Occult spinal dysraphism in neonates: assessment of high-risk cutaneous stigmata on sonography.

OBJECTIVE

In this study, we evaluated the incidence of dorsal cutaneous stigmata in a healthy neonate population; we also assessed whether specific types of cutaneous stigmata are associated with underlying spinal dysraphism.

SUBJECTS AND METHODS

From July 1993 through December 1996, we prospectively examined term neonates with dorsal cutaneous stigmata. Each neonate underwent spinal sonography and clinical assessment of the cutaneous stigmata. Incidence of dorsal cutaneous stigmata in a healthy neonatal population was determined by dividing the number of neonates with cutaneous stigmata by the total number of neonates examined.

RESULTS

The incidence of cutaneous stigmata in the healthy neonate study population was 4.8%. We examined 207 neonates with 216 cutaneous stigmata, the most common of which was the simple midline dimple (74%). None of the neonates with only a simple midline dimple had spinal dysraphism. Of the 207 neonates we examined, 16 had spinal dysraphism. Clinical examination revealed 180 dimples and 36 other types of cutaneous stigmata (e.g., hemangiomas, hairy patches, masses, tails, lesions). Fourteen (39%) of 36 other cutaneous stigmata were positive for spinal dysraphism. Eight (40%) of 20 atypical dimples were positive for spinal dysraphism. Three were large clefts (>5 mm); the remaining five cases were seen in combination with other lesions and were all located more than 2.5 cm from the anus. Six (67%) of the nine neonates with multiple cutaneous stigmata had spinal dysraphism.

CONCLUSION

Simple midline dimples are the most commonly encountered dorsal cutaneous stigmata in neonates and indicate low risk for spinal dysraphism. Only atypical dimples are associated with a high risk for spinal dysraphism, particularly those that are large (>5 mm), high on the back (>2.5 cm from the anus), or appear in combination with other lesions. High-risk cutaneous stigmata in neonates include hemangiomas, upraised lesions (i.e., masses, tails, and hairy patches), and multiple cutaneous stigmata.