Potential of proton magnetic resonance spectroscopy in the evaluation of patients with tethered cord syndrome following surgery.

OBJECT: Spinal cord dysfunction is associated with an altered neuronal metabolism. The objective of this study is two-fold: 1) to compare pre- and postoperative levels of cerebrospinal fluid (CSF) metabolites in patients with spinal dysraphism and in control patients by performing proton magnetic resonance spectroscopy; and 2) to evaluate the use of magnetic resonance (MR) spectroscopy in the assessment of surgical outcomes in patients with spinal dysraphism.

METHODS

The study group population was composed of patients with meningomyeloceles, lipomeningomyeloceles with tethered cord syndrome, and tethered fatty fila. All patients underwent preoperative clinical and neuroimaging (ultrasonography or MR imaging) examinations and MR spectroscopy analysis of metabolites in their CSF. Excision of the neural placode and detethering of a low-lying cord were performed with or without laminectomy. Two months postoperatively, the investigations were repeated. A comparison of pre- and postoperative CSF metabolites was performed using the Wilcoxon signed-rank test and nonparametric tests. Probability values less than 0.05 were considered significant. High levels of lactate (Lac), alanine (Ala), acetate, glycerophosphorylcholine, and choline were observed in the CSF of patients with spinal dysraphism before surgery; after surgery these levels normalized to those observed in control patients. Patients in whom cord retethering occurred could be identified by increased concentrations of Ala and Lac.

CONCLUSIONS

The results highlight the potential of MR spectroscopy as a promising tool in the assessment of surgical outcomes in patients with spinal dysraphism.