Benign Skull Base Tumors Research Articles

Dosimetric Comparison of Between Multileaf and Fixed Cone Collimator Plans with Cyberknife-M6 in the Benign Skull Base Tumors

Dosimetric Comparison of Between Multileaf and Fixed Cone Collimator Plans with Cyberknife-M6 in the Benign Skull Base Tumors

Adaptive Hybrid Surgery Experiences in Benign Skull Base Tumors.

Background: The treatment of benign skull base tumors remains challenging. These tumors are often located in close relationship to critical structures. Therefore, radical resection of these tumors can be associated with high morbidity. Multimodal treatment concepts, including controlled partial tumor resection followed by radiosurgery, should be considered. Methods: Adaptive hybrid surgery analysis (AHSA) is an intraoperative tool that has been introduced for the automatic assessment of tumor properties, and virtual real-time radiosurgical treatment simulation and continuous feasibility analysis of adjuvant radiosurgery. The AHSA method (Brainlab®, Munich, Germany) was applied to five patients who underwent partial resection of a benign skull base tumor. Tumor volumetry was obtained on pre- and postoperative MR scans. Organs at risk were, preoperative, automatically delineated with atlas mapping software (Elements® Segmentation Cranial), and adaptations were made if necessary. Results: Five patients with benign skull base lesions underwent planned partial tumor resection in a multimodal therapeutic surgery followed by radiosurgery. The preoperative tumor volumes ranged between 8.52 and 25.2 cm3. The intraoperative residual tumor volume measured with the AHSA® software ranged between 2.13–12.17 cm3 (25–52% of the preoperative tumor volume). The intraoperative automatic AHSA plans of the remaining tumor volume suggested, in all five patients, that safe hypofractionated radiation was feasible. Patients were followed for 69.6 ± 1.04 months, and no complications occurred after the patients were treated with radiation. Conclusions: Intraoperative SRS planning based on volumetric assessments during resection of skull base tumors using AHSA® is feasible and safe. The AHSA method allows the neurosurgeon to continuously evaluate the feasibility of adjuvant radiosurgery while planning and performing a surgical resection. This method supports the treatment strategy of a complementary approach during surgical resection of complex skull base tumors and might contribute to preventing surgical and radiosurgical complications.

Surgical Strategy of Benign Skull Base Tumors Based on Membrane Structure

Meningiomas, schwannomas, and pituitary adenomas are typically benign tumors of intracranial origin, but all of these tumors have a border with the surrounding tissue. The basic structure is a clear "boundary" between the tumor and its surroundings, with a thin membrane layer to create that separation. This layer of membrane is the boundary between the tumor and its surroundings and provides a space for the tumor to grow its cells, and can be viewed as the so-called "tumor capsule. Based on the relationship between the membrane structure of the tumor capsule and the surrounding normal tissues, we perform surgery to reduce surgical complications. We histologically evaluated three types of tumor capsules(meningioma, schwannoma, and pituitary adenoma)and compared the membrane structure of each tumor with that seen in clinical surgery.

Advances and future directions in the care of patients with facial paralysis

Advances and future directions in the care of patients with facial paralysis

The relation between serum vitamin D deficiency and allergic rhinosinusitis

Introduction Endonasal endoscopic approaches gained acceptance in managing many benign skull base tumors. Cerebrospinal fluid (CSF) leak is a common and serious complication with high risk of morbidities or mortality. Identification and management of intraoperative CSF leak is a critical step in these approaches. Various methods and materials had been described for a skull base reconstruction. The size of arachnoid defect plays a crucial role in selecting the proper method of reconstruction. Patients and methods This is a prospective analytical study in which 67 patients with benign skull base lesions who were candidates for endoscopic transnasal transsphenoid surgery were included. All cases were subjected to detailed assessment protocol preoperatively and postoperatively. Intraoperative CSF leak was meticulously observed and graded according to the size of arachnoid defect, and then reconstruction was done according to grade of CSF leak by grafts or flaps or combination of them. Results This study included 67 patients with sellar–suprasellar tumors who were managed by endoscopic transsphenoid approach. Intraoperative CSF leak occurred in 23 (34.3%) cases. A total of nine (13.4%) cases had grade 1 CSF leak, and all cases were reconstructed with abdominal fat with success rate of 100%;six (8.9%) cases had grade 2 CSF leaks, and all cases were repaired with pedicled nasal flap with success rate (83%); and grade 3 CSF leak occurred in eight (11.9%) cases, and all were repaired with multilayer technique, with success rate of 75%. The incidence of postoperative CSF leak in this study was 4.5%, that is, three patients. Conclusion The strategy of skull base reconstruction depending on grade of intraoperative CSF leak according to size of arachnoid defect produces a promising result in decreasing the incidence of postoperative CSF leak and saving the need of unnecessary flaps. Keywords: arachnoid defect, reconstruction, sella, skull base.

P03.14 New features of modern 3D conformal external radiotherapy (RT) of benign head tumors in children

Abstract BACKGROUND demonstrate the possibilities of radiation therapy (LT) in children with benign head tumors using IMRT, VMAT, IGRT techniques - high-precision modern 3D conformal radiation therapy MATERIAL AND METHODS From 1990 to 2007 for the first time in Russia, 88 children with juvenile angiofibromas were treated in Russian Scientific Center of Roentgenoradiology. The studies were carried out on the gamma-therapeutic apparatus “AGAT-P1” and on the linear accelerator “Phillips SL75” Total dose was 35–45 Gy. In 2014–2018 we treated 29 patients aged 3–17 years with benign tumors of the skull base and brain (angiofibromas, craniopharyngiomas, hemangiomas) using high-precision techniques (IMRT, VMAT, IGRT). 15 of 29 patients were repeatedly operated in various domestic and foreign clinics and were admitted to RT with the threat of bleeding, with recurrent growth of tumors, including after multiple selective angioembolization. RESULTS Up to 80% of patients had a 5-year stable remission, and the optimal total dose for radiation therapy of benign head tumors in children was scientifically substantiated. It was found that there is a high risk of continued growth after RT in children under 8 years of age, complications in 10% of patients in the coming years after RT and in 100% of those reirradiated. In all 29 cases of RT in children, we observed a positive clinical effect - stopping bleeding from the nasopharynx after 1–3 sessions of 3D conformal RT (Dose per fraction 1.8 Gy, total dose 45–54 Gy), positive clinical symptoms under the supervision of an Head and Neck surgeon. The effect of hardening and stopping the growth of tumors according to MRI data were followed up after 3 months, 6 months, 1 year. CONCLUSION The development of navigational, endosurgical and fibro-endoscopic minimally invasive technologies in the last 30 years has allowed to expand the indications for surgical methods of treatment for benign head tumors in children, which has reduced their flow to RT. However, after modern surgical interventions, 6–10% of these patients experience recurrences and bleeding, the number of which can be reduced with timely RT. New technologies in LT provide minimal impact on surrounding healthy tissues and allow wider use of RT in recurrent and difficult-to-reach benign skull base tumors in children

Quality of Life in Jugular Paraganglioma Following Radiosurgery.

The treatment paradigm for jugular paraganglioma (JP) has changed considerably over time with the wider adoption of stereotactic radiosurgery (SRS). To the best of the authors' knowledge, there are no published studies that use validated patient-reported outcome measures to ascertain quality of life (QoL) outcomes following SRS for JP when used in single or combined modality treatment regimens. Cross-sectional survey. Tertiary referral center. Adult patients with JP treated with primary SRS or SRS following primary surgery between 1990 and 2017. Surgery and/or Gamma Knife SRS. Global and treatment-related QoL and differences in QoL based on treatment approach. Sixty-nine surveys were distributed and a total of 26 completed surveys were received (38% response rate). Among respondents, the median age at SRS was 53 years and 16 of the 26 patients (62%) were female. Median follow-up was 97 months. Nineteen patients (73%) were treated with primary SRS or staged SRS following intentional subtotal resection (STR; hereafter referred to as "staged SRS"), while the remainder (n = 7, 27%) were treated with SRS for recurrent JP. Median physical and mental health QoL PROMIS-10 T-scores regardless of treatment strategy were 39.8 and 38.8, respectively, while median SF36 physical and mental component subscores were similar to national averages and non-tumor controls. When comparing general physical and mental health QoL scores, there was no significant difference between patients treated with primary or staged SRS and those treated with SRS for recurrent JP. However, age-adjusted swallowing function among patients treated with primary or staged SRS was better than in those patients treated with SRS for recurrent JP (p = 0.05). Patients treated with primary or staged SRS for JP tend to exhibit better swallowing outcomes than those treated with SRS for recurrent JP. However, the majority of overall and disease-specific quality of life measures were not different between groups. Based on the low incidence of new cranial neuropathy following SRS, it is likely that initial surgical morbidity is the primary contributor to this outcome. Disease-specific overall quality of life measures, akin to those already used for other benign skull base tumors, are necessary to better gauge physical and mental health outcomes following treatment for JP. Though limited by small sample size, this represents the first study to gauge QoL outcomes following treatment for JP.

P05.37 Hypofractionated radiosurgery for benign skull base tumors

P05.37 Hypofractionated radiosurgery for benign skull base tumors

Clinical efficacy and safety of surface imaging guided radiosurgery (SIG-RS) in the treatment of benign skull base tumors.

Frameless, surface imaging guided radiosurgery (SIG-RS) is a novel platform for stereotactic radiosurgery (SRS) wherein patient positioning is monitored in real-time through infra-red camera tracking of facial topography. Here we describe our initial clinical experience with SIG-RS for the treatment of benign neoplasms of the skull base. We identified 48 patients with benign skull base tumors consecutively treated with SIG-RS at a single institution between 2009 and 2011. Patients were diagnosed with meningioma (n = 22), vestibular schwannoma (n = 20), or nonfunctional pituitary adenoma (n = 6). Local control and treatment-related toxicity were retrospectively assessed. Median follow-up was 65 months (range 61-72 months). Prescription doses were 12-13Gy in a single fraction (n = 18), 8Gy × 3 fractions (n = 6), and 5Gy × 5 fractions (n = 24). Actuarial tumor control rate at 5 years was 98%. No grade ≥3 treatment-related toxicity was observed. Grade ≤2 toxicity was associated with symptomatic lesions (p = 0.049) and single fraction treatment (p = 0.005). SIG-RS for benign skull base tumors produces clinical outcomes comparable to conventional frame-based SRS techniques while enhancing patient comfort.

Clinical Efficacy and Safety of Surface Imaging Guided Radiosurgery in the Treatment of Benign Skull Base Tumors

Frameless, surface imaging guided radiosurgery (SIG-RS) is a novel platform for stereotactic radiosurgery (SRS) wherein patient positioning is monitored in real-time through infra-red camera tracking of facial topography. Here we describe our initial clinical experience with SIG-RS for the treatment of benign neoplasms of the skull base. We identified 48 patients with benign skull base tumors consecutively treated with SIG-RS at a single institution between 2009 and 2011. Patients were diagnosed with meningioma (n = 22), vestibular schwannoma (n = 20), or nonfunctional pituitary adenoma (n = 6). Local control and treatment-related toxicity were retrospectively assessed. Median follow-up was 65 months (range 61–72 months). Prescription doses were 12–13 Gy in a single fraction (n = 18), 8 Gy × 3 fractions (n = 6), and 5 Gy × 5 fractions (n = 24). Actuarial tumor control rate at 5 years was 98%. No grade ≥3 treatment-related toxicity was observed. Grade ≤2 toxicity was associated with symptomatic lesions (p = 0.049) and single fraction treatment (p = 0.005). SIG-RS for benign skull base tumors produces clinical outcomes comparable to conventional frame-based SRS techniques while enhancing patient comfort.

Endoscope-Assisted Microsurgery in Petroclival Meningioma Combined with Contralateral Trigeminal Schwannoma

Objectives: To introduce a rare case of bilaterally developed skull base tumor and surgical tactics to remove the mass with endoscope assistant. Patient: A 46-year-old female patient presented with facial numbness for 2 months. She showed decreased facial sensory change and pterygoid muscle weakness. Brain magnetic resonance image (MRI) revealed round well demarcating mass on left petroclival area. The size was 4 × 5cm, extending from the internal acoustic canal to the midbrain. It showed well homogenous enhancement and dural tail sign. There was another mass on the contralateral infratemporal fossa. It originates from Meckels cavum and extends to the infratemporal fossa. Digital subtraction angiography revealed rare vascularization around both the tumors. Result: Anterior petrosal approach was done to the petroclival mass. Invisible site with microscope was examined with endoscope. Total removal was done without any complication. Pathology report was meningioma. Subtemporal approach was performed instead of usual infratemporal fossa approach with the aid of endoscope, which provides a nice view about the invisible site with a microscope. Conclusion: We could successfully remove benign skull base tumors with the aid of endoscope by minimal-invasive approach.

Validation of Outcome Measurements in Surgically Treated Vestibular Schwannomas

Introduction: Surgical resection of benign skull base tumors carries risk of postoperative morbidity. With decrease in morbidity and mortality, concerns and expectations for surgery have changed. In this scenario it is essential to assess risk of postoperative morbidity and incapacity. In the present study, we have validated different outcome tools with preoperative factors. Patients and Methods: A total of 167 patients from a retrospective and a prospective cohort who underwent microsurgical resection for vestibular schwannomas between 2001 and 2010 were surveyed. Preoperative variables such as age, gender, tumor size, and neurological symptoms were assayed against different outcome measures such as QOL work capacity/independency (actual work capacity, Karnovsky, independency), facial function (HB and SB), neurological score (patients and physicians score) in univariate and multivariate analysis. Results: All outcome measures except Eq. 5D showed a significant decrease postoperatively. Only HB grade differed significantly between the cohorts with a better score in the prospective cohort. Patient assessed neurological score correlated significantly to all other outcome measures. Conclusion: Standard QOL instruments may not be sensitive enough to measure outcome after surgery of benign skull base tumors, work capacity is useful in younger patients but patient assessed morbidity may be more useful in all patients.

Long-term Evaluation of Radiation-Induced Optic Neuropathy After Single-Fraction Stereotactic Radiosurgery

To determine the long-term risk of radiation-induced optic neuropathy (RION) inpatients having single-fraction stereotactic radiosurgery (SRS) for benign skull base tumors. Retrospective review of 222 patients having Gamma Knife radiosurgery for benign tumors adjacent to the anterior visual pathway (AVP) between 1991 and 1999. Excluded were patients with prior or concurrent external beam radiation therapy or SRS. One hundred twenty-nine patients (58%) had undergone previous surgery. Tumor types included confirmed World Health Organization grade 1 or presumed cavernous sinus meningioma (n=143), pituitary adenoma (n=72), and craniopharyngioma (n=7). The maximum dose to the AVP was ≤8.0 Gy (n=126), 8.1-10.0 Gy (n=39), 10.1-12.0 Gy (n=47), and >12 Gy (n=10). The mean clinical and imaging follow-up periods were 83 and 123 months, respectively. One patient (0.5%) who received a maximum radiation dose of 12.8 Gy to the AVP developed unilateral blindness 18 months after SRS. The chance of RION according to the maximum radiation dose received by the AVP was 0 (95% confidence interval [CI] 0-3.6%), 0 (95% CI 0-10.7%), 0 (95% CI 0-9.0%), and 10% (95% CI 0-43.0%) for patients receiving ≤8 Gy, 8.1-10.0 Gy, 10.1-12.0 Gy, and >12 Gy, respectively. The overall risk of RION in patients receiving >8 Gy to the AVP was 1.0% (95% CI 0-6.2%). The risk of RION after single-fraction SRS in patients with benign skull base tumors who have no prior radiation exposure is very low if the maximum dose to the AVP is ≤12 Gy. Physicians performing single-fraction SRS should remain cautious when treating lesions adjacent to the AVP, especially when the maximum dose exceeds 10 Gy.

Proton beam therapy for intracranial and skull base tumors

Radiotherapy is widely used for treating malignant and benign intracranial or skull base tumors because of the difficulty in performing wide or complete tumor resection due to the involvement of eloquent areas, vital vessels, or cranial nerves. Similarly, local radiotherapy with conventional methods may sometimes be inefficient for treating brain tumors because the tolerance doses for the optic nerves, eyes, and brainstem are strictly limited. Under the circumstances, particle radiotherapy with proton or carbon ion beams has excellent dose localization to the target volume owing to the sharp Bragg peak ionization in the human body. With this property, it is possible to deliver higher doses to tumors of various shapes while preserving the surrounding critical brain structures. Although the efficacy of proton beam therapy (PBT) has been suggested for skull base chordoma and unresectable meningioma, further clinical evidence is required for optimization and standardization of the therapy. In refractory tumors such as glioblastoma multiforme and anaplastic meningioma, it is necessary to deliver high doses to improve tumor control. Under these circumstances, protons or carbon ions have potential to deliver sufficient doses to the target while keeping the healthy brain intact. In this context, we focus on the current status of proton beam radiotherapy for treating intracranial and skull base tumors.

Adaptive Hybrid Surgery: Feasibility of Planned Subtotal Resection of Benign Skull Base Tumors Followed by Radiosurgery to Minimize Morbidity Without Compromising Tumor Control

Adaptive Hybrid Surgery: Feasibility of Planned Subtotal Resection of Benign Skull Base Tumors Followed by Radiosurgery to Minimize Morbidity Without Compromising Tumor Control

Planned Subtotal Resection in Benign Skull Base Tumors Followed by Gamma Knife Surgery: Preliminary Results

Planned Subtotal Resection in Benign Skull Base Tumors Followed by Gamma Knife Surgery: Preliminary Results

A Critical Analysis of the Literature Review in “Stereotactic Radiosurgery for Trigeminal Pain Secondary to Benign Skull Base Tumors” by Tanaka et al. and Presentation of an Algorithm for Management of These Tumors

A Critical Analysis of the Literature Review in “Stereotactic Radiosurgery for Trigeminal Pain Secondary to Benign Skull Base Tumors” by Tanaka et al. and Presentation of an Algorithm for Management of These Tumors

Clinical outcome after Hypofractionated Stereotactic Radiotherapy (HSRT) for benign skull base tumors

Objective: Surgical resection of skull base tumors can be associated with significant morbidity. In cases where the risks outweigh the benefits, radiation therapy can offer an alternative means to effectively control tumor growth. However, the optimal dose regime for radiation therapy remains controversial. The objective of this study was to assess the neurological outcome, local control rate and morbidity associated with a 5-fraction regime of hypofractionated stereotactic radiotherapy (HSRT) for benign skull base tumors.Methods: Twenty-six patients presenting with two of the most prevalent benign skull base tumors were included in the study. The tumors comprised 16 meningiomas and 10 acoustic neuromas. All patients exhibited preserved cranial nerve function prior to treatment, and a detailed audiological assessment was performed pre- and post-treatment for those patients with acoustic neuroma. Stereotactic radiosurgery was administered with the frameless CyberKnife Robotic Radiosurgery System. In each case, a 5-fraction HSRT regime was used: a dose of 5 Gy × 5 = 25 Gy to 6 Gy × 5 = 30 Gy was prescribed for skull base meningiomas, and 5 Gy × 5 = 25 Gy was prescribed for acoustic neuromas.Results: The clinical and radiographic median follow-up was 22 months (range: 6-54 months). Radiological assessment showed local control in all 26 tumors (100%), and in 5/26 patients (20%) the tumor showed a decrease in size. Cranial nerve function was preserved in all cases thus far studied; however, 28% of patients had transient Grade II side effects, including fatigue, headaches, unsteadiness and transient subjective worsening of hearing. In two of these patients, the period of transient worsening of hearing was associated with a temporary increase in the size of the tumor on control T2 MR images, consistent with radiation-induced edema. One patient had transient decrease in visual acuity from treatment-related edema. At the last follow-up, 3/16 patients with meningiomas (19%) and 2/10 with acoustic neuromas (20%) showed a decrease in tumor volume and improvement in hearing.Conclusion: A 5-fraction stereotactic radiotherapy regime, as used in this study, seems to be effective for local control of benign skull base tumors in this early follow-up evaluation. Neurological function preservation is excellent with this short regime in the early post-treatment period, but long-term follow-up is crucial for validation.

Stereotactic radiation treatment of vestibular schwannoma: indications, limitations, and outcomes

Stereotactic radiation treatment is an increasingly performed procedure for patients with vestibular schwannoma and other benign skull base tumors. During the past 30 years, advancements in stereotactic imaging, radiation delivery techniques, and dose planning have improved overall patient outcomes. The specific role of radiation in current management strategies for vestibular schwannoma continues to evolve as long-term outcome data are analyzed and standardized studies are performed. The recent literature regarding the indications, limitations, and outcomes for stereotactic radiation treatment is reviewed. Systematic reviews of the Gamma Knife literature demonstrate improved overall outcomes with radiation doses below 13 Gy. Observation of small vestibular schwannomas is recommended over early radiation or microsurgical intervention. Radiation may be used as adjunctive therapy for large tumors and in certain postradiation treatment failures. Stereotactic radiosurgery and fractionated radiotherapy are equally effective treatment modalities. Long-term outcome data will ultimately define future indications and limitations for the use of stereotactic radiation with benign skull base lesions. Current evidence supports its use for small to medium sized primary and recurrent vestibular schwannomas with optimal dosing below 13 Gy. It is also recommended for adjunctive therapy, recurrent tumors, in poor surgical candidates, and for those who do not desire observation or surgery.

Gamma Knife Radiosurgery for Benign Tumors With Symptoms From Brainstem Compression

This study evaluated the role of radiosurgery in the management of symptomatic patients with brainstem compression from benign basal tumors. Over a 17-year, period 246 patients (202 vestibular schwannomas and 44 meningiomas) with brainstem compression from benign skull-base tumors were managed with Gamma Knife radiosurgery. Median tumor volumes were 3.9 cm(3) (range, 0.8-39.0 mL) and 6.6 mL (range, 1.6-25.1 mL) for vestibular schwannomas and meningiomas, respectively. For both tumors, a median marginal dose of 13 Gy was prescribed. Median follow-up of patients was 65 months for vestibular schwannomas and 60 months for meningiomas. Patients were categorized into four groups on the basis of the tumor-brainstem relationship on neuroimaging. Preservation of function was stratified according to grade of brainstem compression. We analyzed the effect of radiosurgery on symptoms of brainstem compression. The tumor control rate was 100 % for meningioma and 97% for vestibular schwannomas (although 5% required an additional procedure such as a ventriculoperitoneal shunt). In patients with vestibular schwannoma, serviceable hearing was preserved in 72.0%. Balance improved in 31.9%, remained unchanged in 56.5%, and deteriorated in 11.6% of patients who had imbalance at presentation. Balance improved significantly in patients who had less tumor compression (p = 0.0357) after radiosurgery. Symptoms improved in 43.2% of patients with meningioma. Radiosurgery is a minimally invasive option for patients with benign basal tumors that indent or distort the brainstem. A high tumor growth control rate and satisfactory rate of neurological preservation and symptom control can be obtained with radiosurgery.