The second skeletal survey earns its radiation

Design

single-centre retrospective audit against national safeguarding guidance, no comparison group

Population

168 children under 2 years having two skeletal surveys at the Children's Hospital for Wales, January 2018 to February 2025

Primary outcome

adherence to the two-survey protocol within 14 days, and fracture yield on primary versus secondary survey

Effect

additional fractures on primary survey 10/168 (6.0%), on secondary survey 12/168 (7.1%), found solely on secondary survey 1/168 (0.6%)

UK safeguarding guidance from 2018 asks for two skeletal surveys within two weeks in children under two: a full survey first, with CT head if under one year, then a secondary survey using selected views of the chest and long bones. Recent work questioned whether the yield justified a second dose of ionising radiation. This retrospective audit at the Children's Hospital for Wales tested that against seven years of practice.

Of 186 children imaged between January 2018 and February 2025, 168 were under two and had both surveys, and 95.8% of second surveys were done inside the fourteen days. Presentations were mostly bruising or skin lesion (106), then fracture (43), domestic violence (15), a sibling's fracture (2) and head injury (2). Fractures additional to the presenting injury were found on the primary survey in 10 of 168 children (6.0%), and on the secondary survey in 12 of 168 (7.1%). In 1 child (0.6%), the primary survey was normal and a fracture was found only on the second.

So the second survey found additional injuries slightly more often than the first did - a yield that is hard to argue away, in a group where a missed fracture is a child returned to danger. The 0.6% figure is the one to be careful with: only one child had a wholly normal first survey, so the argument for the second survey rests mainly on it adding to an already abnormal picture, which changes the strength of the safeguarding case rather than creating it. This is a single-centre audit without a comparison group, and it supports continuing the existing protocol rather than establishing it anew.

• Keep both surveys and keep the second inside fourteen days - adherence here was 95.8%, which is what makes the yield interpretable.
• Expect the second survey to add findings in about one in fourteen children, more often than not to an already abnormal first survey.
• Do not let a normal primary survey close the safeguarding question before the second is done.
• Remember the commonest referral reason was a bruise or skin lesion, not a fracture - the pathway starts at the front door.
• Where the protocol is not established, note that this is single-centre audit evidence supporting an existing guideline rather than a trial.

The statistics, in plain English

These are proportions from a single centre with no comparison group, so they describe yield rather than measure a benefit. The two numbers being close - 6.0% on the first survey and 7.1% on the second - is the argument, because it shows the second survey is not scraping a nearly empty barrel. But 12 of 168 and 10 of 168 differ by two children, which is well inside what chance would produce; the honest claim is that the yields are comparable, not that the second is higher. The 1 in 168 with a normal first survey and an abnormal second is a single case, and no conclusion about frequency can rest on it.

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