Eighth Nerve Research Articles

Characterizing Hearing Outcomes Following Treatment of Cerebellopontine Angle Meningiomas

Abstract Objectives To characterize treatment and hearing outcomes for cerebellopontine angle (CPA) meningiomas with inherent risks of hearing loss and identify predictors of hearing loss for surgically treated lesions. Design Retrospective chart review. Setting Tertiary care medical center. Participants Adult patients with CPA meningiomas impinging upon cranial nerve VIII and/or pretreatment hearing loss managed with microsurgery or stereotactic radiosurgery (SRS) with Gamma Knife at our center between 2012 and 2023. Main Outcome Measures Hearing preservation rate was determined from analysis of patients with pretreatment serviceable hearing for whom hearing-preserving treatment was attempted. Surgical patients were further analyzed using multivariable Cox proportional hazards regression models to identify factors predictive of postoperative hearing loss. Results We identified 80 patients with CPA meningiomas meeting inclusion criteria who were managed with either microsurgery (43, 54%) or radiosurgery (37, 46%). Following SRS, hearing was preserved in 88% of cases. Following microsurgery, hearing was preserved in 71% of patients—all patients who lost hearing had tumors involving the internal auditory canal (IAC). Among surgical patients only, multivariable analysis accounting for preoperative hearing, recurrence status, lesion size, and patient age, the preoperative imaging finding that the CPA meningioma surrounded the vestibulocochlear nerve was significantly associated with hearing loss (hazard ratio: 10.3, 95% confidence interval: 1.3–81.4, p = 0.02). Conclusion Most patients with meningiomas of the CPA can experience preservation of hearing, even when there is risk of hearing loss based on pretreatment evaluation. IAC invasion and surrounding of eighth nerve by tumor may portend poorer hearing outcomes in surgically managed patients.

Demyelination and Na+ Channel Redistribution Underlie Auditory and Vestibular Dysfunction in PMP22-Null Mice.

Altered expression of peripheral myelin protein 22 (PMP22) results in demyelinating peripheral neuropathy. PMP22 exhibits a highly restricted tissue distribution with marked expression in the myelinating Schwann cells of peripheral nerves. Auditory and vestibular Schwann cells and the afferent neurons also express PMP22, suggesting a unique role in hearing and balancing. Indeed, neuropathic patients diagnosed with PMP22-linked hereditary neuropathies often present with auditory and balance deficits, an understudied clinical complication. To investigate the mechanism by which abnormal expression of PMP22 may cause auditory and vestibular deficits, we studied gene-targeted PMP22-null mice. PMP22-null mice exhibit an unsteady gait, have difficulty maintaining balance, and live for only ∼3-5 weeks relative to unaffected littermates. Histological analysis of the inner ear revealed reduced auditory and vestibular afferent nerve myelination and profound Na+ channel redistribution without PMP22. Yet, Na+ current density was unaltered, in stark contrast to increased K+ current density. Atypical postsynaptic densities and a range of neuronal abnormalities in the organ of Corti were also identified. Analyses of auditory brainstem responses (ABRs) and vestibular sensory-evoked potential (VsEP) revealed that PMP22-null mice had auditory and vestibular hypofunction. These results demonstrate that PMP22 is required for hearing and balance, and the protein is indispensable for the formation and maintenance of myelin in the peripheral arm of the eighth nerve. Our findings indicate that myelin abnormalities and altered signal propagation in the peripheral arm of the auditory nerve are likely causes of auditory deficits in patients with PMP22-linked neuropathies.

Preemptive strategies and lessons learned from complications encountered with microvascular decompression for hemifacial spasm.

Microvascular decompression (MVD) is the only curative treatment modality for hemifacial spasm (HFS). Although generally considered to be safe, this surgical procedure is surrounded by many risks and possible complications. The authors present the spectrum of complications that they met in their case series, the possible causes, and the strategies recommended to minimize them. The authors reviewed a prospectively maintained database for MVDs performed from 2005 until 2021 and extracted relevant data including patient demographics, offending vessel(s), operative technique, outcome, and different complications. Descriptive statistics with uni- and multivariable analyses for the factors that may influence the seventh, eighth, and lower cranial nerves were performed. Data from 420 patients were obtained. Three hundred seventeen of 344 patients (92.2%) with a minimum follow-up of 12 months had a favorable outcome. The mean follow-up (standard deviation) was 51.3 ± 38.7 months. Immediate complications reached 18.8% (79/420). Complications persisted in only 7.14% of patients (30/420) including persistent hearing deficits (5.95%) and residual facial palsy (0.95%). Temporary complications included CSF leakage (3.10%), lower cranial nerve deficits (3.57%), meningitis (0.71%), and brainstem ischemia (0.24%). One patient died because of herpes encephalitis. Statistical analyses showed that the immediate postoperative disappearance of spasms and male gender are correlated with postoperative facial palsy, whereas combined vessel compressions involving the vertebral artery (VA) and anterior inferior cerebellar artery can predict postoperative hearing deterioration. VA compressions could predict postoperative lower cranial nerve deficits. MVD is safe and effective for treating HFS with a low rate of permanent morbidity. Proper patient positioning, sharp arachnoid dissection, and endoscopic visualization under facial and auditory neurophysiological monitoring are the key points to minimize the rate of complications in MVD for HFS.

Analysis of Nonvestibular Cranial Nerve Schwannomas

Background and Aim: Cranial nerve (CN) schwannomas other than the eighth nerve schwannoma are called nonvestibular cranial nerve schwannomas (NVCNS). This study aims to analyze the clinical profile, distribution, and surgical outcome of the NVCNS. Methods and Materials/Patients: This is a retrospective study analyzing the NVCNS conducted between January 2007 and December 2021. VIIIth cranial nerve schwannomas and conservatively managed NVCNS were excluded from the study. Results: This study included 25 patients with NVCNS. Ten patients (40%) had trigeminal schwannomas, 3(12%) facial nerve schwannomas, 9 (36%) lower cranial nerve (LCN) schwannomas, 1 (4%) vagal schwannoma in neck and 2(8%) hypoglossal schwannomas. Eight patients (32%) were male and 17(68%) were female. The age of the patients ranges from 13 to 62 years (mean 39 years +/- 14 SD). Findings of cerebellar involvement, VIIIth CN involvement, and headache are the most common clinical features. The posterior cranial fossa is the most common location of the tumors. Thirteen patients (52%) underwent gross total resection (GTR), 7(28%) underwent neartotal resection (NTR) and 5(20%) underwent subtotal resection (STR). All the patients improved in the postoperative period. Facial nerve palsy is the most common cranial nerve palsy occurring in the postoperative period. Conclusion: Trigeminal and lower cranial nerve (LCN) schwannomas are the most common NVCNS. The retrosigmoid suboccipital approach is the most commonly used surgical approach for tumors located in the posterior cranial fossa. Since NVCNS are benign lesions, postoperative clinical improvement along with decreased complications should be the goal of the surgery. Hence, gross total resection is the most commonly achieved extent of resection, near-total or subtotal resection can be done wherever gross total resection (GTR) is not possible in NVCNS.

Inhibition of YAP/TAZ-driven TEAD activity prevents growth of NF2-null schwannoma and meningioma.

Schwannoma tumours typically arise on the eighth cranial nerve and are mostly caused by loss of the tumour suppressor Merlin (NF2). There are no approved chemotherapies for these tumours and the surgical removal of the tumour carries a high risk of damage to the eighth or other close cranial nerve tissue. New treatments for schwannoma and other NF2-null tumours such as meningioma are urgently required. Using a combination of human primary tumour cells and mouse models of schwannoma, we have examined the role of the Hippo signalling pathway in driving tumour cell growth. Using both genetic ablation of the Hippo effectors YAP and TAZ as well as novel TEAD palmitoylation inhibitors, we show that Hippo signalling may be successfully targeted in vitro and in vivo to both block and, remarkably, regress schwannoma tumour growth. In particular, successful use of TEAD palmitoylation inhibitors in a preclinical mouse model of schwannoma points to their potential future clinical use. We also identify the cancer stem cell marker aldehyde dehydrogenase 1A1 (ALDH1A1) as a Hippo signalling target, driven by the TAZ protein in human and mouse NF2-null schwannoma cells, as well as in NF2-null meningioma cells, and examine the potential future role of this new target in halting schwannoma and meningioma tumour growth.

IgG kappa multiple myeloma with isolated central nervous system relapse.

A 76-year-old male presented with acute renal failure and cast nephropathy was diagnosed with IgG kappa multiple myeloma (MM). His paraprotein was 40 g/L, kappa-free light chain level was 17,058 mg/L, kappa: lambda light chain ratio was 1445. An automated full blood count showed hemoglobin 90 g/L, white blood cells 2.96 × 109/L, neutrophil 1.7 × 109/L, and platelet 179 × 109/L. Bone marrow trephine sample was hypercellular with nearly 100% plasma cells, which were positive for CD138, CD56, and cyclin D1, and showed kappa light chain restriction. Fluorescence in situ hybridization analysis with dual color/dual probes for immunoglobulin heavy chain (IGH) and MYC genes (Cytocell) and whole genome screening using 8 × 60K oligonucleotide arrays (Agilent) performed on the CD138 enriched cells (CD138 microbeads Miltenyi Biotech) from the liquid bone marrow sample showed no evidence of IGH rearrangement, MYC rearrangement, 1q gain, 1p loss, 17p loss, or any clinically significant imbalance. He was treated with eight cycles of bortezomib, cyclophosphamide, and dexamethasone (VCD) to very good partial response. He relapsed 30 months after diagnosis with paraprotein of 36 g/L, kappa light chains of 10,000 mg/L, and creatinine of 498 μmol/L. He was treated with eight cycles of bortezomib, thalidomide, and dexamethasone (VTD) to paraprotein undetectable and kappa light chain 29 mg/L. Seven months post completion of VTD (4 years after myeloma diagnosis), he presented with abnormal gait, falls, and a left-sided facial droop. His paraprotein was 2 g/L and serum-free kappa light chain was 81 mg/L. Magnetic resonance imaging (MRI) head and whole spine showed multifocal diseases in spinal canal and intracranially, involving the cranial nerves most prominent the fifth, seventh, eighth, and hypoglossal nerve on the left, anterior surface of the inferior pons medulla (Figure 1A). There were multiple lesions in the cervical spine as well as in the thoracic spine (Figure 1B). Computerized tomography (CT) chest abdomen pelvis did not show the evidence of other new diseases. Plasma cells were detected in cerebral spinal fluid (CSF) (Figure 1C, May–Grünwald–Giemsa stain x100 objective). He was treated with pomalidomide and dexamethasone. Weekly cytarabine intrathecal (IT) treatment was given until the clearance of plasma cells from CSF samples for three times. Four months later, he achieved the complete remission on MRI head and whole spine with undetectable paraprotein and normal light chain ratio. Serial MRI scans confirmed ongoing remission. A year later, he relapsed again with worsening mobility and reappearance of myeloma cells in CSF. By flow cytometry, these cells were positive for CD138, CD38, CD56, CD117, and negative for CD19. MRI head showed leptomeningeal disease with a new 2.2 cm frontal lobe lesion. His paraprotein remained undetectable and kappa light chain remained at below 100 mg/L. He continued systemic pomalidomide and dexamethasone chemotherapy and received palliative whole brain radiotherapy 20 Gy in 5 fractions for symptom control. His disease continued progressing and he passed away 3 months later (5.5 years after myeloma diagnosis). Here, we reported a myeloma patient with isolated CNS relapse, who achieved 1 year of remission with combination of intrathecal chemotherapy and systemic pomalidomide and dexamethasone treatment, but sadly passed away 4 months after second CNS relapse. CNS MM is a rare form of extramedullary disease, but carries a very poor prognosis. The optimal approach to treatment of CNS MM is not currently known. The current approach includes systemic therapy with agents known to cross the blood brain barrier, intrathecal therapy, and CNS irradiation. Innovative approach to treatment is urgently needed. The authors received no specific funding for this work. Ke Xu and Lucy Kamuriwo wrote the manuscript. Ke Xu, Lucy Kamuriwo, Claire Anderson and Parag Jasani critically revised the final version of the manuscript. The authors declare they have no conflicts of interest. No written or verbal consent obtained from patient. Patient has passed away.

Vestibular paroxysmia: clinical characteristics and long-term course

In 2016, the Bárány Society defined new diagnostic criteria for the neurovascular compression syndrome of the eighth nerve, called “vestibular paroxysmia” (VP), differentiating between definite (dVP) and probable (pVP) forms. The aim of this study was (1) to describe clinical symptoms and laboratory findings in a well-diagnosed large patient cohort according to those criteria, and (2) to evaluate the long-term course over years in dVP. We identified 146 patients (73 dVP, 73 pVP) from our tertiary dizziness center registry. Data of structured history-taking, clinical neurological, neuro-ophthalmological/-otological examinations as well as MRI imaging were extracted for analyses. Overall, attack frequency ranged between 5 and 30 attacks per day; spinning vertigo was the most frequent type. In two-thirds of patients, attacks occurred spontaneously; in one-quarter, they were triggered by head movements. The majority (approximately 70%) reported no accompanying symptoms; in those with symptoms, mild unilateral cochlear symptoms prevailed. One-third of patients initially showed hyperventilation-induced nystagmus without specific direction, and a deviation of the subjective visual vertical between 3° and 6°. Complete loss of peripheral vestibular function was never evident. dVP and pVP significantly differed concerning the vertigo type, e.g., spinning vertigo was more frequent in dVP. Fortunately, three-quarters of dVP patients remained attack-free during follow-up (mean 4.8 years, standardized questionnaire), more than half of them even without any medication. Patients with ongoing attacks showed significantly higher attack frequency at baseline, but reported persistent frequency reduction. Overall, the long-term prognosis of VP appears favorable, not necessarily requiring ongoing treatment.

Bony Decompression of a Chronically Painful Intercostal Nerve Yields Immediate and Long-Lasting Pain Relief: A Case Report.

The case of an active 16-year-old adolescent girl who presented with rib malunion and 1 year of unremitting intercostal nerve pain after sustaining multiple rib fractures is presented. She underwent successful bony and soft-tissue decompression of her eighth and ninth intercostal nerves to relieve neurogenic symptoms. When conservative treatment fails, chronic intercostal nerve pain due to chest wall trauma may be effectively managed with surgical bony decompression of the offending intercostal bundle(s). Anatomic knowledge of the intercostal nerve and a critical history and physical examination were critical for accurate diagnosis and surgical decompression of the patient's intercostal nerve.

The Long and Winding Road-Vestibular Efferent Anatomy in Mice.

The precise functional role of the Efferent Vestibular System (EVS) is still unclear, but the auditory olivocochlear efferent system has served as a reasonable model on the effects of a cholinergic and peptidergic input on inner ear organs. However, it is important to appreciate the similarities and differences in the structure of the two efferent systems, especially within the same animal model. Here, we examine the anatomy of the mouse EVS, from its central origin in the Efferent Vestibular Nucleus (EVN) of the brainstem, to its peripheral terminations in the vestibular organs, and we compare these findings to known mouse olivocochlear anatomy. Using transgenic mouse lines and two different tracing strategies, we examine central and peripheral anatomical patterning, as well as the anatomical pathway of EVS axons as they leave the mouse brainstem. We separately tag the left and right efferent vestibular nuclei (EVN) using Cre-dependent, adeno-associated virus (AAV)-mediated expression of fluorescent reporters to map their central trajectory and their peripheral terminal fields. We couple this with Fluro-Gold retrograde labeling to quantify the proportion of ipsi- and contralaterally projecting cholinergic efferent neurons. As in some other mammals, the mouse EVN comprises one group of neurons located dorsal to the facial genu, close to the vestibular nuclei complex (VNC). There is an average of just 53 EVN neurons with rich dendritic arborizations towards the VNC. The majority of EVN neurons, 55%, project to the contralateral eighth nerve, crossing the midline rostral to the EVN, and 32% project to the ipsilateral eighth nerve. The vestibular organs, therefore, receive bilateral EVN innervation, but without the distinctive zonal innervation patterns suggested in gerbil. Similar to gerbil, however, our data also suggest that individual EVN neurons do not project bilaterally in mice. Taken together, these data provide a detailed map of EVN neurons from the brainstem to the periphery and strong anatomical support for a dominant contralateral efferent innervation in mammals.

Cranial nerve involvement in mucormycosis in post-COVID patients: a case series

BackgroundOne of the largest outbreaks of rhinosinocerebral mucormycosis (RSCM) occurred in India close to the second wave of the SARS-CoV-2 infection. RSCM is a rare infection caused by several fungal species occurring in immunocompromised subjects. Mucor shows a high propensity to invade the central nervous system. There have been limited studies, mostly isolated case reports, on the neurological manifestations of RSCM. The outbreak of mucormycosis infection was thus the most opportune to study the neurological manifestations and cranial nerve involvement in mucormycosis in greater depths.Aim of the studyThe purpose of the study was to investigate and review the involvement of cranial nerves in a series of cases of rhinosinocerebral mucormycosis associated with the novel coronavirus disease caused by SARS-CoV-2.ResultsIt was a retrospective cross-sectional study of seven patients who were undergoing treatment of RSCM with a recent history of coronavirus disease caused by SARS-CoV-2 infection within the last 3 months. Patients with cranial nerve involvement were identified by magnetic resonance imaging (MRI) at a single institution. Demographic details of the patients, clinical presentation, imaging, microbiological and pathological findings were recorded. All subjects had two or more cranial nerves affected by fungal infection. The most commonly involved cranial nerve was found to be the optic nerve followed by the trigeminal nerve and its branches. We document three cases with extensive involvement of the inferior alveolar branch of the mandibular division of the trigeminal nerve (V3), a previously unreported finding. In one case, in addition to the second and fifth cranial nerves, the third, fourth, sixth, seventh, eighth, and twelfth cranial nerves were involved without any sensory or motor long tract involvement, suggestive of Garcin syndrome secondary to intracranial abscesses and skull base osteomyelitis due to invasive fungal infection. This case is of rare occurrence in the literature, and our study provides one such example.ConclusionCranial nerve involvement in patients of mucormycosis tends to have a poor prognosis, both cosmetic and functional. Radical surgeries and aggressive medical management is needed in such cases to improve the outcome.

The reliability and quality of online patient education videos for vestibular schwannoma

Background A recent trend of looking for health-related conditions on the Internet has been described, with up 70% of searchers stating that online sources have affected their medical decision-making. Patients with vestibular schwannomas (VS) use online sources, including videos, to seek information about treatment alternatives and outcomes and surgeons experience. Our study investigates the reliability and quality of VS-related online videos. Methods In April 2020, a search was launched on YouTube for the key terms ‘vestibular schwannoma,’ ‘acoustic neuroma,’ ‘eighth cranial nerve schwannoma,’ and ‘eighth cranial nerve neuroma.’ Results were screened for possible inclusion. Three authors independently used the DISCERN instrument to evaluate the reliability and quality of the included videos. Factors possibly influencing popularity were investigated. Results The initial search yielded 6416 videos. 38 videos were included in the final analysis. The average DISCERN score was 2.76, indicating overall poor quality and reliability of information. Only 5% scored 4.0 or more (unbiased videos that offer evidence-supported information); 31% scored between 3.0 and 3.99, and 63% scored 2.99 or less. Videos describing symptoms or the patient’s clinical presentation were slightly more popular than videos without these characteristics. Surgical videos (videos containing clips of surgical procedures) were significantly more popular than non-surgical videos (p = .024) despite being of similarly poor quality (DISCERN score 2.85 vs. 2.74, respectively). Conclusions Available patient educational videos for VS are of mixed quality and reliability: the authors describe the strengths and pitfalls of existing YouTube videos. Considering that VS is a pathology with multiple available management modalities, and that patients’ decision-making is affected by the information available on the Internet, it is of great importance that good-quality informative material be released by medical, academic, or educational institutions.

Simultaneous Sudden Hearing Loss and Peripheral Facial Paralysis in a Patient With Covid-19.

Although peripheral facial paralysis and sudden sensorineural hearing loss are not as common as anosmia, they are reported neurological manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We present a 62-year-old, serologically COVID-19 positive woman with seventh and eighth nerve involvement showed electrophysiologically with Auditory Brainstem Response and electroneurography and radiologically with internal acoustic canal magnetic resonance imaging. This single case report suggests a possible association between the SARS-CoV-2 infection with simultaneous sudden sensorineural hearing loss and isolated facial paralysis. However, further studies are needed to determine whether this relationship is coincidental or occasional.

Nasal Schwannoma

Introduction A schwannoma is a benign nerve sheath tumuor of myelinated nerves arising from Schwann cells. In the head and neck region, the most common site is the eighth cranial nerve (vestibulocochlear). Only 4% of schwannomas seen in the head and neck region arise from the nose and paranasal sinuses involving branches of the trigeminal nerve (ophthalmic or maxillary) or from the autonomic nervous system. Case Report A 29 year old female patient presented to the Ear, Nose and Throat Out Patient Department with the complaints of left sided nasal obstruction and left sided nasal bleed. On anterior rhinoscopy, a single, smooth, greyish, non-pulsatile polypoidal mass was seen in the left nasal cavity seeming to be arising medial to middle turbinate. A provisional diagnosis of benign nasal mass was made and the patient underwent excision under general anaesthesia. On histopathology, an impression of Schwannoma was made. Discussion Sino-nasal schwannomas are a very rare entity with non specific imaging studies. A confirmatory diagnosis can be made only after histopathology. The treatment modality of choice is surgical excision of the mass, taking care to leave no residual, so as to prevent a recurrence.

Endoscopic-Assisted Microsurgery for Vestibular Schwannomas: Operative Nuances.

Vestibular schwannoma surgery is a challenging operative procedure. Intricate anatomy of vital neurovascular structures demands a meticulous planning and execution. The cerebellopontine angle is an unforgiving area of skull bases surgery which can have grave implications on patient outcome even after a successful tumor removal. As more and more tumors are being detected at early stage, functional preservation of seventh and eighth nerve complex is increasingly being demanded. The key to any minimally invasive approach is to minimize the collateral damage while ensuring complete tumor removal. Binocular microscopy is the workhorse for illumination and dissection via retrosigmoid approach. However, as instrumentation has improved, endoscopic dissections are increasingly being performed. The following video presents the step-by-step nuances for an endoscope-assisted microsurgery for small vestibular schwannomas with stress on endoscopic drilling of the meatal wall to deliver out intracanacular tumor while preserving the labrynthine structures.

Hypertrophic Pachymeningitis of the Internal Auditory Canal Induced by a Labyrinthine Fistula Complicated With Cholesteatoma

Hypertrophic pachymeningitis (HP) is defined by inflammation and thickening of the dura mater, and the etiologic factors are idiopathic or secondary to various conditions. To date, HP in the internal auditory canal (IAC) has rarely been reported. There have only been 3 reports of HP in the IAC. Magnetic resonance imaging showed enhancement of along the IAC and vestibule. After antibiotic treatment, enhancement was reduced with visible seventh and eighth nerves. The patient underwent tympanomastoidectomy. To our knowledge, this is the first case of HP associated with a labyrinth fistula complicated by cholesteatoma. We report MRI image with literatures.

Diagnostic Value of Dynamic High-frequency Ultrasound for the Slipping Rib and Twelfth Rib Syndrome: A Case Series with Review.

High-frequency ultrasound (HFUS) is a mobile, radiation-free imaging tool for the diagnosis of musculoskeletal disorders. We aim to demonstrate the diagnostic value of dynamic HFUS for undiagnosed lower chest, upper abdomen, and loin pain with this case series. A cricketer presented with long-standing left-sided dull ache lower chest and upper abdominal pain, aggravated on exertion and leaning forward. His previous laboratory and previous imaging tests were unrevealing. Dynamic HFUS of his left ribs during hooking maneuver demonstrated slipping of the eighth rib over the seventh rib associated with clicking. He also reported tenderness over this region. He was diagnosed with slipping rib syndrome (SRS), and was treated with the eighth nerve block under the HFUS guidance. The second and third cases presented with chronic undiagnosed waxing and waning loin pain despite extensive laboratory and radiological workup. Both patients demonstrated twelfth rib HFUS probe tenderness in a sitting position with a specific movement that reproduced the pain during the dynamic HFUS study. The diagnosis of twelfth rib syndrome (TRS) was confirmed and treated successfully with a local intercostal nerve block. HFUS is the most underutilized imaging tool for the diagnosis of unexplained upper abdominal and lower chest pain syndromes. We identified only a few such reported cases managed with the help of HFUS. The dynamic HFUS is a valuable imaging modality for the undiagnosed lower chest, upper abdominal, or loin pain.

Clinical outcomes of resecting scarpa's ganglion during vestibular schwannoma surgery

Vestibular schwannomas are slow-growing tumors arising from the Schwann cells of the vestibular nerve. Scarpa’s ganglion, the vestibular nerve ganglion, is located within the internal auditory meatus. Surgical treatment of vestibular schwannomas carries the potential of resecting Scarpa’s ganglion along with the tumor. No prior studies have evaluated outcomes based on the presence of Scarpa’s ganglion within tumor specimens. The neurosurgery patient records were queried for patients who underwent surgical resection of vestibular schwannomas at the University of Missouri Healthcare between January 1, 2008 and December 31, 2018. Inclusion criteria consisted of minimum age of 18, imaging demonstrating an eighth nerve tumor, surgical resection thereof, and a final pathological diagnosis of WHO grade I schwannoma. Data were collected retrospectively. The histological slides of the tumors were reviewed, and the presence or absence of the ganglion was noted. Outcomes analyzed included postoperative dizziness, hearing, and facial nerve function. Fifty-two patients met inclusion criteria. Ten (19%) resected tumors contained portions of the ganglion. No difference in risk of resection of ganglion occurred based on the surgical approach (p = 0.2454). Mean follow-up duration was 24.6 months ± 26.2 standard deviation. No differences in postoperative hearing or dizziness (p = 0.8483 and p = 0.3190 respectively) were present if Scarpa’s ganglion was resected. House-Brackmann classification of facial nerve function at last follow-up was similar (p = 0.9190). Resection of Scarpa’s ganglion with vestibular schwannomas does not increase risk of post-operative dizziness, facial nerve weakness, or hearing loss.

SURGERY OF JUGULAR FORAMEN LESIONS - AN INSTITUTIONAL EXPERIENCE

Jugular foramen tumors are rare skull base tumors having complex neurovascular anatomy. Most common being paragangliomas, lower cranial nerve schwannomas and meningiomas. Being the conduit for important neuro-vascular structures, potential complications following surgery are a frequent source of morbidity. Retrospective study done from March 2008 to September 2014. All patients underwent highresolution computer tomography (HRCT) of temporal bones and magnetic resonance imaging (MRI) with angiography in pre-operative period. Surgical approach and pre-operative endovascular intervention depended on the site and extent of the lesion. Extent of tumor removal was determined at the time of surgery. Patients with incomplete excisions in postoperative imaging were subjected to radiotherapy depending on histo-pathological diagnosis. Total of 22 patients of jugular foramen lesion were operated. Histopathological diagnosis included paraganglioma(n=18), schwannomas(n=2), p l a s m a c y t o m a ( n = 1 ) , s q u a m o u s c e l l carcinoma(n=1). Eighth cranial nerve was the most common involved nerve preoperatively (100%). Infratemporal Fossa approach, along with its modication, and conservative jugulopetrosectomy approach were used for surgical excision as per the extent of tumor. Complete excision was done in 73% (n=16), and postoperative radiotherapy was given to rest of the patients. The most common postoperative complication was lower cranial nerve decit in immediate post op period(n=15, 68%) (new onset n= 3, 13% and n=12, 55% had preoperative paresis), on follow up lower cranial nerve palsy improved in 50% in follow up (n=7). Most common tumor of the jugular foramen was paraganglioma followed by lower cranial nerve schwannoma. Surgical management depends on the extent of tumor. Multidisciplinary approach provides better patient outcome. Histopathological diagnosis aids to give targeted radiotherapy to the local site, and hence surgical excision of JFT(Jugular foramen tumor) is recommended.

Vestibular Paroxysmia with Trigeminal Neuralgia: Simultaneous Occurrence of Two Compression Syndromes: A Rare Case Report

AbstractNeurovascular compression syndromes are compression of cranial nerves by blood vessels leading to troublesome symptoms. They mostly occur due to a single vessel loop compression. Here, we report two rare cases with simultaneous fifth and eighth nerve compression by anterior inferior cerebellar artery and superior cerebellar artery loops together.

Intramuscular pathway and fascicular characteristics of the segmental intercostal innervation to rectus abdominis.

Rectus abdominis is a muscle that is commonly used clinically as a muscle flap, especially in reconstructive surgery. Its intramuscular innervation, however, has rarely been examined in detail or accurately mapped. The purpose of this study was to use biopsied, histological specimens complemented with a staining technique to investigate intramuscular nerve connections and distribution of the rectus abdominis. Four fresh human cadavers were included in the study and rectus abdominis was dissected bilaterally. Nerve sections innervating the rectus abdominis were biopsied and histologically processed. Sections were viewed under the microscope, and axons within each fascicle were counted using imaging software. All specimens were stained with a modified Sihler's staining technique. Intramuscular innervation was observed and the number as well as distribution was recorded. Macroscopically stained specimens showed that the eighth, ninth, 10th and 12th intercostal nerves innervated the eight muscle bellies of rectus abdominis. The greatest number of minor nerve branching as well as intramuscular nerve communications originated from nerve roots T9 and T10. Minor nerve branches crossed tendinous intersections to communicate with adjacent nerves and innervate adjacent muscle bellies. Nerves originating from T9 had the greatest number of nerve fascicles and the highest axon count in each cadaver. The rectus abdominis is divided into four compartments with each receiving its own independent nerve supply. Minor nerve branches crossed tendinous intersections to communicate with adjacent muscle bellies and nerves suggesting that rectus abdominis can be used as a whole in innervated free flap transfer procedures.