The study is based on retrospective analysis of patient data in two trauma centres in Germany: The first (C1) is a university hospital in Greifswald, a city with a rural catchment area and a population of 57,985 in 2016. The second (C2) is a dedicated trauma centre located in Berlin, a city with a population of 3,574,830 in 2016. We searched the picture archiving and communication system (PACS) for patients that received a WBCT and reviewed the clinical information of the corresponding cases. A WBCT would be performed for the same indication at both centres and according to the German guidelines for the treatment of severely injured patients, including patients with impaired consciousness and suspected trauma history [2].
Patients were included in this study if no previous instrumental diagnostics had been performed and if a tracheal tube was visible in the WBCT, eliminating patient dependent clues and focusing on manual and instrumental diagnostics. WBCT cases for follow-up and for non-traumatic reasons were excluded from the study.
In C1 we identified 939 WBCT cases during the survey period from 1 Jan 2013 to 31 Dec 2015 and in C2 we found 1887 between 1 Jan 2014 and 31 Dec 2015, totalling 2826 cases. Of 535 intubated patients, 426 had a history of suspected or observed trauma and were included. Sixty six patients showed a total of 132 fractures of hand and/or forearm.
For every patient, sex, age, and diagnoses were collected. The Injury Severity Score (ISS) was calculated using AIS 2005 (Update 2008).
The radiology report of the WBCT scan as well as all following medical procedures and corresponding reports of the patient until discharge were analysed for injuries of hand or forearm (phalanges, metacarpal and carpal bones, radius and ulna).
In case of injuries of the hand or forearm, the type of injury, diagnostic modality, clinical description, and time to diagnosis were recorded. We reviewed the admission and discharge documents for clinical symptoms like swelling, bruises, wounds or other pathological findings of the hand and forearm.
We analysed whether fractures were identified through WBCT and set two categories for the time to identification by WBCT or X-ray: “early” within 24 h after admission and “late” after 24 h.
In both centres, the WBCT was performed with contrast agent using a 64-slice device. The radiological report was written by the radiologist on duty and reviewed by a senior radiologist usually within 24 h. The time between first and second assessment, and the years of experience of the radiologists were not available.
For this study, the CT scans were reviewed for position of the hands and forearms and their inclusion in the scan field. If a bone was not fully visible in his entirety, the area was marked as incomplete. The border between the hand and forearm was defined at the radiocarpal joint. Arm position was categorised depending on the location of the hand which could be on the trunk, on the thighs distal of the inguinal ligament, next to the patient, and other.
Quantitative values are shown with median (range).
For sensitivity analysis, the WBCT report on admission was considered the index test. The reference was all known diagnoses on discharge of the patient. True positive was the number of cases with reported fractures in the WBCT. False negative was the number of fractures that were detected later than 24 h after admission. Sensitivity was calculated by dividing the number of true positive cases by the sum of true positive and false negative cases. We did not test for false positive cases. Ninety percent confidence intervals (CI) were calculated using Clopper-Pearson Exact.
Variables were tested for normal distribution using the Shapiro-Wilk test. As it showed a normal distribution only for subgroups, independent continuous variables were tested using Mann-Whitney-U test. Statistical tests of categorial variables with at least 5 expected cases for each field were performed with Chi-square, and Fisher’s exact for tables that did not meet the requirement. A p-value of ≤0.05 was defined as significant.