Tight filum terminale syndrome in children: analysis based on positioning of the conus and absence or presence of lumbosacral lipoma

Background Tight filum terminale syndrome (TFTS) characterized by findings consistent with a tethered cord but with the conus ending in a normal position has only recently been observed in children. In this situation, diagnosis may prove difficult and sectioning of the filum terminale is questionable. Materials and methods Sixty cases of pediatric TFTS were analyzed by methods including spinal X-ray and magnetic resonance imaging (MRI). Twenty-one patients exhibited a normally positioned conus, 18 a low-lying conus, and 21 a low-lying conus with accompanying lumbosacral lipoma. These three groups were compared preoperatively and postoperatively for lumbosacral cutaneous stigmata, vertebral anomalies, concomitant congenital spinal dysraphisms, lower limb deformities, and sphincter dysfunction. Results Rates of occurrence of lumbosacral cutaneous stigmata and other concomitant congenital spinal dysraphisms differed significantly among the groups. Differences in other parameters were not observed. All groups responded positively to surgery. Conclusions Pediatric TFTS may involve a normally positioned conus. Diagnosis of pediatric TFTS should be based on clinical presentation, physical and radiological examinations, MRI, and pathologic changes in the filum. When neurological signs accompany such changes, early severing of the filum is indicated regardless of conus position.