Sonography of the caudal spine and back: Congenital anomalies in children

Articulated-arm, B-mode 3.5-5.0 MHz sonograms from 27 children with congenital anomalies of the caudal spine were analyzed retrospectively and correlated directly with patient appearance, preoperative myelograms, intraoperative photographs, and pathologic specimens to determine how effectively sonography could display the major pathologic features known to be present. Anterior spina bifida, posterior spina bifida, and (partial) sacral agenesis were displayed as focal absence of normal spinal echoes and distortions of the paraspinal/gluteal muscles. Subcutaneous anechoic spaces continuous with the spinal canal through a spina bifida identified the presence, site, and configuration of each meningocele present. Highly echoic masses were easily discerned at the sites of 14 of 16 lipomas and at the solid fibroadipose portions of both sacrococcygeal teratomas. Echoes from the surface of the spinal cord and occasionally from the central canal identified abnormally low cord position in 16 of 17 cases and identified herniation of the cord (or filum) into a concurrent meningocele in seven of 10 cases. Sonographic display of an anechoic meningocele bordered by a lobular, highly echoic, subcutaneous lipoma that inserted onto a low-lying or herniated spinal cord reliably identified lipomyelomeningocele. Despite limitations discussed in the text, initial experience suggests that sonography will be a useful method for screening patients for possible tethered spinal cord, (lipo)(myelo)meningocele, sacrococcygeal teratoma, and other anomalies of the caudal spinal axis.