Stereotactic Radiotherapy for Intracranial Nonacoustic Schwannomas Including Facial Nerve Schwannoma

Task force of the Brazilian Society of Otology - evaluation and management of peripheral facial palsy

OBJECTIVE

To review key evidence-based recommendations for the diagnosis and treatment of peripheral facial palsy in children and adults.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on peripheral facial palsy were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 main parts: (1) Evaluation and diagnosis of facial palsy: electrophysiologic tests, idiopathic facial palsy, Ramsay Hunt syndrome, traumatic peripheral facial palsy, recurrent peripheral facial palsy, facial nerve tumors, and peripheral facial palsy in children; and (2) Rehabilitation procedures: surgical decompression of the facial nerve, facial nerve grafting, surgical treatment of long-term peripheral facial palsy, and non-surgical rehabilitation of the facial nerve.

CONCLUSIONS

Peripheral facial palsy is a condition of diverse etiology. Treatment should be individualized according to the cause of facial nerve dysfunction, but the literature presents better evidence-based recommendations for systemic corticosteroid therapy.

Quantitative Analysis of the Effect of Stereotactic Radiosurgery for Postoperative Residual Cervical Dumbbell Tumors: A Multicenter Retrospective Cohort Study

OBJECTIVE

Stereotactic radiosurgery (SRS) has been performed for spinal tumors. However, the quantitative effect of SRS on postoperative residual cervical dumbbell tumors remains unknown. This study aimed to quantitatively evaluate the efficacy of SRS for treating postoperative residual cervical dumbbell tumors.

METHODS

We retrospectively reviewed cases of postoperative residual cervical dumbbell tumors from 1995 to 2020 in 2 tertiary institutions. Residual tumors underwent SRS (SRS group) or were observed with clinical and magnetic resonance imaging (MRI) follow-up (observation group). Tumor regrowth rates were compared between the SRS and observation groups. Additionally, risk factors for tumor regrowth were analyzed.

RESULTS

A total of 28 cervical dumbbell tumors were incompletely resected. Eight patients were in the SRS group, and 20 in the observation group. The mean regrowth rate was not significantly lower (p = 0.784) in the SRS group (0.18 ± 0.29 mm/mo) than in the observation group (0.33 ± 0.40 mm/mo). In the multivariable Cox regression analysis, SRS was not a significant variable (hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.18-1.79; p = 0.336).

CONCLUSION

SRS did not significantly decrease the tumor regrowth rate in our study. We believe that achieving maximal resection during the initial operation is more important than postoperative adjuvant SRS.

Management of non-vestibular schwannomas in adult patients: a systematic review and consensus statement on behalf of the EANS skull base section. Part I: oculomotor and other rare non-vestibular schwannomas (I, II, III, IV, VI)

BACKGROUND

Non-vestibular schwannomas are relatively rare, with trigeminal and jugular foramen schwannomas being the most common. This is a heterogeneous group which requires detailed investigation and careful consideration to management strategy. The optimal management for these tumours remains unclear, and there are several controversies. The aim of this paper is to provide insight into the main principles defining management and surgical strategy, in order to formulate a series of recommendations.

METHODS

A task force was created by the EANS skull base section along with its members and other renowned experts in the field to generate recommendations for the surgical management of these tumours on a European perspective. To achieve this, the task force performed an extensive systematic review in this field and had discussions within the group. This article is the first of a three-part series describing non-vestibular schwannomas (I, II, III, IV, VI).

RESULTS

A summary of literature evidence was proposed after discussion within the EANS skull base section. The constituted task force dealt with the practice patterns that exist with respect to pre-operative radiological investigations, ophthalmological assessments, optimal surgical and radiotherapy strategies and follow-up management.

CONCLUSION

This article represents the consensually derived opinion of the task force with respect to the treatment of non-vestibular schwannomas. For each of these tumours, the management of these patients is complex, and for those which are symptomatic tumours, the paradigm is shifting towards the compromise between function preservation and progression-free survival.

Outcomes after stereotactic radiosurgery for schwannomas of the oculomotor, trochlear, and abducens nerves

OBJECTIVE

Cranial nerve (CN) schwannomas are intracranial tumors that are commonly managed by stereotactic radiosurgery (SRS). There is a large body of literature supporting the use of SRS for vestibular schwannomas. Schwannomas of the oculomotor nerves (CNs III, IV, and VI) are rare skull base tumors, occurring close to the brainstem and often involving the cavernous sinus. Resection can cause significant morbidity, including loss of nerve function. As for other schwannomas, SRS can be used to manage these tumors, but only a handful of cases have been published so far, often among reports of other uncommon schwannoma locations.

METHODS

The goal of this study was to collect retrospective multicenter data on tumor control, clinical evolution, and morbidity after SRS. This study was performed through the International Radiosurgery Research Foundation. Patients managed with single-session SRS for an oculomotor cranial nerve schwannoma (CN III, IV, or VI) were included. The diagnosis was based on diplopia or ptosis as the main presenting symptom and anatomical location on the trajectory of the presumed cranial nerve of origin, or prior resection confirming diagnosis. Demographic, SRS dose planning, clinical, and imaging data were collected from chart review of the treated patients. Chi-square and Kaplan-Meier analyses were performed.

RESULTS

Seven institutions submitted data for a total of 25 patients. The median follow-up time was 41 months. The median age at the time of treatment was 52 years. There were 11 CN III schwannomas, 11 CN IV schwannomas, and 3 CN VI schwannomas. The median target volume was 0.74 cm3, and the median marginal dose delivered was 12.5 Gy. After SRS, only 2 patients (including the only patient with neurofibromatosis type 2) had continued tumor growth. Crude local control was 92% (23/25), and the 10-year actuarial control was 86%. Diplopia improved in the majority of patients (11/21), and only 3 had worsening following SRS, 2 of whom also had worsened ptosis, both in the context of tumor progression.

CONCLUSIONS

SRS for schwannomas of the oculomotor, trochlear, and abducens nerves is effective and provides tumor control rates similar to those for other cranial nerve schwannomas. SRS allows improvement of diplopia in the majority of patients. SRS should therefore be considered as a first-line treatment option for oculomotor nerve schwannomas.

Surgical management of intraoperatively diagnosed facial nerve schwannoma located at internal auditory canal and cerebellopontine angle - our experiences of 14 cases

BACKGROUND

Facial nerve schwannomas located at internal auditory canal and cerebellopontine angle (IAC/CPA FNS) were diagnosed intraoperatively, it poses a therapeutic dilemma to the surgeon.

OBJECTIVE

To report our experience in managing IAC/CPA FNS and to propose a treatment strategy.

METHODS

A total of 14 patients with IAC/CPA FNS who were diagnosed intraoperatively and treated by operation between 2015 and 2019 were retrospectively studied.

RESULTS

Unilateral hearing loss was the most common symptom and all these patients had normal facial nerve function preoperatively. Surgical approaches used in these patients including translabyrinthine (2 cases), retrosigmoid (RS) (11 cases), and middle cranial fossa (MCF) approach (1 case). Eight patients underwent partial resection, three patients underwent subtotal resection and three patients had complete tumor removal with facial nerve reconstruction. All partial resection patients and two patients underwent subtotal resection achieved a long-term HB grade I facial nerve function. The long-term facial nerve function of patients underwent complete resection and nerve grafting was no better than HB grade III.1 of the eight patients underwent partial resection experienced tumor regrowth during the follow-up.

CONCLUSIONS

Partial or subtotal resection for IAC/CPA FNS may provide an opportunity of retaining excellent facial nerve function. Regular postoperative imaging is helpful to monitor the recurrence.

Radiotherapy challenges in COVID era

The pandemic caused by the new coronavirus (SARS-CoV-2) associated with a disease named COVID-19 by the World Health Organization that began in late 2019 in Wuhan city has become a global public health problem. Only 2 months later, the new virus affected most countries of the world, the consequence being an overload of health systems, especially Intensive Care Units. Considered a category of patients at high risk of developing severe forms of the disease, cancer patients can develop a severe form of the disease, complicated by acute respiratory distress syndrome requiring mechanical ventilation. Radiotherapy, as a treatment included in the multidisciplinary management of cancer for both curative and palliative purposes, is also affected by the COVID-19 pandemic. COVID-19-positive or -suspected patients are a special category for which the decision to postpone treatment should be made based on the particularities of tumor biology and the radiobiological effect of a gap in radiation fractions delivery. Emergencies including spinal cord compressions, tumor bleeding, and brain metastases not responsive to corticosteroid treatment, should be considered a priority but the palliative treatment should be limited from one single fraction to maximum five fractions for spinal cord compression and whole brain radiotherapy. Radiotherapy for brain metastases does not bring a benefit in terms of overall survival for patients with life expectancy of days or weeks and dexamethasone treatment is the correct choice in this situation. In all settings, the approach of radiotherapy treatment must be adapted for both scenarios of an outbreak pandemic, when general measures of social distancing and protection by specific equipment of patients and radiotherapy staff are a priority, but also for a long period of coexistence with the virus with possible new “pandemic waves.”

A Case of Meningioma Originating from the Oculomotor Nerve

BACKGROUND

Schwannoma originating from the oculomotor nerve has been reported. However, meningioma originating from this nerve was unknown.

CASE DESCRIPTION

A 22-year-old woman presented with a unique case of meningioma originating from the oculomotor nerve manifesting as periorbital pain and diplopia beginning 4 months previously. Oculomotor nerve schwannoma was suggested by several pretreatment examinations. Tumor resection was considered risky for preservation of the oculomotor nerve function; therefore, gamma knife surgery (GKS) was performed. Six months later, she suffered right complete ptosis and worsened blurry vision. Corticosteroid was administered, but her symptoms did not improve. Magnetic resonance imaging showed the tumor lesion had grown larger. We decided to resect the tumor lesion because of her uncontrolled periorbital pain. The tumor had occupied the oculomotor cistern and was gross totally removed. Histologic diagnosis was surprisingly transitional meningioma. The tumor lesion occupied the oculomotor cistern and was refractory to GKS, with a progressive clinical course, which is more suggestive of meningioma than schwannoma, although extremely rare. Her periorbital pain and blurry vision gradually regressed, whereas complete oculomotor nerve palsy persisted.

CONCLUSIONS

In such a case, tumor resection after GKS should be considered.

Long-term results of Gamma Knife radiosurgery for facial nerve schwannomas

OBJECTIVE

Long-term outcomes of eleven cases of facial nerve schwannoma were evaluated and the related literature was reviewed to determine the efficacy of Gamma Knife radiosurgery for treating patients with facial nerve schwannoma.

METHODS

Eleven patients with facial nerve schwannoma (7 women and 4 men; mean age, 44.2 years; range, 19-73 years) underwent Gamma Knife radiosurgery. The most common symptoms were facial palsy (n = 10) and hearing loss (n = 7). Five patients presented with headache. Two patients had undergone prior resection. The patients' clinical and radiographic data were evaluated retrospectively.

RESULTS

For the 11 cases of facial nerve schwannoma, mean tumor volume was 3.1 cm³ (range, 0.4-7.4 cm³) and the mean marginal dose applied was 11.9 Gy (range, 11-13 Gy). The mean follow-up period was 84.3 months (range, 66-117 months). Tumor control was achieved in all patients. At the time of writing, four patients experienced tumor volume regression and the other seven were in stable condition. During follow-up, nine patients experienced no change in their facial function, two experienced deteriorated facial function, and none developed new facial palsy. Ten patients who had serviceable hearing prior to Gamma Knife radiosurgery retained their hearing.

CONCLUSIONS

Gamma Knife radiosurgery achieves excellent results with respect to tumor control for 7 years on average. In addition, Gamma Knife radiosurgery provides good results in facial nerve and hearing function at long term. Our series demonstrates that Gamma Knife radiosurgery is an effective and safe treatment for patients with either primary or residual facial nerve schwannoma.

Parasellar Schwannomas: Extradural vs Extra-Intradural Surgical Approach

BACKGROUND

Schwannomas of the parasellar region may arise from the trigeminal, oculomotor, trochlear, and abducens nerves.

OBJECTIVE

To define the tumor origin, location, and dural relationship (extradural vs extra-intradural vs cisternal) on preoperative magnetic resonance imaging (MRI), in order to plan the best surgical approach (purely extradural vs extra-intradural).

METHODS

Twenty-four patients with parasellar schwannomas who underwent surgery were retrospectively analyzed. Twenty arose from the trigeminal nerve (7 intracavernous and 13 within the Meckel's cave), 3 from the oculomotor nerve, and 1 from the abducens nerve. The preoperative identification of the tumor location (extradural vs extra-intradural vs cisternal) and the nerve of origin was defined on MR sequences. All patients were operated on through a pterional approach (extradural or extra-intradural route).

RESULTS

The tumor location was correctly defined on MRI in 22 out of 24 cases (92%) and the nerve of origin in 22 (92%). An extradural approach without intradural exploration was performed in all 5 intracavernous trigeminal schwannomas, in 11 out of 13 of the Meckel's cave, and in 2 schwannomas of the oculomotor nerve. Two schwannomas of the Meckel's cave with transgression of the medial dural wall, 1 of the oculomotor nerve, and the abducens nerve schwannoma required an extra-intradural approach. Complete tumor resection was obtained in 19 out of 24 cases (80%).

CONCLUSION

The pterional extradural approach is sufficient for Dolenc type I and II trigeminal schwannomas, excepting for those transgressing the inner dural layer. Schwannomas of the oculomotor and abducens nerves with cisternal location require an extradural-intradural approach.

Oculomotor Schwannomas: A Systematic Review and Report of Two Pediatric Cases Treated with Fractionated Cyberknife Stereotactic Radiotherapy

OBJECTIVE

Pediatric oculomotor nerve schwannomas are rare and challenging lesions due to the high morbidity associated with surgical intervention and their proximity to critical structures limiting the opportunity for stereotactic radiosurgery. We aim to report and review the novel use of fractionated Cyberknife (Accuray, Inc., Sunnyvale, California, USA) stereotactic radiotherapy in pediatric patients with oculomotor schwannomas.

METHODS

A systematic review of PubMed, Embase, and Cochrane was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Two patients, ages 8 and 10 years, with tumor volumes of 0.1 cm³ and 0.2 cm³, respectively, were treated with fractionated Cyberknife radiotherapy at our institution. A total dose of 45-50 Gy was administered over 25 fractions (1.8-2.0 Gy per fraction) to the 82%-84% isodose line. Serial magnetic resonance imaging was obtained for long-term follow-up (56-58 months).

RESULTS

We found 14 articles published between 1982 and 2018 that reported a total of 18 pediatric patients with intracranial oculomotor schwannomas. No previously described cases of pediatric intracranial oculomotor schwannomas were treated with radiation therapy. In both of our patients, radiographic tumor control was achieved at a mean follow-up of 57 months, with 1 patient displaying a decrease in tumor volume. Neither patient exhibited any worsening of their presenting symptoms, nor did either patient develop any new neurocognitive deficits following treatment.

CONCLUSIONS

Fractionated Cyberknife radiotherapy is an effective and well-tolerated treatment option for intracranial oculomotor nerve schwannomas with excellent tumor control rates, similar to surgical and radiosurgical techniques, while sparing critical surrounding structures.

Management of oculomotor nerve schwannoma: Systematic review of literature and illustrative case

Background:

Oculomotor nerve schwannoma (ONS) is an extremely rare intracranial benign tumor. Till date, there is no standard treatment of oculomotor schwannoma. Here, we present an illustrative case report of ONS, perform a systematic review of literature on surgically and radiosurgically treated cases and morbidity related to both treatment modalities.

Methods:

We performed a systematic review of literature for cases with ONS treated with surgery or radiosurgery using PubMed/Ovid Medline.

Results:

Till date, there are 60 reported cases of ONS (45 treated surgically and seven radiosurgically) with the dominance of female gender (53%) and mean age of 35.2 years (Range 1–66). In 8% of the cases, there was no involvement of cranial nerve (CN) III and 92% of the cases CN III alone or together with CN II, IV, V, and VI. In 67% of the cases a complete resection and 33% a partial resection performed. In 73% of the cases, postoperative third nerve palsy was documented, 22% improved after surgery and in around 5% of cases, the outcome was not described. In the radiosurgically treated cases of nonvestibular schwannoma including ONS, the progression-free interval of approximately 2 years was above 90%.

Conclusion:

Due to the high rate of postoperative complete oculomotor nerve palsy, a subtotal resection avoiding the nerve injury seems to be a feasible option. Radiosurgery is another option to treat small size schwannoma. A combined treatment with microsurgery followed by radiosurgery may allow effective treatment for large size oculomotor schwannoma.

Natural History, Multimodal Management, and Quality of Life Outcomes of Trigeminal Schwannomas

Background  Trigeminal schwannomas are the second most common among intracranial schwannomas. These can arise from anywhere between the root and the distal extracranial branches of the trigeminal nerve. Clinical presentation depends on location and size, including but not limited to facial hypesthesia or pain, headaches, dizziness, ataxia, and diplopia. Literature is strikingly scant discussing the natural history of these lesions, while the treatment goals are heavily dependent on tumor presentation. Management decisions must be individualized to each tumor and each patient, while attempting to maximize the quality of life. We present the natural history of these lesions as well as their management by surgical resection or radiation therapy, and report long-term quality of life outcomes. Methods  Between 2001 and 2015, 24 patients (66.7% female) with trigeminal schwannomas were diagnosed and managed at Vancouver General Hospital. We analyzed the clinical presentation, surgical results, resection rates, patient quality of life, and complications. To complete the evaluation, we prospectively collected 36-Item Short Form Health Survey (SF-36) quality of life assessments for comparison. Results  We identified 12 patients treated with a craniotomy and surgical resection, 4 were treated with radiation therapy, while 8 patients were followed by observation. Mean age of study cohort was 49.2 years (range, 23-79 years), and most patients presented with facial hypesthesia (54.2%) and headaches (37.5%), while 37.5% were incidental findings. There were no major differences in patient demographics between the three groups. Patients offered surgery had larger lesions (mean diameter, 3.4 ± 1.1 cm) when compared with those that were irradiated or observed, and were more likely to have extracranial extension. Overall patient quality of life improved following treatment (ΔSF-36 + 12.9) at 3.9 years. Conclusions  The treatment goals of trigeminal schwannomas focus on improvement in neurologic symptoms, relief of mass effect, and preservation of cranial nerve function. We demonstrate that smaller lesions found incidentally with minimal symptoms can be followed safely with serial imaging, with 1 of 9 (11.1%) progressing to require treatment over the course of 7.1 years. Management of trigeminal schwannomas should be individualized with an involvement of a multidisciplinary skull base team.

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.

Fractionated Radiation Therapy for Benign Nonacoustic Schwannomas

OBJECTIVES

We analyzed the outcomes of patients with benign nonacoustic schwannomas treated with fractionated radiation therapy (RT).

METHODS

Between October 1987 and March 2013, 11 patients with benign nonacoustic schwannomas diagnosed radiographically (n=3) or pathologically (n=8) were treated with fractionated RT with curative intent at the University of Florida. We reviewed patients' medical records to assess outcomes and toxicities from treatment.

RESULTS

The median follow-up for all patients was 8.2 years (range, 2.2 to 22.7 y) and 8 years for all living patients (range, 2.2 to 22.7 y). Of the 11 patients included in the analysis, 8 (73%) were treated solely with RT, 1 (9%) was treated with postoperative RT after subtotal resection, and 2 (18%) were treated with postoperative RT after recurrence following initial surgical resection. The 5-year overall survival, disease-free survival, and local control rates were 100%. There were no grade 2 to 5 treatment toxicities.

CONCLUSIONS

RT for benign nonacoustic schwannoma may be effective when used alone or in addition to surgery. Irradiation should be considered in patients for whom resection is likely to result in one or more neurological deficits. Fractionated RT to a total dose of 50 Gy provides excellent local control and minimal morbidity.

Radiosurgery in trochlear and abducens nerve schwannomas: case series and systematic review

INTRODUCTION

Schwannomas involving the occulomotor cranial nerves  (CNs; III, IV and VI), can be disabling, due to the associated diplopia and decreased quality of life and are extremely rare. We evaluated the role of Gamma Knife surgery (GKS) in these cases.

METHODS

Five patients with CN IV and VI schwannomas (three and two, respectively) were treated in Lausanne University Hospital between 2010 and 2015. Four benefitted from upfront GKS and one from a combined approach (planned subtotal resection followed by GKS), due to a large preoperative tumour volume (size, 3 × 2 × 2.5 cm; volume, 7.9 ml), with symptomatic mass effect and oedema, as well as an entrapement cyst at the brainstem interface, in a young patient. Neuro-ophtalmological evaluation was performed at baseline and during each follow-up time-point. A systematic literature review is presented and compared to the present report.

RESULTS

The mean follow-up was 44.4 months (12-54). Initial clinical presentation was diplopia in four cases and cavernous sinus syndrome in one. The marginal dose was 12 Gy in all cases. The mean target volume was 1.51 cm³ (0.086-5.8). The mean prescription isodose volume (PIV) was 1.71 cm³ (0.131-6.7). At last follow-up, all patients presented with disappearance of the baseline symptoms. Tumour control was achieved in 100%, with decrease in volume in all cases. The systematic review analysed 11 peer-reviewed studies, with a total of 35 patients. For uniformly reported CN VI, the mean marginal radiation dose ranged between 12 and 12.5 Gy, with disappearance of symptoms in 12.5%, improvement in 31.25%, stabilisation in 6.25%, worsening in 12.5%. Tumour volume decreased in all cases.

CONCLUSIONS

Our data suggest that first intention GKS is a safe and effective option for patients with small to medium size oculomotor schwannomas, providing a high rate of clinical alleviation and tumour control. When the initial tumour volume is too large for first intention GKS, a combined approach with planned subtotal resection followed by GKS can be performed, with favourable and comparable outcomes as in upfront GKS.

Analysis of risk factors to predict communicating hydrocephalus following gamma knife radiosurgery for intracranial schwannoma

Communicating hydrocephalus (HCP) in vestibular schwannomas (VS) after gamma knife radiosurgery (GKRS) has been reported in the literature. However, little information about its incidence and risk factors after GKRS for intracranial schwannomas is yet available. The objective of this study was to identify the incidence and risk factors for developing communicating HCP after GKRS for intracranial schwannomas. We retrospectively reviewed a total of 702 patients with intracranial schwannomas who were treated with GKRS between January 2002 and December 2015. We investigated patients' age, gender, tumor origin, previous surgery history, tumor volume, marginal radiation dose, and presence of tumor control to identify associations with communicating HCP following GKRS. To make predictive models of communicating HCP, we performed Cox regression analyses and constructed a decision tree for risk factors. In total, 29 of the 702 patients (4.1%) developed communicating HCP following GKRS, which required ventriculo-peritoneal (VP) shunt surgery. Multivariate analyses indicated that age (P = 0.0011), tumor origin (P = 0.0438), and tumor volume (P < 0.0001) were significant predictors of communicating HCP in patients with intracranial schwannoma after GKRS. Using machine-learning methods, we fit an optimal predictive model. We found that developing communicating HCP following GKRS was most likely if the tumor was vestibular origin and had a volume ≥13.65 cm³ . Communicating HCP is not a rare complication of GKRS for intracranial schwannomas. Under specific conditions, communicating HCP following GKRS is warranted for this patient group, and this patient group should be closely followed up.

Hypofractionated stereotactic radiotherapy for dumbbell-shaped hypoglossal schwannomas: Two cases of long-term follow-up and a review of the literature

Cases of hypoglossal schwannoma are extremely rare. Historically, microsurgical resection has been the standard treatment, but it may not always be feasible; thus, it is crucial to investigate alternative treatments. We herein present the cases of two patients, both of whom presented with tongue deviation and hemiatrophy, accompanied by headaches. Magnetic resonance imaging revealed a dumbbell-shaped tumor originating from the hypoglossal nerve that was adjacent to the cranial base in each patient. Hypofractionated stereotactic radiotherapy was used to treat the tumors, with a total dose of 30 Gy in 3-Gy fractions delivered to the planning target volume. Several months later, the tumors had significantly decreased in size and the symptoms of the two patients had gradually improved.

Multimodality Management of Trigeminal Schwannomas

Patients presenting with trigeminal schwannomas require multimodality management by a skull base surgical team that can offer expertise in both transcranial and transnasal approaches as well as radiosurgical and microsurgical strategies. Improvement in neurologic symptoms, preservation of cranial nerve function, and control of mass effect are the primary goals of management for trigeminal schwannomas. Complete surgical resection is the treatment of choice but may not be possible in all cases. Radiosurgery is an option as primary management for small- to moderate-sized tumors and can be used for postoperative residuals or recurrences. Planned surgical resection followed by SRS for residual tumor is an effective option for larger trigeminal schwannomas. The endoscopic resection is an excellent approach for patients with an extradural tumor or tumors isolated to the Meckel cave. A detailed analysis of a tumor and its surroundings based on high-quality imaging can help better estimate the expected outcome from each treatment. An expert skull base team should be able to provide precise counseling for each patient's situation for selecting the best option.

Gamma Knife surgery for patients with facial nerve schwannomas: a multiinstitutional retrospective study in Japan

OBJECT

The aim of this study was to explore the efficacy and safety of stereotactic radiosurgery for patients with facial nerve schwannomas (FNSs).

METHODS

This study was a multiinstitutional retrospective analysis of 42 patients with FNSs treated with Gamma Knife surgery (GKS) at 1 of 10 medical centers of the Japan Leksell Gamma Knife Society (JLGK1301). The median age of the patients was 50 years. Twenty-nine patients underwent GKS as the initial treatment, and 13 patients had previously undergone surgery. At the time of the GKS, 33 (79%) patients had some degree of facial palsy, and 21 (50%) did not retain serviceable hearing. Thirty-five (83%) tumors were solid, and 7 (17%) had cystic components. The median tumor volume was 2.5 cm3, and the median prescription dose to the tumor margin was 12 Gy.

RESULTS

The median follow-up period was 48 months. The last follow-up images showed partial remission in 23 patients and stable tumors in 19 patients. Only 1 patient experienced tumor progression at 60 months, but repeat GKS led to tumor shrinkage. The actuarial 3- and 5-year progression-free survival rates were 100% and 92%, respectively. During the follow-up period, 8 patients presented with newly developed or worsened preexisting facial palsy. The condition was transient in 3 of these patients. At the last clinical follow-up, facial nerve function improved in 8 (19%) patients, remained stable in 29 (69%), and worsened in 5 (12%; House-Brackmann Grade III in 4 patients, Grade IV in 1 patient). With respect to hearing function, 18 (90%) of 20 evaluated patients with a pure tone average of ≤ 50 dB before treatment retained serviceable hearing.

CONCLUSIONS

GKS is a safe and effective treatment option for patients with either primary or residual FNSs. All patients, including 1 patient who required repeat GKS, achieved good tumor control at the last follow-up. The incidence of newly developed or worsened preexisting facial palsy was 12% at the last clinical follow-up. In addition, the risk of hearing deterioration as an adverse effect of radiation was low. These results suggest that GKS is a safe alternative to resection.

Gamma Knife surgery for patients with jugular foramen schwannomas: a multiinstitutional retrospective study in Japan

OBJECTIVE This study aimed to explore the efficacy and safety of stereotactic radiosurgery in patients with jugular foramen schwannomas (JFSs). METHODS This study was a multiinstitutional retrospective analysis of 117 patients with JFSs who were treated with Gamma Knife surgery (GKS) at 18 medical centers of the Japan Leksell Gamma Knife Society. The median age of the patients was 53 years. Fifty-six patients underwent GKS as their initial treatment, while 61 patients had previously undergone resection. At the time of GKS, 46 patients (39%) had hoarseness, 45 (38%) had hearing disturbances, and 43 (36%) had swallowing disturbances. Eighty-five tumors (73%) were solid, and 32 (27%) had cystic components. The median tumor volume was 4.9 cm³, and the median prescription dose administered to the tumor margin was 12 Gy. Five patients were treated with fractionated GKS and maximum and marginal doses of 42 and 21 Gy, respectively, using a 3-fraction schedule. RESULTS The median follow-up period was 52 months. The last follow-up images showed partial remission in 62 patients (53%), stable tumors in 42 patients (36%), and tumor progression in 13 patients (11%). The actuarial 3- and 5-year progression-free survival (PFS) rates were 91% and 89%, respectively. The multivariate analysis showed that pre-GKS brainstem edema and dumbbell-shaped tumors significantly affected PFS. During the follow-up period, 20 patients (17%) developed some degree of symptomatic deterioration. This condition was transient in 12 (10%) of these patients and persistent in 8 patients (7%). The cause of the persistent deterioration was tumor progression in 4 patients (3%) and adverse radiation effects in 4 patients (3%), including 2 patients with hearing deterioration, 1 patient with swallowing disturbance, and 1 patient with hearing deterioration and hypoglossal nerve palsy. However, the preexisting hoarseness and swallowing disturbances improved in 66% and 63% of the patients, respectively. CONCLUSIONS GKS resulted in good tumor control in patients with either primary or residual JFSs. Although some patients experienced some degree of symptomatic deterioration after treatment, persistent adverse radiation effects were seen in only 3% of the entire series at the last follow-up. Lower cranial nerve deficits were extremely rare adverse radiation effects, and preexisting hoarseness and swallowing disturbances improved in two-thirds of patients. These results indicated that GKS was a safe and reasonable alternative to surgical resection in selected patients with JFSs.

Intratemporal facial nerve schwannoma: clinical presentation and management

Facial nerve schwannoma is the most common facial nerve tumor, but its therapeutic strategy remains debated. The aim of this study is to analyze the facial nerve function and the hearing outcomes after surgery or wait-and-scan policy in a facial nerve schwannoma series. A monocentric retrospective review of medical charts of patients followed for an intratemporal facial nerve schwannoma between 1988 and 2013 was performed. Twenty-two patients were included. Data were extracted pertaining to the following variables: patient demographics, tumor localization, clinical and imaging features, facial nerve function and hearing levels, and details of surgical intervention. The majority of tumors were located at the geniculate ganglion. Initial symptoms were mainly facial palsy and hearing loss. The average follow-up was 4.8 ± 4.5 years. Nineteen patients underwent surgery, and three patients were observed. After surgery, 11 patients had a stable or improved facial nerve function (57.9 %), and 8 patients had a worsened facial nerve function (42.1 %). Facial nerve function was in the majority of cases a HB grade III, depending on surgical strategy. No patient presented a postoperative HB grade V or VI. Regarding the hearing, it remained stable after surgery in 52.6 % of cases, and improved in 10.5 % of cases. Among monitored patients, facial nerve function and hearing remained stable. Surgery for facial nerve schwannoma is a safe and effective option in the treatment of these tumors.

Communicating Hydrocephalus Associated with Intracranial Schwannoma Treated by Gamma Knife Radiosurgery

OBJECTIVE

Gamma knife radiosurgery (GKRS) has been established as an effective and safe treatment for intracranial schwannoma. However, serious complications can occur after GKRS, including hydrocephalus. The pathophysiology and risk factors of this disorder are not yet fully understood. The objective of the study was to assess potential risk factors for hydrocephalus after GKRS.

METHODS

We retrospectively reviewed the medical radiosurgical records of 244 patients who underwent GKRS to treat intracranial schwannoma. The following parameters were analyzed as potential risk factors for hydrocephalus after GKRS: age, sex, target volume, irradiation dose, prior tumor resection, treatment technique, and tumor enhancement pattern. The tumor enhancement pattern was divided into 2 groups: group A (homogeneous enhancement) and group B (heterogeneous or rim enhancement).

RESULTS

Of the 244 patients, 14 of them (5.7%) developed communicating hydrocephalus. Communicating hydrocephalus occurred within 2 years after GKRS in most patients (92.8%). No significant association was observed between any of the parameters investigated and the development of hydrocephalus, with the exception of tumor enhancement pattern. Group B exhibited a statistically significant difference by univariate analysis (P = 0.002); this difference was also significant by multivariate analysis (P = 0.006).

CONCLUSION

Because hydrocephalus is curable, patients should be closely monitored for the development of this disorder after GKRS. In particular, patients with intracranial schwannomas with irregular enhancement patterns or cysts should be meticulously observed.

Fractionated Stereotactic Radiotherapy for Facial Nerve Schwannomas

Purpose Data on the clinical course of irradiated facial nerve schwannomas (FNS) are lacking. We evaluated fractionated stereotactic radiotherapy (FSRT) for FNS. Methods Eight consecutive patients with FNS treated at our institution between 1998 and 2011 were included. Patients were treated with FSRT to a median dose of 50.4 Gy (range: 46.8-54 Gy) in 1.8 or 2.0 Gy fractions. We report the radiographic response, symptom control, and toxicity associated with FSRT for FNS. Results The median follow-up time was 43 months (range: 10-75 months). All patients presented with symptoms including pain, tinnitus, facial asymmetry, diplopia, and hearing loss. The median tumor volume was 1.57 cc. On the most recent follow-up imaging, five patients were noted to have stable tumor size; three patients had a net reduction in tumor volume. Additionally, six patients had improvement in clinical symptoms, one patient had stable clinical findings, and one patient had worsened House-Brackmann grade due to cystic degeneration. Conclusion FSRT treatment of FNS results in excellent control of growth and symptoms with a small rate of radiation toxicity. Given the importance of maintaining facial nerve function, FSRT could be considered as a primary management modality for enlarging or symptomatic FNS.

Facial nerve schwannomas presenting as occluding external auditory canal masses: a therapeutic dilemma

OBJECTIVE

To present a series of patients with facial nerve schwannomas (FNSs) presenting as occluding external auditory canal (EAC) masses.

STUDY DESIGN

Retrospective case series.

PATIENTS

Four patients were identified with mastoid segment FNSs occluding the EAC. Three patients presented with conductive hearing loss (CHL), and the fourth presented with facial paralysis, later developing CHL.

INTERVENTION

One patient underwent conservative debulking, removing the EAC component only. Two patients were managed nonoperatively with periodic cleaning of entrapped keratin. The fourth patient received radiation therapy.

MAIN OUTCOME MEASURES

Facial nerve function, canal cholesteatoma formation, and hearing.

RESULTS

Among the patients managed with serial cleaning of entrapped keratin, one maintained normal facial function and one worsened to House-Brackmann II/VI. Facial function worsened to House-Brackmann II/VI in the patient who underwent surgical debulking. The fourth patient, who received radiation, developed complete facial paralysis. All patients accumulated keratin medial to the tumor, and all had CHL.

CONCLUSION

When evaluating an EAC tumor, it is important to obtain imaging before biopsy because biopsy of a schwannoma can result in paralysis. EAC occlusion by a schwannoma presents a challenging management issue, particularly when cholesteatoma forms between the tumor and the tympanic membrane. The primary goal is maintaining normal facial function as long as possible and avoiding secondary ear canal complications. The presence of canal occlusion limits the choice of stereotactic radiation because this leads to a month-long period of tumor swelling and cutaneous sloughing. Resection and grafting are indicated when substantial facial weakness or twitch develops.

Stereotactic radiosurgery for facial nerve schwannomas: meta-analysis and clinical review

OBJECTIVE

Although several small individual series on stereotactic radiosurgery (SRS) for facial nerve schwannomas (FNSs) have been published, we aim to systematically aggregate data from the literature as well as from our institution to better understand the safety and efficacy of SRS for FNS.

DATA SOURCES

PubMed English language search for keywords "facial nerve schwannoma" AND "radiation therapy" published from January 1995 to 2014. Data from our institution were also included in the analysis.

STUDY SELECTION

Minimum study inclusion criteria included tumor treatment outcomes yielding 10 studies in the literature. In addition, our institution's data on six patients were included.

DATA EXTRACTION

Data included radiation treatment type, radiation dose, tumor size, tumor control, tumor control definition, FN function, hearing outcome, and duration of follow-up.

DATA SYNTHESIS

In total, there were 45 patients with at least 2-year follow-up. Forty-two patients (93.3%) had tumor control. Of those patients with described growth/shrinkage definitions, 50.0% had no growth, 43.3% had shrinkage, and 6.7% had growth. Of those articles that included FN functional outcomes, 26 patients (66.6%) had stable FN function, 8 (20.5%) had improved function, and 5 (12.8%) had worsened FN function after treatment. In total, there were 30 patients whose hearing outcomes were discussed in the literature. Of those with serviceable hearing before SRS (n = 14), nine (64.3%) had stable hearing and five (36.7%) had worsened function after SRS. The mean posttreatment follow-up period was 42.1 months.

CONCLUSION

SRS seems to be effective at either stabilizing or shrinking FNS. However, significant morbidities of FN paralysis hearing loss do exist.

Primary tumors of the facial nerve

This article describes the pathophysiology, diagnosis, treatment, and outcomes of primary tumors of the facial nerve. These tumors include facial nerve schwannomas, geniculate ganglion hemangiomas, glomus facialis, and granular cell tumors. Although these tumors are rare, collected data help to form a consensus with regard to optimal treatment methods.

Gamma Knife surgery for facial nerve schwannomas

OBJECT

The aim of this study was to evaluate the tumor control rate and functional outcomes after Gamma Knife surgery (GKS) among patients with a facial nerve schwannoma.

METHODS

The authors reviewed the radiological data and clinical records for 14 patients who had consecutively undergone GKS for a facial nerve schwannoma. Before GKS, 12 patients had facial palsy, 7 patients had hearing disturbance, and 5 patients had undergone partial or subtotal tumor resection. The mean and median tumor volumes were 3707 mm(3) and 3000 mm(3), respectively (range 117-10,100 mm(3)). The mean tumor margin dose was 13.2 Gy (range 12-15 Gy), and the mean maximum tumor dose was 26.4 Gy (range 24-30 Gy). The mean follow-up period was 80.7 months (range 2-170 months).

RESULTS

Control of tumor growth was achieved in all 12 (100%) patients who were followed up for longer than 2 years. After GKS, facial nerve function improved in 2 patients, remained unchanged in 9 patients, and worsened in 3 patients. All patients who had had serviceable hearing at the preliminary examination maintained their hearing at a useful level after GKS. Other than mild tinnitus reported by 3 patients, no other major complications developed.

CONCLUSIONS

GKS for facial nerve schwannomas resulted in excellent tumor control rates and functional outcomes. GKS might be a good primary treatment option for patients with a small- to medium-sized facial nerve schwannoma when facial nerve function and hearing are relatively preserved.

Facial nerve schwannoma: A case report and review of the literature

A vestibular schwannoma, often termed an acoustic neuroma, is a type of benign primary intracranial tumor of the myelin-forming cells of the vestibulocochlear nerve. The typical clinical presentation often includes ipsilateral sensorineural hearing loss/deafness, vertigo and tinnitus. In the present study, the case of a young male patient who presented with recurrent unilateral facial palsy without hearing impairment is presented. The patient was diagnosed with vestibular schwannoma and received steroidal treatment with prednisolone for two weeks. The patient’s facial weakness recovered three weeks following treatment, however, the tumor subsequently grew. The patient then underwent Gamma Knife radiosurgery with a margin dose of 13 Gy. Six months after the radiosurgery, the tumor was stable without progression, and the patient’s facial nerve function and hearing remained intact.

Intraoperatively diagnosed cerebellopontine angle facial nerve schwannoma: how to deal with it

OBJECTIVE

This study aimed to report our experience in the management of patients with intraoperatively diagnosed intracranial facial nerve schwannomas (FNSs) and propose a decision-making strategy.

METHODS

Twenty-three patients with FNS of the internal auditory canal and/or cerebellopontine angle operated on between 1992 and 2012 were identified.

RESULTS

Preoperatively, all cases have been radiographically diagnosed as vestibular schwannomas. Operative procedures consisted of total tumor resection with grafting in 43.4% of patients, near-total resection leaving behind the tumor capsule overlying the facial nerve in 21.7%, total tumor resection with preservation of anatomic continuity of the facial nerve in 13%, and subtotal resection in 4.3%. Four patients (17.4%) underwent bony decompression with no tumor removal.

CONCLUSION

Management of FNS diagnosed at surgery represents a significant clinical challenge. We considered total tumor resection with grafting when patients presented with preoperative facial nerve palsy (≥ grade III). Both subtotal and near-total tumor removal can be performed in patients with preoperative good facial function and/or large tumors with brainstem compression. Patients with small tumors who were selected for hearing preservation surgery can be considered for bony decompression. Fascicle preservation surgery may be an option when a clear cleavage plane between the tumor and the facial nerve is found.

A schwannoma of the greater petrosal nerve located within the petrous apex and treated with stereotactic radiotherapy

A 26 year-old female experienced progressive left sided pulsatile tinnitus and conductive hearing loss for two years, which following an extensive clinical workup, was diagnosed as a left greater petrosal nerve schwannoma located within the petrous apex of the temporal bone. Between neurosurgical management and radiation therapy, multiple therapeutic options were presented to the patient, who ultimately chose stereotactic radiotherapy as an alternative to surgical resection due to the potential morbidity associated with surgery. The patient received three fractions of 600 cGy without subsequent worsening of her symptoms, new onset neurologic symptoms or radiation induced side effects reported at a 3, 6 and 12 month clinic visits. A follow-up MRI at 6 and 12 months post radiation administration demonstrated no further tumor growth.

Facial nerve schwannomas of the cerebellopontine angle: the mayo clinic experience

Background There is often controversy regarding the optimal management for patients with facial nerve schwannomas (FNSs) of the cerebellopontine angle (CPA). Methods The clinical and radiological outcomes in 14 patients with CPA FNS were retrospectively reviewed. Results Patients underwent resection with anatomic nerve preservation (n = 3), facial-hypoglossal nerve anastomosis (n = 4), gamma knife radiosurgery (GKS) (n = 6), or observation (n = 1). A total of 83% of tumors that underwent GKS were stable or decreased in size. No patient who underwent resection showed evidence of tumor recurrence; the tumor under observation remained unchanged with normal facial function at the time of the last follow-up. Facial function was decreased in 57%, stable in 14%, and improved in 29% of those who underwent microsurgery. A total of 67% of patients who underwent GKS had stable facial function. Serviceable hearing was maintained in 50% of patients in the GKS group and 67% of the tumor resection group. Mean and median follow-up was 48 and 43 months, respectively (range, 12 to 95 months). Conclusion Observation should be the primary management when encountered with FNS of the CPA in those with good neurologic function. Microsurgery or radiosurgery may be used in those with poor facial function or tumor progression.

Intra-parotid facial nerve schwannoma with intra-temporal extension; a case report. Is there a role for stereotactic radiotherapy?

Facial nerve schwannoma (FNS) is an extremely rare benign tumour that may arise anywhere along the course of the facial nerve; the standard treatment is total removal via microsurgery. Stereotactic radiotherapy has been shown to be effective in the treatment of skull base tumours, in particular for acoustic neuromas; it is interesting to notice that also the few data existing in literature about the use of radiotherapy for non acoustic schwannomas show an excellent local control rate and few adverse effects. Here we report a case of facial nerve neuroma, involving the nerve sheath from the geniculate ganglion to the parotid gland, treated with fractionated stereotactic radiotherapy after debulking surgery.

Are the current treatment strategies for facial nerve schwannoma appropriate also for complex cases?

OBJECTIVES

To describe the decision-making strategies for complex facial nerve schwannomas (FNSs).

MATERIALS AND METHODS

Charts belonging to 103 consecutive patients with facial nerve tumors managed between 1990 and 2011 were examined retrospectively to identify complex FNSs. To be classified as complex, at least one of the following criteria had to be met: (1) FNS with large intraparotid tumor component and preoperative good facial nerve function (3 cases); (2) multiple-segment FNSs with extension to both the cerebellopontine angle and the middle cranial fossa in patients with preoperative good hearing (5 cases); (3) fast-growing FNS with preoperative good facial nerve function (4 cases), and (4) large FNS compressing the temporal lobe with preoperative normal facial nerve function (1 case).

RESULTS

Thirteen patients were classified as complex; 12 patients had total tumor removal with sural nerve grafting and 1 patient had partial tumor removal. Two patients with intratemporal-intraparotid FNS underwent a transmastoid-transparotid approach. One patient with a tumor extending from the geniculate ganglion to the parotid portion of the facial nerve underwent a combined middle fossa transmastoid-transparotid approach. A transcochlear approach with temporal craniotomy was performed in all the patients with multiple-segment FNS as well as in patients with fast-growing tumors extending both in the cerebellopontine angle and middle cranial fossa. A partial tumor removal through the middle fossa approach was performed in 1 patient with a large tumor compressing the temporal lobe.

CONCLUSIONS

Therapeutic options for patients with FNS include surgical intervention, observation and radiotherapy. Nowadays, surgical resection with facial nerve repair is usually the standard management for patients with poor facial function (House-Brackmann grade III or worse). In patients presenting with normal or near-normal facial nerve function, initial observation with periodic examination and imaging is usually recommended. However, on rare occasions surgeons can be faced with a situation in which the management decision-making process is particularly challenging. In these complex cases treatment should be individualized. We recommend early surgical intervention regardless of the preoperative facial and hearing functions in the following cases: intratemporal FNSs extending with a large tumor component into the parotid, multiple-segment FNSs extending in both the cerebellopontine angle and the middle cranial fossa, fast-growing FNSs, and large FNSs with temporal lobe compression.

Stereotactic Radiotherapy for Trigeminal Schwannomas

BACKGROUND:

Data on radiotherapy for trigeminal schwannomas (TSs) and comparison of stereotactic radiosurgery (SRS) with fractionated stereotactic radiotherapy (FSRT) are limited.

OBJECTIVE:

We present a large retrospective review of our institutional experience treating TSs with SRS and FSRT. We also describe a flare phenomenon experienced by some patients.

METHODS:

The records of 23 consecutive TSs patients treated with radiotherapy between 1996 and 2011 were reviewed. We investigated radiographic response, tumor control, and toxicity.

RESULTS:

Ten patients underwent SRS and 13 underwent FSRT, with median clinical follow-up of 32 months (range, 3–120 months). Tumor control at 5 and 10 years was 94% overall. Symptom control at 5 years was achieved in 48% of all patients, with nonsignificant improvement in more patients in the FSRT group than those in the SRS group (56% vs 40%, P = .37). Acute toxicity was higher in the FSRT group (38.5 vs 0%, P &lt; .01), although lesions treated with FSRT were larger (mean, 9.5 mL vs 4.8 mL, P &lt; .01). A symptomatic flare phenomenon occurred in 2 patients (8.7% overall) during FSRT, involving transient cystic formation and dramatic size increase. One lesion regressed in size and 1 remained stable on follow-up.

CONCLUSION:

Tumor control rates for TSs are excellent with SRS and FSRT with minimal toxicity. This represents the first documented report of a flare phenomenon after FSRT for TS treatment. Flare risk after FSRT in previously resected large lesions should be discussed with patients before treatment, and prophylactic oral steroids may be considered.

Gamma knife radiosurgery for jugular foramen schwannomas

Jugular foramen schwannomas are very rare tumors. Advances in skull base surgery have led to more aggressive resection of these tumors, but surgery may associate with development of new neurological deficits. In this report, we analyze the long-term results for 17 patients with newly diagnosed or residual/recurrent jugular foramen schwannoma who underwent gamma-knife treatment. During a mean 64 months of follow-up, magnetic resonance imaging revealed reduced tumor size in 13 cases and no size change in four cases. The tumor growth control rate was 100% and only one patient had transient hoarseness. For patients who have small- to moderate-sized jugular foramen schwannomas, gamma-knife radiosurgery is associated with good tumor control and carries minimal risk of adverse radiation effects.

Gamma Knife surgery for nonvestibular schwannomas: radiological and clinical outcomes

OBJECT

Most intracranial schwannomas arise from cranial nerve (CN) VIII. Stereotactic radiosurgery is a mainstay of treatment for vestibular schwannomas. Intracranial schwannomas arising from other CNs are much less common. We evaluate the efficacy of Gamma Knife surgery on nonvestibular schwannomas including trigeminal, hypoglossal, abducent, facial, trochlear, oculomotor, glossopharyngeal, and jugular foramen tumors.

METHODS

Thirty-six patients with nonvestibular schwannomas were treated at the University of Virginia Gamma Knife center from 1989 to 2008. The median patient age was 48 years (mean 45.6 years, range 10-72 years). Schwannomas arose from the following CNs: CN III (in 1 patient), CN IV (in 1), CN V (in 25), CN VI (in 2), CN VII (in 1), CN IX (in 1), and CN XII (in 3). In 2 patients, tumors arose from the jugular foramen. The median tumor volume was 2.9 cm(3) (mean 3.3 cm(3), range 0.07-8.8 cm(3)). The median margin dose was 13.5 Gy (range 9.3-20 Gy); the median maximum dose was 30 Gy (range 21.7-50.0 Gy).

RESULTS

The mean and median follow-up times of 36 patients were 54 and 37 months, respectively (range 2-180 months). At the last radiological follow-up, the tumor size had decreased in 20 patients, remained stable in 9 patients, and increased in 7 patients. The 2-year actuarial progression-free survival was 91%. Higher maximum dose was statistically related to tumor control (p = 0.027). Thirty-three patients had adequate clinical follow-up. Among them, 21 patients had improvement in their presenting symptoms, 8 patients were stable after treatment with no worsening of their presenting symptoms, 2 patients developed new symptoms, and 1 patient experienced symptom deterioration. Notably, 1 patient with neurofibromatosis Type 2 developed new symptoms that were unrelated to the tumor treated with Gamma Knife surgery.

CONCLUSIONS

Gamma Knife surgery is a reasonably effective treatment option for patients with nonvestibular schwannomas. Patients require careful follow-up for tumor progression and signs of neurological deterioration.

Evolution in the management of facial nerve schwannoma

OBJECTIVE

To design a treatment algorithm based on experience with facial nerve schwannomas (FNS) over a 30-year period.

STUDY DESIGN

Retrospective chart review.

METHOD

Seventy-nine patients with facial nerve schwannomas seen from 1979 through 2009 at a tertiary referral private otologic practice were categorized by treatment modality. Interventions included surgical resection with grafting, bony decompression, observation, or stereotactic radiation. Outcome measures included House-Brackmann facial nerve grade before and after intervention as well as change in facial nerve grade, tumor size, involved segments of nerve, time to intervention.

RESULTS

Thirty-seven patients (46.8%) ultimately underwent surgical excision with grafting or primary anastomosis, 21 (26.6%) underwent bony decompression alone, 15 (19.0%) were managed with observation only, and 6 (7.6%) had stereotactic radiation. Through 1995, 85% of cases had surgical resection and none had observation only. Of the 52 patients seen after 1995, 27% had surgical resection and grafting, 33% had bony decompression, 29% were managed with observation alone, and 11% had radiotherapy. Facial nerve grade was maintained or improved over the follow-up period (mean time = 3.9 years) in 78.9% of the decompression group and 100% of the observation and radiation groups compared to 54.8% of the resection group (P ≤ .012).

CONCLUSIONS

Surgical resection and grafting, once widely accepted and practiced, has in many cases given way to observation, bony decompression, or stereotactic radiation. A wide armamentarium of options is available to the neurotologist treating facial nerve schwannomas with the ability to preserve facial function for a longer period of time.

Management of oculomotor nerve schwannomas in two different locations: surgical nuances and comprehensive review

Rare tumors with anecdotal reportage, oculomotor schwannomas are most often seen in the oculomotor cistern close to the anterior clinoidal region. Adding to the small series of reported cases of this unusual lesion, we report two male patients in their second decade who presented with different degrees of oculomotor palsy. The location of the lesion was caverno-cisternal in one case and orbito-cavernous in the other. Intricate neurovascular relationships of this lesion, especially in non-cavernous locations, are discussed. The risk of damage to nerve rootlets enmeshed within the lesion is high with attempts at near-total excision, rendering the anatomical preservation of the nerve an arduous exercise. The authors review literature pertaining to this unusual lesion and elucidate surgical nuances which may have a bearing on outcome.

Stereotactic Radiosurgery of Cranial Nonvestibular Schwannomas: Results of Single- and Multisession Radiosurgery

BACKGROUND:

Surgical resection of nonvestibular cranial schwannomas carries a considerable risk of postoperative complications. Stereotactic radiosurgery (SRS) offers a non-invasive treatment alternative. The efficacy and safety of multi-session SRS of nonvestibular cranial schwannomas has not been well studied.

OBJECTIVE:

To analyze the results of single- and multi-session SRS of nonvestibular cranial schwannomas.

METHODS:

From 2001 to 2007, 42 lesions in 40 patients were treated with SRS at Stanford University Medical Center, targeting schwannomas of cranial nerves IV (n = 1), V (n = 18), VII (n = 6), X (n = 5), XII (n = 2), jugular foramen (n = 8), and cavernous sinus (n = 2). SRS was delivered to a median marginal dose of 18 Gy (range, 15-33 Gy) in 1 to 3 sessions, targeting a median tumor volume of 3.2 cm3 (range, 0.1-23.7 cm3). The median doses for treatments in 1 (n = 18), 2 (n = 9), and 3 (n = 15) sessions were 17.5, 20, and 18 Gy, respectively.

RESULTS:

With a median follow-up of 29 months (range, 6-84 months), tumor control was achieved in 41 of the 42 lesions. Eighteen of 42 lesions (43%) decreased in size; 23 tumors (55%) remained stable. There were 2 cases of new or worsening cranial nerve deficits in patients treated in single session; no patient treated with multi-session SRS experienced any cranial nerve toxicity (P = 0.18).

CONCLUSION:

SRS of nonvestibular cranial schwannomas provides excellent tumor control with minimal risk of complications. There was a trend towards decreased complications with multi-session SRS.

Vitamin D deficiency in the absence of enteropathy in three cases with common variable immunodeficiency

BACKGROUND

Common variable immunodeficiency (CVID) is characterized by hypogammaglobulinemia and a defect in antibody production. Herein we describe 3 patients diagnosed with CVID in whom vitamin D deficiency was detected in the absence of enteropathy.

METHODS

Biochemical and immunological analysis, serum osteocalcin, parathyroid hormone, 25-OH vitamin D, 1,25(OH)(2) vitamin D, vitamin A, vitamin E, urinary calcium, and deoxypyridinoline measurements were carried out. Vitamin D receptor (VDR) expression was examined in the peripheral blood mononuclear cells and hair follicles by reverse transcriptase polymerase chain reaction. VDR gene polymorphism was evaluated by high-performance liquid chromatography.

RESULTS

None of the patients presented nutrient deficiencies other than vitamin D. Two of them were free of osteomalacia-related symptoms. VDR expression was found to be lower in the peripheral blood mononuclear cells and hair follicles when compared to the control group.

CONCLUSIONS

Patients with CVID may present asymptomatic vitamin D deficiency. Vitamin D and VDRs play an important role in the innate immune system and modulate Toll-like receptor-related responses. Delay in diagnosis may predispose these patients not only to irreparable bone loss but also to infections, and autoimmune and malignant disorders, thus emphasizing the importance of prompt intervention.