Disequilibrium in patients with posterior fossa arachnoid cysts.

Abstract

Arachnoid cysts (AC) are benign, congenital malformations of the leptomeninges. In our experience, dizziness and vertigo are common complaints in patients with such cysts. To quantify dizziness and imbalance in patients with arachnoid cysts in the posterior fossa using the Dizziness Handicap Inventory (DHI), Vertigo Symptom Scale Short-Form (VSS-SF) and Computerized Dynamic Posturography (CDP). We also wanted to investigate whether any dizziness and imbalance are reversible after surgical cyst decompression. The study includes four patients with AC in the posterior fossa (two in the cerebellopontine angle and two supracerebellar in the midline) and 15 control subjects undergoing ENT surgery for benign lesions of the larynx (n=10) or the parotid glands (n=5). All participants answered the DHI and VSS-SF and underwent CDP the day before, and at follow-up after surgery. The AC patients also graded their dizziness through the use of a Visual Analogue Scale (VAS). Preoperatively, cyst patients scored higher than controls on subjective symptoms (DHI, VSS-SF A and VSS-SF V) and had a lower score on postural sway (CDP). Symptom scores decreased after surgery; the cyst patients improved in the subjective tests (DHI, VAS and VSS-SF), and three of the patients improved their CDP scores. In the controls, symptom and CDP scores were unchanged after surgery. Patients with fossa posterior cyst had a significant preoperative impairment compared with the controls, and they exhibited post-operative improvement in their subjective dizziness.