Abstract: Objective To investigate clinical features of transformable-direction eye shock and to evaluate the efficacy of manual reduction in its treatment in patients with lateral semicircular canal benign paroxysmal positional vertigo(LSC-BPPV). Methods A retrospective analysis was performed on thirty-five transformable-direction eye shock patients with LSC-BPPV(the transformable group)and thirty-eight invariant-direction eye shock patients with LSC-BPPV(the invariant group)from Jan. 2016 to Jul. 2017 in our hospital. The results were compared between these two groups. All patients were followed up for 6 months. Statistical analysis was performed using SPSS 19.0 software. Results The transformable group included 7 cases of spontaneous eye shock and 28 cases of intentional eye shock. Apogeotropic eye shock was changed to geotropic eye shock in 31 patients, and geotropic eye shock was changed to apogeotropic eye shock in 2 patients. Other 2 patients showed transformable-direction eye shock, which was repeated many times. The eye shock duration was more than 1 min in 6 patients,but it was less than 1 min in 29 patients. All patients were administered manual reduction treatment according to the eye shock direction and duration with the Barbecue maneuver, Gufoni maneuver, and forced prolonged position maneuver. The efficacy after the first manual reduction treatment was 62.86%(22/35)in the transformable group and 86.84%(33/38)in the invariant group, and the difference in the treatment efficacy was significant between these two groups(χ2=5.642, P=0.018). Total efficacy was 91.43%(32/35)in the transformable group and 97.37%(37/38)in the invariant group after manual reduction treatment for more than once, and no significant differences in total efficacy were observed between these two groups(χ2=1.241, P=0.265). The number of circulation of first success was 2.81±1.21 in the transformable group and 1.56±0.69 in the invariant group after manual reduction management, and a significant difference was found between these two groups(t=4.053, P=0.000). The recurrence rate was 17.14% in the transformable group and 23.68% in the invariant group at the 6-month follow-up visit, but no significant differences were observed between these two groups(χ2=0.478, P=0.490). Conclusion The key step for successful treatment is to determine which otolith and canal types are accurately affected. The efficacy after the first manual reduction treatment was lower in the transformable group than in the invariant group. More circulation of first success was needed in the manual reduction management. The total efficacy and recurrence rate did not show significant differences between these two groups. Therefore, manual reduction is an effective treatment for transformable-direction eye shock patients with LSC-BPPV.

Key words: Lateral semicircular canal, Manual reduction, Vertigo, Eye shock, Otolith