Structural changes in the CNS of patients with hemifacial spasm

Prediction of Hemifacial Spasm Re-Appearing Phenomenon after Microvascular Decompression Surgery in Patients with Hemifacial Spasm Using Dynamic Susceptibility Contrast Perfusion Magnetic Resonance Imaging

OBJECTIVE

Hemifacial spasm (HFS) is treated by a surgical procedure called microvascular decompression (MVD). However, HFS re-appearing phenomenon after surgery, presenting as early recurrence, is experienced by some patients after MVD. Dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging (MRI) and two analytical methods : receiver operating characteristic (ROC) curve and machine learning, were used to predict early recurrence in this study.

METHODS

This study enrolled 60 patients who underwent MVD for HFS. They were divided into two groups : group A consisted of 32 patients who had early recurrence and group B consisted of 28 patients who had no early recurrence of HFS. DSC perfusion MRI was undergone by all patients before the surgery to obtain the several parameters. ROC curve and machine learning methods were used to predict early recurrence using these parameters.

RESULTS

Group A had significantly lower relative cerebral blood flow than group B in most of the selected brain regions, as shown by the region-of-interest-based analysis. By combining three extraction fraction (EF) values at middle temporal gyrus, posterior cingulate, and brainstem, with age, using naive Bayes machine learning method, the best prediction model for early recurrence was obtained. This model had an area under the curve value of 0.845.

CONCLUSION

By combining EF values with age or sex using machine learning methods, DSC perfusion MRI can be used to predict early recurrence before MVD surgery. This may help neurosurgeons to identify patients who are at risk of HFS recurrence and provide appropriate postoperative care.

Efficacy and safety of botulinum neurotoxin in the treatment of hemifacial spasms: a systematic review and meta-analysis

BACKGROUND

Hemifacial spasm (HFS) is a neuromuscular disorder characterized by unilateral facial muscle spasms, negatively impacts quality of life due to social embarrassment. Botulinum Neurotoxin (BoNT) injections have emerged as a viable therapeutic approach. This systematic review evaluated the efficacy and safety of BoNT injections for HFS management, along with effects on patients' quality of life and mental health.

MATERIALS AND METHODS

A systematic search for studies on BoNT treatment for HFS published between January 1, 2000, and May 1, 2024, was performed across major databases. Study quality was evaluated using Cochrane and Joanna Briggs Institute (JBI) tools, with data management handled by EndNote X9 and statistical analyses conducted via Review Manager (RevMan 5.4) and STATA 14.0.

RESULTS

Thirty-five studies met the inclusion criteria: 2 RCTs comprising 83 HFS patients compared the efficacy of perioral injections of botulinum toxin and placebo, while 33 single-arm studies reported outcomes for 2786 patients post-BoNT injection. The selection of 17 single-arm studies focused on the effectiveness rate as the key outcome metric. Pooled estimate signified a remarkably high effectiveness (ES: 0.882, 95% CI: 0.830, 0.926, P < 0.001). Analysis of depression scale (SMD: -0.85, 95% CI: -1.34, -0.35, P < 0.001), anxiety scale (SMD: -1.50, 95% CI: -2.19, -0.80, P < 0.001) and total scale of quality of life (SMD: -0.64, 95% CI: -0.87, -0.41, P = 0.766) showed that BoNT therapy worked well especially in improving mental state and quality of life. Ptosis was considered as the most common adverse reaction during BoNT injections (OR: 0.30, 95% CI: 0.11, 0.81, P = 0.843).

CONCLUSION

BoNT injection showed validity and clinical safety in the treatment of HFS, particular for depression relief. Injections around the mouth were only effective for HFS cases with severe symptoms. A standardized strategy for BoNT injections in managing HFS, detailing parameters such as injection sites, doses, and frequencies, remained elusive. Additional RCTs are necessary to further elucidate the interplay between efficacy and these components.

Altered Brain Structure in Hemifacial Spasm Patients: A Multimodal Brain Structure Study

Objective

Hemifacial spasm (HFS) is a clinical neurosurgical disease, which brain structural alterations caused by HFS remain a topic of debate. We evaluated changes in brain microstructure associated with HFS and observed their relevance to clinical characteristics.

Methods

We enrolled 72 participants. T1-weighted structural and diffusion tensor images were collected from all participants using 3.0T magnetic resonance equipment. Voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) were used to identify changes in gray matter volume (GMV) and disruptions in white matter (WM) integrity. The severity of the spasms was graded using the Cohn scale.

Results

VBM analysis revealed that the GMV was significantly reduced in the left Thalamus and increased GMV in the right Cerebellum IV-V of the HFS group. TBSS analysis showed that FA in the left superior longitudinal fasciculus (SLF) of the HFS group was significantly increased. GMV in the thalamus showed a negative correlation with disease duration and Cohn grade, while FA in the left SLF had a positive correlation with both the disease duration and Cohn grade.

Conclusion

We identified regions with altered GMV in HFS patients. Additionally, we determined that FA in the left SLF might serve as a significant neural indicator of HFS.

Evaluation of the effect of botulinum toxin A on the physical and mental health of patients with hemifacial spasm

BACKGROUND

Hemifacial spasm (HFS) is a debilitating disease characterized by involuntary tonic and clonic contractions of muscles innervated by the facial nerve. Botulinum toxin A (BTX-A) is the first-line option and the most effective medical treatment for HFS. The objective of this study was to evaluate the effect of BTX-A therapy on the physical and mental health of HFS patients.

METHODS

Participants included 65 HFS patients and 65 matched healthy controls in the study. Cornell Medical Index (CMI) self-assessment questionnaire was used to detect the psychological health of all participants. Local injection of BTX-A was applied, and the Cohen hierarchical criteria were employed to stratify the degree of spasticity, further evaluating the efficacy of BTX-A before and two months after treatment in HFS patients. The HFS patients at two months post-treatment were re-evaluated by CMI self-assessment questionnaire, and the evaluated factors of these patients were compared with those of patients before treatment.

RESULTS

The scores of somatization, depression, anxiety, inadaptation, sensitivity, anger, tension, M-R, and total scores in the HFS group were significantly higher than those in the control group (all P<0.05). Two months post-treatment, among 65 HFS patients who received with BTX-A treatment, 42 (64.6%) were completely relieved, 16 (24.6%) were significantly relieved, 7 (10.8%) were partially relieved, and 0 (0%) cases were invalid, and the total effective rate was 89.2%. Two months after BTX-A treatment, the scores of somatization, tension, anxiety, depression, sensitivity, M-R and total scores of patients with HFS were lower than those before treatment (all P<0.05).

CONCLUSIONS

Patients with HFS are often accompanied by somatization, anger, inadaptation, sensitivity, anxiety, depression, and tension. BTX-A can not only alleviate the symptoms of HFS, but also improve the somatization, tension, anxiety, depression, and sensitivity.

Cortical changes in the brain of patients with hemifacial spasm

OBJECTIVE

Hemifacial spasm (HFS) is a movement disorder characterized by involuntary muscle contractions on one side of the face. It is associated with disturbances in the brain's functional architecture. Despite this, the structural alterations in the brain related to HFS remain poorly understood. In this study, we investigated the cortical morphology changes in patients with HFS compared to healthy controls (HCs).

METHODS

We analyzed 3D T1-weighted MRI images from 33 patients with left-sided primary HFS and 33 age- and sex-matched HCs. Measurements of cortical thickness (CTh), sulcal depth, local gyrification index (lGI), and fractal dimension were taken using a computational anatomy toolbox. A general linear model, accounting for age, gender, and total brain volume, was applied for statistical analyses. Significant clusters were then assessed for correlations with clinical parameters.

RESULTS

The HFS patients displayed several cortical abnormalities when compared to HCs, including reduced CTh in the contralateral precentral gyrus and left orbitofrontal cortex, decreased sulcal depth in the left orbitofrontal cortex, and increased lGI in the right insula and superior temporal cortex. However, fractal dimension did not differ significantly between the groups. Additionally, in HFS patients, a notable negative correlation was found between the sulcal depth in the left orbitofrontal cortex and the Beck Depression Inventory-II scores.

CONCLUSIONS

Our findings reveal that HFS is associated with specific surface-based morphological changes in the brain. These alterations contribute to a deeper understanding of the neurophysiological mechanisms involved in HFS and may have implications for future research and treatment strategies.

White matter structural changes before and after microvascular decompression for hemifacial spasm

Hemifacial spasm (HFS) is a syndrome characterized by involuntary contractions of the facial muscles innervated by the ipsilateral facial nerve. Currently, microvascular decompression (MVD) is an effective treatment for HFS. Diffusion weighted imaging (DWI) is a non-invasive advanced magnetic resonance technique that allows us to reconstruct white matter (WM) virtually based on water diffusion direction. This enables us to model the human brain as a complex network using graph theory. In our study, we recruited 32 patients with HFS and 32 healthy controls to analyze and compare the topological organization of whole-brain white matter networks between the groups. We also explored the potential relationships between altered topological properties and clinical outcomes. Compared to the HC group, the white matter network was disrupted in both preoperative and postoperative groups of HFS patients, mainly located in the somatomotor network, limbic network, and default network (All P < 0.05, FDR corrected). There was no significant difference between the preoperative and postoperative groups (P > 0.05, FDR corrected). There was a correlation between the altered topological properties and clinical outcomes in the postoperative group of patients (All P < 0.05, FDR corrected). Our findings indicate that in HFS, the white matter structural network was disrupted before and after MVD, and that these alterations in the postoperative group were correlated with the clinical outcomes. White matter alteration here described may subserve as potential biomarkers for HFS and may help us identify patients with HFS who can benefit from MVD and thus can help us make a proper surgical patient selection.

Mapping trends in hemifacial spasm research: bibliometric and visualization-based analyses of the Web of Science Core Collection

Hemifacial spasm (HFS) is a common cranial nerve disease. In HFS research, we conducted a bibliometric analysis to examine the development and research trends. A retrieval of HFS studies published between 2011 and 2022 was performed from the Web of Science Core Collection in September 2022. Two scientometric tools were used to perform bibliometric and visualization-based analyses: VOSviewer and CiteSpace. Bibliometric analysis of 1461 studies published between 2011 and 2022 was carried out using data from 444 journals, 6021 authors, 1732 institutions, and 76 countries/regions. China, the USA, Japan, and South Korea were four key contributors to this study. Shanghai Jiaotong University was the major institution with the larger number of publications. Li Shiting was the most prolific author. Jannetta PJ was the most co-cited author. World Neurosurgery was the top prolific journal. Journal of Neurosurgery was the top co-cited journal. The top five keywords were hemifacial spasm, microvascular decompression, trigeminal neuralgia, surgery, and neurovascular compression. This study examines the research trends in global scientific research on HFS over the last decade. Researchers interested in learning more about current trends and novel research frontiers in this area can benefit from the study.

Brain White Matter Structural Alteration in Hemifacial Spasm: A Diffusion Tensor Imaging Study

OBJECTIVE

To analyze the changes in the white matter structure of the whole brain in hemifacial spasm (HFS) patients by using the tract-based spatial statistics (TBSS) method.

MATERIALS AND METHODS

29 HFS patients without anxiety and depression and 29 healthy controls with matching age, sex, and education were selected. All subjects received a 3.0T magnetic resonance (MR) brain diffusion tensor imaging scan. Tract-based spatial statistics method was used to analyze the changes in white matter structure in the whole brain and obtained the cerebral white matter fibrous areas exhibiting significant intergroup differences. The fractional anisotropy (FA), mean diffusivity, axial diffusivity, and radial diffusivity of these areas were abstracted. Analyzed the correlation between these diffusion metrics and clinical variables (disease duration, spasm severity).

RESULTS

Compared with the healthy controls group, the HFS group exhibited significantly lower FA in the forceps minor, bilateral anterior thalamic radiation, and right superior longitudinal fasciculus ( P <0.05, threshold-free cluster enhancement corrected). Cohen grading scale of HFS patients was negatively correlated with FA of forceps minor.

CONCLUSION

Based on TBSS analysis, the injury of white matter fiber tracts in HFS patients was found, including forceps minor, bilateral anterior thalamic radiation, and right superior longitudinal fasciculus. The changes of FA values in forceps minor were negatively correlated with the Cohen grading scale, suggesting that the alteration of white matter fiber in the genu-of-corpus-callosum-cortex circuit plays an important role in the neuro-pathological mechanism of HFS. Combined with previous research, it is also necessary to further explore the change of the superior longitudinal fasciculus in the future.

Alterations of white matter tracts and topological properties of structural networks in hemifacial spasm

Hemifacial spasm (HFS) is characterized by involuntary and paroxysmal muscle contractions on the hemiface. It is generally believed that HFS is caused by neurovascular compression at the root exit zone of the facial nerve. In recent years, the structural alterations of brains with HFS have aroused growing concern. However, little attention has been directed towards the possible involvement of specific white matter (WM) tracts and the topological properties of structural networks in HFS. In the present study, diffusion magnetic resonance imaging tractography was utilized to construct structural networks and perform tractometric analysis. The diffusion tensor imaging scalar parameters along with the WM tracts, and the topological parameters of global networks and subnetworks, were assessed in 62 HFS patients and 57 demographically matched healthy controls (HCs). Moreover, we investigated the correlation of these parameters with disease-clinical-level (DCL) and disease-duration-time (DDT) of HFS patients. Compared with HCs, HFS patients had additional hub regions including the amygdala, ventromedial putamen, lateral occipital cortex, and rostral cuneus gyrus. Furthermore, HFS patients showed significant alternations with specific topological properties in some structural subnetworks, including the limbic, default mode, dorsal attention, somato-motor, and control networks, as well as diffusion properties in some WM tracts, including the superior longitudinal fasciculus, cingulum bundle, thalamo-frontal, and corpus callosum. These subnetworks and tracts were associated with the regulation of emotion, motor function, vision, and attention. Notably, we also found that the parameters with subnetworks and tracts exhibited correlations with DCL and DDT. In addition to corroborating previous findings in HFS, this study demonstrates the changed microstructures in specific locations along with the fiber tracts and changed topological properties in structural subnetworks.

Altered Cortical-Striatal Network in Patients With Hemifacial Spasm

Objective: Hemifacial spasm (HFS) is a kind of motor disorder, and the striatum plays a significant role in motor function. The purpose of this study was to explore the alterations of the cortical-striatal network in HFS using resting-state functional magnetic resonance imaging (fMRI). Methods: The fMRI data of 30 adult patients with primary unilateral HFS (15 left-side and 15 right-side) and 30 healthy controls were collected. Six subregions of the striatum in each hemisphere were selected for functional connectivity (FC) analysis. One-sample t-test was used to analyze the intragroup FC of the HFS group and the control group. Two-sample t-test was used to compare the difference of FC between the two groups. The correlation between the abnormal FC and severity of HFS was evaluated by using the Spearman correlation analysis. Results: Compared with the controls, the striatal subregions had altered FC with motor and orbitofrontal cortex in patients with HFS. The altered FC between striatal subregions and motor cortex was correlated with the spasm severity in patients with HFS. Conclusion: The FC of the cortical-striatal network was altered in primary HFS, and these alterations were correlated with the severity of HFS. This study indicated that the cortical-striatal network may play different roles in the underlying pathological mechanism of HFS.

Abnormal Regional Spontaneous Brain Activity and Its Indirect Effect on Spasm Ratings in Patients With Hemifacial Spasm

PURPOSE

Three classical methods of resting-state functional magnetic resonance imaging (rs-fMRI) were employed to explore the local functional abnormalities and their effect on spasm ratings in hemifacial spasm (HFS) patients.

METHODS

Thirty HFS patients and 30 matched healthy controls (HCs) were recruited. Rs-fMRI data, neurovascular compression (NVC) degree and spasm severity were collected in each subject. Fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and degree centrality (DC) were calculated in the whole brain voxels. Two sample t-tests were performed to investigate group differences of fALFF, ReHo, and DC. Correlation analysis was performed to assess the relationships between the regional brain abnormalities and clinical variables in HFS.

RESULTS

Compared with HCs, HFS patients exhibited increased fALFF in the left precuneus and right posterior cingulate cortex (PCC), together with increased ReHo in the bilateral PCC and bilateral precuneus. Decreased ReHo was observed in the right middle occipital gyrus (MOG), right superior occipital gyrus (SOG), right cuneus, and right angular gyrus (AG) in HFS patients. Moreover, ReHo in the right PCC were positively correlated with NVC degree and spasm severity in HFS patients, respectively. Mediation analysis revealed that increased ReHo in the right PCC regulated the neurovascular compression degree, and further resulted in increased spasm ratings.

CONCLUSION

Our study revealed regional brain dysfunctions from different perspectives and an indirect effect of ReHo in right PCC on spasm ratings predominantly through the alteration of NVC.

[Hemifacial spasm]

Hemifacial spasm (HFS), or facial hemispasm, is a paroxysmal hyperkinetic disorder involving muscles innervated by the facial nerve, mainly on the one hand. The development of HFS is based on neurovascular conflict. However, it is impossible to explain the clinical manifestations of HFS only by nerve compression. Both peripheral and central mechanisms are involved in the generation of HFS, with the formation of ephaptic transmission, antidromic excitation, primary or secondary hyper-excitability of the nuclear and supranuclear level of innervation. Two treatment methods are pathogenetically justified: microvascular decompression (MVD) and botulinum toxin (BTX) injections. The effectiveness of MVD is 95.37% with full or partial recovery. The recurrence rate does not exceed 2.4%. Facial nerve paralysis (2.7-22.5%) and hearing loss (1.9-20%) are the most common complications of treatment with the use of the MVD for HFS with partial or complete cure in most cases. Botulinum toxin injection chemo-denervation is a first-line treatment of primary and secondary HFS. HFS is an officially registered indication for the drug dysport (abobotulotoxin) (ABO) in the Russian Federation. Total doses of ABO ranged from 25 to 150 units for one side depending on the severity of the clinical manifestations. Studies demonstrate the statistically significant benefits of HFC treatment with ABO. ABO is generally well-tolerated. Adverse events (up to 3.6%) are transient and include ptosis, lacrimation, blurred vision, double vision, dry eyes and weak facial muscles.

Strengthened thalamoparietal functional connectivity in patients with hemifacial spasm: a cross-sectional resting-state fMRI study

OBJECTIVE

In spite of the well-known importance of thalamus in hemifacial spasm (HFS), the thalamic resting-state networks in HFS is still rarely mentioned. This study aimed to investigate resting-state functional connectivity (FC) of the thalamus in HFS patients and examine its association with clinical measures.

METHODS

25 HFS patients and 28 matched healthy controls underwent functional MRI at rest. Using the left and right thalamus as seed regions respectively, we compared the thalamic resting-state networks between patient and control groups using two independent sample t-test.

RESULTS

Compared with controls, HFS patients exhibited strengthened bilateral thalamus-seeded FC with the parietal cortex. Enhanced FC between right thalamus and left somatosensory association cortex was linked to worse motor disturbance, and the increased right thalamus-right supramarginal gyrus connection were correlated with improvement of affective symptoms.

CONCLUSION

Our findings indicate that the right thalamus-left somatosensory association cortex hyperconnectivity may represent the underlying neuroplasticity related to sensorimotor dysfunction. In addition, the upregulated FC between the right thalamus and right supramarginal gyrus in HFS, is part of the thalamo-default mode network pathway involved in emotional adaptation.

ADVANCES IN KNOWLEDGE

This study provides new insights on the integrative role of thalamo-parietal connectivity, which participates in differential neural circuitry as a mechanism underlying motor and emotional functions in HFS patients.

Subcortical Brain Abnormalities and Clinical Relevance in Patients With Hemifacial Spasm

Purpose: Hemifacial spasm (HFS), a rare neuromuscular movement disorder, is characterized by unilateral, irregular, and paroxysmal facial muscle contractions. To explore the central neural mechanisms of HFS, we conducted vertex-wise shape analyses to investigate volume and shape alterations of subcortical structures, which could help to better understand the abnormality in distinct subcortical regions and determine alternative biomarkers of HFS.

Methods: Thirty patients with HFS and 30 age- and sex-matched healthy controls provided written informed consent. T1-weighted structural magnetic resonance imaging (MRI) data were collected from all participants. Vertex-wise shape analyses were performed to assess the volume and shape alterations of subcortical structures following HFS. Post hoc correlations with spasm severity and measures of mood dysfunction were applied to characterize subcortical brain alterations.

Results: Compared with healthy controls, patients with HFS showed increased volume in the right caudate specifically. Furthermore, patients exhibited significant shape atrophy in the anterior medial aspect of left pallidum, together with shape expansion in the anterior ventrolateral aspect of right caudate head. In addition, shape alteration in right caudate was positively correlated with both anxiety and depression severity in patients with HFS.

Conclusions: This is the first study to employ vertex-wise shape analysis to investigate subcortical brain abnormalities in patients with HFS. Our findings provide compelling evidence for subcortical brain alterations specific to HFS, and further may shed light on the pathophysiology of HFS and apply to the translational medicine.

Structural and Functional Amygdala Abnormalities in Hemifacial Spasm

Background and Purpose: Hemifacial spasm (HFS) is a rare neuromuscular disorder characterized by unilateral, involuntary, and paroxysmal contractions of orofacial muscles. To elucidate the central neural mechanisms of HFS, we investigated brain gray matter and resting-state functional connectivity (rsFC) in HFS patients. Methods: Thirty patients with HFS and 30 age- and sex-matched healthy participants consented to the study. T1-weighted structural magnetic resonance imaging (MRI) and resting-state BOLD images were collected in all participants. Cortical gray matter thickness was assessed, and subcortical volumetric analysis was performed. Seed-based rsFC analysis was performed on structurally abnormal regions in HFS patients. Post hoc correlations with HFS severity and measures of mood (i.e., depression and anxiety) were performed to characterize rsFC alterations. Results: There were no significant differences in cortical thickness in HFS patients compared to healthy controls. Patients with HFS presented smaller right amygdala volume in contrast to healthy controls (q < 0.05, false-discovery rate corrected). We found that the right amygdala had increased rsFC with bilateral medial prefrontal cortex (mPFC), bilateral orbital frontal cortex (OFC), and left posterior insula (L postIns; voxel-wise p < 0.05, family-wise error corrected). Moreover, the connections of amygdala-postIns and amygdala-mPFC were positively related to HFS severity and anxiety, respectively. Conclusions: This is the first study to show structural and functional brain abnormalities in HFS. The volumetric and rsFC amygdala abnormalities were potentially driven by HFS, providing novel insights into HFS pathophysiology.

Evaluation of stigmatization in hemifacial spasm and quality of life before and after botulinum toxin treatment

Hemifacial spasm (HFS) is a chronic disease that is characterized by involuntary tonic and clonic contractions of the muscles innervated by the ipsilateral facial nerve. Botulinum toxin (BTX) is the most effective medical treatment of this condition. The aim of our study was to evaluate stigma among patients diagnosed with HFS and to search quality of life and depression before and after BTX injection. Seven self-rating items (HFS-7) and seven questions related to stigmatization were administered to HFS patients. Participants also answered SF-36 health outcome measure and Beck depression inventory before and 4 weeks after the routine BTX injection. The severity of HFS was graded based on a five-point scale. Descriptive statistics and paired t test were applied. The level of significance was set at α = 0.05. Fourty HFS patients were prospectively included. Twenty-one (%52.5) were female and nineteen were male (47.5%) with a mean age of 57.1 (SD = 12.13; min-max = 27-78). 60% (n: 24) of patients were feeling themselves different from people without HFS. Beck depression inventory scores improved after BTX injection significantly (p < 0.05). All domains of SF-36 showed positive improvement after BTX injections. The improvement in general health perception, physical functioning, and vitality was statistically significant (p < 0.05). Although more than half of the patients felt themselves different from people without HFS, treatment of HFS with BTX significantly improved mental health and physical health, and depressive symptoms of the patients.

Persistent hemifacial spasm after microvascular decompression: a risk assessment model

OBJECTIVE

Microvascular decompression (MVD) for hemifacial spasm (HFS) provides resolution of disabling symptoms such as eyelid twitching and muscle contractions of the entire hemiface. The primary aim of this study was to evaluate the predictive value of patient demographics and spasm characteristics on long-term outcomes, with or without intraoperative lateral spread response (LSR) as an additional variable in a risk assessment model.

METHODS

A retrospective study was undertaken to evaluate the associations of pre-operative patient characteristics, as well as intraoperative LSR and need for a staged procedure on the presence of persistent or recurrent HFS at the time of hospital discharge and at follow-up. A risk assessment model was constructed with the inclusion of six clinically or statistically significant variables from the univariate analyses. A receiving operator characteristic curve was generated, and area under the curve was calculated to determine the strength of the predictive model.

RESULTS

A risk assessment model was first created consisting of significant pre-operative variables (Model 1) (age >50, female gender, history of botulinum toxin use, platysma muscle involvement). This model demonstrated borderline predictive value for persistent spasm at discharge (AUC .60; p=.045) and fair predictive value at follow-up (AUC .75; p=.001). Intraoperative variables (e.g. LSR persistence) demonstrated little additive value (Model 2) (AUC .67). Patients with a higher risk score (three or greater) demonstrated greater odds of persistent HFS at the time of discharge (OR 1.5 [95%CI 1.16-1.97]; p=.035), as well as greater odds of persistent or recurrent spasm at the time of follow-up (OR 3.0 [95%CI 1.52-5.95]; p=.002) Conclusions: A risk assessment model consisting of pre-operative clinical characteristics is useful in prognosticating HFS persistence at follow-up.