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Endovascular treatment for isolated dural arteriovenous fistula (DAVF) in the middle cranial fossa (MCF) with pure cortical venous drainage poses challenges, including the absence of a safe access route for transvenous embolization (TVE) and the risk of ischemia to neuro feeding vessels and dangerous anastomosis at the sphenoid wing. Therefore, surgical treatment involving direct blockage of venous reflux via craniotomy is typically preferred. We describe the case of a 63-year-old woman presented with generalized seizures and was diagnosed with a Borden III left MCF-DAVF. Initial TVE was unsuccessful due to an occluded inferior petrosal sinus and a lack of connection between the cavernous sinus and the shunt point. After reducing the shunt flow with transarterial embolization, retrograde TVE through cortical drainage enabled successful treatment for the DAVF. We used a triple coaxial system (4-French guiding sheath, 3.2-French intermediate distal access catheter, and 1.5-French microcatheter) to retrogradely navigate a microcathter from the right jugular vein through the superior sagittal sinus, the vein of Trolard, and into the superficial middle cerebral vein, ultimately achieving shunt occlusion using several coils. This case demonstrates that TVE for MCF-DAVFs with pure cortical venous drainage is feasible when a safe anatomical route is established using appropriate strategies and instruments and provides a safe and effective treatment option for similar cases.

Endovascular treatment for isolated dural arteriovenous fistula (DAVF) in the middle cranial fossa (MCF) with pure cortical venous drainage poses challenges, including the absence of a safe access route for transvenous embolization (TVE) and the risk of ischemia to neuro feeding vessels and dangerous anastomosis at the sphenoid wing. Therefore, surgical treatment involving direct blockage of venous reflux via craniotomy is typically preferred. We describe the case of a 63-year-old woman presented with generalized seizures and was diagnosed with a Borden III left MCF-DAVF. Initial TVE was unsuccessful due to an occluded inferior petrosal sinus and a lack of connection between the cavernous sinus and the shunt point. After reducing the shunt flow with transarterial embolization, retrograde TVE through cortical drainage enabled successful treatment for the DAVF. We used a triple coaxial system (4-French guiding sheath, 3.2-French intermediate distal access catheter, and 1.5-French microcatheter) to retrogradely navigate a microcathter from the right jugular vein through the superior sagittal sinus, the vein of Trolard, and into the superficial middle cerebral vein, ultimately achieving shunt occlusion using several coils. This case demonstrates that TVE for MCF-DAVFs with pure cortical venous drainage is feasible when a safe anatomical route is established using appropriate strategies and instruments and provides a safe and effective treatment option for similar cases., (© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.)

Solitary fibrous tumors (SFTs) exceptionally occur at the middle cranial fossa. A midline search from January 1997 up to June 2021 selected 16 articles for a total of 19 patients, where the tumor attachment was completely or largely (>75%) at the middle cranial fossa. The unique personal case concerns a 35 years old woman complaining of left hypoacusia and moderate left facial paresis. A high grade SFT of the left middle fossa was resected, with no recurrence 8 years after surgery and irradiation. The 20 patients of the review, including ours, are 11 men and 9 women with a median age of 47 years. The location was mainly intradural (47%) or extra-intradural (42%); the invasion of the petrous bone was evidenced in a half of the patients. Symptoms of involvement of the Vth, VIIth and VIIIth cranial nerve were more frequent (3/4 of the cases). Variable T2 signal, lobulated margins and inhomogeneous enhancement were the most frequent MRI features. Histologically most tumors (70%) were WHO grade III and 23% grade I. A gross total resection was possible in 55% of the cases. The recurrence rate is significant (23,5%). Older patient age (>50 years), large tumor size, incomplete resection and high WHO grade histology are significant prognostic factors for recurrence. However, the outcome is sometimes unpredictable. Thus, a follow-up by serial MRI studies is strongly advisable.

Background: Amyloidoma is a rare mass lesion formed by abnormal deposition of amyloid proteins. There are 25 reported cases of Meckel's cave amyloidoma primarily involving the trigeminal nerve alone. Case presentation: A 55-year-old woman presented with one year of right-sided trigeminal neuropathy and facial weakness. On examination, there was right-sided V1-V3 dysesthesia and partial right facial paralysis. Magnetic resonance imaging (MRI) showed a right-sided enhancing 1.5 cm × 0.7 cm × 0.4 cm mass in Meckel’s cave. The mastoid segment of the right facial nerve demonstrated focal enhancement. A biopsy of the Meckel’s cave lesion was performed via a right lateral transorbital approach. Results: Histologic sections showed pale eosinophilic amorphous material birefringent to polarized light in Congo red stain. Mass spectrometry confirmed a lambda light chain amyloidoma. Extensive workup did not reveal evidence of systemic amyloidosis, consistent with localized central nervous system (CNS) amyloidoma in Meckel’s cave. The patient remains stable at nine months. Conclusion: This is a rare case of primary Meckel’s cave amyloidoma affecting cranial nerves V and VII. A minimally invasive lateral transorbital approach was employed to access the tumor in the middle cranial fossa. Amyloidoma should be considered in the differential diagnosis of lesions involving Meckel’s cave and multiple cranial nerves.

We describe a 58-year-old man with a unique complication of chronic mandibular osteomyelitis. He presented with a unilateral facial nerve palsy and a non-traumatic dislocation of the mandibular condyle into the middle cranial fossa combined with a temporal lobe abscess. An odontogenic infection had already been festering for 18 months. After stereotactic puncture, P. Aeruginosa was cultured out of the brain abscess and the patient was treated with a culture-based antibiotic therapy followed by condylectomy and myofascial temporalis flap. One year after the surgery, the patient had a partial ossification of the glenoid fossa, recovered mouth opening and sufficient function. This report shows that the rare complication of chronic mandibular osteomyelitis with concurrent brain abscess can be treated successfully using a combination of aggressive long-term culture-based antibiotic treatment and a multidisciplinary surgical approach.

Skull-based neuroendocrine carcinomas are rare tumors with only a few case reports in literature. Here we present an unusual case of primary neuroendocrine carcinoma of the skull in 60-year-old male which was proven on surgical biopsy. The imaging features of this rare tumor along with differential diagnosis are discussed with brief review of the literature.

Background: The foramen spinosum (FS) transmits the middle meningeal vessels and meningeal branches of the mandibular nerve. The anatomical variation of FS is of great clinical significance in tumor detection and abnormal bony growth. This study aimed to assess morphometric measurements of the foramen spinosum and its variation in shape, number, and position to the sphenoid spine. Methods and materials: An anatomical study was conducted on 64 adult skulls. The study material involved human macerated Ethiopian skulls. Using a screw-adjusted compass and Vernier calipers, all measurements were taken. The area of the foramen spinosum was determined using formula A= (π x L x B)/4[π = 3.14, L = length, B = width]. The mean (±SD) was calculated for all the measurements. SPSS version 20 software was used to analyze the data, and P

Introduction: The aim of present study was to undertake detailed analysis of variations in morphology of orbito-meningeal foramen (OMF), a clinically relevant entity due to possible association with major arterial branches. Materials & methods: The study was conducted on 70 bony orbits of 35 dry adult human skulls. Precise identification of OMF's were ensured and other known bony canals in the orbit were excluded. All observations and measurements were undertaken by two observers independently to reduce chances of error. Results: Overall incidence of OMF was 71.24% (left side 76% and right side 68%) and were present as single entity in orbit in most cases (80.56%) with multiplicity noted. The OMF's in present study were classified according to three parameters: size of lumen (large/medium/small), termination of canal in cranial fossa (M-Type/A -Type/ND Type) and bony component of orbit where it was located (frontal/sphenoid/fronto-sphenoid suture). Variations were noted regarding the morphology of OMF across all the three parameters in comparison to published literature. Most of the large OMF (80%) were of M-Type (opened in the middle cranial fossa). M-Type of OMF were single entities in 78.26% cases and were distributed proportionately across all three bony components of orbit. Conclusion: Based on analysis of findings it is suggested that presence of solitary OMF with large (>0.3 mm) lumen in any of the three bony components of orbit is mostly M-Type and has a high possibility of a major arterial branch passing through it. Findings could be useful towards pre-operative workup before orbital surgeries. Knowledge regarding the variations in morphological details of OMF may reduce the risk of inadvertent vascular injury in orbital region.

Background: The arcuate eminence (AE) is an anatomically consistent bony protrusion located on the upper surface of the petrous bone that has been previously studied as a reference for lateral skull base approaches. There is a paucity of information in the neurosurgical literature seeking to improve the safety of the extended middle cranial fossa (MCF) approach using detailed morphometric analysis of the AE., Objective: To evaluate the use of the AE as an anatomical landmark to help with early identification of the internal acoustic canal (IAC) in MCF approaches by means of a cadaveric study, using a new morphometric reference termed the "M-point.", Methods: A total of 40 dry temporal bones and 2 formalin-preserved, latex-injected cadaveric heads were used. The M-point was established as a new anatomic reference by identifying the intersection of a line perpendicular to the alignment of the petrous ridge (PR), originating from the midpoint of the AE, with the PR itself. Subsequent anatomical measurements were performed to measure the distance between M-point and IAC. Additional distances, including PR length and the anteroposterior and lateral AE surfaces, were also measured., Results: The mean distance between the M-point and the center of the IAC was 14.9 mm (SD ± 2.09), offering a safe drilling area during an MCF approach., Conclusions: This study provides novel information on identification of a new anatomic reference point known as the M-point that that can be used to improve early surgical identification of the IAC., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Transcranial surgery is considered more appropriate than an endonasal endoscopic approach (EEA) for a large cavernous sinus meningioma with lateral extension. Case presentation: A 6-cm-diameter hypervascular meningioma around cavernous sinus invaded the orbital apex and infratemporal fossa. 80% of the tumor was removed without too much blood loss via endoscopic endonasal transpterygoidal-infratemporal approach. Preoperative embolization from some feeding arteries was done, and 80% of the tumor staining disappeared. Discussion: Tumor removal rates for giant meningioma are worse with EEA than with the transcranial approach because of various anatomical limitations and blood control. Recently, EEA has become more widely used with approaches such as the transpterygoidal approach. The operation can be done safely with preoperative embolization because the operative view is clear without bleeding. Conclusion: Preoperative embolization for a large hypervascular tumor makes EEA more effective. A giant meningioma can be removed by EEA if the anatomical limitations can be identified and approached safely and effectively.

Background: Adequate epidural procedures and anatomical knowledge are essential for the technical success of skull base surgery. We evaluated the usefulness of our three-dimensional (3D) model of the anterior and middle cranial fossa as a learning tool in improving knowledge of anatomy and surgical approaches, including skull base drilling and dura matter peeling techniques., Methods: Using a 3D printer, a bone model of the anterior and middle cranial fossa was created based on multi-detector row computed tomography data, incorporating artificial cranial nerves, blood vessels, and dura mater. The artificial dura mater was painted using different colors, with 2 pieces glued together to allow for the simulation of peeling the temporal dura propria from the lateral wall of the cavernous sinus. Two experts in skull base surgery and 1 trainee surgeon operated on this model and 12 expert skull base surgeons watched the operation video to evaluate this model subtlety on a scale of 1 to 5., Results: A total of 15 neurosurgeons, 14 of whom were skull base surgery expert, evaluated, scoring 4 or higher on most of the items. The experience of dural dissection and 3D positioning of important structures, including cranial nerves and blood vessels, was similar to that in actual surgery., Conclusions: This model was designed to facilitate teaching anatomical knowledge and essential epidural procedure-related skills. It was shown to be useful for teaching essential elements of skull-base surgery., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Superior semicircular canal dehiscence (SSCD) is an abnormality of the otic capsule, which normally overlies the superior semicircular canal. Surgical management is indicated in patients with persistent and debilitating symptoms. Given the complexity of the disease, there are patients who experience less favorable surgical outcomes and require revision surgery. The purpose of this study was to report to the rate of postoperative symptomatic improvement in patients who required revision surgery., Methods: A retrospective analysis of patients undergoing SSCD surgical repair at a single institution was performed. Information on patient demographics, primary and secondary surgical approaches, surgical outcomes, and follow-up length was collected., Results: Seventeen patients underwent 20 revision surgeries. There were eleven (65%) females and six (35%) males. Mean age of the cohorts was 50 years (range 30-68 years), and mean follow-up length was 6.8 months (range 0.1-31.1 months). Cerebrospinal fluid leak was noted in 67% of cases. The greatest postoperative symptomatic resolution was reported in oscillopsia (100%), headache (100%), and internal sound amplification (71%), while the least postoperative symptomatic resolution was reported in tinnitus (42%), aural fullness (40%), and dizziness (29%)., Conclusions: Revision surgery can provide symptomatic improvement in select SSCD patients; however, patients should be cautioned about the possibility of less favorable outcomes than in index surgery. Revision surgeries are associated with a considerably higher rate of perioperative cerebrospinal fluid leak., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Among the new perspectives to revolutionize skull base surgery, there are the transorbital neuroendoscopic (TONES) approaches to reach the anterior and middle cranial fossa (ACF and MCF). We conceived to explore the potentialities of a modified superiorly and medially extended lateral retrocanthal (LRC) approach., Methods: Six head specimens were dissected. Applying the established conic model and the key surgical landmark of sphenofrontal suture, we tested the feasibility of a modified LRC to reach ACF and MCF; computed tomography (CT) scans were performed before and after dissection to obtain a morphometric analysis of the surgical corridors using a polygonal surfaces model., Results: Through our anatomical study, we were able to identify and explore 3 different surgical corridors to reach the ACF and MCF: the superomedial, the superolateral, and the inferolateral. The superomedial corridor appeared most suitable to reach the medial part of the ACF and the optic-carotid region, whereas through the superolateral and inferolateral corridors it was possible to reach and explore the lateral part of ACF and MCF. The mean volumes of the 3 surgical corridors calculated on post-dissection CT scans were: 12.72 ± 1.99, 5.69 ± 0.34, and 6.24 ± 0.47 cm 3 , respectively., Conclusions: The development of TONES approaches has not replaced the traditional open or endoscopic approach; nonetheless, identification of surgical corridors and the possibility to combine them represent a major breakthrough. Clinical studies are necessary to demonstrate their validity and test the effectiveness, safety, and reproducibility of TONES approaches in managing lesions harboring in the ACF and MCF., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: The aim of this study was to define the structural relationship between the arcuate eminence (AE) and a known fixed external bony landmark, the root of the zygoma (ZR), and to determine its reliability as a consistent guide for guiding surgical approaches. To our knowledge, this is the only anatomic study to quantify the relationship between the AE and ZR., Methods: Twenty-one dry temporal bones were measured using digital calipers. The distance from the posterior aspect of the ZR to the midpoint of the AE was measured. Additionally, the anteroposterior distance between the ZR and AE and vertical distance between the 2 structures were measured. Student's t-test was used to compare the left and right sides., Results: An AE was found in every specimen. The mean ZR to AE distance was 30.9 mm. On most sides (91%), the ZR was located more inferiorly than the AE with a mean distance of 3 mm between the 2 structures. The mean distance between the AE and ZR was 17 mm. On all sides, the AE was located posterior to the ZR. No significant differences were found between sides. No anatomic variations or pathologic conditions were noted in any of the specimens., Conclusions: The ZR is an easily identifiable and consistent bony landmark often used by skull base surgeons. In this investigation, we measured the anatomic relationships between the ZR and AE. Such data might assist in planning surgical trajectories and minimizing complications when skull base pathologies are approached., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: The pattern of recurrence of large trigeminal neurinomas is analyzed on the basis of experience with 7 cases., Methods: This is a report of 7 cases of large trigeminal neurinomas that were operated on an average of 11 years earlier. After being relatively asymptomatic over the years, these patients worsened relatively suddenly in their neurologic symptoms and were reoperated., Results: Imaging showed massive recurrence with tumor having cystic and solid components with sizes ranging from 4.5-11 cm. In 4 cases, the cysts at the time of initial presentation and at the time of recurrence showed a well-defined fluid level within the fluid content of the cyst. During operation it was seen that the tumor contained "hemorrhagic" fluid that was under significant pressure. The solid component in the circumferential periphery of the cyst fluid was soft, necrotic, and vascular. The entire recurrence in the middle and posterior cranial fossa and in the extracranial compartment was "interdural" or within the dural confines. Radical tumor resection within the dural confines by deploying relatively small surgical exposure resulted in "unusually" rapid recovery in the symptoms. Histological examination of the tumor did not reveal any malignant transformation., Conclusions: The cases add further insight to the growth pattern and characteristics of large trigeminal neurinomas., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To quantitatively compare different microsurgical and endoscopic approaches to the middle cranial fossa in a preclinical setting with a novel, computer-based research method., Methods: Different approaches were performed bilaterally in 5 head and neck specimens that underwent high-resolution computed tomography scans: 5 transcranial anterolateral (supraorbital, mini-pterional, pterional, pterional-transzygomatic, fronto-temporal-orbito-zygomatic) without and with anterior clinoidectomy; 2 transcranial lateral (subtemporal and subtemporal-transzygomatic); 2 endoscopic transnasal (transpterygoid, transpterygoid to infratemporal fossa); 2 endoscopic transorbital (superior eyelid and inferolateral), and endoscopic transmaxillary. A dedicated navigation system was used to quantify surgical working volumes and exposure of different areas of the middle cranial fossa (ApproachViewer, part of GTx-Eyes II, University Health Network, Toronto, Canada). Statistical analysis was performed using a mixed linear model with bootstrap resampling., Results: Endoscopic transnasal and fronto-temporal-orbito-zygomatic approaches with anterior clinoidectomy showed the largest surgical volumes. Endoscopic approaches allowed a wider exposure of medial anatomical surfaces (e.g., the petrous apex) compared with transcranial ones. Transcranial approaches with larger craniotomies allowed the widest exposure of superomedial anatomical structures (e.g., roof of cavernous sinus). The resection of the zygomatic arch allowed exposure of more medial surfaces with an inferior to superior trajectory., Conclusions: This study implemented a novel neuronavigation-based research method to quantitatively compare different approaches to the middle cranial fossa; its results might guide, after consideration of clinical implications, the choice of the neurosurgical approach to different areas of this complex skull base region., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Dislocation of the mandibular condyle into the middle cranial fossa is a rare injury that can be seen after facial trauma. Early identification of condyle dislocation into the middle cranial fossa was difficult until the development of computed tomography, and diagnosis was often significantly delayed after the initial trauma., Case Description: We present a rare case of a young woman who presents after a mechanical fall resulting in facial trauma with an avulsion condyle fracture with dislocation of the mandibular condyle into the middle cranial fossa., Conclusions: To our knowledge, this complete avulsion of the condyle into the middle cranial fossa requiring an intracranial approach for condylectomy is extremely rare. We discuss the surgical management options for reduction and fixation accomplished in a multidisciplinary approach involving neurosurgery and oral maxillofacial surgery., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: The Meckel's cave (MC) is commonly affected by neoplastic lesions that often require neurosurgical treatment. We simulated the posterior petrous apicectomy (PPA) on fresh cadavers to verify the in vivo feasibility of the approach. We proposed a new classification system of MC meningioma based on the extent of middle cranial fossa (MCF) involvement., Methods: Ten fresh, non-formalin-fixed specimens were used in this study. Through a retrosigmoid approach, 20 PPAs were performed. Subsequently, the cerebral hemispheres were removed to quantify the MCF exposure and dimensions of the suprameatal tubercle. Twenty-four patients operated on for MC meningioma were classified as follows: group 1, tumor <3 cm; group 2, tumor >3 cm. Group 2 was subdivided into to 5 subtypes: 2A, tumor of the MCF; 2B, tumor of the posterior cranial fossa; 2C, tumor of MCF and posterior cranial fossa; 2C type I, MCF <15 mm; and 2C type II, MCF >15 mm., Results: The extent of MCF exposure through the PPA is 13 mm. Mean suprameatal tubercle dimensions were 10.4 mm × 3.8 mm. Mean extent of bony removal for the PPA was 10.2 mm. PPA was successfully performed in 3 patients without major neurologic sequelae., Conclusions: Preliminary results obtained with the PPA in 2C type I meningiomas are encouraging. The new classification system proposed can be useful in clinical practice, especially in the choice of the most suitable surgical approach for dumbbell meningiomas., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Dural arteriovenous fistulas (AVFs) in the middle cranial fossa are rare. Pial AVFs are similarly rare but differ from dural AVFs in that they derive their arterial supply from pial or cortical arterial vessels and do not lie within the intradural region. We report an extremely rare case of dural and pial AVF connected to the same drainer in the middle cranial fossa., Case Description: In a 58-year-old man with a subcortical hemorrhage in the right temporal lobe, digital subtraction angiography showed a dural AVF in the middle cranial fossa fed by the middle meningeal artery (MMA) and draining into the sphenopetrosal vein. A combination with a small pial AVF connected to the same sphenopetrosal vein was suspected. Open surgery was performed to directly observe the shunt points. Transarterial indocyanine green (ICG) angiography using the MMA via the superficial temporal artery on a skin flap was performed to repeatedly and distinctly evaluate the dural shunt points and to prevent cerebral thromboembolism. Although the dural supply was completely disconnected, the sphenopetrosal vein remained arterialized. ICG angiography revealed pial AVF, which was fed by the cortical arteries draining into the same drainer. The pial supply was completely disconnected, and disappearance of the dural and pial AVF was confirmed., Conclusions: We report an extremely rare case of dural and pial AVF connected to the same drainer in the middle cranial fossa. To our knowledge, this is the first such case report described in the literature., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: In recent years, transorbital endoscopic approaches are increasing in popularity as they provide several corridors to reach lateral areas of the ventral skull base through the orbit. The aim of this study is to investigate the feasibility of the inferolateral transorbital endoscopic approach (ILTEA) by detailing the step-by-step dissection, anatomic landmarks, and target anatomic areas., Methods: Seven cadaveric specimens (14 sides) were dissected in the Laboratory of Endoscopic Anatomy of the University of Brescia. Step-by-step dissection of ILTEA was performed to identify the main anatomic landmarks and corridors. Skin incision, dural incision, and boundaries of craniectomy were measured. Neuronavigation was used to check landmarks, track boundaries of surgical volumes, and measure orbital dislocation., Results: The study on the 14 ILTEAs defined 1 anatomic area ("waterline door") that leads to 4 corridors: Meckel's cave corridor, carotid foramen corridor, petrous corridor, and transdural middle fossa corridor. Crucial anatomic landmarks were identified and analyzed. Orbital dislocation was <10 mm., Conclusions: ILTEA provides the surgeon with a direct route to the region of the "waterline door," lateral areas of the ventral skull base, and middle cranial fossa. In addition, it allows an optimal view of the intracranial and extracranial portions of the maxillary and mandibular nerves. Further anatomic and clinical studies are needed to validate ILTEA in surgical practice., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objective: Temporal bone encephalocele has become less common as the incidence of chronic mastoid infection and surgery for this condition has decreased. As a result, the diagnosis is often delayed, and the encephalocele is often an incidental finding. This situation can result in serious neurologic complications with patients presenting with cerebrospinal fluid leak and meningitis. We review the occurrence of, characteristics of, and repair experience with temporal encephaloceles from 2000-2012., Methods: We conducted a retrospective review of 32 patients undergoing combined mastoidectomy and middle cranial fossa craniotomy for the treatment of temporal encephalocele., Results: The diagnosis of temporal encephalocele was made in all patients using high-resolution temporal bone computed tomography and magnetic resonance imaging. At the time of diagnosis, 12 patients had confirmed cerebrospinal fluid leak; other common presenting symptoms included hearing loss and ear fullness. Tegmen defect was most commonly due to chronic otitis media (n = 14). Of these patients, 8 had undergone prior mastoidectomy, suggesting an iatrogenic cause. Other etiologies included radiation exposure, congenital defects, and spontaneous defects. Additionally, 2 patients presented with meningitis; 1 patient had serious neurologic deficits resulting from venous infarction., Conclusions: The risk of severe neurologic complications after the herniation of intracranial contents through a tegmen defect necessitates prompt recognition and appropriate management. Computed tomography and magnetic resonance imaging aid in definitive diagnosis. A combined mastoid/middle fossa approach allows for sustainable repair with adequate exposure of defects and support of intracranial contents., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objective: To describe the technical and anatomic nuances related to endoscopic endonasal approaches (EEAs) to the paramedian skull base., Methods: Surgical indications, limitations, and technical aspects pertaining to EEAs designed to access areas oriented in the coronal plane are systematically reviewed with special attention to caveats, pitfalls, and common complications and how to avoid them. Case examples are presented., Results: The paramedian skull base may be divided into anterior (corresponding to the orbit and its contents), middle (corresponding to the middle cranial, pterygopalatine, and infratemporal fossae), and posterior (includes the craniovertebral junction lateral to the occipital condyles and the jugular foramen) segments. EEAs to the anterior segment offer access to the intraconal orbital space and the optic canal. A transpterygoid corridor typically precedes EEAs to the middle and posterior paramedian approaches. EEAs to the middle segment provide wide exposure of the petrous apex, middle cranial fossa (including cavernous sinus and Meckel cave), and infratemporal and pterygopalatine fossae. Finally, EEAs to the posterior segment access the hypoglossal canal, occipital condyle, and jugular foramen., Conclusions: Approaches to the paramedian skull base are the most challenging and complex of all endoscopic endonasal techniques. Because of their technical complexity, it is recommended that surgeons master endoscopic endonasal anatomic approaches oriented to median structures (sagittal plane) before approaching paramedian (coronal plane) pathologies., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: Mucopolysaccharidosis type VI is a rare autosomal recessive storage disorder, caused by deficiency of arylsulfatase B. Data on neurological involvement in mucopolysaccharidosis type VI patients under enzyme-replacement therapy are limited. This study explores the neurological and magnetic resonance imaging findings in a sample of mucopolysaccharidosis type VI patients receiving enzyme-replacement therapy., Methods: We performed a cross-sectional study including six patients with biochemical confirmation of mucopolysaccharidosis type VI and at least 105 consecutive weeks (two years) receiving intravenous enzyme-replacement therapy. The protocol included a comprehensive clinical examination, brain and spinal cord magnetic resonance imaging for all subjects., Results: Overall, cognition was spared, while we found presence of hearing impairment, increasing in deep tendon reflexes and deep sensation reduction in three patients. In addition to the classical abnormalities related to other types of mucopolysaccharidosis, imaging studies demonstrated morphological changes in anatomy of middle cranial fossa and sella shape. Even in asymptomatic or mild compromised patients, spinal cord compression was found. In four patients we noticed atlantoaxial joint subluxation and three had cervical spinal stenosis. Degenerative processes involving vertebral column, including discal protrusion and axis abnormalities, were present in all patients., Conclusions: Neuroaxis involvement was a universal finding and neurological examination might not predict the severity of the disease in course. Image studies should not be performed according exclusively clinical parameters for these patients, once we have demonstrated that neurological involvement may be silent in these patients., (Copyright © 2013 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Objective: Endoscopy has provided a less invasive approach to skull base surgery, mainly through endonasal routes, but has been limited in its applications due to potential complications. The aims of this study were to evaluate the feasibility of the purely endoscopic extradural transcranial approach to lateral and central skull base through a subtemporal keyhole and to better understand potential distortions of the related anatomy via endoscopy., Methods: Ten fresh cadaver heads were studied with 4-mm 0° and 30° endoscopes to develop the surgical approach and to identify surgical landmarks., Results: The endoscopic extradural subtemporal approach was divided into 3 sections after exposure of the extradural space in the middle cranial fossa: 1) exposure of the lateral wall of the cavernous sinus and the preauricular infratemporal fossa; 2) anterior petrosectomy and posterior cranial fossa exploration; and 3) unroofing of the tympanic cavity and exposure of the facial nerve. This keyhole endoscopic technique clearly visualized anatomical landmarks of the lateral and central skull base via an extradural subtemporal route., Conclusions: The endoscopic extradural subtemporal approach was feasible. This approach could display a wide range of lateral and central skull base structures with minimal invasiveness. The use of extradural space would be key to performing safe and effective endoscopic skull base surgery., (Copyright © 2013 Elsevier Inc. All rights reserved.)