Abstract: Object Cavernous sinus (CS) invasion is the most important preoperative predictor of remission in the surgical treatment of growth hormone–producing pituitary adenomas. The purpose of this study was to evaluate the effectiveness of an aggressive technique for removal of tumors invading the CS in patients with acromegaly. Methods The authors retrospectively reviewed the cases of 150 consecutive patients with acromegaly who underwent primary transsphenoidal surgery in 2010 and 2011. The authors reviewed preoperative Knosp grade, intraoperative findings, histology of the medial wall of the CS, and surgical outcome according to the current consensus criteria for acromegaly. Results Cavernous sinus invasion was identified in 55 patients (36.7%): definite CS involvement by the tumor was observed under direct vision in 41 patients (74.5%), while invasion was histologically verified in 39 patients (70.9%). Invasion increased in frequency with the higher Knosp grade but was observed in 14.4% (13 of 90) of Grade 0 ...

Abstract: Background Injuring the internal carotid artery (ICA) is a feared complication of endoscopic endonasal approaches. Objective To introduce a comprehensive ICA classification scheme pertinent to safe endoscopic endonasal cranial base surgery. Methods Anatomic dissections were performed in 33 cadaveric specimens (bilateral). Anatomic correlations were analyzed. Results Based on anatomic correlations, the ICA may be described as 6 distinct segments: (1) parapharyngeal (common carotid bifurcation to ICA foramen); (2) petrous (carotid canal to posterolateral aspect of foramen lacerum); (3) paraclival (posterolateral foramen lacerum to the superomedial aspect of the petrous apex); (4) parasellar (superomedial petrous apex to the proximal dural ring); (5) paraclinoid (from the proximal to the distal dural rings); and (6) intradural (distal ring to ICA bifurcation). Corresponding surgical landmarks included the Eustachian tube, the fossa of Rosenmuller, and levator veli palatini for the parapharyngeal segment; the vidian canal and V3 for the petrous segment; the fibrocartilage of foramen lacerum, foramen rotundum, maxillary strut, lingular process of the sphenoid bone, and paraclival protuberance for the paraclival segment; the sellar floor and petrous apex for the parasellar segment; and the medial and lateral opticocarotid and lateral tubercular recesses, as well as the distal osseous arch of the carotid sulcus for the paraclinoid segment. Conclusion The proposed endoscopic classification outlines key anatomic reference points independent of the vessel's geometry or the sinonasal pneumatization, thus serving as (1) a practical guide to navigate the ventral cranial base while avoiding injury to the ICA and (2) further foundation for a modular access system.

Abstract: BACKGROUND AND PURPOSE: Immunoglobulin G4–related disease is a systemic fibroinflammatory process of unknown etiology, characterized by tissue infiltration by immunoglobulin G4 plasma cells. The purpose of this study was to retrospectively identify the spectrum of imaging features seen in immunoglobulin G4–related disease of the orbit. MATERIALS AND METHODS: This study included 27 patients with biopsy-proved immunoglobulin G4–related disease of the orbit and either a CT or MR imaging of the orbits. These CT or MR imaging examinations were evaluated for the following: extraocular muscle size, extraocular muscle tendon enlargement, lacrimal gland enlargement, infiltrative process in the orbital fat (increased attenuation on CT or abnormal signal on MR imaging), infraorbital nerve enlargement, mucosal thickening in the paranasal sinuses, and extension of orbital findings intracranially. RESULTS: Extraocular muscles were enlarged in 24 of 27 (89%) patients, 21 (88%) bilaterally. In 32 of 45 (71%) affected orbits, the lateral rectus was the most enlarged muscle. In 26 (96%) patients, the tendons of the extraocular muscles were spared. Nineteen (70%) patients had lacrimal gland enlargement. Twelve (44%) patients had an infiltrative process within the orbital fat. Infraorbital nerve enlargement was seen in 8 (30%) patients. Twenty-four (89%) patients had sinus disease. Cavernous sinus or Meckel cave extension was seen in 3 (11%) patients. CONCLUSIONS: In patients with extraocular muscle enlargement, particularly when the tendons are spared and the lateral rectus is the most enlarged, and even more so when other noted findings are present, immunoglobulin G4–related disease should be a leading differential consideration, even over more commonly known etiologies of extraocular muscle enlargement. IgG4 : immunoglobulin G4

Abstract: OBJECTIVE Neurosarcoidosis is a rare granulomatous disease that can result in cranial neuropathy, chronic meningitis, and intracranial granuloma formation. Meningeal involvement may cause focal nodular enhancement that can simulate common cranial base tumors. The objective of the current study is to further define the clinical features of neurosarcoidosis in a large cohort of patients, focusing on characteristics relevant to the skull base surgeon. STUDY DESIGN Retrospective series. SETTING Two tertiary academic referral centers. PATIENTS Consecutive patients diagnosed with neurosarcoidosis. INTERVENTION(S) Review of clinical presentation, physical examination, radiologic findings, biopsy results, and laboratory testing. MAIN OUTCOME MEASURES Prevalence and distribution of cranial neuropathy, radiologic features of meningeal enhancement, and patterns of simulated tumors. RESULTS A total of 305 patients met study criteria. The mean age at diagnosis was 47 years and 53% were female. The optic nerve was the most commonly involved cranial nerve, followed by the trigeminal and the facial nerve. Meningeal enhancement was present in 67% of cases with 17% demonstrating focal or multicentric nodular enhancement simulating tumor. The most common locations of inflammatory tumor development included the cavernous sinus, petrous temporal bone, and sphenoid wing; six patients had bilateral internal auditory canal lesions, several mimicking neurofibromatosis type II. CONCLUSION Establishing the diagnosis of neurosarcoidosis remains challenging. Meningeal involvement and cranial neuropathy often mimic other more common conditions. Careful review of patient history and clinical imaging can reveal important clues toward the diagnosis of neurosarcoidosis. The clinician must maintain a high index of suspicion in patients with atypical presentation to avoid misdiagnosis and facilitate early medical treatment.

Abstract: BACKGROUND AND PURPOSE: Aneurysms of the cavernous segment of the ICA are difficult to treat with standard endovascular techniques, and ICA sacrifice achieves a high rate of occlusion but carries an elevated level of surgical complications and risk of de novo aneurysm formation. We report rates of occlusion and treatment-related data in 44 patients with cavernous sinus aneurysms treated with flow diversion. MATERIALS AND METHODS: Patients with cavernous segment aneurysms treated with flow diversion were selected from a prospectively maintained data base of patients from 2009 to the present. Demographic information, treatment indications, number/type of flow diverters placed, outcome, complications (technical or clinical), and clinical/imaging follow-up data were analyzed. RESULTS: We identified 44 patients (37 females, 7 males) who had a flow diverter placed for treatment of a cavernous ICA aneurysm (mean age, 57.2; mean aneurysm size, 20.9 mm). The mean number of devices placed per patient was 2.2. At final angiographic follow-up (mean, 10.9 months), 71% had complete occlusion, and of those with incomplete occlusion, 40% had minimal remnants ( CONCLUSIONS: Our series of flow-diversion treatments achieved markedly greater rates of complete occlusion than coiling, with a safety profile that compares favorably with that of carotid sacrifice.

Abstract: Object This paper describes a consecutive series of skull base meningiomas resected using an endoscopic endonasal approach through various corridors at a single institution over 7 years. The impact of case selection and experience, the presence of a cortical cuff between the tumor and surrounding vessels, and brain edema on morbidity and rates of gross-total resection (GTR) were examined. Methods A retrospective review of a series of 46 skull base meningiomas from a prospective database was conducted. The series of cases were divided by location: olfactory groove (n = 15), tuberculum and planum (n = 20), sellar/cavernous (n = 9) and petroclival (n = 2). Gross-total resection was never intended in the sellar/cavernous tumors, which generally invaded the cavernous sinus. Clinical charts, volumetric imaging, and pathology were reviewed to assess the extent of resection and complications. Cases were divided based on a time point in which surgical technique and case selection improved into Group 1 (surgery pri...

Abstract: Abducens nerve palsy is the most common complication after transvenous embolization (TVE) for cavernous sinus dural arteriovenous fistula. Abducens nerve palsy is reported to have a good prognosis after the symptoms have been alleviated. The purpose of this study was to identify cases of delayed abducens nerve palsy after successful TVE and discuss the physiological mechanisms responsible for this unusual complication. Between 1991 and 2012, TVE was performed for 73 patients. The patients were evaluated for clinical symptoms every 12 months during the follow-up period. Patients’ data and information about abducens nerve palsy were obtained from clinical records retrospectively. Abducens nerve palsy newly developed in 4 (5.5 %) of 73 patients at 3–65 months after TVE. All four patients with delayed abducens nerve palsy were followed up for 8–84 months. However, delayed abducens nerve palsy persisted in all four patients. In these four patients, the shunt points were posterior cavernous sinus. The average coil length used for four patients was 206.5 ± 43.1 cm (n = 4), and the average coil length used for patients without delayed abducens nerve palsy was 112.8 ± 38.8 cm (n = 69). The possibility of delayed abducens nerve palsy should be kept in mind, especially in the patients who were treated with transvenous coil packing in the posterior part of the cavernous sinus. Furthermore, our results suggest that long-term follow-up care is important for these patients, even after complete neurological and radiological recovery was attained.

Abstract: Although the value of early MR imaging has been justified for microscopic transphenoidal surgery, there is no literature evaluating immediate postoperative MR imaging following endoscopic endonasal resection of pituitary adenomas. We hypothesized that MRI of the pituitary gland performed on the first postoperative day is just as effective at detecting residual disease and/or reconstruction materials as the MRI at 3 months following surgery. We retrospectively evaluated 102 consecutive patients who underwent endoscopic endonasal surgery for presumed pituitary adenomas. Sixty-four patients met the inclusion criteria with immediate and 3 months MR imaging. Imaging was evaluated by two sets of observers. The following parameters were assessed: enhancement pattern of the pituitary gland, pituitary stalk, nodular enhancement (residual tumor) or linear enhancement (non-tumoral) and residual reconstruction/packing materials. Gross total resection of the tumors with no cavernous sinus involvement was achieved in 49 out of 52 (94 %) patients. Eleven out of 12 remaining patients with cavernous sinus invasion had residual cavernous sinus component visible on both immediate and 3 month MR imaging. The pituitary gland, position of stalk, and nasoseptal flap could be identified on both post-operative MRIs in all patients. The sensitivity and specificity for residual tumor detection on immediate MRI was 100 % and 97.9 %, respectively. The kappa index evaluating interobserver agreement for identification of residual tumor and packing/reconstruction material on immediate MR was 0.83 and 0.72 indicating near perfect and substantial agreement, respectively. Immediate MR imaging performed following endoscopic endonasal resection of pituitary lesions provides accurate and reliable information regarding the presence of residual tumor compared to reconstruction and packing materials.

Abstract: Pediatric skull base meningiomas are rare and complex clinical entities. Meningioma is a relatively uncommon brain tumor in children, and only ∼ 27% involve the skull base. Some evidence suggests that these tumors are more likely to be atypical or malignant in children than adults. The absence of female preponderance in pediatric meningiomas is reflected in the skull base subpopulation. Skull base meningiomas in children are most likely to be found in the anterior or middle fossa base, or involving the orbit and optic nerve sheath. Petroclival, suprasellar/parasellar, cerebellopontine angle, cavernous sinus, and foramen magnum tumors are very rare. Meningiomas constitute a small proportion of reported cases of pediatric skull base pathology, and they are entirely absent from many case series. Initial gross total resection is consistently associated with superior outcomes. Surgical approaches to the pediatric skull base must take additional factors into consideration including relatively smaller anatomy, immature dentition, incompletely aerated sinuses and air cells, and altered configurations of structures such as the pterional bony complex. Multidisciplinary expertise is essential to optimizing treatment outcomes.

Abstract: This educational paper reviews the normal anatomy of the cavernous sinus (CS) and the imaging findings of common and uncommon lesions of this region. CS lesions may arise from different components of the CS or from adjacent structures and spaces. They can be classified as tumoral, inflammatory/infectious, vascular and congenital. Tumoral lesions include benign (meningiomas, pituitary adenomas, schwannomas) and malignant neoplasms (chondrosarcomas, chordomas, nasopharyngeal carcinomas, leukemia, metastases). Inflammatory/infectious conditions comprise: Tolosa Hunt, abscess, Lemierre syndrome and thrombophlebitis. Vascular lesions include: hemangiomas, carotido-cavernous fistula, aneurysms, arteriovenous malformations. Congenital conditions include the epidermoid cyst, dermoid cyst and fatty deposits. Although imaging features of non-vascular CS diseases are most often non-specific, careful analysis of the adjacent structures suggests the correct diagnosis. In vascular pathology, characteristic MR imaging findings are observed.

Abstract: In recent years, resections of midline skull base tumors have been conducted using endoscopic endonasal skull base (EESB) approaches. Nevertheless, many surgeons reported that cerebrospinal fluid (CSF) leakage is still a major complication of these approaches. Here, we report the results of our 42 EESB surgeries and discuss the advantages and limits of this approach for resecting various types of tumors, and also report our technique to overcome CSF leakage. All 42 cases involved midline skull base tumors resected using the EESB technique. Dural incisions were closed using nasoseptal flaps and fascia patch inlay sutures. Total removal of the tumor was accomplished in seven pituitary adenomas (33.3%), five craniopharyngiomas (62.5%), five tuberculum sellae meningiomas (83.3%), three clival chordomas (100%), and one suprasellar ependymoma. Residual regions included the cavernous sinus, the outside of the intracranial part of the internal carotid artery, the lower lateral part of the posterior clivus, and the posterior pituitary stalk. Overall incidence of CSF leakage was 7.1%. Even though the versatility of the approach is limited, EESB surgery has many advantages compared to the transcranial approach for managing mid-line skull base lesions. To avoid CSF leakage, surgeons should have skills and techniques for complete closure, including use of the nasoseptal flap and fascia patch inlay techniques.

Abstract: Objective To investigate a novel dual-port endonasal and subtemporal endoscopic approach targeting midline lesions with lateral extension beyond the intracavernous carotid artery anteriorly and the Dorello canal posteriorly. Methods Ten dual-port approaches were performed on five cadaveric heads. All specimens underwent an endoscopic endonasal approach from the sella to middle clivus. The endonasal port was combined with an anterior or posterior endoscopic extradural subtemporal approach. The anterior subtemporal port was placed directly above the middle third of the zygomatic arch, and the posterior port was placed at its posterior root. The extradural space was explored using two-dimensional and three-dimensional endoscopes. Results The anterior subtemporal port complemented the endonasal port with direct access to the Meckel cave, lateral sphenoid sinus, superior orbital fissure, and lateral and posterosuperior compartments of the cavernous sinus; the posterior subtemporal port enhanced access to the petrous apex. Endoscopic dissection and instrument maneuverability were feasible and performed without difficulty in both the anterior and posterior subtemporal ports. Conclusion The anterior and posterior subtemporal ports enhanced exposure and control of the region lateral to the carotid artery and Dorello canal. Dual-port neuroendoscopy is still minimally invasive yet dramatically increases surgical maneuverability while enhancing visualization and control of anatomical structures.

Abstract: The transsphenoidal approach has been utilized in intrasellar craniopharyngioma surgeries. However, the advent of endoscopic extended transsphenoidal approach (EETSA) has expanded its indication to suprasellar craniopharyngiomas. We compared the indication and limitations of EETSA to those of unilateral basal interhemispheric approach (UBIHA), which presents similar indications for surgery. We analyzed 30 patients with tumors located below the foramen of Monro and the lateral boundary extending slightly beyond the internal carotid artery (UBIHA: N = 18; EETSA: N = 12). Postoperative magnetic resonance imaging (MRI) revealed gross total resection in 10 patients in the EETSA group (83.3%) and 12 in the UBIHA group (66.7%). Postoperative MRI in the EETSA group revealed residual tumor at the cavernous sinus in one patient, at the prepontine in one; in the UBIHA group, residual tumors were located in the retrochiasmatic area in two patients, infundibulum-hypothalamus in one, on the stalk in one, and in the intrasellar region in two. No intergroup differences were observed in the preservation of pituitary function and postoperative improvement of visual function. The extent of resection was better with EETSA than with UBIHA. EETSA is considered the first-line therapy because the distance between the optic chiasm and the superior border of the pituitary is large; the lateral extension does not go beyond the internal carotid artery; and the tumor does not extend inferiorly beyond the posterior clinoid process. However, in patients showing poorly developed sphenoid sinuses or pituitary stalks anterior to the tumor, surgery is difficult regardless of the selection criteria.

Abstract: Purpose: To study the clinical course with regard to both the angiographic and visual outcomes of carotid cavernous fistulas (CCFs).Background: Carotid cavernous sinus fistulas (CCFs) are conditions which often present with ocular signs and symptoms. The clinical presentation of CCFs is varied according to the anatomy, haemodynamics and size of the CCF. CCFs causing significant symptoms or vision loss should be treated with embolization.Methods: This is a retrospective review of the medical records of all CCF cases seen in the Singapore National Eye Centre from September 2002 to December 2011.Results: 45 patients who had confirmed CCF on conventional cerebral angiography were included. Anterior draining CCFs presented with orbital congestion while posterior draining CCFs presented with pain, diplopia and cranial nerve palsies. Mild residual symptoms were still present in 85% of treated direct CCFs despite complete angiographic closure however 52% of treated dural CCFs had complete resolution of sy...

Abstract: Although the inferior petro-occipital vein has been recently used for vascular access to the cavernous sinus, few detailed descriptions of its anatomy are in the literature. We aimed to investigate the morphology and relationships of this vessel. Twelve latex-injected cadaveric heads (24 sides) were dissected to identify the inferior petro-occipital vein and anatomic details documented. The petro-occipital vein was identified on 83.3% of sides. Generally this vein united the internal carotid venous plexus to the superior jugular bulb. However, on 10% of sides, the anterior part of this vein communicated directly with the cavernous sinus, and on 15%, the posterior vein drained into the inferior petrosal sinus at its termination into the superior jugular bulb. The petro-occipital vein was separated from the overlying inferior petrosal sinus by a thin plate of bone. On 40% of sides, small venous connections were found between these two venous structures. The vein was usually larger if a nondominant transverse sinus was present. The overlying inferior petrosal sinus was smaller in diameter when an underlying inferior petro-occipital vein was present. On 20% of sides, the posterior aspect of the vein communicated with the hypoglossal canal veins. On three sides, diploic veins from the clivus drained into the inferior petro-occipital vein. The inferior petro-occipital vein is present in most humans. This primarily extracranial vessel communicates with intracranial venous sinuses and should be considered an emissary vein. Knowledge of this vessel's exact anatomy may be useful to cranial base surgeons and endovascular specialists.

Abstract: BACKGROUND AND PURPOSE This study was designed to evaluate various magnetic resonance imaging (MRI) criteria for cavernous sinus (CS) invasion in preoperative evaluation of pituitary macroadenoma. METHODS The sellar MRIs of 63 patients (47 female, 16 male; age 17-67 years, mean of 42 years) who underwent surgery for pituitary macroadenoma were retrospectively reviewed. The following MR signs were assessed and compared with intraoperative findings, and statistical analyses were performed: (1) presence of hypointense-line suggestive of medial wall of CS on high-resolution coronal T2-weighted image, (2) presence of entire rim-enhancement around the intracavernous internal carotid artery (ICA) (“periarterial enhancement”), (3) location of the tumor in relation to the lateral intercarotid lines, and (4) angle of tumor encasement around the intracavernous ICA. RESULTS CS invasion was highly probable if periarterial enhancement was not depicted (positive predictive value, 86%; P < .001). Valuable criteria of CS invasion by logistic regression analysis were the absence of periarterial enhancement (P = .043, odds ratio = 5.23) and the angle of intracavernous ICA encased by the tumor (P = .029, odds ratio = 1.017) with a threshold value of 136.5° with a sensitivity of 90% and specificity of 78.3%. CONCLUSIONS MRI criteria may be helpful in evaluating the presence of CS invasion in pituitary macroadenoma.

Abstract: Ocular symptoms are regularly observed in patients with cavernous sinus dural arteriovenous fistulas (cDAVF). We aimed to evaluate the long-term efficacy and safety of endovascular approaches in patients with cDAVF presenting with different ocular symptoms. In a prospective study between June 2008 and March 2013, 46 patients with ocular symptoms due to cDAVF who were not eligible for conservative therapy, met the inclusion criteria and underwent endovascular treatment. They underwent a transarterial approach with histoacryl glue injections or transvenous coil embolization, all in one session. They were followed up for a mean period of 17.3 months (range 7 to 30 months) clinically and using angiography. The mean age of patients was 36.8 years (18-60) and 65% of them were male. All patients showed venous drainage into the superior and inferior orbital veins. Access to the cavernous sinus was transvenous in ten patients, transarterial in 26 patients, and mixed in ten patients. Initial symptoms were improved in 97.8% of patients and did not recur during the study follow-up. The procedural complications included: blurred vision, transient sixth nerve palsy and exacerbation of chemoproptosis in two, one and two patients respectively that completely resolved in initial weeks with no recurrence. No patient worsened or developed new symptoms suggestive of a recurrent fistula during the follow-up period. One patient experienced intracranial dissection of the internal carotid artery and ischemic stroke with an unfinished procedure. The relief of early presentation was durable in long-term follow-up and the cured lesions were stable in angiographic controls. Favorable and durable outcomes could be obtained following endovascular approaches for cDAVF presenting with different ocular symptoms.

Abstract: Approximately 5,000 trans-sphenoidal surgeries are performed for resection of pituitary tumors each year in the United States. The rise in popularity of the trans-spehnoidal approach, though described nearly a century ago, has been facilitated over the last decades by advances in technique and technology. In this review, we discuss the relative strengths of microscopic and endoscopic techniques for pituitary tumor resection. However, despite being the standard of care for patients with most pituitary tumors, cure rates for many subtypes of pituitary lesions, such as secretory macroadenomas or tumors with significant cavernous sinus invasion, remain unsatisfactory. We also describe two more recent advances in neurosurgical technique which may offer promise of increased rates of surgical cure: pseudocapsular resection and cavernous sinus approaches.

Abstract: BACKGROUND When feasible, the management of iatrogenic internal carotid artery (ICA) injury during skull base surgery is mainly endovascular. OBJECTIVE To propose a cerebral revascularization procedure as a rescue option when endovascular treatment is not feasible. METHODS We retrospectively reviewed all extracranial-intracranial (EC-IC) bypass procedures performed between July 2007 and January 2014. RESULTS From 235 procedures, we identified 8 consecutive patients with iatrogenic ICA injury managed with an EC-IC bypass. Injury to the ICA occurred during an endoscopic transsphenoidal surgery (n=3), endoscopic transfacial-transmaxillary surgery (n=1), myringotomy (n=1), cavernous sinus meningioma resection (n=1), posterior communicating artery aneurysm clipping (n=1), and cavernous ICA aneurysm coiling (n=1). Endovascular management was considered first-line treatment but was not successful. All patients received a high-flow EC-IC bypass. At a mean clinical/radiographic follow-up of 19 months (range, 3-36 months), all patients had a modified Rankin Scale score of 0 or 1. All bypasses remained patent. CONCLUSION Iatrogenic injury of the skull base ICA is uncommon but can lead to lethal consequences. Many injuries can be treated with endovascular techniques. However, certain cases may still require a cerebral revascularization procedure.

Abstract: Three cases of intracranial angioleiomyoma (ALM) in our neurosurgery center are reported in detail. ALM is a benign soft tissue tumor comprised of mature smooth muscle cells and a prominent vascular component, which is extremely rare as a primary intracranial lesion. Altogether, only 12 cases were recorded in the literature to date, to the best of our knowledge. Case 1 is the second report of intra-sella ALM, a 51-year-old woman presented with visual deterioration for 2 months. An MRI showed an intra-sella 3-cm tumor, partially flame-like, enhanced with gadolinium. Using microscopic endonasal transsphenoidal approach, the tumor was completely resected with great difficulty. At 11 days post-surgery, she died of a sudden catastrophic nasal hemorrhage. An angiography revealed a pseudo-aneurysm of ICA (internal carotid artery). Case 2 is a 49-year-old man who presented with weakness of the lower limbs for 1 year. A large subtentorial mass was found affixed to the torcular and straight sinus, which was partially flame-like, dramatically enhanced as in case 1. Case 3 is that of a 77-year-old man. An ALM mass was revealed in the diploe of left temporal bone, and had eroded the inner table. Immunohistochemical workup confirmed the diagnosis of angioleiomyoma in all 3 cases. The radiology, operation, and complication of surgery in each case were discussed. In conclusion, intracranial ALMs are extremely rare, usually located ex-neuro axis (such as in our cases), in the sella, in posterior fossa, or in the skull. Magnetic resonance imaging (MRI) revealed a special feature of flame-like partial enhancement that may be helpful to distinguish ALM from pituitary tumors or meningiomas, and should result in the consideration of this rare tumor entity early on in the diagnostic process. A definitive diagnosis depends on histological analyses. The resection of ALM in certain locations is difficult and risky because of the rich blood supply.

Abstract: Apart from the radiologic features regarding size and invasiveness, we had noticed some differences in morphology among types of pituitary adenomas. We conducted this study to verify the differences in radiologic morphology between growth hormone producing pituitary adenomas (GHoma) and nonfunctioning pituitary adenomas (NFoma). Pre-surgical magnetic resonance images (MRIs) were assessed in 50 cases of GHoma and 50 cases of NFoma. Geometric parameters on MRI were set in accordance with sellar anatomy. Intensity of T1-weighted image was not different between the two groups, but hypo-intensity of T2-weighted image was more frequently seen in GHoma. Predominant inferior extension of tumor was seen mostly in GHoma (88 vs. 38%). Extension of the tumor to the superior compartment of cavernous sinus was more frequent in NFoma. Pituitary gland was generally located superior to GHoma and postero-superior to NFoma. Growth characteristics of pituitary adenoma were confirmed to differ between GHoma and NFoma.

Abstract: Although the infratentorial superior-lateral cerebellar approach has been traditionally chosen for exposure of the V cranial nerve root in the process of microvascular decompression for treatment of trigeminal neuralgia, those petrosal veins often block this surgical corridor. To detour these petrosal veins, we require a new approach. We provide a via-cerebellar-fissures approach to expose well the trigeminal nerve. With microscopy, cerebrospinal fluid was drained sufficiently to relax the cerebellum. Caudally to petrosal veins, the dissection was started from the cerebellar fissures. With the arachnoid membranes around the petrosal fissure and superior cerebellopontine fissures being opened thoroughly, the root entry zone of V nerve was visualized directly. This new approach was used in 106 patients. Among them, the block veins were encountered in 17 (16.0%). Among the 17 vein-blocked cases, 1 or 2 branches of the veins were finally cut in 2 (1.9%). The postoperative relief rate was 95.3% without complications. This via-cerebellar-fissures approach may access the root entry zone of the V cranial nerve without killing those petrosal veins, which is worth to be recommended and popularized.

Abstract: Objective The identification of cranial nerves is one of the most challenging goals in the dissection of skull base meningiomas. The authors present an application of sodium fluorescein (SF) in skull base meningiomas with the purpose of improving the identification of cranial nerves. Design A prospective study within-subjects design. Setting Hospital Ernesto Dornelles, Porto Alegre, Brazil. Participants Patients with skull base meningiomas. Main Outcomes Measures Cranial nerve identification. Results The group of nine meningiomas was composed of one cavernous sinus, three petroclival, one tuberculum sellae, two sphenoid wing, one olfactory groove, and one temporal floor meningioma. The SF enhancement in all tumors was strong, and the contrast with cranial nerves clearly evident. There were one definite olfactory nerve deficit, one transient abducens deficit, and one definite hemiparesis. All lesions were resected (Simpson grades 1 and 2). The analysis of the difference of the delta SF wavelength between the meningiomas and cranial nerve contrast was performed by the Wilcoxon signed rank test and showed p = 0.011. Conclusions The contrast between the enhanced meningiomas and cranial nerves was evident and assisted in the visualization and microsurgical dissection of these structures. The anatomical preservation of these structures was improved using the contrast.