Refining the predictive value of preoperative apparent diffusion coefficient (ADC) by whole-tumor analysis for facial nerve outcomes in vestibular schwannomas.

BACKGROUND: Apparent diffusion coefficient (ADC) in MRI has been shown to correlate with postoperative House-Brackmann (HB) scores in patients with vestibular schwannoma despite limited methodology. To rectify limitations of single region of interest (ROI) sampling, we hypothesize that whole-tumor ADC histogram analysis will refine the predictive value of this preoperative biomarker related to postoperative facial nerve function. METHODS: Of 155 patients who underwent resection of vestibular schwannoma (2014-2020), 125 patients were included with requisite clinical and radiographic data. After volumetric analysis and whole-tumor ADC histogram, regression tree analysis identified ADC cutoff for significant differences in HB grade. Outcomes were extent of resection, facial nerve function, hospital length of stay (LOS), and complications. RESULTS: Regression tree analysis defined three quantitative ADC groups (× 10-6 mm2/s) as high (> 2248.77; HB 1.7), mid (1468.44-2248.77; HB 3.1), and low (< 1468.44; HB 2.3) range (p 0.04). The mid-range ADC group had significantly worse postoperative HB scores and longer hospital LOS. Large tumor volume was independently predictive of lower rates of gross total resection (p <0.0001), higher postoperative HB score (p 0.002), higher rate of complications (p 0.04), and longer LOS (p 0.003). CONCLUSIONS: Whole-tumor histogram yielded a robust regression tree analysis that defined three ADC groups with significantly different facial nerve outcomes. This likely reflects tumor heterogeneity better than solid-tumor ROI sampling. Whole-tumor ADC warrants further study as a useful radiographic biomarker in patients with vestibular schwannoma who are considering surgical resection.

Localization of the Vertical Part of the Facial Nerve in the High-Resolution Computed Tomography During Pediatric Cochlear Implantation.

BACKGROUND: This study proposed a classification of the vertical portion of the facial nerve (VPFN) location, incorporating the previous classifications regarding the posterior-to-anterior and medial-to-lateral dimensions. We also evaluated the implication of this proposed classification on the round window visibility during pediatric cochlear implantation (CI). METHODS: It was a retrospective multicenter observational cohort study. This study included 334 cases that underwent CI between 2015 and 2022 at multiple referral institutes. Two physicians evaluated the preoperative computed tomography images of 334 patients and determined the radiological type of the VPFN. These types were matched with intraoperative round window accessibility. RESULTS: The Spearman's correlation coefficient showed a strong correlation between the proposed VPFN type and the intraoperative round window visibility, as the P-value was <.001. CONCLUSION: This classification could provide the surgeon preoperatively with the precise location of the VPFN in the lateral-to-medial and posterior-to-anterior dimensions. Furthermore, this location classification of the VPFN was significantly correlated with intraoperative round window accessibility, with an accuracy of 90.42%. Therefore, types C and D were expected to have difficult accessibility into the round window, and more surgical interventions were needed to modify the posterior tympanotomy or use other approaches.

Diagnostic Challenges and Imaging Considerations for Intraparotid Facial Nerve Schwannoma: A Case Report and Literature Review.

BACKGROUND A mass in the parotid gland usually indicates parotid gland neoplasia. Warthin tumors or pleomorphic adenomas are common differential diagnoses. Less frequently, other differential diagnoses and sites of origin are considered. Schwannomas are rare, benign tumors in the head and neck region. Even more rarely, these tumors occur in the intraparotid course of the facial nerve. In the following, we report about 2 patients in whom a mass in the right parotid gland was found incidentally during magnetic resonance imaging (MRI). CASE REPORT We reviewed data from the literature on intraparotid facial nerve schwannomas (IPFNS) and compared them with those from our cases. The focus was on data such as clinical history, clinical symptoms, electroneurography, and various imaging modalities, such as ultrasonography and MRI combined with diffusion-weighted imaging. CONCLUSIONS It is challenging to distinguish facial nerve schwannomas from other neoplasms. Patient's history, clinical symptoms, MRI examination with diffusion-weighted imaging, and high-resolution ultrasound imaging are decisive factors for diagnosis and should be performed when IPFNS is suspected. Diagnosis and therapy for IPFNS remain challenging. A wait-and-scan approach could be an option for patients with small tumors and good facial nerve function. On the other hand, patients with advanced tumors associated with limited facial nerve function can benefit from surgical approaches or stereotactic radiosurgery.

Evaluating magnetic resonance imaging characteristics and risk factors for hemifacial spasm.

PURPOSE: The specific neurovascular compression (NVC) event responsible for the symptomatic manifestation of hemifacial spasm (HFS) remains difficult to assess accurately using magnetic resonance imaging (MRI). We aim to evaluate the MRI characteristics of HFS. METHOD: We retrospectively included patients with HFS and divided them into a test group (n = 186) and a validation group (n = 28). The presence, severity, and offending vessel type of NVC in each portion, and the orientation of the offending vessel around the facial nerve, were recorded. Conditional logistic regression analyses were performed to evaluate correlations using test group. The validation group was used to verify whether our findings improved diagnostic performance. RESULTS: Deformity in the proximal cisternal segment was significantly correlated with HFS occurrence (odds ratio [OR]: 256.58, p = .002), whereas contact was not (p = .233). Both contact and deformity in the root detachment point (OR: 19.98 and 37.22, p < .001 and p = .013, respectively) or attached segment (OR: 4.99 and 252.52, p = .001 and p < .001, respectively) were significantly correlated with HFS occurrence. Our findings improved specificity, positive predictive value, and accuracy of diagnosis than conventional diagnostic methods. The vertebral artery predominantly compress the facial nerve in the inferior-anterior position, the anterior inferior cerebellar artery predominantly in the inferior position, the posterior inferior cerebellar artery predominantly in the inferior position, vein predominantly in the posterior-superior position. CONCLUSIONS: This study further demonstrates that within the susceptible portion of facial nerve, different portions of the nerve respond differently to NVC. Each offending vessel has its own preferred conflict orientation. Our study offers reference for neurosurgeons in diagnosis and treatment.

Significant tumor compression of the middle cerebellar peduncle is associated with worse facial nerve outcomes and lower extent of resection in surgery for medium-sized vestibular schwannomas - A radiographic analysis of a case series.

BACKGROUND AND OBJECTIVE: Optimizing the extent of resection (EOR) and facial nerve outcomes (FNO) remain a challenge in medium to large vestibular schwannomas (VS). Currently, tumor size has been the only consistently reported factor predicting FNO and EOR. Here, we sought to evaluate whether the degree of the tumor's compression on the middle cerebellar peduncle (PC) influences FNO and EOR in medium to large VS. METHODS: This retrospective case series included 99 patients who underwent surgical resection of their VSs from 2014 to 2022. Preoperative MR imaging was used to measure the degree of PC. Patient medical records were queried to determine the EOR and FNO. RESULTS: Patients with unfavorable FNO (HB 3 +) immediately post-op had significantly greater PC than those with favorable FNO (19.9 vs. 15.4 mm, P = .047). This significance was not observed at the last follow-up but there was a trend. When medium-sized tumors (15-30 mm) were analyzed separately, patients with unfavorable FNO immediate post-op and at last follow-up had significantly greater PC than their favorable counterparts (14.1 vs 8.7 mm). Significantly greater PC was also observed in patients who underwent subtotal resection (20.7 mm) compared to near (14.3 mm) and gross total resection (10.8 mm). Multivariate analyses confirmed these findings in medium-sized tumors, but not large-sized tumors. CONCLUSION: The degree of PC as measured on preoperative imaging can predict FNO and EOR in medium-sized vestibular schwannomas. Medium-sized tumors with > 15 mm of PC likely will have worse FNO and lower EOR.

[Image Diagnosis for Hemifacial Spasm].

Cisternography using heavy T2-weighted images from 3-Tesla magnetic resonance imaging(MRI)and three-dimensional time-of-flight MR angiography(3D TOF MRA)is useful for identifying conflicting vessels in primary hemifacial spasm(HFS). Cisternography provides high-signal images of the cerebrospinal fluid and low-signal images of the cranial nerves and cerebral blood vessels, whereas 3D TOF MRA provides high-signal images with only vascular information. The combination of these two methods increases the identification rate of conflicting vessels. The neurovascular conflict(NVC)site in HFS is where the facial nerve exits the brainstem. However, on MRI, the true NVC site is often more proximal than the facial nerve attachment to the brainstem. On preoperative MRI, it is important to not miss the blood vessels surrounding the proximal portion of the facial nerve. If multiple compression vessels or deep vessels are located in the supraolivary fossette, they may be missed. Coronal section imaging and multiplanar reconstruction(MPR)minimize the chances of missing a compression vessel. Preoperative MRI and CT can also provide various other information, such as volume of the cerebellum, presence of emissary veins, shape of the petrosal bone, and size of the flocculus.

Evaluation of facial nerve perineural spread from cutaneous squamous cell carcinoma using 3T MR neurography.

INTRODUCTION: Perineural spread (PNS) is a rare but potentially fatal consequence of cutaneous squamous cell carcinoma (cSCC) of the head and neck. We aimed to evaluate the accuracy of 3T MR neurography in detecting and defining the extent of facial nerve (VII) PNS from cSCC, and highlight characteristic radiological features in peripheral branches to improve early diagnosis. METHODS: Single-institution retrospective review of 38 patients with clinical, radiological, and/or histopathological findings consistent with VII PNS from cSCC who underwent pre-operative 3T MR neurography. RESULTS: Compared to histopathology (gold standard), 3T MR neurography had a sensitivity of 89% and positive predictive value of 97%. In true-positive cases (n = 33), zonal extent was correctly identified in 100%. Seventy-nine% had simultaneous trigeminal nerve (V) PNS, mostly involving the auriculotemporal branch of the mandibular nerve (64%). When the causative lesion was absent (n = 23), the extra-temporal VII demonstrated asymmetrical enhancement alone (n = 6), bulky expansion (n = 8), or extra-neural spread (n = 9). Peripheral VII branch involvement, particularly the buccal and zygomatic, was readily identified using known anatomical landmarks. CONCLUSION: 3T MR neurography is highly accurate in evaluating VII PNS from cSCC, and thus should be specifically requested by physicians if suspicious for disease. Coexistent V PNS was common, highlighting the need to examine V branches to allow complete treatment planning. The unique radiological patterns identified showcases disease progression. As early detection improves patient outcomes, the radiologist must look for peripheral VII involvement in specific anatomical areas, which is within the capabilities of 3T MR neurography.

How to face the hemifacial spasm: challenges and misconceptions.

Hemifacial spasm (HFS) is characterised by intermittent, brief or sustained, repetitive contractions of the muscles innervated by one facial nerve. It is one of the most frequent movement disorders affecting the face. However common and allegedly straightforward to diagnose, it might reveal as a challenge for clinicians in various situations. Indeed, it often needs prior exclusion of many other movement disorders affecting the face, with frequent phenomenological overlaps with blepharospasm, post-facial palsy, facial motor tics, etc. The clinical diagnosis shall be supported by modern brain imaging techniques, and sometimes electromyography, as some particular aetiologies may require specific treatment. Primary forms are associated with vascular compression of the ipsilateral seventh cranial nerve, whereas secondary forms can be caused by any injury occurring on the facial nerve course. This article proposes a global and organised approach to the diagnosis, and the ensuing therapeutic options, as many practitioners still use some inefficient medications when they encounter a case of facial spasm.

The clinical availability of facial nerve enhancement in temporal bone MRI for the patients of idiopathic acute peripheral facial palsy.

PURPOSE: This study is to evaluate the duration of facial nerve enhancement in gadolinium-enhanced temporal bone MRI after the onset of acute facial palsy. METHODS: Gd-enhanced MRI imagines were examined in 13 patients with idiopathic acute facial palsy within 14 days after the onset. The degree of facial nerve function was measured according to the House-Brackmann (H-B) grading system at their first visit at outpatient clinic. The follow-up MRI was taken about 16.5 months (7-24 months) after onset of disease. The degree of facial nerve enhancement was measured with signal intensity (SI) which was quantitatively analyzed using the region-of-interest (ROI) measurements for each segment of the facial nerve. SI was statistically analyzed by comparing SI values of contralateral site and ipsilateral site using the paired t test with SPSS program. RESULTS: The gadolinium enhancement was statistically increased at labyrinthine segment and geniculate ganglion area of facial nerve at initial temporal bone MRI. The gadolinium enhancement was statistically decreased at all the segments of facial nerve except tympanic segment (p < 0.05) at follow-up MRI. CONCLUSIONS: The facial nerve enhancement in Gd-enhanced MRI images prolonged more than 21 months of the onset. The newly developed pathologic lesions of acute facial palsy especially occur at the site of labyrinthine and geniculate ganglion.

Predicting value for incomplete recovery in Bell's palsy of facial nerve ultrasound versus nerve conduction study.

OBJECTIVE: This longitudinal study aims at assessing the predictive value of facial nerve high-resolution ultrasound (HRUS) for incomplete clinical recovery in patients with Bell's palsy, the most common facial nerve disease. METHODS: We prospectively enrolled 34 consecutive patients with Bell's palsy. All patients underwent neurophysiological testing (including facial nerve conduction study) and HRUS evaluations 10-15 days (T1), one month (T2), and three months (T3) after the onset of Bell's palsy. Patients who did not experience complete recovery within three months were also evaluated after six months (T4). We have then compared the accuracy of HRUS with that of the facial nerve conduction study in predicting incomplete clinical recovery at three and six months. RESULTS: At T1, the facial nerve diameter, as assessed with HRUS, was larger on the affected side than on the normal side, particularly in patients with incomplete recovery at T2, T3 and T4. ROC curve analysis, however, showed that the facial nerve diameter at T1 had a lower predictive value than the facial nerve conduction study for an incomplete clinical recovery at three (T3) and six (T4) months. Still, the facial nerve diameter asymmetry, as assessed with HRUS, had a relatively high negative predictive value (thus indicating a strong association between normal HRUS examination and a good prognosis). CONCLUSIONS: Although HRUS shows abnormally increased facial nerve diameter in patients in the acute phase of Bell's palsy, the predictive value of this technique for incomplete clinical recovery at three and six months is lower than that of the nerve conduction study. SIGNIFICANCE: Nerve ultrasound has a low predictive value for incomplete clinical recovery in patients with Bell's Palsy.

Contrast-enhanced MRI findings of patients with acute Bell palsy within 7 days of symptom onset: A retrospective study.

The brain magnetic resonance imaging (MRI) findings seen in patients with Bell palsy are abnormal contrast enhancement of affected facial nerves. Previous studies were conducted on a few patients, mainly those who had experienced palsy for several weeks. This study investigated the diagnostic usefulness of MRI by examining MRI findings of acute Bell palsy (within 7 days of symptom onset) in a large cohort. Among the patients with Bell palsy (idiopathic unilateral facial palsy) who visited the hospital, 123 patients who underwent contrast-enhanced MRI of the internal auditory canal within 7 days of symptom onset were reviewed retrospectively. MRI examination results were investigated along with the patient's clinical symptoms and electrodiagnostic test results. Based on the MRI results, the frequency of abnormal contrast enhancement and contrast-enhanced areas were investigated. Of the 123 patients, 13 (11%) had normal brain MRI results, and 110 (89%) had abnormal findings. The frequency of abnormal contrast enhancement was not significantly associated with test timing (P = .56). Of the 110 patients with abnormal findings, 65 (59%) showed contrast enhancement in the labyrinthine segment and 36 (33%) in both the labyrinthine segment and geniculate ganglion. Most patients with Bell palsy who are in the acute phase showed abnormal contrast enhancement in their facial nerves, and similar findings were even observed in the examination conducted on the day of symptom onset. Brain MRI helps in the diagnosis of acute Bell palsy.

Irreversible facial nerve palsy as a revelator ofparotid gland cancer.

<br><b>Introduction:</b> Bell's palsy is still the diagnosis of exclusion. In most patients it does not progress, it is unilateral, and selflimiting. Additionally, the majority of patients recover spontaneously within 3 weeks. It is well known that all patients with irreversible facial nerve paresis (FNP) need further examinations to exclude the organic, infectious, metabolic, and autoimmunological causes of the palsy. The goal of the study was to assess the frequency of malignancies hidden under the diagnosis of "Bell's palsy".</br> <br><b>Aim:</b> We aimed to create a diagnostic algorithm to avoid failures concerning patients whose only symptom of parotid gland cancer was irreversible FNP.</br> <br><b>Material and methods:</b> We analyzed 253 consecutive patients with FNP treated in our department in the last 5 years. The subject of the study was "Bell's palsy" cases. All patients with irreversible FNP were reassessed in 6-12 months. We underlined all shortcomings in the diagnostics of those in whom malignancies were found in MRI of the neck and presented the proposal for a diagnostic algorithm to avoid missing such an entity.</br> <br><b>Results:</b> Bell's palsy was observed in 157/253 patients (62.06%), in 36/157 (22.92%) it remained permanent. In 4/36 patients (11.11%) with irreversible FNP, which constituted 2.54% of all "Bell's palsy" cases, parotid gland deep lobe mass was found in MRI. In one patient, infiltration of the skull base was diagnosed. Adenoid cystic carcinoma was confirmed in final histopathology in all cases.</br> <br><b>Conclusions:</b> Our experience has shown that irreversible FNP can be a revelator of the malignant tumor located in the deep lobe of the parotid gland. Contrast-enhanced MRI covering intra- and extracranial segments of the facial nerve should be ordered in all cases of FNP without recovery after 4 months. Repeated imaging should be considered in undiagnosed cases. The main point of our study is to underline that the assessment of the deep lobe of the parotid gland with MRI should be included in the standard diagnostic protocol in all irreversible "Bell's palsy" cases.</br>.

Application of diffusion tensor imaging of the facial nerve in preoperative planning for large vestibular schwannoma: a systematic review.

The accurate identification and preservation of the facial nerve (FN) during vestibular schwannoma (VS) surgery is crucial for maintaining facial function. Investigating the application of diffusion tensor imaging (DTI) in preoperative planning for large VS surgery is provided. PubMed, Cochrane Library, Science Direct, ISI Web of Science, Embase, and additional sources were searched to identify cohort studies about the preoperative DTI usage for the FN tracking before large VS (≥ 2.5 cm) surgery published between 1990 and 2023. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed; the Newcastle-Ottawa Scale was used to assess the risk of bias and to evaluate limitations based on selection/outcome biases. A total of 8 publications yielding 149 VS (mean size 3.66 ± 0.81 cm) were included. Surgical concordance with preoperative DTI FN tracking was 91.67% (range 85-100%). Overall DTI reliability was 88.89% (range 81.81-95.83%). Larger tumor size predicted either DTI inaccurate finding or complete DTI failure (p = 0.001). VS size above > 3.5 cm was associated with a higher risk of DTI failure (p = 0.022), with a higher risk of inaccurate DTI finding preoperatively (p = 0.033), and with a higher House-Brackman score postoperatively (p = 0.007). Application of DTI in larger VS surgery is a valuable FN identification along with electrophysiological monitoring and neuronavigation, therefore also in its preservation and in lowering risk of complications. DTI represents a valuable adjunct to electrophysiological monitoring and neuronavigation in FN identification, applicable not only for smaller, but also larger VS.

Analysis of mastoid portion of facial nerve course in temporal bone using computed tomography.

<b>Introduction:</b> The facial nerve (FN) follows a complex route in the temporal bone. Successful temporal bone surgery requires knowledge of its course which can be achieved using imaging methods such as computed tomography. This investigation aims to analyze the FN course in its mastoid portion and second genu and the frequency of its atypical course.</br></br> <b>Material and methods:</b> This is a retrospective study that enrolled 104 CT scans of temporal bones of patients followed up in the outpatient clinic of the Otorhinolaryngology Department of Dentistry Faculty of the Medical University of Warsaw between 2020 and 2022. FN courses were classified as straight, bulging, or letter "S"-like. Other parameters estimated: </br> • position of the second genu according to the prominence of the lateral semicircular canal (classified as lateral, medial, or middle) and its distance from a line adjacent to the lateral semicircular canal was measured;</br> • the distance between the short process of the incus and the outermost point of the second genu;</br> • the course of the mastoid portion of FN and the location of SG in comparison to the tympanic portion of n. VII. The course was later classified as lateral, medial, or middle.</br></br> <b>Results:</b> Among the 104 assessed temporal bones, the course of the mastoid portion of FN was classified as bulging in 47 cases (45.2%). Straight and letter "S"-like courses were present in 41 (39.4%) and 16 (15.4%) cases, respectively. Deviation of the second genu according to the prominence of the lateral semicircular canal was medial in 86 cases (82.7%), and middle in 4 cases (3.8%). In the rest, second genu was paramedian to the prominence of the later circular canal. The mean distance between the short process of the incus and the outermost point of SG was 4.9 mm (0.73 mm). The mastoid portion was located laterally, medially, and in the middle of the tympanic portion plane in, respectively, 4.8%, 83.7%, and 11.5%. The second genu was located laterally, medially, and in the middle of the tympanic portion plane in 1.9%, 73.1%, and 25%, respectively. In conclusion, seven temporal bones (6.7%) of five patients presented with a lateral displacement of FN in relation to the established anatomical landmarks.</br></br> <b>Conclusions:</b> Although the atypical course of FN, including the lateral displacement of the mastoid portion, is rare, screening for it is crucial before surgical exploration.

To explore the pathogenesis of Bell's palsy using diffusion tensor image.

To explore the pathogenesis of Bell's palsy using the diffusion tensor image on 3.0 T MR. The healthy people and the patients with Bell's palsy underwent intraparotid facial nerve scanning by using the DTI and T1 structural sequence at 3.0 T MR. The raw DTI data were performed affine transformation and nonlinear registration in the common MNI152_T1 space and resampled to the 0.4 mm3 voxel size. A group of 4 spherical seed regions were placed on the intratemporal facial nerves in the common space, bilaterally and symmetrically. The DTI data in the common space were used to track the intratemporal facial nerve fibers by using TrackVis and its Diffusion Toolkit. Each tractography was used to construct the maximum probability map (MPM) according to the majority rule. The fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) were calculated and extracted on the basis of MPM. For healthy people, there was no significant difference in FA, MD, RD and AD of bilateral facial nerves. For patients with Bell's palsy, there was no significant difference in AD, there was significant difference in FA, MD and RD between the affected nerve and the healthy nerve (P < 0.02). This study showed that the myelin sheath injury of the intratemporal facial nerve is the main cause of Bell's palsy. Most neural axons are not damaged. The results may explain the pathogenesis of the Bell's palsy, which is self-limited for most cases.

Intra-parotid facial nerve neuroma, an overlooked differential for a parotid lesion.

Facial nerve neuromas rarely occur in the intra-parotid segment of the facial nerve and when they do, masquerade as a parotid lump. The imaging and clinical features of the intra-parotid facial neuroma overlaps with the more commonly encountered salivary gland neoplasms and is thus overlooked. However, if not recognized, may result in serious and avoidable adverse events for the patient if biopsied or surgically removed. These include pain, facial nerve palsy and cosmetic deformity. In this report, we present the case of a 47-year-old male patient with an intra-parotid facial nerve neuroma with images including computer tomography, magnetic resonance imaging and intra-operative photos. The lesion was eventually left in situ to avoid facial nerve palsy and preserve cosmesis. A discussion of the imaging characteristics and differential diagnoses is subsequently elaborated.

Imaging of Facial Nerve With 3D-DESS-WE-MRI Before Parotidectomy: Impact on Surgical Outcomes.

OBJECTIVE: The intra-parotid facial nerve (FN) can be visualized using three-dimensional double-echo steady-state water-excitation sequence magnetic resonance imaging (3D-DESS-WE-MRI). However, the clinical impact of FN imaging using 3D-DESS-WE-MRI before parotidectomy has not yet been explored. We compared the clinical outcomes of parotidectomy in patients with and without preoperative 3D-DESS-WE-MRI. MATERIALS AND METHODS: This prospective, non-randomized, single-institution study included 296 adult patients who underwent parotidectomy for parotid tumors, excluding superficial and mobile tumors. Preoperative evaluation with 3D-DESS-WE-MRI was performed in 122 patients, and not performed in 174 patients. FN visibility and tumor location relative to FN on 3D-DESS-WE-MRI were evaluated in 120 patients. Rates of FN palsy (FNP) and operation times were compared between patients with and without 3D-DESS-WE-MRI; propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to adjust for surgical and tumor factors. RESULTS: The main trunk, temporofacial branch, and cervicofacial branch of the intra-parotid FN were identified using 3D-DESS-WE-MRI in approximately 97.5% (117/120), 44.2% (53/120), and 25.0% (30/120) of cases, respectively. The tumor location relative to FN, as assessed on magnetic resonance imaging, concurred with surgical findings in 90.8% (109/120) of cases. Rates of temporary and permanent FNP did not vary between patients with and without 3D-DESS-WE-MRI according to PSM (odds ratio, 2.29 [95% confidence interval {CI} 0.64-8.25] and 2.02 [95% CI: 0.32-12.90], respectively) and IPTW (odds ratio, 1.76 [95% CI: 0.19-16.75] and 1.94 [95% CI: 0.20-18.49], respectively). Conversely, operation time for surgical identification of FN was significantly shorter with 3D-DESS-WE-MRI (median, 25 vs. 35 min for PSM and 25 vs. 30 min for IPTW, P < 0.001). CONCLUSION: Preoperative FN imaging with 3D-DESS-WE-MRI facilitated anatomical identification of FN and its relationship to the tumor during parotidectomy. This modality reduced operation time for FN identification, but did not significantly affect postoperative FNP rates.

Ventrolateral pontomedullary junction ischaemic stroke imitating isolated facial nerve palsy.

A 75-year-old woman presenting with unilateral lower motor neurone facial weakness was ultimately diagnosed with an ischaemic stroke at the pontomedullary junction affecting the facial nerve fascicles. Isolated, unilateral, upper and lower facial weakness is typically caused by lesions affecting the facial nerve, such as Bell's palsy, though rarely can be a manifestation of acute ischaemic stroke. It is important for neurologists and emergency providers to determine appropriately which patients with facial weakness require neuroimaging and which do not.

[Efficacy of CT-guided partial radiofrequency ablation of bilateral responsible cranial nerves in the treatment of Meige syndrome].

Objective: To evaluate the efficacy of CT-guided partial radiofrequency ablation of bilateral responsible cranial nerves in the treatment of Meige syndrome. Methods: The Clinical data of 56 patients with Meige syndrome in the Department of Pain Medicine, Affiliated Hospital of Jiaxing University from June 2019 to January 2023 were retrospectively analyzed [19 males and 37 females, aged 42-76 (58.6±8.3) years], including 51 cases of blepharospasm, 3 cases of oromandibular dystonia and 2 cases of blepharospasm concomitant with oromandibular dystonia. CT-guided partial radiofrequency ablation of bilateral responsible cranial nerves was performed on different types of Meige syndrome. And the efficacy and complications of the technique were observed. Results: Fifty-one patients with blepharospasm Meige syndrome underwent CT-guided radiofrequency of facial nerve through bilateral stylomastoid foramen punctures, the symptoms of blepharospasm disappeared completely, leaving bilateral mild and moderate facial paralysis symptoms. Three patients with oral-mandibular dystonia underwent CT-guided radiofrequency therapy by bilateral foramen ovale puncture of mandibular branches of trigeminal nerve, masticatory muscle spasm disappeared, the patients had no difficulty opening the mouth, and the skin numbness in bilateral mandibular nerve innervation area was left. Two cases of Meige syndrome with blepharospasm concomitant with oromandibular dystonia were treated by radiofrequency of facial nerve and mandibular branch of trigeminal nerve, and all symptoms disappeared. The patients were followed up for 1-44 months after the operation, and the symptoms of mild and moderate facial paralysis disappeared at (3.2±0.8) months after the operation, but the numbness did not disappear. Three patients with blepharospasm recurred at the 14, 18 and 22 months after the operation, respectively, while the rest cases did not recur. Conclusions: According to different types of Meige syndrome, CT-guided partial radiofrequency ablation of responsible cranial nerves can effectively treat the corresponding type of Meige syndrome. The complications are only mild and moderate facial paralysis which can be recovered, and/or skin numbness in the mandibular region.