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The developing sphenoid is regarded as a median cartilage mass (basisphenoid [BS]) with three cartilaginous processes (orbitosphenoid [OS], ala temporalis [AT], and alar process [AP]). The relationships of this initial configuration with the adult morphology are difficult to determine because of extensive membranous ossification along the cartilaginous elements. The purpose of this study was therefore to evaluate the anatomical connections between each element of the fetal sphenoid and adult morphology. Sagittal sections from 25 embryos and fetuses of gestational age 6-34 weeks and crown-rump length 12-295 mm were therefore examined and compared with horizontal and frontal sections from the other 25 late-term fetuses (217-340 mm). The OS was identified as a set of three mutually attached cartilage bars in early fetuses. At all stages, the OS-post was continuous with the anterolateral part of the BS. The BS included the notochord and Rathke's pouch remnant in embryos and early fetuses. The dorsum sellae was absent from embryos, but it protruded from the BS in early fetuses before a fossa for the hypophysis became evident. Although not higher than the hypophysis at midterm, the dorsum sellae elongated superiorly after gestational age 25 weeks. In early fetuses, the AP was located on the side immediately anterior to the otic capsule. The AT developed on the side immediately posterior to the extraocular rectus muscles. At late term, the greater wing was formed by membranous bones from the AT and AP. The AT and AP formed a complex bridge between the BS and the greater wing. A small cartilage, future medial pterygoid process (PTmed) was located inferior to the AT in early fetuses. At midterm, one endochondral bone and multiple membranous bones formed the PTmed. The lateral pterygoid process (PTlat) was formed by a single membranous bone plate. Therefore, we connected fetal elements and the adult morphology as follows. (1) Derivative of the OS makes not only the lesser wing but also the anterior margin of the body of the sphenoid. (2) Derivatives of the BS are the body of the sphenoid including the sella turcica and the dorsum sellae. (3) Most of the greater wing including the foramen rotundum and the foramen oval originate from the AT and AP and multiple membranous bones. (4) The PTmed originate from endochondral bones and multiple membranous bones, while the PTlat derive from a single membranous bone.

BACKGROUND: Tuberculum sellae meningiomas are deep-seated tumors difficult to access, located in close relation with important neurovascular structures. While the transsphenoidal approach is linked to specific complications, the different reported transcranial approaches are associated with advantages and drawbacks due to the respective angle of attack, with some areas adequately exposed and others partially hidden. METHOD: We report the technical aspects of the anterior interhemispheric approach we practice. CONCLUSION: This approach has the advantage of providing full control over all the vasculo-nervous structures involved and of allowing access to the medial aspect of both optic canals tangentially to the dorsum sellae.

The pretemporal transcavernous approach (PTA) provides optimal exposure and access to the basilar artery (BA); however, the PTA can be invasive when vital neurovascular structures are mobilized. The goal of this study was to evaluate mobilization strategies to tailor approaches to the BA. After an orbitozygomatic craniotomy, 10 sides of 5 cadaveric heads were used to assess the surgical access to the BA via the opticocarotid triangle (OCT), carotid-oculomotor triangle (COT), and oculomotor-tentorial triangle (OTT). Measurements were obtained, and morphometric analyses were performed for natural neurovascular positions and after each stepwise expansion maneuver. An imaginary line connecting the midpoints of the limbus sphenoidale and dorsum sellae was used as a reference to normalize the measurements of BA exposure and to facilitate the clinical applicability of this technique. In the OCT, the exposed BA segment ranged from − 1 ± 3.9 to + 6 ± 2.0 mm in length in its natural position. In the COT, the accessible BA segment ranged from − 4 ± 2.3 to − 2 ± 3.0 mm in length in its natural position. Via the OTT, the accessible BA segment ranged from − 7 ± 2.6 to − 5 ± 2.8 mm in length in its natural position. In the OCT, COT, and OTT, a posterior clinoidectomy extended the exposure down to − 6 ± 2.7, − 8 ± 2.5, and − 9 ± 2.9 mm, respectively. This study quantitatively evaluated the need for the expansion maneuvers in the PTA to reach BA aneurysms according to the patient’s anatomical characteristics.

BackgroundSkull base chordomas (SBCs) are rare malignant bone tumors with dismal long-term local control. Endoscopic endonasal surgeries (EESs) are increasingly adopted to resect SBCs recently. Gross total resection (GTR) favors good outcomes. However, the SBCs often invade the skull base extensively and hide behind vital neurovascular structures; the tumors were challenging to remove entirely. To improve the GTR, we established a surgical strategy for EES according to the tumor growth directions.MethodsA total of 112 patients with SBCs from 2018 to 2019 were classified into the derivation group. We retrospectively analyzed their radiologic images and operation videos to find the accurate tumor locations. By doing so, we confirmed the tumor growth directions and established a surgical strategy. Fifty-five patients who were operated on in 2020 were regarded as the validation group, and we performed their operations following the surgical strategy to verify its value.ResultsIn the derivation group, 78.6% of SBCs invade the dorsum sellae and posterior clinoid process region. 62.5% and 69.6% of tumors extend to the left and right posterior spaces of cavernous ICA, respectively. 59.8% and 61.6% of tumors extend to the left and right posterior spaces of paraclival and lacerum ICA (pc-la ICA), respectively. 30.4% and 28.6% of tumors extended along the left and right petroclival fissures that extend toward the jugular foramen, respectively. 30.4% of tumors involved the foramen magnum and craniocervical junction region. The GTR was achieved in 60.8% of patients with primary SBCs in the derivation group. Based on the tumors’ growth pattern, pituitary transposition and posterior clinoidectomy techniques were adopted to resect tumors that hid behind cavernous ICA. Paraclival ICA transposition was used when the tumor invaded the posterior spaces of pc-la ICA. Lacerum fibrocartilage resection and eustachian tube transposition may be warranted to resect the tumors that extended to the jugular foramen. GTR was achieved in 75.0% of patients with primary SBCs in the validation group.ConclusionBesides the midline clival region, the SBCs frequently grow into the eight spaces mentioned above. The surgical strategy based on the growth pattern contributes to increasing the GTR rate.

Background: The bridging of sella turcica and dental anomalies have common embryonic origins and underlying genetic basis. Many studies have linked sella turcica bridging to developmental syndromes affecting the craniofacial region, and local dental anomalies. The purpose of this study was to determine the association between the bridging of the sella turcica and hypodontia. Methods: The clinical records along with lateral cephalograms and orthopantamograms of 40 hypodontic patients as study sample (12 males and 28 females; mean age 13.9±2.5 years) and of 120 non-hypodontic patients as control groups (58 males and 62 females; mean age 14.1±1.8 years) matched for age and gender to the study sample who came for orthodontic treatment, were collected from orthodontic clinics. Panoramic radiographs were evaluated for hypodontia. In order to quantify the extent of a sella turcica bridge on lateral cephalogram, the contour of the pituitary fossa from the tip of the dorsum sellae to the tuberculum sella was traced and extent of bridging was categorized by standardize scoring scale using the comparative measurement of sella length and diameter. Results: The presence of complete bridging (17.5%) and partial bridging (55%) in patients with hypodontia were more than complete bridging (5%) and partial bridging (37.5%) in patients without hypodontia (controls). The association between the degree of bridging and hypodontia was statistically significant according to chi-square statistics (p=0.001). There were no statistical differences between the degree of calcification and gender (p=0.616). Conclusions: The prevalence of sella turcica bridging inpatient with hypodontia was more and showed a significant association between sella turcica bridging and hypodontia. There is no dependence between the degree of calcification and gender. As the sella turcica bridge appears early in life, it should alert clinicians as a useful diagnostic predictor to the possible development of tooth anomalies later in life.

Background The primitive trigeminal artery (PTA) is the most common and the largest persistent carotid-basilar anastomosis. Primitive trigeminal artery variants (PTAVs) are anastomoses between the internal carotid artery and cerebellar arteries. These vessels pose a risk of hemorrhagic or ischemic complications during neurosurgical procedures in the parasellar and intrasellar regions. The aim of this study was to determine the prevalence of both PTA and PTAVs and their clinically important anatomic features. Methods Major electronic databases were thoroughly searched for studies on PTA and PTAV. References in the included articles were also evaluated. Data regarding prevalence, laterality, origin, course patterns, and associated anomalies were extracted and pooled into a meta-analysis. Results A total of 39 studies (110,866 patients) were included in the meta-analysis. The total pooled prevalence estimate of PTA and PTAVs combined was 0.4% (95% confidence interval [CI], 0.3–0.5). Individually, PTA was present in 0.3% of patients and PTAV in 0.2%. Both arteries most often originated from the C4 internal carotid artery and took a course lateral to the dorsum sellae. The anterior inferior cerebellar artery type was the predominant PTAV (72.1%). Basilar artery hypoplasia was found in 42.5% of patients with a PTA. Conclusions PTA and PTAVs are rare vessels, but they are clinically important because they can contribute to trigeminal neuralgia. Knowledge of the potential course of these arteries is essential in neuroradiology and neurosurgery, especially in minimally invasive procedures such as the endoscopic endonasal transsphenoidal approach to the pituitary gland and the percutaneous gasserian ganglion procedure.

OBJECTIVEThe expanded endoscopic endonasal approach (EEA) has shown promising results in treatment of midline skull base lesions. Several case reports exist on the utilization of the EEA for treatment of aneurysms. However, a comparison of this approach with the classic transcranial orbitozygomatic approach to the basilar apex (BAX) region is missing.The present study summarizes the results of a series of cadaveric surgical simulations for assessment of the EEA to the BAX region for aneurysm clipping and its comparison with the transcranial orbitozygomatic approach as one of the most common approaches used to treat BAX aneurysms.METHODSFifteen cadaveric specimens underwent bilateral orbitozygomatic craniotomies as well as an EEA (first without a pituitary transposition [PT] and then with a PT) to expose the BAX. The following variables were measured, recorded, and compared between the orbitozygomatic approach and the EEA: 1) number of perforating arteries counted on bilateral posterior cerebral arteries (PCAs); 2) exposure and clipping lengths of the PCAs, superior cerebellar arteries (SCAs), and proximal basilar artery; and 3) surgical area of exposure in the BAX region.RESULTSExcept for the proximal basilar artery exposure and clipping, the orbitozygomatic approach provided statistically significantly greater values for vascular exposure and control in the BAX region (i.e., exposure and clipping of ipsilateral and contralateral SCAs and PCAs). The EEA with PT was significantly better in exposing and clipping bilateral PCAs compared to EEA without a PT, but not in terms of other measured variables. The surgical area of exposure and PCA perforator counts were not significantly different between the 3 approaches. The EEA provided better exposure and control if the BAX was located ≥ 4 mm inferior to the dorsum sellae.CONCLUSIONSFor BAX aneurysms located in the retrosellar area, PT is usually required to obtain improved exposure and control for the bilateral PCAs. However, the transcranial approach is generally superior to both endoscopic approaches for accessing the BAX region. Considering the superior exposure of the proximal basilar artery obtained with the EEA, it could be a viable option when surgical treatment is considered for a low-lying BAX or mid–basilar trunk aneurysms (≥ 4 mm inferior to dorsum sellae).

This study aimed to investigate the frequency of squamous suture (SqS) obliteration, to estimate the involvement of the major calvarial sutures and those surrounding the temporal squama, and to inspect the neuro- and basicranium for deformities. A series of 211 dry skulls of contemporary adult males were macroscopically observed. The skulls with closed SqS were scanned using an industrial µCT system. Digital morphometry of the skulls with obliterated SqS was performed by recording the 3D coordinates of anatomic landmarks and calculation of linear distances, angles and indices. Obliteration of SqS was observed in 3 (1.42%) skulls. One skull showed bilateral SqS obliteration. The other two cases were unilateral, one right-sided and one left-sided. SqS obliteration seems to be co-ordinated with the closure of the parietomastoid suture, partially related to the closure of the occipitomastoid, sphenoparietal and sphenofrontal sutures, and independent from the closure of the sphenosquamosal suture and the major calvarial sutures. No severe disproportions in the skull configuration were observed in the three investigated cases. The major differences in the complimentary hemicrania concern the parietal and occipital parts of the skull vault. Dorsum sellae erosion, an indicator for raised intracranial pressure, was observed in all three cases.

Basilar tip aneurysm clipping is technically challenging because of the depth of operative corridor, rarity in presentation, and important perforators supplying deep, critical structures. Two major approaches to basilar tip aneurysms include (1) a frontotemporal (transorbital) trans-sylvian approach for most aneurysms and (2) a modified subtemporal approach for aneurysms with low-lying necks. A 53-yr-old woman presented to our institution with a large unruptured basilar tip aneurysm notable for a low, broad neck (6.4 mm). After discussion of risks and benefits of endovascular vs surgical options, the patient consented to operative intervention. She underwent a right frontotemporal craniotomy with zygomatic osteotomy, intradural petrous apicectomy, elective sectioning of the fourth cranial nerve (CN IV), and intracavernous removal of the dorsum sellae and posterior clinoid process to provide more space for aneurysm dissection. After temporary clipping of the basilar artery, the perforating arteries were dissected free from the aneurysm and the aneurysm occluded with 2 fenestrated clips. Important technical nuances of the approach include (1) achieving ample working room for temporary occlusion aneurysm dissection, (2) careful dissection of the perforators and contralateral P1, and (3) utilization of 2 fenestrated clips to accommodate and preserve the ipsilateral P1 segment. Postoperative angiogram showed complete aneur-ysmal occlusion. Postoperatively, the patient demonstrated mild cognitive impairment and a right CN IV palsy. At 6-wk follow-up, cognition recovered to normalcy. More recently, at 12-mo follow-up, the patient noted intermittent diplopia. Formal neuro-ophthalmologic assessment confirmed persistence of a CN IV palsy treated with prism lenses but no other neurological deficits.

Sphenoid bone may be affected by different variants of pneumatisation, which have a relevant importance from a clinical and surgical point of view. The description of such variants in different populations may give useful information. However, few articles describe the variability of sphenoid pneumatised structures and none of them focuses on Northern Italian population. Variants of pneumatisation of sphenoid bone were described in a sample of 300 Northern Italian patients who underwent a CT scan. More than fifty-seven percent of patients showed a form of anatomical variant: the most common form was the pneumatised pterygoid processes (39.6%), followed by dorsum sellae (32.9%) and clinoid processes (20.3%), without statistically significant differences between males and females (p > 0.01). In 26.3% of patients, a combined pneumatisation of these three structures was observed, being the combination pterygoid processes-dorsum sellae the most frequent (11.3%). In 9.3%, all the three sphenoid structures were affected. This article is the first description of the prevalence of different variants of pneumatisation in a Northern Italian population: the occurrence of such forms has to be acknowledged for their possible clinical and surgical consequences.

Surgical treatment of lesions involving the ventral craniovertebral junction (CVJ) and the lower clivus, traditionally involved complex lateral or transoral approaches to the skull base. However, mid or upper clivus involvement requires more extensive lateral approaches. Recently, the endoscopic endonasal approach (EEA) has become the standard for upper CVJ lesions and medial clival, and a valuable alternative for those tumors extending in its upper third as well as laterally. However, the EEA is associated with an increased risk of post-operative CSF leakage and infection when the tumor is characterized by an intradural extension. Furthermore, whenever the tumor has significant lateral and/or inferior extension below the odontoid process, the chances for a complete resection decrease. To analyze the extent of exposure of a hybrid microscopic-endoscopic transcondylar antero-lateral approach to the CVJ and clival region, and to verify its effectiveness in terms of mid and upper clival access. Five silicone-injected cadaver heads were used. Following a standard antero-lateral approach, condylectomy and jugular tubercle drilling were performed, after which angled endoscopes were utilized to extend the bone resection to the clivus. A volumetric assessment of the amount of clival removal was carried out. A case of CVJ chordoma operated through this approach is presented. The hybrid antero-lateral transcondylar approach provides adequate exposure of the ventral CVJ, up to the dorsum sellae and the sphenoid sinus, the contralateral petrous apex, and the contralateral paraclival internal carotid artery (ICA). Approximately 60% of the total clival volume can be removed with this approach. The main limitation is the limited visualization of the ipsilateral paraclival ICA and petrous apex. The hybrid antero-lateral transcondylar approach is a valuable surgical option for CVJ tumor extending from C2 to the mid and upper clivus.

Aberrant course of internal carotid arteries (ICA) is rarely seen. In patients who are asymptomatic, anomalies may be detected incidentally during head and neck examination. Symptomatic patients may present with hearing loss, pulsatile tinnitus, dysphagia or a foreign body sensation in the posterior pharynx. If the retropharyngeal course of ICA remains undiagnosed, accidental biopsy or surgical intervention can result in life threatening complications. The abnormal course of ICA results from a complex defect in embryological development and is unlikely to be an acquired process. Previously, bilateral and unilateral agenesis, hypoplastic, retropharyngeal tortuous ICA and kissing sellar ICA have been described in literature. We used various imaging techniques to describe this first case of fused ICA with an aberrant course through the clivus and dorsum sellae. The patient also presented with patulous Eustachian tubes on both the left and right side.

Aim To assess the feasibility of using an endoscopic-assisted lateral supraorbital (LSO) approach and an endoscopic endonasal transclival approach (EETA) for basilar apex (BAX) aneurysms. Material and methods Ten cases with LSO approaches, with or without posterior clinoidectomy and endoscopic assistance, and 10 cases with EETA, with or without drilling of the dorsum sellae, were performed on 20 cadaveric heads. Anatomical exposure and surgical freedom at the BAX were evaluated. Results Anatomical exposure provided by the LSO approach was limited to the BAX and ipsilateral posterior cerebral artery (PCA) and increased with a mean value of 5.0 mm after posterior clinoidectomy; the basilar artery, contralateral PCA, and superior cerebellar arteries (SCAs) were visualized in all cases. Accordingly, surgical freedom was larger. Endoscopic assistance provided a significant increase in basilar artery exposure; however, surgical freedom did not increase markedly. The main advantage of EETA was the greatest exposure of the basilar artery. With drilling of the dorsum sellae, anatomical exposure increased by a mean value of 3.4 mm, and provided the greatest amount of surgical freedom and visualization of the basilar artery terminal bifurcation and of the SCAs in all cases. Conclusion The endoscopic-assisted LSO approach and the EETA may represent a feasible approach for treatment of BAX aneurysms lying within 5.0 mm below and within 3.4 mm above the dorsum sellae.

Background: Pituitary gland dysfunction might be predicted by examining the alteration of Sella turcica during the routine radiological examination of lateral cephalogram. Aim: The study aimed to analyze the variation in size and shape of sella turcica according to age and gender on lateral cephalogram among the people in the south zone of Chennai city. Materials and Method: A series of lateral cephalogram images from 200 patients comprising 94 males and 106 females were collected retrospectively from archives in the database. The shape and size of sella turcica were measured digitally. Statistical analysis was done using the Chi-square test and unpaired sample t-test. Results: The frequency of distribution of shapes of sella turcica among the people in Chennai city was 46% normal followed by 15.5% irregular dorsum sellae, 14.5% pyramidal shape, 11.5% bridging, 7% oblique anterior wall, 5.5% double contour. The length and depth of Sella turcica was greater in males when compared with that of the females which were statistically significant (P < 0.01). The depth and diameter were higher in the 10–20 years age group than the 20–30 year age group, which was statistically significant (P = 0.01). Conclusion: The size of Sella turcica alters between different age groups and gender. Variations in the shape of Sella turcica were present in nearly half of the individuals in the present study. Thus, the morphology of Sella turcica should be assessed as a part of routine radiographic examination.

Sellar spine, a bony spur extending anteriorly from the dorsum sellae, is a very rare anatomical variant. Several hypotheses regarding its etiology have been proposed, including the strongly supported theory of a cephalic ossified notochordal remnant. Sellar spine is usually detected incidentally in patients who have no definite symptoms, but several cases have reportedly accompanied endocrinopathies such as precocious puberty, hypopituitarism, or galactorrhea/oligomenorrhea. However, no published reports have described sellar spine in a patient with Cushing’s syndrome. We herein report a case of sellar spine detected during the evaluation of Cushing’s disease in a 29-year-old woman who underwent inferior petrosal sinus sampling, computed tomography, magnetic resonance imaging, and exploratory surgery. There was no evidence of a pituitary microadenoma, but a sellar spine was present in the operative field. Thus, the sellar spine might have caused Cushing’s syndrome in this case, although the exact mechanism is unknown.

We describe a nearly complete skull and mandible of a subadult of Euclastes wielandi, a pan-cheloniid turtle recently recovered at the Jean and Ric Edelman Fossil Park at Rowan University in Mantua Township, New Jersey, which yields new information about the osteology, ontogeny, and intraspecific variation of this taxon. The specimen was collected from the earliest Danian Main Fossiliferous Layer (MFL) of the Hornerstown Formation. Although discovered immediately adjacent to remains of two pleurodires, Taphrosphys sulcatus and Bothremys sp., the skull and mandible can be definitively assigned to Pan-Cheloniidae based on its V-shaped basisphenoid and rod-like rostrum basisphenoidale. Among three pan-cheloniid taxa known from the MFL, the specimen is assigned to Eu. wielandi based on its low skull with dorsally-directed orbits, symphyseal swelling in the mandibular triturating surface, and high dorsum sellae. Comparisons with other specimens of Eu. wielandi and adults and juveniles of other pan-cheloniids revealed variations in the type and timing of cranial ontogenetic changes in the clade, as well as anatomical traits subject to intraspecific variation, such as the depth of the sella turcica, paths of the foramina nervi hypoglossi, and development of a precolumellar fossa. The relative contribution of the frontal to the orbital margin and precise path of the prefrontal-supraorbital scale sulcus are subject to individual variation in Eu. wielandi, as well as ontogenetic variation and bilateral asymmetry in other cryptodirans, signifying that the widespread use of frontal retraction in taxon diagnoses and as a phylogenetic character should be reconsidered. As in multiple other taxa, the mandibular triturating surface expands through growth in Eu. wielandi, demonstrating that increased durophagy with age was a common life strategy among Cryptodira.

Patient: Male, 53 Final Diagnosis: Clivus chordoma Symptoms: Pain the eye Medication: — Clinical Procedure: — Specialty: Radiology Objective: Rare disease Background: The clivus is a depression in the anterior occipital bone of the skull base, posterior to the dorsum sellae, at the junction with the sphenoid bone. Chordoma is a rare tumor arising from embryonic remnants of the notochord and can be locally aggressive with a tendency to recur. The optimal management of this rare tumor remains controversial. A report of a case of recurrent chordoma of the clivus is presented to illustrate the value of volumetric three-dimensional (3-D) reconstruction with computed tomography (CT) and magnetic resonance imaging (MRI) to determine optimal surgical management. Case Report: A 53-year-old man presented with pain in the right orbital cavity, right proptosis, swelling of the right cheek, and bilateral loss of vision. He also had adrenal insufficiency. CT and contrast-enhanced (gadolinium) T1-weighted MRI with multiplanar acquisition were performed with volumetric 3-D reconstruction of the tumor, to increase the chances of treatment success. Surgical resection was performed to remove the tumor and reduce the risk of recurrence. Histology of the tumor was consistent with chordoma, supported by positive immunohistochemical staining for S-100 and epithelial membrane antigen (EMA). Conclusions: This report highlighted the value of 3-D volume imaging in the diagnosis and treatment planning in a rare case of recurrent chordoma of the clivus. Analysis of tumor volume may be an indicator of the efficacy of surgery, complementing the Response Evaluation Criteria In Solid Tumors (RECIST) system and as a valuable tool to predict treatment outcome.

Background and importance Access to a dorsum sellae meningioma is difficult. A transcranial approach, such as a pterional, subtemporal, or transpetrosal method, often requires significant brain retraction and crossing of cranial nerves to access this region. We present here a successful purely endoscopic endonasal transpituitary gland approach for resection of a growing dorsum sellae meningioma. Clinical presentation A 74-yr-old woman came to us with dizziness. Magnetic resonance imaging (MRI) demonstrated a mass on the dorsum sellae around the left posterior clinoid. Follow-up MRI examinations over a 3-yr period showed a gradual increase in size of the mass and increasing compression of the left peduncle. To avoid brain retraction, an endoscopic endonasal approach was selected for tumor removal. With this method, we went through the pituitary gland by splitting it, and drilled into the dorsum sellae and clivus to access the front of the tumor. Gross total removal was safely achieved. The patient was asymptomatic and had normal pituitary function after the operation. Conclusion The present endoscopic endonasal transpituitary gland approach allowed for safe resection of a dorsum sellae meningioma. We consider it to be less invasive for patients because of no need for brain retraction.

Purpose: Assessment of sphenoid sinus (SS), posterior clinoid process (PCP), and dorsum sellae (DS) pneumatisation is significant when planning surgical approaches both to intra- and extrasellar pathologies. The authors analysed pneumatisation of the SS, with particular attention paid to pneumatisation of the PCP and DS. Material and methods: The study was based on 100 computed tomography angiography examinations. SS, PCP, and DS pneumatisation grades were assessed using the classification system proposed by Hardy. The analyses were conducted in sagittal planes: midline plane (MP), sagittal posterior clinoid plane right (SPCP-R), and sagittal posterior clinoid plane left (SPCP-L). The occurrence of the highest pneumatisation grade (IVB according to Hardy), which encompasses DS and PCP, prompted the authors to conduct a further analysis in the coronal plane. In this way, seven DS and PCP pneumatisation symmetry types were identified. Results: In the MP and SPCP-R, the most frequent pneumatisation grade was grade III (41% and 38%, respectively). In the SPCP-L, grade IVA prevailed (41%). Grade IVB was found in 12% of the SPCP-R images, 10% of the SPCP-L images, and in 12% of the MP images. Consistent pneumatisation grades in all analysed planes were found for 64% of cases. This was usually grade III noted in 28% of cases. Conclusions: SS pneumatisation is characterised by considerable individual variability. There are a number of SS pneumatisation classification systems, but the system proposed by Hardy is the most useful for assessment of DS and PCP pneumatisation. Grade III of SS pneumatisation is the most common. Pneumatisation encompassing DS and PCP was found in 10-12% of cases.

Chordoma, a rare bone tumor that occurs along the spine, has led scientists on a fascinating journey of discoveries. In this historical vignette, the authors track these discoveries in diagnosis and treatment, noting events and clinicians that played pivotal roles in our current understanding of chordoma. The study of chordoma begins in 1846 when Rudolf Virchow first observed its occurrence on a dorsum sellae; he coined the term “chordomata” 11 years later. The chordoma’s origin was greatly disputed by members of the scientific community. Eventually, Müller’s notochord hypothesis was accepted 36 years after its proposal. Chordomas were considered benign and slow growing until the early 1900s, when reported autopsy cases drew attention to their possible malignant nature. Between 1864 and 1919, the first-ever symptomatic descriptions of various forms of chordoma were reported, with the subsequent characterization of chordoma histology and the establishment of classification criteria shortly thereafter. The authors discuss the critical historical steps in diagnosis and treatment, as well as pioneering operations and treatment modalities, noting the physicians and cases responsible for advancing our understanding of chordoma.

A 69-year-old female with incidental diagnosis of a dorsum sellae meningioma had shown significant tumor growth after initial conservative management. The procedure started with a microscopic sublabial transsphenoidal approach to the sella and the suprasellar space. Due to limitations to a safe dissection and removal of the retrosellar component, the surgery was converted to a purely endoscopic endonasal approach with left hemi-transposition of the pituitary gland, followed by drilling of the dorsum sellae and removal of the left posterior clinoid process. A complete tumor resection was achieved, and a multilayer skull base reconstruction was performed without complications.The video can be found here: https://youtu.be/BEolyK-To_A.

This video demonstrates a surgical technique of resecting dorsum sellae meningioma using a combined interhemispheric translamina terminalis approach and pterional approach with clinoidectomy. The tumor, 5 cm in maximum diameter, originated from the dorsum sellae, compressed the third ventricle and the midbrain, and displaced the pituitary stalk ventrally. Feeding arteries of the tumor were bilateral meningohypophyseal trunks, mainly from the right side. The authors performed devascularization of the tumor via a right pterional approach following frontotemporal craniotomy, and debulking of the tumor via an interhemispheric translamina terminalis approach following bifrontal craniotomy. These procedures with two separate craniotomies enabled safe and effective resection of the tumor.The video can be found here: https://youtu.be/DEnKOC5zQ_M.

Rathke’s cleft cyst is a cystic disease that occurs in the sella turcica or, occasionally, in the suprasellar area. An ectopic Rathke’s cleft cyst is extremely rare, and its nature is less well understood. The authors report the case of a 14-year-old girl who presented with a growing cystic lesion in the prepontine cistern, immediately behind the dorsum sellae. Preoperative imaging and intraoperative investigation showed part of the cyst wall continuing into the dorsum sellae, to the pituitary gland. The cisternal portion of the cyst wall was totally resected via a right subtemporal approach. Histopathological examination of the cyst wall showed a monolayer of ciliated cells, identical to those of Rathke’s cleft cyst. To the best of the authors’ knowledge, this represents the first pediatric case of Rathke’s cleft cyst occurring in the prepontine cistern.

Psephoderma alpinum is an armoured, durophagous placodont known from the alpine Late Triassic. Here we present a new, well-preserved isolated skull discovered in the Alplihorn Member (Late Norian–Early Rhaetian) of the Kossen Formation, Schesaplana Mountain, which straddles the Swiss/Austrian border. Micro-computed tomographic (µCT) scanning was used to create an accurate osteological reconstruction of the specimen, the first time this has been conducted for Psephoderma. We thus clarify disputed anatomical features from previous descriptions, such as a lack of a lacrimal and a pineal foramen that is enclosed by the parietal. We also present the first description based on µCT data of the lateral braincase wall, sphenoid region and some cranial nerve canals for Psephoderma, with the location of the hypophyseal seat, cerebral carotid foramina, dorsum sellae, prootic foramen, lacrimal foramen, as well as all dental foramina being described. This specimen represents the first skull of Psephoderma recovered in Switzerland, and features such as poorly-sutured braincase elements and its relatively small size compared to other known specimens may indicate that it was a sub-adult.

A membrana de Liliequist, de maneira simplista e sucinta, pode ser entendida como uma projeção formada pela aracnoide que se estende do dorso da sela turca aos corpos mamilares. Apesar de se tratar de uma estrutura anatômica bem conhecida pelos neurocirurgiões, muitos radiologistas não a conhecem ou não valorizam seu estudo. A avaliação por imagem desta membrana é factível e pode ser interessante para o melhor planejamento pré-operatório, avaliação pós-operatória de terceiro-ventriculostomias e entendimento dos cistos aracnoides suprasselares e hemorragias perimesencefálicas. Ilustramos neste artigo os aspectos anatômicos da membrana, sobretudo do ponto de vista de imagem, além de suas possíveis implicações clinicocirúrgicas. In a simplistic and succinct way, Liliequist membrane may be understood as a projection formed by an arachnoid membrane extending from the dorsum sellae to the mammillary bodies. In spite of being well known to neurosurgeons, many radiologists neither know this anatomical structure nor give importance to its study. The imaging evaluation of this membrane is feasible and may be interesting for a better preoperative planning; postoperative evaluation of third ventriculostomies; and understanding of suprasellar arachnoid cysts and perimesencephalic hemorrhage. The present article illustrates the anatomy of the membrane, with emphasis on imaging findings, besides describing its possible clinical and surgical implications.

The braincase of the marine turtle Syllomus aegyptiacus (Calvert Formation, Virginia, Middle Miocene) is described and figured in detail for the first time. It reveals a ventral crest on the basisphenoid, a high dorsum sellae, an almost subequal diameter of the canals for the internal and lateral carotid arteries at a cross break and a canalis caroticus lateralis and internus that are still far separated from each other at level of the dorsum sellae. The braincase is compared to other known braincases of fossil and extant chelonioid turtles.

A 63-year-old man presented with sexual dysfunction of 6-year duration, 5-year history of bilateral vision loss, and left nasal obstruction for 3 years. Brain computed tomography and magnetic resonance imaging showed a large mass lesion in the saddle area and extending upward to the dorsum sellae, bilateral cavernous sinus, and suprasellar region, and down into the sphenoid sinus and nasal cavity; the optic nerves and optic chiasm were elevated upward and compressed. Endocrine tests indicated that all serum level of anterior pituitary hormones decreased. The preoperative diagnosis included invasive pituitary adenoma, chordoma, osteosarcoma, chondrosarcoma, and craniopharyngioma. The tumour was subtotally removed through transsphenoidal approach. Histopathology examination revealed a chondroma. Postoperatively, the patient was stable and his visual acuity and visual field defect improved and his pituitary function return to normal except for hypothyroidism.

Morphological studies of the braincase and cranial endocast of fossil crocodylians, especially gavialids, are scarce. Here, we present a detailed description of the neuroanatomy of Gryposuchus neogaeus from the Miocene of Argentina, based on CT scans. The cranial endocast is sub-horizontal and the angle formed between the mid-brain and the hind-brain is poorly marked. When compared with Gavialis gangeticus, the mid-brain of G. neogaeus is relatively shorter, although the distribution of cranial nerves is similar. In the floor of the endocranial cavity, posterior to the dorsum sellae, there is a median foramen that leads into a canal that runs anteroventrally through the basisphenoid to penetrate the posterior wall of the pituitary fossa (open foramen for the basilar artery?). The same structure is present in G. gangeticus, but is absent in other living crocodylians, suggesting a potential synapomorphy of Gavialoidea. The pneumaticity of the skull roof and the lateral branches of the pharyngotympanic system in G. neogaeus are markedly reduced when compared with the extant species. Comparisons with the living Gavialis indicate that the pattern of braincase morphology of Gavialidae was present in the Miocene; however, the internal morphology, including brain shape, pneumaticity of the skull roof and basicranium, is different in the two species. This work is the first step to understand the variation of the neuroanatomy in this group of archosaurs and its palaeobiological implication., Facultad de Ciencias Naturales y Museo

Background Basilar tip aneurysms are one of the most complex vascular lesions to treat surgically because of their location, depth of the approach, and close proximity of vital neurovascular structures such as the mesencephalon, cranial nerves, perforating arteries to the thalamus. There are different surgical approaches utilized to reach basilar tip aneurysms, namely, pterional, pretemporal, orbitozygomatic, subtemporal, and anterior petrosectomy. Each of them has its advantages and limitations. Methods In this paper, we present our personal experience with the use of subtemporal approach. The technique is described in detail including its nuances and potential pitfalls. Results The subtemporal approach is indicated for basilar tip aneurysms located at the level of the floor of the sella turcica to 1 cm above the dorsum sellae. Conclusion Subtemporal approach offers good surgical corridor for the management of these complex vascular lesions.

Anatomical variations in the shape and dimension of the dorsum sellae and posterior clinoid process are common. Most textbooks describe its shape as a median rectangular plate, a square plate, or a transverse ledge on a slope behind the sella turcica (hypophyseal fossa). This work aims to study the dorsum sellae of human skull. One hundred and twenty five dried adult human skulls, irrespective of age, were used for the study. Detailed features of the dorsum sellae were noted and classified into five types: crest like, thin plate, frail quadrilateral plate, heavy square plate, thick elongated plate. Fusion of the posterior and middle clinoid processes in one (unilateral) and all the clinoid processes (anterior, middle, and posterior) in three skulls (unilateral in one, bilateral in two) were also noticed. Findings are discussed in the light of the literature.

Cavernous segment internal carotid artery (CSICA) injury during endoscopic transsphenoidal surgery for pituitary tumor is rare but fatal. The aim of this study is to investigate anatomical relationship between pituitary macroadenoma and corresponding CSICA using quantitative means with a sense to improve safety of surgery. In this retrospective study, a total of 98 patients with nonfunctioning pituitary macroadenomas undergoing endoscopic transsphenoidal surgeries were enrolled from 2005 to 2014. Intercarotid distances between bilateral CSICAs were measured in the 4 coronal levels, namely optic strut, convexity of carotid prominence, median sella turcica, and dorsum sellae. Parasellar extension was graded and recorded by Knosp–Steiner classification. Our findings indicated a linear relationship between size of pituitary macroadenoma and intercarotid distance over CSICA. The correlation was absent in pituitary macroadenoma with Knosp–Steiner grade 4 parasellar extension. Bigger pituitary macroadenoma makes more lateral deviation of CSICA. While facing larger tumor, sufficient bony graft is indicated for increasing surgical field, working area and operative safety.

A 50-year-old female with an incidentally diagnosed suprasellar lesion was initially managed conservatively due to the presence of an intrasellar persistent trigeminal artery going through the dorsum sellae and fundamentally forming the blood supply of the entire posterior circulation. Serial follow-up brain magnetic resonance imaging (MRI) revealed progressive enlargement of the suprasellar lesion over 4 years period. Surgery was indicated after the initial tumor growth; however, the patient refused surgery for fear of complications related to the persistent trigeminal artery. Two-and-a-half years later, she presented with deterioration of vision. Formal visual field testing revealed a right temporal field defect. Brain MRI demonstrated significantly enlarged suprasellar lesion, most consistent with tuberculum sellae meningioma, exerting mass effect on the optic apparatus.The patient underwent endoscopic endonasal resection of the lesion through a transplanum/transtuberculum approach. Intraoperatively, absence of hypertrophic McConnel arteries, hyperostosis, and the fact that the dura was soft and not under tension was against the diagnosis of tuberculum sellae meningioma. Additionally, the tumor consistency was similar to a pituitary adenoma. A complete resection was accomplished and multilayer skull base reconstruction was performed with no complications. On postoperative day 1 (POD 1), she was operated upon for the evacuation of small suprasellar hematoma associated with vision deterioration. Histopathological examination confirmed the diagnosis of atypical pituitary adenoma with K i-67 labeling index of 4 to 5%. The patient ultimately recovered well with improved vision, and was discharged on POD 4 with no new neurological deficits. At 4 years follow-up, her vision was normalized and brain MRI showed no residual or recurrent lesion.The link to the video can be found at: https://youtu.be/QZmzctjAEbw.

This study was conducted to investigate the radiological anatomy of the posterior clinoid process (PCP) to highlight preoperative awareness of its variations and its relationships to other skull base landmarks. The PCPs of 36, three-dimensional computed tomographic cadaveric heads were evaluated by studying the gross anatomy of the PCP and by measuring the distances between the PCP and other skull base anatomical landmarks relevant to transnasal or transcranial skull base approaches. PCP variations were found in five specimens (14%): in two the dorsum sellae was absent, in one the PCP and the anterior clinoid process (ACP) were connected unilaterally and in two bilaterally. The mean distance between the right/left PCP and the crista galli was 45.14 ± 4.0 standard deviation (SD_/46.24 ± 4.5 SD, respectively, while the distance to the middle point of the basion at the level of the foramen magnum was 40.41 ± 5.1 SD/41.0 ± 5.2 SD, respectively. The mean distance between the PCP and the ACP was 12.03 ± 3.18 SD on the right side and 12.11 ± 2.77 SD on the left. The data provided highlights the importance of careful preoperative evaluation of the PCP and of its relationships to other commonly encountered skull base landmarks. This information may give an idea of the exposure achievable through different transcranial and transnasal approaches. This is especially relevant when neuronavigation is not available.

The posterior clinoid process, a bony prominence at the superolateral aspect of the dorsum sellae, has a strategic importance in a transcavernous approach to basilar tip aneurysms. To further optimize this microsurgical technique during posterior clinoidectomy, we performed a cadaveric study of this regional anatomy, describe a technique called dural tailoring, and report initial results in the surgical treatment of upper basilar artery (BA) aneurysm. After 10 adult cadaver heads (silicone-injected) were prepared for dissection, a posterior clinoidectomy with dural tailoring was performed. The dura overlying the upper clivus was coagulated with bipolar electrocoagulation and incised. Stripping dura off the clivus and lateral reflection then exposed the ipsilateral posterior clinoid process and dorsum sellae, thus creating a dural flap. Posterior clinoidectomy with dural tailoring was then used in seven patients with upper BA aneurysms. Our stepwise modification of the posterior clinoidectomy with dural tailoring created a flap that afforded protection of the cavernous sinus and oculomotor nerve. During surgery, there were no recorded intraoperative injuries to neurovascular structures. One patient died postoperatively from morbidity related to severe-grade subarachnoid hemorrhage. Postoperative oculomotor nerve palsy occurred in 3 patients (43%). In all cases, the nerve was anatomically preserved and partial to complete recovery was recorded during the first postoperative year. This technique effectively provided exposure of retrosellar upper basilar aneurysms in seven patients (basilar tip 43% and superior cerebellar artery aneurysms 57%). Outcomes and safety are at least equivalent to or better than basilar aneurysm surgery performed without surgical adjuncts, presumably a less complex subset.

SUMMARY The purpose of this study was to establish normative longitudinal cephalometric standards of size and to describe the morphology of the sella turcica in Norwegian males and females between 6 and 21 years of age using standardized lateral radiographic cephalograms. The subjects comprised 35 males and 37 females from the Oslo University Craniofacial Growth Archive. All were healthy Caucasians, with an Angle Class I molar and canine relationship with no apparent facial disharmony. None had undergone orthodontic therapy. The length, depth, and diameter of the sella turcica was measured and the mean values were analysed longitudinally. Comparisons between the dimensions of the sella turcica of males and females in each age group were performed using a Student’s t-test. The length of the sella turcica was almost constant throughout the observation period and the depth and diameter increased with age. No differences between males and females were detected for the depth and diameter of the sella turcica, but the length was larger in males throughout the observation period. The morphology of the sella turcica was assessed and five different morphological aberration types were identified: oblique anterior wall, sella turcica bridging, double contour of the floor, irregularity (notching) in the posterior part of the dorsum sellae, and pyramidal shape of the dorsum sellae. The female subjects had slightly more sella turcicas with aberrant morphology. These reference standards for the dimensions of the sella turcica can be used in the study of growth and development of individuals with craniofacial aberrations and syndromes.

Objective—To determine the contrast enhancement pattern of the pituitary gland in healthy dogs via dynamic computed tomography (CT). Animals—17 dogs. Procedure—With each dog in sternal recumbency, transverse CT scans were made perpendicular to the skull base from the rostral clinoid processes to the dorsum sellae. At the position of the image that contained the largest cross section of the pituitary gland, a series of 9 to 11 scans was made during and after IV injection of contrast medium (dynamic CT scans). The contrast enhancement pattern of the pituitary gland and surrounding arteries was assessed visually and by use of time-density curves. Results—After strong enhancement of the maxillary arteries, the intracavernous parts of the internal carotid arteries, and the communicating arteries of the arterial cerebral circle, there was a strong enhancement of the central part of the pituitary gland followed by enhancement of its peripheral part. On the last images of the dynamic series of the pituitary gland, the central part was hypodense, compared with the peripheral part. Time-density curves confirmed an early, strong enhancement of the central part and a delayed, less strong enhancement of the peripheral part of the gland. Conclusions and Clinical Relevance—The difference in enhancement between the central and peripheral parts of the pituitary gland was attributable to a difference in vascularization of the neurohypophysis and adenohypophysis, respectively. Distortion or disappearance of the strong central enhancement (pituitary flush) may be used for the detection and localization of pituitary abnormalities in the adenohypophysis. (Am J Vet Res 2004;65:1518–1524)

PURPOSE: To evaluate the Liliequist membrane in healthy volunteers by using three-dimensional (3D) Fourier transformation constructive interference in steady state (CISS) magnetic resonance (MR) imaging. MATERIALS AND METHODS: In 31 volunteers, the authors performed 3D CISS MR imaging. They divided the membrane into three segments: the sellar, diencephalic, and mesencephalic segments. MR images were evaluated to identify the segments, superior and inferior attachments, lateral border, and thickness of the Liliequist membrane. RESULTS: Three-dimensional CISS MR imaging depicted the sellar, diencephalic, and mesencephalic segments of the Liliequist membrane in the sagittal plane in 25 (81%), 16 (52%), and five (16%) of the 31 subjects, respectively. Transverse MR imaging depicted these segments in 24 (77%), 10 (32%), and two (6%) subjects, respectively, and coronal MR imaging depicted them in 24 (77%), 12 (39%), and two (6%) subjects, respectively. Clear attachment of the membrane to the dorsum sellae was observed in 22 (88%) of 25 subjects in whom the sellar segment was identified. Clear attachment to the mamillary body was identified in eight (50%) of 16 subjects in whom the diencephalic segment was identified. The Liliequist membrane was attached to the oculomotor nerve on seven (14%) of 50 sides of the lateral border and to the arachnoid membrane around the oculomotor nerve on 28 (56%) sides. In the sagittal plane, the thickness of the membrane was less than one-half the thickness of the third ventricle floor in 22 (88%) of 25 subjects. CONCLUSION: The Liliequist membrane can be visualized by using 3D CISS MR sequences.

Introduction: Pituitary insufficiency (PI) needs further research to optimize treatment. Growth hormone deficiency (GHD) is a subtype of PI. The purpose of the present study is to investigate the possible relationship between GHD and the anatomical position of the pons as revealed by magnetic resonance imaging (MRI) in the pediatric age group. In the current study, we developed a novel and simple index using MRI that could provide an alternative to other indexes in the classical literature. Patients and Methods: Brain MRI and clinical data of 48 children with suspected PI (22 females, 26 males; mean age 11.6 ± 2.2 years) were examined retrospectively. To estimate the location of the pons, the ratio of pons height over the axis between the dorsum sellae and the fourth ventricular hill in the sagittal plane (A) to the total height of the pons (B) was calculated (A/B). It was termed the pons ratio (PR). The PRs of children with or without a diagnosis of GHD were then compared statistically. Results: Fifteen children were diagnosed with GHD and treated with growth hormone (GH), whereas the remaining 33 were reported normal. The mean PRs of the children diagnosed with GHD and given GH treatment (0.31 ± 0.07, range: 0.18–0.42) differed significantly from those without PI (0.26 ± 0.06, range: 0.17–0.44; P = 0.018). Conclusion: There appears to be an association between GHD and decreased PR in children receiving GH treatment. Spatial measurements of posterior fossa in radiological examinations may provide additional information that is helpful in the diagnosis of suspected cases of GHD.

Introduction: Endoscopic endonasal techniques are increasingly common in a variety of skull base lesions. A major obstacle that remains to be addressed within the field is sinonasal symptomatology following endoscopic repair, with a paucity of literature describing such outcomes following resection of large anterior skull base (ASB) meningiomas. Herein, we describe our institutional experiences utilizing SNOT-22 scoring in a series of ASB meningiomas treated via an endoscopic endonasal approach. Methods: An IRB-approved retrospective study was conducted for patients undergoing endoscopic endonasal resection of ASB meningioma at Stanford University. Data were collected for 16 consecutive patients between December 2007 and July 2013. The SNOT-22 survey, a survey administered to patients comprising a variety of sinonasal symptoms and associated psychosocial consequences, has been extensively validated in previous quality-of-life measures following sinonasal pathology. Mean SNOT-22 result comparisons were made by paired sample Student t-test. To account for patients lost to follow-up, the mean score of patients who responded at each postoperative time point was compared only to the mean preoperative score in those same patients. Results: A total of 16 patients (12 females and 4 males) were studied, with mean age 54 ±10 years. Average length of follow-up was 3.1 months. Visual loss was the presenting complaint in 7 of 16 (43.5%) cases, while 4 patients presented as an incidental finding, 3 with headache, 1 with galactorrhea, and 1 with partial complex seizure. Of the 16 cases, 11 were tuberculum sellae, 4 were olfactory groove/planum sphenoidale, and 1 was at dorsum sellae. Lesions ranged from 1.9 to 5.2 cm in largest dimension, and 11 of 16 (68.75%) patients demonstrated chiasm compression on preoperative imaging. Gross total resection was achieved in 11 of 16 patients. Length of stay averaged 5.5 days (range, 3–21 days). Of the 16 patients, 6 (37.5%) complained of postoperative headache whereas 4 (25%) experienced transient postoperative diabetes insipidus. A lumbar drain was placed in 13 of 16 patients and remained in place for an average of 4 days (range, 2–5 days). At last follow-up, none of the patients had experienced CSF leak nor had any required revision. Of the 16 patients, 10 patients completed a preoperative SNOT-22 survey, whereas 12 completed at least one postoperative survey. Overall, three patients were lost to follow-up after resection. SNOT-22 scores were significantly worse at 1 month after resection compared with preoperative scores (n = 6, p = 0.012). However, scores were not significantly different within subjects between preoperative assessment and last follow-up (p = 0.105). Scores worsened from preoperative assessment to last follow-up assessment in five of eight (62.5%) patients completing both pre- and postoperative surveys. Discussion: Herein, we report a large series (n = 16) of ASB meningiomas treated using endoscopic endonasal techniques. Our findings add to the growing body of evidence suggesting that these approaches produce comparable resections to open surgery. Gross total resection was achieved in 68.75% of patients, with all patients presenting with visual loss reporting improvements at follow-up. We further demonstrate that routine lumbar drainage can produce low CSF leak results. Finally, we describe the first series of SNOT-22 outcomes in strictly ASB meningiomas treated endoscopically and establish a baseline for further studies of sinonasal outcomes.

The Authors report a case of meningioma with implant base in the right posterior clinoid process (PCP) successfully treated through a fronto-temporo-orbito-zygomatic (FTOZ) approach. As the authors claim, the definition of PCP meningiomas refers to lesions eccentrically originating at the level of dorsum sellae; this precisation is important because it implies surgical strategies different from the ones requested for centrally located lesions, which are the true dorsum sellae meningiomas (also defined upper clival);[1] also clinical symptomatology appears different for dorsal parasellar lesions with central or lateral implant: Central ones growth superiorly to occupy the interpeduncular cistern and the third ventricle room compressing the chiasm from posterior, while meningiomas with lateral implant on PCP compress the optic pathways from lateral. The rarity of meningiomas arising from PCP makes it impossible to systematize the possible approaches; however, in this paper the approaches used from other cases in the literature are critically reviewed and the rationale for the choice of the FTOZ craniotomy combined with silvian fissure opening is very well discussed; the FTOZ approach effectively appears the most useful one when dealing with this kind of tumors, because it allows the better dissection from perforators coming from the posterior wall of the internal carotid artery (ICA) working in the corridor between the artery and the tentorial edge rather than in the optico-carotid corridor (it is noteworthy that the lateral corridor may be further enlarged by sectioning the most proximal portion of the edge of the tentorial notch). In my opinion the use of endoscopic assistance to microsurgery (EAM) may be extremely helpful in the treatment of these lesions, deeply located in a limited arachnoidal space where critical neurovascular structures are embedded;[2] EAM may allow a better lesional control and dissection and may even allow less invasive approaches; we have reported this technique for the treatment of intracranial lesions,[3] also describing a case, similar to the one presented in this article, in which the use of the endoscope allowed the resection of the lesion through a pterional approach [Figures ​[Figures11 and ​and22]. Figure 1 Preoperative (a, b) and postoperative (c, d) axial and sagittal T1 gadolinium enhanced MR scans of the lesion Figure 2 Microsurgical view of the internal carotid artery (ICA) and tumor (Tu), the 0°-scope (Scope) was initially introduced free hand to expose the 3rd cranial nerve (3cn) located in the depth of the operative field (a). The 3rd cranial nerve was thereafter ...

Purpose Vascular complications induced by intercavernous sinus injury during dural opening in the transsphenoidal surgery may contribute to incomplete tumour resections. Preoperative neuro-imaging is of crucial importance in planning surgical approach. The aim of this study is to correlate the microanatomy of intercavernous sinuses with its contrast-enhanced magnetic resonance venography (CE-MRV). Methods Eighteen human adult cadavers and 24 patients were examined based on autopsy and CE-MRV. Through dissection of the cadavers and CE-MRV, the location, shape, number, diameter and type of intercavernous sinuses were measured and compared. Results Different intercavernous sinuses were identified by their location and shape in all the cadavers and CE-MRV. Compared to the cadavers, CE-MRV revealed 37% of the anterior intercavernous sinus, 48% of the inferior intercavernous sinus, 30% of the posterior intercavernous sinus, 30% of the dorsum sellae sinus and 100% of the basilar sinus. The smaller intercavernous sinuses were not seen in the neuro-images. According to the presence of the anterior and inferior intercavernous sinus, four types of the intercavernous sinuses were identified in cadavers and CE-MRV, and the corresponding operative space in the transsphenoidal surgical approach was implemented. Conclusion The morphology and classification of the cavernous sinus can be identified by CE-MRV, especially for the larger vessels, which cause bleeding more easily. Therefore, CE-MRV provides a reliable measure for individualized preoperative planning during transsphenoidal surgery.

BackgroundSeveral groups of stem cryptodires became adapted to coastal marine environments as early as the Late Jurassic, 40 million years before the Pan-Chelonioidea. The Plesiochelyidae are a major component of this first radiation of crown-group turtles into marine habitats. They are abundant in many European localities, but their systematics is still greatly confused. Only three species are represented by cranial material: Plesiochelys etalloni, Plesiochelys planiceps, and Portlandemys mcdowelli.Methodology/principal findingsIn the present study, we describe a cranium and a mandible from the Kimmeridgian of Porrentruy (Switzerland), which we refer to a new species, Portlandemys gracilis n. sp. This new taxon differs from Portlandemys mcdowelli in several aspects of the cranium and mandible, notably in being generally more gracile, but the two species share a narrow skull, a more acute angle between the labial ridges on the mandible, and a unique configuration of the anterodorsal part of the basicranium. The cranial anatomy of plesiochelyid turtles is discussed in details based primarily on these new specimens and new cranial material of Plesiochelys etalloni from Solothurn, Switzerland.Conclusions/significanceSeveral characters (e.g., the contribution of the parietal to the foramen nervi trigemini, the configuration of the dorsum sellae and sella turcica, the presence of an infolding ridge on the posterior surface of the quadrate) appear as potential candidates to help elucidate plesiochelyid relationships. Some of these characters are included in a previously published phylogenetic dataset and help to stabilize the relationships of plesiochelyid turtles and closely related taxa. For the first time, our results suggest that plesiochelyids, 'Thalassemys' moseri, and Solnhofia parsonsi (representing the Eurysternidae) form a clade at the base of Eucryptodira.

Meningiomas represent the most common primary intracranial neoplasm treated by neurosurgeons. Although multimodal treatment of meningiomas includes surgery, radiation-based treatments, and occasionally medical therapy, surgery remains the mainstay of treatment for most symptomatic meningiomas. Because of the intricate relationship of the dura mater and arachnoid mater with the central nervous system and cranial nerves, meningiomas can arise anywhere along the skull base or convexities, and occasionally even within the ventricular system, thereby mandating a catalog of surgical approaches that neurosurgeons may employ to individualize treatment for patients. Skull base meningiomas represent some of the most challenging pathology encountered by neurosurgeons, on account of their depth, invasion, vascularity, texture/consistency, and their relationship to bony anatomy, cranial nerves, and blood vessels. Resection of complex skull base meningiomas often mandates adequate bony removal to achieve sufficient exposure of the tumor and surrounding region, in order to minimize brain retraction and optimally identify, protect, control, and manipulate sensitive neurovascular structures. A variety of traditional skull base approaches has evolved to address complex skull base tumors, of which meningiomas are considered the paragon in terms of both complexity and frequency.In this supplemental video issue of Neurosurgical Focus, contributing authors from around the world provide instructional narratives demonstrating resection of a variety of skull base meningiomas arising from traditionally challenging origins, including the clinoid processes, tuberculum sellae, dorsum sellae, petroclival region, falco-tentorial region, cerebellopontine angle, and foramen magnum. In addition, two cases of extended endoscopic endonasal approaches for tuberculum sellae and dorsum sellae meningiomas are presented, representing the latest evolution in accessing the skull base for selected tumors. Along with key pearls for safe tumor resection, an equally important component of open and endoscopic skull base operations for meningiomas addressed by the contributing authors is the reconstruction aspect, which must be performed meticulously to prevent delayed cerebrospinal fluid leakage and/or infections. This curated assortment of instructional videos represents the authors’ optimal treatment paradigms pertaining to the selection of approach, setup, exposure, and principles to guide tumor resection for a wide spectrum of complex meningiomas.

Purpose In order to numerically compare the morphological differences of the nasal cavity and nasal sinus between acromegalics and non-acromegalics, bone window CT scans sliced parallel to the transsphenoidal surgical route were performed. MATERIAL AND CASES: Acromegalic patients had small or large macroadenomas and were 13 (7 men and 6 women) in number, aged 53.2 +/- 16.1 years. Non-acromegalic patients had pituitary tumors and were 44 (21 men and 23 women) in number, aged 52.1 +/- 12.5 years. Results The results of acromegalics are described in comparison to non-acromegalics in parentheses. a) The width of the surgical corridor: piriform aperture, 27.6 +/- 2.7 (25.9 +/- 2.6) mm; origin of inferior nasal concha, 29.4 +/- 9.4 (26.6 +/- 4.0) mm; and origin of middle nasal concha, 29.8 +/- 3.2 (26.2 +/- 4.2) mm. b) The depth of the surgical corridor: the upper lip thickness, 18.1 +/- 2.7 (13.3 +/- 1.4) mm; the distances between piriform aperture and sphenoid wall, 52.9 +/- 4.6 (49 +/- 4.2) mm; sphenoid wall and sellar floor, 17.3 +/- 4.1 (18.7 +/- 4.1) mm; and sellar floor to dorsum sellae, 17.6 +/- 3.4 (15.6 +/- 4.0) mm. c) Marked carotid prominence: 7/13=53.4% (8/44=18.25%). d) Sinusitis: 8/13=61.5% (12/44=27.3%). Discussion & conclusion The data presented above show that morphological differences in bony nasal cavity and soft tissue may be responsible for a deeper and narrower surgical field for acromegalics. Acromegalics had a marked carotid prominence more frequently, which needs special attention to avoid carotid injury, when enlarging the surgical field. Knowing these morphological differences will provide useful information for peri- and intra-operative care.