CSF flow study in Chiari I malformation.

Abstract

The aim of this prospective study was to define the role of cardiac gated phase-contrast ciné magnetic resonance imaging in deciding the therapeutic strategy in patients with Chiari I malformation. Twenty-one patients operated on between February 2000 and July 2002 were enrolled in the study. All patients underwent a detailed preoperative neurological examination. MRI of the craniovertebral junction and the whole spine was done, followed by cardiac gated phase contrast ciné magnetic resonance imaging. Signs and symptoms of syringomyelia were noted in 15 patients and cerebellar signs in 11 patients. Three of them had trigeminal nerve involvement, and 4 had ninth and tenth cranial nerve involvement. The sixth and accessory nerves were involved in 1 patient each. Preoperative CSF flow studies revealed obstructive flow both anteriorly and posteriorly in 6 patients and only posterior block in 15 patients. One patient investigated for failed foramen magnum decompression revealed obstruction to CSF flow ventrally. Foramen magnum decompression with duroplasty was done in all these cases. The patient who had a persistent ventral flow block underwent odontoidectomy. Patients were followed up for a maximum of 36 months, with a mean of 18 months. MRI CSF flow studies revealed established flow dorsally in all cases. Seventeen patients showed clinical improvement and 2 of them did not show any neurological changes. Two patients deteriorated following an initial period with a shunt. MRI CSF flow study is an effective tool for deciding the type of surgery to be performed and also for monitoring patients postoperatively.