Magnetic resonance imaging of postrepair-myelomeningocele--findings in 31 children and adolescents

Retethering of transected fatty filum terminales

OBJECT

Untethering of a tethered spinal cord (TSC) by transecting or removing a fatty filum terminale is a relatively simple procedure that can prevent or ameliorate neurological symptoms, and the postoperative prognosis is usually good. Progressive neurological deterioration caused by recurrent tethering has been rarely reported. The authors present their experience in cases in which a sectioned fatty filum terminale has become retethered.

METHODS

The authors retrospectively analyzed the surgical results of pediatric patients with fatty filum terminale-TSC treated by transection of the filum. The patients' charts were reviewed for demographic data, clinical presentation, surgical therapy, and follow-up data.

RESULTS

Of the 225 children who underwent TSC release by sectioning the fatty filum from 1992 to 2005, there were 6 patients (2.7%; 3 males, 3 females) in whom the fatty filum retethered. The mean age at the first diagnosis of TSC was 5.2 years (range 2 months-12.3 years). The mean duration from the first untethering procedure to retethering was 5.4 years. The mean age at the time of retethering was 10.6 years (range 7-17.5 years). Symptoms of retethering were urinary incontinence, low-back pain, difficulty walking, constipation, leg pain, and worsening foot deformity. Patients underwent cystometrography at the time retethering was indicated by increased bladder capacity, large post-void residual volume, decreased bladder capacity, increase in filling pressure, and poor sensation of filling. Magnetic resonance imaging revealed adherence of the rostral stump of the sectioned filum to the midline dorsal dural surface. All patients underwent the second untethering procedure. Four patients improved neurologically and experienced no retethering thereafter (mean follow-up period 5.5 years). Two patients experienced additional retethering after temporary improvement following the second untethering procedure.

CONCLUSIONS

Retethering of the spinal cord is a rare condition occurring after the sectioning of a fatty filum terminale. Awareness of this rare sequela is necessary for appropriate long-term management of TSC caused by a fatty filum terminale. Cystometrography is useful for detecting the lesion and confirming the diagnosis of retethering.

Retethering of sectioned fibrolipomatous filum terminales: report of two cases

OBJECTIVE AND IMPORTANCE

The release of a tethered spinal cord by sectioning a thickened filum terminale is a straightforward surgical procedure that can prevent, arrest, or ameliorate neurological deficits. We recently recognized progressive neurological deterioration caused by filum retethering in two patients years after this procedure was performed. This sequela of a recurrent tethered cord after the sectioning of a filum terminale has not previously been described.

CLINICAL PRESENTATION

Two female patients, each 13 years of age at presentation, had been previously operated on for tethered spinal cords secondary to fibrolipomatous (fatty) fila terminale. Both presented with bladder dysfunction and one with progressive paraparesis. Magnetic resonance images revealed a low-lying conus medullaris and a sectioned filum with the proximal stump adherent to the posterior dura.

INTERVENTION

Each patient underwent neurosurgical exploration of the previous site of sectioning, with the recognition of a retethered proximal stump of the filum terminale. After rerelease of the fatty filum, the patient with only bladder dysfunction stabilized and a motor examination revealed normal results for the patient with progressive paraparesis.

CONCLUSION

Retethering of the spinal cord is a rare sequela after the sectioning of a tight filum terminale. The clinical presentation is typical for recurrent cord tethering, and the radiographic findings are subtle. Careful surgical exploration should be offered for spinal cord untethering. Awareness of this rare and hitherto undescribed sequela is necessary for appropriate long-term management of tethered spinal cord caused by a fatty filum terminale.

Spina bifida

Spina bifida (myelomeningocele) is the most common major birth defect among live-born infants. It is now recognized that half of those cases are preventable if folate is given periconceptionally. Epidemiology is discussed, together with an overview of approaches to orthopedic problems from birth to maturity.

Clinical features and MR imaging in children with repaired myelomeningocele

The aim of the study is to define the role of associated malformations in the clinical evolution of children affected by myelomeningocele. MRI investigation of the spinal cord was carried out on 25 patients between the age of 7.3 and 18.10 with MMC repaired and followed up for at least 7 years. The relation between associated malformations demonstrated by MRI and clinical trend was analysed. The results are the following: 1) presence of asymptomatic tethered cord in all cases; 2) high frequency (92%) of Chiari malformation; 3) presence of syringomyelia in 20% of patients, symptomatic in 1; 4) presence of ventricular enlargement in 72% of cases without increased intracranial pressure syndrome. For a better therapeutic approach prospective MRI studies are needed in order to follow up associated malformations.

Tethered-cord syndrome after repair of meningomyelocele

The occurrence of tethered-cord syndrome is one of the delayed consequences of the repair of meningo-myelocele. The existing neurological deficit worsens, or a new deficit is superimposed on the existing one. In addition, urological and orthopedic symptoms are also frequently encountered. Although radiological studies may be suggestive of tethering of the cord, not all children are symptomatic. Magnetic resonance imaging is the best radiologic study available. Ultrasonography, although economical and easy to perform, does not yield an optimal image. It appears that a careful periodic clinical evaluation is the best way to evaluate the patients for surgery.

Magnetic resonance imaging of dysraphic myelodysplasia. Findings in 56 children and adolescents with postrepair meningomyelocele

The spinal cord in 56 children and adolescents was examined by magnetic resonance imaging (MRI) many years after neonatal surgery on a meningomyelocele (average age 12 years). In a high percentage of cases, the diagnosis "tethered cord" was made. Associated anomalies were found with a frequency of 21%. Typical findings are presented and the impact of these results on therapy planning is discussed.