360 DEGREE ROTATION OF THE POSTERIOR SEMICIRCULAR CANAL FOR TREATMENTOF BENIGN POSITIONAL VERTIGO - A PLACEBO-CONTROLLED TRIAL

The canalithiasis hypothesis proposes that benign positional vertigo ( BPV) is caused by dislodged otoconia that settle in the posterior semi circular canal (PSC). When head position is changed these particles mo ve within the canal and induce abnormal endolymph flow. To clear the P SC from debris we developed a procedure that consists of a full circle of backward head rotation in the exact plane of the canal. Patients w ere seated in a three-dimensional motion device that rotated in steps of 110 degrees every 30 seconds. The first part of the study was condu cted as an open trial; the second part followed a single-blinded, plac ebo-controlled design: Forward rotation (placebo) was applied first an d backward rotation was applied 1 week later if BPV persisted. All pat ients were assessed with a symptom diary and, in the controlled trial, also with the Dix-Hallpike maneuver. In the open study 10 of 15 patie nts became asymptomatic after one treatment session. in the controlled trial all 15 patients remained symptomatic after forward rotation whi le 10 of 14 undergoing backward rotation were relieved from positional vertigo immediately (p = 0.004). The presence of secondary nystagmus during the procedure indicated a favorable outcome. Our findings provi de evidence for the efficacy of canal-clearing procedures that validat e the canalithiasis hypothesis of BPV.