Canal Conversion and Reentry

Abstract

If the first CRP clears the posterior canal, there is an elevated risk of reentry or canal conversion if another Dix-Hallpike is performed immediately. These complications can be treated by additional maneuvers; if unfamiliar with these techniques, the risk can be reduced by waiting at least 15 minutes between repetitions of CRP.

Comparative Study on the Roles of the Number of Accelerations and Rotation Angle in the Treatment Maneuvers for Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo

“…Hence, we consider that canal conversion is an important index in our research. Although the incidence of canal conversion in BPPV patients is reportedly 7.8-21.7% [31,32,33], most of the patients with transitional BPPV can be easily treated by performing additional maneuvers [31]. Our results are consistent with these reports [31,33].…”

Benign positional vertigo, its diagnosis, treatment and mimics

“…Parnes et al (2003) point out that abolition of the nystagmus with repeat manoeuvres could be due to the fatigability of the response. Immediately repeating the Dix-Hallpike after treatment has been found to increase the risk (16%) of otoconia falling back into the posterior canal or entering the horizontal canal and requiring further manoeuvres ( Foster et al, 2012 ). For these reasons, it may be wise to avoid repeat manoeuvres in quick succession unless the nystagmus pattern is indicative of failed repositioning.…”

Treatment of benign paroxysmal positional vertigo. A clinical review

“…Since Foster et al. (2012) published their results, it has been widely accepted that performing the provocative testing just after the completion of the treatment will favour the particles to flow back into the posterior canal or to enter in another canal.…”

“…There is no consensus about the optimal time to test the effectivity of the manoeuvre. On one hand, to do it immediately may favour the reflux of the canalith and repeated positioning may also show a false successful treatment due to a fatigue response ( Foster et al., 2012 , Helminski et al., 2010 ). On the other hand, 30% of the patients with pc-BPPV may experience a spontaneous remission after a week ( Imai T, Ito M, Takeda N, Uno A, Marsunaga T, Sekine K, 2005 ), resulting in a successful result, wrongly attributed to the treatment manoeuvre.…”