Small Skull Base Research Articles

Surgical Treatment of Symptomatic Small Medial Petrous Meningiomas Causing Trigeminal Neuralgia

Symptomatic trigeminal neuralgia caused by small (<3 cm) skull base meningiomas is treated by radiosurgery or surgical resection. Although radiosurgery is less invasive, surgical resection provides more rapid resolution of symptoms. We reviewed a short series of patients who underwent an anterior transpetrosal approach for surgical resection of meningiomas causing trigeminal neuralgia. A retrospective review of 5 consecutive patients with meningiomas causing trigeminal neuralgia of the senior author was included. Preoperative parameters (size, proximity to critical neurovascular structures, presence of brainstem compression), intraoperative parameters (Simpson grade of resection, loss of brainstem evoked potentials, surgical approach), and outcomes (symptom resolution, extent of resection, follow-up) were recorded. Patient median age was 67 years (range, 60-73 years). All patients had symptoms concerning trigeminal neuralgia with 2 having associated areas of facial numbness. The anterior transpetrosal approach was used to achieve complete resection (Simpson grade I). Postresection, the trigeminal nerve and brainstem were clearly visible to evaluate neurovascular structures and ensure decompression. No postoperative complications were reported, and all patients experienced sustained symptomatic relief 1 month postsurgery. With the advent of radiosurgery for skull base meningiomas, surgical resection is not always considered; however, such meningiomas causing trigeminal neuralgia can be resected safely using the anterior transpetrosal approach allowing rapid resolution of symptoms. This review of operative nuances provides aguide for neurosurgeons to provide safe surgical resection.

"Parachute" Technique for Reconstruction of Small Skull Base Defects of the Ventral Skull Base.

"Parachute" Technique for Reconstruction of Small Skull Base Defects of the Ventral Skull Base.

Private domestic well water as a possible source of lead exposure in three rural illinois counties: a pilot study

Minimally invasive surgery of small skull base meningiomas is technically challenging. We report the role of endoscopic 5-aminolevulinic acid fluorescence guidance (e-5-ALA-FGS) for small and deep-seated anterior skull base meningiomas.We report the cases of 2 patients. The first case was a small olfactory groove meningioma resected via a trans-eyebrow, subfrontal approach. The second case was a clinoid meningioma with invasion of the optic canal resected via a small frontolateral approach. Intraoperative documentation demonstrated the usefulness of 5-ALA endoscopy. In either case, residual fluorescing tumor tissue was detected. No complication was encountered. The clinical and radiological outcomes were good. No regrowth had occurred after 54 and 17 months of follow-up, respectively.Residual meningioma tissue on the far side of a keyhole approach (e.g., in the olfactory groove or at the optic canal) can be difficult to visualize. Visualization can be improved by use of an endoscope. To date, fluorescence guidance with a microscope was limited by insufficient fluorescence signals in deep corridors. With a specially equipped 5-ALA fluorescence endoscope, one can combine the advantages of both endoscopic vision and fluorescence guidance. The results of present report have demonstrated the usefulness of 5-ALA endoscopy for difficult to visualize areas.Endoscopic 5-ALA fluorescence guidance was shown to be feasible when resecting small and deep-seated skull base meningiomas via minimally invasive approaches. Based on this proof of principle, we encourage its evaluation for the middle or posterior fossa (e.g., internal auditory canal) and other difficult areas (e.g., behind neurovascular structures or the brainstem). The sensitivity and specificity of this method should be prospectively and systematically investigated.

P.268 Quetiapine ir for psychogenic non-epileptic seizures in a patient with schizophrenia: a case report

Symptomatic trigeminal neuralgia caused by small (<3 cm) skull base meningiomas is treated by radiosurgery or surgical resection. Although radiosurgery is less invasive, surgical resection provides more rapid resolution of symptoms. We reviewed a short series of patients who underwent an anterior transpetrosal approach for surgical resection of meningiomas causing trigeminal neuralgia.A retrospective review of 5 consecutive patients with meningiomas causing trigeminal neuralgia of the senior author was included. Preoperative parameters (size, proximity to critical neurovascular structures, presence of brainstem compression), intraoperative parameters (Simpson grade of resection, loss of brainstem evoked potentials, surgical approach), and outcomes (symptom resolution, extent of resection, follow-up) were recorded.Patient median age was 67 years (range, 60–73 years). All patients had symptoms concerning trigeminal neuralgia with 2 having associated areas of facial numbness. The anterior transpetrosal approach was used to achieve complete resection (Simpson grade I). Postresection, the trigeminal nerve and brainstem were clearly visible to evaluate neurovascular structures and ensure decompression. No postoperative complications were reported, and all patients experienced sustained symptomatic relief 1 month postsurgery.With the advent of radiosurgery for skull base meningiomas, surgical resection is not always considered; however, such meningiomas causing trigeminal neuralgia can be resected safely using the anterior transpetrosal approach allowing rapid resolution of symptoms. This review of operative nuances provides a guide for neurosurgeons to provide safe surgical resection.

Patient Outcomes after Reirradiation of Small Skull Base Tumors using Stereotactic Body Radiotherapy, Intensity Modulated Radiotherapy, or Proton Therapy.

Purpose The aim of this study was to evaluate outcomes of patients who received reirradiation for small skull base tumors utilizing either intensity modulated radiotherapy (IMRT), stereotactic body radiotherapy (SBRT), and proton radiotherapy (PRT). Methods Patients who received IMRT, SBRT or PRT reirradiation for recurrent or new small skull base tumors (< 60 cc) between April 2000 and July 2016 were identified. Those with < 3 months follow-up were excluded. Clinical outcomes and treatment toxicity were assessed. The Kaplan-Meier method was used to estimate the local control (LC), regional control (RC), distant control (DC), progression free survival (PFS), and overall survival (OS). Results Of the 75 patients eligible, 30 (40%) received SBRT, 30 (40%) received IMRT, and 15 (20%) received PRT. The median retreatment volume was 28 cc. The median reirradiation dose was 66 Gy in 33 fractions for IMRT/PRT, and 45 Gy in 5 fractions for SBRT. The median time to reirradiation was 41 months. With a median follow-up of 24 months, the LC, RC, DC, PFS, and OS rates were 84%, 79%, 82%, 60%, and 87% at 1 year, and 75%, 72%, 80%, 49%, and 74% at 2 years. There was no difference in OS between radiation modalities. The 1- and 2-year late Grade 3 toxicity rates were 3% and 11% respectively.. Conclusions Reirradiation of small skull base tumors utilizing IMRT, PRT, or SBRT provided good local tumor control and low rates of Grade 3 late toxicity. A prospective clinical trial is needed to guide selection of radiation treatment modalities.

Surgery of Small Anterior Skull Base Meningiomas by Endoscopic 5-Aminolevulinic Acid Fluorescence Guidance: First Clinical Experience

Minimally invasive surgery of small skull base meningiomas is technically challenging. We report the role of endoscopic 5-aminolevulinic acid fluorescence guidance (e-5-ALA-FGS) for small and deep-seated anterior skull base meningiomas. We report the cases of 2 patients. The first case was a small olfactory groove meningioma resected via a trans-eyebrow, subfrontal approach. The second case was a clinoid meningioma with invasion of the optic canal resected via a small frontolateral approach. Intraoperative documentation demonstrated the usefulness of 5-ALA endoscopy. In either case, residual fluorescing tumor tissue was detected. No complication was encountered. The clinical and radiological outcomes were good. No regrowth had occurred after 54 and 17 months of follow-up, respectively. Residual meningioma tissue on the far side of a keyhole approach (e.g., in the olfactory groove or at the optic canal) can be difficult to visualize. Visualization can be improved by use of an endoscope. To date, fluorescence guidance with a microscope was limited by insufficient fluorescence signals in deep corridors. With a specially equipped 5-ALA fluorescence endoscope, one can combine the advantages of both endoscopic vision and fluorescence guidance. The results of present report have demonstrated the usefulness of 5-ALA endoscopy for difficult to visualize areas. Endoscopic 5-ALA fluorescence guidance was shown to be feasible when resecting small and deep-seated skull base meningiomas via minimally invasive approaches. Based on this proof of principle, we encourage its evaluation for the middle or posterior fossa (e.g., internal auditory canal) and other difficult areas (e.g., behind neurovascular structures or the brainstem). The sensitivity and specificity of this method should be prospectively and systematically investigated.

Reirradiation of Small Skull Base Tumors: A Comparison of Patient Outcomes after Stereotactic Body Radiotherapy, Intensity-Modulated Radiotherapy, and Proton Therapy

Reirradiation of Small Skull Base Tumors: A Comparison of Patient Outcomes after Stereotactic Body Radiotherapy, Intensity-Modulated Radiotherapy, and Proton Therapy

Cranial Nerve Disorders in Children: MR Imaging Findings

Cranial nerve disorders are uncommon disease conditions encountered in pediatric patients, and can be categorized as congenital, inflammatory, traumatic, or tumorous conditions that involve the cranial nerve itself or propagation of the disorder from adjacent organs. However, determination of the normal course, as well as abnormalities, of cranial nerves in pediatric patients is challenging because of the small caliber of the cranial nerve, as well as the small intracranial and skull base structures. With the help of recently developed magnetic resonance (MR) imaging techniques that provide higher spatial resolution and fast imaging techniques including three-dimensional MR images with or without the use of gadolinium contrast agent, radiologists can more easily diagnose disease conditions that involve the small cranial nerves, such as the oculomotor, abducens, facial, and hypoglossal nerves, as well as normal radiologic anatomy, even in very young children. If cranial nerve involvement is suspected, careful evaluation of the cranial nerves should include specific MR imaging protocols. Localization is an important consideration in cranial nerve imaging, and should cover entire pathways and target organs as much as possible. Therefore, radiologists should be familiar not only with the various diseases that cause cranial nerve dysfunction, and the entire course of each cranial nerve including the intra-axial nuclei and fibers, but also the technical considerations for optimal imaging of pediatric cranial nerves. In this article, we briefly review normal cranial nerve anatomy and imaging findings of various pediatric cranial nerve dysfunctions, as well as the technical considerations of pediatric cranial nerve imaging. Online supplemental material is available for this article. (©)RSNA, 2016.

Development of a Skull Base Center in a Low-Volume Environment

Introduction: Endoscopic endonasal surgery of the cranial base is one of the more advanced surgical techniques with the aim of minimizing postoperative morbidity in patients with certain skull base pathology. At the University Medical Center Maribor, Department of Otolaryngology, we started with endoscopic surgery of sinonasal tumors and small skull base lesions in 2004. Gradual progression to management of more extensive and complex skull base pathology was made in 2010. Since Slovenia has only 2 million inhabitants and skull base pathology is scarce, a completely new training model and contemporary technology needed to be used to ensure patient safety and minimize complications.

A review of stereotactic radiosurgery practice in the management of skull base meningiomas.

Gross total resection of skull base meningiomas poses a surgical challenge due to their proximity to neurovascular structures. Once the gold standard therapy for skull base meningiomas, microsurgery has been gradually replaced by or used in combination with stereotactic radiosurgery (SRS). This review surveys the safety and efficacy of SRS in the treatment of cranial base meningiomas including 36 articles from 1991 to 2010. SRS produces excellent tumor control with low morbidity rates compared with surgery alone for asymptomatic small skull base meningiomas, patients with risk factors precluding conventional surgery, and as adjuvant therapy for recurrent or residual lesions.

Tension pneumocephalus as a result of endonasal surgery: an uncommon intracranial complication

Tension pneumocephalus (TP) is a clinical entity characterized by continued build-up of air within the cranial cavity, leading to abnormal pressure exerted upon the brain and subsequent neurologic deterioration, due to development of a mass effect and potentially a herniation syndrome. Intracranial complications of endoscopic sinus surgery (ESS) and other endonasal procedures are fortunately very rare, occurring in less than 3% of cases. We report 4 cases of small bone defects (<3 mm) in the anterior cranial base accompanied by TP, caused by ESS and other endonasal procedures. The pathophysiology and management of this clinical entity is discussed with a pertinent literature. Four patients with small (<3 mm) skull base defects were identified. All patients presented with active cerebrospinal fluid leaks. CT scans showed intracranial tension pneumocephalus. Using image-guided endoscopic techniques, all defects were addressed with multi-layer repair. Closure was achieved in all patients on the first attempt, with an average follow-up of 36 months. Tension pneumocephalus is a rare event that can occur as a result of traumatic or iatrogenic violation of the dura and should be considered in all patients presenting with altered mental status after endoscopic sinus surgery or other surgical and diagnostic procedures that violate either the cranial or spinal dura. Because of the potential for rapid clinical deterioration and death, prompt brain imaging is warranted to rule out the diagnosis, and urgent neurosurgical consultation is indicated for definitive management.

Una técnica simple y segura para el tratamiento de las rinolicuorreas por pequeños defectos: colgajo libre de superposición «overlay» de mucosa nasal

Cerebrospinal fluid leaks to the sinonasal cavities (rhinoliquorrhoea) represent a process with diagnostic and therapeutic difficulties. The endoscopic transnasal approach is the method of choice, but with many possible variants. The purpose of this paper was to make a critical review of our diagnostic and therapeutic protocol used for 11years. We operated on 31patients. The diagnosis was based on the biochemical analysis of rhinorrhoea, CT and MRI. endoscopic nasal surgery after preoperative intrathecal injection of 5% fluorescein (2cc). Closure was performed using a free overlay graft from middle turbinate mucosa. Two patients had meningitis as the first sign. All patients were diagnosed by biochemical analysis of rhinorrhoea. CT and MRI gave clear evidence of the leakage location. The skull base defect was always less than 1cm. Fluorescein allowed clear visualisation of the fistulous area without other instruments and produced no side effects. One patient had a postoperative frontal abscess, which evolved favourably. All fistulas were closed and there was only one recurrence at 10years, which debuted as pneumococcal meningitis. Our surgical protocol, based on the use of intrathecal fluorescein and free grafting of middle turbinate mucosa overlay onto the fistulous area, achieves successful long-term results in the management of rhinoliquorrhoea secondary to small skull base defects.

Abstract LB-227: Pilot clinical trials of FSPG (BAY 94-9392): An 18F-labeled glutamate derivative for PET imaging of system xC- activity in tumors

Abstract Visualizing adaptations of tumor metabolism by employing positron emission tomography (PET) with a specific imaging probe has the potential to better characterize tumors with higher sensitivity and specificity. The glutamate-cystine exchanger (system xC-, a SLC7A11/SLC3A2 heterodimer) is an important transporter in tumor cells and a promising new target for imaging. This exchanger transports the amino acids L-cystine and L-glutamate, thus providing a rate-limiting precursor for glutathione biosynthesis. This contributes to redox maintenance, which is especially important in tumor cells. Recently, it was reported that a splice variant of the stem cell marker CD44 stabilizes the xCT subunit of system xC- at the cell membrane and promotes its proper function. FSPG (BAY 94-9392) is an 18F-labeled glutamate derivative that provides specific visualization of system xC- activity with PET/CT. Through this multicenter pilot trial, FSPG has successfully been translated into cancer patients and shows favorable pharmacokinetics and an absence of adverse events. A favorable biodistribution pattern previously seen in mice was also confirmed in these patients with different tumor types. A high lesion detection rate (80-100%) was found in lung cancer (n=10), hepatocellular cancer (n=5), head and neck cancer (n=5), and colorectal cancer (n=5) patients who also had positive FDG-PET/CT scans. Importantly, very low background uptake in healthy brain parenchyma enabled the detection of high-grade brain cancers as well as small brain metastases and skull base lesions (n=4) not well seen with FDG-PET. Primary breast tumors (n=4) and a low-grade brain tumor, however, showed minimal uptake of FSPG. Immunohistochemical (IHC) analyses on these subjects’ pathology samples showed significant correlation between FSPG uptake and protein expression of both the xCT subunit and CD44. In breast tumor samples specifically, IHC showed that absence of CD44 results in low signal from FSPG-PET even if xCT is present, indicating the importance of CD44 co-expression for system xC- function. Future clinical studies will further explore the potential of this compound in additional tumor types and expand upon the initial findings in a larger number of subjects. Here we present the first clinical examples demonstrating the ability of the tracer to measure system xC- activity in patients. FSPG-PET/CT may provide improved characterization and sensitivity of tumor detection in patients and further improve the understanding of the role of system xC- in cancer biology. It could be a valuable tool for improved tumor classification in patients, linking uptake of the tracer with malignancy and cancer stem cell properties of tumors. Furthermore, the ability to noninvasively probe this important pathway in humans may allow for more rational treatment planning, patient stratification and better development of new drugs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-227. doi:1538-7445.AM2012-LB-227

Deliberate Design of the Posterior Septectomy during Transsphenoidal Endoscopic Skull Base Surgery to Harvest Septal Tissue for Potential Skull Base Reconstruction

Background: The use of autologous free bone and mucosal grafts in reconstructing small skull base defects not requiring the nasoseptal flap is well described. A posterior septectomy is routinely performed during transsphenoidal endoscopic skull base surgery. However, formal planning of the septectomy to harvest septal tissue (free mucosal and bone grafts) for skull base reconstruction has not been described.

Die transnasale Route zur Schädelbasis. Von der Nasennebenhöhlenchirurgie zur Schädelbasischirurgie

The indications for endonasal endoscopic approaches to diseases of the skull base and its adjacent structures have expanded considerably during the last decades. This is not only due to improved technical possibilities such as intraoperative navigation, the development of specialized instruments, and the compilation of anatomical studies from the endoscopic perspective but also related to the accumulating experience with endoscopic procedures of the skull base by multidisciplinary centers. Endoscopic endonasal operations permit new approaches to deeply seated lesions and are characterized by a reduced manipulation of neurovascular structures and brain parenchyma while at the same time providing improved visualization. They reduce the trauma caused by the approach, avoid skin incisions and minimize the surgical morbidity. Transnasal endoscopic procedures for the closure of small and large skull base defects have proven to be reliable and more successful than operations with craniotomies. The development of new local and regional vascularized flaps like the Hadad-flap have contributed to this. These reconstructive techniques are furthermore effectively utilized in tumor surgery in this region. This review delineates the classification of expanded endonasal approaches in detail. They provide access to lesions of the anterior, middle and partly also to the posterior cranial fossa. Successful management of these complex procedures requires a close interdisciplinary collaboration as well as continuous education and training of all team members.

The Superior Turbinate Osteoplastic Flap: A New Vascularized Flap for Repair of the Anterior Skull Base

Introduction: Traditionally, repairs of spontaneous skull base defects have relied on local or free mucosal and free bone grafts for closure. Free grafting is highly successful for small skull base defects, with a low incidence of postoperative cerebrospinal fluid (CSF) leaks. With larger defects, a vascularized flap has been shown to be more effective in reducing CSF leak rates to those similar to open repair. Previously described techniques include a nasoseptal flap, a pedicled inferior turbinate flap, and a middle turbinate mucosal flap. The use of the superior turbinate for repair of defects has limited description in otolaryngology and neurosurgery literature. We describe the use of the superior turbinate as an osteoplastic flap for repair of an anterior skull base defect after endoscopic endonasal resection of a cribriform encephalocele.

Long-Term Outcome of Endonasal Endoscopic Skull Base Reconstruction with Nasal Turbinate Graft

To study the long-term outcome of endonasal endoscopic skull base reconstruction with nasal turbinate tissue free graft. This study included 55 consecutive patients who underwent endonasal endoscopic skull base reconstruction with nasal turbinate graft and were available for follow-up. They were 30 patients with pituitary adenomas, 20 with cerebrospinal fluid (CSF) rhinorrhea of different etiologies, three with meningoencephalocele, and two with skull base meningiomas. Autologous nasal turbinate tissue materials were used in reconstructing the skull base defect. Clinical follow-up with endoscopic nasal examination was done routinely 1, 3, 6, and 12 months after surgery. Computed tomography and magnetic resonance imaging were performed when indicated. The follow-up period ranged from 6 months to 8 years. There were no major operative or postoperative complications. Nasal turbinate graft was effective in sealing of intraoperative CSF leak, obliteration of dead space, and anatomic reconstruction of the skull base. There was no evidence of graft migration or inflammatory changes. Starting from 3 months after surgery to the rest of the follow-up period, endonasal endoscopic view of the site of duraplasty showed that: with small skull base defect (less than 5 mm), there was neither dural pulsation nor prolapse; with moderate-sized defect (5 to 10 mm), there was dural pulsation without prolapse; with larger defect (> 10 mm), there was dural pulsation and prolapse. These finding were constant regardless of the etiology of the lesion and the reconstruction material used. This long-term study demonstrated the efficacy of nasal turbinate graft in sealing of CSF leak without any delayed complications. Other rigid materials may be considered in reconstruction of large skull base defect (more than 10 mm) to prevent dural prolapse and herniation. For any future endonasal procedure for those patients, who had previous endonasal endoscopic duraplasty, the surgeons should be fully aware of the state of duraplasty (e.g., dural prolapse) to avoid any intraoperative complication (e.g., penetration of the prolapsed dura during nasal packing).

Utility of Preoperative High-Resolution CT and Intraoperative Image Guidance in Identification of Cerebrospinal Fluid Leaks for Endoscopic Repair

Endoscopic repair of cerebrospinal fluid (CSF) leaks is a well-established procedure. The radiological workup and use of intraoperative image guidance (IGS), lumbar drain (LD), and intrathecal fluorescein (IF) are less universally accepted. This study examines endoscopic repair of CSF leaks using preoperative high-resolution CT (HRCT) and intraoperative IGS without IF or LD. Retrospective review was performed of a single surgeon experience between September 2002 and January 2007. Forty-two anterior skull base defects in 40 patients were repaired endoscopically. The etiology of CSF leaks was traumatic in 5, spontaneous in 12, and iatrogenic in 25 defects (15 from endoscopic sinus surgeries and 10 from neurosurgical procedures). Fifty-two percent of defects presented with a meningoencephalocele. Defect location was sphenoid sinus (17 defects), ethmoid roof (14 defects), cribriform plate (9 defects), and frontal sinus (2 defects). Defect size ranged from 1x1 mm to 2x2 cm. Follow-up ranged from 8 to 46 months. All defects were identified preoperatively on HRCT with successful intraoperative IGS localization. No patients required IF for identification of CSF leak. Overall successful repair was achieved in 40 (95%) defects after initial repair, and 100% after revision. Seven patients had LD, 6 patients were early in the series. Twenty-three patients were discharged the day after surgery and 6 patients were discharged on day 2. Using preoperative HRCT for diagnosis and intraoperative IGS for localization, even small skull base defects can be definitively identified. High success rates and early discharges are achieved without additional procedures such as IF or LD. This is a less invasive and more cost-efficient method of repairing CSF leaks.

Long-Term Endonasal Endoscopic Review of Successful Duraplasty after Endonasal Endoscopic Skull Base Surgery

This study was performed to examine the long-term endonasal endoscopic morphological appearance of successful duraplasty after endoscopic skull base surgery for different pathology. This study included 65 patients who underwent endonasal endoscopic surgery for different skull base lesions with successful duraplasty. Forty patients had pituitary adenomas, 25 with macroadenomas and 15 with microadenomas. Twenty patients with cerebrospinal fluid rhinorrhea of different etiologies and three patients with meningoencephalocele were included. There were two patients with skull base meningiomas, 1 with an extensive greater wing meningioma reaching the nasal cavity and the 1 with recurrent olfactory groove meningioma. Different types of autologous materials were used in reconstructing the skull base defect. Clinical follow-up with endoscopic nasal examination was done routinely 1, 3, 6, and 12 months after surgery. CT and MRI were performed when indicated. The follow-up period ranged from 6 months to 8 years. Starting from 3 months after surgery to the rest of the follow-up period, endonasal endoscopic view of the site of duraplasty showed that with small skull base defect (<5 mm), there was neither dural pulsation nor prolapse. With moderate-size defect (5-10 mm) there was dural pulsation without prolapse. With larger defect (>10 mm) there was dural pulsation and prolapse. These findings were constant regardless of the etiology of the lesion and the reconstruction material used. This long-term study showed that dural pulsation and prolapse at the site of the successful duraplasty is a function of the size of the bony defect and does not depend on the pathology of the lesion or the autologous material used for reconstruction. For any future endonasal procedure for these patients, the surgeons should be fully aware of the state of duraplasty to avoid any complication.

An unusual presentation of renal cell carcinoma with late metastases to the small intestine, thyroid gland, nose and skull base

An unusual presentation of renal cell carcinoma with late metastases to the small intestine, thyroid gland, nose and skull base