Posterior Clinoid Research Articles

Surgical anatomy of the inferior hypophyseal artery and its relevance for endoscopic endonasal skull base surgery.

The inferior hypophyseal arteries (IHAs) are intimately related to pituitary and cavernous sinus (CS) lesions. There is still no anatomical study specifically analyzing the IHAs. The aim of this study was to investigate the surgical anatomy and variations of the IHA, and to translate this knowledge into surgical practice. Twenty anatomical specimens with vascular injection were used for endoscopic and transcranial dissection. The origin, arrangement patterns of the meningeal hypophyseal trunk (MHT), segmentation, trajectory, branching pattern in each segment, and dominance of the IHAs were investigated. The IHA was identified in all 40 sides (100%). The IHA originated from the MHT in 37 sides (92.5%) and directly from the cavernous internal carotid artery in 3 sides (7.5%). According to the relationship of the IHA with the MHT, dorsal meningeal artery (DMA), and tentorial artery (TA), the authors classified five patterns of IHA origin: type A (common trunk) was found in 16 sides (40%), type B (IHA-DMA branch trunk) was found in 8 sides (20%), type C (IHA-DMA stem trunk) was found in 7 sides (17.5%), type D (IHA-TA trunk) was found in 6 sides (15%), and type E (independent type) was found in 3 sides (7.5%). All IHAs could be divided into proximal (cavernous) and distal (glandular) segments. Four branching patterns of the proximal segment were observed: 0 branches (12.5%), 1 branch (42.5%), 2 branches (40%), and 3 branches (5%). Three patterns of the distal IHA were noticed: 1) single (25%), 2) bifurcation (65%), and 3) trifurcation (10%). The IHAs entered the posterior third of the medial wall of the CS in 75%, intermediate third in 17.5%, and anterior third in 7.5%. The proximal IHA ran in close relation with the lower third of the posterior clinoid process (PCP) in 80%, middle third in 15%, and upper third in 5%. The IHA can be divided into proximal and distal segments. Its proximal segment is most often found crossing the CS at the level of the lower third of the PCP and entering the posterior third of the medial wall of the CS. A detailed understanding of the surgical anatomy of the IHA and its variability will help surgeons dealing with challenging lesions within the CS and when performing transcavernous approaches, interdural posterior clinoidectomies, and pituitary gland transpositions.

Anatomy of Inferior Temporal Arteries in Relation to Middle Cranial Fossa Structures: A Postmortem Computed Tomography Angiography Study

Abstract Objective The inferior temporal arteries (ITAs), branches of the posterior cerebral artery (PCA), are critical vascular structures encountered during subtemporal surgical approaches. Anatomical data based on multiphase postmortem computed tomography angiography (MPMCTA) are provided as a tool for preoperative surgical planning to lower the risk of ITA injury. Methods Adult (≥18 years) cases that underwent MPMCTA during 2015 to 2023 and whose cause of death did not involve the cerebral circulation were included in the study. Standardized measurements on four predefined coronal slices in relation to the posterior clinoid process (PCP) were established with references to projections in axial and sagittal planes. The main aim was to assess the presence, width, and course of anterior ITA (AITA), middle ITA (MITA), and posterior (PITA) particularly within the individual established quadrants of the middle cranial fossa. Results A total of 74 hemispheres were studied among 37 patients with the mean age of 52 ± 20.2 years. PITA was present in 98.7% of studied hemispheres, followed by MITA in 90.7% and AITA in 89.2%. The course of PITA was straight (65.8%) or oblique (34.3%), with significant difference in mean width (p = 0.050), branching angle (p < 0.001), distance to tentorial hiatus (p < 0.001), and superior petrosal sinus (p < 0.001). A pattern of PITA loop was defined as a twisting of its course within the collateral sulcus. Significant relationship between the presence of AITA and MITA (p < 0.001) along with the co-presence of AITA and PITA (p = 0.029) was found. Conclusion Knowledge of ITA characteristics and their relationship to surrounding anatomical structures is vital in subtemporal neurosurgical interventions. Preoperative inspection of the collateral sulcus and its relation to the surgical trajectory is critical to prevent PITA injury.

9375 Acth-Producing Pituitary Carcinoma in the Falx Cerebri and Other Unusual Locations

Abstract Disclosure: J.E. Esquivel Vargas: None. A. Cob Guillén: None. A.B. Santos Rojo: None. A. Hong Lo: None. ACTH-producing Pituitary Carcinoma in the Falx Cerebri and other unusual locations Background: Pituitary carcinoma is a condition defined by metastasis of a pituitary tumor to a distant location. Pituitary carcinomas are very rare and account for approximately 0.12% of adenohypophyseal tumors (1). Clinical case: We present a case of a 29-year-old female who was followed up in our Endocrinology Department. Past medical history included the diagnosis of Cushing Disease and transsphenoidal tumor resection at 12 years of age, followed by transcranial resection two years later because of persistently elevated adrenocorticotropic hormone (ACTH). Despite the surgical management, the patient persisted with increased ACTH and hypercortisolism, so bilateral adrenalectomy was performed a year later. Two years after the procedure, the patient presented with a newly diagnosed pituitary macroadenoma, so the diagnosis of Nelson Syndrome was made. Linear accelerator radiotherapy was given, which reduced the size of the tumor. Later, multiple imaging studies showed multiple lesions on the falx cerebri, posterior clinoid process, retroclival region, cerebellopontine angle, pterygopalatine fossa, infratentorial region, and posterior ethmoidal cells. Biopsy and immunohistochemistry of the falx cerebri lesions described ACTH-producing pituitary adenocarcinoma. Treatment was given with intramuscular octreotide, dabrafenib, and trametinib. Despite persistently elevated ACTH levels, the patient has since remained clinically stable, without new development or worsening of symptoms. Conclusion: There are 3 unique aspects of our case. First, we reported an unusual presentation of this disease, because the patient in our case was a female with an early age of onset, in contrast with the reported literature. Second, this is the first reported case demonstrating pituitary carcinoma in the falx cerebri. Third, the prognosis of pituitary carcinoma is very poor, and mortality is extremely high, however, the patient in our case has been followed up for 7 years since the diagnosis of the metastatic lesions and has remained clinically stable.

Precise Localization of the Posterior Clinoid Process in the Fetal Skull Base.

To determine the precise position of the posterior clinoid process (PCP) in fetuses. Skull bases of 32 fetuses (11 males/21 females) aged 17 to 32 weeks in utero were included in the study. The distances of PCP to certain reference points were measured. The distances of PCP to the foramen ovale, foramen rotundum, superior orbital fissure, anterior clinoid process, foramen magnum, and crista galli were measured as 7.70±1.86mm, 6.99±1.65mm, 6.07±1.85mm, 3.85±1.10mm, 15.34±3.38mm, and 14.49±2.65mm, respectively. All parameters were similar for both sides (P>0.05). Apart from the distance of PCP to the foramen magnum, the remaining parameters were similar for both genders. This parameter was greater in males than females (P=0.001). All parameters were greater in the third-trimester fetuses than the second-trimester fetuses. All parameters increased with advancing gestational weeks (P<0.001). Linear functions were calculated for the distances of PCP to the crista galli (y = 1.311 + 0.551 × age), to the foramen magnum (y = 0.086 + 0.638 × age), to the anterior clinoid process (y = -0.303 + 0.174 × age), to the superior orbital fissure (y = - 2.013 + 0.338 × age), to the foramen rotundum (y = 1.803 + 0.217 × age), and to the foramen ovale (y = 0.760 + 0.290 × age). The measured distances increased with growth. The linear functions displaying the growth dynamics of PCP-related parameters may be used to estimate the distances.

Extended transcavernous posterior clinoidectomy in endoscopic endonasal surgery.

Mastery of the posterior clinoidectomy technique is of utmost importance for neurosurgeons who specialize in endoscopic endonasal approaches, because the posterior clinoid process (PCP) is commonly involved in chondroid tumor resection. Three main techniques for posterior clinoidectomy have been developed: intradural, extradural, and transcavernous interdural. The authors introduce here a novel technical variant in which the transcavernous approach is extended to the dorsal clinoidal space after transection of the caroticoclinoid ligament, and they elaborate on its clinical application on the basis of anatomical dissections and radiological studies. The authors reviewed CT angiography images and 3D reconstruction of the PCP in 50 adults to analyze the height and presence of ossified ligament attachments. In addition, endoscopic endonasal posterior clinoidectomy was performed in 20 lightly embalmed postmortem human heads. Three techniques, including extradural, transcavernous, and extended transcavernous posterior clinoidectomy, were performed sequentially, and anatomical landmarks and areas exposed with each technique were investigated and compared. Using radiological studies, the authors categorized the PCPs as 1 of 2 types: 1) normal, defined as less than or equal to 8 mm high with no ossified ligament attachments; or 2) complex, defined as greater than 8 mm high with or without an ossified ligament attachment. Compared with extradural (exposed PCP height 4.7 ± 0.5 mm) and transcavernous (exposed PCP height 7.3 ± 0.8 mm) posterior clinoidectomies, the extended transcavernous posterior clinoidectomy provided the maximally exposed PCP height (9.6 ± 0.4 mm; p < 0.0001). This report details the extended transcavernous posterior clinoidectomy as a novel technical variant for achieving maximal exposure of the PCP in endoscopic endonasal surgery. In addition, the positive results establish the importance of preoperative skull base imaging for surgical planning.

Zygomatic Anterolateral Temporal Approach for P1/P2 segment complex posterior cerebral aneurysm: a single-center retrospective study.

Treating complex posterior cerebral artery (PCA) aneurysms, such as fusiform, giant, and dissecting aneurysms, poses significant challenges. Parent artery occlusion carries a risk of ischemic stroke and fails to alleviate mass effects. This study aims to analyze the technical nuances and patient outcomes of treating complex PCA aneurysms, ranging from the P1 to P2P segments, using a Zygomatic Anterolateral Temporal Approach(ZATA) combined with flow reconstruction. This study was a retrospective study. Surgical treatment was performed on twelve patients with complex PCA aneurysms located in the P1 to P2P segments. Ten patients underwent flow reconstruction including Superficial Temporal Artery(STA)-Middle Cerebral Artery(MCA),Internal Maxillary Artery(IMA)-Radial Artery(RA)-MCA,STA-PCA(P2), and IMA-RA-PCA(P2). The aneurysm occlusion rate, surgical complications, and patient prognosis, including stroke occurrence/ modified Rankin Scale(mRS), were recorded and analyzed. Using the ZATA, all twelve complex PCA aneurysms were successfully clipped/resected/trapped. This included two high-position aneurysms (> 3mm above the posterior clinoid process) at the P1/P2 junction and three P2P aneurysms. The mass effects of six large or giant aneurysms were resolved or alleviated. Postoperative and follow-up CTA/DSA confirmed the patency of the bypass vessels. Four patients experienced strokes in the perioperative period, with three ischemic and one hemorrhagic. The median follow-up period was 28.5months. At the last follow-up, the good prognosis rate (mRS ≤ 2) was 83.3%, and one patient had died. Clipping/resection/trapping of aneurysms via the ZATA, combined with flow reconstruction, is a feasible option for treating complex PCA aneurysms from the P1 to P2P segments. This approach helps maintain or improve cerebral perfusion in the affected vascular territory.

The impact of spheno-occipital synchondrosis exposure via extended endoscopic endonasal surgery on midface growth in pediatric patients.

Pediatric extended endonasal procedures pose significant surgical challenges. Lesions from the suprasellar region to the lower clivus necessitate extensive exposure. This study examined whether drilling the spheno-occipital synchondrosis (SOS) to remove the posterior clinoid process and dorsum sellae (DS) for greater exposure affects pediatric midfacial growth. From 2014 to 2020, the authors performed endoscopic endonasal surgery (EES) in 14 patients aged 12 years or younger. The lesions consisted of 11 cases of craniopharyngioma, 1 pituitary neuroendocrine tumor, 1 Rathke's cleft cyst, and 1 Langerhans cell histiocytosis. In 8 of the 14 cases, an extended EES procedure was used by exposing the SOS to remove the posterior clinoid process and DS. Measurement of the central face was based on head MRI before and after surgery. Measuring points were the sellae-nasion (SN) plane, the foremost points of the anterior maxilla (point A), and the maximum concavity point of the mandibular symphysis (point B). The authors measured and evaluated the SNA angle (angle created by the SN plane and the NA [a line connecting point A and the nasion] plane), SNB angle (angle created by the SN plane and the NB [a line connecting point B and the nasion] plane), and the ANB angle (angle created by the NA plane and the NB plane). In addition, a comparison was made with 6 pediatric cases in which transcranial surgery was performed for craniopharyngiomas. In the extended EES group, the average preoperative age was 7 years, and the average postoperative age was 12 years. Mean preoperative angles in this group were 84° (SNA), 80.9° (SNB), and 3.1° (ANB); mean postoperative angles were 83.5° (SNA), 83.9° (SNB), and -0.4° (ANB). In the standard EES group, the average preoperative age was 9 years, and the average postoperative age was 14.5 years. Average preoperative angles in the standard EES group were 83° (SNA), 80.3° (SNB), and 2.7° (ANB); average postoperative angles were 82.7° (SNA), 81° (SNB), and 1.6° (ANB). In the transcranial surgery group, the average preoperative age was 4.5 years, and the average postoperative age was 9.8 years. Mean preoperative angles were 83.8° (SNA), 80.3° (SNB), and 3° (ANB); mean postoperative angles were 83.8° (SNA), 82.6° (SNB), and 1.2° (ANB). The only significant difference between groups was the postoperative ANB angle, which was negative in the extended EES group compared to the standard EES group, indicating the maxilla was positioned posteriorly compared to the mandible. The measurement values of the EES groups and the transcranial surgery group exhibited minimal differences, except for a significant decrease in the postoperative ANB angle in the extended EES group compared with the standard EES group. These results show that extended EES may impact midface growth. Further research is required to understand the long-term impact of SOS exposure.

Posterior clinoid process in children: morphometric analysis, pneumatization ratio, and surgical implications.

To describe pneumatization and topographic position of the posterior clinoid process (PCP) in healthy children when approaching the anterior and middle fossae. The study consisted of computed tomography images of 180 pediatric patients (90 males / 90 females), aged 1-18years. The presence or absence of PCP pneumatization was noted, and the distances of certain landmarks to PCP were measured. The distances of the foramen ovale, foramen rotundum, superior orbital fissure, anterior clinoid process (ACP), foramen magnum and crista galli to PCP were measured as 18.59 ± 3.36mm, 15.37 ± 3.45mm, 14.60 ± 3.05mm, 5.27 ± 3.24mm, 32.03 ± 3.27mm, and 30.45 ± 3.93mm, respectively. These parameters increased with growth (between 1-18years), but the distance between PCP and ACP decreased with an irregular pattern. In 11 sides (3.10%), a fusion between PCP and ACP was determined. PCP pneumatization was identified in 32 sides (8.9%). Its pneumatization correlated with pediatric ages (p < 0.001), but not gender (p = 0.459) or side (p = 0.711). Most of PCP pneumatization appeared after late childhood period (i.e., between 10-18years). Our study provides beneficial data for neurosurgeons to use PCP as a reference point for creating a skull base map in children, because of the incomparable position of PCP in the skull base center.

The Coexistence of Carotico-Clinoid Foramen and Interclinoidal Osseous Bridge: An Anatomo-Radiological Study With Surgical Implications.

The coexistence of complete carotico-clinoid bridge (CCB), an ossification between the anterior (ACP) and the middle clinoid (MCP), and an interclinoidal osseous bridge (ICB), between the ACP and the posterior clinoid (PCP), represents an uncommonly reported anatomic variant. If not adequately recognized, osseous bridges may complicate open or endoscopic surgery, along with the pneumatization of the ACP, especially when performing anterior or middle clinoidectomies. According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews guidelines, a systematic scoping review was conducted up to June 5, 2023. PubMed, Scopus, Web of Science databases, and additional citations were searched. Two hundred high-resolution noncontrast computed tomography (CT) scans (400 sides) and 41 dry skulls (82 sides) were analyzed to identify the different morphology of sellar bridges, focusing on the coexistence of complete CCF and ICB. Two embalmed latex-injected heads with coexisting CCF and ICB were dissected step-by-step to show the anatomic relationship with the surrounding structures from an endoscopic and microscopic perspective. A total of 19 articles were included. The review identified a complete CCF and ICB rate ranging from 4.92% to 6.3%. The analysis of 200 CT scans revealed a rate of coexistence in 4% of the cases, all encountered in White women. Two different types of interclinoid bridges were identified based on the degree of bone mineralization. Both endoscopic and macroscopic step-by-step dissections highlighted variability in morphology and consistency of the sellar bridges and the close relationship with the cavernous sinus neurovascular structures. The coexistence of CCF and ICB is an anatomic variation found in 4% of cases. Preoperative knowledge of the degree of mineralization and its relationship with surrounding structures is essential to performing safe surgery and minimizing cranial nerve and vascular injuries. Preoperative high-resolution CT scans can adequately identify these anatomic variations.

Morphology of the Sella Turcica in Individuals With Different Skeletal Malocclusions in Upper Egypt Assessed Using Lateral Cephalometric Radiographs.

To evaluate the morphology of sella turcica (ST) in individuals with different skeletal malocclusions in upper Egypt. 300 lateral cephalometric radiographs of adult patients of both sexes, varying ages from 18 to 30 years, were selected and divided into three equal groups, group (1): skeletal class I (control group), group (2): skeletal class II, and group (3): skeletal class III. Pre-treatment lateral cephalograms were taken from the archives of the Department of Orthodontics, Faculty of Dentistry, Minia University. The tuberculum and dorsum sella, the floor of ST, and posterior and anterior clinoid processes (ACPs) were drawn. The direct measurements such asdiameter (APD), depth (D), and length(L) of sella were measured using Silverman and Kisling methods. A significant difference was found in depth (D) between class I and class II, with class II having a greater depth.Also, the largest diameter (APD) was found in the class III group.A significant difference was found in diameter (APD) between the two age groups (from 18 to 24 years and from 25 to 30 years) Conclusion: The larger diameter values were seen in the skeletal class III subjects, while the larger depth values were observed in the class II subjects. The older age group (25-30 years) has a greater diameter than the younger one. Highly significant differences were found in length and depth between the sexes.

Morphometric Analysis of the Sella Turcica on Cone-Beam Computed Tomography Images.

Sella turcica is an important anatomic formation that contains the pituitary gland and is in a close neighborhood with many vital structures. It is important to know the morphometry of the sella turcica, as it is a transition point during surgical interventions such as the endoscopic endonasal transsphenoidal approach to the region. The findings obtained are thought to be useful in the examination of sella turcica and surrounding structures and will contribute to the literature by knowing the morphometry of the region for the surgical method. In this study, cone-beam computed tomography images of 400 individuals, 200 females and 200 males, aged between 18 and 65 years, who did not have craniofacial pathology, who applied to Gaziantep University, Faculty of Dentistry between 2015 and 2020 for any reason, were evaluated retrospectively. In the sagittal section, 8 parameters were examined, 6 of which were transverse. The length () of the sella turcica in the sagittal plane is 10.19±1.77mm, the diameter of the sella turcica is 11.6±1.69mm, the anterior height of the sella turcica is 7.88±1.56mm, the median height of the sella turcica 8.18±1.42mm, posterior height of sella turcica 6.98±1.31mm, width of sella turcica 11.10±1.6mm. The distance between anterior clinoid processes in the transverse plane was 24.93±2.57mm, and the distance between posterior clinoid processes was 14.92±2.46mm. It was determined that there was an increase in many parameters with age, and length of the sella turcica and anterior clinoid processes were statistically significantly higher in males.

Microanatomical Investigation of the Subtemporal Transtentorial Approach

To study the microanatomic structure of the subtemporal transtentorial approach to the lateral side of the brainstem, and to provide anatomical information that will assist clinicians to perform surgeries on the lateral, circumferential, and petroclival regions of the brainstem. Anatomical investigations were conducted on 8 cadaveric head specimens (16 sides) using the infratemporal transtentorial approach. The heads were tilted to one side, with the zygomatic arch at its highest point. Then, a horseshoe incision was made above the auricle. The incision extended from the midpoint of the zygomatic arch to one third of the mesolateral length of the transverse sinus, with the flap turned towards the temporal part. After removing the bone, the arachnoid and the soft meninges were carefully stripped under the microscope. The exposure range of the surgical approach was observed and the positional relationships of relevant nerves and blood vessels in the approach were clarified. Important structures were photographed and the relevant parameters were measured. The upper edge of the zygomatic arch root could be used to accurately locate the base of the middle cranial fossa. The average distances of the star point to the apex of mastoid, the star point to the superior ridge of external auditory canal, the anterior angle of parietomastoid suture to the superior ridge of external auditory canal, and the anterior angle of parietomastoid suture to the star point of the 10 adult skull specimens were 47.23 mm, 45.27 mm, 26.16 mm, and 23.08 mm, respectively. The subtemporal approach could fully expose the area from as high as the posterior clinoid process to as low as the petrous ridge and the arcuate protuberance after cutting through the cerebellar tentorium. The approach makes it possible to handle lesions on the ventral or lateral sides of the middle clivus, the cistern ambiens, the midbrain, midbrain, and pons. In addition, the approach can significantly expand the exposure area of the upper part of the tentorium cerebelli through cheekbone excision and expand the exposure range of the lower part of the tentorium cerebelli through rock bone grinding technology. The total length of the trochlear nerve, distance of the trochlear nerve to the tentorial edge of cerebellum, length of its shape in the tentorial mezzanine, and its lower part of entering into the tentorium cerebelli to the petrosal ridge were (16.95±4.74) mm, (1.27±0.73) mm, (5.72±1.37) mm, and (4.51±0.39) mm, respectively. The cerebellar tentorium could be safely opened through the posterior clinoid process or arcuate protrusion for localization. The oculomotor nerve could serve as an anatomical landmark to locate the posterior cerebral artery and superior cerebellar artery. Through microanatomic investigation, the exposure range and intraoperative difficulties of the infratemporal transtentorial approach can be clarified, which facilitates clinicians to accurately and safely plan surgical methods and reduce surgical complications.

Multiple coexisting variations of skull and cervical spine anatomy in a symptomatic patient - uncommon or uncommonly noticed? A CT-based case study.

Among many anatomical variations of the skull and cervical spine, some may be an underlying cause of a disease, while others remain clinically silent. The estimated individual prevalences of them differ, but given the available data it is impossible to clarify how frequently they coexist with each other. The following study presents an example of seven anomalies, amongst which at least few have manifested clinically in the examined patient. A 35 y.o. Polish woman who suffered from chronic sinusitis was subjected to a computed tomography scan. Mild thickening of the anterior ethmoidal cells' mucosa, bilateral concha bullosa, paradoxical right middle turbinate, bilateral uncinate process pneumatization and arrested pneumatization of sphenoid sinus were found and addressed in context of the reported symptoms. Simultaneously other, clinically silent anatomical anomalies, were found - namely ossification of the anterior petroclinoid ligament, incomplete medial basal canal and bilateral arcuate foramen. To the best knowledge of the authors, this case report is the first to present such a coexistence of this many various anatomical anomalies, among which some played a crucial part in the chronic sinusitis experienced by the patient. Concurrence of multiple variations in the same anatomical area or functional unit may exacerbate clinical presentation of a patient. Identifying a single anomaly ought to warrant a thorough investigation into any other potentially existing variants.

Topographic Anatomy and Pneumatization of the Posterior Clinoid Process in Chiari Type I Malformation

ObjectiveThis study aimed to examine pneumatization and topographic location of the posterior clinoid process (PCP) in Chiari type I malformation (CIM) for skull base approaches. MethodsComputed tomography images of 52 (23 males / 29 females) CIM subjects aged 23.87±16.09 years, and 71 (26 males / 45 females) healthy subjects aged 42.48±21.48 years constituted the study universe. ResultsThe distances of PCP to the foramen magnum (p=0.037), superior orbital fissure (p<0.001), foramen rotundum (p<0.001), and foramen ovale (p<0.001) were smaller, but the distance of PCP to the crista galli (p=0.038) was greater in CIM patients, compared to normal subjects. In CIM, the fusion between PCP and the anterior clinoid process was observed in nine sides (8.70%), while in controls, in 12 sides (8.50%). PCP pneumatization was observed in 40 sides (38.50%) in CIM patients, while in 28 sides (19.70%) in normal subjects. This data displayed that PCP pneumatization was affected by CIM (p<0.001). ConclusionThe distances of PCP to the crista galli and foramen magnum indicate the anterior fossa length and the posterior fossa depth, respectively; thus, CIM patients have longer anterior fossa and shallow posterior fossa. In addition, the distances of PCP to superior orbital fissure, foramen rotundum and foramen ovale indicate the middle fossa width; thence, CIM patients have less middle fossa width than normal individuals. CIM patients have approximately 50% higher PCP pneumatization rate, and this may increase the risk of complications such as cerebrospinal fluid fistula during the application of posterior clinoidectomy.

Calcification patterns and morphology of Sella turcica are related to anteroposterior skeletal malocclusions: A cross-sectional study

BackgroundThe sphenoid bone is an irregular, unpaired, symmetrical bone located in the middle of the anterior skull and is involved in craniofacial growth and development. Since the morphology of Sella turcica (ST) is associated with different craniofacial patterns, this study aimed to investigate if there is a correlation between ST morphology on the one hand and sagittal craniofacial patterns on the other hand. MethodsThis study was conducted with a convenience sample that included Brazilian individuals undergoing orthodontic treatment. Lateral cephalograms were used to evaluate the calcification pattern and morphology of ST, as well as skeletal class by analyzing the ANB angle. Pearson's chi-square test with Bonferroni post-hoc test was performed to evaluate the association between ST calcification pattern and morphology, and anteroposterior skeletal malocclusion. The established significance level was 0.05. ResultsThe study collective was comprised of 305 orthodontic patients (178 (58.4 %) female, 127 (41.6 %) male), who had a mean age of 23.2 (±10.6) years. 131 participants (42.9 %) presented skeletal class I, 142 (46.6%) skeletal Class II, and 32 (10.5%) had a skeletal class III. The degree of prognathism of the mandible showed a homogenous distribution within the study collective (91 (29.9 %) orthognathic, 100 (32.9 %) retrognathic, 113 (37.2 %) prognathic mandible). Concerning the maxilla, 92 (30.2%) individuals presented an orthognathic upper jaw, whereas 60 (19.7%) showed maxillary retrognathism and 153 (50.2%) maxillary prognathism. Compared to patients with skeletal class I, skeletal class III individuals presented significantly more hypertrophic posterior clinoid process (p<0.007) and pyramidal shape of the dorsum of the ST (p<0.038). ConclusionsOur results suggest that the hypertrophic posterior clinoid process and pyramidal shape of the ST dorsum are more prevalent in individuals with skeletal class III malocclusion.

Exploring the association between PITX2, third molars agenesis and sella turcica morphology

ObjectivesPITX2 is required for mammalian development and single nucleotide polymorphisms (SNPs) in this gene could be involved in dental agenesis and sella turcica patterns. Thus, the present study evaluated the association between SNPs in PITX2, third molars agenesis and sella turcica phenotypes.Materials and methodsThe sample consisted of healthy orthodontic German patients with lateral cephalometric radiographs with clearly visualization of the sella turcica, and dental orthopantomograms. The morphological variations of the sella turcica were evaluated using the lateral cephalograms, while third molar agenesis was evaluated using orthopantomograms. DNA isolated from buccal cells was used for genotyping three SNPs in PITX2 (rs3796902, rs1947187, and rs2595110). The analyzes were performed using a significance of 5%. There was no association between third molar agenesis and sella turcica phenotypes (p > 0.05). SNPs in PITX2 were also not associated with third molars agenesis (p > 0.05).ResultsSNPs in PITX2 were associated with sella turcica phenotypes. The rs3796902 was associated with hypertrophic posterior clinoid process (p = 0.013). The rs1947187 and rs2595110 were associated with sella turcica bridge type A (p = 0.013 and p = 0.011, respectively for genotype distribution). Patients that carry the genotypes GG-CC-AG (rs3796902- rs1947187- rs2595110) had 7.2 higher chance to present sella turcica bridge type A (p = 0.002; Odds ratio = 7.2, Confidence interval 95% 2.04–27.04).ConclusionsThird molar agenesis was not associated with SNPs in PITX2 and sella turcica phenotypes. SNPs in PITX2 may have an important role in sella turcica pattern.

Evaluation of pneumatized structures and osteoma frequency in the paranasal region

Aims: The aim of our study was to evaluate the incidence of pneumatized structures in the paranasal region and the presence of osteomas. Methods: Paranasal CT images obtained with Multislice (Philips) 64-slice computed tomography (CT) at Kırıkkale University Hospital in 2023 were retrospectively analyzed. Pneumatized variations and the presence of osteoma were evaluated. Results: The images of 186 patients (93 female and 93 male) with paranasal CT were analyzed. The most common pneumatized variation was middle turbinate bullosa with 40.3%, and the least common was pneumatization of the nasal septum with 2.1%. Anterior clinoid pneumatization was observed in 23.1%, posterior clinoid pneumatization in 2.2%, pneumatization of the uncinate process in 4.9%, and crista galli pneumatization in 4.3%. The frequency of osteomas in the paranasal region was 3.2% (n=6). Conclusion: Our study will provide a better understanding of paranasal anatomy by providing information about the frequency of pneumatized paranasal variations and the presence of osteomas. This will guide the surgeon in surgical planning and at the time of surgery.

Retrosigmoid Intradural Suprameatal Approach: 2-Dimensional Operative Video

INDICATIONS: CORRIDOR AND LIMITS OF EXPOSURE: The retrosigmoid intradural suprameatal approach is mostly indicated for tumors in the cerebellopontine angle extending toward the Meckel cave and supratentorial regions, most frequently meningiomas and schwannomas. This approach was first established by the senior author in 1982. ANATOMIC ESSENTIALS: NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: Nervous structures: cranial nerves III to XII, cerebellum, and brainstem. Vascular structures: anterior inferior cerebellar artery, posterior inferior cerebellar artery, superior cerebellar artery, basilar artery, vertebral artery, transverse, sigmoid, and petrous sinus, petrosal vein/veins, basilar plexus, and the mastoid emissary vein. Bony structures: petrous bone with internal auditory canal, jugular foramen and suprameatal tubercle, petrous apex, dorsum sellae, and posterior clinoid process. Structures within the petrous bone: vestibule, semicircular canals, and jugular bulb. ESSENTIALS STEPS OF THE PROCEDURE: After a suboccipital retrosigmoid craniectomy in the semisitting position and debulking of the tumor mass in the cerebellopontine angle, extension is achieved by drilling suprameatal tubercle above cranial nerve VII and VIII toward the petrous apex. The extent of bone drilling is tailored for each patient. PITFALLS/AVOIDANCE OF COMPLICATIONS: Avoid damage to cranial nerves, arteries, and veins during drilling, dissection, and tumor removal or by retraction. VARIANTS AND INDICATIONS FOR THEIR USE: In case of extreme supratentorial extensions laterally and dorsally, the opening of the tentorium may be helpful. For inferior extensions toward the upper spinal canal, opening of the foramen magnum and hemilaminectomy of C1 may be necessary. The patient consented to the procedure and to the publication of his/her image. Institutional logo in title slide, © 2023, INI Hannover. Used with permission.

Petroclival Clinoidal Folds and Arachnoidal Membranes of the Anteromedial Incisural Space: Clinical Anatomy for Neuro Critical Care.

A systematic and narrative literature review was performed, focusing attention on the anatomy of the area located at the junction of the sphenoid and the basal portion of the temporal bone (petrous bone, petrous apex, upper petro-clival region) encircled by the free edge of the tentorium, the insertion of the tentorium itself to the petrous apex and the anterior and posterior clinoid processes that give rise to three distinct dural folds or ligaments: the anterior petroclinoid ligament, the posterior petroclinoid ligament and the interclinoid ligament. These dural folds constitute the posterior portion of the roof of the cavernous sinus denominated "the oculomotor triangle". The main purpose of this review study was to describe this anatomical region, particularly in the light of the relationships between the anterior margin of the free edge of the tentorium and the above-mentioned components of the sphenoid and petrous bone.

Pituitary adenoma with oculomotor cistern extension: membranous anatomy and clinical application.

The anatomical basis of pituitary adenomas (PAs) with oculomotor cistern (OC) extension as a growth corridor is overlooked in the literature. In this paper, the authors use the technique of epoxy sheet plastination to study the membranous structure of the OC and validate the results by retrospective analysis of patients with OC extension. Eighteen specimens were used to study the membranous anatomy surrounding the OC using the epoxy sheet plastination technique. Thirty-four patients with OC extension were retrospectively reviewed. The OC consisted of two thin membranous layers. The inner layer was extended by the arachnoid layer from the posterior fossa, and the lateral layer consisted of the dura mater sinking from the roof of the cavernous sinus. The oculomotor nerve is more likely to displace with a superolateral trajectory due to the weakness of the posterior dura and the relatively large space in the medial and posterior trajectories, which is consistent with the intraoperative observations. Among the anatomical factors that affect the PA by OC extension, we found that the relative position of the internal carotid artery (ICA) and posterior clinoid process may lead to the narrowing of the OC. Of 34 cases, 28 patients achieved total resection. Among 24 preoperative patients with oculomotor nerve palsy, 16 cases were relieved to varying degrees postoperatively. There was no ICA injury or severe intracranial infection found in any of the patients. Extension into the OC is influenced by two anatomical factors: a weak point in the dura in the posterior OC and a potential space beyond this region of the dura. Meticulous knowledge of the membranous anatomy in endoscopic endonasal surgery is required to safely and effectively resect PA with OC extension.