When is a Skeletal Survey Used?
A skeletal survey is indicated for all children younger than 24 months (2 years) of age when there is any suspicion of physical abuse, regardless of whether neurologic or visceral injuries are clinically apparent. 1
Primary Age-Based Indications
Children Under 24 Months
- Skeletal survey is recommended in all children <2 years of age with suspected abuse because 80% of abused children with fractures are <18 months of age, and the majority of positive skeletal surveys occur in children <1 year of age 1
- Fractures occur in up to 55% of physically abused children, making skeletal survey the initial imaging modality of choice 1
- 11-20% of infants undergoing evaluation for abuse have an unsuspected fracture detected by skeletal survey that would otherwise remain undiscovered 1
- In one large study of 567 infants, 21% had positive skeletal surveys with previously unsuspected fractures 2
Children 24 Months to 5 Years
- Skeletal surveys may be appropriate in some children between ages 2 and 5 years, depending on the clinical suspicion of abuse 1
- In older children, it is usually more appropriate to target imaging to specific areas of suspected injury rather than performing a complete skeletal survey 1
Clinical Scenarios Requiring Skeletal Survey
High-Risk Presentations
- Children <6 months of age with bruising have a high incidence of additional injuries and warrant skeletal survey 1
- Infants with isolated bruises (seen in 146 children in one study) had new injury on skeletal survey in 27% of cases 1
- Children presenting with head injury (skull fracture or intracranial injury), known skeletal fractures, or bruising in suspicious locations 3
Specific Fracture Patterns That Trigger Evaluation
- Highly specific fractures for abuse include posterior rib fractures, classic metaphyseal lesions, epiphyseal separation injuries, and avulsive fractures of the acromion process 1
- Fractures of the radius, ulna, tibia, fibula, or femur in children <1 year of age 1
- Femoral fractures in a child who is not yet walking 1
- Unexplained humeral fractures in children <15 months of age 1
- Multiple fractures in any location without overt trauma 1
Family Contacts of Abused Children
- Pediatric contacts of abused children, especially twins, may need screening by skeletal survey 1
- In one study, 17% of siblings (particularly twins) of index abuse cases had positive skeletal surveys 3
Follow-Up Skeletal Survey Protocol
Timing and Indications
- A repeat skeletal survey should be performed approximately 2-3 weeks after the initial examination when abnormal or equivocal findings are found on the initial study and when abuse is suspected on clinical grounds 1
- After a negative initial survey, 9-12% of infants have healing fractures on follow-up survey 1, 4
- Up to one-third of follow-up surveys yield new information, with half to three-fourths being rib fractures 1, 4
Modified Follow-Up Protocol
- To limit radiation exposure, the follow-up examination may be limited to 15 views by omitting views of the skull, pelvis, and lateral spine if no injury was initially seen in these regions 1
- The total estimated effective radiation dose for both initial and follow-up skeletal surveys is approximately 0.26 mSv, equivalent to 1 month of UK background radiation 5
Technical Requirements for Skeletal Survey
Standard Protocol Components
- The skeletal survey should include 21 images: frontal and lateral views of the skull, lateral views of the cervical and thoracolumbosacral spine, single frontal views of the long bones, hands, feet, chest, and abdomen 1
- Oblique views of the ribs are essential to increase accuracy of diagnosing rib fractures, which may be the only skeletal manifestation of abuse in 30% of physically abused infants 1
- Images should be obtained using high-detail imaging systems and coned to specific areas of interest, with separate views of each arm, forearm, thigh, leg, hand, and foot 1
Common Pitfalls to Avoid
- Do not substitute bone scintigraphy for skeletal survey as the primary imaging modality; bone scan is complementary/adjunctive only and should be used when skeletal survey is negative but clinical suspicion remains high 1
- Bone scan has limitations: it may miss skull fractures and classic metaphyseal lesions, requires venipuncture and often sedation, and cannot date fractures accurately 1
- Do not rely on the presence or absence of bruising associated with fractures to determine if abuse occurred; the majority of children with fractures do not have associated bruising 1
- Fractures may be missed if imaging guidelines are not followed or if images are of poor quality 1
Integration with Other Imaging
Head Imaging Considerations
- Clinicians should have a relatively low threshold for performing CT or MRI of the head in children with suspected abuse, as 29-37% of children <12 months with suspected abuse but no clinical signs of head injury have positive neuroimaging 1
- Unenhanced CT of the head is the examination of choice for initial evaluation of intracranial injury in child abuse 1