Anterior Canal Lithiasis: Diagnosis and Treatment

Objective. To describe the clinical and oculographic features in patients with anterior semicircular canal benign paroxysmal positional vertigo and to determine the efficacy of a canalith repositioning procedure for its management. Study Design. Case series with chart review of patients presenting positional vertigo and positional downbeating nystagmus during a 2-year period. Setting. Outpatients' tertiary referral center for balance disorders. Subjects and Methods. Eighteen patients suffering from positional vertigo and presenting positional downbeating nystagmus were treated with a maneuver based on a modification of the procedure proposed by Crevits. Mean outcome measure: disappearance of positional downbeating nystagmus. Results. Positional downbeating nystagmus was elicited unilaterally with the Dix-Hallpike maneuver in 6 cases. In 4 patients, it was triggered by both left and right Dix-Hallpike tests. In 8 patients, the positional nystagmus was elicited by a straight head-hanging maneuver. The positional nystagmus was purely downbeating in 12 patients. In the remaining, a torsional component was detected. After the treatment, only 1 patient showed positional nystagmus at 30 days. Conclusion. In anterior canal benign paroxysmal positional vertigo, the presence of a positional downbeating nystagmus in response to positional tests is key for diagnosis. In a significant number of patients, the affected side may not be detected because of the inconstant presence of a torsional component. Treatment with a simplified maneuver based on Crevits's technique can be considered an effective method for the treatment of anterior canal lithiasis, especially when the affected side cannot be detected clearly.