Determinants for a Successful Sémont Maneuver: AnIn vitroStudy with a Semicircular Canal Model.
OBJECTIVE
To evaluate the effect of time between the movements/steps, angle of body movements as well as the angular velocity of the maneuvers in anin vitromodel of a semicircular canal (SCC) to improve the efficacy of the Sémont maneuver (SM) in benign paroxysmal positional vertigo.


METHODS
Sémont maneuvers were performed on anin vitroSCC model. Otoconia trajectories were captured by a video camera. The effects of time between the movements, angles of motion (0°, 10°, 20°, and 30° below the horizontal line), different angular velocities (90, 135, 180°/s), and otoconia size (36 and 50 μm) on the final position of the otoconia in the SCC were tested.


RESULTS
Without extension of the movements beyond the horizontal, thein vitroexperiments (with particles corresponding to 50 μm diameter) did not yield successful canalith repositioning. If the movements were extended by 20° beyond the horizontal position, SM were successful with resting times of at least 16 s. For larger extension angles, the required time decreased. However, for smaller particles (36 μm), the required time doubled. The angular maneuver velocity (tested between 90 and 180°/s) did not have a major impact on the final position of the otoconia.


CONCLUSIONS
The two primary determinants for success of the SM are the time between the movements and the extension of the movements beyond the horizontal. The time between the movements should be at least 45 s. Angles of 20° or more below horizontal line (so-called Sémont+) should increase the success rate of SM.
ARTORG Center for Biomedical Engineering Research, University of Bern , Bern , Switzerland.
Dominik
D
Obrist
ARTORG Center for Biomedical Engineering Research, University of Bern , Bern , Switzerland.
Andrea
A
Nienhaus
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Bern, Inselspital , Bern , Switzerland.
Ewa
E
Zamaro
Department of Neurology, Division of Cognitive and Restorative Neurology, University Hospital Bern, Inselspital , Bern , Switzerland.
Roger
R
Kalla
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Bern, Inselspital , Bern , Switzerland.
Georgios
G
Mantokoudis
Department of Neurology, German Center for Vertigo and Balance Disorders, University Hospital Munich , Munich , Germany.
Michael
M
Strupp
BPPV; Sémont liberatory maneuver; canalolithiasis; semicircular canal; vertigo
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