Sectioning of the filum terminale is performed when spinal cord tethering is suspected, sometimes without clinical symptoms. Retethering can occur and require reoperation due to the presentation of either recurrent or new symptoms. The purpose of this institutional review was to identify the retethering rate in children, especially in those who were initially asymptomatic, and to discuss the role of surgery.
The medical records of all children at the Children's Hospital of Eastern Ontario (CHEO) who underwent tethered cord surgery between 1978 and 2009 for a thickened filum terminale were retrospectively reviewed, as well as those who retethered.
A total of 146 patients with a mean age of 4.3 years underwent a low lumbar single or partial laminectomy for sectioning of the filum terminale; 44 patients (30.1%) were asymptomatic at the time of surgery, 51.4% had bladder and bowel dysfunction, 26.7% had neuroorthopedic findings, 15.8% had pain and 6.2% had progressive scoliosis; 11 children with a median age of 8.9 years had symptoms of retethering requiring reoperation (median time to retether was 4.3 years) and 4 were initially asymptomatic. Repeat surgery was successful at alleviating the new symptoms that occurred as a result of retethering.
Of the 146 patients at CHEO who underwent surgery, 7.5% retethered, with 36% being initially asymptomatic. Those operated in the first year of life were not found to be at a higher risk. The level of the conus medullaris did not influence the rate or retethering or urological dysfunction. Children who were initially asymptomatic improved after surgery for retethering, but may not have required surgery in the first place.