RESUMEN
OBJECTIVE: Postural restrictions after canalith repositioning maneuvers (CRM) for benign paroxysmal positional vertigo of the posterior semicircular canal (p-BPPV) have no proven value and therefore most physicians regard them as unnecessary. The aim of this study was to assess the short-term efficacy of head and body movement limitations after a single Epley maneuver. A review of the literature was performed to assess the current level of evidence for the efficacy of postural restrictions. MATERIALS AND METHODS: Sixty-four patients, median age 59 years (range 37-82 years), with p-BPPV, were allocated either to instructions for movement restrictions or free movements for 48 h after a single Epley maneuver. The minimization method was used for allocation to treatment. This procedure 'minimizes' the differences in the distribution of pre-specified prognostic factors (e.g. sex and age) between the two groups of treatment. Minimization was preferred over randomization which is not as effective in balancing baseline characteristics when the number of participants is small. Outcome was assessed by physician and patient reported measures (Dix-Hallpike test, subjective vertigo intensity in a 10-point scale, patient's assessment of improvement) within 1 week after treatment by an independent investigator. The level of statistical significance was 0.05. RESULTS: More patients with movement restrictions reported a subjective improvement after treatment (p=0.007). Ninety percent of patients with movement restrictions and 74.2% of patients with free movements had a negative follow up Dix-Hallpike test but the difference was not significant (p=0.108). The mean pre-treatment vertigo intensity was reduced from 6.07 and 5.97 to 1.18 and 2.86, respectively but the difference was not significant (p=0.122). CONCLUSIONS: Postural restrictions do not increase the efficacy of the canal-repositioning maneuver despite the fact that patients report a subjective improvement after post-procedural instructions. In the review of the literature, all studies except one conclude that postural restrictions are unnecessary. However, a number of methodological issues such as inadequate sample size are not addressed and more conclusive evidence is required. Based on current evidence, the use of postural restrictions after the canal-repositioning maneuver is unjustified.