Spinal cord detethering in children with tethered cord syndrome and Chiari type 1 malformations.

We discuss the association between tethered cord syndrome (TCS) and Chiari type 1 malformation (CM1), and report on the surgical outcomes of children with CM1 and TCS who underwent sectioning of the filum terminale (SFT). The relationship between TCS and CM1 is unclear. A retrospective review of 170 consecutive spinal cord detetherings between 2008 and 2012 was performed. We identified 17 children with CM1 who underwent SFT. Information regarding clinical presentation, radiographic findings, surgical procedures, and clinical outcomes was analyzed. A mean tonsillar herniation of 10.0mm (range: 5-21) was noted. Children with a fatty or thickened filum terminale demonstrated a greater amount of tonsillar displacement (p<0.005). A low conus medullaris was found in 12 children and a syrinx was present in three. The preoperative symptoms improved in all children. The postoperative MRI (mean 21.8 months) revealed an unchanged tonsillar position in all but one child. No worsening of neurologic function was noted. Pediatric patients who have both CM1 and TCS, but do not demonstrate classic Chiari-related symptoms, may experience symptomatic improvement after filum terminale sectioning.