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Prognostic Value of Abnormal Muscle Response During Microvascular Decompression for Hemifacial Spasm: A Meta-Analysis
Literature Review
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Prognostic Value of Abnormal Muscle Response During Microvascular Decompression for Hemifacial Spasm: A Meta-Analysis Jie Zhang1, Zong-Hao Li2, Jin-Feng Wang1, Yong-Han Chen2, Ning Wang1, Yi Wang2
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- OBJECTIVE:
To perform a comprehensive meta-analysis to systematically assess the value of abnormal muscle response (AMR) in predicting the surgical outcome of patients with hemifacial spasm.
Key words Abnormal muscle response - Hemifacial spasm - Lateral spread response - Microvascular decompression -
- METHODS:
Abbreviations and Acronyms AMR: Abnormal muscle response AUC: Area under the curve CI: Confidence interval DOR: Diagnostic odds ratio HFS: Hemifacial spasm LRN: Negative likelihood ratio LRP: Positive likelihood ratio LSR: Lateral spread response MVD: Microvascular decompression Q2 RR: Relative risk From the Departments of 1Neuroelectrophysiology and Neurosurgery, Cangzhou Central Hospital, Yunhe District, Cangzhou, Hebei, People’s Republic of China
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To whom correspondence should be addressed: Zong-Hao Li, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2020). https://doi.org/10.1016/j.wneu.2020.01.166 Journal homepage: www.journals.elsevier.com/worldneurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2020 Elsevier Inc. All rights reserved.
The electronic database PubMed, Embase, Web of Science, and ScienceDirect were searched, and relevant articles were identified up to September 30, 2019. These data were extracted for pooled analysis, heterogeneity testing, sensitivity analysis, publication bias analysis, and Fagan plot analysis.
- RESULTS:
The disappearance of AMR during microvascular decompression was associated with a favorable short-term surgical outcome (pooled relative risk [RR], 1.42; 95% confidence interval [CI], 1.24e1.62; pooled RR adjusted for publication bias, 1.30; 95% CI, 1.08e1.57). The corresponding pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.91 (95% CI, 0.88e0.94), 0.34 (95% CI, 0.27e0.42), 1.4 (95% CI, 1.2e1.6), 0.26 (95% CI, 0.17e0.38), and 5 (95% CI, 3e9), respectively. The disappearance of AMR was almost ineffective in predicting the long-term surgical outcome (pooled RR, 1.09; 95% CI, 1.02e1.17; pooled RR adjusted for publication bias, 1.001; 95% CI, 0.92e1.09). The corresponding pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.90 (95% CI, 0.85e0.93), 0.28 (95% CI, 0.20e0.37), 1.2 (95% CI, 1.1e1.4), 0.38 (95% CI, 0.22e0.63), and 3 (95% CI, 2e6), respectively.
- CONCLUSIONS:
The disappearance of AMR during microvascular decompression demonstrates limited prognostic value for a favorable short-term outcome, and does not appear effective in predicting the long-term outcome of patients with hemifacial spasm.
INTRODUCTION Hemifacial spasm (HFS) is a neuromuscular disorder characterized by involuntary contraction of facial muscles, can result in increasing embarrassment and social withdrawal for the individual, and even functional blindness due to involuntary eye closure in severe cases.1 Although the exact mechanism of HFS remains unclear, the primary cause of this disorder is considered to be vascular compression of the facial nerve root entry zone.2 Microvascular decompression (MVD) is a highly effective and safe treatment modality and has been established as the goldstandard treatment for HFS based on its etiology. However, the results of MVD are not always satisfactory.3,4 Abnormal
muscle response (AMR), also known as the lateral spread response (LSR), is an abnormal electrophysiological characteristic and can be elicited by stimulating 1 branch of the facial nerve and simultaneously recording from muscles innervated by other branches of the facial nerve in patients with HFS. It usually disappears after adequate decompression of the facial nerve from neurovascular contact and may thus facilitate the confirmation of adequate decompression. Accordingly, AMR monitoring is widely performed to guide the surgeon during MVD and to predict the surgical outcome of patients with HFS. However, some investigators
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questioned the reliability of AMR because the disappearance of AMR does not always lead to the relief of HFS, although the persistence of AMR does Q 3 not definitely mean the operation failed. Overall, the prognostic value of the disappearance of AMR remains vague and controversial.5,6 Therefore we conducted a meta-analysis to evaluate the value of the disappearance of AMR during MVD in predicting the outcomes of patients with HFS. METHODS This study was performed according to the Preferred Reporting Items for Systematic
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Literature Search Strategy A systematic literature search was performed in PubMed, Embase, Web of Science, and ScienceDirect using Medical Subject Headings and general search terms from their date of inception until September 30, 2019 to identify relevant studies. The search strategy used different combinations of the following terms: “hemifacial spasm,” “abnormal muscle response,” “lateral spread response,” “electrophysiological,” and “microvascular decompression.” The records retrieved from electronic databases were first screened by the titles and abstracts, and then full-text articles of relevant studies were retrieved for further review. Manual searches were conducted in the reference lists of relevant articles to obtain additional articles. A literature search was conducted by 2 reviewers independently, and they then reviewed and selected articles for further analysis. Disagreement was resolved by discussion with other reviewers.
Figure 1. Flow chart of selection process to enroll eligible studies.
Reviews and Meta-Analyses (PRISMA) guidelines.7 All results and analysis were based on previously published studies,
and thus there was no need to seek further ethical approval and patient consent.
Table 1. Characteristics of Included Studies Study
Country
Yamashita et al., 20059
Japan
Retrospective cohort
Kong et al., 200710
South Korea
Retrospective cohort
Joo et al., 200811
China
Retrospective cohort
12
Li et al., 2012
Japan
Retrospective cohort
Ying et al., 201113
China
Retrospective cohort
United States
Retrospective cohort
Tobishima et al., 201414 6
Germany
Retrospective cohort
South Korea
Retrospective cohort
Lee et al., 201716
China
Retrospective cohort
Wei et al., 201817
China
Prospective cohort
Zhang et al., 201718
China
Retrospective cohort
19
Huang et al., 2017
China
Retrospective cohort
Lv et al., 201720
China
Retrospective cohort
China
Retrospective cohort
von Eckardstein et al., 2014 Thirumala et al., 201515 Q8
Study Design
21
Song et al., 2019
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Selection Criteria Eligible studies were selected according to the following inclusion criteria: 1) studies including the data about the relation between the disappearance of AMR or LSR during MVD and the relief of primary HFS; 2) peer-reviewed original research articles; 3) studies published with full text in English; and 4) studies published online from their inception until September 30, 2019. Studies that met the following criteria were excluded: 1) studies investigating the correlation between the time of disappearance of AMR or LSR during MVD and the relief of HFS; 2) studies that included patients with secondary HFS; 3) studies with <30 patients; 4) abstracts, editorials, case reports, conference presentations, and expert opinions; 5) duplicate reports including the same patients (the most up-to-date version or the one with most patients was included); and 6) studies not published in English. Data Extraction All data were extracted from the article text, tables, and figures by 2 reviewers independently. Disagreement was resolved by discussion and consensus with other reviewers. Because most studies provided the outcomes of patients in 1 week, 6 months, or 1 year after MVD, the short-
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Figure 2. Risk of bias and applicability concerns graph.
term in the current study was referred to as no more than 1 week, and the long-term as no less than half a year. The following information was extracted from each study: first author, year of publication, country, sample size, study design, the number of patients with the disappearance of AMR during MVD, the number of patients with the persistence of AMR after MVD, the number of patients with the
relief of HFS, and the number of patients with the persistence of HFS.
Quality Assessment of the Included Articles The literature quality was evaluated by 2 reviewers independently using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies).8
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Figure 3. Risk of bias and applicability concerns summary.
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Statistical Analyses Pooled relative risk (RR) with 95% confidence interval (CI) was used to evaluate the association between the disappearance of AMR and the relief of HFS. The sensitivity, specificity, positive likelihood ratio (LRP), negative likelihood ratio (LRN), and diagnostic odds ratio (DOR) were pooled to estimate the prediction power of the disappearance of AMR on the short-term and the long-term surgical outcomes of patients with HFS. Heterogeneity between studies was evaluated using the Cochran Q-test and I2 index. I2 >50% was considered highly heterogeneous, and the random effects model was used for meta-analysis; otherwise, the fixed effects model was used. To further analyze the sources of heterogeneity, the meta-regression analysis was performed according to publication year, sample size, country, and study design. We calculated the summary receiver operating characteristic curves and area under the curve (AUC) of the disappearance of AMR with 95% CI. A sensitivity analysis was conducted by excluding 1 study at a time to evaluate the effect of individual studies on the pooled estimates. Publication bias was estimated using the Begg test, the Egger test, and funnel plots. Nonparametric trim-and-fill analysis was conducted to rectify the impact of publication bias. The Deek funnel plot and its asymmetry test, which were conducted by a regression of logarithm of DOR against 1/sqrt (effective sample size) and weighting by effective sample size, with P < 0.05 for the slope coefficient indicating significant asymmetry, were used to investigate the publication bias of the
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RESULTS
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Literature Retrieved The initial literature search found 539 potentially relevant publications. A total of 394 records were removed because of duplication. A total of 35 articles were retrieved for eligibility assessment after excluding irrelevant articles by reading the titles and abstracts. A total of 21 articles were eliminated after browsing the full text according to the inclusion and exclusion criteria. No additional studies were obtained through reviewing the reference lists. Ultimately, 14 articles were included in the meta-analysis (Figure 1).6,9-21
Figure 4. Forest plot of the association between the disappearance of abnormal muscle response (AMR) and short-term outcome. AMR-disa, number of patients with the disappearance of AMR during microvascular decompression (MVD); AMR-pers, number of patients with the persistence after MVD; CI, confidence interval.
diagnostic accuracy test. Two-tailed P values < 0.05 were considered statistically significant. Statistical analyses were performed using STATA software version 16.0 (STATA Corp., College Station,
Texas, USA) with the MIDAS module. The quality assessment of included studies was conducted using Review Manager, version 5.3 (Cochrane Collaboration, Copenhagen, Denmark).
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Figure 5. Summary receiver operating characteristic (SROC) curve for the 12 included studies regarding the short-term outcome. Numbers in brackets are 95% confidence interval. AUC, area under the curve; SENS, sensitivity; SPEC, specificity.
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Study Characteristics The major characteristics of the included studies are presented in Table 1. The 14 studies were published between 2005 and 2019, of which 8 studies were conducted Q 4 in China, 2 in Japan, 2 in South Korea, 1 in Germany, and 1 in the United States. Thirteen studies adopted a retrospective cohort design, and only 1 study followed a prospective cohort design. Quality Assessment of the Included Studies The quality assessment of the included studies is illustrated in Figures 2 and 3. Seven studies were judged to be at low risk of bias and 5 at high risk, and 2 at unclear risk in the patient selection domain; 10 studies were regarded as low risk of bias and 4 as high risk in the flow and timing domain; all studies were judged to be at low risk of bias in the index test domain and the reference standard domain. All studies were evaluated as low risk in terms of the applicability concerns. Association Between AMR and ShortTerm Outcome Twelve studies9-11,13-21 including 3957 patients were eligible for data extraction and meta-analysis of the prognostic value of AMR for the short-term outcome of patients with HFS. A random effects model was used to calculate the pooled RRs and 95% CIs due to high heterogeneity between studies (I2 ¼ 64.44%). The disappearance of AMR during MVD was associated with a favorable short-term surgical outcome (pooled RR, 1.42; 95% CI, 1.24e1.62) (Figure 4). The pooled
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Association of AMR and Long-Term Outcomes Thirteen studies6,9-19,21 including 3775 patients were eligible for data extraction and meta-analysis of the prognostic value of AMR for the long-term outcome of patients with HFS. Because there was high heterogeneity between studies (I2 ¼ 54.35%), a random effects model was used to calculate the pooled RRs and 95% CIs. The disappearance of AMR during MVD was almost ineffective in predicting the long-term outcome of patients with HFS (pooled RR, 1.09; 95% CI, 1.02e1.17) (Figure 6). The pooled sensitivity, specificity, LRP, LRN, and DOR were 0.90 (95% CI, 0.85e0.93), 0.28 (95% CI, 0.20e0.37), 1.2 (95% CI, 1.1e1.4), 0.38 (95% CI, 0.22e0.63), and 3 (95% CI, 2e6), respectively. The AUC was 0.58 (95% CI, 0.53e0.62) (Figure 7). Figure 6. Forest plot of the association between the disappearance of abnormal muscle response (AMR) and the long-term outcome. AMR-disa, number of patients with the disappearance of AMR during microvascular decompression (MVD); AMR-pers, number of patients with the persistence after MVD; CI, confidence interval.
sensitivity, specificity, LRP, LRN, and DOR were 0.91 (95% CI, 0.88e0.94), 0.34 (95% CI, 0.27e0.42), 1.4 (95% CI, 1.2e1.6), 0.26 (95% CI, 0.17e0.38), and 5
(95% CI, 3e9), respectively. The overall area under the summary receiver operating characteristic curve (i.e., AUC) was 0.72 (95% CI, 0.68e0.76) (Figure 5).
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Figure 7. Summary receiver operating characteristic (SROC) curve for the 13 included studies regarding the long-term outcome. Numbers in brackets are 95% confidence interval. AUC, area under the curve; SENS, sensitivity; SPEC, specificity.
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Heterogeneity and Publication Bias Assessment We conducted meta-regression analysis according to the study design (prospective vs. retrospective), country (China vs. other countries), publication year (prior 2015 vs. after 2015), and sample size (<100 vs. Q 5 >100) for the purpose of identifying the possible sources of heterogeneity between these studies. The meta-regression analysis showed that no factors earlier mentioned account for the source of heterogeneity in the meta-analysis regarding either the short-term or the long-term outcome. In respect to the pooled RR in the metaanalysis regarding the short-term outcome, the funnel plot showed there was publication bias between studies, and the potential publication bias was confirmed by the Begg test (P ¼ 0.040) and the Egger test (P ¼ 0.013). The nonparametric trim-and-fill analysis was performed to rectify the impact of publication bias, and the pooled RR adjusted for publication bias declined to 1.30 (95% CI, 1.08e1.57). With regard to the pooled RR in the meta-analysis regarding the long-term outcome, there may also be publication bias according to the visual assessment of funnel plots, and the potential publication bias was confirmed by the Egger test (P ¼ 0.003), but not confirmed by the Begg test (P ¼ 0.2). Nonparametric trim-and-fill analysis showed that the pooled RR adjusted for
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were 90%, and the negative posttest probabilities were 61% (Figure 10). The overall long-term cure rate of HFS in the studies included in this meta-analysis was 94%. The Fagan plot indicated that when the pretest probabilities were 94%, the positive posttest probabilities were 95%, and the negative posttest probabilities were 85% (Figure 11). Likelihood ratio scatter gram regarding the short-term outcome of patients with HFS and that regarding the long-term outcome both demonstrated the pooled LRP <10 and the pooled LRN >0.1 (Figures 12 and 13). DISCUSSION Figure 8. The Deek funnel plot for publication bias between studies regarding the short-term outcome. ESS, effective sample size.
publication bias was 1.001 (95% CI, 0.92e 1.09), which implies no effect of prediction. In respect to the meta-analysis of diagnostic accuracy test, the Deek funnel plot asymmetry test showed that there was no publication bias regarding either the short-term or the long-term outcome (Figures 8 and 9). Sensitivity Analyses All studies were sequentially removed to evaluate the impact of individual study on the pooled RRs. The pooled RRs of the
disappearance of AMR for the short-term outcome in the sensitivity analysis varied from 1.31e1.48, and that for the long-term outcome varied from 1.077e1.164. The results suggested that the pooled RRs were not significantly affected by individual study. Value of AMR for Clinical Practice The overall short-term cure rate of HFS in the studies included in this meta-analysis was 86%. The Fagan plot demonstrated that when the pretest probabilities were 86%, the positive posttest probabilities
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Figure 9. The Deek funnel plot for publication bias between studies regarding the long-term outcome. ESS, effective sample size.
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MVD has become popular worldwide as an effective treatment modality for HFS, and AMD monitoring is widely employed in an effort to improve its effectiveness.1 Lee et al.16 reported that the AMR monitoring during MVD is beneficial for identifying the offending vessel and suggesting the most appropriate surgical endpoint. Kong et al.10 reported that the monitoring of AMR is an effective tool to use when performing complete decompression, and it may help to predict the outcomes. Nevertheless, divergent views on this issue have always existed. Wei et al.17 evaluated whether the intraoperative monitoring of AMR improves the efficacy of MVD for HFS and found that the intraoperative AMR monitoring did not provide significant benefit with respect to the outcome of MVD for HFS in skilled hands. Although the monitoring of AMR may be useful in many ways, it should be noted that the current meta-analysis focused exclusively on the prognostic value of the disappearance of AMR during MVD for the short-term and the long-term cure rate of HFS. Numerous studies have been published attempting to determine whether the disappearance of AMR during MVD leads to better outcomes. However, these studies yielded conflicting results.5,6,11-13,17,21 The prognostic value of the disappearance of AMR during MVD for surgical outcome remains a topic of debate so far. Therefore we performed a meta-analysis to systematically evaluate the prognostic value of the disappearance of AMR during MVD for the short-term and long-term outcomes on a large scale. As delayed relief of HFS after MVD is not
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Figure 10. The Fagan plot to evaluate the clinical efficacy use of the disappearance of abnormal muscle response in predicting the
rare and the HFS cure rate improves over time,16 the long-term outcome is more clinically important than the short-term outcome. Hence more attention should be paid to the pooled results regarding the long-term outcome. Because studies included in this metaanalysis were of either retrospective or prospective cohort design, and the cure rate of HFS through MVD is extremely high, it is appropriate to use RR rather than odds ratio to evaluate the prognostic value of AMR. In the current study, the pooled RR in the meta-analysis regarding the short-term outcome was 1.42 (95% CI, 1.24e1.62), suggesting that patients with
short-term outcome of patients with hemifacial spasm. LR, likelihood ratio.
the disappearance of AMR tend to have a higher short-term cure rate, although the prognostic value is limited. In other words, the disappearance of AMR is useful in predicting the early relief of HFS after MVD. However, the pooled RR in the meta-analysis regarding the long-term outcome was 1.09 (95% CI, 1.02e1.17), which suggested that the disappearance of AMR is almost ineffective in predicting the long-term outcome. There was significant heterogeneity between studies according to the value of I2 >50%. To identify factors that may have caused the heterogeneity, we further performed a meta-regression analysis.
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Covariates specific to studies and patients were evaluated, however, no factors were recognized to be responsible for the heterogeneity. Thus it is not necessary to further conduct subgroup analysis based on earlier mentioned factors. It is almost impossible to obtain a definitive conclusion about the cause of heterogeneity in meta-analysis. However, fortunately, despite the fact that there was significant heterogeneity between the included studies, the sensitivity analysis showed that the pooled RRs were not significantly affected by individual studies. Therefore the results of the pooled RR in this metaanalysis are robust and thus reliable.
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Figure 11. The Fagan plot to evaluate the clinical efficacy use of the disappearance of abnormal muscle response in predicting the
Publication bias may have affected the reliability of the pooled RR in the current meta-analysis. Thus nonparametric trimand-fill analysis was further conducted to rectify the impact of publication bias. Unfortunately, the pooled RR adjusted for publication bias regarding the short-term outcome declined to 1.3, and that regarding the long-term outcome even declined to 1.001 (95% CI, 0.92e1.09), which were more disappointing than the original results. Additionally, no publication bias regarding the meta-analysis of the diagnostic accuracy test was found, which implied that the pooled results were reliable.
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long-term outcome of patients with hemifacial spasm. LR, likelihood ratio.
The specificity of the disappearance of AMR is low, which suggest that patients with persistence of AMR after MVD will probably also get relief of HFS. Wei et al.17 reported that 85.71% of the patients with persistence of AMR after MVD obtained a satisfactory long-term outcome. The AUC regarding the short-term outcome was 0.72, suggesting moderate diagnostic value, and that regarding the long-term outcome was 0.58, which was suggestive of low diagnostic value. Furthermore, the Fagan plot indicated that the disappearance of AMR had limited prognostic value for the short-term outcome and had low or
even no prognostic value for the long-term outcome. In addition, the likelihood ratio scatter gram regarding the short-term outcome and that regarding the longterm outcome both showed the pooled LRP <10 and the pooled LRN >0.1, which indicated that the disappearance of AMR implies neither exclusion nor confirmation. These results suggested that the disappearance of AMR is insufficiently reliable to predict the surgical outcome and has limited value of clinical application. To be clear, the current meta-analysis appraised the prognostic value of the disappearance of AMR exclusively, and
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cohort studies are warranted to validate our findings. UNCITED REFERENCE 22. REFERENCES 1. Chaudhry N, Srivastava A, Joshi L. Hemifacial spasm: the past, present and future. J Neurol Sci. 2015;356:27-31.
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2. Wilkinson MF, Chowdhury T, Mutch WA, Kaufmann AM. Analysis of facial motor evoked potentials for assessing a central mechanism in hemifacial spasm. J Neurosurg. 2017;126:379-385. 3. Lee S, Park SK, Lee JA, Joo BE, Park K. Missed culprits in failed microvascular decompression surgery for hemifacial spasm and clinical outcomes of redo surgery. World Neurosurg. 2019;129: e627-e633.
Figure 12. The likelihood ratio scatter gram regarding the short-term outcome of patients with hemifacial spasm. LUQ, XXXX; LRP, positive likelihood ratio; RUQ, XXXX; LLQ, XXXX; RLQ, XXXX; LRN, negative likelihood ratio.
4. Shu W, Zhu H, Li Y, Liu R. Clinical analysis of repeat microvascular decompression for recurrent hemifacial spasm. Acta Neurol Belg. 2019;119: 453-459.
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was not to completely deny the value of AMR monitoring during MVD. Our results should be viewed with caution owing to a few limitations. First, there is heterogeneity between the included studies, which to some extent affected the reliability of our pooled analysis. Second, only studies published in English were included. Third, most of the included studies were of retrospective design, which means an unavoidable risk of bias. More well-designed prospective cohort studies are needed. Despite these
limitations, the results of our metaanalysis are rigorous and can provide references for clinical practice. CONCLUSIONS On the basis of the meta-analysis, the disappearance of AMR during MVD demonstrate limited prognostic value for a favorable short-term outcome, and does not appear effective in predicting the longterm outcome of patients with HFS. However, well-designed, prospective
5. El Damaty A, Rosenstengel C, Matthes M, Baldauf J, Schroeder HW. The value of lateral spread response monitoring in predicting the clinical outcome after microvascular decompression in hemifacial spasm: a prospective study on 100 patients. Neurosurg Rev. 2016;39:455-466. 6. von Eckardstein K, Harper C, Castner M, Link M. The significance of intraoperative electromyographic “lateral spread” in predicting outcome of microvascular decompression for hemifacial spasm. J Neurol Surg B Skull Base. 2014;75:198-203. 7. Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ. 2009;339:b2535. 8. Whiting PF, Rutjes AW, Westwood ME, et al. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med. 2011;155:529-536. 9. Yamashita S, Kawaguchi T, Fukuda M, Watanabe M, Tanaka R, Kameyama S. Abnormal muscle response monitoring during microvascular decompression for hemifacial spasm. Acta Neurochir (Wien). 2005;147:933-937 [discussion: 937-938]. 10. Kong DS, Park K, Shin BG, Lee JA, Eum DO. Prognostic value of the lateral spread response for intraoperative electromyography monitoring of the facial musculature during microvascular decompression for hemifacial spasm. J Neurosurg. 2007;106:384-387.
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Figure 13. The likelihood ratio scatter gram regarding the long-term outcome of patients with hemifacial spasm. LUQ, XXXX; LRP, positive likelihood ratio; RUQ, XXXX; LLQ, XXXX; RLQ, XXXX; LRN, negative likelihood ratio.
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11. Joo WI, Lee KJ, Park HK, Chough CK, Rha HK. Prognostic value of intra-operative lateral spread response monitoring during microvascular decompression in patients with hemifacial spasm. J Clin Neurosci. 2008;15:1335-1339. 12. Li J, Zhang Y, Zhu H, Li Y. Prognostic value of intra-operative abnormal muscle response
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monitoring during microvascular decompression for the long-term outcome of hemifacial spasm. J Clin Neurosci. 2012;19:44-48. 13. Ying TT, Li ST, Zhong J, Li XY, Wang XH, Zhu J. The value of abnormal muscle response monitoring during microvascular decompression surgery for hemifacial spasm. Int J Surg. 2011;9: 347-351. 14. Tobishima H, Hatayama T, Ohkuma H. Relation between the persistence of an abnormal muscle response and the long-term clinical course after microvascular decompression for hemifacial spasm. Neurol Med Chir (Tokyo). 2014;54:474-482. 15. Thirumala PD, Wang X, Shah A, et al. Clinical impact of residual lateral spread response after adequate microvascular decompression for hemifacial spasm: a retrospective analysis. Br J Neurosurg. 2015;29:818-822. 16. Lee SH, Park BJ, Shin HS, Park CK, Rhee BA, Lim YJ. Prognostic ability of intraoperative electromyographic monitoring during microvascular decompression for hemifacial spasm to predict
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lateral spread response outcome. J Neurosurg. 2017; 126:391-396. 17. Wei Y, Yang W, Zhao W, et al. Microvascular decompression for hemifacial spasm: can intraoperative lateral spread response monitoring improve surgical efficacy? J Neurosurg. 2018;128: 885-890. 18. Zhang X, Zhao H, Tang YD, et al. The effects of combined intraoperative monitoring of abnormal muscle response and Z-L response for hemifacial spasm. World Neurosurg. 2017;108:367-373. 19. Huang C, Miao S, Chu H, et al. An optimized abnormal muscle response recording method for intraoperative monitoring of hemifacial spasm and its long-term prognostic value. Int J Surg. 2017; 38:67-73.
microvascular decompression for hemifacial spasm. J Int Med Res. 2019;47:6120-6128.
22. Dannenbaum M, Lega BC, Suki D, Harper RL, Yoshor D. Microvascular decompression for hemifacial spasm: long-term results from 114 operations performed without neurophysiological Q6 monitoring. J Neurosurg. 2008;109:410-415.
Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Received 31 October 2019; accepted 21 January 2020 Citation: World Neurosurg. (2020). https://doi.org/10.1016/j.wneu.2020.01.166
20. Lv MY, Deng SL, Long XF, Liu ZL. Long-term outcome of microvascular decompression for hemifacial spasm. Br J Neurosurg. 2017;31:322-326.
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21. Song H, Xu S, Fan X, Yu M, Feng J, Sun L. Prognostic value of lateral spread response during
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Prognostic Value of Abnormal Muscle Response During Microvascular Decompression for Hemifacial Spasm: A Meta-Analysis Jie Zhang1, Zong-Hao Li2, Jin-Feng Wang1, Yong-Han Chen2, Ning Wang1, Yi Wang2
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- OBJECTIVE:
To perform a comprehensive meta-analysis to systematically assess the value of abnormal muscle response (AMR) in predicting the surgical outcome of patients with hemifacial spasm.
Key words Abnormal muscle response - Hemifacial spasm - Lateral spread response - Microvascular decompression -
- METHODS:
Abbreviations and Acronyms AMR: Abnormal muscle response AUC: Area under the curve CI: Confidence interval DOR: Diagnostic odds ratio HFS: Hemifacial spasm LRN: Negative likelihood ratio LRP: Positive likelihood ratio LSR: Lateral spread response MVD: Microvascular decompression Q2 RR: Relative risk From the Departments of 1Neuroelectrophysiology and Neurosurgery, Cangzhou Central Hospital, Yunhe District, Cangzhou, Hebei, People’s Republic of China
2
To whom correspondence should be addressed: Zong-Hao Li, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2020). https://doi.org/10.1016/j.wneu.2020.01.166 Journal homepage: www.journals.elsevier.com/worldneurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2020 Elsevier Inc. All rights reserved.
The electronic database PubMed, Embase, Web of Science, and ScienceDirect were searched, and relevant articles were identified up to September 30, 2019. These data were extracted for pooled analysis, heterogeneity testing, sensitivity analysis, publication bias analysis, and Fagan plot analysis.
- RESULTS:
The disappearance of AMR during microvascular decompression was associated with a favorable short-term surgical outcome (pooled relative risk [RR], 1.42; 95% confidence interval [CI], 1.24e1.62; pooled RR adjusted for publication bias, 1.30; 95% CI, 1.08e1.57). The corresponding pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.91 (95% CI, 0.88e0.94), 0.34 (95% CI, 0.27e0.42), 1.4 (95% CI, 1.2e1.6), 0.26 (95% CI, 0.17e0.38), and 5 (95% CI, 3e9), respectively. The disappearance of AMR was almost ineffective in predicting the long-term surgical outcome (pooled RR, 1.09; 95% CI, 1.02e1.17; pooled RR adjusted for publication bias, 1.001; 95% CI, 0.92e1.09). The corresponding pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.90 (95% CI, 0.85e0.93), 0.28 (95% CI, 0.20e0.37), 1.2 (95% CI, 1.1e1.4), 0.38 (95% CI, 0.22e0.63), and 3 (95% CI, 2e6), respectively.
- CONCLUSIONS:
The disappearance of AMR during microvascular decompression demonstrates limited prognostic value for a favorable short-term outcome, and does not appear effective in predicting the long-term outcome of patients with hemifacial spasm.
INTRODUCTION Hemifacial spasm (HFS) is a neuromuscular disorder characterized by involuntary contraction of facial muscles, can result in increasing embarrassment and social withdrawal for the individual, and even functional blindness due to involuntary eye closure in severe cases.1 Although the exact mechanism of HFS remains unclear, the primary cause of this disorder is considered to be vascular compression of the facial nerve root entry zone.2 Microvascular decompression (MVD) is a highly effective and safe treatment modality and has been established as the goldstandard treatment for HFS based on its etiology. However, the results of MVD are not always satisfactory.3,4 Abnormal
muscle response (AMR), also known as the lateral spread response (LSR), is an abnormal electrophysiological characteristic and can be elicited by stimulating 1 branch of the facial nerve and simultaneously recording from muscles innervated by other branches of the facial nerve in patients with HFS. It usually disappears after adequate decompression of the facial nerve from neurovascular contact and may thus facilitate the confirmation of adequate decompression. Accordingly, AMR monitoring is widely performed to guide the surgeon during MVD and to predict the surgical outcome of patients with HFS. However, some investigators
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questioned the reliability of AMR because the disappearance of AMR does not always lead to the relief of HFS, although the persistence of AMR does Q 3 not definitely mean the operation failed. Overall, the prognostic value of the disappearance of AMR remains vague and controversial.5,6 Therefore we conducted a meta-analysis to evaluate the value of the disappearance of AMR during MVD in predicting the outcomes of patients with HFS. METHODS This study was performed according to the Preferred Reporting Items for Systematic
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Literature Search Strategy A systematic literature search was performed in PubMed, Embase, Web of Science, and ScienceDirect using Medical Subject Headings and general search terms from their date of inception until September 30, 2019 to identify relevant studies. The search strategy used different combinations of the following terms: “hemifacial spasm,” “abnormal muscle response,” “lateral spread response,” “electrophysiological,” and “microvascular decompression.” The records retrieved from electronic databases were first screened by the titles and abstracts, and then full-text articles of relevant studies were retrieved for further review. Manual searches were conducted in the reference lists of relevant articles to obtain additional articles. A literature search was conducted by 2 reviewers independently, and they then reviewed and selected articles for further analysis. Disagreement was resolved by discussion with other reviewers.
Figure 1. Flow chart of selection process to enroll eligible studies.
Reviews and Meta-Analyses (PRISMA) guidelines.7 All results and analysis were based on previously published studies,
and thus there was no need to seek further ethical approval and patient consent.
Table 1. Characteristics of Included Studies Study
Country
Yamashita et al., 20059
Japan
Retrospective cohort
Kong et al., 200710
South Korea
Retrospective cohort
Joo et al., 200811
China
Retrospective cohort
12
Li et al., 2012
Japan
Retrospective cohort
Ying et al., 201113
China
Retrospective cohort
United States
Retrospective cohort
Tobishima et al., 201414 6
Germany
Retrospective cohort
South Korea
Retrospective cohort
Lee et al., 201716
China
Retrospective cohort
Wei et al., 201817
China
Prospective cohort
Zhang et al., 201718
China
Retrospective cohort
19
Huang et al., 2017
China
Retrospective cohort
Lv et al., 201720
China
Retrospective cohort
China
Retrospective cohort
von Eckardstein et al., 2014 Thirumala et al., 201515 Q8
Study Design
21
Song et al., 2019
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Selection Criteria Eligible studies were selected according to the following inclusion criteria: 1) studies including the data about the relation between the disappearance of AMR or LSR during MVD and the relief of primary HFS; 2) peer-reviewed original research articles; 3) studies published with full text in English; and 4) studies published online from their inception until September 30, 2019. Studies that met the following criteria were excluded: 1) studies investigating the correlation between the time of disappearance of AMR or LSR during MVD and the relief of HFS; 2) studies that included patients with secondary HFS; 3) studies with <30 patients; 4) abstracts, editorials, case reports, conference presentations, and expert opinions; 5) duplicate reports including the same patients (the most up-to-date version or the one with most patients was included); and 6) studies not published in English. Data Extraction All data were extracted from the article text, tables, and figures by 2 reviewers independently. Disagreement was resolved by discussion and consensus with other reviewers. Because most studies provided the outcomes of patients in 1 week, 6 months, or 1 year after MVD, the short-
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Figure 2. Risk of bias and applicability concerns graph.
term in the current study was referred to as no more than 1 week, and the long-term as no less than half a year. The following information was extracted from each study: first author, year of publication, country, sample size, study design, the number of patients with the disappearance of AMR during MVD, the number of patients with the persistence of AMR after MVD, the number of patients with the
relief of HFS, and the number of patients with the persistence of HFS.
Quality Assessment of the Included Articles The literature quality was evaluated by 2 reviewers independently using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies).8
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Figure 3. Risk of bias and applicability concerns summary.
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Statistical Analyses Pooled relative risk (RR) with 95% confidence interval (CI) was used to evaluate the association between the disappearance of AMR and the relief of HFS. The sensitivity, specificity, positive likelihood ratio (LRP), negative likelihood ratio (LRN), and diagnostic odds ratio (DOR) were pooled to estimate the prediction power of the disappearance of AMR on the short-term and the long-term surgical outcomes of patients with HFS. Heterogeneity between studies was evaluated using the Cochran Q-test and I2 index. I2 >50% was considered highly heterogeneous, and the random effects model was used for meta-analysis; otherwise, the fixed effects model was used. To further analyze the sources of heterogeneity, the meta-regression analysis was performed according to publication year, sample size, country, and study design. We calculated the summary receiver operating characteristic curves and area under the curve (AUC) of the disappearance of AMR with 95% CI. A sensitivity analysis was conducted by excluding 1 study at a time to evaluate the effect of individual studies on the pooled estimates. Publication bias was estimated using the Begg test, the Egger test, and funnel plots. Nonparametric trim-and-fill analysis was conducted to rectify the impact of publication bias. The Deek funnel plot and its asymmetry test, which were conducted by a regression of logarithm of DOR against 1/sqrt (effective sample size) and weighting by effective sample size, with P < 0.05 for the slope coefficient indicating significant asymmetry, were used to investigate the publication bias of the
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RESULTS
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Literature Retrieved The initial literature search found 539 potentially relevant publications. A total of 394 records were removed because of duplication. A total of 35 articles were retrieved for eligibility assessment after excluding irrelevant articles by reading the titles and abstracts. A total of 21 articles were eliminated after browsing the full text according to the inclusion and exclusion criteria. No additional studies were obtained through reviewing the reference lists. Ultimately, 14 articles were included in the meta-analysis (Figure 1).6,9-21
Figure 4. Forest plot of the association between the disappearance of abnormal muscle response (AMR) and short-term outcome. AMR-disa, number of patients with the disappearance of AMR during microvascular decompression (MVD); AMR-pers, number of patients with the persistence after MVD; CI, confidence interval.
diagnostic accuracy test. Two-tailed P values < 0.05 were considered statistically significant. Statistical analyses were performed using STATA software version 16.0 (STATA Corp., College Station,
Texas, USA) with the MIDAS module. The quality assessment of included studies was conducted using Review Manager, version 5.3 (Cochrane Collaboration, Copenhagen, Denmark).
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Figure 5. Summary receiver operating characteristic (SROC) curve for the 12 included studies regarding the short-term outcome. Numbers in brackets are 95% confidence interval. AUC, area under the curve; SENS, sensitivity; SPEC, specificity.
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Study Characteristics The major characteristics of the included studies are presented in Table 1. The 14 studies were published between 2005 and 2019, of which 8 studies were conducted Q 4 in China, 2 in Japan, 2 in South Korea, 1 in Germany, and 1 in the United States. Thirteen studies adopted a retrospective cohort design, and only 1 study followed a prospective cohort design. Quality Assessment of the Included Studies The quality assessment of the included studies is illustrated in Figures 2 and 3. Seven studies were judged to be at low risk of bias and 5 at high risk, and 2 at unclear risk in the patient selection domain; 10 studies were regarded as low risk of bias and 4 as high risk in the flow and timing domain; all studies were judged to be at low risk of bias in the index test domain and the reference standard domain. All studies were evaluated as low risk in terms of the applicability concerns. Association Between AMR and ShortTerm Outcome Twelve studies9-11,13-21 including 3957 patients were eligible for data extraction and meta-analysis of the prognostic value of AMR for the short-term outcome of patients with HFS. A random effects model was used to calculate the pooled RRs and 95% CIs due to high heterogeneity between studies (I2 ¼ 64.44%). The disappearance of AMR during MVD was associated with a favorable short-term surgical outcome (pooled RR, 1.42; 95% CI, 1.24e1.62) (Figure 4). The pooled
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Association of AMR and Long-Term Outcomes Thirteen studies6,9-19,21 including 3775 patients were eligible for data extraction and meta-analysis of the prognostic value of AMR for the long-term outcome of patients with HFS. Because there was high heterogeneity between studies (I2 ¼ 54.35%), a random effects model was used to calculate the pooled RRs and 95% CIs. The disappearance of AMR during MVD was almost ineffective in predicting the long-term outcome of patients with HFS (pooled RR, 1.09; 95% CI, 1.02e1.17) (Figure 6). The pooled sensitivity, specificity, LRP, LRN, and DOR were 0.90 (95% CI, 0.85e0.93), 0.28 (95% CI, 0.20e0.37), 1.2 (95% CI, 1.1e1.4), 0.38 (95% CI, 0.22e0.63), and 3 (95% CI, 2e6), respectively. The AUC was 0.58 (95% CI, 0.53e0.62) (Figure 7). Figure 6. Forest plot of the association between the disappearance of abnormal muscle response (AMR) and the long-term outcome. AMR-disa, number of patients with the disappearance of AMR during microvascular decompression (MVD); AMR-pers, number of patients with the persistence after MVD; CI, confidence interval.
sensitivity, specificity, LRP, LRN, and DOR were 0.91 (95% CI, 0.88e0.94), 0.34 (95% CI, 0.27e0.42), 1.4 (95% CI, 1.2e1.6), 0.26 (95% CI, 0.17e0.38), and 5
(95% CI, 3e9), respectively. The overall area under the summary receiver operating characteristic curve (i.e., AUC) was 0.72 (95% CI, 0.68e0.76) (Figure 5).
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Figure 7. Summary receiver operating characteristic (SROC) curve for the 13 included studies regarding the long-term outcome. Numbers in brackets are 95% confidence interval. AUC, area under the curve; SENS, sensitivity; SPEC, specificity.
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Heterogeneity and Publication Bias Assessment We conducted meta-regression analysis according to the study design (prospective vs. retrospective), country (China vs. other countries), publication year (prior 2015 vs. after 2015), and sample size (<100 vs. Q 5 >100) for the purpose of identifying the possible sources of heterogeneity between these studies. The meta-regression analysis showed that no factors earlier mentioned account for the source of heterogeneity in the meta-analysis regarding either the short-term or the long-term outcome. In respect to the pooled RR in the metaanalysis regarding the short-term outcome, the funnel plot showed there was publication bias between studies, and the potential publication bias was confirmed by the Begg test (P ¼ 0.040) and the Egger test (P ¼ 0.013). The nonparametric trim-and-fill analysis was performed to rectify the impact of publication bias, and the pooled RR adjusted for publication bias declined to 1.30 (95% CI, 1.08e1.57). With regard to the pooled RR in the meta-analysis regarding the long-term outcome, there may also be publication bias according to the visual assessment of funnel plots, and the potential publication bias was confirmed by the Egger test (P ¼ 0.003), but not confirmed by the Begg test (P ¼ 0.2). Nonparametric trim-and-fill analysis showed that the pooled RR adjusted for
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were 90%, and the negative posttest probabilities were 61% (Figure 10). The overall long-term cure rate of HFS in the studies included in this meta-analysis was 94%. The Fagan plot indicated that when the pretest probabilities were 94%, the positive posttest probabilities were 95%, and the negative posttest probabilities were 85% (Figure 11). Likelihood ratio scatter gram regarding the short-term outcome of patients with HFS and that regarding the long-term outcome both demonstrated the pooled LRP <10 and the pooled LRN >0.1 (Figures 12 and 13). DISCUSSION Figure 8. The Deek funnel plot for publication bias between studies regarding the short-term outcome. ESS, effective sample size.
publication bias was 1.001 (95% CI, 0.92e 1.09), which implies no effect of prediction. In respect to the meta-analysis of diagnostic accuracy test, the Deek funnel plot asymmetry test showed that there was no publication bias regarding either the short-term or the long-term outcome (Figures 8 and 9). Sensitivity Analyses All studies were sequentially removed to evaluate the impact of individual study on the pooled RRs. The pooled RRs of the
disappearance of AMR for the short-term outcome in the sensitivity analysis varied from 1.31e1.48, and that for the long-term outcome varied from 1.077e1.164. The results suggested that the pooled RRs were not significantly affected by individual study. Value of AMR for Clinical Practice The overall short-term cure rate of HFS in the studies included in this meta-analysis was 86%. The Fagan plot demonstrated that when the pretest probabilities were 86%, the positive posttest probabilities
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Figure 9. The Deek funnel plot for publication bias between studies regarding the long-term outcome. ESS, effective sample size.
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MVD has become popular worldwide as an effective treatment modality for HFS, and AMD monitoring is widely employed in an effort to improve its effectiveness.1 Lee et al.16 reported that the AMR monitoring during MVD is beneficial for identifying the offending vessel and suggesting the most appropriate surgical endpoint. Kong et al.10 reported that the monitoring of AMR is an effective tool to use when performing complete decompression, and it may help to predict the outcomes. Nevertheless, divergent views on this issue have always existed. Wei et al.17 evaluated whether the intraoperative monitoring of AMR improves the efficacy of MVD for HFS and found that the intraoperative AMR monitoring did not provide significant benefit with respect to the outcome of MVD for HFS in skilled hands. Although the monitoring of AMR may be useful in many ways, it should be noted that the current meta-analysis focused exclusively on the prognostic value of the disappearance of AMR during MVD for the short-term and the long-term cure rate of HFS. Numerous studies have been published attempting to determine whether the disappearance of AMR during MVD leads to better outcomes. However, these studies yielded conflicting results.5,6,11-13,17,21 The prognostic value of the disappearance of AMR during MVD for surgical outcome remains a topic of debate so far. Therefore we performed a meta-analysis to systematically evaluate the prognostic value of the disappearance of AMR during MVD for the short-term and long-term outcomes on a large scale. As delayed relief of HFS after MVD is not
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Figure 10. The Fagan plot to evaluate the clinical efficacy use of the disappearance of abnormal muscle response in predicting the
rare and the HFS cure rate improves over time,16 the long-term outcome is more clinically important than the short-term outcome. Hence more attention should be paid to the pooled results regarding the long-term outcome. Because studies included in this metaanalysis were of either retrospective or prospective cohort design, and the cure rate of HFS through MVD is extremely high, it is appropriate to use RR rather than odds ratio to evaluate the prognostic value of AMR. In the current study, the pooled RR in the meta-analysis regarding the short-term outcome was 1.42 (95% CI, 1.24e1.62), suggesting that patients with
short-term outcome of patients with hemifacial spasm. LR, likelihood ratio.
the disappearance of AMR tend to have a higher short-term cure rate, although the prognostic value is limited. In other words, the disappearance of AMR is useful in predicting the early relief of HFS after MVD. However, the pooled RR in the meta-analysis regarding the long-term outcome was 1.09 (95% CI, 1.02e1.17), which suggested that the disappearance of AMR is almost ineffective in predicting the long-term outcome. There was significant heterogeneity between studies according to the value of I2 >50%. To identify factors that may have caused the heterogeneity, we further performed a meta-regression analysis.
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Covariates specific to studies and patients were evaluated, however, no factors were recognized to be responsible for the heterogeneity. Thus it is not necessary to further conduct subgroup analysis based on earlier mentioned factors. It is almost impossible to obtain a definitive conclusion about the cause of heterogeneity in meta-analysis. However, fortunately, despite the fact that there was significant heterogeneity between the included studies, the sensitivity analysis showed that the pooled RRs were not significantly affected by individual studies. Therefore the results of the pooled RR in this metaanalysis are robust and thus reliable.
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Figure 11. The Fagan plot to evaluate the clinical efficacy use of the disappearance of abnormal muscle response in predicting the
Publication bias may have affected the reliability of the pooled RR in the current meta-analysis. Thus nonparametric trimand-fill analysis was further conducted to rectify the impact of publication bias. Unfortunately, the pooled RR adjusted for publication bias regarding the short-term outcome declined to 1.3, and that regarding the long-term outcome even declined to 1.001 (95% CI, 0.92e1.09), which were more disappointing than the original results. Additionally, no publication bias regarding the meta-analysis of the diagnostic accuracy test was found, which implied that the pooled results were reliable.
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long-term outcome of patients with hemifacial spasm. LR, likelihood ratio.
The specificity of the disappearance of AMR is low, which suggest that patients with persistence of AMR after MVD will probably also get relief of HFS. Wei et al.17 reported that 85.71% of the patients with persistence of AMR after MVD obtained a satisfactory long-term outcome. The AUC regarding the short-term outcome was 0.72, suggesting moderate diagnostic value, and that regarding the long-term outcome was 0.58, which was suggestive of low diagnostic value. Furthermore, the Fagan plot indicated that the disappearance of AMR had limited prognostic value for the short-term outcome and had low or
even no prognostic value for the long-term outcome. In addition, the likelihood ratio scatter gram regarding the short-term outcome and that regarding the longterm outcome both showed the pooled LRP <10 and the pooled LRN >0.1, which indicated that the disappearance of AMR implies neither exclusion nor confirmation. These results suggested that the disappearance of AMR is insufficiently reliable to predict the surgical outcome and has limited value of clinical application. To be clear, the current meta-analysis appraised the prognostic value of the disappearance of AMR exclusively, and
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cohort studies are warranted to validate our findings. UNCITED REFERENCE 22. REFERENCES 1. Chaudhry N, Srivastava A, Joshi L. Hemifacial spasm: the past, present and future. J Neurol Sci. 2015;356:27-31.
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2. Wilkinson MF, Chowdhury T, Mutch WA, Kaufmann AM. Analysis of facial motor evoked potentials for assessing a central mechanism in hemifacial spasm. J Neurosurg. 2017;126:379-385. 3. Lee S, Park SK, Lee JA, Joo BE, Park K. Missed culprits in failed microvascular decompression surgery for hemifacial spasm and clinical outcomes of redo surgery. World Neurosurg. 2019;129: e627-e633.
Figure 12. The likelihood ratio scatter gram regarding the short-term outcome of patients with hemifacial spasm. LUQ, XXXX; LRP, positive likelihood ratio; RUQ, XXXX; LLQ, XXXX; RLQ, XXXX; LRN, negative likelihood ratio.
4. Shu W, Zhu H, Li Y, Liu R. Clinical analysis of repeat microvascular decompression for recurrent hemifacial spasm. Acta Neurol Belg. 2019;119: 453-459.
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was not to completely deny the value of AMR monitoring during MVD. Our results should be viewed with caution owing to a few limitations. First, there is heterogeneity between the included studies, which to some extent affected the reliability of our pooled analysis. Second, only studies published in English were included. Third, most of the included studies were of retrospective design, which means an unavoidable risk of bias. More well-designed prospective cohort studies are needed. Despite these
limitations, the results of our metaanalysis are rigorous and can provide references for clinical practice. CONCLUSIONS On the basis of the meta-analysis, the disappearance of AMR during MVD demonstrate limited prognostic value for a favorable short-term outcome, and does not appear effective in predicting the longterm outcome of patients with HFS. However, well-designed, prospective
5. El Damaty A, Rosenstengel C, Matthes M, Baldauf J, Schroeder HW. The value of lateral spread response monitoring in predicting the clinical outcome after microvascular decompression in hemifacial spasm: a prospective study on 100 patients. Neurosurg Rev. 2016;39:455-466. 6. von Eckardstein K, Harper C, Castner M, Link M. The significance of intraoperative electromyographic “lateral spread” in predicting outcome of microvascular decompression for hemifacial spasm. J Neurol Surg B Skull Base. 2014;75:198-203. 7. Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ. 2009;339:b2535. 8. Whiting PF, Rutjes AW, Westwood ME, et al. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med. 2011;155:529-536. 9. Yamashita S, Kawaguchi T, Fukuda M, Watanabe M, Tanaka R, Kameyama S. Abnormal muscle response monitoring during microvascular decompression for hemifacial spasm. Acta Neurochir (Wien). 2005;147:933-937 [discussion: 937-938]. 10. Kong DS, Park K, Shin BG, Lee JA, Eum DO. Prognostic value of the lateral spread response for intraoperative electromyography monitoring of the facial musculature during microvascular decompression for hemifacial spasm. J Neurosurg. 2007;106:384-387.
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Figure 13. The likelihood ratio scatter gram regarding the long-term outcome of patients with hemifacial spasm. LUQ, XXXX; LRP, positive likelihood ratio; RUQ, XXXX; LLQ, XXXX; RLQ, XXXX; LRN, negative likelihood ratio.
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11. Joo WI, Lee KJ, Park HK, Chough CK, Rha HK. Prognostic value of intra-operative lateral spread response monitoring during microvascular decompression in patients with hemifacial spasm. J Clin Neurosci. 2008;15:1335-1339. 12. Li J, Zhang Y, Zhu H, Li Y. Prognostic value of intra-operative abnormal muscle response
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monitoring during microvascular decompression for the long-term outcome of hemifacial spasm. J Clin Neurosci. 2012;19:44-48. 13. Ying TT, Li ST, Zhong J, Li XY, Wang XH, Zhu J. The value of abnormal muscle response monitoring during microvascular decompression surgery for hemifacial spasm. Int J Surg. 2011;9: 347-351. 14. Tobishima H, Hatayama T, Ohkuma H. Relation between the persistence of an abnormal muscle response and the long-term clinical course after microvascular decompression for hemifacial spasm. Neurol Med Chir (Tokyo). 2014;54:474-482. 15. Thirumala PD, Wang X, Shah A, et al. Clinical impact of residual lateral spread response after adequate microvascular decompression for hemifacial spasm: a retrospective analysis. Br J Neurosurg. 2015;29:818-822. 16. Lee SH, Park BJ, Shin HS, Park CK, Rhee BA, Lim YJ. Prognostic ability of intraoperative electromyographic monitoring during microvascular decompression for hemifacial spasm to predict
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lateral spread response outcome. J Neurosurg. 2017; 126:391-396. 17. Wei Y, Yang W, Zhao W, et al. Microvascular decompression for hemifacial spasm: can intraoperative lateral spread response monitoring improve surgical efficacy? J Neurosurg. 2018;128: 885-890. 18. Zhang X, Zhao H, Tang YD, et al. The effects of combined intraoperative monitoring of abnormal muscle response and Z-L response for hemifacial spasm. World Neurosurg. 2017;108:367-373. 19. Huang C, Miao S, Chu H, et al. An optimized abnormal muscle response recording method for intraoperative monitoring of hemifacial spasm and its long-term prognostic value. Int J Surg. 2017; 38:67-73.
microvascular decompression for hemifacial spasm. J Int Med Res. 2019;47:6120-6128.
22. Dannenbaum M, Lega BC, Suki D, Harper RL, Yoshor D. Microvascular decompression for hemifacial spasm: long-term results from 114 operations performed without neurophysiological Q6 monitoring. J Neurosurg. 2008;109:410-415.
Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Received 31 October 2019; accepted 21 January 2020 Citation: World Neurosurg. (2020). https://doi.org/10.1016/j.wneu.2020.01.166
20. Lv MY, Deng SL, Long XF, Liu ZL. Long-term outcome of microvascular decompression for hemifacial spasm. Br J Neurosurg. 2017;31:322-326.
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21. Song H, Xu S, Fan X, Yu M, Feng J, Sun L. Prognostic value of lateral spread response during
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