Determinants for a Successful Sémont Maneuver: An In vitro Study with a Semicircular Canal Model

Abstract

ObjectiveTo evaluate the effect of time between the movements/steps, angle of body movements as well as the angular velocity of the maneuvers in an in vitro model of a semicircular canal (SCC) to improve the efficacy of the Sémont maneuver (SM) in benign paroxysmal positional vertigo.Materials and MethodsSémont maneuvers were performed on an in vitro SCC 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.ResultsWithout extension of the movements beyond the horizontal, the in vitro experiments (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.InterpretationThe 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.

Treatment of horizontal canal BPPV—a randomized sham‐controlled trial comparing two therapeutic maneuvers of different speeds

“…The effect of acceleration and deceleration during barbecue maneuvers for horizontal canal benign paroxysmal positional vertigo (HC-BPPV) has been debated. [1][2][3][4] is the most common cause of vertigo, and HC-BPPV is the second most common subtype, 5,6 with a prevalence ranging from 5% to 30% in patients with BPPV. [7][8][9] The commonly accepted cause of BPPV is ectopic otoconia located within the lumen of the semicircular canals (canalolithiasis) or attached to the cupula (cupulolithiasis), 10,11 generating attacks of positional nystagmus and vertigo after certain head movements.…”

Management of Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo

“…The posterior semicircular canal variant of BPPV (PC-BPPV) is a well-recognized condition, since it was described in 1952. It is characterized by a torsional vertical nystagmus provoked by the Dix Hallpike maneuver (21) or diagnostic Sémont maneuver (22,23). In contrast, the first reports of the lateral semicircular canal variant of BPPV (LC-BPPV) were published in 1985 (24,25).…”

Congruous Torsional Down Beating Nystagmus in the Third Position of the Semont's Maneuver in Patients Treated for Canalithiasis of Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo: Its Significance and Prognostic Value

“…The first movement of the maneuver brings the patient from the sitting position to that of the pathological side (Figure 1, 1st). The latter shift should be performed with a high angular velocity and by reaching a position such that the body is displaced 110 • with respect to the sitting position (the head being positioned 20 • under the horizontal plane); actually, an only 90 • displacement could be insufficient to move the particles in the declivous part of the PSC (12). In the case of a canalolithiasis, positioning the patient onto the pathological side causes the migration of the otoconial debris, by means of gravity, from the ampullary arm toward what it becomes the most declivous part of the PSC in the new position.…”

“…The resulting nystagmus beats, therefore, upward and in a counterclockwise and clockwise direction (from the examiner's point of view from now on), due to the involvement of the right and left PSC, respectively. Once such an ocular movement, which we defined LoNy, is exhausted and waited about 45 s since the position is reached (12), the operator brings the patient onto the non-pathological side (Figure 1, 2nd) taking care to maintain the head still turned 45 • toward it. The latter shift should have a 220 • amplitude and should be executed with a high velocity.…”

“…that is lower than the horizontal is more effective in moving the cloth toward the utricle (12). With such a second movement, in the case of a canalolithiasis, the maneuver aims to move the otoconial debris still in the ampullofugal direction, toward the utricle.…”