Duration of horizontal decubitus after section of a tight filum terminale as a means to prevent cerebrospinal fluid leakage

OBJECT: The untethering of a tethered spinal cord by transecting a tight filum terminale is a relatively simple surgical procedure that can prevent or ameliorate neurological symptoms. Postoperatively patients are usually kept flat in order to prevent a cerebrospinal fluid (CSF) leak. However, the optimal period of maintaining patients flat has not been determined yet. The authors present their experience, compare with ones of previous reports, and try to determine the optimal period. METHODS: We retrospectively analyzed surgical results of pediatric patients with tethered spinal cord by a tight filum terminale. The patients' charts were reviewed for demographic data, clinical presentation, surgical therapy, and clinical course. RESULTS: One hundred-sixty-one patients underwent sectioning of a tight filum terminale. They all were kept lying flat for 8 days. Magnetic resonance imaging (MRI) was performed 10 to 14 days after the surgery. None of the patients developed a CSF leak. Pseudomeningocele, which was confirmed by MRI, developed in one patient (0.6%). The occurrence rate of a CSF leak was significantly lower in our series than that of previous reports in which patients maintained flat less than 72 hours (P = 0.0069). CONCLUSION: To keep patients flat for a longer time after transection of a tight filum terminale seems to lower the rate of CSF leakage and psuedomeningocele.