Radiologic evaluation of the Vidian canal in the pediatric population.

PURPOSE: This examination aimed to display the size and topographic position of the Vidian canal (VC) in normal children. METHODS: 180 pediatric subjects aged 1-18 years were included this computed tomography examination. The distances of VC to certain landmarks, and VC length were measured. The locations of VC according to the sphenoid sinus, and the medial plate of pterygoid process were classified as three types, separately. RESULTS: The distances of VC to the vomerine crest, midsagittal plane, round foramen, and the superior wall of sphenoid sinus were measured as 12.68 ± 3.17 mm, 10.76 ± 2.52 mm, 8.62 ± 2.35 mm, and 14.16 ± 5.00 mm, respectively. The length and angle of VC were measured as 12.00 ± 2.52 mm, and 16.60 ± 9.76°, respectively. According to the sphenoid bone, VC location was identified as Type 1 in 113 sides (47.5%), as Type 2 in 70 sides (29.4%), and as Type 3 in 55 sides (23.1%). According to the medial plate of pterygoid process, VC location was identified as Type A in 274 sides (76.1%), as Type B in 55 sides (15.3%), and as Type C in 31 sides (8.6%). VC location types correlated with pediatric ages, but not sex or side. CONCLUSION: With advancing pediatric age, the protrusion of VC into the sphenoid sinus increases, and VC shifts from medial to lateral side of the medial plate of pterygoid process.

A computed tomography (CT)-based morphometric study of various skull base parameters and their anatomical relationships relevant to endoscopic endonasal skull base surgery.

Background: Endoscopic skull base surgery requires a thorough understanding of skull base anatomy. Orientation to regional anatomy to avoid complications like internal carotid artery injury can be assisted by knowledge of certain bony landmarks. These landmarks are themselves highly variable structures. This study focuses on the radiological morphometric characterization of these landmarks, which can be of great assistance to surgeons for better planning of endoscopic skull base approaches. Methods: Computed tomography scans of patients without skull base pathologies were analyzed retrospectively for the following parameters - Vidian canal (VC) length, VC and foramen rotundum (FR) distance from midline, the angle between the axis of VC and petrous internal carotid artery (pICA) and between VC and palatovaginal canal, the horizontal, vertical and direct distances between VC and FR and the patterns of sphenoid sinus (SS) pneumatization. Results: The VC-pICA angle was more obtuse and VC and FR were placed farther off the midline on the left as compared to the right side. Similarly, the distances between VC and FR were more on the left side. The VC length and distance of VC and FR from the midline were longer in males than in females. The VC-pICA angle was more obtuse in females. The post-sellar variant was the predominant pneumatization pattern seen (57.9%), and the incidence of lateral recess pneumatization was 15%. Conclusion: The results of our study can be utilized for a better understanding of the anatomy of the skull base. In skull base pathologies with distorted anatomical landmarks, a basic understanding of their interrelations can be used to have a better anatomical orientation. All these measures can help in avoiding complications and make extended endoscopic approaches safe.

The Displacement Patterns of Petrous Internal Carotid Artery and Its Morphometric Relations with Vidian Canal in Petroclival Chondrosarcomas Relevant to Extended Endoscopic Endonasal Approaches: A Radiological Study.

BACKGROUND: Extended endoscopic endonasal approaches (EEAs) to petroclival chondrosarcomas (PCs) require a thorough understanding of skullbase anatomy, especially the anatomy of petrous internal carotid artery (pICA), as ICA injury is the most dreaded complication of extended EEAs. We conducted this study to determine the displacement patterns of pICA in patients with PCs. METHODS: Contrast enhanced computed tomography scan and angiography images of patients with PCs were analyzed for following parameters-antero-posterior, cranio-caudal, medio-lateral, and direct distances between anterior genu of petrous internal carotid artery (AGpICA) and posterior end of Vidian canal (pVC). pICA encasement/narrowing by tumor was noted on magnetic resonance imaging. RESULTS: We studied 11 patients with histopathologically proven PCs. pICA encasement/narrowing and pVC destruction were observed in one patient each. The mean antero-posterior and cranio-caudal distances on tumor side/normal side were 7.7 ± 1.9/6.4 ± 1.0 mm & 4.5 ± 1.5/3.4 ± 0.9 mm, respectively. The overall displacement was posterior & superior. Medio-lateral displacement was seen in 4 patients (lateral in 3 and medial in 1). In rest, AGpICA was centered on pVC. The mean direct distance was 9.4 ± 2.5 mm. In 3 patients with displacement seen in all three axes, direct distance was measured by the "cuboid method." Overall, posterior-superior-lateral, posterior-superior, and anterior-inferior were the common displacement patterns of AGpICA relative to pVC. CONCLUSIONS: The displacement patterns of AGpICA in PCs are variable. An individualized approach with meticulous analysis of preoperative imaging can help in determining the relation between AGpICA and pVC. This detailed morphometric information can facilitate better orientation to altered anatomy, which can be helpful in preventing pICA injury during extended EEAs.

Vidian Canal as a Transcranial Landmark: Anatomy, Technique, and Illustrative Cases.

Objective The vidian nerve can be accessed in transcranial approaches in carefully selected patients to ensure its preservation and to serve as a landmark for sphenoid sinus entry. This report is to review a technique, evaluate it in laboratory settings, and present two illustrative cases. Design The study involves cadaveric dissection and illustrative cases. Setting The study conducted in a cadaveric dissection laboratory. Participants The object of the study is one cadaveric head and two illustrative clinical cases. Main Outcome Measures Two cases using this approach were illustrated, and a cadaver dissection was performed in a step-by-step fashion. Results: The vidian canal can be accessed by drilling the anterolateral triangle. Two illustrated cases were presented; in one, the vidian nerve was used as part of a corridor to access the sphenoid sinus for tumor delivery, and in the other, the technique was used to find and preserve the vidian nerve during transcranial resection. Conclusion Careful identification of the vidian canal in transcranial surgery is a beneficial technique in carefully selected cases which allows identification of the nerve both for its preservation in selected cases and to create the vidian-maxillary corridor for tumor resection. Knowing the anatomy and pneumatization variants is important in the surgical approach.

Anatomical relationship of pterygoid process pneumatization and vidian canal / Relação anatômica da pneumatização do processo pterigoide e o canal vidiano

Abstract Introduction The vidian canal acts as landmark for the identification of the petrous carotid artery, especially during extended endoscopic endonasal approaches in cranial base surgeries. In order to localize the canal and to understand the relationship of pneumatization of pterygoid process to the type of vidian canal, this study was designed. Objectives The objective was to describe the anatomical relationship of pneumatization of the pterygoid process with types of vidian canal. The length of vidian canal, relationship to medial plate of pterygoid process and relationship to the petrous part of internal carotid artery were evaluated. Methods Head computer tomography scans of 52 individuals for suspected paranasal pathology were studied. The degree of sphenoid sinus pneumatization, pterygoid process pneumatization and types of vidian canal (type 1, 2 and 3) were noted. The length of vidian canal, distance from the plane of medial pterygoid plate and relation of vidian canal to the junction of petrous and Gasserian (ascending) part of internal carotid artery was noted. Results 46 (92%) sphenoid sinuses were of the sellar variety. Out of 104 sides that were studied, 57 sides demonstrated a pneumatised pterygoid process and 47 were not pneumatised. In 49 sides (47.1%) the vidian canal was on the same plane as that of the medial pterygoid plate in the coronal section. The vidian canal partially protruded into the sphenoid sinus (type 2) was the most common type (50.9%), found both on right and left sides. There is a statistically significant association between the pterygoid process pneumatization and occurrence of type 2 and type 3 vidian canal configuration. The average length of the vidian canal was 16.16 ± 1.8 mm. In 96 sides, the anterior end of vidian canal was inferolateral to petrous part of internal carotid artery in the coronal plane. Conclusion Pneumatization of the pterygoid process indicates either type 2 or type 3 vidian canal configuration.

Resumo Introdução O canal vidiano atua como ponto de referência para a identificação da artéria carótida petrosa, especialmente durante abordagens endoscópicas endonasais extensas em cirurgias de base do crânio. Este estudo foi projetado com o objetivo de localizar o canal vidiano e entender a relação da pneumatização do processo pterigoide sobre o tipo de canal. Objetivos Descrever a relação anatômica da pneumatização do processo pterigoide com os tipos de canal vidiano. Foram avaliados o comprimento do canal vidiano, a relação com a placa medial do processo pterigoide e com a porção petrosa da artéria carótida interna. Método Foram estudadas tomografias computadorizadas de 52 indivíduos submetidos a tomografia computadorizada de cabeça por suspeita de doença em seio paranasal. Foram observados o grau de pneumatização do seio esfenoidal, a pneumatização do processo pterigoide e os tipos de canal vidiano (Tipos 1, 2 e 3). Observou-se o comprimento do canal vidiano, a distância do plano da placa pterigoide medial e a relação do canal vidiano com a junção da porção petrosa e gasseriana (ascendente) da artéria carótida interna. Resultados Eram do tipo selar 46 (92%) seios esfenoidais. Dos 104 lados estudados, 57 eram do processo pterigoide pneumatizado e 47 não eram pneumatizados. Em 49 lados (47,1%), o canal vidiano estava no mesmo plano que o da placa pterigoide medial na seção coronal. O canal vidiano em protusão parcial no seio esfenoidal (tipo 2) foi o tipo mais comum (50,9%), encontrado nos lados direito e esquerdo. Houve uma associação estatisticamente significante entre a pneumatização do processo pterigoide e a ocorrência da configuração do canal vidiano tipo 2 e tipo 3. O comprimento médio do canal vidiano foi de 16,16 ± 1,8 mm. Em 96 lados, a extremidade anterior do canal vidiano era inferolateral à porção petrosa da artéria carótida interna no plano coronal. Conclusão A pneumatização do processo pterigoide indica a configuração do canal vidiano tipo 2 ou tipo 3.

Sphenoid sinus pneumatization: the good, the bad, and the beautiful.

PURPOSE: To study different types of extension of sphenoid sinus pneumatization detected by CT and examine their correlation with other anatomical variants. METHODS: Sphenoid sinus pneumatization was characterized (780 hemi-sinuses) on CT scans. Its incidence and correlations with related anatomical variants were evaluated. Dimensions of surgical window were measured in the lateral type, where pneumatization extends beyond a line connecting Vidian (pteregoid) canal (VC) and foramen rotundum (FR). RESULTS: The lateral recess of the sphenoid sinus was pneumatized in 27.3% of patients with a mean width of 7.59 mm. The distance separating the FR and the VC correlated strongly with the depth of the lateral recess. There was significant positive correlation between pneumatization of lateral recess and Vidian nerve prominence to other pneumatization patterns (lesser sphenoid, frontal, and Maxillary sinuses) (p < 0.0001). Lateral recess pneumatization in coronal cuts was also significantly correlated with anterior-posterior sphenoid pneumatization in sagittal cuts (p < 0.0001). CONCLUSION: Pre-operative assessment of sphenoid sinus pneumatization is essential in the endoscopic approach to skull base structures to facilitate surgical access and avoid injury of the nearby structures. Our study showed significant correlation among anatomical variants and different measurements which allows the surgeon to predict abnormal anatomy with high accuracy.

Anatomical relationship of pterygoid process pneumatization and vidian canal.

INTRODUCTION: The vidian canal acts as landmark for the identification of the petrous carotid artery, especially during extended endoscopic endonasal approaches in cranial base surgeries. In order to localize the canal and to understand the relationship of pneumatization of pterygoid process to the type of vidian canal, this study was designed. OBJECTIVES: The objective was to describe the anatomical relationship of pneumatization of the pterygoid process with types of vidian canal. The length of vidian canal, relationship to medial plate of pterygoid process and relationship to the petrous part of internal carotid artery were evaluated. METHODS: Head computer tomography scans of 52 individuals for suspected paranasal pathology were studied. The degree of sphenoid sinus pneumatization, pterygoid process pneumatization and types of vidian canal (type 1, 2 and 3) were noted. The length of vidian canal, distance from the plane of medial pterygoid plate and relation of vidian canal to the junction of petrous and Gasserian (ascending) part of internal carotid artery was noted. RESULTS: 46 (92%) sphenoid sinuses were of the sellar variety. Out of 104 sides that were studied, 57 sides demonstrated a pneumatised pterygoid process and 47 were not pneumatised. In 49 sides (47.1%) the vidian canal was on the same plane as that of the medial pterygoid plate in the coronal section. The vidian canal partially protruded into the sphenoid sinus (type 2) was the most common type (50.9%), found both on right and left sides. There is a statistically significant association between the pterygoid process pneumatization and occurrence of type 2 and type 3 vidian canal configuration. The average length of the vidian canal was 16.16 ±â€¯1.8 mm. In 96 sides, the anterior end of vidian canal was inferolateral to petrous part of internal carotid artery in the coronal plane. CONCLUSION: Pneumatization of the pterygoid process indicates either type 2 or type 3 vidian canal configuration.

Sphenoid Sinus and Related Neurovascular Structures-Anatomical Relations and Variations on Radiology-A Retrospective Study.

The aim of this study was to evaluate sphenoid sinus pneumatisation and its anatomical relation with adjacent neurovascular structures in Indian population. We performed a retrospective cross-sectional study, in which the pattern of sphenoid sinus pneumatization was studied on high-resolution computed tomography scans (n = 400), and association of the optic nerve, vidian canal and foramen rotundum along with related morphometric measurements were studied. Out of 400 CT scans, 60.5% were males. Majority had sellar type of pneumatization (89.5%) and single intersinus septum (68%). The most common configuration of relation of optic nerve canal was DeLano type 2 (34.75%). Vidian canal (VC) and Foramen rotundum (FR) were found dehiscent in 40.5% and 6.38% respectively. Average distance of FR from midline on right and left side was 16.3 ± 2.19 mm and 16.7 ± 2.23 mm respectively. Average distance of VC from midline on right and left side was 12.4 ± 5.84 mm and 12.4 ± 4.18 mm respectively. Average right FR to VC distance was 4.17 ± 2.16 mm and left FR to VC was 4.44 ± 2.20 mm. Anatomical variations of the sphenoid sinus are well known. In the present study, we have tried to highlight the importance of knowledge of various anatomical variations in relations to sphenoid sinus as they are critical in planning of surgery. Pre-operative radiological study and correlation is inevitable to assess type and extent of sinus pneumatisation, bony dehiscence and septal terminations to avoid injury to vital structures.

Assessing the abilities of senior otolaryngology residents and graduated otolaryngologists in recognizing skull base elements in axial CT scan: proposing a new method for differentiating superior orbital fissure and optic canal.

BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate the ability of recognizing some important elements of the skull base in axial CT-scan cuts, including the optic canal (OC), superior orbital fissure (SOF), vidian canal (VC), foramen rotundum (FR), jugular foramen (JF) and hypoglossal canal (HC). METHODS: In this study, 25 otolaryngology residents and 25 recently graduated otolaryngologists were evaluated in terms of their recognition of skull base elements, using 30 axial CT-scan cuts. Two months later, the exam related to skull base CT scans was taken in groups after a brief anatomy courses for otolaryngology residents. RESULTS: The percentage of correct answers from otolaryngology residents regarding OC, SOF, VC, FR, JF, and HC in the first exam were 74 ± 26, 47 ± 34, 65 ± 30, 41 ± 38, 58 ± 26, and 68 ± 32, respectively. The correct answer for each element was similar between groups, and the differences were not statistically significant (p > 0.05). p value for the differences observed regarding the percentage of correct answers for the second exam between trained otolaryngology residents and recent otolaryngology graduates regarding OC and JF was no significant (p > 0.05) but significant for the other elements with better result in trained otolaryngology residents and most for SOF (p > 0.0001). CONCLUSION: This study showed that the ability of recognition for the mentioned elements in axial CT-scan cuts was low among otolaryngology residents and graduated otolaryngologists. The proposed novel method for distinguishing SOF from OC had a powerful and long-lasting effect on trainee.

Can palatovaginal canal be the site of origin of juvenile nasopharyngeal angiofibroma?

Juvenile nasopharyngeal angiofibroma (JNA) is the most common benign tumor of the nasopharynx. For reasons unknown, this tumor is found almost always in male population. However, site of origin of JNA is still an enigma. Previously, JNA was considered to arise from the superior aspect of sphenopalatine foramen. Over last decade, the vidian canal was considered to be the more specific and likely site of origin. However, based on our observations, we believe this hypothesis to be anomalous as it does not explain major blood supply, pattern of skull base erosion in early stage of tumor and newer studies on electron microscopic and immunopathological findings. To explain these anomalies, we hypothesize the site of origin to be palato-vaginal canal.

[The role of palatovaginal canal and sphenopalatine artery in the localization of vidian canal during vidian neurotomy].

Objective:To explore the role of palatovaginal canal and sphenopalatine artery in the localization of pterygoid canal during pterygoid neurotomy. Method:55 patients with or without nasal polyps were divided into two groups: group A（twenty-nine cases, anterior wall approach of sphenoid sinus） and group B（twenty-six cases, middle nasal meatus approach）. All patients underwent unilateral vidian neurectomy under nasal endoscope. The vidian canal was located by palatal canal and sphenopalatine artery in group A and B, respectively. Result:The vidian canal was located successfully in all patients, with small wound, fast postoperative recovering. There was no irreversible complication. Conclusion:The relationship between the palatovaginal canal, sphenopalatine artery and the external orifice of vidian canal is constant, which can be used as an anatomical marker of vidian neurotomy.

Morphometric assessment of important landmarks on skull intended for Vidian nerve surgery.

PURPOSE: The aim of our study was to determine guide parameters for clinicians by morphometric assessment of important landmarks on cranium intended for Vidian nerve surgery. METHODS: For the study, 23 half-skull bases, 40 skull bases and 40 skulls were obtained from the Department of Anatomy, Ege University Medicine Faculty. The vertical distances were measured using a digital caliper to the nearest 0.01 mm. RESULTS: The anterior opening of the Vidian canal (pterygoid canal) was observed as oval shaped on 57 specimens (31.1%), funnel shaped on 58 specimens (31.7%), round shaped on 64 specimens (35%) and septated on 4 specimens (2.2%). Vidian canal was embedded into the body of sphenoid on 55 specimens (52.4%) (embedded type) and protruded to sphenoidal sinus on 50 specimens (47.6%) (protruded type). 21 specimens of 50 were partial and 29 specimens were total. There were dehiscences on 21 specimens of 50 protruded type on the base of sphenoidal sinus (20%). Anterior opening of the Vidian canal was assessed according to medial lamina of pterygoid process. It was located medially in 169 of the specimens (92.3%) and laterally in 14 specimens (7.7%). CONCLUSION: Vidian canal and Vidian nerve are deeply located structures on skull. Vidian canal and surrounding structures are important landmarks for microsurgery and endoscopic approaches to Vidian nerve. We consider that knowledge of anatomical features of Vidian canal and preoperative imaging by CT (computed tomography) will be supportive when choosing and planning a safe surgical approach.

Vidian canal and sphenoid sinus: an MDCT and cadaveric study of useful landmarks in skull base surgery.

PURPOSE: To present the anatomical variations of vidian canal (VC) and sphenoid sinus (SS), relative to other anatomical landmarks of skull base area, which may be helpful for safer surgical approach to this area. MATERIALS: MDCT scans (128-row MDCT system) of 90 patients (mean age 62 years) and six cadaveric heads were studied, and the following parameters were evaluated: mean length and types of VC, distance between VC and foramen rotundum (FR) and optic canal (OC), position of the VC regarding the lateral pterygoid plate (MPTG) and petrous ICA, pneumatization of SS, position of intrasinus septum regarding ICA and OC, bone dehiscence and protrusion of ICA and OC into SS. Six cadaveric heads underwent MDCT and endoscopic dissection, and the type and length of VC were evaluated. The statistical significance was assessed using Chi-square (χ2) test. Significance level was set at p < 0.05. RESULTS: A statistical analysis was performed between the measurements at both sides, as well as between measurements in MDCT and dissection of the six cadaveric heads. Statistically significant difference was found between right and left sides in the horizontal and vertical distances between FR and VC, as well as between VC and OC. Also, there was a statistically positive correlation between type II of VC and lateral pneumatization on the right side. There was not statistically significant difference concerning VC type and length between MDCT and dissection measurements. CONCLUSION: Surgeons addressing skull base surgery must be familiar with the anatomical and positional variations of VC and SS in the preoperative CT images so as to avoid serious complications during surgery.

Morphometric analysis of vidian canal and its relations with surrounding anatomic structures by using cone-beam computed tomography.

BACKGROUND: We identified the vidian canal (VC) in a Turkish subpopulation on cone-beam computed tomography (CBCT) images and explored its anatomic relationships; the canal serves as an anatomic pathway during endonasal surgical approaches. MATERIALS AND METHODS: Coronal and axial CBCT images of 100 patients (50 males and 50 females) were evaluated (slice thickness and interval, 0.5 mm). We measured the length of the VC length, extent of VC pneumatisation into the sphenoid sinus, position of the VC relative to the medial pterygopalatine plate (MPP), pterygopalatine fossa (PPF) depth, and VC-VC, VC-MPP, and VC-foramen rotundum (FR) distances, the angle between the posterior end of the middle turbinate and the lateral part of the VC anterior opening, and the angle between the VC and the palatovaginal canal. RESULTS: The mean VC length was 13.09 ± 2.07 and 13.01 ± 2.12 mm on the right and left sides, respectively. Relative to the MPP, the VC was located medially in 54.5% of patients, on the same level in 36%, and laterally in 9.5%. Pneumatisation was of grade I in 24% of patients, grade II in 33%, grade III in 23.5%, and grade IV in 19.5%. The VC-FR and VC-MPP distances were significantly greater on the left side. The angle between the posterior end of the middle turbinate and the lateral part of the anterior VC opening was significantly greater on the right side. The VC-VC distance was significantly greater when the VC lay lateral to the MPP. CONCLUSIONS: Anatomic characteristics of the VC on CBCT images unique to Turkish populations should be kept in mind during surgery.

Study of the pterygoid canal (vidian canal) through images of cone beam computer tomography / Estudo do canal Pterigóideo (canal Vidiano) por meio de imagens de tomografia computadorizada de feixe cônico

Objective: The aim of this study was to evaluate the pterygoid canal (PC) by Cone Beam Computed Tomography (CBCT), establishing its configuration and proximity with anatomical structures. Material and Methods: We evaluated 398 CBCT exams, all from a public University radiology clinic archive. Four parameters were evaluated: single or double PC, distance between PC and the inferior part of the sphenoid sinus (SS), ratio of PC and SS and the distance between the PC and the foramen rotundum. Results: It was observed that most of the PC of the sample presented simple morphology, the most frequent type of relationship between the PC and the SS on both sides was the close contact with the wall. Among the cases that there were some distances between the PC and the inferior wall of the SS, the mean of this distance did not exceed 3.20 mm, being the left side (3.03 mm) slightly closer than the right (3.20 mm). Finally, the distances between the PC and the corresponding Foramen Rotundum are presented with mean values of 5.87 mm for the right side and 6.31 mm for the left side. Conclusion: CBCT examination is of paramount importance for PC identification; once in the studied sample, the mean values found evidence the close relation between the PC and the SS (AU)

Objetivo: O objetivo deste estudo foi avaliar o CP pela TCFC, estabelecendo sua configuração e proximidade com estruturas anatômicas. Material e Métodos: Foram avaliados 398 exames de TCFC, todos de um arquivo público da clínica de radiologia da Universidade. Foram avaliados quatro parâmetros: CP único ou duplo, distância entre PC e parte inferior do seio esfenoidal (SS), razão entre PC e SS e a distância entre o PC e o forame redondo. Resultados: Observou-se que a maioria dos CP da amostra apresentava morfologia simples, o tipo de relação mais frequente entre o CP e o SS de ambos os lados foi o contato próximo com a parede. Entre os casos em que houve algumas distâncias entre o CP e a parede inferior da ES, a média dessa distância não excedeu 3,20 mm, sendo o lado esquerdo (3,03 mm) um pouco mais próximo do que o direito (3,20 mm). Finalmente, as distâncias entre o PC e o forame redondo correspondente são apresentadas com valores médios de 5,87 mm para o lado direito e 6,31 mm para o lado esquerdo. Conclusão: O exame TCFC é de suma importância para a identificação do CP; uma vez na amostra estudada, os valores médios encontrados evidenciam a estreita relação entre o CP e o SS. (AU)

The anatomic analysis of the vidian canal and the surrounding structures concerning vidian neurectomy using computed tomography scans / Avaliação anatômica do canal vidiano e estruturas adjacentes por tomografia computadorizada para a neurectomia do vidiano

Abstract Introduction: The type of endoscopic approach chosen for vidian neurectomy can be specified by evaluating the vidian canal and the surrounding sphenoid sinus structures. Objective: The variations and morphometry of the vidian canal were investigated, focusing on the functional correlations between them which are crucial anatomical landmarks for preoperative planning. Methods: This study was performed using paranasal multidetector computed tomography images that were obtained with a section thickening of 0.625 mm of 250 adults. Results: The distributions of 500 vidian canal variants were categorized as follows; Type 1, within the sphenoid corpus (55.6%); Type 2, partially protruding into the sphenoid sinus (34.8%); Type 3, within the sphenoid sinus (9.6%). The pneumatization of the pterygoid process is mostly seen in vidian canal Type 2 (72.4%) and Type 3 (95.8%) (p < 0.001). The mean distances from the vidian canal to the foramen rotundum and the palatovaginal canal were greater in the vidian canal Type 2 and 3 with the pterygoid process pneumatization (p < 0.001). The prevalence of the intrasphenoid septum between the vidian canal and the vomerine crest and lateral attachment which ending on carotid prominence were much higher in vidian canal Type 3 than other types (p < 0.001). The mean angle between the posterior end of the middle turbinate and the lateral margin of the anterior opening of the vidian canal was measured as 33.05 ± 7.71°. Conclusions: Preoperative radiologic analysis of the vidian canal and the surrounding structures will allow surgeons to choose an appropriate endoscopic approach to ensure predictable postoperative outcomes.

Resumo Introdução: O tipo de abordagem endoscópica para a neurectomia do vidiano pode ser definido pela avaliação do canal do vidiano e das estruturas adjacentes aos seios esfenoidais. Objetivo: Investigar as variações e a morfometria do canal vidiano com enfoque nas suas correlações funcionais, pois são parâmetros anatômicos cruciais para o planejamento pré-operatório. Método: Esse estudo foi realizado utilizando-se imagens de tomografia computadorizada multidetectores dos seios paranasais com espessura de corte de 0,625 mm obtidas de 250 indivíduos adultos. Resultados: A distribuição das 500 variantes do canal vidiano foi categorizada da seguinte forma: Tipo 1, dentro do corpo ósseo esfenoidal (55,6%); Tipo 2, protrusão parcial no interior do seio esfenoidal (34,8%); Tipo 3, no interior do seio esfenoidal (9,6%). A pneumatização do processo pterigoide foi observada principalmente no canal vidiano Tipo 2 (72,4%) e Tipo 3 (95,8%) (p < 0,001). As distâncias médias do canal vidiano até o forame redondo e o canal palatovaginal foram maiores no canal vidiano do Tipo 2 e 3, com a pneumatização do processo pterigoide (p < 0,001). A presença do septo intraesfenoidal entre o canal vidiano e a crista vomeriana e a extensão lateral, que termina na proeminência da carótida, foi muito maior no canal vidiano Tipo 3 do que nos outros tipos (p < 0,001). A angulação média entre a cauda da concha média e a margem lateral da abertura anterior do canal vidiano foi de 33,05° ± 7,71°. Conclusões: A análise radiológica pré-operatória do canal do vidiano e das estruturas circunjacentes permitem ao cirurgião escolher uma abordagem endoscópica apropriada e prever resultados pós-operatórios.

The anatomical and radiological evaluation of the Vidian canal on cone-beam computed tomography images.

INTRODUCTION: The aim of this study is to explore the anatomy of the Vidian nerve to elucidate the appropriate surgical approach based on preoperative cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: The Vidian canal and its surrounding structures were morphometrically evaluated retrospectively in CBCT images of 400 cases by the Planmeca Romexis program. The types of the Vidian canal were determined and seven parameters were measured from the images. RESULTS: Three types of the Vidian canal according to the relationship with the sphenoid bone were found as follows: the Vidian canal totally protruded into the sphenoid sinus (19.75%), partially protruded into sphenoid sinus (44.37%) and embedded inside bony tissue of the body of sphenoid bone (35.87%). The position of the Vidian canal was medial (34.62%), on the same line (55.12%) and lateral (10.25%) to the medial plate of the pterygoid process. The distance between the Vidian canal and the vomerine crest, the mid-sagittal plane, the round foramen, the palatovaginal canal, and the superior wall of the sphenoid sinus, the length of the Vidian canal and the angle between the Vidian canal and the sagittal plane was found to be 16.69 ± 2.14, 13.80 ± 2.00, 8.88 ± 1.60, 5.83 ± 1.37, 23.98 ± 2.68, 13.29 ± 1.71 mm and 25.78° ± 3.68° in males, 14.62 ± 1.66, 11.43 ± 1.28, 8.51 ± 1.63, 5.78 ± 0.57, 22.37 ± 2.07, 12.91 ± 1.26 mm and 23.43° ± 3.07° in females, respectively. CONCLUSIONS: Our results may assist with proper treatment for surgical procedures around the Vidian canal with a high success rate and minimal complications. Therefore, the results obtained in this study contribute to the literature.

The anatomic analysis of the vidian canal and the surrounding structures concerning vidian neurectomy using computed tomography scans.

INTRODUCTION: The type of endoscopic approach chosen for vidian neurectomy can be specified by evaluating the vidian canal and the surrounding sphenoid sinus structures. OBJECTIVE: The variations and morphometry of the vidian canal were investigated, focusing on the functional correlations between them which are crucial anatomical landmarks for preoperative planning. METHODS: This study was performed using paranasal multidetector computed tomography images that were obtained with a section thickening of 0.625mm of 250 adults. RESULTS: The distributions of 500 vidian canal variants were categorized as follows; Type 1, within the sphenoid corpus (55.6%); Type 2, partially protruding into the sphenoid sinus (34.8%); Type 3, within the sphenoid sinus (9.6%). The pneumatization of the pterygoid process is mostly seen in vidian canal Type 2 (72.4%) and Type 3 (95.8%) (p<0.001). The mean distances from the vidian canal to the foramen rotundum and the palatovaginal canal were greater in the vidian canal Type 2 and 3 with the pterygoid process pneumatization (p<0.001). The prevalence of the intrasphenoid septum between the vidian canal and the vomerine crest and lateral attachment which ending on carotid prominence were much higher in vidian canal Type 3 than other types (p<0.001). The mean angle between the posterior end of the middle turbinate and the lateral margin of the anterior opening of the vidian canal was measured as 33.05±7.71°. CONCLUSIONS: Preoperative radiologic analysis of the vidian canal and the surrounding structures will allow surgeons to choose an appropriate endoscopic approach to ensure predictable postoperative outcomes.

Utility of the Vidian Canal in Endoscopic Skull Base Surgery: Detailed Anatomy and Relationship to the Internal Carotid Artery.

OBJECTIVE: To investigate key anatomic features of the vidian canal that have a critical role in planning and performing endoscopic skull base surgeries. METHODS: We reviewed skull base computed tomographic images of 640 consecutive subjects. Studies were analyzed in axial, coronal and sagittal planes. RESULTS: The mean (±SD) length of the vidian canal was 15.4 ± 2.0 mm in female subjects and 16.6 ± 1.7 mm in male subjects, and the difference between genders was statistically significant (P < 0.001). The most common rostral-caudal course of the vidian canal was medial to lateral and was followed by the straight course, tortuous course, and lateral-to-medial course. The frequency of pneumatization pattern from most common to least common was types 0, III, II and I. Of 342 evaluated sides, the vidian canal was located below the level of the anterior genu of petrous ICA in 303 (89%) sides, at same level with the anterior genu of petrous ICA in twenty-five(7%) sides, and above the level of the anterior genu of petrous ICA in fourteen(4.1%) sides. CONCLUSIONS: A variety of previously undefined features of the vidian canal that can alter the course of surgical procedure were defined. The position of the vidian canal with respect to the petrous internal carotid artery (ICA) was extensively described. From a surgical standpoint, a working room inferior and medial to the vidian canal might not always be a safe approach, because the vidian canal could be located superior to the level of the anterior genu of petrous ICA according to our findings in the present study.