Surgical treatment of hemifacial spasm caused by fusiform vertebral artery aneurysm: case report and literature review.

BACKGROUND: Root exit zone (REZ) compression by a fusiform vertebral artery (VA) aneurysm is a rare cause of hemifacial spasm (HFS). We report a case of successful microvascular decompression (MVD) for the treatment of HFS caused by a fusiform VA aneurysm. We also review the relevant literature and demonstrate the effectiveness of surgical treatment. CASE DESCRIPTION: A 64-year-old man presented with a 2-year and 4-month history of progressive involuntary facial twitching on the right side. Radiological examination revealed a fusiform right VA aneurysm. The REZ that was compressed by the aneurysm and the underlying anterior inferior cerebellar artery (AICA) was surgically decompressed by transposing the VA and AICA and wrapping the aneurysm. Immediately post-operation, the patient's symptoms disappeared. For 7 years and 4 months postoperatively, there was no symptom recurrence or increase in aneurysm size. CONCLUSION: MVD is an effective treatment for HFS caused by a fusiform VA aneurysm because symptoms are likely to improve immediately after treatment.

[How to Clip Cerebral Aneurysms Safely and Reliably?]

For safe and reliable cerebral aneurysm clipping, First of all, clean bloodless surgical field and stable and fine movements of micro scissors are necessary. The surgeon must use both hands and determine the best angle before retracting the brain. One of the most basic and important things is that the tips of the clip should be kept continuously in sight until closing clips. We propose a "blading technique" for visualizing the tips of clip blades using a 3-dimensional applier clip manipulation, maintaining contact with the aneurysm while maintaining complementary movement of the suction device in the opposite hand. Before trying to detach the adhering vessels from the aneurysm, the surgeon should consider necessity. Clipping is frequently accomplished using various manipulation techniques with remaining adhesions. This article presents basic clipping and manipulation techniques.

Low entropy of interictal gamma oscillations is a biomarker of the seizure onset zone in focal cortical dysplasia type II.

OBJECTIVE: Dynamic changes in the regularity of interictal gamma oscillations (GOs, 30-70 Hz) on intracranial electroencephalography (EEG) reflect focal ictogenesis with epileptogenic neuronal synchronization in focal cortical dysplasia (FCD). We investigated whether the regularity of interictal GOs is a biomarker of the seizure onset zone (SOZ) using multiscale entropy analysis. METHODS: We quantified the regularity of interictal GOs using intracranial EEG data from 1164 electrodes in 13 patients with FCD who were seizure-free postoperatively. The regularity of interictal GOs was quantified as entropy values. Low entropy represents high regularity. We standardized entropy values using Z values for each SOZ, resection area (RA), and the region outside the RA. The cutoff Z values, sensitivity, and specificity for detecting each area were calculated using area under the receiver operating characteristics curves (AUCs). RESULTS: Low Z values represent higher regularity of GOs. The cutoff Z value of ≤-2.09 for the SOZ had a sensitivity of 100% and specificity of 97.1% (AUC = 0.992 ±â€¯0.002). The cutoff Z value of ≤-0.12 for the RA had a sensitivity of 54.2% and specificity of 73.8% (AUC = 0.673 ±â€¯0.019). The cutoff Z value of ≥-0.11 for the region outside the RA had a sensitivity of 73.8% and specificity of 54.2% (AUC = 0.673 ±â€¯0.019). CONCLUSIONS: Low entropy of interictal GOs was a reliable biomarker for the SOZ. Maintained high entropy of interictal GOs may be an auxiliary biomarker for nonepileptogenic regions. SIGNIFICANCE: Low entropy of interictal GOs may be a biomarker for the SOZ in FCD type II.

Is surgical parent artery occlusion effective for intracranial aneurysms measuring over 10 mm in size? Result from long-term follow-up of size changes and outcomes.

BACKGROUND: There have been no long-term follow-up reports pertaining to chronological size changes in large or giant unruptured intracranial aneurysms treated with surgical parent artery occlusion (PAO). The object of this study is to investigate the utility and safety of surgical PAO by conducting a long-term follow-up of chronological aneurysm size changes and outcomes. METHODS: A retrospective study of 21 unruptured intracranial aneurysms measuring over 10 mm (20 patients) treated with surgical PAO in the period 2012-2017 was conducted. For aneurysms presenting with anterior circulation, high/low flow bypass was chosen and carried out concomitantly on the basis of preoperative balloon occlusion test results. Aneurysm size before and after surgery was evaluated chronologically using maximum diameter measurements taken from the same slice of MRI T2-weighted images. Moreover, post-surgery outcomes were evaluated according to a modified Rankin scale (mRS) at discharge. RESULTS: PAO aiming for blind-alley formation was performed in 20 of 21 aneurysms (95.2%). Aneurysm size reduction was confirmed in 20 aneurysms (95.2%) after proper PAO, with an average reduction rate of 63.1% (range, 28-95%), during an average follow-up period of 27 months (range, 4-54 months). Eighteen (90.4%) of the 20 patients with 21 aneurysms returned to previous life with mRS score 0-2. With regard to preoperative symptoms, diplopia and visual impairment had improved in three patients (50%) and one patient (100%), respectively. Ischemic complications had occurred in five patients, two (9.6%) of whom were symptomatic and three (14.3%) were asymptomatic. The mortality rate in this study was 0%. CONCLUSIONS: Surgical PAO for unruptured intracranial aneurysms measuring over 10 mm has been shown to be an effective method of treatment, eliciting a reduction in aneurysm size.

Gene expression profiling reveals distinct molecular signatures associated with the rupture of intracranial aneurysm.

BACKGROUND AND PURPOSE: The rupture of intracranial aneurysm (IA) causes subarachnoid hemorrhage associated with high morbidity and mortality. We compared gene expression profiles in aneurysmal domes between unruptured IAs and ruptured IAs (RIAs) to elucidate biological mechanisms predisposing to the rupture of IA. METHODS: We determined gene expression levels of 8 RIAs, 5 unruptured IAs, and 10 superficial temporal arteries with the Agilent microarrays. To explore biological heterogeneity of IAs, we classified the samples into subgroups showing similar gene expression patterns, using clustering methods. RESULTS: The clustering analysis identified 4 groups: superficial temporal arteries and unruptured IAs were aggregated into their own clusters, whereas RIAs segregated into 2 distinct subgroups (early and late RIAs). Comparing gene expression levels between early RIAs and unruptured IAs, we identified 430 upregulated and 617 downregulated genes in early RIAs. The upregulated genes were associated with inflammatory and immune responses and phagocytosis including S100/calgranulin genes (S100A8, S100A9, and S100A12). The downregulated genes suggest mechanical weakness of aneurysm walls. The expressions of Krüppel-like family of transcription factors (KLF2, KLF12, and KLF15), which were anti-inflammatory regulators, and CDKN2A, which was located on chromosome 9p21 that was the most consistently replicated locus in genome-wide association studies of IA, were also downregulated. CONCLUSIONS: We demonstrate that gene expression patterns of RIAs were different according to the age of patients. The results suggest that macrophage-mediated inflammation is a key biological pathway for IA rupture. The identified genes can be good candidates for molecular markers of rupture-prone IAs and therapeutic targets.

Spontaneous regression of restenosis after CEA: significance of preoperative plaque characteristics under duplex ultrasound; clinical investigation.

BACKGROUND: Restenosis is a postoperative complication after carotid endarterectomy (CEA). The natural clinical course of restenotic lesions is not yet fully understood. This study was aimed at detecting the pattern of restenotic lesions by way of following the plaque thickness under duplex ultrasound, and the possible relationship between the postoperative changes of restenotic lesions and the preoperative plaque characteristics. METHOD: Serial duplex ultrasound follow-up studies were conducted postoperatively, and intima-media thickness (IMT) was measured to detect restenosis changes. Among 381 cases of CEA, including 25 cases of restenosis, 11 were eligible for further analysis. FINDINGS: Of the 11 cases of restenosis, four showed a gradual increase in IMT, and five showed a temporary increase followed by a decrease in IMT. All cases in the former group showed isoechogenic or hypoechogenic plaques under preoperative duplex ultrasound. In contrast, all cases in the latter group demonstrated calcified plaques together with acoustic shadows. CONCLUSIONS: These postoperative chronological IMT data demonstrate two changing patterns of restenosis, implying the existence of two distinct entities. In addition, these results suggest that restenosis after removal of a calcified plaque, which supposedly forms secondary to myointimal hyperplasia, may be a temporary phenomenon that acutely develops in response to a dissection maneuver during surgery. Because our speculation is based on a small number of cases, further study is warranted to better understand the pathophysiology of restenosis regression.

A unique and effective bypass technique to treat partially thrombosed giant distal anterior cerebral artery aneurysms in extremely narrow surgical corridors.

BACKGROUND: Surgical treatment of large or giant thrombosed anterior cerebral artery (ACA) aneurysms often involves revascularization. Herein, we describe a unique and effective bypass technique to treat partially thrombosed giant distal ACA aneurysms in extremely narrow surgical corridors. METHODS: A 68-year-old man underwent aneurysm trapping and ACA revascularization for a partially thrombosed giant ACA aneurysm in a surgical corridor that was narrow due to anatomic factors. By combining a side-to-side anastomosis and an end-to-side anastomosis at a single anastomotic site, we successfully redirected blood flow from the left pericallosal artery to the right pericallosal and callosomarginal arteries. RESULTS: Postoperatively, cerebral angiography showed that the blood flow in the aneurysm had disappeared, and the bypass remained open. The patient's functional disability gradually improved, and he reported consistently positive outcomes at the 6-month postoperative follow-up examination. CONCLUSION: This revascularization technique may represent an effective novel treatment option, particularly when multiple revascularization procedures are required within a narrow surgical field.

Metagenomic Analysis of Bacterial Microflora in Dental and Atherosclerotic Plaques of Patients With Internal Carotid Artery Stenosis.

Background: Internal carotid artery stenosis is primarily attributed to atherosclerosis in the carotid artery bifurcation. Previous studies have detected oral bacteria in atherosclerotic lesions, suggesting an association between oral bacteria and atherosclerosis. In this study, we compared the bacterial flora of the atherosclerotic plaque in the carotid artery and dental plaque of patients with internal carotid artery stenosis using 16S ribosomal RNA (16S rRNA) metagenomic sequencing. Methods: Fifty-four patients who underwent internal carotid endarterectomy for internal carotid artery stenosis at the Showa University Hospital between April 2016 and February 2018 were included. Polymerase chain reaction targeting the 16S rRNA gene detected bacterial DNA in the carotid plaques of 11 cases, of which only 5 could be further analyzed. Thereafter, DNA extracted from the carotid and oral plaques of these 5 cases were analyzed using metagenomic sequencing targeting 16S rRNA. In addition, their general condition and oral conditions were evaluated. The patients were classified into symptomatic and asymptomatic groups based on the presence or absence of symptoms of transient ischemic attack, and their bacterial flora was evaluated. Results: The results demonstrated that the microflora of carotid plaques (n = 5) contained bacterial species from 55 families and 78 genera. In addition, 86.5% of the bacteria detected in the carotid plaques were also detected in oral plaques. Cariogenic and periodontopathic bacteria accounted for 27.7% and 4.7% of the bacteria in the carotid plaques, respectively. Conclusions: These results suggest that oral bacteria are directly or indirectly involved in the pathogenesis of atherosclerosis. More extensive studies of oral commensal bacteria detected in extra-oral lesions are warranted to comprehensively investigate the role of oral bacteria in the pathogenesis of systemic diseases.

Microscopic anterior clinoidectomy with micro-rongeurs for a superior projecting paraclinoid internal carotid artery aneurysm: a technical note.

Anterior clinoidectomy is an essential manoeuvre for clipping paraclinoid internal carotid artery (ICA) aneurysms. However, the use of a drill or an ultrasonic bone curette in an anterior clinoidectomy involves a high risk for heat or mechanical injury of the superior projecting paraclinoid aneurysm. We report our technique for microscopic anterior clinoidectomy performed only using a micro-rongeur. The case of a superior projecting paraclinoid ICA aneurysm is presented. The anterior clinoid process was removed with our specially crafted micro-rongeurs, while we observed the extradural and intradural routes under a microscope. The aneurysm was completely clipped without any resulting neurological deficits. This technique can be safely used for paraclinoid ICA aneurysms, especially for superiorly projecting aneurysms.

Surgical treatment for extremely rare solitary fibrous tumors of the central nervous system originating from cranial nerve VIII: new clinicopathological findings. Illustrative case.

BACKGROUND: Reports of solitary fibrous tumors (SFTs) of the central nervous system (CNS) originating from cranial nerves are extremely rare. The origins of these neurogenic SFTs of the CNS have been determined only by intraoperative findings, and there is no pathological evidence of whether they really originated from cranial nerves. OBSERVATIONS: A 54-year-old female with hearing loss and facial paralysis presented with a giant right cerebellopontine angle tumor. She was diagnosed with a petrous meningioma based on preoperative imaging, and the tumor was removed via the retrosigmoid approach after embolization of the tumor-feeding vessels. Intraoperatively, the tumor was not attached to the dura mater but extended from the internal auditory canal to the cisternal portion. The acoustic nerve was not identified, but it was possible to separate the tumor from the facial nerve. The tumor was removed as an acoustic schwannoma intraoperatively. Postoperative pathological examination revealed an SFT. Immunostaining revealed peripheral nerve bundles entrapped within the tumor tissue. The patient was diagnosed with an SFT of the CNS originating from the acoustic nerve. LESSONS: A neurogenic SFT of the CNS was diagnosed based on both intraoperative and pathological findings.

Single-Center Case Series of Simple Proximal Clipping for Large Thrombosed Vertebral Artery Aneurysms: Preservation of Perforating Arteries and Long-Term Outcomes.

BACKGROUND: Surgical proximal parent artery occlusion (PAO) is one of the treatments for partially thrombosed vertebral artery aneurysms (PTVAs). However, whether long-term changes in size and perforating arteries through the blind end can be truly preserved remain unknown. OBJECTIVE: To evaluate the efficacy and safety of surgical proximal PAO for PTVAs, focusing on the transition in size and preservation of perforating arteries. METHODS: We retrospectively reviewed 14 consecutive cases of unruptured large PTVAs. The cases were treated with surgical proximal PAO without trapping or thrombectomy. Preservation of the perforating arteries was confirmed through intraoperative indocyanine green video angiography. The aneurysm size was evaluated by measuring the maximum diameter on axial T2-weighted magnetic resonance images. Post-treatment outcomes were assessed using the modified Rankin Scale at the last follow-up examination. RESULTS: Thirteen patients (excluding 1 with morbidity) had a mean follow-up time of 33.2 months (range, 12-60 months) and a mean reduction rate of 71% (range, 32%-95%). Only 1 patient (7.2%) experienced postoperative stroke, and 13 patients (92.8%) showed no worsening of the modified Rankin Scale score at the final follow-up examination. The symptoms were improved in 5 of the 6 symptomatic patients (83.3%). In 10 patients (71.4%), a perforating branch that could not be identified on preoperative imaging was identified intraoperatively. CONCLUSION: Surgical proximal PAO without trapping or thrombectomy for PTVAs allows long-term reduction of aneurysm size and improves treatment safety by preserving the perforating artery, especially in cases wherein direct reconstruction is not feasible.

Stent-Assisted Coil Embolization of Ruptured Aneurysms in the Acute Stage: Advantages and Disadvantages.

Objective: In the acute stage of ruptured cerebral aneurysms, limited devices are available, making the treatment difficult. We aimed to evaluate the outcomes of the coil embolization with stenting for the ruptured cerebral aneurysms in the acute stage. Methods: We assessed 22 cases treated with stenting among 134 of 169 consecutive patients with subarachnoid hemorrhages undergoing an endovascular treatment between April 2014 and December 2021, of which 134 underwent an embolization during the acute stage. A stent was used in the patients wherein the treatment with the balloon-assisted or double catheter technique was difficult. Stenting was performed under the loading of two or more antiplatelet agents. Results: The mean age of the patients was 68.9 years, of which five were male and 14 (63.6%) had severe grade (World Federation of Neurosurgeons grade IV, V). The aneurysm site was the anterior communicating artery in four cases, internal carotid artery in nine, middle cerebral artery in two, vertebrobasilar artery in six, and posterior cerebral artery in one. The aneurysm shape was saccular in 13 cases, dissection in seven, and fusiform in two. Stents were used for wide-neck aneurysms in 12 cases, vascular preservation in seven, and rescue in three. The mean maximum diameter was 9.6 mm. The mean neck size was 6.4 mm. Complete occlusion and neck remnant were found in eight and seven cases, respectively. The perioperative complication rate was 45.5% (thromboembolism in five cases, stent occlusion in two, re-bleeding in two, and cerebral hemorrhage in one). The outcomes included modified Rankin Scale 0-2 in seven cases, 4-5 in five, and 6 in nine. Stent-related death occurred in one case. The rate of morbidity and mortality was 18.2%. Although stents were used in the acute stage of rupture, they were used for the right reasons. However, a high rate of complications occurred: two cases of re-bleeding, in which an incomplete occlusion was a factor. Conclusion: Stent placement in patients with the acute ruptured cerebral aneurysms should be carefully determined and efforts should be made to reduce the embolic and hemorrhagic complications. However, it may be an effective treatment option when other options could be extremely difficult.

Carotid artery stenting for stenosis after carotid artery replacement: An illustrative case report.

Background: There are few reports on the treatment of carotid artery stenosis after arterial vessel replacement. We report and discuss an illustrative case of carotid artery stenting (CAS) performed for stenosis after carotid artery replacement. Case Description: A woman in her 20s experienced injury to the right carotid artery during an operation for removal of a carotid body tumor 6 years before presentation. The right common carotid artery and internal carotid artery were replaced with an artificial vessel graft at that time. Intraluminal stenosis in the graft was not identified 3 years after surgery; however, 4 years after surgery, stenosis was recognized at the non-anastomotic site inside the artificial vessel graft. Subsequently, antiplatelet therapy was initiated. The stenosis was noted to progress gradually in follow-up appointments. Therefore, we decided to intervene because of the patient's young age and the risk of long-term hemodynamic stress. Angiography revealed pseudo-occlusion in the artificial vessel. Percutaneous transluminal angioplasty was performed for stenosis with distal protection; subsequently, CAS was performed. The patient was discharged without neurological deficits 4 days after the operation, and no apparent restenosis was observed as of the 1-year follow-up. Conclusion: Stenosis after cervical artery replacement can be safely treated with CAS. Inflation pressure and stent should be selected according to the pathology of the stenosis.

Intracranial Non-Sinus-Type Dural Arteriovenous Fistulas Could Be Curable by Transarterial Embolization or Transvenous Embolization with Liquid Embolic Material.

Objective: Recently, the occlusion rate of transarterial embolization (TAE) for intracranial non-sinus-type dural arteriovenous fistulas (NSDAVFs) has improved after ONYX was introduced. Additionally, when TAE for NSDAVF is unsuccessful, transvenous embolization (TVE) has become available as an alternative treatment. We investigated the factor for the favorable occlusion rate of endovascular treatment for NSDAVF at our institutions. Methods: Two hundred and twenty-seven patients with intracranial dural arteriovenous fistulas (DAVFs) were treated at our institutions between September 2014 and October 2022. The patients diagnosed with NSDAVF in all DAVFs who underwent endovascular treatment were included. The clinical characteristics, angiographical outcomes, and clinical outcomes of patients who underwent endovascular treatment were evaluated. Results: Thirty-eight patients had intracranial NSDAVF (tentorial: 23 cases, parasagittal-convexity: 7, anterior cranial fossa: 6, middle cranial fossa: 2). Our participants' mean age was 64.8 ± 11.3 years, and 31 (81.6%) of them were males. Patients' symptoms were as follows: asymptomatic (24), hemorrhage (10), tinnitus (3), and trigeminal neuralgia (1). TAE and TVE were performed on 35 and 3 patients, respectively. The rate of immediate angiographical occlusion was 84.2% (32/38). The follow-up angiographical occlusion rate in 6 months was 88.5% (31/35). Complications occurred in three cases. There was no morbidity or mortality after 30 days. Conclusion: TAE using the combination of the new microcatheter and microguidewire and TVE in the case of difficult or failed TAE for NSDAVF could achieve high success rates and safety.

Detection of ophthalmic artery occlusion by visual evoked potential during carotid-ophthalmic artery aneurysm clipping.

We report an intriguing case of carotid-ophthalmic artery (OA) aneurysm surgery, in which the visual evoked potential (VEP) wave diminished during temporary OA occlusion. VEP waves suddenly disappeared after clipping, and repositioning of the clip restored blood flow to the OA and recovered the VEP wave.

Ruptured infectious aneurysms of the distal MCA treated with trapping and STA-MCA bypass surgery.

We describe two patients with ruptured infectious aneurysms of the distal MCA, which were successfully treated by trapping and superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery. Our patients had not experienced any ischemic attack postoperatively. Trapping and STA-MCA bypass surgery can be a useful option.

Interictal High Gamma Oscillation Regularity as a Marker for Presurgical Epileptogenic Zone Localization.

BACKGROUND: To ensure that epilepsy surgery is effective, accurate presurgical localization of the epileptogenic zone is essential. Our previous reports demonstrated that interictal high gamma oscillation (30-70 Hz) regularity (GOR) on intracranial electroencephalograms is related to epileptogenicity. OBJECTIVE: To examine whether preoperative GOR analysis with interictal high-density electroencephalography (HD-EEG) improves the accuracy of epileptogenic focus localization and enhances postoperative seizure control. METHODS: We calculated GOR from 20 seconds of HD-EEG data for 21 patients with refractory focal epilepsy (4 with nonlesional temporal lobe epilepsy) scheduled for epilepsy surgery. Low-resolution brain electromagnetic tomography was used to analyze the high GOR source. To validate our findings, we made comparisons with other conventional localization methods and postoperative seizure outcomes. RESULTS: In all patients, the areas of interictal high GOR were identified and resected. All patients were seizure-free after the operation. The concordance between the results of interictal high GOR on HD-EEG and those of source estimation of interictal discharge was fully overlapping in 10 cases, partially overlapping in 8 cases, and discordant in 3 cases. The concordance between the results of interictal high GOR on HD-EEG and those of interictal 123 I-iomazenil single-photon emission computed tomography was fully overlapping in 8 cases, partially overlapping in 11 cases, and discordant in 2 cases. In 4 patients with nonlesional temporal lobe epilepsy, the interictal high GOR on HD-EEG was useful in confirming the epileptogenic zone. CONCLUSION: The interictal high GOR on HD-EEG is an excellent marker for presurgical epileptogenic zone localization.

Visualization of ictal networks using gamma oscillation regularity correlation analysis in focal motor epilepsy: Illustrative cases.

Background: Focal motor epilepsy is difficult to localize within the epileptogenic zone because ictal activity quickly spreads to the motor cortex through ictal networks. We previously reported the usefulness of gamma oscillation (30-70 Hz) regularity (GOR) correlation analysis using interictal electrocorticographic (ECoG) data to depict epileptogenic networks. We conducted GOR correlation analysis using ictal ECoG data to visualize the ictal networks originating from the epileptogenic zone in two cases - a 26-year-old woman with negative motor seizures and a 53-year-old man with supplementary motor area (SMA) seizures. Case Description: In both cases, we captured several habitual seizures during monitoring after subdural electrode implantation and performed GOR correlation analysis using ictal ECoG data. A significantly high GOR suggestive of epileptogenicity was identified in the SMA ipsilateral to the lesions, which were connected to the motor cortex through supposed ictal networks. We resected the high GOR locations in the SMA and the patients' previously identified tumors were removed. The patients were seizure-free without any neurological deficits after surgery. Conclusion: The GOR correlation analysis using ictal ECoG data could be a powerful tool for visualizing ictal networks in focal motor epilepsy.

Factors Related to the Delayed Cure of Hemifacial Spasm after Microvascular Decompression: An Analysis of 175 Consecutive Patients.

Detailed studies assessing the factors related to delayed cure of hemifacial spasm (HFS) after microvascular decompression (MVD) are sparse. We aimed to evaluate the effect of 11 clinical factors on the time until the patient became spasm free after MVD. We enrolled 175 consecutive patients with HFS who underwent MVD between 2012 and 2018. The end point was defined as the time point at which the patient became spasm free based on the outpatient interview. Patients were divided into six groups depending on when they became spasm free after the operation, as follows: <7 days ( n = 62), 7 days to 1 month ( n = 28), 1 to 3 months ( n = 38), 3 to 6 months ( n = 25), 6 to 12 months ( n = 17), and >12 months ( n = 5). The median time to become spasm free after MVD was 30.0 days. Association of 11 factors (age, sex, laterality, number of offending arteries, vertebral artery compression, number of compression sites, compression at root detachment zone, preoperative Botox treatment, indentation of the brain stem on preoperative magnetic resonance image, transposition, and interposition) with spasm-free rate was assessed using the Cox's proportional hazards model. Spasm-free rate curve after MVD for the significant factor was obtained using the Kaplan-Meier method. In univariate and multivariate analyses, nontransposition was significantly related to delayed HFS cure after MVD (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.42, 0.87; p = 0.0068 and HR, 0.60; CI, 0.43, 0.85; p = 0.042, respectively). The spasm-free rate was higher in the transposition than in the nontransposition group ( p = 0.0013). As shortening the time until spasm free after MVD improves patients' quality of life, transposition should be recommended. Prediction of spasm-free time could relieve the anxiety of postoperative patients.