J Neurol DOI 10.1007/s00415-014-7290-2
ORIGINAL COMMUNICATION
Canal conversion after repositioning procedures: comparison of Semont and Epley maneuver Evangelos Anagnostou • Eleftherios Stamboulis Evangelia Kararizou
•
Received: 9 January 2014 / Revised: 16 February 2014 / Accepted: 17 February 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract Although the efficacy of Semont (SM) and Epley maneuvers (EM) for treatment of posterior canal benign paroxysmal positional vertigo (BPPV) is well established, data comparing SM and EM regarding maneuver-induced canal switch are lacking. We prospectively investigated 102 posterior canal BPPV patients after application of the Semont or the Epley maneuver and looked for the appearance of ipsilateral horizontal canal BPPV symptoms. Although treatment success was similar for SM and EM (67 and 76 %, respectively), there was a significant difference in posterior-to-horizontal canal switch rates. In particular, 4 of 51 patients (7.8 %) of the EM group converted to the geotropic type of horizontal canal BPPV, whereas none of the 51 SM patients exhibited a canal switch. All four patients were cleared with a single barbecue maneuver. Our data suggest a small but significant difference in canal switch rate between EM and SM, which could be partly explained by the higher number of maneuver steps during which the head is in the dependent position throughout the EM. Keywords Neuro-otology Benign paroxysmal positional vertigo Semont Epley
characterized by brief attacks of rotational vertigo triggered by changes in position of the head relative to gravity. Canalolithiasis, a condition where otoconia that have been dislodged from the utricle are floating freely in the endolymph, is generally accepted as the cause of BPPV. Clinical diagnosis is made by the Dix-Hallpike or the side-lying maneuver, which both have a high specificity and sensitivity. Standard of treatment are the repositioning maneuvers of Epley [2] and Semont [3], both having a high success rate (78 % on average) even after a single treatment session [4]. The former is used in many centers worldwide, while the latter is practiced mainly in Europe. Over the last several years, experts increasingly encourage non-specialist primary care physicians as well as patients at home to apply the repositioning maneuvers in order to benefit from their high efficacy and avoid costly admissions and diagnostic procedures. Side effects are considered to be uncommon, although accidental ‘‘canal switch’’ is beginning to be recognized as a complication of canalith repositioning maneuvers. ‘‘Canal switch’’ occurs when a posterior canal BPPV converts to ipsilateral horizontal (or anterior) canal BPPV after treatment exercises. The aim of this study was to compare EM with SM regarding their potential for inducing canal conversion.
Introduction Methods Benign paroxysmal positional vertigo (BPPV) of the posterior semicircular canal is the most common cause of episodic vertigo with a lifetime prevalence of 2.4 % [1]. It is E. Anagnostou (&) E. Stamboulis E. Kararizou Department of Neurology, Eginition Hospital, University of Athens, Vas. Sophias Avenue 74, 11528 Athens, Greece e-mail:
[email protected]
A prospective study was undertaken in 124 consecutive patients who were referred between October 2007 and October 2013 to our department for evaluation and management of positional vertigo. Only subjects with a positive Dix-Hallpike or side-lying test indicative of posterior canal BPPV on one side were included. Exclusion criteria were bilateral posterior canal or non-posterior canal BPPV, positional vertigo with
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signs of CNS involvement, and vertigo not accompanied by nystagmus. All patients gave written informed consent for participation in the study, which was conducted in accordance with the Declaration of Helsinki and approved by our institution’s Ethics Committee. After a Dix-Hallpike or a side-lying test (applied for both sides to exclude bilateral BPPV) identifying the affected side, patients received either a modified Epley canalith repositioning (EM) or a Semont liberatory maneuver (SM). The maneuver was performed only once independent of the occurrence of a liberatory nystagmus. To minimize the possibility of selection bias, we assigned every second patient to the SM, while the others received the EM. Factors such as age, gender, obesity or neck stiffness were not considered. Response to treatment was assessed on the same day, 2–5 h after the repositioning maneuver. Between the two sessions the patients remained in the sitting position in the emergency department’s waiting room without any specific instructions. A negative Dix-Hallpike test, yielding no nystagmus at all, was considered a treatment success, independent from patients’ report of vertigo. At this point, occurrence of horizontal (from canthus to canthus) geotropic nystagmus without visible vertical or torsional components was taken as evidence of ipsilateral horizontal canal affection due to canal conversion. Both the therapeutic and the success-assessment maneuver were carried out by the same physician in a non-blinded way. Statistical analysis The effect of applied maneuver on symptom resolution and canal conversion was investigated by cross-tabulation matrices and Chi-square statistics. Parameters such as gender, affected side, and age were also assessed by means of Chi-square and t test statistics where appropriate. Significance was set at 0.05.
Table 1 Demographic and BPPV parameters, maneuver success, and canal conversion rate Semont maneuver (SM)
Epley maneuver (EM)
Difference
Number of patients
51
51
NS NS
Age (mean ± SD)
53.2 ± 17.4
57.8 ± 14.5
Sex (female/male)
26/25
25/26
NS
Affected side (right/left)
24/27
27/24
NS
Success (yes/no) [%/%]
34/17 [67/33]
39/12 [76/24]
NS
Conversion (yes/no) [%/%]
0/51 [0/100]
4/51 [7.8/92.2]
*
NS not significant * Significant at 0.05
differ significantly between the two groups (t = -1.449, p [ 0.05). Sex distribution was also similar in the SM and the EM populations (v2 = 0.039, p [ 0.05). Frequency of right and left posterior canal BPPV was also similar in the EM group as compared to the SM group (SM: 24/27 and EM: 27/24, v2 = 0.353, p [ 0.05). These data are summarized in Table 1. Both SM and EM were successful in 67 and 76 % of cases, respectively. This small difference in favor of the EM was not significant (v2 = 1.205, p [ 0.05). A difference was found in the posterior canal to horizontal canal switch rate. In particular, 4 of 51 EM cases converted, whereas no conversions occurred in the SM group. (v2 = 4.163, p \ 0.05) (Table 1). Patient sex (v2 = 1.041, p [ 0.05), age (t = -0.444, p [ 0.05), and affected canal side (v2 = 1.041, p [ 0.05) did not exhibit a statistical association with conversion rate. All four canal-switch cases showed geotropic nystagmus and were treated successfully with the barbecue (Lempert) maneuver. No posterior to anterior canal conversions were observed.
Results Discussion Inclusion criteria were met by 102 subjects. Although care was taken that consecutive patients did not receive the same maneuver, this rule was violated two times due to nearly simultaneous arrival of two patients in separate emergency rooms, who were examined and treated by two examiners incidentally by the same maneuver. The next two patients were then treated with the other maneuver, proceeding thereafter with the initial randomization method (see ‘‘Methods’’). Accordingly, 51 subjects received the SM and 51 the EM. Mean age was 53.2 years (range 19–89, 26 females) in the SM group and 57.8 years (range 29–80, 25 females) in the EM group. Age did not
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We found that both SM and EM were effective in ameliorating the symptoms of BPPV after a single application of the repositioning procedure. SM was successful in 67 % and EM in 76 % of the cases, a difference that was not significant. These rates conform well with previous studies [5] that report cure rates ranging from 58 to 92 % for SM and from 67 to 95 % for EM. These variations might arise from differences in maneuver performance per se or differences in success criteria. Immediate repetition of the maneuver if unsuccessful and expertise of the physician (vertigo referral center versus primary care department) fall
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in the first category, while timing of effectiveness evaluation (same day or later) and consideration of subjective dizziness fall in the second category. Head-to-head studies comparing EM and SM are sparse, and no clear-cut outcome differences have been demonstrated so far [4, 6]. The main finding in our study was the difference in canal switch rates between SM and EM. The latter was associated with a 7.8 % posterior-to-horizontal conversion rate (4 out of 51 patients), whereas no conversions were observed with the Semont procedure. The barbeque maneuver was applied successfully in all four cases. Literature on canal switch frequency is sparse. The only prospective study using canal conversion rate as a primary outcome measure reported that 9.1 % of cases experienced posterior-to-horizontal canal switch after a single EM [7]. All horizontal canal converters exhibited nystagmus of the geotropic type. Interestingly, 6.8 % had a posterior-toanterior canal switch, whereas one patient exhibited both horizontal and anterior canal symptoms and was counted to both categories. Conversion frequency was also explicitly analyzed in a retrospective study which demonstrated a 6.2 % rate of posterior-to-horizontal switch using the EM [8]. Furthermore, a well-documented study investigating EM effectiveness as a primary outcome reported a 6.9 % posterior-to-horizontal conversion rate [9]. The only study considering conversion rate with the SM reported a frequency of 4.6 % [10]. It was not clear, however, whether the study was retrospective or prospective. Finally, it is worth mentioning a retrospective analysis of horizontal canal BPPV cases which reported that 51 of 83 (61 %) patients had initially presented with posterior canal and converted through therapeutic maneuvers to horizontal canal BPPV [11]. To the best of our knowledge, head-tohead studies comparing canal conversion rates between EM and SM are not available. Patients cleared with a repositioning maneuver are likely to have a large mass of otoconia located near the opening to the semicircular canals at the end of the maneuver. The opening to the horizontal canal is immediately adjacent to the opening of the posterior and anterior canals (common crus). At this point, the patient is at risk for debris reentry. This risk increases if the head is placed in a head hanging position. One might assume that the EM, consisting of more steps than the SM, maintains the patient in the dependent position for a longer period of time, thus increasing the odds for particle reentry. Theoretically, canal switch might also have been caused during the Dix-Hallpike maneuver that we performed in order to test treatment success, rather than during the repositioning maneuvers. However, this would not explain the canal conversion differences between EM and SM, since we applied subsequent Dix-Hallpike testing for both maneuvers.
As mentioned above, a successful maneuver was defined as ‘‘no nystagmus at all’’ in our design, which implies that posterior-to-lateral canal converters among the EM-treated patients are a subgroup of the unsuccessful cases. On the other hand, all unsuccessful cases in the SM group represent persistence of posterior canal BPPV. Hence, a practical consequence might be that therapists preferentially using the EM should be aware that uncleared cases might actually harbor a canal switch, and this complication should be explicitly looked for since it implies the need for a different liberation procedure. The fact that the reevaluation maneuver was carried out within 2–5 h post-treatment could theoretically flaw our results because of debris remaining in dispersion or because part of the debris could reenter the canal. As there is no reliable literature supporting a strict minimal interval between canalith repositioning and evaluation procedures, we chose this rather short time lapse in the present study for feasibility reasons. Nonetheless, a thereby introduced bias would appear both in the EM and SM group, and since our analysis is focused on differences between these two procedures, it would virtually cancel out. Furthermore, it should be mentioned that the present data are based on a limited sample of 102 patients. Hence, chance effects or idiosyncratic anatomical predispositions of patients’ labyrinths cannot be ruled out in strict epidemiological terms. In conclusion, our results indicate a small but significant difference between EM and SM regarding posterior-tohorizontal canal conversion frequency. This might gain importance when consulting patients for self-administration of therapeutic maneuvers, given the fact that the barbecue maneuver that could correct a canal switch, although simple and successful, has not been yet evaluated for application at home. Since the sample of the present study is relatively small, larger prospective and retrospective comparative observations are needed in order to draw final conclusions. Conflicts of interest On behalf of all authors, the corresponding author states that there is no conflict of interest. Ethical standard All patients gave written informed consent for participation in the study, which was conducted in accordance with the Declaration of Helsinki and approved by our institution’s Ethics Committee.
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