Search Results (41)

Neurovascular compression syndromes (NVCS), including trigeminal neuralgia (TN) and hemifacial spasm (HFS), are characterized by disabling symptoms caused by vascular compression of cranial nerves. Although microvascular decompression is an established treatment, mechanisms linking neurovascular compression to abnormal neural activity remain incompletely understood. In this review, we integrate evidence from microanatomical, electrophysiological, and computational studies to provide a mechanistic framework for NVCS. Chronic vascular compression induces focal demyelination, redistribution of voltage-gated ion channels, ectopic impulse generation, and ephaptic transmission, leading to abnormal neuronal excitation. We further summarize emerging evidence that persistent peripheral hyperactivity may contribute to electrophysiological alterations in central neural circuits. Particular attention is given to computational approaches, including cable theory and axonal interaction models, which offer quantitative insights into abnormal synchronization and cross-excitation among nerve fibers. Recent findings regarding ion channel dysfunction, including familial TN associated with gain-of-function calcium channel variants, are also discussed. Collectively, these findings support an integrated model linking neurovascular compression to clinical manifestations, and highlight the value of combining electrophysiology and computational neuroscience to improve mechanistic understanding and to guide future therapeutic strategies for NVCS. Full article

Objectives: The facial nerve (FN) possesses one of the most intricate anatomical courses in the head and neck, traversing the brainstem, temporal bone, and parotid gland before terminating within the muscles of facial expression. Owing to its complex anatomy, marked anatomical variability, and frequent distortion by adjacent pathology, preservation of FN integrity remains a fundamental challenge in skull base, otologic, and head and neck surgery. This review aims to provide a comprehensive synthesis of the contemporary literature regarding the clinical anatomy of the FN and to examine how anatomical variation, pathology-induced distortion, surgical strategy, and emerging technologies influence nerve preservation and functional outcomes. Methods: A comprehensive narrative review of the literature was conducted using PubMed, Scopus, and Google Scholar. Publications from 1983 through 2026 were searched using combinations of keywords, including “facial nerve,” “facial nerve anatomy,” “anatomical variation,” “vestibular schwannoma,” “hemifacial spasm,” “parotid surgery,” “facial nerve injury,” “facial nerve reconstruction,” “facial reanimation,” “diffusion tensor imaging,” “intraoperative neurophysiological monitoring,” and “artificial intelligence.” Peer-reviewed anatomical, radiological, clinical, and review articles published in English were included, while conference abstracts and studies lacking direct anatomical or surgical relevance were excluded. Particular emphasis was placed on surgically relevant anatomical variations, pathology-related anatomical distortion, advanced imaging modalities, intraoperative neurophysiological monitoring, reconstructive techniques, and predictors of postoperative facial nerve function. Results: Facial nerve preservation was found to depend on the interplay between individual anatomical variability, disease-related anatomical distortion, and operative strategy. In vestibular schwannoma surgery, nerve displacement, capsular adhesion, and cystic tumor degeneration were consistently associated with increased surgical complexity and less favorable postoperative facial function. In hemifacial spasm, successful microvascular decompression relied on precise identification of neurovascular conflict at the root exit zone. Within the parotid gland, substantial variability in branching architecture and surgical landmarks contributed to an increased risk of iatrogenic injury. Advanced imaging techniques, particularly diffusion tensor imaging tractography, improved preoperative prediction of FN location, while intraoperative neurophysiological monitoring enabled real-time assessment of neural integrity and functional preservation. Emerging artificial intelligence-based predictive models demonstrated potential to enhance patient-specific surgical planning and prognostication. Conclusions: Contemporary facial nerve surgery has evolved toward an individualized, anatomy-driven, and function-preserving paradigm supported by advanced imaging, intraoperative monitoring, and reconstructive strategies. Detailed understanding of both normal FN anatomy and pathology-induced anatomical distortion remains essential for optimizing surgical decision-making, maximizing nerve preservation, and improving long-term functional outcomes. Future developments integrating multimodal imaging, predictive analytics, and artificial intelligence may further refine patient-specific management and enhance postoperative facial function. Full article

Background: Neurovascular compression syndromes (NVCS) represent a spectrum of disabling neurologic disorders caused by vascular or structural compression of cranial nerves, most commonly at the root entry zone. Conditions such as trigeminal neuralgia (TN), hemifacial spasm (HFS), and glossopharyngeal neuralgia (GN) are associated with significant pain, functional impairment, and reduced quality of life. This review provides a multidisciplinary, anatomically grounded overview of the pathophysiology, diagnosis, imaging, and contemporary management strategies for NVCS. Methods: A narrative review of the literature was conducted, synthesizing historical perspectives, neuroanatomy of the cerebellopontine angle, mechanisms of neurovascular conflict, advances in imaging and neuromonitoring, and current treatment modalities. Medical, percutaneous, surgical, radiosurgical, and neuromodulatory approaches were evaluated, with emphasis on patient selection and outcome considerations. Results: Neurovascular compression, most frequently arterial compression at the root entry zone, leads to focal demyelination, ephaptic transmission, and neuronal hyperexcitability. High-resolution Magnetic resonance imagin (MRI) remains the diagnostic gold standard. First-line management for TN and related syndromes typically includes pharmacotherapy, particularly sodium channel blockers. Refractory cases may benefit from percutaneous rhizotomy, balloon compression, stereotactic radiosurgery, or microvascular decompression (MVD), which offers the most durable relief in appropriately selected patients. Emerging technologies, including endoscopic visualization, advanced neuromodulation, and virtual reality-assisted surgical planning, continue to refine treatment precision and safety. Conclusions: Effective management of NVCS requires a comprehensive understanding of neuroanatomy, pathogenesis, and individualized risk–benefit profiles. A multidisciplinary, stepwise approach optimizes outcomes and improves quality of life in patients with these complex disorders. Full article

Background: We aimed to investigate the prevalence and clinical significance of pontine microtubular signal intensity (MSI), presumed dilated perivascular or perineural spaces, in patients with hemifacial spasm (HFS) using high-resolution MRI using proton density-weighted imaging (HR-PDI). Methods: We retrospectively analyzed 438 patients with unilateral HFS who underwent microvascular decompression (MVD) and preoperative HR-PDI. MSI was defined as a linear or curvilinear hyperintense lesion along the presumed course of the intraparenchymal facial nerve fascicles within the pons on HR-PDI. The presence and laterality of MSI were evaluated by consensus between two reviewers and classified according to their relationship to the symptomatic side of HFS as ipsilateral (same side as the facial spasm), contralateral (opposite side), or bilateral. Clinical characteristics, surgical findings, and postoperative outcomes were compared according to the presence of ipsilateral MSI. A control group of 307 subjects who underwent HR-PDI for non-central neurologic symptoms was included to assess the prevalence of MSI. Multivariable logistic regression analysis was performed to identify factors associated with immediate postoperative improvement after MVD. Results: MSI was more frequently observed in patients with HFS than in controls after adjusting age and sex (OR, 3.78; 95% CI, 2.747–5.197; p < 0.001). Ipsilateral MSI was identified in 267 of 438 patients (61.0%). Patients with ipsilateral MSI showed a significantly higher frequency of contralateral MSI (p < 0.001) and vertebralartery-related compression (p = 0.002). Immediate postoperative improvement after MVD was less frequent in patients with ipsilateral MSI than in those without MSI (77.5% vs. 86.5%, p = 0.019). Multivariable logistic regression analysis demonstrated that ipsilateral MSI was independently associated with a lower likelihood of immediate postoperative improvement (OR, 0.411; 95% CI, 0.222–0.759; p = 0.005). However, long-term surgical outcomes were not significantly different according to the presence of MSI. Conclusions: Pontine MSI on HR-PDI is more frequently observed in patients with HFS and is associated with a lower likelihood of immediate postoperative improvement and a tendency toward delayed recovery after MVD but not with poorer long-term outcomes. These findings suggest that MSI may represent microstructural or neurofluidic alterations along the pontine facial nerve pathway and may serve as an imaging marker of delayed recovery dynamics. Full article

Background: In the last few decades, microvascular decompression has been proven to be one of the best therapeutic options in the management of neurovascular compression syndromes, especially trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia. However, higher rates of recurrences and morbidities have been recorded postoperatively. In the thorough search for better solutions, the option of adjuvant QEVO^® endoscopy has arisen as a very promising alternative. Methods: In this study, a retrospective single-center observational analysis was conducted, comprising patients who underwent microvascular decompression for trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia at our institution, between January 2020 and November 2025. Demographical data and outcomes of therapeutic management were statistically analyzed and presented accordingly. Results: A total of 40 patients diagnosed with neurovascular compression syndromes were neurosurgically treated in our center, and the most common diagnosis was represented by trigeminal neuralgia, identified in 32 patients (80%). Another five (12.5%) patients underwent microvascular decompression for hemifacial spasm, two (5%) patients were treated for combined trigeminal neuralgia and hemifacial spasm, and one patient (2.5%) for glossopharyngeal neuralgia. Arterial conflict was the triggering factor in the majority of cases, and no postoperative mortality was recorded. In patients treated using adjuvant QEVO endoscopy, the identification of hidden conflicts may be facilitated. Furthermore, the use of the QEVO endoscope allowed the identification of additional neurovascular conflicts and influenced intraoperative management in a subset of patients. Conclusions: Notwithstanding the medical literature suggesting that the main influential factor for therapeutic success is the vessel type and the pattern of compression, many authors identified the cornerstone of favorable outcomes as being endoscopic assistance. Nevertheless, this adjuvant factor has had a positive impact on the majority of patients. Full article

Cervical dystonia (CD), blepharospasm (BSP), and idiopathic hemifacial spasm (HFS) are focal hyperkinetic movement disorders with distinct underlying mechanisms. While CD and BSP involve central network dysfunctions within the basal ganglia-thalamo-cortical and cerebellar circuits, HFS primarily results from peripheral facial nerve hyperexcitability. Still, people living with all three conditions often struggle with mood issues like depression and anxiety, which can originate from both the burden of illness and changes in brain biology. We studied 61 patients (CD, n = 30; BSP, n = 9; HFS, n = 22) and assessed depression and anxiety before and three weeks after botulinum neurotoxin type A (BoNT-A) therapy, considering injection site and dose. BoNT-A significantly reduced depressive and anxiety symptoms across all groups, regardless of disease type, dose, or glabellar injection. These psychiatric improvements were not associated with the degree of motor symptom reduction, suggesting a partially independent mechanism of mood modulation. Our findings indicate that BoNT-A’s mood benefits may extend beyond local motor effects, possibly involving broader sensorimotor-limbic interactions. These results highlight the therapeutic potential of BoNT-A for addressing non-motor symptoms in both dystonic and non-dystonic hyperkinetic disorders. Future studies employing imaging and neurophysiological methods are necessary to explain the neural pathways underlying these effects. Full article

(1) Background: Hemifacial spasm (HFS) is most commonly caused by neurovascular compression at the root exit zone (REZ) of the facial nerve; however, isolated compression along the distal cisternal segment is uncommon and remains poorly characterized. This study aimed to analyze the clinical features, intraoperative neurophysiological patterns, and surgical outcomes of patients with HFS caused by cisternal segment arterial compression. (2) Methods: Among 874 patients who underwent microvascular decompression (MVD) for HFS, 18 (2.1%) were identified as having isolated neurovascular conflict at the cisternal segment, all involving the anterior inferior cerebellar artery (AICA). Clinical characteristics, offender location, intraoperative monitoring results including lateral spread response (LSR), brainstem auditory evoked potentials, and postoperative outcomes were retrospectively evaluated. A standardized Teflon interposition technique was used in all cases. (3) Results: Postoperatively, 83.3% of patients experienced immediate spasm relief, and at the latest available follow-up, 94.4% achieved significant improvement without severe complications. (4) Conclusions: Although rare, cisternal segment arterial compression can produce typical HFS and should be considered when REZ compression is unclear or when intraoperative neuromonitoring does not respond as expected. Microvascular decompression using Teflon interposition is a safe and effective treatment option for this anatomically challenging offender location. Full article

Hemifacial spasm (HFS) is a cranial nerve disorder characterized by involuntary contractions of muscles innervated by the facial nerve. Botulinum toxin type A (BoNT-A) is widely used for symptom control. Although local diffusion is well established, the extent and clinical relevance of BoNT-A spread to contralateral muscles remain unclear. This study aimed to investigate the contralateral neuromuscular effects of BoNT-A in patients undergoing long-term treatment with BoNT-A. This retrospective cross-sectional study included 39 patients with HFS (mean age, 58.6 ± 8.5 years). Bilateral compound muscle action potentials (CMAPs) were recorded before and four weeks after the BoNT-A injection. Single-fiber electromyography (SFEMG) jitter and mean consecutive difference (MCD) were evaluated contralaterally using concentric needle electrodes. Patients were categorized as first-time (n = 10) or long-term (n = 29; treatment duration: 1–20 years) BoNT-A recipients. Contralateral CMAP amplitudes decreased by 21.1% post-injection (p < 0.001). MCD increased from 33.2 ± 5.6 to 37.0 ± 5.3 µs (p < 0.001), and jitter rose by 81%, from 7.9 ± 6.2 to 14.3 ± 8.1 µs (p < 0.001). The percentage increase in MCD was significantly higher in long-term versus first-time patients (12.7% vs. 7.5%; p = 0.039), suggesting a cumulative neuromuscular effect. Spontaneous myokymia or fasciculations were clinically observed in four long-term patients. These findings provide electrophysiological evidence that unilateral BoNT-A injections may induce neuromuscular transmission abnormalities in the contralateral facial muscles. This effect appears more pronounced in chronically treated individuals, highlighting the need for awareness of potential bilateral spread when planning long-term therapy. Full article

Botulinum toxin is a neurotoxin that is used in the treatments for several medical conditions, such as dystonia, spasticity, hemifacial spasm, overactive bladder, and hyperhidrosis. This toxin can potentially treat several pain disorders through botulinum toxin’s ability to inhibit the release of pro-nociceptive neurotransmitters into the synaptic cleft and its possible action on the central nervous system. This narrative review addresses the use of botulinum toxin in treating primary and secondary headaches and facial pain disorders. The highest level of evidence supporting its use varies among the headache and facial pain disorders: chronic migraine (multicenter, double-blind, placebo-controlled studies), trigeminal neuralgia (double-blind, placebo-controlled studies), post-traumatic headache (double-blind, placebo-controlled study), cluster headache (open-label clinical trials), nummular headache (open-label clinical trial), headache attributed to craniocervical dystonia (prospective cohort study), new daily persistent headache (retrospective cohort study), hemicrania continua, and SUNCT and SUNA (case reports). The site of toxin application and the doses used vary among the studies and depending on headache type. Botulinum toxin has been shown to be safe in different studies, with generally mild adverse reactions. Full article

Previous randomized controlled trials (RCTs) investigating Botulinum toxin A (BoNT-A) for treatment of hemifacial spasm (HFS) have primarily focused on symptom relief and quality-of-life improvement. However, head-to-head comparisons of different BoNT-A formulations, particularly in terms of onset, duration of action, and efficacy, remain limited. We conducted a 12-week prospective, randomized controlled trial comparing the efficacy and safety of 33.33 units of Neubotulinum toxin A (Neu-BoNT-A) with 100 units of Abobotulinum toxin A (Abo-BoNT-A) in the treatment of HFS. A total of 87 patients were enrolled between September and December 2024. Neu-BoNT-A and Abo-BoNT-A exhibited similar onset and duration of action [5.0 ± 0.9 vs. 6.2 ± 0.7 days, respectively (p = 0.33)]. After 12 weeks of treatment, Neu-BoNT-A demonstrated superior efficacy in reducing the daily duration of HFS (2.00 ± 0.06 vs. 1.42 ± 0.10 h/day, p < 0.001) and improving sleep duration (1.37 ± 0.01 vs. 1.06 ± 0.01 h/day, p < 0.001). However, Abo-BoNT-A was associated with significantly lower absolute daily disability time compared to Neu-BoNT-A (11.4 vs. 1.2 min/day, p < 0.001). No serious adverse events were observed. Both Neu-BoNT-A and Abo-BoNT-A were safe and effective in treating HFS. However, Neu-BoNT-A was more effective in HFS with minimal symptoms without disability and Abo-BoNT-A more effective in HFS with greater duration of disability. Full article

Background: Repetitive intramuscular injections of botulinum neurotoxin (BoNT) have become the treatment of choice for a variety of disease entities. But with the onset of BoNT therapy, the natural course of a disease is obscured. Nevertheless, the present study tries to analyze patients’ “suspected” course of disease severity under the assumption that no BoNT therapy had been performed and compares that with the “experienced” improvement during BoNT treatment. Methods: For this cross-sectional study, all 112 BoNT long-term treated patients in a botulinum toxin out-patient department were recruited who did not interrupt their BoNT/A therapy for more than two injection cycles during the last ten years. Patients had to assess the remaining severity of their disease as a percentage of the severity at onset of BoNT therapy and to draw three different graphs: (i) the CoDB-graph showing the course of severity of patient’s disease from onset of symptoms to onset of BoNT/A therapy, (ii) the CoDA-graph illustrating the course of severity from onset of BoNT/A therapy until recruitment, and (iii) the CoDS-graph visualizing the suspected development of disease severity from onset of BoNT/A therapy until recruitment under the assumption that no BoNT/A therapy had been performed. Three different types of graphs were distinguished: the R-type indicated a rapid manifestation or improvement, the C-type a continuous worsening or improvement, and the D-type a delayed manifestation or response to BoNT therapy. Four patient subgroups (cervical dystonia, other cranial dystonia, hemifacial spasm, and the migraine subgroup) comprised 91 patients who produced a complete set of graphs which were further analyzed. The “experienced” improvement and “suspected” worsening of disease severity since the onset of BoNT/A therapy were compared and correlated with demographical and treatment related data. Results: Improvement was significant (p < 0.05) and varied between 45 and 70% in all four patient subgroups, the “suspected” worsening was also significantly (p < 0.05) larger than 0, except in the migraine patients and varied between 10 and 70%. The “total benefit” (sum of improvement and prevented “suspected” worsening) was the highest in the other cranial dystonia group and the lowest in the migraine subgroup. The distributions of R-,C-,D-type graphs across CoDB-, CoDS-, and CoDB-graphs and across the four patient subgroups were significantly different. Conclusions: (i) Most BoNT long-term treated patients have the opinion that their disease would have further progressed and worsened if no BoNT/A therapy had been performed, (ii) The type of response to BoNT/A is different across different subgroups of BoNT/A long-term treated patients. Full article

Movement disorders such as cervical dystonia, blepharospasm, and hemifacial spasm negatively impact the quality of life of people living with these conditions. Botulinum toxin (BoNT) injections are commonly used to treat these disorders. We sought to describe patient characteristics, BoNT utilization, and potential adverse events (AEs) among patients with cervical dystonia, blepharospasm, and hemifacial spasm using Optum’s de-identified Clinformatics^® Data Mart Database. Patients were required to have a diagnosis of the specific condition plus evidence of treatment with BoNT between 8/1/2010 and 5/31/2022. Cervical dystonia patients were commonly females (76%) and aged 45 and older (78%); both blepharospasm and hemifacial spasm patients were commonly females (both 69%) and aged 65 and older (61% and 56%, respectively). Anticholinergics were commonly used (65–82% across cohorts), as were peripheral muscle relaxants for cervical dystonia patients specifically (31%). The median number of injections per year was 2 with the median weeks between injections being between 13 and 15. Of the AEs evaluated, dyspnea was identified frequently across all the cohorts (14–20%). The findings were similar for different BoNT formulations. More research is needed to thoroughly describe BoNT utilization, such as the doses injected, and to optimize treatment for patients with these conditions. Full article

Neurological complications after the coronavirus disease 2019 (COVID-19) vaccine administration have been reported. However, the incidence rates of these complications have not been compared in vaccinated and unvaccinated individuals. This study used a nationwide cohort from South Korea to investigate the incidence and prognostic factors of facial-related neurological disorders, such as facial palsy, trigeminal neuralgia, and hemifacial spasms, after COVID-19 vaccination. A population-based cohort design was used to examine data from a randomly selected 50% of the adult population in Seoul, South Korea. Information on demographics, vaccination status, vaccination type, and medical history was collected. The incidence rates and adjusted hazard ratios (aHRs) for facial-related neurological disorders were calculated. This study included 2,482,481 adults, 85.94% of whom were vaccinated. Vaccinated individuals showed a higher incidence of facial palsy, hemifacial spasm, and trigeminal neuralgia than unvaccinated individuals, with significant aHRs of 1.821, 3.203, and 6.621, respectively. Dyslipidemia, female sex, and young age were identified as risk factors for hemifacial spasms and trigeminal neuralgia. This study demonstrates an increased incidence of facial-related neurological disorders after COVID-19 vaccination, particularly among individuals with dyslipidemia and younger women. These findings underscore the need for further investigations into the mechanisms and management of vaccine-related neurological issues. Full article

(1) Background: Sequels of facial palsy lead to major psychosocial repercussions, disrupting patients’ quality of life (QoL). Botulinum toxin (BoNT) injections can permit us to treat long-standing facial palsy, improving facial symmetry and functional signs including synkinesis and contractures. (2) Methods: The main aim of this study was to assess the evolution of the QoL for patients with long-standing facial palsy before, at 1 month, and at 4 months after BoNT injections by using three questionnaires (HFS-30, FaCE, and HAD). The other goals were to find clinical factors associated with the improvement in the QoL and to assess the HFS-30 questionnaire for patients with unilateral facial palsy (3) Results: Eighty-eight patients were included in this study. There was a statistically significant improvement in QoL at 1 month after injections, assessed using the three questionnaires. This improvement was sustained at 4 months after the injections, with a statistically significant difference for the HFS-30 and FaCE questionnaires. (4) Conclusions: This study showed that the BoNT injections lead to a significant increase in the QoL of patients with unilateral facial palsy. This improvement is sustained 4 months after the injections. Full article

The anterior inferior cerebellar artery (AICA) is situated within the posterior cranial fossa and typically arises from the basilar artery, usually at the pontomedullary junction. AICA is implicated in various clinical conditions, encompassing the development of aneurysms, thrombus formation, and the manifestation of lateral pontine syndrome. Furthermore, owing to its close proximity to cranial nerves within the middle cerebellopontine angle, AICA’s pulsatile compression at the root entry/exit zone of cranial nerves may give rise to specific neurovascular compression syndromes (NVCs), including hemifacial spasm (HFS) and geniculate neuralgia concurrent with HFS. In this narrative review, we undertake an examination of the influence of anatomical variations in AICA on the occurrence of NVCs. Significant methodological disparities between cadaveric and radiological studies (CTA, MRA, and DSA) were found, particularly in diagnosing AICA’s absence, which was more common in radiological studies (up to 36.1%) compared to cadaver studies (less than 5%). Other observed variations included atypical origins from the vertebral artery and basilar-vertebral junction, as well as the AICA-and-PICA common trunk. Single cases of arterial triplication or fenestration have also been documented. Specifically, in relation to HFS, AICA variants that compress the facial nerve at its root entry/exit zone include parabola-shaped loops, dominant segments proximal to the REZ, and anchor-shaped bifurcations impacting the nerve’s cisternal portion. Full article