Ultrasound investigation of sacral dimples and other stigmata of spinal dysraphism

Objective To assess whether there was any relationship between the number of clinical markers for spinal dysraphism and its presence on ultrasound and whether there was any relationship between the presence of an isolated sacral dimple and the presence of spinal dysraphism. Outcomes and further imaging were also examined. Methods All patients who underwent spinal ultrasound (SUS) in University Hospital Galway (UHG) over a 5-year period (2006-2011) were identified. Patients were excluded based on age (>14 years old excluded) and indication for imaging (only patients being investigated for suspected spinal dysraphism were included). Indications for imaging, ultrasound results and information on further imaging were accessed from the computerised radiology software in UHG. Statistical analysis was performed using SPSS-18. Results Data were analysed for 216 patients. A single clinical indication was recorded for 174 ultrasound requests, >= 2 indications for 42 requests. Nineteen of 216 (8.8%) ultrasound images were abnormal, 7 having spinal dysraphism. Multiple clinical indications were 6 times more likely to have dysraphism than those imaged on the basis of a single marker (OR 6.0, 95% CI 1.289 to 27.922, p=0.022), and there was no significant correlation between the presence of a sacral dimple and the presence of dysraphism (95% CI 0.71 to 6.622, p=0.722). Conclusions SUS performed on the basis of multiple clinical indications is six times more likely to detect spinal dysraphism than imaging performed for isolated abnormalities or risk factors. Sacral dimple is a poor marker for occult spinal pathology.