Background/Aim: 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. Methods: 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. Results: 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. Conclusions: 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.

Object This work assessed the value of shunt series in the evaluation of children with CSF shunts, a test that is frequently ordered as part of the assessment of shunt integrity. Methods The medical records of all children who underwent shunt series at Children's Hospital of Eastern Ontario between 1975 and 2007 were reviewed. Ancillary studies that were performed within 2 days of the shunt series (brain CT, MR imaging, ultrasonography, and radionuclide shuntography) were noted, as well as the subsequent requirement for a shunt revision. Shunt series and ancillary studies were categorized as either positive (revealing an observable sign that a shunt-related problem was present, such as shunt discontinuity on the shunt series or enlargement of the ventricles on the brain CT scan) or negative (no clear sign of a shunt-related problem). Shunt series were further grouped into shunt series performed for diagnostic reasons, shunt series performed on a routine basis during follow-up in clinic, and shunt series performed postoperatively. The length of time between shunt insertion and shunt fracture was noted. Statistical analyses were performed, including the derivation of sensitivities and specificities. Results There were 3416 shunt series in 394 patients, of which 3004 were performed with ancillary studies. On average, patients underwent 9 shunt series, with a minimum of 1 and a maximum of 43, during the follow-up period (range 3 weeks to 19 years). A total of 2493 shunt series and ancillary studies (83%) yielded negative results and no surgery was performed. One hundred thirty shunts series were negative with a positive ancillary study (4.3%) and no surgery was required. In 8.7% (261 shunt series negative, ancillary studies positive) shunt revision surgery was necessary. The opposite trend was far less prevalent (17 shunt series positive, ancillary test negative; 0.6%) in which surgery was required. There were 87 patients with 96 shunt fractures (2.8% of shunt series). The average time between shunt insertion and shunt fracture was 7.9 years (range 3 months to 18 years). Shunt series had a sensitivity of 18% and a specificity of 97%. The ancillary studies had a sensitivity of 84% and a specificity of 85%. Conclusions The routine utilization of shunt series in the evaluation of a child with a CSF shunt is not necessary. This study showed that a very small number (0.6%) of shunt series helped in surgical decision making. Shunt series can be performed in selected cases, especially preoperatively in the absence of a baseline study to obtain information necessary for surgical planning.

Approximately one fourth of all shuntograms reported as normal are not (false-negative rate=25%). Review of five other major studies between 1980 and 2003 have reported false-negative rates between 2 and 36%, which may be explained by variations in shuntogram protocols. A standardized method is proposed.

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