored in the literature, so there is little evidence available to help place our findings in context.

Numerous confounders could explain the lack of relationship between DP and NAT/neglect observed in this study. We chose to evaluate children younger than the age of 4 years for maximum coverage, since most of the resulting morbidity and mortality from NAT or neglect have been shown to occur before the age of 3 years.16 However, the wide age range could have confounded our findings. To combat this, we stratified the data based on children less than and more than 12 months of age, but significant correlation between NAT/neglect and DP was still not established. Since the median age for the NAT and neglect groups were 3 and 12 months, respectively, adaptation of the skull in the neglect group could have potentially skewed the prevalence rates in this study. Prior work done by Hutchison et al17 demonstrated a drastic decrease in DP prevalence between the first and second years of life, from 6.8 to 3.3%, respectively, thus indicating the possibility of natural skull correction over time. This decline in plagiocephaly over the first year of life is supported in the systematic review by Bialocerkowski et al, which showed DP rates peaking at 6 to 7 months and declining until 2 years of age.14

There is currently no research that quantifies the degree of correction in the first year of children’s lives. Prevalence has been shown to peak at 22.1% within the first 6 months of life,14 and incidence rates for children between 7 and 12 weeks old have been reported as high as 46.6%.18 These studies help illustrate the absence of agreement on the true prevalence or incidence of DP over the age range represented in our study. Establishing true prevalence of the condition is made even more complicated by the fact that DP in infants can vary depending on the clinician’s judgment as DP is not a standardized diagnosis and is generally left to the experience of the treating clinician. A lack of standardization is also reflected in our NAT and neglect cohorts, as diagnosis of abuse is often difficult and subjective. Our reliance on physician’s reports in the electronic medical record (EMR) to classify subjects, even if those diagnoses were made by a child abuse specialist, were susceptible to subjective variance.

Our technique for evaluating DP also could have contributed to the negative findings. Our method of assessing plagiocephaly involved calculating CVAI through the utilization of axial CT scans, and this process, while convenient for our study, has the potential to introduce some systematic error. In the literature, common methods of assessing DP include the Argenta scale19, optical three-dimensional imaging,20 21 anthropometric measurements using calipers21 plagiocephalometry,22 23 and the flexicurve.24 Among these various methods of plagiocephaly assessment, the CVAI has been shown to be a reliable method of evaluation, with prior studies affirming the use of visual assessments, flexicurve, and anthropometric measurements with calipers.13 22 24 That said, anthropometric measurements can involve the creation of outlines for head circumference,24 and we justified the use of CT scans as substitutes for these circumferential outlines. In choosing to apply the CVAI to CT scans, we assumed the results would be applicable to CVAI measurements via the different means listed earlier, particularly when CT scans are ordered for suspected abuse/head trauma. Also, it is important to note that the CVAI is not a perfect measurement of plagiocephaly even with in-person measurement, as detection of DP may fail to account for more complex malformations of the skull. Newer techniques have been proposed to accurately diagnose DP that involves mathematical models for assessing the entire calvarium.7

In addition to the above, our study was limited by sample size. Negative findings require significant power, and with a total of 76 subjects, we posit that a larger study would be necessary to confirm the lack of relationship between our studied variables. Our choice of methodology was partly responsible for the small sample size, as 320 of the 396 charts that met our inclusion criteria did not have available CT scans for evaluation. Future studies will likely require a prospective approach, as plagiocephaly is not often evaluated objectively in clinical settings, and the results of such evaluations are, in the authors’ experience, not formally recorded in the EMR. It is unusual that we found no demographic associations to neglect or NAT because factors such as age and SES have been correlated to rate and type of abuse in the literature.25 26 This absence of correlation likely stems from the aforementioned sample size as well as the fact that the median income for our families was between $46,000 and $50,000, well below the national average ($61,372 in 2017). Thus, we could not confirm the SES association with DP because our entire cohort was below the national average, so a stratification could not be created to appreciate the relationship between SES and DP in this study (Tables 4 5). Furthermore, our evaluation of SES was accomplished using U.S. census data on the median household income for the subject’s listed zip code of residence. This represents a relatively crude method of evaluating SES, and this type of categorization could have decreased the sensitivity of our methods.

Conclusion

In conclusion, the prevalence of DP within the NAT and neglect group was 23.7 and 18.4%, respectively, and the total prevalence within the combined NAT and neglect cohort was 21%. These percentages are consistent with the general rates of DP reported in the literature. DP did not prove to be predictive of either NAT or neglect. Future work will likely require a prospective approach, larger sample size, and a local control group to validate our findings. We hope the results of this work help guide future efforts to characterize trauma and plagiocephaly in the pediatric population.