Reappraisal of Pediatric Diastatic Skull Fractures in the 3-Dimensional CT Era: Clinical Characteristics and Comparison of Diagnostic Accuracy of Simple Skull X-Ray, 2-Dimensional CT, and 3-Dimensional CT

Are Complex Skull Fractures Indicative of Either Child Abuse or Major Trauma in the Era of 3-Dimensional Computed Tomography Imaging?

OBJECTIVE

The aim of the study was to determine whether complex skull fractures are more indicative of child abuse or major trauma than simple skull fractures.

DESIGN

This is a retrospective chart and imaging review of children diagnosed with a skull fracture. Subjects were from 2 pediatric tertiary care centers. Children younger than 4 years who underwent a head computed tomography with 3-dimensional rendering were included. We reviewed the medical records and imaging for type of skull fracture, abuse findings, and reported mechanism of injury. A complex skull fracture was defined as multiple fractures of a single skull bone, fractures of more than 1 skull bone, a nonlinear fracture, or diastasis of greater than 3 mm. Abuse versus accident was determined at the time of the initial evaluation with child abuse physician team confirmation.

RESULTS

From 2011 to 2012, 287 subjects were identified by International Classification of Diseases, Ninth Revision, code. The 147 subjects with a cranial vault fracture and available 3-dimensional computed tomography composed this study's subjects. The average age was 12.3 months. Seventy four (50.3%) had complex and 73 (49.7%) had simple fractures. Abuse was determined in 6 subjects (4.1%), and a determination could not be made for 5 subjects. Adding abused children from 2013 to 2014 yielded 15 abused subjects. Twelve of the abused children (80%) had complex fractures; more than the 66 (48.5%) of 136 accidentally injured children (P = 0.001; relative risk = 1.65 [1.21-2.24]). However, among children with a complex fracture, the positive predictive value for abuse was only 7%.

CONCLUSIONS

Complex skull fractures frequently occur from accidental injuries. This study suggests that the presence of complex skull fractures should not be used alone when making a determination of abuse.

Fracture-Associated Bruising and Soft Tissue Swelling in Young Children With Skull Fractures: How Sensitive Are They to Fracture Presence?

OBJECTIVES

The aim of this study was to determine how reliable scalp bruising and soft tissue swelling/cephalohematomas (STS) are for underlying young child skull fractures.

METHODS

This was a retrospective clinical and imaging review from 2011 to 2012 of children younger than 4 years with skull fractures from 2 tertiary care hospitals. Imaging was reread by 3 pediatric radiologists. Descriptive statistics were utilized. The retrospective review had institutional review board approval.

RESULTS

We identified 218 subjects for review: 210 unintentional and 8 abusive. One hundred forty-three had available 3-dimensional computed tomography reconstructions: 136 unintentional and 7 abused. Two-thirds were younger than 1 year. Twelve subjects had visible scalp bruising, but 73% had clinically and 93% radiologically apparent fracture-associated STS. There was no difference in clinical STS with simple (79%) versus complex (68%) fractures. Nor was there difference in subjects with fractures from minor (77%) versus major (70%) trauma. Unintentionally injured infants did not differ from abused for detectable STS (74% vs 50%). Parietal and frontal bones most frequently sustained fractures and most consistently had associated STS.

CONCLUSIONS

Clinically apparent STS is present in approximately three-fourths of children with skull fractures. It may not be important to consistently identify skull fractures in unintentionally injured children. Point-of-care ultrasound may be adequate. For abuse concerns, it is important to identify skull fractures as evidence of cranial impacts and intracranial hemorrhages. The most sensitive, widely available imaging technique, cranial computed tomography scan with 3-dimensional skull reconstruction, should be utilized. Scalp bruising is present in a minority of young children with skull fractures. Its absence does not exclude cranial impact injury.

Utility of three-dimensional and reformatted head computed tomography images in the evaluation of pediatric abusive head trauma

Skull fractures are common in the pediatric population following head trauma and are estimated to occur post head trauma in 11% of children younger than 2 years. A skull fracture indicates potential underlying intracranial injury and might also help explain the mechanism of injury. Multiple primary and accessory sutures complicate the identification of non-depressed fractures in children younger than 2 years. Detection of linear skull fractures can be difficult on two-dimensional (2-D) CT and can be missed, particularly when the fracture is along the plane of image reconstruction. Knowledge of primary and accessory sutures as well as normal anatomical variants is of paramount importance in identifying pediatric skull fractures with a greater degree of confidence. Acute fractures appear as lucent cortical defects that do not have sclerotic borders, in contrast to sutures, which might demonstrate sclerotic margins. Three-dimensional (3-D) CT has increased sensitivity and specificity for detecting skull fractures and is essential in the evaluation of pediatric head CTs for distinguishing subtle fractures from sutural variants, especially in the setting of trauma. In this review, we present our experience of the use of 3-D reformats in head CT and its implications on the interpretation, especially in the setting of accidental or abusive head trauma.

Biomechanical analysis of skull trauma and opportunity in neuroradiology interpretation to explain the post-concussion syndrome: literature review and case studies presentation

Traumatic head injuries are one of the leading causes of emergency worldwide due to their frequency and associated morbidity. The circumstances of their onset are often sports activities or road accidents. Numerous studies analysed post-concussion syndrome from a psychiatric and metabolic point of view after a mild head trauma. The aim was to help understand how the skull can suffer a mechanical deformation during a mild cranial trauma, and if it can explain the occurrence of some post-concussion symptoms. A multi-step electronic search was performed, using the following keywords: biomechanics properties of the skull, three-dimensional computed tomography of head injuries, statistics on skull injuries, and normative studies of the skull base. We analysed studies related to the observation of the skull after mild head trauma. The analysis of 23 studies showed that the cranial sutures could be deformed even during a mild head trauma. The skull base is a major site of bone shuffle. Three-dimensional computed tomography can help to understand some post-concussion symptoms. Four case studies showed stenosis of jugular foramen and petrous bone asymmetries who can correlate with concussion symptomatology. In conclusion, the skull is a heterogeneous structure that can be deformed even during a mild head trauma.

Classification of tibial plateau fractures using 3DCT with and without subtraction of unfractured bones

BACKGROUND

The addition of 3D CT scans for observers evaluating tibial plateau fractures decreases agreement and diagnostic accuracy, possibly due to obstruction of the view by unfractured bones (i.e., patella, fibula, and femur) in 3D reconstructions.

QUESTIONS/PURPOSES

This study compared (1) the interobserver agreement between (subgroups of) observers classifying 3DCT reconstructions of tibial plateau fractures according to Schatzker, Luo, and AO/OTA, (2) recognition of different fracture characteristics, and (3) the level of confidence on a scale from 0 to 10 with and without subtraction of the unfractured bones.

METHODS

We selected twenty consecutive 3DCT reconstructions of tibial plateau fractures treated in a level I trauma center between 2013 and 2014. Members of the Science of Variation Group were randomized (1:1) to evaluate reconstructions with or without subtraction of the unfractured bone. Forty-nine surgeons completed the survey. The interobserver agreement was determined using Fleiss' kappa, and bootstrapping (resamples = 1000) was used to calculate the standard error, z statistic, and confidence intervals.

RESULTS

Overall, subtraction of unfractured bones did not affect interobserver agreement in Schatzker, Luo, and AO/OTA classification systems, agreement on the presence of fracture characteristics, and level of confidence. In subgroup analysis, non-trauma surgeons had significantly higher agreement in the three classification systems with subtraction. For fracture characteristics, some subgroups had higher agreement while others had lower agreement with subtraction.

DISCUSSION

The finding that agreement on classification of tibial plateau fractures is limited on 3DCT scan and is not improved by subtraction of unfractured bones suggests that disagreement may be based on variations in understanding and bias. Reliability of these classification systems might benefit from a focus on accounting for these pre-existing conceptualizations rather than further emphasis on imaging detail.

LEVEL OF EVIDENCE

Diagnostic, level 1.

Avoiding skull radiographs in infants with suspected inflicted injury who also undergo head CT: "a no-brainer?"

Objectives

To assess whether head CT with 3D reconstruction can replace skull radiographs (SXR) in the imaging investigation of suspected physical abuse (SPA)/abusive head trauma (AHT).

Methods

PACS was interrogated for antemortem skeletal surveys performed for SPA, patients younger than 2 years, SXR and CT performed within 4 days of each other. Paired SXR and CT were independently reviewed. One reviewer analysed CT without and (3 months later) with 3D reconstructions. SXR and CT expert consensus review formed the gold standard. Observer reliability was calculated.

Results

A total of 104 SXR/CT examination pairs were identified, mean age 6.75 months (range 4 days to 2 years); 21 (20%) had skull fractures; two fractures on CT were missed on SXR. There were no fractures on SXR that were not seen on CT. For SXR and CT, respectively: PPV reviewer 1, 95% confidence interval (CI) 48–82% and 85–100%; reviewer 2, 67–98% and 82–100%; and NPV reviewer 1, 95%, CI 88–98% and 96–100%; reviewer 2, 88–97% and 88–98%. Inter- and intra-observer reliability were respectively the following: SXR, excellent (kappa = 0.831) and good (kappa = 0.694); CT, excellent (kappa = 0.831) and perfect (kappa = 1). All results were statistically significant (p < 0.001).

Conclusions

CT has greater diagnostic accuracy than SXR in detecting skull fractures which is increased on concurrent review of 3D reconstructions and should be performed in every case of SPA/AHT. SXR does not add further diagnostic information and can be omitted from the skeletal survey when CT with 3D reconstruction is going to be, or has been, performed.

Key Points

• Head CT with 3D reconstruction is more sensitive and specific for the diagnosis of skull fractures.

• Skull radiographs can be safely omitted from the initial skeletal survey performed for suspected physical abuse when head CT with 3D reconstruction is going to be, or has been, performed.