title: [Clinical research of the otolith abnormal migration during canalith repositioning procedures for posterior semicircular canal benign paroxysmal positional vertigo].
abstract: OBJECTIVE
  To investigate the risk factor,type and characteristic nystagmus of the otolith abnormal migration during diagnosis and treatment for posterior semicircular canal benign paroxysmal positional vertigo (PSC-BPPV). The therapy and prevention is also discussed.
  
  
  METHODS
  Four hundred and seventy-nine patients with PSC-BPPV were treated by Epley's canalith repositioning procedures(CRP) from March 2009 to March 2012. We observed otolith abnormal migration complicating during diagnosis and treatment. According the type of otolith abnormal migration, the additional repositioning maneuver was performed.
  
  
  RESULTS
  The rate of complication was 8. 1%(39/479), with canal conversion in 5.4%(26/479) and primarily canal reentry in 2.7%(13/479). The rate of incidence of conversion to horizontal canal conversion and anterior canal were 4. 8%(23/479)and 0. 6%(3/479) respectively. All the patient was cured in follow up. The risk factors were unappropriated head movement during or after CRP, including another Dix-Hallpike were performed immediately.
  
  
  CONCLUSIONS
  To prevent the complications,the pathognostic positioning sequence and angle of head rotation are commenced during CRP. Appropriate short time postural restrictions post-treatment is necessary. Careful observation of nystagrnus variation is crucial to determine the otolith abnormal migration.
authors.forename: Yongkang
authors.initials: Y
authors.lastname: Ou
authors.forename: Yiging
authors.initials: Y
authors.lastname: Zheng
authors.forename: Honglei
authors.initials: H
authors.lastname: Zhu
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
authors.forename: Junwei
authors.initials: J
authors.lastname: Zhong
authors.forename: Xiaowu
authors.initials: X
authors.lastname: Tang
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: Huang
authors.forename: Yaodong
authors.initials: Y
authors.lastname: Xu
mesh_terms: D065635:Benign Paroxysmal Positional Vertigo / Q000628:therapy*; D006257:Head; D006801:Humans; D015994:Incidence; D009759:Nystagmus, Pathologic / Q000209:etiology*; D010037:Otolithic Membrane; D056888:Patient Positioning / Q000009:adverse effects*; D012665:Semicircular Canals; D014717:Vertigo