Angle Evaluation of Possible Routes that Can Be Used to Reach the Foramen Ovale in the Anterior Approach / Evaluación Angular de Posibles Rutas que se Pueden Utilizar para Alcanzar el Foramen Oval en el Abordaje Anterior

SUMMARY: For the treatment of trigeminal neuralgia, the foramen ovale is reached by entering the cheek with a needle. Thermocoagulation is performed with balloon compression, administration of alcohol or radiofrequency. Apart from the classical method, it is theoretically possible to reach the foramen ovale through the mouth with the anterior approach. In our study, it was aimed to examine horizontally and vertically the angular values that must be given to the needle to reach the foramen ovale in the anterior approach. Three landmark points were determined on both right and left sides of 25 dry skulls. A rod was inserted starting from these landmark points and passing through the center of the foramen ovale. The vertical and horizontal angular values of this bar were measured. For each foramen ovale, 3 vertical angles, 3 horizontal angles and 4 distance measurements were made. There was a significant difference between the right and left sides in terms of horizontal angular values. Average values of horizontal angles (in degrees); on the right, 7.29 for H1, 12.15 for H2, 32.29 for H3; 1.26 for H1, 9.46 for H2, and 30.56 for H3 on the left side (p<0.005). The angle value was measured as 0 or negative value in 5 (20 %) of the H1 angle measurements made on the right side and 14 (56 %) on the left side. The H2 angle value was found to be smaller than the H1 angle in the skull 2 (8 %) on the right and 3 (12 %) on the left. There was no difference between the right and left sides in terms of vertical angular values. A significant difference was found between the right and left sides in the D1, D2, D4 distances (p<0.005). Six important anatomical features affecting angular values were encountered.

Para el tratamiento de la neuralgia del trigémino, se alcanza el foramen oval introduciendo una aguja en la mejilla. La termocoagulación se realiza con compresión con balón, administración de alcohol o radiofrecuencia. Aparte del método clásico, en teoría es posible alcanzar el foramen oval a través de la cavidad oral mediante el abordaje anterior. En nuestro estudio se tuvo como objetivo examinar horizontal y verticalmente los valores angulares que se deben dar a la aguja para alcanzar el foramen oval en el abordaje anterior. Se determinaron tres puntos de referencia en los lados derecho e izquierdo de 25 cráneos secos. Se insertó una varilla comenzando desde estos puntos de referencia y pasando por el centro del foramen oval. Se midieron los valores angulares verticales y horizontales de esta barra. Para cada foramen oval se realizaron mediciones de 3 ángulos verticales, 3 ángulos horizontales y 4 distancias. Hubo una diferencia significativa entre los lados derecho e izquierdo en términos de valores angulares horizontales. Valores medios de ángulos horizontales (en grados); a la derecha, 7,29 para H1, 12,15 para H2, 32,29 para H3; 1,26 para H1, 9,46 para H2 y 30,56 para H3 en el lado izquierdo (p<0,005). El valor del ángulo se midió como 0 o valor negativo en 5 (20 %) de las mediciones del ángulo H1 realizadas en el lado derecho y 14 (56 %) en el lado izquierdo. Se encontró que el valor del ángulo H2 era menor que el ángulo H1 en el cráneo 2 (8 %) a la derecha y 3 (12 %) a la izquierda. No hubo diferencia entre los lados derecho e izquierdo en términos de valores angulares verticales. Se encontró diferencia significativa entre el lado derecho e izquierdo en las distancias D1, D2, D4 (p<0,005). Se encontraron seis características anatómicas importantes que afectan los valores angulares.

A Six-Surface System to Describe Anatomy of Anterior Clinoid Process and Its Application in Anterior Clinoidectomy and Resection of Paraclinoid Meningioma.

OBJECTIVE: The anterior clinoid process (ACP) is surrounded by nerves and vessels that, together, constitute an intricate anatomical structure with variations that challenges the performance of individualized anterior clinoidectomy in treating lesions with different extents of invasion. In the present study, we established a 6-surface system for the ACP based on anatomical landmarks and analyzed its value in guiding ACP drilling and resection of paraclinoid meningiomas. METHODS: Using the anatomical characteristics of 10 dry skull specimens, we set 9 anatomical landmarks to delineate the ACP into 6 surfaces. Guided by our 6-surface system and eggshell technique, 5 colored silicone-injected anatomical specimens were dissected via a frontotemporal craniotomy to perform anterior clinoidectomy. Next, 3 typical cases of paraclinoid meningioma were selected to determine the value of using our 6-surface system in tumor resection. RESULTS: Nine points (A-H and T) were proposed to delineate the ACP surface into frontal, temporal, optic nerve, internal carotid artery, cranial nerve III, and optic strut surfaces according to the adjacent tissues. Either intradurally or extradurally, the frontal and temporal surfaces could be identified and drilled into depth, followed by skeletonization of the optic nerve, cranial nerve III, internal carotid artery, and optic strut surfaces. After the residual bone was removed, the ACP was drilled off. In surgery of paraclinoid meningiomas, our 6-surface system provided great benefit in locating the dura, nerves, and vessels, thus, increasing the safety of opening the optic canal and relaxing the oculomotor or optic nerves and allowing for individualized ACP drilling for meningioma removal. CONCLUSIONS: Our 6-surface system adds much anatomical information to the classic Dolenc triangle and can help neurosurgeons, especially junior ones, to increase their understanding of the paraclinoid spatial structure and accomplish individualized surgical procedures with high safety and minimal invasiveness.

Crista Galli Morphometry and Morphology: An Anatomical, Radiological, and Machine Learning Application Study / Crista Galli Morfometría y Morfología: Un Estudio de Aplicación Anatómica, Radiológica y de Aprendizaje Automático

SUMMARY: The study purposed to examine the morphometry and morphology of crista galli in cone beam computed tomography (CBCT) and apply a new analysis, supervised Machine Learning techniques to find the answers to research questions "Can sex be determined with crista galli morphometric measurements?" or "How effective are the crista galli morphometric measurements in determining sex?". Crista galli dimensions including anteroposterior, superoinferior, and laterolateral were measured and carried out on 200 healthy adult subjects (98 females; 102 males) aged between 18-79 years. Also, crista galli was classified with two methods called morphological types and Keros classification. In this study, the Chi-square test, Student's t-test, and Oneway ANOVA were performed. Additionally, Machine Learning techniques were applied. The means of the CGH, CGW, and CGL were found as 14.96 mm; 3.96 mm, and 12.76 mm in males, respectively. The same values were as 13.54 mm; 3.51 mm and 11.59±1.61 mm in females, respectively. The CG morphometric measurements of males were higher than those of females. There was a significant difference between sexes in terms of morphological classification type. Also, when the sex assignment of JRip was analyzed, out of 102 male instances 62 of them were correctly predicted, and for 98 female instances, 70 of them were correctly predicted according to their CG measurements. The JRip found the following classification rule for the given dataset: "if CGH<=14.4 then sex is female, otherwise sex is male". The accuracy of this rule is not high, but it gives an idea about the relationship between CG measurements and sex. Although the issue that CG morphometric measurements can be used in sex determination is still controversial, it was concluded in the analysis that CG morphometric measurements can be used in sex determination. Also, Machine Learning Techniques give an idea about the relationship between CG measurements and sex.

En el estudio se propuso examinar la morfometría y la morfología de la crista galli del hueso etmoides usando tomografía computarizada de haz cónico (CBCT) y aplicar un nuevo análisis, técnicas de aprendizaje automático supervisado para encontrar las respuestas a las preguntas de investigación "¿Se puede determinar el sexo con mediciones morfométricas de la crista galli?" o "¿Qué tan efectivas son las medidas morfométricas de la crista galli para determinar el sexo?". Las dimensiones de la crista galli, incluidas los diámetros anteroposterior, superoinferior y laterolateral, se midieron y realizaron en 200 sujetos adultos sanos (98 mujeres; 102 hombres) con edades comprendidas entre los 18 y los 79 años. La crista galli se clasificó con dos métodos llamados tipos morfológicos y clasificación de Keros. En este estudio, se realizaron la prueba de Chicuadrado, la prueba t de Student y ANOVA de una vía. Adicionalmente, se aplicaron técnicas de Machine Learning. Las medias de CGH, CGW y CGL se encontraron en 14,96 mm; 3,96 mm y 12,76 mm en hombres, respectivamente. Los mismos valores fueron 13,54 mm; 3,51 mm y 11,59 ± 1,61 mm en mujeres, respectivamente. Las medidas morfométricas del CG de los hombress fueron más altas que las de las mujeres. Hubo una diferencia significativa entre sexos en cuanto al tipo de clasificación morfológica. Además, cuando se analizó la asignación de sexo de JRip, de 102 instancias masculinas, 62 de ellas se predijeron correctamente, y de 98 instancias femeninas, 70 de ellas se predijeron correctamente de acuerdo con las mediciones de CG. El JRip encontró la siguiente regla de clasificación para el conjunto de datos dado: "si CGH<=14.4, por tanto el sexo es femenino, de lo contrario, el sexo es masculino". La precisión de esta regla no es alta, pero da una idea de la relación entre las medidas del CG y el sexo. Aunque la pregunta si las medidas morfométricas CG se pueden usar en la determinación del sexo sigue aún siendo controvertida. Se concluyó en el análisis que las medidas morfométricas CG se pueden usar en la determinación del sexo. Además, las técnicas de aprendizaje automático dan una idea de la relación entre las medidas de CG y el sexo.

Morphological and Metrical Relationships Between Sphenoid Sinus and Sella Turcica: Possible Applications in Transnasal Transsphenoidal Surgery.

INTRODUCTION: Transsphenoidal surgeries imply the risk of intraoperative lesions to the neurovascular structures surrounding the sphenoid sinus (SS). Aim of the present study is to assess the metrical and morphologic relationships existing between SS and sella turcica (ST). MATERIALS AND METHODS: Two hundred computed tomography-scans of patients were selected. For each patient volumes of SS were calculated from their 3-dimensional models segmented through ITK-SNAP program. Variants of SS in pneumatisation and sellar diameters [antero-posterior (AP) diameter, depth, and length] were evaluated on each computed tomography-scan. Correlations among different measurements were assessed through Spearman test ( P <0.01), whereas associations between sellar parameters and presence of pneumatisation variants were assessed through Mann-Whitney test ( P <0.01). RESULTS: In males, pneumatization of the greater wings was related to smaller AP diameter ( P <0.01) and depth of ST ( P <0.01), whereas in females lower values of depth were found in patients with pneumatization of the pterygoid processes ( P <0.01). In both sexes, a positive correlation was found between AP diameter and, respectively, length and depth of ST ( P <0.01), together with a negative correlation between volume of SS and depth of ST ( P <0.01). Lastly, in females a positive correlation was found between age and, respectively, length and depth of ST ( P <0.01). CONCLUSIONS: The present study highlighted new metrical and morphologic relationships between volume and pneumatisation of SS and diameters of ST. Knowledge of these correlations allows to understand more clearly, in the preoperative setting, the surgical working space. Further studies are needed, especially for what concerns the relationship between sellar measurements and age in females.

Radiological examination of the relationship between the pterygomaxillary junction and fracture pattern.

BACKGROUND: Le Fort 1 (LF1) osteotomies are widely used to correct midface deformities. To move the maxilla freely, the ptery-gomaxillary junction (PMJ) must be separated. When performing this osteotomy, the pterygoid plate must remain intact. The objective of this study was to evaluate relationship between the anatomical features of the PMJ and fracture patterns in LF1 osteotomy. METHODS: Pre-operative and post-operative cone-beam computed tomography images of 41 patients (82 samples) who have undergone LF1 osteotomy surgery were radiologically evaluated. Morphologic measurements of the pterygomaxillary fissure area and pterygoid plate were carried out. Moreover, pterygomaxillary separation was divided into the clean-cut, maxillary sinus, and pterygoid plate fracture types. RESULTS: Statistically significant difference was observed between clean-type fracture and pterygoid plate fracture groups' thickness of the pterygoid process and thickness of the pterygomaxillary region. CONCLUSION: Anatomical variations make it difficult to separate the PMJ properly. Low thickness of PMJ increases the risk of unwanted fractures; however, according to our experience, the use of an osteotome with an incorrect angle, excessive force, and inexperienced surgeons can also cause undesirable pterygoid plate fractures.

Morphologic and Morphometric Measurements of the Foramen Ovale: Comparing Digitized Measurements Performed on Dried Human Crania With Computed Tomographic Imaging. An Observational Anatomic Study.

The foramen ovale (FO) of the sphenoid bone is clinically important for the interventional treatment of trigeminal neuralgia. Percutaneous procedures applied to treat the chronic pain condition typically involve the cannulation of this oval-like foramen located at the base of the skull. Anatomic variations of the FO have been reported to contribute to difficulties in the cannulation of this structure. Computed tomography (CT) can help the surgeon improve the accuracy and safety of the intervention. However, even with navigation technology, unsuccessful cannulation of the FO has been reported. The aim of this observational anatomic study was to define morphometric and morphologic data of the FO and to investigate for potential differences between measurements taken on dried human crania and digitized measurements of the FO measured on CT images. One hundred eighteen FOs were evaluated. Twenty FOs underwent CT scanning. The mean length of the foramen was 7.41±1.3 mm on the left side and 7.57±1.07 mm on the right. The mean width of the foramen was 4.63±0.86 mm on the left side and 4.33±0.99 on the right. The mean area on the left side was 27.11±7.58 and 25.73±6.64 mm 2 on the right. No significant left-right differences were found for any of these dimensions. The most important conclusion that we can draw is that the measurements can indeed be performed on CT images to obtain an accurate picture of the morphology. Considering the surgical importance of the FO and taking into consideration the limitations this study added to scientific knowledge, this study was constructive as far as neurosurgeons and anatomists are concerned.

[The significance of surgical anatomy in lateral orbital wall decompression]. / Znachenie khirurgicheskoi anatomii naruzhnoi stenki orbity.

The article reviews data on the anatomical and topographic features of the lateral wall in the context of performing orbital surgery and presents a description of the surgical areas of the lateral wall that are most important for increasing the volume of the orbit: the lacrimal keyhole, the sphenoid door jamb, and the basin of the inferior orbital fissure. Particular attention is given to the topographic anatomy of the sphenoid door jamb as the most promising area for orbital decompression and transorbital access to the skull base.

Endoscopic Endonasal Anterior Clinoidectomy: Volumetric Assessment and Feasibility.

BACKGROUND: Transcranial removal of the anterior clinoid process (ACP) provides access to the clinoidal segment of the internal carotid artery as well as superolateral decompression of the optic canal. Endoscopic endonasal approaches (EEAs) can access the entire medial and inferior portions of the optic canal, but no data exist to support what proportion of the anterior clinoid could be safely resected via an EEA. METHODS: A cadaveric anatomical study was performed with removal of the ACP in 3 major steps in order of difficulty and risk. At each step, the removal was stopped when no more bone of the ACP could be seen without traction on neural structures. After each step, a CT scan was performed to allow volumetric measurement of the remaining ACP. RESULTS: Twenty ACPs in 10 cadaveric heads were removed to various degrees using the described stepwise technique. The mean portion of the ACP resected by each step was 21%, 46%, and 27%, respectively. Cumulated ACP removal at the end of step 3 was 94%, with complete removal achieved in 35% of the specimens. CONCLUSIONS: Using the safe route above the optic canal, removal of 21% of the ACP can be achieved via EEA. Although substantially more of the ACP can be drilled by accessing the optic strut, the benefits of pursuing additional removal must be weighed against the significant risks of drilling in this narrow corridor bordered by the internal carotid artery, the third cranial nerve, and the optic nerve.

Estimating the Person-Specific Location of Pterion Based on Cranial Morphometry.

OBJECTIVE: Due to being the weakest sutural junction of the crania and relations with intracranial anatomical structures, the accurate location of the pterion is important for surgical approaches such as in pterional craniotomy. The aim of the study was to develop regression equations to estimate the person-specific accurate location of the pterion based on the cranial morphometry. MATERIALS AND METHODS: The study was conducted on 22 pterions located 11 dry skulls belonging to Anatomy Department of the Harran University, Medical Faculty. Twelve parameters related to pterion and 23 parameters related to the skull was measured using ImageJ software. SPSS 20.0 was performed for statistical analyses such as descriptive and comparative statistics and developing regression equations. RESULTS: Statistically significant difference wasn't observed between right and left sides. The 12 equations, such as P8:distance between pterion and the tip of the mastoid process= 63,780 + (1,366 × K6) - (2,786 × K7) + (1,342 × K11) - (1,029 × K13) + (2,102 × K14) - (1,710 × K15) - (0,517 × 22) Adjusted R2= 0.995 and Standard Errors = 1.221 were developed to estimate the accurate location of the pterion based on the cranial morphometry. CONCLUSIONS: In the previous studies, the mean distances of the pterion to certain landmarks on the crania were given. The authors developed formulas in order to estimate the accurate person-specific location of the pterion. The authors are convinced that the equations they have developed will help neurosurgeons in terms of surgical approaches.

Anatomy and Diseases of the Greater Wings of the Sphenoid Bone.

The greater wings of the sphenoid bone (GWS) comprise the components of the sphenoid bone that make up most of the posterior orbital wall and form the anterior and medial parts of the floor of the middle cranial fossa. Many important skull base foramina, which transmit vital neurovascular structures, are present in these paired wings on either side of the central body of the sphenoid bone. A wide variety of diseases can affect the GWS, ranging from benign osseus lesions to malignant primary and secondary bone abnormalities. The complex three-dimensional curved (winged) shape of the GWS and the wide array of pathologic entities that affect this bone can make it challenging for the radiologist to report the imaging findings accurately, especially in relation to the important skull base foramina. The authors describe a systematic approach to understanding the three-dimensional anatomy of the GWS and review important diseases, with the aid of imaging examples. Useful imaging "pearls" that can help in making specific diagnoses are provided throughout the article. ©RSNA, 2022.

Ossification of Pterygospinous and Pterygoalar Ligaments and Their Clinical Significance: An Anatomic Study.

ABSTRACT: Pterygospinous and pterygoalar ligaments, present in close proximity of foramen ovale at the base of skull, ossify creating pterygospinous and pterygoalar foramina, which causes problems in accessing retro and parapharyngeal spaces, trigeminal ganglion for treating trigeminal neuralgia by thermocoagulation and blocking it. Besides, these anatomical entities may compress nearby neurovascular structures causing discomfort to patients. Considering immense clinical significance associated with ossification of pterygospinous and pterygoalar ligaments, the study has been carried out. Aim of the study is to provide extended new classification related to pterygospinous and pterygoalar foramina and associated clinical significance. Seven hundred thirty skull bases were observed for variant ossification pterygospinous and pterygoalar ligaments and a new classification of occurrence of these anomalies has been proposed. Literature search revealed that incidence of formation of various forms of pterygospinous and pterygoalar foramina in world populations ranges between 1% and 31.2% and 1.3% and 62.4%, respectively. The highest incidence of complete pterygospinous foramen was observed in Brazilian population followed by Anatolian population and that of incomplete pterygospinous foramen also in Brazilian population. Various neurovascular structures are present in relation to pterygospinous and pterygoalar ligaments. Comprehension of foramina formed by ossification of these ligaments at the cranial base is imperative for proper planning and treating trigeminal neuralgia, clinical neuralgias involving oral and maxillofacial region and carrying out interventions like transfacial needle approaches to the foramen ovale and also for evaluating skull base radiographs. Therefore, thorough knowledge of these entities is of utmost use to anesthesiologists, dentists, and oral maxillofacial surgeons and neurosurgeons.

Complications According to the Handling of the Pterygoid Plate During Bimaxillary Surgery.

BACKGROUND: During bimaxillary surgery, manipulation of the pterygoid plate is required to facilitate movement of the maxilla. This study examined the complications that occurred after handling the pterygoid plate during a Le Fort I osteotomy. PATIENTS AND METHODS: This study compared and analyzed complications according to the pterygoid plate handling method in 80 patients who underwent bimaxillary surgery at Pusan National University Dental Hospital from December 2015 to July 2020. The pterygoid plate was fractured or removed intentionally only if it interfered with the maxilla. Otherwise, it was not treated. The complications during surgery and the follow-up period were investigated. RESULTS: Fourteen patients experienced complications, of which excessive bleeding, hearing problems, and nonunion were encountered in 10, 2, and 2 patients, respectively. Of the 10 patients with excessive bleeding patients, the pterygoid plate was manipulated in 8 patients, which was controlled during surgery. Two patients complained of hearing loss with ear congestion immediately after surgery; both patients improved spontaneously within 1 month. Two nonunion patients underwent plate refixation at least 6 months postoperatively, and normal healing was achieved afterward. CONCLUSIONS: Fracture and removal of the pterygoid plate during orthognathic surgery did not significantly affect the occurrence of complications during and after surgery.

Incomplete petrosphenoidal foramen: morphological and morphometric analysis and the proposal of a classification study in Brazilian dry skulls / Foramen petrosfenoidal incompleto: análisis morfológico y morfométrico y propuesta de clasificación: estudio en cráneos secos brasileños

SUMMARY: The complete petrosphenoidal foramen, or canal, is an eventual and atavistic bony formation at the boundary between the posterior and middle cranial fossa, by occurrence of ossification of the superior petrosphenoidal ligament. This ligament ossification, which has important clinical and surgical significance, can be complete or incomplete, in variable degrees, and is associated with the passageway of neurovascular structures, such as the abducens nerve and the inferior petrosal sinus. This study, conducted with 175 dry skulls that belong to the University of São Paulo's collection (USP), São Paulo, Brazil, established criteria for a morphological classification of the incomplete petrosphenoid foramen in nine types. In addition, anatomical parameters were established for the morphometric determination of two diameters: the Oblique Diameter (ObDi) and the Maximum Transverse Diameter (MTD). Thus, of the 175 skulls, 146 (83.42 %) presented some of the incomplete forms of the petrosphenoid foramen, and 43 skulls (29.45 %), due to their conservation characteristics, were habilitated to the morphological study, in the classification and in the morphometry (the types I and II of our classification). The type II (incomplete foramen with bony projections of the petrosal tubercle, of the margin of the dorsum of the hypophyseal fossa or of the posterior clinoid process with a distance between them greater than 1mm) and type V (incomplete foramen with a bony projection only in one of the referential structures - posterior clinoid process) were the most common in this study (50 % of the 86 hemiskulls). Morphometry was attributed only to the types: I selar (incomplete foramen with bony projections from the petrosal tubercle and the margin of the dorsum of the hypophyseal fossa with a distance between them less than or equal to 1mm) and to the type II of this classification. The type I selar (9.3 % of the 43 skulls) resulted in an average of 3.25 mm of MTD and 4.63 mm, on average, of ObDi. The type II (25.58 % of the 43 skulls) showed, on average, 4.93 mm of MTD and 7.01 mm of ObDi.

RESUMEN: El foramen o canal petroesfenoidal completo es una formación ósea eventual y atávica en el límite entre las fosas craneal posterior y media, por osificación del ligamento petroesfenoidal superior. Esta osificación del ligamento, que tiene un importante significado clínico y quirúrgico, puede ser completa o incompleta, en grados variables, y está asociada al paso de estructuras neurovasculares, como el nervio abducente y el seno petroso inferior. Este estudio se realizó en 175 cráneos secos pertenecientes a la colección de la Universidad de São Paulo (USP), São Paulo, Brasil. Se establecieron criterios para una clasificación morfológica del foramen petrosfenoidal incompleto en nueve tipos. Además, se establecieron parámetros anatómicos para la determinación morfométrica de dos diámetros: el Diámetro Oblicuo (ObDi) y el Diámetro Transversal Máximo (MTD). Así, de los 175 cráneos, 146 (83,42 %) presentaron alguna de las formas incompletas del foramen petrosfenoidal, y 43 cráneos (29,45 %), por sus características de conservación, fueron habilitados para el estudio morfológico, en la clasificación y en la morfometría (los tipos I y II de nuestra clasificación). El Tipo II (foramen incompleto con proyecciones óseas del tubérculo petroso, del margen del dorso de la fosa hipofisaria o del proceso clinoides posterior con una distancia entre ellos mayor de 1 mm) y el Tipo V (foramen incompleto con proyección ósea solamente en una de las estructuras referenciales - proceso clinoides posterior) fueron los más comunes en este estudio (50 % de los 86 hemiscráneos). La morfometría se atribuyó únicamente al Tipo I selar (foramen incompleto con proyecciones óseas desde el tubérculo petroso y el margen del dorso de la fosa hipofisaria con una distancia entre ellos menor o igual a 1mm) y al Tipo II de esta clasificación. El Tipo I selar (9,3 % de los 43 cráneos) resultó en un promedio de 3,25 mm de MTD y 4,63 mm, en promedio, de ObDi. El Tipo II (25,58 % de los 43 cráneos) mostró, en promedio, 4,93 mm de MTD y 7,01 mm de ObDi.

Anatomic Variation for the Endoscopic Endonasal Transsphenoidal Approach.

Knowledge of anatomy and its variations is the key to safe and efficient surgery. The endoscopic endonasal route to the sella has evolved to become the preferred route to access a wide variety of diseases. We describe the skeletal, vascular, and neural anatomic variations that could be encountered from the nasal phase, through the sphenoid phase, to the sellar phase of the operative exposure. A preoperative checklist is also provided.

Morphometric analyses of the caroticoclinoid and interclinoid foramina: a study in Brazilian dry skulls / Análisis morfométricos del foramen caroticoclinoideo e interclinoideo: un estudio en cráneos secos brasileños

SUMMARY: The caroticoclinoid (CF) and the interclinoid (IF) foramina are variant formations of the middle cranial fossa, which result from idiopathic and possibly atavistic ossifications of the caroticoclinoid and interclinoid ligaments, respectively. Topographically, these foramina are intimately associated, to varying degrees, depending on their conformations, with the neurovascular elements of the paraclinoid region and have important clinical and surgical significance. Thus, this study, conducted from 38 dry skulls belonging to the shared collection of the Federal University of Juiz de Fora, Governador Valadares campus, revealed 11 skulls (28.95 %) with one of the two complete formations - the caroticoclinoid or the interclinoid, and in 6 skulls the caroticoclinoid foramen occurred uni or bilaterally. As a result, 50 % of these skulls presented the CF exclusively on the right (or 62.5 % of the total number of variant foramina), with an average transverse diameter of 4.91 mm and 5.8 mm AP (anteroposterior) diameter and an average area of 22.5 mm2. Concerning the IF, the findings occurred in 5 skulls with variable distributions between the clinoid processes and lateralities. The average length of the bone bridges in the IF was 7.7 mm. In conclusion, detailed anatomical knowledge of the caroticoclinoid and the interclinoid foramina is fundamental to the practice of neurosurgical procedures, since they have intimate relationships at a location of high structural complexity.

RESUMEN: El foramen caroticoclinoideo (FC) y el foramen interclinoideo (IC) son formaciones variables de la fosa craneal media, que resultan de osificaciones idiopáticas y posiblemente atávicas de los ligamentos caroticoclinoideo e interclinoideo, respectivamente. Estos forámenes están íntimamente asociados topográficamente en diversos grados, dependiendo de sus conformaciones, con los elementos neurovasculares de la región paraclinoidea y tienen importancia clínica y quirúrgica. Así, este estudio, realizado a partir de 38 cráneos secos pertenecientes a la colección compartida de la Universidad Federal de Juiz de Fora, campus Governador Valadares, reveló 11 cráneos (28,95 %) con una de las dos formaciones completas: el FC o el IC, y en 6 cráneos el FC se presentó uni o bilateralmente. Como resultado, el 50 % de estos cráneos presentaba el FC exclusivamente a la derecha (o el 62,5 % del total de forámenes variantes), con un diámetro transversal medio de 4,91 mm y un diámetro anteroposterior medio de 5,8 mm y un área promedio de 22,5 mm2. En cuanto a la FI, los hallazgos se presentaban en 5 cráneos con distribuciones variables entre los procesos clinoides y lateralidades. La longitud media de los puentes óseos en el FI fue de 7,7 mm. En conclusión, el conocimiento anatómico detallado de los forámenes caroticoclinoideo e interclinoideo resulta fundamental para la práctica de procedimientos neuroquirúrgicos, ya que presentan relaciones íntimas en un lugar de alta complejidad estructural.

Anatomical variations and morphometric study of pterion in a Thai population associated with clinical implications / Variaciones anatómicas y estudio morfométrico del pterion en una población tailandesa asociada con implicaciones clínicas

SUMMARY: The objective of this study was to consider the type of variation and to estimate the landmarks for localizing the pterion. One hundred twenty Thai dry skulls were selected randomly from the Forensic Osteology Research Center, Faculty of Medicine, Chiang Mai University. The distances of the parameters were measured via Vernier caliper. The sphenoparietal type is the most dominant in the Thai population with 88.75 %. In the male, the distance of the midglabella to the pterion was 9.94?0.64 mm The distance of the frontozygomatic suture to the pterion was 35.41?4.38 mm The distance of the zygomatic arch to the pterion was 39.39?4.69 mm and the distance of the mastoid process tip to the pterion was 86.88?4.44 mm In the female, the distance of the midglabella to the pterion was 9.27?0.63 mm The distance of the frontozygomatic suture to the pterion was 33.08?4.12 mm The distance of the zygomatic arch to the pterion was 33.08?4.12 mm and the distance of the mastoid process tip to the pterion was 83.62?5.16 mm. The pterion approach is the most popular method for neurosurgical procedures, and it provides anatomical variations in the pattern. The sphenoparietal type of pterion is the most common form and the stellate type of pterion is the least common form in Thai skulls. Sex influences the location of the pterion. These findings will be of importance to predict the pterion type in Thai skull and estimate the localization of pterion by using a bony landmark. Knowledge of the precise location of the pterion is an important landmark in the neurosurgical approach.

RESUMEN: El objetivo de este estudio fue considerar el tipo de variación del pterion y estimar los puntos de referencia para localizarlo. Se seleccionaron al azar 120 cráneos secos de individuos tailandeses del Centro de Investigación de Osteología Forense de la Facultad de Medicina de la Universidad de Chiang Mai. Las distancias de los parámetros se midieron mediante un caliper Vernier. El tipo esfenoparietal es el más dominante en la población tailandesa con 88,75 %. En el hombre, la distancia de la glabella al pterion fue de 9,94 ? 0,64 mm. La distancia de la sutura frontocigomática fue de 35,41 ? 4,38 mm La distancia del arco cigomático fue de 39,39 ? 4,69 mm y la distancia del ápice del proceso mastoideo al pterion fue de 86,88 ? 4,44 mm. En la mujer, la distancia de la glabella al pterion fue de 9,27 ? 0,63 mm. La distancia de la sutura frontocigomática al pterion fue de 33,08 ? 4,12 mm. La distancia del arco cigomático al pterion fue de 33,08 ? 4,12 mm y la distancia del ápice proceso mastoideo al pterion fue de 83,62 ? 5,16 mm. El abordaje del pterion es el método más utilizado para procedimientos neuroquirúrgicos y proporciona variaciones anatómicas en el patrón. El tipo esfenoparietal del pterion es la forma más común y el tipo estrellado del pterion es la forma menos común en los cráneos tailandeses. El sexo influye en la ubicación del pterion. Estos hallazgos serán importantes para predecir el tipo de pterion del cráneo en tailandeses y a la vez estimar su localización mediante el uso de un punto de referencia óseo. El conocimiento de la ubicación precisa del pterion es un hito impor- tante en el abordaje neuroquirúrgico.

The pterygospinous foramen (Civinini) and the pterygoalar (crotaphitico-buccinatorius): laboratory findings / El foramen pterigoespinoso (Civinini) y el pterigoalar (crotafítico-buccinatorius): hallazgos de laboratorio

SUMMARY: The Pterygospinous foramen and pterygoalar foramen (crotaphitico-buccinatorius) are variant and atavic formations of the skull base and arise respectively from complete or incomplete idiopathic ossifications of the pterygospinous and pterygoalar ligaments. By proximity with areas of relevance for diagnosis and surgery, such as access pathways to the parapharyngeal and retropharyngeal spaces, it is necessary to be aware of these conditions due to the difficulties generated in surgical maneuvers and the promotion of compressive syndromes of mandibular nerve branches. This study was conducted on 45 samples of dry skulls and disarticulated sphenoid bones belonging to the collection of the Federal University of Juiz de Fora, Governador Valadares campus, Minas Gerais, Brazil. Our results indicated a total incidence of complete and incomplete pterygospinous and pterygoalar foramen (crotaphitico- buccinatorius) in 15, 5 % (7 skulls), with a higher incidence for the incomplete form of pterygospinous foramen (Civinini foramen) in 4 skulls (8.8 %), with 3 presenting unilaterally and 3 presenting bilaterally. The pterygoalar foramen (crotaphitico-buccinatorius or Hyrtl) was noted bilaterally in 1 of the skulls (2.2 %). The pterygospinous foramen and pterygoalar foramen are important findings, sometimes incidental, of an area of great anatomical expressiveness and pathological occurrences, besides the indispensable and unclear studies of phylogenetic order.

RESUMEN: El foramen pterigoespinoso y el foramen pterigoalar (crotafítico-buccinatorius) son formaciones variantes y atávicas de la base del cráneo y surgen respectivamente de osificaciones idiopáticas completas o incompletas, de los ligamentos pterigoespinoso y pterigoalar. Debido a la proximidad con áreas de relevancia para el diagnóstico y la cirugía, como las vías de acceso a los espacios parafaríngeo y retrofaríngeo, es necesario conocer estas condiciones por las dificultades que se generan en las maniobras quirúrgicas. Este estudio se realizó en 45 muestras de cráneos secos y huesos esfenoides desarticulados pertenecientes a la colección de la Universidad Federal de Juiz de Fora, campus Governador Valadares, Minas Gerais, Brasil. Nuestros resultados indicaron una incidencia total de foramen pterigoespinoso y pterigoalar completo e incompleto (crotafítico-buccinatorius) en el 15,5 % (7 cráneos), con una mayor incidencia de la forma incompleta de foramen pterigoespinoso (agujero de Civinini) en 4 cráneos (8,8 %), con 3 de presentación unilateral y 3 de presentación bilateral. El foramen pterigoalar (crotaphitico-buccinatorius o Hyrtl) se observó bilateralmente en 1 de los cráneos (2,2 %). El foramen pterigoespinoso y pterigoalar son hallazgos importantes, a veces incidentales, de un área de gran expresividad anatómica y ocurrencias patológicas, además de los estudios indispensables y poco claros de orden filogenético.

The historical perspective in approaches to the spheno-petro-clival meningiomas.

The current literature regarding surgical treatment for tumors in the sphenopetroclival (SPC) region is merely scarce. Through a comprehensive literature review, we investigated the indications, outcomes, and complications of different surgical approaches to the SPC meningiomas. Given its complicated relationship between these slow-progression tumors and some critical neurovascular structures in the SPC region, surgical treatment of these tumors faces the challenge of achieving a maximal grade of resection, while preserving patient functionality. The development of new surgical techniques and approaches in recent years have permitted the advancement in the treatment of these tumors, with acceptable rates of morbidity and mortality. The choice of a surgical approach as a treatment for the lesion depends mainly on the type of tumor extension, surgeon's preferences, and the displacement of neurovascular structures. Rather than focusing on one single strategy of treatment, the skull-base surgeon should tailor the approach based on the origin and features of the lesion; as well as the peculiarities of the surgical anatomy. This strategy aims to decrease morbidity and to optimize tumor resection and patient quality of life.

Surgical anatomy and nuances of the expanded transpterygoid approach to the pterygopalatine fossa and upper parapharyngeal space: a stepwise cadaveric dissection.

BACKGROUND: Superb knowledge of anatomy and techniques to remove the natural barriers preventing full access to the most lateral aspect of the skull base determines the ease of using the transpterygoid approach (ETPA) as the main gateway for all the coronal planes during endonasal surgeries. METHODS: Throughout stepwise image-guided cadaveric dissections, we describe the surgical anatomy and nuances of the ETPA to the pterygopalatine fossa (PPF) and upper parapharyngeal space (UPPS). CONCLUSION: The ETPA represents a lateral extension of the midline corridor and provides a valuable route to access the PPF/UPPS. Major landmarks for this EEA are the infraorbital canal, sphenopalatine foramen, and vidian nerve. It comprises the removal of the palatine bone, posterior wall of the maxillary sinus, and PPF transposition to drill the pterygoid process.

Location of the Sphenoid Sinus Ostium in Relation to Adjacent Anatomical Landmarks.

PURPOSE: The variability of sphenoid pneumatization and its relationship with the surrounding structures has been suggested. The aim of this study was to examine the effect of the surrounding bony structures on the position of the sphenoid ostium (SO). METHODS: A prospective radiological review of computed tomography images of paranasal sinuses of 150 patients (300 sides) was conducted. Parameters investigated included the presence of Onodi cells, sphenoid rostrum pneumatization, and the type of sphenoid pneumatization on the coronal and sagittal planes. Their effect was studied on the vertical and horizontal plane using lines of measurement 1 through 5. RESULTS: The most common location of the SO on the horizontal plane was found to be in the middle third and was significantly affected by the rostrum pneumatization (P value <.001) and sphenoid pneumatization on the coronal plane (P value = .018). The location of the SO on the vertical plane was most commonly in the middle third. It was significantly affected by Onodi cell pneumatization (P value = .021) as well as the sphenoid height (P value <.001). CONCLUSIONS: Pneumatization of the sphenoid sinus and adjacent bony structures can affect the location of the SO. Presence of rostrum pneumatization and lateral sphenoid pneumatization shift the SO laterally. Presence of Onodi cell and low sphenoid roof shift the SO inferiorly. These variations need to be studied carefully before surgery in order to avoid operative complications.