"Inappropriate" spinal ultrasounds for suspected occult spinal dysraphism

Spinal ultrasound is used to investigate occult dysraphism in neonates with sacrococcygeal dimples. Inappropriate imaging studies may be performed despite the Choosing Wisely Canada guidelines. The objective of this study was to assess the appropriateness of spinal ultrasounds performed in 2 Canadian provinces and to compare the diagnostic accuracy of spinal ultrasound and MRI in predicting the need for neurosurgical intervention.

This multicenter retrospective cohort study identified spinal ultrasounds in neonates younger than 6 months of age from January 1, 2017, to December 30, 2018, in Alberta and British Columbia, Canada. The authors collected data on patient demographic characteristics, reasons for requested imaging, the presence of any imaging abnormalities, and the ultimate need for intraspinal surgery. Ultrasounds were deemed appropriate if the Choosing Wisely guidelines were followed for ordering. The authors compared high-risk findings on spinal ultrasound and MRI to the need for surgery using sensitivities, specificities, positive predictive values (PPV), and negative predictive values (NPV).

A total of 1043 ultrasounds were ordered in 1042 neonates, most commonly by pediatricians (49%), family doctors (27%), and neonatologists (16%). Three hundred eighty-three ultrasounds (37%) were deemed inappropriately ordered. Sixty-nine infants (7%) of the cohort received an MRI and 11 (1%) ultimately underwent neurosurgical intervention. None of the patients who had an inappropriately ordered ultrasound underwent surgery. Spinal ultrasound, compared to surgery, had a sensitivity of 36%, specificity of 98%, PPV of 17%, and NPV of 99%. Spinal MRI, compared to surgery, had a sensitivity of 73%, specificity of 76%, PPV of 38%, and NPV of 94%.

Although spinal ultrasound has an acceptable specificity in predicting surgery, it remains a poor screening test (36% sensitivity). Given that approximately 37% of spinal ultrasounds were inappropriately ordered in this study period, the authors estimate that if physicians followed the Choosing Wisely Guidelines more closely, it would result in an estimated potential cost savings of CAD$1,856,769 over a decade for Canada with minimal surgical impact and a very low risk of missing surgically relevant spinal dysraphism.