Search

Objective Hemifacial spasm (HFS) associated with Chiari I malformation (CIM) is rare. This study aimed to analyze the frequency of HFS associated with CIM in our department and further to investigate the clinical characteristics, treatment strategies, and outcomes of these cases. Methods Twenty-eight of 831 patients with HFS who fulfilled the criteria for CIM were analyzed retrospectively. In this series, microvascular decompression (MVD) was performed in 23 patients (82.1%). The remaining 5 patients (17.9%) with obvious symptoms attributable to CIM were treated only with foramen magnum decompression. The mean follow-up period was 41 ± 21.7 months. Results The frequency of HFS associated with CIM was 3.4%. There were 19 women (67.9%) and 9 men (32.1%) with a mean age of 36.4 ± 7.5 years. The most common symptoms were headache, paraesthesias, and muscular weakness with the exception of typical HFS. Seventeen patients (73.9%) experienced immediate postoperative spasm relief, and 21 patients (91.3%) were spasm relief at discharge after MVD. However, 3 patients (14.3%) experienced delayed recurrence of HFS after successful MVD in the follow-up. After foramen magnum decompression, 3 of 5 patients experienced complete relief of the spasm, and 4 patients showed improvement in the CIM-related symptoms. Conclusions The results suggest that MVD can still be an effective treatment for HFS when it coexists with CIM. Furthermore, posterior fossa crowdedness may be a common risk factor for the 2 diseases, and foramen magnum decompression should be considered as the primary procedure in patients with HFS and symptomatic CIM.

Objective To prospectively evaluate the morphological and structural changes in the trigeminal nerve in patients with trigeminal neuralgia (TN) compared with healthy controls. Methods We conducted a prospective case-control study of 60 consecutive patients diagnosed with TN and 30 sex-and age-matched healthy controls. All subjects underwent high-resolution 3-dimensional magnetic resonance imaging (MRI). The volume and length of the cisternal segment of the trigeminal nerve and the angle between the trigeminal nerve and the anterior surface of the pons (trigeminal pontine angle) were measured and compared. Results The mean volume of the affected trigeminal nerve was significantly reduced compared with that of the nonaffected side (65.8 ± 21.1 mm 3 vs. 77.9 ± 19.3 mm 3 ; P = 0.001) and controls (65.8 ± 21.1 mm 3 vs. 74.7 ± 16.5 mm 3 ; P = 0.003). The mean trigeminal pontine angle was 42.4 ± 8.7° on the affected side, 47.6 ± 9.2° on the nonaffected side, and 46.0 ± 7.2° in the controls. The trigeminal pontine angle on the affected side was significantly smaller than that on the nonaffected side ( P = 0.005) and in controls ( P = 0.01). There the was no statistically significant difference in the mean length of the cisternal segment of trigeminal nerve between the affected and nonaffected sides ( P = 0.46). Conclusions TN is associated with atrophy and a small trigeminal pontine angle in the affected nerve. Nerve atrophy may be a late consequence of chronic physical stress and is likely involved in the pathogenesis of TN. A small trigeminal pontine angle may increase the risk of neurovascular conflict, and thus more likely to result in the genesis of TN.