Evaluating the Diagnostic Utility of Spinal Ultrasound in Neonates With a Simple Sacral Dimple: An Eight-Year Retrospective Study

Abstract

INTRODUCTION: Spinal dysraphism describes a spectrum of congenital anomalies pertaining to the spine and spinal cord. Ultrasound is the preferred imaging modality for diagnosing dysraphism in low-risk neonates due to its cost-effectiveness and availability. Recent research demonstrates a low incidence of dysraphism in infants with an isolated sacral dimple and associated cutaneous stigmata (e.g., hairy tuft, haemangioma). We sought to determine the number of neonates referred for investigation of a simple sacral dimple, and the proportion found to have dysraphism. METHODS: A retrospective analysis of the radiology information system was performed in a quaternary Australian children's hospital. Children undergoing spinal ultrasound from January 2016 to November 2024 were included. Patients over 90 days of age, and with indications other than simple sacral dimple were excluded. RESULTS: There were 448 spinal ultrasound examinations reviewed; of these, 195 (43.5%) were for a simple sacral dimple. Mean age at scan was 33 days (range 2-90 days, sd = 24 days), 88 (45.1%) were female. Only two (1.0%) were diagnosed with dysraphism; both were found to have tethered cords. Both patients were subsequently diagnosed with concomitant anomalies (cardiac, and a Dandy Walker Malformation). CONCLUSION: Our findings support literature suggesting ultrasound screening for neonates with a simple sacral dimple has a very low diagnostic yield.