Different types of dysphagia alleviated by the chin-down position.

OBJECTIVE: Retrospective videofluoroscopic swallowing study (VFSS) evaluations of pharyngeal swallowing were used to evaluate the types of dysphagia alleviated by the chin-down maneuver. MATERIALS AND METHODS: The study population consisted of 64 patients who underwent VFSS evaluations during neutral and chin-down maneuvers presenting specifically penetration or aspiration. The assessment of the VFSS movie clips of each maneuver was performed using parameters of the Modified Barium Swallow Impairment Profile (MBSImP) and the presence and degree of airway invasion(PDAI) by three blinded raters in the following five subcategorized groups, 1. patietns presenting penetration or aspiration during swallow 2. after swallow, patients of 3. head and neck, 4. digestive and 5. neuromuscular disorders, respectively. The scores registered for the two maneuvers were statistically compared. Additionally, we examined statistically which factors had the impact on the improvement of the PDAI using fisher's exact test. RESULTS: Compared with the neutral position, PDAI, pharyngeal constriction, anterior hyoid movement, pharyngeal constriction, laryngeal elevation, laryngeal closure, upper esophageal sphincter opening, initiation of the pharyngeal swallow, and pharyngeal clearance in pyriform sinus were significantly (p < 0.01-0.05) improved with the chin-down maneuver. In a subcategory comparison with group 1, 3 and 4, the PDAI improved significantly (p < 0.01) with the chin-down maneuver, in which laryngeal elevation and laryngeal closure had statistically the impact (p < 0.01-0.05) on improvement of PDAI. CONCLUSION: The chin-down maneuver was most effective in improving swallow function when the impairment included penetration and aspiration during swallow caused by inadequate laryngeal elevation and laryngeal closure.

Electrophysiological predictors of hearing deterioration based on AEP monitoring during petroclival meningioma resection.

The objective of this study was to calculate the risk of postsurgical hearing deterioration as a function of changes in the amplitude and latency of the most stable components (waves III and V) of the auditory evoked potential (AEP) during petroclival meningioma resection surgery. We retrospectively analyzed intraoperative AEP monitoring results and pre- and postsurgical hearing status in 40 consecutive patients who were surgically treated for petroclival meningiomas. Statistical analyses were conducted to identify the most sensitive and specific way to predict hearing dysfunction after surgery. Patients' mean age was 59 ± 10 years, and 31 (77.5%) were women. Twelve (30%) patients presented with clinically detectable hearing impairment preoperatively. At the first postoperative assessment, four of those 12 patients reported subjective improvement, and eight reported hearing deterioration. Of those eight, four remained stable and four recovered hearing by the last assessment. Wave III latency reached its highest specificity (100%) and sensitivity (71.43%) at x = 143%. Wave V latency, on the other hand, reached its highest sensitivity (71%) and specificity (93%) at x = 124%. Finally, wave V amplitude reached its highest sensitivity (100%) and specificity (79%) at x = 74%. Intraoperative alterations of wave III latency and wave V amplitude seem to be highly sensitive and specific at predicting the risk of auditory dysfunction in patients undergoing petroclival meningioma resection and should be used to determine maximum resection with preservation of function.

Application of the Scale for the Assessment and Rating of Ataxia (SARA) in pediatric oncology patients: A multicenter study.

Posterior cranial fossa (PCF) tumors in childhood are often associated with ataxia as well as other motor, neurobehavioral and linguistic impairment. The use of a reliable outcome measure is mandatory to evaluate the severity of impairment and monitor rehabilitation effectiveness. The aim of this work is to explore the validity of the Scale for the Assessment and Rating of Ataxia (SARA) in pediatric subjects with ataxia secondary to PCF tumor resection and evaluate the influence of age and comorbidities. Seventy eight patients (3-18 years) were recruited in 5 centers from 2016 to 2018. The age effect on SARA was analyzed by correlating total SARA scores and item scores with age and gradually excluding youngest subjects. The comorbidity effect was evaluated by comparing the ataxia-only group vs a group of subjects with ataxia + dysfunction of cranial nerves or cerebellar mutism (CM) and a group of patients with ataxia + hemiparesis. Several negative correlations between SARA scores and age were found under age 9. Differences between ataxia-only group and the other two groups were closely associated with specific comorbidities (e.g. speech disturbance in cranial nerves or CM group (p value < 0.001) and gait, stance, sitting and finger chase in the hemiparetic group (mean p value 0.022)).

Development of a Novel Orthotopic Primary Human Chordoma Xenograft Model: A Relevant Support for Future Research on Chordoma.

Chordomas are slow-growing rare malignant neoplasms. The aim of this study was to establish a primary model of chordoma in the lumbosacral orthotopic area, to compare the growth rate to the subcutaneous site, and to show that this new graft site optimizes tumor growth and bony invasion. Eleven chordoma samples were transplanted subcutaneously in the flank and/or in contact with the lumbosacral region and grown into nude mice. Engraftment rate was significantly more successful in the lumbosacral environment compared with the flank at P0. Two xenografts from 2 patients showed bone invasion. One tumor was maintained through multiple rounds of serial transplantation, creating a model for study. Histological and immunostaining analysis confirmed that tumor grafts recapitulated the primary tumor from which they were derived, consisting of a myxoid chordoma expressing brachyury, cytokeratin AE1, EMA, and VEGF. Clear destruction of the bone by the tumor cells could be demonstrated. Molecular studies revealed PIK3CA and PTEN mutations involved in PI3K signaling pathway and most of the frequently reported chromosomal alterations. We present a novel orthotopic primary xenograft model of chordoma implanted for the first time in the lumbosacral area showing bone invasion, PIK3CA, and PTEN mutations that will facilitate preclinical studies.

Endoscopic endonasal skull base surgery for pediatric brain tumors.

PURPOSE: The utility of endoscopic endonasal skull base surgery (EES) in various pathologic entities in adults has been published in the literature. However, the role of EES in children has not been clearly elucidated. We evaluated the feasibility of EES in children with brain tumors. METHODS: We retrospectively reviewed clinical features, surgical outcomes, and complications in children who underwent EES for intracranial and skull base tumors at a single institution from July 2010 to October 2018. RESULTS: A total of 82 patients underwent EESs for 77 intracranial and 5 skull base bony tumors. The mean age at diagnosis was 11.4 years (range 4-18 years), and the mean follow-up period was 46.8 months. The most common tumors were craniopharyngioma in the intracranial tumor and chordoma in the skull base. Gross total resection was the goal of surgery in 55 patients and achieved in 90.9%. The vision was improved in 76.1% of patients with visual impairments. Preoperatively, various endocrinological deficiencies were revealed in 73.7% of 76 patients with hypothalamus-pituitary lesions, and the hyposomatotropism was most common. Endocrinological status was improved only in 10. Aseptic or bacterial meningitis (7.3%) was the most common surgical complication, and the cerebrospinal fluid leakage rate was 2.4%. CONCLUSIONS: EES provides favorable neurological outcomes with acceptable risk for children with brain tumors. The high incidence of endocrinological deficits in cases with hypothalamus-pituitary lesions emphasizes the importance of judicious pre- and postoperative evaluation.

Endoscopic Endonasal Removal of Primary/Recurrent Meningiomas in the Medial Optic Canal: Surgical Technique and Long-Term Visual Outcome.

BACKGROUND: Tuberculum sellae meningiomas frequently extend into the optic canals, which leads to a progressive longitudinal visual loss. Therefore, in addition to tumor removal, unroofing and exploration inside the optic canal are important procedures. OBJECTIVE: To perform endoscopic endonasal tumor removal with optic canal decompression for small primary or recurrent meningiomas associated with a progressive visual loss at the inferior-medial optic canal, which corresponded to a blind corner in the ipsilateral pterional/subfrontal approach. METHODS: We retrospectively reviewed 2 cases of primary meningiomas that arose in the inferior-medial optic canal and 4 recurrent cases from the remnant inside the medial optic canal that had previously undergone craniotomy for tuberculum sellae meningiomas, and were treated by the endoscopic endonasal approach. RESULTS: All tumors were detectable and could be removed without manipulation of the affected optic nerve. The average maximum diameter of the tumor was 8.4 mm (range: 5-12 mm). Two patients who had a long history of progressive visual disturbance and papillary atrophy did not recover from severe visual disturbances postoperatively. However, others showed considerable improvement, maintaining postoperative visual function during follow-up. There were no postoperative complications. CONCLUSION: Endoscopic endonasal approach has several advantages for meningiomas in the medial optic canal and associated with progressive visual disturbance. In surgery of tuberculum sellae meningiomas, optic canal decompression and exploration inside the optic canal are important procedures to avoid symptomatic recurrence, which may be facilitated by the endoscopic endonasal approach. Papillary atrophy and duration of visual deterioration are predictive factors for postoperative visual outcomes.

Sinonasal quality of life after endoscopic resection of malignant sinonasal and skull base tumors.

OBJECTIVES: Improvement in sinonasal quality of life (QoL) following sinus surgery has been well-documented across the literature. To our knowledge, only one series has evaluated long-term QoL in patients undergoing tumor resection, and that study demonstrated no improvement in rhinologic QoL following malignant tumor resection at 2-year follow-up. The objective of the present study was to evaluate QoL in the 2 years following endoscopic malignant tumor resection. METHODS: A prospective cohort study was performed, including patients with both malignant and benign sinonasal tumors in a tertiary academic medical center. Patients undergoing endoscopic tumor resection who had completed Sinonasal Outcome Test 22 (SNOT-22) questionnaires were included in the cohort. SNOT-22 questionnaires were administered preoperatively and over a 2-year follow-up period at clinic visits. Longitudinal linear mixed-effects regression was used to compare preoperative QoL to QoL over the 2 years following surgery. RESULTS: Among 145 patients included in this study, 64 had malignant tumors. There was a statistically significant improvement in SNOT-22 score from baseline to 2 years for patients with both malignant tumors (37.0, 95% confidence Interval [CI] 32.0-42.1 at baseline; 26.5 95% CI 20.8-32.2 at 2 years; P < 0.001) and benign tumors (26.5, 95% CI 21.4-30.4 at baseline; 12.9 95% CI 7.6-18.2 at 2 years; P < 0.001). CONCLUSION: In contrast to previously reported series, in this cohort endoscopic resection of sinonasal tumors appears to be followed by an improvement in QoL, which is sustained over a 2-year period. LEVEL OF EVIDENCE: 2b. Laryngoscope, 128:789-793, 2018.

[A supraorbital trans-eyebrow approach in surgery of chiasmatic-sellar and anterior cranial fossa tumors]. / Supraorbital'nyi transbrovnyi dostup v khirurgii opukholei khiazmal'no-selliarnoi oblasti i perednei cherepnoi iamki.

OBJECTIVE: to analyze 31 resections of chiasmatic-sellar region (CSR) and anterior cranial fossa (ACF) tumors using the supraorbital trans-eyebrow approach (STA). MATERIAL AND METHODS: We analyzed medical histories of 31 patients who underwent tumor resection using STA in the period between October 2013 and April 2017. We analyzed the age and gender of patients, size and location of the tumor, presence of a neurological deficit, vision and olfactory functions before and after surgery, surgery duration, amount of intraoperative blood loss, rate of frontal sinus trephination and nasal liquorrhea, hemorrhagic and ischemic complications after surgery, Simpson grade of tumor resection, patient's condition before and after surgery (Glasgow Outcome Scale and Karnofsky Scale), and degree of patient satisfaction with the cosmetic result of surgery. A total of 26 meningiomas (20 sphenoid plate, tubercle, and diaphragm tumors, 3 lesser sphenoid wing meningiomas, 2 orbital roof tumors, and 1 anterior clinoid process meningioma), 3 frontal lobe gliomas, and 2 pituitary adenomas were resected. RESULTS: In all 31 operations, the approach was adequate and enabled tumor resection without lethal outcomes. The mean surgery duration was 174.6±64.4 min. The mean blood loss was 190±96.6 mL (50-380 mL). After surgery, none of the patients developed motor deficits and new epileptic seizures. Neurological deficit aggravation in the form of impaired vision and mental disorders occurred in 8 (25.8%) patients. Vision impaired in 4 (12.9%) patients, improved in 6 (19.3%) patients, and remained unchanged in 21 (67.7%) patients. An endocrinological deficit in the form of partial hypopituitarism developed in 3 (9.6%) patients; in 4 (12.9%) patients, there were mental disorders that regressed by the end of the first month of therapy. There were no intracerebral and subarachnoid hemorrhages. In 2 (6.4%) patients, small epidural hematomas were diagnosed, which did not require surgical treatment. There were only good outcomes (a GOS score of 4 or 5). After surgery, the median Karnofsky index in the STA group was 90±7. In all 31 (100%) patients, the postoperative wound healed by primary intention, without infectious complications and wound liquorrhea. One (4%) patient developed eyebrow palsy; 3 (12%) patients had hypoesthesia in the supraorbital region. The mean VAS score of patient satisfaction with the cosmetic result was 9.36 (median 10±1). The mean follow-up period was 16.2±13.5 months (2-38 months). CONCLUSION: The STA is adequate for removal of CSR and ACF tumors under proper selection of patients. It provides an adequate view of anatomical structures and enables successful tumor resection through a less traumatic access.

Isolated clival metastasis: a rare presentation of renal cell carcinoma.

Renal cell carcinoma accounts for 3% of all adult malignancies. Usual sites of metastasis are lymph nodes, lungs, bone, liver and brain. We describe a patient who presented with complaints of holocranial headache and diplopia. MRI of the head showed a clival-based lesion with associated bony erosion. With suspicion of a metastatic lesion, an ultrasonogram of the abdomen was done which showed a left renal mass that enhanced on contrast-enhanced CT. There were no other metastatic foci. Patient underwent radiotherapy for the clival lesion. This case report emphasises on the evaluation of clival lesion with cranial neuropathies for a possibility of a renal primary tumour.

Definitive surgical treatment of osteomalacia induced by skull base tumor and determination of the half-life of serum fibroblast growth factor 23.

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome often associated with fibroblast growth factor 23 (FGF23)-producing tumors such as phosphaturic mesenchymal tumor, mixed connective tissue variant (PMTMCT) affecting the bone and soft tissue. We experienced a patient with progressive bone and muscle pain due to FGF23-related TIO. Venous sampling had strongly suggested the anterior skull base as a source of FGF23, which led to the discovery of a small tumor in the ethmoid sinus extending intracranially. Radical surgical resection confirmed the histological diagnosis of PMTMCT with FGF23 immunopositivity and achieved durable tumor control with complete resolution of symptoms. We serially measured serum FGF23 level before, during and after surgery and analyzed the data to determine the half-life of FGF23. Serum FGF23 level sharply declined as early as 20 minutes after en bloc tumor resection and completely normalized after surgery. The half-life of FGF23 was calculated to be approximately 18.5 minutes using single phase exponential decay model as well as semilog transformation formula. Serial measurements of serum FGF23 level can potentially declare "complete" resection of a FGF23-producing tumor and total cure of TIO; in this regard, development of its intraoperative measurement would be helpful in the management of this endocrine tumor.

[The transperygoid approach to the removal of a recurrent juvenile angiofibroma at the base of the skull without preoperative embolization]. / Transkrylovidnoe udalenie retsidiviruiushchei iuvenil'noi angiofibromy osnovaniia cherepa bez predoperatsionnoi émbolizatsii.

The authors report a clinical case of successful elimination of a recurrent juvenile angiofibroma at the base of the skull (JAFBS) with the application of the optical navigation system and a cold plasma scalpel in the absence of preoperative embolization. It has been demonstrated using the proposed transperygoid approach to the extirpation of the tumour that a recurrent juvenile angiofibroma at the base of the skull can be efficiently removed by means of a modern minimally invasive and at the same time radical surgical method.

Diffuse midline skull base meningiomas: identification of a rare and aggressive subgroup of meningiomas.

Skull base meningiomas may present as clinically aggressive tumors despite being histologically benign. Here we describe a clinico-radiological entity of diffuse midline skull base meningiomas responsible for several neurological morbidities, including hearing and vision loss, intracranial hypertension, secondary hydrocephalus and tonsillar herniation with spinal cord compression. Surgery and radiotherapy were ineffective in stopping the clinical course of those tumors. After targeted sequencing of known mutated genes in meningiomas, we discovered TRAF7 mutations in two out of four tumors, stressing the importance of focusing the research efforts of the meningioma community in understanding the mechanisms underlying TRAF7 related meningioma tumorigenesis.

Pediatric Skull Base Meningiomas: Clinical Features and Surgical Outcomes.

The purpose of this study is to investigate the clinical, pathological, and prognostic characteristics of pediatric skull base meningiomas. A retrospective analysis of 44 pediatric skull base patients younger than 18 years who underwent surgery at Beijing Tiantan Hospital was performed. The study group included 20 males and 24 females. Multiple lesions were seen in 8 patients. WHO grade I was found in 28 patients and higher grade was seen in 16 patients. Recurrence or progression occurred in 10 patients after the initial operation. The overall survival rate in the follow-up period for the entire cohort was 89.7%. The authors found no sex predominance in pediatric skull base meningiomas. In addition, this lesion was more often seen in their second decades. In contrast to skull base meningiomas in adult patients, pediatric skull base meningiomas had a higher incidence of nonbenign histopathological variants and a higher rate of recurrence.

[Etiology and pathogenesis of glomus tumours (chemodectomas) of the base of the skull].

The objective of the present work was to describe the poorly known history of the development of the nomenclature of glomus tumours (chemodectomas) of the base of the skull, elucidate etiology and pathogenesis of these neoplasms. The authors present a chronological table illustrating the progress of etiological and pathogenetic studies as well as the surgical treatment of the tumours. The results of analysis and discussion of the controversial issues of the nomenclature are reported.

Intraoperative neurophysiological monitoring during endoscopic endonasal surgery for pediatric skull base tumors.

OBJECT The aim of this study was to evaluate the value of intraoperative neurophysiological monitoring (IONM) using electromyography (EMG), brainstem auditory evoked potentials (BAEPs), and somatosensory evoked potentials (SSEPs) to predict and/or prevent postoperative neurological deficits in pediatric patients undergoing endoscopic endonasal surgery (EES) for skull base tumors. METHODS All consecutive pediatric patients with skull base tumors who underwent EES with at least 1 modality of IONM (BAEP, SSEP, and/or EMG) at our institution between 1999 and 2013 were retrospectively reviewed. Staged procedures and repeat procedures were identified and analyzed separately. To evaluate the diagnostic accuracy of significant free-run EMG activity, the prevalence of cranial nerve (CN) deficits and the sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS A total of 129 patients underwent 159 procedures; 6 patients had a total of 9 CN deficits. The incidences of CN deficits based on the total number of nerves monitored in the groups with and without significant free-run EMG activity were 9% and 1.5%, respectively. The incidences of CN deficits in the groups with 1 staged and more than 1 staged EES were 1.5% and 29%, respectively. The sensitivity, specificity, and negative predictive values (with 95% confidence intervals) of significant EMG to detect CN deficits in repeat procedures were 0.55 (0.22-0.84), 0.86 (0.79-0.9), and 0.97 (0.92-0.99), respectively. Two patients had significant changes in their BAEPs that were reversible with an increase in mean arterial pressure. CONCLUSIONS IONM can be applied effectively and reliably during EES in children. EMG monitoring is specific for detecting CN deficits and can be an effective guide for dissecting these procedures. Triggered EMG should be elicited intraoperatively to check the integrity of the CNs during and after tumor resection. Given the anatomical complexity of pediatric EES and the unique challenges encountered, multimodal IONM can be a valuable adjunct to these procedures.

Hypofractionated stereotactic radiation therapy in skull base meningiomas.

To investigate the role of hypo-fractionated stereotactic radiation treatment (HSRT) in the management of skull base meningioma. Twenty-six patients were included in the study and treated with a dose of 30 Gy in 5 fractions with volumetric modulated arc therapy (RapidArc). Eighteen patients were symptomatic before treatment. Endpoints were local toxicity and relief from symptoms. Tumors were located in anterior skull base in 4/27 cases, in middle skull base in 12/27 and in posterior skull base in 11/27. HSRT was performed as first treatment in 17 (65 %) patients, in 9 (35 %) patients it followed a previous partial resection. Median follow up was 24.5 months (range 5-57 months). clinical remission of symptoms, complete or partial, was obtained in the vast majority of patients after treatment. Out of the 18 symptomatic patients, partial remission occurred in 9 (50 %) patients and complete remission in 9 (50 %). All asymptomatic patients retained their status after treatment. No severe neurologic toxicity grade III-IV was recorded. No increase of meningioma in the same site of treatment occurred; 16 (62 %) patients had stable disease and 9 (38 %) patients had tumor reduction. The mean tumor volume after treatment was 10.8 ± 17.8 cm(3) compared with 13.0 ± 19.1 cm(3) before treatment (p = 0.02). The mean actuarial OS was 54.4 ± 2.8 months. The 1- and 2-years OS was 92.9 ± 0.7 %. HSRT proved to be feasible for these patients not eligible to full surgery or to ablative radiation therapy. Local control and durability of results suggest for a routine application of this approach in properly selected cases.

Surgical treatment of jugular foramen schwannomas.

OBJECTIVE: We present our experience with surgery of jugular foramen schwannomas with special consideration of clinical presentation, surgical technique, complications, and outcomes. METHODS: This retrospective study includes ten patients with jugular foramen schwannomas treated by the senior author between January 2007 and December 2012. Three patients had undergone partial tumour resection elsewhere. The initial symptom for which they sought medical help was hearing loss, dysphagia, hoarseness, and shoulder weakness. Preoperative glossopharyngeal and vagal nerve deficits were the most common signs. In our series, tumour extension was classified according to Kaye-Pellet grading system. In two cases the tumours were classified into type A and 8 patients presented with type D tumours. A retromastoid suboccipital craniotomy was performed for type A tumours and modifications of cranio-cervical approach were suitable for type D. RESULTS: No death occurred in this series. Four patients deteriorated after surgery: in two patients preoperative cranial nerve deficits deteriorated after surgery while new cranial nerve palsy occurred in 2 other patients. In four patients, the cranial nerve dysfunction had improved at the last follow-up examination. In all other patients, the cranial nerve dysfunction remained the same. One patient experienced tumour recurrence over a follow-up period of 40 months. This patient underwent a successful second surgery without further evidence of tumour growth. CONCLUSIONS: Jugular foramen schwannomas can be radically managed with the use of skull base surgery techniques. However, the surgical treatment of jugular foramen schwannomas carries a significant risk of the lower CN deficits.

Assessment of tumor blood flow and its correlation with histopathologic features in skull base meningiomas and schwannomas by using pseudo-continuous arterial spin labeling images.

OBJECTIVE: We aimed to investigate whether pseudo-continuous arterial spin labeling (pcASL)-MRI can adequately evaluate tumor perfusion even if the tumors are located in the skull base region and evaluate the correlation between tumor blood flow (TBF) and the histopathologic features of skull base meningiomas and schwannomas. MATERIALS AND METHODS: We enrolled 31 patients with skull base meningioma (n=14) and schwannoma (n=17) who underwent surgical resection. TBF was calculated from pcASL. Tissue sections were stained with CD34 to evaluate microvessel area (MVA). TBF and MVA ratio were compared between meningiomas and schwannomas using Mann-Whitney U-test. The correlations between MVA ratio and TBF were evaluated in each tumor by using single linear regression analysis and Spearman's rank correlation coefficients (rs). RESULTS: MVA ratio and TBF were significantly higher in meningioma than in schwannoma (both p<0.01). Correlation analyses revealed significant positive correlations between MVA ratio and both mean and max TBF for meningiomas (rs=0.89, 0.81, both p<0.01). There was a weak positive correlation between MVA ratio and mean TBF for schwannomas (rs=0.43, p=0.04). However, no significant correlation was found between MVA ratio and max TBF for schwannoma. CONCLUSIONS: pcASL-MRI is useful for evaluating tumor perfusion even if the tumors are located in the skull base region. Moreover, pcASL-TBF was significantly higher in most meningiomas compared to schwannomas, which can help in the differential diagnosis of the 2 tumor types even without the use of contrast material.

Facial Motor Neuron Excitability in Hemifacial Spasm: A Facial MEP Study.

INTRODUCTION: Hemifacial spasm (HFS) may be due to peripheral axon ephapsis or central motor neuron hyperexcitability. Low facial motor evoked potential (MEP) thresholds or MEP responses to single pulse stimulation (normally multipulse stimulation is needed) may support the central hypothesis. METHODS: We retrospectively compared response thresholds for facial MEPs in 65 patients undergoing surgical microvascular decompression (MVD) for HFS and 29 patients undergoing surgery for skull base tumors. RESULTS: Single pulse stimulation elicited facial Mep in up to 87% of HFS patients whereas only 10% of tumor patients responded to single pulse stimulation. When comparing facial MEP thresholds using multi-pulse stimulus trains the voltage required in the HFS group were significantly lower then in skull base tumor patients (p < 0.001). the MEP latencies and amplitudes at threshold stimulation were similar between the two groups. CONCLUSIONS: these results suggest the facial corticobulbar pathway demonstrates enhanced excitability in HFS.