Role of ultrasonography in screening of spinal dysraphism in infants at risk

Background Spinal dysraphism (SD) encompasses congenital spinal defects that result from inappropriate fusion of the different midline osseous, mesenchymal, and neural elements. The primary tools for diagnosis of SD are both spinal ultrasonography (USG) and magnetic resonance imaging (MRI). Spinal USG is growingly being used as an initial screening modality with sensitivities and accuracies equivalent to those of MRI. Anorectal malformations (ARM) have ultimate association with many other congenital abnormalities, of which spinal dysraphism is one of the most common. The main aim of study was to assess the diagnostic accuracy of spinal USG as a screening modality in comparison with MRI in infants with closed spinal dysraphism. We also endeavored to highlight the associated spinal dysraphism radiological findings in patients with either ARM or back cutaneous stigmata. Results Our prospective diagnostic comparative study included 33 patients, all of whom underwent both MRI and USG. Both MRI and USG showed appreciable agreement in the assessment of spinal dysraphism. In comparison with the gold standard MRI, spinal USG revealed comparable diagnostic metrics: specificity (98.6–100%), sensitivity (66.6–91.6%), PPV (90–100%) and NPV (94.1–98.7%) in diagnosis of different types of spinal dysraphism. The main clinical presentation of nineteen patients was anorectal malformation (ARM), 11 of whom (57.9%) had evidence of associated spinal dysraphism. The most common types of ARM were cloacal malformation, recto-urethral fistula, and rectal atresia with no fistula. On the other hand, sixteen patients were mainly presented with back cutaneous stigmata, 11 of whom (68.8%) had associated spinal dysraphism. The most common presenting cutaneous stigmata were low back swelling and atypical dimples. Conclusion The front-line screening modality for infants with closed SD should be spinal USG, however, its main limitation is the restrained time window in the first 6 months of life. Infants with ARM should be screened for spinal anomalies, especially those with high and complex types. Infants with high-risk back cutaneous stigmata should be similarly screened, as well.