G. A. Metzger18, J. N. Cooper18, R. S. Kabre1, G. Z. Mak2, D. R. Halleran18, K. Boyd3, S. Chan4, D. Corea5, P. Dydynski6, K. Gill7, S. Kraus8, R. Sanchez9, A. Afrazi10, C. Calkins11, C. Downard12, P. Ehrlich13, J. D. Fraser14, M. Landman15, C. Leys20, B. Rymeski17, R. J. Wood21, M. A. Levitt21, K. J. Deans18, G. Bates19, P. C. Minneci18 20University of Wisconsin School of Medicine and Public Health,Pediatric Surgery,Madison, WI, USA 21Nationwide Children’s Hospital,Pediatric Colorectal And Pelvic Reconstructive Surgery,Columbus, OH, USA 1Ann & Robert H. Lurie Children’s Hospital of Chicago,Pediatric Surgery,Chicago, IL, USA 2The University of Chicago Medicine and Biologic Sciences,Pediatric Surgery,Chicago, IL, USA 3Children’s Hospital Of Wisconsin,Pediatric Radiology,Milwaukee, WI, USA 4Children’s Mercy Hospital- University Of Missouri Kansas City,Pediatric Radiology,Kansas City, MO, USA 5Indiana University School Of Medicine,Radiology,Indianapolis, IN, USA 6University Of Louisville,Pediatric Radiology,Louisville, KY, USA 7University of Wisconsin School of Medicine and Public Health,Pediatric Radiology,Madison, WI, USA 8Cincinnati Children’s Hospital Medical Center,Radiology,Cincinnati, OH, USA 9University Of Michigan,Pediatric Radiology,Ann Arbor, MI, USA 10Children’s Hospital Of Pittsburgh Of UPMC,Pediatric Surgery,Pittsburgh, PA, USA 11The Medical College of Wisconsin,Pediatric Surgery,Milwaukee, WI, USA 12University Of Louisville,Pediatric Surgery,Louisville, KY, USA 13University Of Michigan,Pediatric Surgery,Ann Arbor, MI, USA 14Children’s Mercy Hospital- University Of Missouri Kansas City,Pediatric Surgery,Kansas City, MO, USA 15Indiana University School Of Medicine,Pediatric Surgery,Indianapolis, IN, USA 17Cincinnati Children’s Hospital Medical Center,General And Thoracic Surgery And The Colorectal Center,Cincinnati, OH, USA 18Nationwide Children’s Hospital Center for Surgical Outcomes Research,Pediatric Surgery,Columbus, OH, USA 19Nationwide Children’s Hospital,Pediatric Radiology,Columbus, OH, USA
On behalf of the Midwest Pediatric Surgery Consortium
Introduction:
Anorectal malformations (ARMs) are a spectrum of congenital anomalies with varying prognosis for fecal continence based on the involved anatomy and presence of other associated anomalies. Although long-term fecal continence is the goal of surgical therapy; the ability to predict an infant’s potential for fecal continence later in life remains a challenge. The sacral ratio (SR) is a measure of sacral development that has been proposed as a measurement that can help predict future fecal continence in children with ARM. The use of SR as a relevant clinical adjunct is dependent upon its reproducibility across different institutions, and it should be accurate and consistent when measured by different radiologists. The aim of this study was to quantify the inter-rater reliability of sacral ratio calculations by comparing the results of images read by radiologists at different institutions.
Methods:
The sacral ratio was measured using a standardized method. X-rays in the anteroposterior (AP) and lateral planes were obtained from patients at six children’s hospitals. Images were then deidentified and reviewed by a single pediatric radiologist at each of the six institutions. Subsequently, all x-rays from each site were reviewed by a single, central radiologist. Inter-rater reliability (IRR) was assessed by calculating Pearson correlation coefficients and intra-class correlation coefficients (ICC) from linear mixed models with patient and rater-level random intercepts.
Results:
In total, imaging from 263 patients was included in the study. 255 AP sacral images and 103 lateral sacral images were reviewed. The number of patients at each participating site ranged from 17 to 69. The patient population was 56.7% male and 79.5% Caucasian. The most common anomaly present was perineal fistula (34.6%). The mean inter-rater absolute difference in the AP sacral ratio was 0.05 (IQR 0.02-0.10), and in the lateral sacral ratio was 0.16 (IQR 0.06-0.25). Overall, inter-rater reliability was excellent for AP sacral ratios (ICC 81.5%, 95% CI 75.1-86.0%) and poor for lateral sacral ratios (ICC 44.0%, 95% CI 29.5-59.2%). For both AP and lateral sacral ratios, ICCs were similar when examined by type of radiograph used for calculation, severity of the ARM, presence of sacral or spinal anomalies, and age at imaging.
Conclusion:
Across radiologists, the reliability of sacral ratio calculations was excellent for the AP sacral ratio but poor for the lateral sacral ratio. These results suggest that better standardization of lateral SR measurements is needed if they are going to be used to counsel families of children with ARM.
