The Canalith Repositioning Procedure (CRP) is designed to treat benign paroxysmal positional vertigo (BPPV) through induced out-migration of free-moving pathological densities in the endolymph of a semicircular canal, using timed head maneuvers and applied vibration. This article describes the procedure and its rationale, and reports the results in 30 patients who exhibited the classic nystagmus of BPPV with Hallpike maneuvers. CRP obtained timely resolution of the nystagmus and positional vertigo in 100%. Of these, 10% continued to have atypical symptoms, suggesting concomitant pathology; 30% experienced one or more recurrences, but responded well to retreatment with CRP. These results also support an alternative theory that the densities that impart gravity-sensitivity to a semicircular canal in BPPV are free in the canal, rather than attached to the cupula. CRP offers significant advantages over invasive and other noninvasive treatment modalities in current use.

Three distinct pathological conditions, related to different means by which dense intralabyrinthine particles interfere with the function of a semicircular canal and cause nystagmus and vertigo, are amenable to treatment with repositioning maneuvers. Known as benign paroxysmal positional vertigo and variants, these conditions are better designated collectively by the term “vestibular lithiasis.” Each form requires a different treatment strategy of head maneuvers and application of other modalities to restore normal semicircular function and thereby eliminate the positional nystagmus and vertigo. Real‐time observation of the nystagmus induced by the particles during the maneuvers can greatly facilitate the repositioning process.

My clinical and laboratory observations support the theoretical concept that the mechanism of typical nystagmus, and most forms of atypical transient nystagmus, is hydrodynamic drag by gravitating free densities--most commonly displaced otoconia--in the endolymph of a semicircular canal; and that these "canaliths" have a significant mechanical advantage, by virture of the canal/ampulla cross-sectional differential, over densities acting directly on the cupula. Positional vertigo related to apparent canalithiasis (benign paroxysmal positional vertigo) is a common cause of incapacitation. The profile of the concomitant nystagmus localizes the semicircular canal involved. The canalith repositioning procedure, appropriately administered and targeted according to the observed nystagmus, provides a highly effective means for control of symptoms and a valuable resource for diagnostic evaluation of the more complex case. Surgery is rarely indicated.

Twenty-nine patients who demonstrated the classic nystagmus of benign paroxysmal positional vertigo in the provocative, ear-down position had a high incidence of concurrent symptoms. These included vertigo provoked by arising, bending over, head rotation, linear acceleration, and vertical oscillation. Some have not been reported previously in relation to this syndrome. Elimination of both concurrent and classic symptoms via singular neurectomy in nine patients indicates a common pathophysiologic mechanism, probably involving cupulolithiasis in the posterior semicircular canal. These concurrent symptoms should be considered part of the syndrome.

This advancement should be considered for tertiary management of complicated labyrinthine lithiasis.