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.

Schwannoma of the Zygomatic Branch of the Facial Nerve

SIGNIFICANCE STATEMENT

Facial nerve schwannoma is extremely uncommon. Despite its rarity, it is considered the most common facial nerve tumor and potentially affects any segment of the nerve. Presenting symptoms vary depending on the location of the neoplasm. Tumors pertaining to the extratemporal course of the nerve mainly appear as an asymptomatic parotid mass. We present a rare case of schwannoma of the zygomatic branch of the right facial nerve that was surgically resected, without facial nerve injury.

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.

Tumor localization is the important factor for recovery time of postoperative facial nerve paralysis in benign parotid surgery

OBJECTIVE

Facial nerve paralysis is the most problematic complication of surgery for parotid tumors. This study aimed to examine the progress of recovery from postoperative transient facial nerve paralysis (POFNP).

METHODS

Participants were 203 patients who developed POFNP after benign parotid surgery. A Kaplan-Meier showed the progress of recovery from paralysis. Factors involved in recovery were examined. For factors for which a significant difference was found, recovery from paralysis was examined over time.

RESULTS

Rates of recovery from paralysis were as follows: 28.6% of patients at 1 month, 58.3% at 3 months, 85.9% at 6 months, and 95.1% at 12 months after surgery. Deep lobe tumors were shown to be significantly associated with delayed recovery from paralysis. The relationship between tumor location and the time of recovery from was that deep lobe tumors had a significantly worse recovery from paralysis at 4 and 5 months after surgery.

CONCLUSION

Patients who develop POFNP must be informed about the progress of recovery and factors involved in recovery from paralysis. We believe that the results of the present study are a useful reference to that end.

Comparison of Stereotactic Radiosurgery and Hypofractionated Radiosurgery for Vestibular Schwannomas: A Meta-Analysis of Available Literature

BACKGROUND

Stereotactic radiosurgery (SRS) and recently, hypofractionated radiosurgery (hSRS) are increasingly utilized as treatment for vestibular schwannomas (VS). We performed a meta-analysis of literature comparing these modalities.

METHODS

The PubMed database of articles was searched for studies that compared SRS and hSRS in patients with VS. Variables analyzed include tumor control, hearing preservation, facial nerve preservation, trigeminal nerve preservation, and total complications. Heterogeneity across the studies was gauged using Higgins's inconsistency index. Funnel plots and Egger's regression intercept test were used to address the publication bias.

RESULTS

Thirteen studies that satisfied the search criteria were selected for meta-analysis. The studies identified in our study included 353 SRS and 511 hSRS-treated patients. Analysis of heterogeneity showed that hSRS is employed for relatively larger tumor sizes in comparison to SRS. Pooled meta-analysis estimates showed no significant differences between SRS and hSRS in terms of tumor control (odds ratio [OR], 0.620; 95% confidence interval [CI], 0.21-1.86, P = 0.39), hearing preservation (OR, 1.07; 95% CI, 0.59-1.93, P = 0.83), facial nerve preservation (OR, 0.53; 5% CI, 0.23-1.21, P = 0.13), or trigeminal nerve preservation (OR, 0.67; 95% CI, 0.24-1.89, P = 0.49) at a mean follow-up of 39 months. Statistically significant heterogeneity was found across the studies only for tumor diameter (Higgins's inconsistency index = 65.69%, P = 0.003) but not for other variables.

CONCLUSIONS

Meta-analysis of thirteen studies comparing SRS and hSRS as treatment for VS showed comparable tumor control, hearing preservation, facial nerve preservation, and trigeminal nerve preservation.

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.

Characteristics and Management of Facial Nerve Schwannomas and Hemangiomas

OBJECTIVES

To characterize facial nerve (FN) schwannomas (FNSs) and FN hemangiomas (FNHs) and their clinical features and management strategies, and to describe the results of cable nerve grafting after FN sectioning during tumor removal.

METHODS

This retrospective study included 84 FNS cases and 42 FNH cases managed between July 1989 and July 2020 at a quaternary referral center for skull base pathology. Clinical details, locations, management, and results of cable nerve grafting at 1 year and during an average period of 3.12 years were evaluated. Sural nerve interpositioning was performed for patients who experienced FN paralysis for less than 1 year and underwent nerve sectioning during tumor removal.

RESULTS

FNSs more often involved multiple segments compared with FNHs. The cerebellopontine angle and the mastoid segments were involved in 16 (19.1%) and 34 (40.5%) FNS cases, respectively; however, the cerebellopontine angle and the mastoid segments were involved in 0 and 7 (16.7%) FNH cases, respectively. Sectioned nerves of 99 patients (78.6%) were restored using interposition cable grafting. At the last follow-up evaluation, 56.3% of FNSs and 60.7% of FNHs attained House-Brackmann (HB) grade III. Lower preoperative HB grades were associated with poorer postoperative outcomes. For FNSs, the mean HB grades were 4.13 at 1 year postoperatively and 3.75 at the last follow-up evaluation ( p = 0.001); however, for FNHs, the mean HB grades were 4.04 postoperatively and 3.75 at the last follow-up evaluation. Therefore, extradural coaptation yielded better outcomes.

CONCLUSION

FNSs can occur along any part of the FN along its course, and FNHs are concentrated around the area of geniculate ganglion. The results of cable inter positioning grafts are better in patients with preoperative FN-HB-III or less when compared with higher grades. The outcome of the interpositioning continues to improve even after 1 year in extradural coaptation.

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.

Strategy for dealing with unfamiliar and thick vessels during microvascular decompression: A first case report of hemifacial spasm caused by a persistent primitive trigeminal artery

RATIONALE

A persistent primitive trigeminal artery (PPTA) is a rare embryonic cerebrovascular anomaly. Hemifacial spasm (HFS) refers to involuntary contractions of facial muscles caused by the compression of blood vessels against the root exit zone of the facial nerve. There have been no reported cases of PPTA causing neurovascular contact and HFS. Microvascular decompression surgery effectively treats HFS, but operating on strong PPTA vessels poses challenges. We aim to introduce a more efficient approach for overcomes these difficulties and facilitates surgery.

PATIENT CONCERNS

A 44-year-old male patient without any underlying medical conditions presented to our hospital with involuntary movements of the left side of his face accompanied by numbness in the left maxilla (V2 area).

DIAGNOSIS

Brain magnetic resonance imaging and magnetic resonance angiography showed that PPTA was in contact with the left facial nerve.

INTERVENTIONS AND OUTCOMES

Following a retro-sigmoid craniotomy, we attempted to interpose the facial nerve and the PPTA as an offender vessel, but the decompression was not sufficient. However, after transposing the vessel using the proximal Teflon transposition with interposition technique, the strength of the involuntary movements was reduced. Following surgery, there was no more lateral spreading response, and the patient symptoms improved.

LESSIONS

In cases where the vessel causing HFS is particularly strong and thick, the proximal Teflon transposition with interposition technique for transposition may be advantageous. This method could simplify and enhance the efficacy of microvascular decompression, without compromising the quality of surgical outcomes.

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.

Diffusion MRI of the facial-vestibulocochlear nerve complex: a prospective clinical validation study

OBJECTIVES

Surgical planning of vestibular schwannoma surgery would benefit greatly from a robust method of delineating the facial-vestibulocochlear nerve complex with respect to the tumour. This study aimed to optimise a multi-shell readout-segmented diffusion-weighted imaging (rs-DWI) protocol and develop a novel post-processing pipeline to delineate the facial-vestibulocochlear complex within the skull base region, evaluating its accuracy intraoperatively using neuronavigation and tracked electrophysiological recordings.

METHODS

In a prospective study of five healthy volunteers and five patients who underwent vestibular schwannoma surgery, rs-DWI was performed and colour tissue maps (CTM) and probabilistic tractography of the cranial nerves were generated. In patients, the average symmetric surface distance (ASSD) and 95% Hausdorff distance (HD-95) were calculated with reference to the neuroradiologist-approved facial nerve segmentation. The accuracy of patient results was assessed intraoperatively using neuronavigation and tracked electrophysiological recordings.

RESULTS

Using CTM alone, the facial-vestibulocochlear complex of healthy volunteer subjects was visualised on 9/10 sides. CTM were generated in all 5 patients with vestibular schwannoma enabling the facial nerve to be accurately identified preoperatively. The mean ASSD between the annotators' two segmentations was 1.11 mm (SD 0.40) and the mean HD-95 was 4.62 mm (SD 1.78). The median distance from the nerve segmentation to a positive stimulation point was 1.21 mm (IQR 0.81-3.27 mm) and 2.03 mm (IQR 0.99-3.84 mm) for the two annotators, respectively.

CONCLUSIONS

rs-DWI may be used to acquire dMRI data of the cranial nerves within the posterior fossa.

CLINICAL RELEVANCE STATEMENT

Readout-segmented diffusion-weighted imaging and colour tissue mapping provide 1-2 mm spatially accurate imaging of the facial-vestibulocochlear nerve complex, enabling accurate preoperative localisation of the facial nerve. This study evaluated the technique in 5 healthy volunteers and 5 patients with vestibular schwannoma.

KEY POINTS

• Readout-segmented diffusion-weighted imaging (rs-DWI) with colour tissue mapping (CTM) visualised the facial-vestibulocochlear nerve complex on 9/10 sides in 5 healthy volunteer subjects. • Using rs-DWI and CTM, the facial nerve was visualised in all 5 patients with vestibular schwannoma and within 1.21-2.03 mm of the nerve's true intraoperative location. • Reproducible results were obtained on different scanners.

A severe headache due to pigmented villonodular synovitis in a rare location: facial nerve on temporomandibular joint. A case report

BACKGROUND

Pigmented villonodular synovitis (PVNS) is an infrequent benign tumor-like proliferative lesion developing from the synovial membranes of the joint, tendon sheath, and bursa.

CLINICAL PRESENTATION

A 44-year-old woman with numbness on the right side of her face, severe headaches, and swelling in temporomandibular region is presented. On head and neck magnetic resonance imaging, an encapsulated mass approximately 2 cm was detected. The fine-needle aspiration biopsy resulted as suspicion of mesenchymal tumor. A complete resection with the capsule was performed over the temporal branch by monitoring of the facial nerve. The final histopathologic examination resulted as a giant cell tendon sheath tumor.

CONCLUSION

Headache is not the main symptom in PVNS, but in severe pain spreading from the temporomandibular region, physical examination should be done carefully for slight swelling, and the possibility of pigmented villonodular synovitis should be considered. Because of the high recurrence rate, en bloc resection is necessary.

SGMS2 in primary osteoporosis with facial nerve palsy

Pathogenic heterozygous variants in SGMS2 cause a rare monogenic form of osteoporosis known as calvarial doughnut lesions with bone fragility (CDL). The clinical presentations of SGMS2-related bone pathology range from childhood-onset osteoporosis with low bone mineral density and sclerotic doughnut-shaped lesions in the skull to a severe spondylometaphyseal dysplasia with neonatal fractures, long-bone deformities, and short stature. In addition, neurological manifestations occur in some patients. SGMS2 encodes sphingomyelin synthase 2 (SMS2), an enzyme involved in the production of sphingomyelin (SM). This review describes the biochemical structure of SM, SM metabolism, and their molecular actions in skeletal and neural tissue. We postulate how disrupted SM gradient can influence bone formation and how animal models may facilitate a better understanding of SGMS2-related osteoporosis.

Intraoperative diagnosis of facial schwannomas: a multicenter summation of clinical experience, preoperative avoidance, and intraoperative management protocol

OBJECTIVE

Preoperative differentiation of facial nerve schwannoma (FNS) from vestibular schwannoma (VS) can be challenging, and failure to differentiate between these two pathologies can result in potentially avoidable facial nerve injury. This study presents the combined experience of two high-volume centers in the management of intraoperatively diagnosed FNSs. The authors highlight clinical and imaging features that can distinguish FNS from VS and provide an algorithm to help manage intraoperatively diagnosed FNS.

METHODS

Operative records of 1484 presumed sporadic VS resections between January 2012 and December 2021 were reviewed, and patients with intraoperatively diagnosed FNSs were identified. Clinical data and preoperative imaging were retrospectively reviewed for features suggestive of FNS, and factors associated with good postoperative facial nerve function (House-Brackmann [HB] grade ≤ 2) were identified. A preoperative imaging protocol for suspected VS and recommendations for surgical decision-making following an intraoperative FNS diagnosis were created.

RESULTS

Nineteen patients (1.3%) with FNSs were identified. All patients had normal facial motor function preoperatively. In 12 patients (63%), preoperative imaging demonstrated no features suggestive of FNS, with the remainder showing subtle enhancement of the geniculate/labyrinthine facial segment, widening/erosion of the fallopian canal, or multiple tumor nodules in retrospect. Eleven (57.9%) of the 19 patients underwent a retrosigmoid craniotomy, and in the remaining patients, a translabyrinthine (n = 6) or transotic (n = 2) approach was used. Following FNS diagnosis, 6 (32%) of the tumors underwent gross-total resection (GTR) and cable nerve grafting, 6 (32%) underwent subtotal resection (STR) and bony decompression of the meatal facial nerve segment, and 7 (36%) underwent bony decompression only. All patients undergoing subtotal debulking or bony decompression exhibited normal postoperative facial function (HB grade I). At the last clinical follow-up, patients who underwent GTR with a facial nerve graft had HB grade III (3 of 6 patients) or IV facial function. Tumor recurrence/regrowth occurred in 3 patients (16%), all of whom had been treated with either bony decompression or STR.

CONCLUSIONS

Intraoperative diagnosis of an FNS during a presumed VS resection is rare, but its incidence can be reduced further by maintaining a high index of suspicion and undertaking further imaging in patients with atypical clinical or imaging features. If an intraoperative diagnosis does occur, conservative surgical management with bony decompression of the facial nerve only is recommended, unless there is significant mass effect on surrounding structures.

A Large Intratemporal Facial Nerve Schwannoma Presenting as an Occluding External Auditory Canal Mass

Facial nerve schwannomas are rare, benign, slow-growing tumors that can occur in any segment of the facial nerve, although 71% of cases are intratemporal. Surgical resection can lead to facial nerve injury. Facial function recovery after reanimation is usually not better than House-Brackmann (HB) grade III. Thus, for cases of intratemporal facial nerve schwannomas (IFNSs) with favorable facial function (HB grade I or II), observation by periodic magnetic resonance imaging is the mainstay of management. Here, we present a case of a large IFNS with normal facial function in which the mass fully occluded the external auditory canal. The occlusion caused squamous debris to accumulate, potentially leading to cholesteatoma. Faced with this therapeutic dilemma, we chose surgical resection with the patient's informed consent. Stripping surgery was achieved with normal postoperative facial function. There was no postoperative facial paralysis or recurrence at 2-year follow-up. We describe the experience of diagnosis and treatment process for this case, and discuss the possibility of total resection of the tumor with preserving the integrity of facial nerve.

Identification of Degenerated Murine Facial Nerves With Fluorescence Labeling After Transection Injury

OBJECTIVE

Delayed peripheral nerve repair is complicated by nerve degeneration and atrophy that can prevent identification. We use a murine facial nerve transection model to demonstrate the efficacy of ALM-488 (bevonescein) in labeling degenerated facial nerves with quantitative image analysis and qualitative survey data.

STUDY DESIGN

Prospective cohort study.

SETTING

Laboratory.

METHODS

Ten wild-type mice underwent transection of the lower facial nerve division with subsequent degeneration. Either 9 (n = 5 mice) or 12 (n = 5 mice) weeks later, mice underwent intravenous infusion of ALM-488 with in vivo real-time fluorescence imaging (FL) of the facial nerve. Using ImageJ, the mean gray value of each nerve segment under white light reflectance (WLR) and FL was compared to that of adjacent soft tissue to calculate the signal-to-background ratio (SBR). A survey was distributed to evaluate the perceived utility of ALM-488 in surgeon identification of degenerated nerves.

RESULTS

The mean SBR of degenerated nerves was 1.08 (standard deviation [SD]: 0.07) under WLR and 2.11 (SD: 0.31) under FL (p < 0.001). In mice with degenerated nerves, survey participants identified on average 3.01 (SD: 1.84) nerve branches under WLR and 5.73 (SD: 1.88) under FL (p < 0.0001). Under FL, 47 of 48 survey responses correctly identified isolated, degenerated nerves; in contrast, only 12 responses identified degenerated nerves under WLR (p < 0.0001).

CONCLUSION

Preoperative intravenous infusion of ALM-488 with FL improves the identification of degenerated facial nerves. ALM-488 also improves surgeon confidence in nerve identification, particularly in degenerated nerve branches that are not visible with WLR.

Proton beam radiation therapy for vestibular schwannomas-tumor control and hearing preservation rates: a systematic review and meta-analysis

OBJECTIVE

Proton beam therapy is considered, by some authors, as having the advantage of delivering dose distributions more conformal to target compared with stereotactic radiosurgery (SRS). Here, we performed a systematic review and meta-analysis of proton beam for VSs, evaluating tumor control and cranial nerve preservation rates, particularly with regard to facial and hearing preservation.

METHODS

We reviewed, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) articles published between 1968 and September 30, 2022. We retained 8 studies reporting 587 patients.

RESULTS

Overall rate of tumor control (both stability and decrease in volume) was 95.4% (range 93.5-97.2%, p heterogeneity= 0.77, p<0.001). Overall rate of tumor progression was 4.6% (range 2.8-6.5%, p heterogeneity < 0.77, p<0.001). Overall rate of trigeminal nerve preservation (absence of numbness) was 95.6% (range 93.5-97.7%, I2 = 11.44%, p heterogeneity= 0.34, p<0.001). Overall rate of facial nerve preservation was 93.7% (range 89.6-97.7%, I2 = 76.27%, p heterogeneity<0.001, p<0.001). Overall rate of hearing preservation was 40.6% (range 29.4-51.8%, I2 = 43.36%, p heterogeneity= 0.1, p<0.001).

CONCLUSION

Proton beam therapy for VSs achieves high tumor control rates, as high as 95.4%. Facial rate preservation overall rates are 93%, which is lower compared to the most SRS series. Compared with most currently reported SRS techniques, proton beam radiation therapy for VSs does not offer an advantage for facial and hearing preservation compared to most of the currently reported SRS series.

Clinical outcomes and safety of large or giant vestibular schwannoma in older patients undergoing microsurgery: a matched cohort study

OBJECTIVE

To compare the clinical outcomes of large or giant vestibular schwannomas (VSs) between older patients and younger patients who underwent microsurgery and to explore whether the incidence of postoperative complications increased and whether the postoperative hospital stay was prolonged.

METHODS

We conducted a retrospective matched cohort study based on the surgical approach, maximum tumor diameter and extent of resection. Older patients (≥ 60 years) and a matched group (<60 years) who had undergone microsurgery for VSs between January 2015 and December 2021 were included. Clinical data, surgical outcomes and postoperative complications were analyzed statistically.

RESULTS

Forty-two older patients (≥ 60 years, 66.0 ± 3.8 years) were identified and matched to younger patients (<60 years, 43.9 ± 11.2 years), and they all underwent microsurgery through a retrosigmoid approach. There were twenty-nine patients with 3-4 cm VSs and thirteen patients with > 4 cm VSs in both groups. The older patients had a higher proportion of imbalance (P = 0.016) and lower American Society of Anesthesiology scores (P = 0.003) before surgery than the younger patients. There was no significant difference in facial nerve function one week (p = 0.851) and one year (p = 0.756) after surgery and no difference in the postoperative complication incidence (40.5% vs. 23.8%, p = 0.102) between the older patients and controls. Furthermore, the older patients had longer postoperative hospital stays than the younger patients (p = 0.043). In the older group, six patients with near total resection and five with subtotal resection were administered stereotactic radiotherapy, and one had recurrence three years after surgery and received conservative treatment. The postoperative follow-up time ranged from 1 to 83 months, with an average of 33.5 ± 21.1 months.

CONCLUSIONS

For older patients (≥ 60 years) with symptomatic, large or giant -VSs, microsurgery is the only effective method to prolong lifespan, alleviate clinical symptoms and cure the tumor. However, radical resection of VSs may result in a decreased preservation rate of facial-acoustic nerve function and an increased postoperative complication incidence. Therefore, subtotal resection followed by stereotactic radiotherapy should be recommended.

Dosimetric predictive factors for facial nerve paralysis after cyberknife® stereotactic radiotherapy for vestibular schwannomas: A single institution experience of 88 patients

PURPOSE

To identify dosimetric predictive factors of facial nerve paralysis for patients with vestibular schwannomas (VS) treated in a single institution with Cyberknife® (CK) hypofractionated stereotactic radiotherapy (SRT).

METHODS AND MATERIALS

Eighty-eight patients were treated from 2010 to 2020. Different treatment schedules were used over that period, some prescribed to the 80% isodose line (4 × 5 Gy, 3 × 7 Gy, 3 × 8 Gy and 5 × 5 Gy) and one to the 70% isodose line (3 × 7.7 Gy). Local control tumor and facial nerve toxicity were recorded, as well as various dosimetric indicators.

RESULTS

Median follow-up 37 months (range, 7-96). Of the 88 stereotactic treatments, 20 patients (23%) developed objectively diagnosed radiation-induced facial nerve paralysis. The 2-year and 5-year local tumor control were respectively 95% and 88%, and the overall 2-year facial nerve preservation was 76%. Prescriptions with a maximum dose point (Dmax) of 33 Gy were at a substantially higher risk of facial paralysis than prescriptions with a Dmax less than or equal to 30 Gy (HR = 4.51, 95% CI = [1.04;19.6], p = 0.045). The 2-years cumulative incidences of facial paralysis were 32% [20%;44%] in the case of a 33 Gy Dmax, against 7% [1%;21%] otherwise. We identified four significative dosimetric predictive factors for radiation-induced facial nerve dysfunction: a GTV minimal dose over 22 Gy (EQD2 = 45.5 Gy, p = 0.019), a GTV mean dose over 29 Gy (EQD2 = 73.5 Gy, HR = 2.84, 95% CI = [1.10;7.36], p = 0.024), a PTV mean dose over 27 Gy (EQD2 = 64.8 Gy, HR = 10.52, 95% CI = [1.39;79.76], p = 0.002) and a PTV maximal dose of 32 Gy (EQD2 = 87.5 Gy,HR = 5.09, 95% CI = [1.17;22.15], p = 0.013).

CONCLUSION

We identified four dosimetric predictive factors for post-treatment facial paralysis. Increasing the doses of hypofractionated stereotactic radiotherapy for vestibular schwannomas leads to higher facial nerve toxicity and may lead to lower local control rates than other published series. Our three-hypofractionated regimens may have also played a role in these results.

Prospective Assessment of Risk Factors Influencing Facial Nerve Paresis in Patients after Surgery for Parotid Gland Tumors

Background and objectives: Facial weakness is the most important complication of parotid gland tumor surgery. The aims of this study are as follows: (1) assessment of the prevalence of postparotidectomy facial nerve dysfunction; (2) clinical and electrophysiological assessment of the facial nerve function before parotidectomy and at 1 and 6 months postoperatively; (3) assessment of the association of postoperative facial palsy with selected risk factors; and (4) assessment of the correlation between the results of clinical and neurophysiological assessments of facial nerve function. Materials and Methods: This study comprised 50 patients (aged 24-75 years) who underwent parotidectomy at the Department of Otolaryngology and Laryngological Oncology in Zabrze, Poland between 2015 and 2017. The evaluation included neurological, clinical and electrophysiological assessments of the facial nerve prior to surgery and at 1 and 6 months postoperatively. Results: No facial palsy was found preoperatively or 6 months postoperatively. Facial nerve dysfunction was found in 74% of patients 1 month postoperatively. In most cases (54%), paresis was mild or moderate (House-Brackmann grades II and III). The results of electrophysiological tests before parotidectomy were either normal or showed some mild abnormalities. We found a statistically significant correlation between the clinical assessment of the facial nerve function (based on the House-Brackmann scale) one month postoperatively and the latency of the CMAP response from the orbicularis oculi and orbicularis oris muscles. In all three studies, a statistically significant correlation was found between the amplitude of the compound muscle action potential (CMAP) of the orbicularis oris muscle and the degree of facial nerve weakness. Conclusions: The factors that may influence the risk of postoperative facial nerve paralysis (prolonged surgical time and the size and location of the tumor other than in the superficial lobe only) may indirectly suggest that surgery-related difficulties and/or surgeon experience could be crucial to surgery safety.

Simultaneous Occurrence of Chicken Pox and Herpes Zoster with Facial Nerve Palsy in Immunocompetent Patient

Patients who earlier suffered from chicken pox may develop herpes zoster (HZ) due to reactivation in dorsal root ganglia. The occurrence of both clinical conditions at the same time is sporadic. Unusual presentation and a belligerent course are seen in immunocompromised hosts. The presence of both HZ and chicken pox in immunocompetent patients is infrequent and incoherent with the present understanding of pathogenesis. Here, we present a case of HZ involving the maxillary division of the right trigeminal nerve with simultaneous occurrence of varicella-zoster and right peripheral facial nerve palsy.

Optimal Volume of the Residual Tumor to Predict Long-term Tumor Control Using Stereotactic Radiosurgery after Facial Nerve-preserving Surgery for Vestibular Schwannomas

BACKGROUND

Intended subtotal resection (STR) followed by adjuvant gamma knife radiosurgery (GKRS) has emerged as an effective treatment option for facial nerve (FN) preservation in vestibular schwannomas (VSs). This study aimed to identify the optimal cut-off volume of residual VS to predict favorable outcomes in terms of both tumor control and FN preservation.

METHODS

This retrospective study assessed the patients who underwent adjuvant GKRS for residual VS after microsurgery. A total of 68 patients who had been followed up for ≥ 24 months after GKRS were included. Tumor progression was defined as an increase in tumor volume (TV) of ≥ 20%. House-Brackmann grades I and II were considered to indicate good FN function.

RESULTS

The median residual TV was 2.5 cm³ (range: 0.3-27.4). The median follow-up period after the first adjuvant GKRS was 64 months (range: 25.7-152.4). Eight (12%) patients showed tumor progression. In multivariate analyses, residual TV was associated with tumor progression (P = 0.003; hazard ratio [HR], 1.229; 95% confidence interval [CI], 1.075-1.405). A residual TV of 6.4 cm³ was identified as the cut-off volume for showing the greatest difference in progression-free survival (PFS). The 5-year PFS rates in the group with residual TVs of < 6.4 cm³ (54 patients) and that with residual TVs of ≥ 6.4 cm³ (14 patients) were 93.3% and 69.3%, respectively (P = 0.014). A good FN outcome was achieved in 57 (84%) patients. Residual TV was not associated with good FN function during the immediate postoperative period (P = 0.695; odds ratio [OR], 1.024; 95% CI, 0.908-1.156) or at the last follow-up (P = 0.755; OR, 0.980; 95% CI, 0.866-1.110).

CONCLUSION

In this study, residual TV was associated with tumor progression in VS after adjuvant GKRS following STR. As preservation of FN function is not correlated with the extent of resection, optimal volume reduction is imperative to achieve long-term tumor control. Our findings will help surgeons predict the prognosis of residual VS after FN-preserving surgery.

The effect of insulin-like growth factor 1 on the recovery of facial nerve function in a guinea pig model of facial palsy

The efficacy of insulin-like growth factor 1 (IGF-1) in the treatment of peripheral facial nerve palsy was investigated using an animal model. The facial nerve within the temporal bone was exposed and compressed by clamping. The animals were treated with either IGF-1 or saline which was topically administered by a gelatin-based sustained-release hydrogel via an intratemporal route. The recovery from facial nerve palsy was evaluated at 8 weeks postoperatively based on eyelid closure, complete recovery rate, electroneurography and number of axons found on the facial nerve. IGF-1 treatment resulted in significant improvement in the changes of the degree of eyelid closure over the total time period and complete recovery rate. A separate study showed that IGF-1 receptor mRNA was expressed in facial nerves up to 14 days after the nerve-clamping procedure. IGF-1 was thus found to be effective in the treatment of peripheral facial nerve palsy when topically applied using a sustained-release gelatin-based hydrogel via an intratemporal route.

Histological characteristics of intra-temporal facial nerve paralysis in temporal bone malignancies

OBJECTIVE

To describe the histopathologic findings and clinical presentation of intra-temporal facial nerve invasion in primary and metastatic malignancies of the human temporal bone (TB).

MATERIALS AND METHODS

Retrospective analysis of all medical records of patients diagnosed with peripheral facial nerve palsy (PFnP) of a malignant origin was performed. Temporal bones underwent standard processing for histologic examination. Hematoxylin and eosin (H&E)-stained slides were examined by light microscopy. The histologic findings were compared to premortem clinical data.

RESULTS

Eighteen TBs were identified in 16 patients. The male to female ratio was 9:7. The median (range) age of death was 56.5 years (27 months to 75 years). The median time interval from facial nerve injury to death was 5.5 months. There were 11 carcinomas and seven sarcomas identified. Primary TB malignancies were identified in seven TBs (39%), and the rest (11 TBs, 61%) were of metastatic origin. Complete facial nerve paralysis (House-Brackmann [HB] grade VI), was the most common clinical presentation affecting nine patients (10 TBs, 56%). Neural involvement was multifocal in nature (16 of 18 TBs, 89%). The most commonly involved cranial nerve (CN) VII segment was the meatal segment (13 TBs, 72%), followed by the labyrinthine, tympanic, and vertical segments (nine, eight, and six TBs, respectively).

CONCLUSION

PFnP can be the result of local, regional, or distant malignancy, and is associated with poor survival. The facial nerve can serve as a route of tumor progression intracranially. Whereas every segment of CNV II can be violated by tumors, not all PFnP are related to direct tumor invasion.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:E358-E367, 2020.

Vestibular Impairment in Hemifacial Spasm Syndrome: A Case Report

A 52-year-old man presented with left hemifacial spasm (HFS). A magnetic resonance imaging scan showed compression of the left facial nerve at the cerebellopontine angle by a dolichoectatic basilar artery. The neurotological evaluation showed an otolithic deficit, with canalicular preservation and normal hearing. The deficit improved after surgical decompression. No previous report has described the impairment of vestibular function in patients presenting with HFS.

Arachnoid bands and venous compression as rare causes of hemifacial spasm: analysis of etiology in 353 patients

BACKGROUND

Hemifacial spasm is usually caused by arterial compression at the root exit zone of the facial nerve. However, other etiologies have been reported. The aim of this study was to analyze the frequency of other causes of hemifacial spasm.

METHODS

Our prospectively maintained hemifacial spasm database containing all patients who underwent microvascular decompression (MVD) for hemifacial spasm from 2002 to 2018 was reviewed. All offending structures were identified and recorded by the surgeon at the time of surgery. Additionally, the operative videos were analyzed retrospectively.

RESULTS

MVD was performed in 353 patients. Arterial compression was the main cause of hemifacial spasm in 341 (96.9%) patients. Combined venous-arterial compression was seen in 7 (2.0%) patients. In one patient, the compression was from a large vein. In two patients, no compression was found. One patient who suffered from Bell's palsy many years previously had severe synkinesis and the other had facial tics. In two patients, the spasm was caused due to strangulation of the facial nerve by arachnoid bands. Long-term follow-up of more than 18 months was available in 249 patients with total resolution or near total resolution of spasms in 89.96% of patients.

CONCLUSIONS

In most patients with hemifacial spasm, arterial vessels are involved in compressing the facial nerve. Purely venous compression is rarely encountered. We report for the very first time arachnoid bands strangulating the nerve as a cause for hemifacial spasm without involvement of any vessel.

Rat Facial Nerve Regeneration with Human Immature Dental Pulp Stem Cells

Facial paralysis can result in severe implications for the patients. However, stem cell biology has become an important field in regenerative medicine since the discovery and characterization of mesenchymal stem cells. Our aim was to evaluate the regeneration after facial nerve crush injury and application of human immature dental pulp stem cells (iDPSC). For this study 70 Wistar rats underwent a unilateral facial nerve crush injury and were divided into two groups: Group I (GI): Crushed; Group II (GII): Crushed and iDPSC, and distributed into study periods of 3, 7, 14, 21, and 42 postoperative days. Facial nerve regeneration was analyzed via functional recovery of whisker movement, histomorphometric analysis, and immunoblotting assay. The results show that GII had complete functional recovery at 14 days, while GI recovered after 42 days. Also, regarding the facial nerve trunk, GII presented histological improvement, evidencing better axonal and structural organization of the myelin sheath, and exhibited statistically higher values for the outer and inner perimeters and g-ratio. Nevertheless, GI exhibited statistically higher values for the thickness of myelin sheath. In the buccal branch, no differences were observed for all parameters between groups. At 42 days, both groups GI and GII were close to the levels observed for the control group. Concerning nerve growth factor expression, GII exhibited statistically greater values (p < 0.05) compared with the control group at 7 days. In summary, a single injection of human iDPSC promoted a positive effect on regeneration of the facial nerve trunk after 14 days and provided an alternative to support regeneration following peripheral nerve injury.

Facial nerve schwannoma mimicking chronic suppurative otitis media: A case report

RATIONALE

Facial nerve schwannoma (FNS) is a rare slow-growing nerve sheath tumor derived from Schwann cells. FNS with normal facial nerve function may sometimes be misdiagnosed as otitis media because of similar ontological symptoms such as purulence, tympanic membrane damage, and hearing loss.

PATIENT CONCERNS

A 68-year-old woman was referred to our department because of otorrhea and hearing loss in the right ear for 20 years. Otoscopy revealed abundant purulent secretions deep in the right external auditory canal, and granulation proliferation in the posterior part of membranae tensa. Audiogram showed a right mixed hearing loss with an 85-dB pure-tone average and 35-dB air-bone gap.

DIAGNOSIS

This patient was misdiagnosed as chronic suppurative otitis media before surgery. During surgery, a mass was found, and intraoperative frozen section histopathology confirmed an FNS.

INTERVENTIONS

This patient was subjected to mastoidectomy for curing chronic suppurative otitis media initially. During surgery, a mass was found attached and widely extended into the tympanic and mastoid segments. We removed most part of the mass, however found the mass deriving from the vertical part of the facial nerve. Intraoperative frozen section histopathology confirmed an FNS. So we removed the incurs and malleus, and searched for the edge of the mass. The mass involved multisegments of facial nerve including the tympanic, vertical and pyramidal segments. The tumor was removed completely, and nerves were repaired using greater auricular nerves.

OUTCOMES

After surgery, the patient had facial nerve paralysis of House-Brackmann (HB) Grade VI. Facial function recovered to HB Grade III at 30 months after surgery. The patient was followed up for 5 years. She had a facial function of HB grade III at the most recent follow-up.

LESSONS

FNS is rare and tend to be misdiagnosed. It is important to combine the imaging modalities of computed tomography and magnetic resonance imaging to evaluate FNS before surgery. The primary goal of managing FNS is to maintain normal facial function as long as possible; therefore, tailored strategy should be taken for managing FNS.

Chordoma located in the jugular foramen: Case report

RATIONALE

Chordomas are rare malignant neoplasms arised from residual embryonic notochordal tissue, mostly located in the axial midline. Tumors along extra-axial locations in the head and neck are rare. Chordomas located in the jugular foramen are extremely rare, with a low incidence of 0.2%.

PATIENT CONCERNS

A 64-year-old male with 20 years of dizziness history complaining of 6 months of severe dizziness: significant with the changing of the body posture, vertigo which can be self-remissioned within 1 minute and hearing loss of both ears, without headache, nausea, dysphagia, or otalgia. Computed tomography and magnetic resonance imaging (MRI) were performed before surgery which suggests various possibilities. Immunohistochemistry helped to confirm the final diagnosis.

DIAGNOSES

Immunohistochemistry demonstrated diffuse positivity for S100 (+++), positivity for D2-40 (focal +), EMA (+), and PR (+). Ki-67 labeling index was estimated at 2% focally. The final diagnosis was chordoma.

INTERVENTIONS

The tumor was excised via retro-sigmoid approach without postoperative radiotherapy.

OUTCOMES

Facial paralysis occurred in this case. House-Brackmann facial nerve grading system was used to evaluate the facial paralysis of this patient. It is considered as H-B grade IV. The patient was followed up regularly every month after operation, totally for 9 months. An MRI of the brain was performed 6 months after surgery which shows a small range of abnormal signals similar to the previous MRI in the jugular foramen, suggesting that there may be residual or recurrent tumor. And facial paralysis stays at H-B grade IV without any recovery.

LESSONS

It is a big challenge for us to remove giant tumors located in the jugular foramen because of its unique anatomy. Access should be combined with retro-sigmoid or infra-temporal fossa approach to remove such tumors. Chordomas is a malignant neoplasm which may need radiotherapy after surgery, particularly those with subtotal and partial resection.

Granular cell tumor of the trunk of the facial nerve: A case report

RATIONALE

Granular cell tumor (GCT) is a relatively uncommon, usually benign lesion that often presents as a solitary, painless cutaneous or submucosal nodule. GCTs of the head and neck are not uncommon; however, involvement of the trunk of the facial nerve is rare.

PATIENT CONCERNS

A 55-year-old woman presented a lesion at the posterior border of the left parotid gland. Doppler ultrasound revealed a hypoechoic mass and magnetic resonance imaging disclosed an irregularly shaped lesion with unsharp borders in the posterior aspect of the left parotid gland that was hyperintense on T2-weighted images and enhancing with contrast on T1-weighted images. The remainder of the parotid gland was normal.

DIAGNOSIS

Following excision of the mass, diagnosis of a GCT was established and confirmed by immunohistochemistry.

INTERVENTIONS

The patient underwent surgical excision of the lesion.

OUTCOMES

The patient is currently asymptomatic and without recurrence after 10 months follow-up.

LESSONS

GCT involvement of the trunk of the facial nerve is rare. Immunohistochemical staining is helpful for its diagnosis.

Management of the facial nerve in parotid cancer: preservation or resection and reconstruction

PURPOSE

Management of the facial nerve is instrumental in the surgical treatment of parotid cancer.

METHODS

A literature search was conducted using PubMed and ScienceDirect database. A total of 195 articles were finally included into the analysis, based on relevance, scientific evidence and actuality.

RESULTS

In the majority of cases the facial nerve is not involved by tumor. In these cases, identification and preservation of the nerve, in addition to complete tumor removal, are essential for successful surgery. When the nerve is infiltrated by tumor, the affected portion of the nerve must be resected as part of radical parotidectomy. Primary nerve reconstruction or other reanimation techniques give the best long-term functional and cosmetic results. A comprehensive diagnostic evaluation with current imaging and electrophysiological studies will provide the surgeon with the best knowledge of the relationship of the facial nerve to the tumor. Several standardized methods are helpful in finding, dissecting and preserving the nerve during parotid cancer surgery. When radical parotidectomy is indicated, the initial diagnostic work-up can assist in defining the need for adjuvant postoperative therapy and facial reanimation. The aim of rehabilitation is to restore tone, symmetry, and movement to the paralyzed face.

CONCLUSIONS

The surgical management of facial paralysis has undergone many improvements in recent years. This review gives an overview of recent advances in the diagnostic work-up, surgical techniques and any necessary rehabilitation of the facial nerve in parotid cancer surgery.

Primary Central Nervous System Post-transplant Lymphoproliferative Disorder Diagnosed by Peripheral Facial Nerve Palsy

Although primary central nervous system post-transplant lymphoproliferative disorder (PCNS-PTLD) causes various symptoms depending on the tumor region, there has been no previous report of PCNS-PTLD in the cerebellopontine angle that was diagnosed due to peripheral facial nerve palsy. We herein report a case involving a 62-year-old man with PCNS-PTLD in the cerebellopontine angle who was diagnosed due to peripheral facial nerve palsy. The reduction of immunosuppressive therapy, whole-brain radiotherapy, intrathecal chemotherapy, and rituximab were effective in treating this patient. Physicians should therefore be mindful that PCNS-PTLD can cause peripheral facial nerve palsy in renal transplant recipients.

Upfront Gamma Knife surgery for facial nerve schwannomas: retrospective case series analysis and systematic review

INTRODUCTION

Facial nerve schwannomas are rare tumors and account for less than 2% of intracranial neurinomas, despite being the most common tumors of the facial nerve. The optimal management is currently under debate and includes observation, microsurgical resection, radiosurgery (RS), and fractionated radiotherapy. Radiosurgery might be a valuable alternative, as a minimally invasive technique, in symptomatic patients and/or presenting tumor growth.

METHODS

We review our series of four consecutive cases, treated with Gamma Knife surgery (GKS) between July 2010 and July 2017 in Lausanne University Hospital, Switzerland. Clinical and dosimetric parameters were assessed. Radiosurgery was performed using Leksell Gamma Knife Perfexion. We additionally performed a systematic review, which included 23 articles and 193 treated patients from the current literrature.

RESULTS

The mean age at the time of the GKS was 44.25 years (median 43.5, range 34-56). Mean follow-up period was 31.8 months (median 36, range 3-60). Two cases presented with facial palsy and other two with hemifacial spasm. Pretherapeutically, House-Brackmann (HB) grade was II for one case, III for two, and VI for one. The mean gross tumor volume (GTV) was 0.406 ml (median 0.470 ml, range 0.030-0.638 ml). The mean marginal prescribed dose was 12 Gy at the mean 54% isodose line (median 50%, range 50-70). The mean prescription isodose volume (PIV) was 0.510 ml (median 0.596 ml, range 0.052-0.805 ml). The mean dose received by the cochlea was 4.2 Gy (median 4.1 Gy, range 0.1-10). One patient benefited from a staged-volume GKS. At last follow-up, tumor volume was stable in one and decreased in three cases. Facial palsy remained stable in two patients (one HB II and one HB III) and improved in two (from HB III to II and from HB VI to HB III). Regarding hemifacial spasm, both patients presenting one pretherapeutically had a decrease in its frequency and intensity after GKS. All patients kept stable Gardner-Robertson class 1 at last follow-up.

CONCLUSION

In our experience, RS and particularly GKS, using standard, yet low doses of radiation, appear to be a safe and effective therapeutic option in the management of these rare tumors. The results as from our systematic review are also encouraging with satisfactory rates of clinical stabilization and/or improvement and high rate of tumor control. Complications are infrequent and mostly transient.

Facial Nerve Schwannoma: A Case Report, Radiological Features and Literature Review

Facial nerve schwannoma localized in the middle fossa is a rare lesion. We report a case of a facial nerve schwannoma in a 30-year-old male presenting with facial nerve palsy. Magnetic resonance imaging (MRI) showed a 3 cm diameter tumor of the right middle fossa. The tumor was removed using a sub-temporal approach. Intraoperative monitoring allowed for identification of the facial nerve, so it was not damaged during the surgical excision. Neurological clinical examination at discharge demonstrated moderate facial nerve improvement (Grade III House-Brackmann).

The transotic approach for vestibular schwannoma: indications and results

To analyze retrospectively the indications and the results obtained with the transotic approach in a series of patients with vestibular schwannoma. The study included 36 patients from 2007 to 2013 with a vestibular schwannoma that was removed with a transotic approach. All patients underwent preoperative pure tone audiometry, evaluation of facial function and CT and MR imaging. All patients having (1) a hearing loss of more than 50 dB, (2) an average tumor size of 2.7 cm (range 0.5–5.0 cm) and (3) signs of a contracted mastoid (high jugular bulb, anteriorly located sigmoid sinus, low middle cranial fossa, or reduced pneumatization) were selected. The tumor was totally removed in 34 and near-totally removed in 2 patients. The facial nerve was preserved in all patients. The postoperative facial function after 6 weeks was House–Brackmann grade I in 7, grade II in 27, and grade III in 2 patients. All patients presented postoperatively with unilateral total deafness. Seven patients experienced transitory postoperative imbalance. There were two patients who required revision surgery, one with intracranial hemorrhage and another with a CSF leak. There were no deaths and no severe complications such as hemiplegia or intracranial infections. The transotic approach has proven to be of value for the removal of vestibular schwannomas up to 5.0 cm in the presence of temporal bone contraction. Hearing was not preserved; however, other clinical outcomes were very favorable, including high rates of total tumor removal and facial nerve preservation, and low rates of complications.

A unique case of concomitant intra and extracranial Hansen's disease

Leprosy is a debilitating disease that usually involves the peripheral branches of the cranial nerves leading to anesthetic/hypoesthetic skin lesions and thickened peripheral nerves. However, the involvement of the central nervous system (CNS) is extremely rare. To the best of the author's knowledge, the involvement of the cranial nerve nuclei by leprosy has not been reported in the literature and the present case is the first report of involvement of the facial nerve nuclei by leprosy.

Facilitation of distinct inhibitory synaptic inputs by chemical anoxia in neurons in the oculomotor, facial and hypoglossal motor nuclei of the rat

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the selective loss of motor neurons in the brainstem and spinal cord. Clinical studies have indicated that there is a distinct region-dependent difference in the vulnerability of motor neurons. For example, the motor neurons in the facial and hypoglossal nuclei are more susceptible to neuronal death than those in the oculomotor nucleus. To understand the mechanism underlying the differential susceptibility to cell death of the neurons in different motor nuclei, we compared the effects of chemical anoxia on the membrane currents and postsynaptic currents in different motor nuclei. The membrane currents were recorded from neurons in the oculomotor, facial and hypoglossal nuclei in brain slices of juvenile Wistar rats by using whole-cell recording in the presence of tetrodotoxin that prevents action potential-dependent synaptic transmission. NaCN consistently induced an inward current and a significant increase in the frequency of spontaneous synaptic inputs in neurons from these three nuclei. However, this increase in the synaptic input frequency was abolished by strychnine, a glycine receptor antagonist, but not by picrotoxin in neurons from the hypoglossal and facial nuclei, whereas that in neurons from the oculomotor nucleus was abolished by picrotoxin, but not by strychnine. Blocking ionotropic glutamate receptors did not significantly affect the NaCN-induced release facilitation in any of the three motor nuclei. These results suggest that anoxia selectively facilitates glycine release in the hypoglossal and facial nuclei and GABA release in the oculomotor nucleus. The region-dependent differences in the neurotransmitters involved in the anoxia-triggered release facilitation might provide a basis for the selective vulnerability of motor neurons in the neurodegeneration associated with ALS.

Characteristics of hearing loss in patients with herpes zoster oticus

Patients with herpes zoster oticus (HZO) may commonly show symptoms associated with 7th and 8th cranial nerve (CN VII and CN VIII) dysfunction. The aim of this study is to investigate the characteristics of hearing loss in patients with HZO and discuss possible mechanisms.Ninety-five HZO patients who showed at least one of the symptoms of CN VII and CN VIII dysfunction between January 2007 and October 2014 were included in this study. Hearing loss was defined when the mean thresholds of pure tone audiometry (PTA) in speech frequency (0.5 kHz + 1 kHz + 2 kHz/3) or isolated high frequency (4 kHz + 8 kHz/2) were greater than 10 dB in the affected ear compared with the healthy ear, and a total of 72 patients were classified as the hearing loss group.The difference of mean PTA thresholds between affected and healthy ears was significantly greater in the high frequency range than in low range (20.0 ± 11.5 dB vs. 12.9 ± 15.7 dB, P = 0.0026) in patients with hearing loss (n = 72). The difference between affected and healthy ear was significantly greater in patients with vertigo (n = 34) than those without vertigo (n = 38) in both the high (P = 0.033) and low (P = 0.024) frequency ranges. In contrast, the differences between affected and healthy ears were not significantly different between patients with facial palsy (n = 50) and those without facial palsy (n = 22) in both the high (P = 0.921) and low (P = 0.382) frequency ranges.In patients with HZO, hearing loss is more severe in the high frequency range than in the low frequency range. Hearing impairment is more severe in patients with vertigo than in those without vertigo in both the high and low frequency ranges, even though the degree of hearing impairment is not significantly different between patients with and without facial palsy. These findings indicate that the mechanisms of viral spread from CN VII to CN VIII may differ between vestibular and audiologic deficits.

Neoplastic causes of nonacute facial paralysis: A review of 221 cases

We conducted a retrospective review to assess the clinical presentation of patients with tumor-related nonacute complete peripheral facial weakness or an incomplete partial facial paresis and to provide an algorithm for the evaluation and management of these patients. Our study population was made up of 221 patients-131 females and 90 males, aged 14 to 79 years (mean: 49.7)-who had been referred to the Facial Nerve Disorders Clinic at our tertiary care academic medical center over a 23-year period with a documented neoplastic cause of facial paralysis. In addition to demographic data, we compiled information on clinical signs and symptoms, radiologic and pathologic findings, and surgical approaches. All patients exhibited gradual-onset facial weakness or facial twitching. Imaging identified an extratemporal tumor in 128 patients (58%), an intratemporal lesion in 55 patients (25%), and an intradural mass in 38 (17%). Almost all of the extratemporal tumors (99%) were malignant, while 91% of the intratemporal and intradural tumors were benign. A transtemporal surgical approach was used in the 93 intratemporal and intradural tumor resections, while the 128 extratemporal lesions required a parotidectomy with partial temporal bone dissection. The vast majority of patients (97%) underwent facial reanimation. We conclude that gradual-onset facial paralysis or twitching may occur as a result of a neoplastic invasion of the facial nerve along its course from the cerebellopontine angle to the parotid gland. We caution readers to beware of a diagnosis of "atypical Bell's palsy."

Local Excision Procedure for Warthin's Tumor of the Parotid Gland

The aim of this work is to establish a local excision procedure (LEP) and indications of this procedure for Warthin's tumor. Seventy-three patients (82 sides) with Warthin's tumor were studied. Point I was located 1 cm from the intertragal notch in the direction indicated by the notch. Point S was located 5 mm superior to the inferior end of the mandibular angle. The trunk of the facial nerve and the marginal mandibular branch run at the points I and S, respectively. In surgical maneuvers below the I-S line, the marginal mandibular and colli branches may exist within the surgical field, but the trunk and other peripheral branches of the facial nerve will not be encountered. For Warthin's tumor estimated to be below the I-S line (Group A), LEP was used, involving resection of the tumor after locating and dissecting the marginal mandibular and colli branches. For tumors not meeting these criteria (Group B), partial superficial parotidectomy was performed. Results indicated that mean volume of hemorrhage was significantly smaller, and that mean operation time was significantly shorter in Group A than in Group B. Conversely, no significant difference in tumor size or incidence of postoperative facial paresis was identified between the 2 groups. Recurrence has not yet been noted in either group. In conclusion, LEP is useful for Warthin's tumor below the I-S line. This procedure seems applicable not only to Warthin's tumors, but also to other benign parotid tumors in the surgical field below the I-S line, such as pleomorphic adenoma and lymphoepithelial cyst.

[Bell's palsy in malopolska's children in 2010-2014 years]

BACKGROUND

Peripheral facial nerve palsy (Bell' palsy, BP) is a not rare diseases in children, being the most common acquired mononeuropathy.

AIM

The authors of this study wanted to determine whether the occurrence and course of paralysis changed in the past 5 years (2010-2014).

MATERIALS AND METHODS

The study involved Lesser Poland region, where the majority of children with paralysis are hospitalized at the Pediatric Neurology Department of University Children's Hospital in Krakow. These children in subsequent years were admitted to our department without any limitations. A review of clinical documentation of 125 patients, in terms of demographics, the coexistence of other diseases, seasonality, the degree of paralysis, location of paralysis, the prevalence of the recurrence was made. Changes in the structure of the nerve VII in MRI and CT, pharmacological treatment, applied rehabilitation, the degree of improvement and time of hospitalization were analyzed.

RESULTS

Similar distribution of occurrence and gender of children with BP in Lesser Poland region within 5 years were observed. The predominance of the girls resulted from demographic composition of the population. BP occurred most frequently in summer and winter. In more than half of children BP occurred in the course of acute systemic infection or craniofacial infection and in 5/125 BP followed head injury. Children with infections required antibiotic therapy. Left-sided paralysis was found in the majority of children and almost half of patients needed protection of the cornea of the eye (significant degree). In 12% of children structural changes within the facial nerve were found. In these children antiviral treatment was used and hospitalization time was more than 20 days while in the majority of children hospitalization lasted 15 days. In 8 (6.4%) children with recurrent BP kinezytherapy, electrical stimulation and laser therapy were applied. Steroid therapy was not used. Only 7/125 chil. dren had mild impairment of the eye closing at the discharge and the others received nearly complete recovery.

CONCLUSIONS

Inflammatory etiology is the most common in children with BP. BP occurs more often in the summer and winter. Severity of paralysis was significant in more than half of hospitalized children. Children with structural changes within the nerve VII required longer hospitalization and comprehensive treatment.

Does Laser Surgery Interfere with Optical Nerve Identification in Maxillofacial Hard and Soft Tissue?--An Experimental Ex Vivo Study

The protection of sensitive structures (e.g., nerves) from iatrogenic damage is of major importance when performing laser surgical procedures. Especially in the head and neck area both function and esthetics can be affected to a great extent. Despite its many benefits, the surgical utilization of a laser is therefore still limited to superficial tissue ablation. A remote feedback system which guides the laser in a tissue-specific way would provide a remedy. In this context, it has been shown that nerval structures can be specifically recognized by their optical diffuse reflectance spectra both before and after laser ablation. However, for a translation of these findings to the actual laser ablation process, a nerve protection within the laser pulse is of utmost significance. Thus, it was the aim of the study to evaluate, if the process of Er:YAG laser surgery--which comes with spray water cooling, angulation of the probe (60°) and optical process emissions--interferes with optical tissue differentiation. For the first time, no stable conditions but the ongoing process of laser tissue ablation was examined. Therefore, six different tissue types (nerve, skin, muscle, fat, cortical and cancellous bone) were acquired from 15 pig heads. Measurements were performed during Er:YAG laser ablation. Diffuse reflectance spectra (4500, wavelength range: 350-650 nm) where acquired. Principal component analysis (PCA) and quadratic discriminant analysis (QDA) were calculated for classification purposes. The clinical highly relevant differentiation between nerve and bone was performed correctly with an AUC of 95.3% (cortial bone) respectively 92.4% (cancellous bone). The identification of nerve tissue against the biological very similar fat tissue yielded good results with an AUC value of 83.4% (sensitivity: 72.3%, specificity: of 82.3%). This clearly demonstrates that nerve identification by diffuse reflectance spectroscopy works reliably in the ongoing process of laser ablation in spite of the laser beam, spray water cooling and the tissue alterations entailed by tissue laser ablation. This is an essential step towards a clinical utilization.

Prevalence and Associated Factors of Neurovascular Contact in Patients With Hemifacial Spasm

PURPOSE

This study aimed to observe the prevalence and associated factors of neurovascular contact hemifacial spasm (HFS).

DESIGN

This was a cross-sectional analytical study.

METHODS

Medical records of patients with HFS in a neuro-ophthalmology clinic in Thailand between June 2008 and June 2012 were reviewed. A positive magnetic resonance imaging finding was defined as an adjacent variant vessel that directly compressed or placed pressure on the affected facial nerve. Prevalence and associated factors were analyzed.

RESULTS

A total of 60 participants were enrolled, composed of 12 male patients and 48 female patients with a median age of 54 years [interquartile range (IQR), 44.0-64.75] and a disease duration ranging from 4 months to 16 years (median, 2 years; IQR, 1.0-6.0). The prevalence of neurovascular contact HFS was 41.7%. Neurovascular contact HFS was more prevalent among women, with an overall ratio of 3.33. In age group analysis, the prevalence was higher among older patients. In univariate analysis, right-sided symptoms and diabetes mellitus were statistically significant in their association with neurovascular contact HFS (P = 0.040 and P = 0.029, respectively). Right-sided symptoms were significant in a multiple logistic regression analysis (P = 0.038), with an odds ratio of 3.30 [95% confidence interval (CI), 1.07-10.15]. Diabetes mellitus was not statistically significant (P = 0.051), with an odds ratio of 9.99 (95% CI 0.99-96.34).

CONCLUSIONS

The prevalence of neurovascular contact in patients with HFS was 41.7%. Right-sided symptoms were significantly associated with this condition.

[The management of facial nerve tumors involving the internal auditory canal]

OBJECTIVE

10 summarize tne clinical features of the facial nerve tumors involving the internal auditory canal and promote the management of facial nerve tumor.

METHOD

We retrospectively reviewed the clinical manifestations, the experiences of diagnosis and treatment of the facial nerve tumor involving the internal auditory canal. All these 5 cases were enrolled during January 2013 to Apr 2015.

RESULT

Among the 5 cases, 3 cases were facial neurilemmoma and the others were facial neurofibroma. The main symptoms of facial nerve tumors involving the internal auditory canal most commonly were facial paralysis companied with hearing loss. All the patients accepted the surgical treatment with various approaches, 3 cases of translabyrinthine approach, 1 case of middle fossa approach, and 1 case of combination of translabyrinthine and transotic approach. Total tumor resection were achieved in all 5 cases. Facial-hypoglossal nerve anastomosis was performed in one case, another case was undergone great auricular nerve graft.

CONCLUSION

Surgical intervention for patients with facial neuroma involving internal auditory canal should be considered when facial weakness has deteriorated to grade 4. The management should be based on the patient's hearing, facial nerve function, tumor size and invasive extension to select the appropriate surgical procedures.

Facial nerve disorders: anatomical, histological and clinical aspects

Three main problems of facial nerve pathology and surgery are considered in this paper. The intraneural anatomy of the facial nerve with its consequences for surgery, especially surgery for facial hyperkinesia, is studied and an original method of selective funicular neurolysis is proposed as a symptomatic operation. Quantitative and qualitative findings in the normal facial nerve are compared to findings in nerves after palsy. The results show that the introduction of neurometric methods for the quantitative assessment may yield further parameters in the judgement of past pathological processes within the nerve. Finally, prognosis of peripheral facial palsy, seen through electrophysiological testing methods, is discussed.

Otitis complicated by Jacod's syndrome with unusal facial nerve involvement: Case report and review of literature

Otitis media is a well-known condition and its infra-temporal and intracranial complications are extremely rare because of the widespread usage of antibiotic treatment. We report a case of 63-year-old female with complaints of right-sided facial pain and diplopia. She had a history of acute otitis media before 4 months of admission to our neurology unit. Neurological examination showed that total ophthalmoplegia with ptosis, mydriasis, decreased vision and loss of pupil reflex on the right side. In addition, there was involvement of 5th and 7th cranial nerves. Neurological and radiological follow-up examinations demonstrated Jacod's Syndrome with unusual facial nerve damage and infection in aetiology. Sinusitis is the most common aetiology, but there are a few cases reported Jacod's Syndrome originating from otitis media.