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.

Relation between volume of sphenoid sinuses and protrusion of Vidian nerve: possible applications to Vidian neurectomy.

PURPOSE: Vidian neurectomy is a surgical procedure applied to different pathological conditions, including chronic rhinitis and sphenopalatine neuralgia. The choice of the correct surgical approach depends upon the possible protrusion of Vidian nerve into the sphenoid sinuses. The present study analyzes the possible relationship between protrusion of Vidian nerve and volume of sphenoid sinuses. METHODS: In total, 320 maxillofacial CT-scans were retrospectively assessed. Subjects equally divided among males and females (age range 18-94 years) were divided into three groups according to the profile of Vidian nerve protrusion: type 1: Vidian nerve inside the sphenoid corpus; type 2: partially protruding into the sphenoid sinus; and type 3: entirely protruding into the sphenoid sinus through a stalk. Volume of sphenoid sinuses was extracted through the ITK-SNAP-free software and automatically calculated. Possible statistically significant differences in prevalence of the three types between males and females were assessed through Chi-squared test (p < 0.05). Differences in volume of sphenoid sinuses in subjects included within the three types were assessed through one-way ANOVA test (p < 0.05), separately for males and females. RESULTS: Type 2 was the most prevalent (46.5%), followed by type 1 (38.8%) and type 3 (14.7%), without significant differences according to sex (p > 0.05). Volume significantly increased passing from type 1 to type 3 both in males (p < 0.01) and in females (p < 0.01). CONCLUSIONS: The results prove the existence of a strict relationship between sphenoid sinuses pneumatization and protrusion of the Vidian canal and give a contribution to the knowledge of this important anatomical variant in endoscopic surgery.

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 pterygopalatine fossa: morphometric CT study with clinical implications.

PURPOSE: The pterygopalatine fossa is a deep viscerocranial space containing the maxillary artery and nerve, the pterygopalatine ganglion, and the nerve of the pterygoid canal (vidian nerve). The endoscopic approach to this area relies on adequate preoperative imaging, such as computed tomography (CT). The aim was to determine the morphometric characteristics of the pterygopalatine fossa and its communications, including several previously unpublished measurements. METHODS: 100 CT scans (56 male and 44 female patients) were analyzed. The axial, coronal, and sagittal slices, together with the three-dimensional reconstructions, were used in the study. RESULTS: The central diameter and the length of the foramen rotundum, the vertical diameter and the length of the pterygoid (vidian) canal, and the diameter of the sphenopalatine foramen were significantly larger in men. The central diameters of the foramen rotundum and the vidian canal were significantly smaller than their anterior and posterior transverse diameters. The vidian canal length of 12.1 mm indicates the presence of the type 3 VC with a sensitivity of 83% and a specificity of 85%. CONCLUSION: Several new descriptions of the pterygopalatine fossa are presented here (such as the angle between the sphenopalatine foramen and the vidian canal, a new aspect in the understanding of the FR, and the distance between the posterior wall of the maxillary sinus to the vidian canal and the foramen rotundum), which might prove useful in the comprehension of the anatomy of the pterygopalatine fossa.

Anatomical study of pterygoid canal (PC) and palatovaginal canal (PVC) in endoscopic trans-sphenoidal approach.

PURPOSE: The primary purpose of our work was to make anatomical measurements of pterygoid canal (PC) and palatovaginal canal (PVC). The secondary goal was to locate the two structures based on the landmarks in the trans-sphenoidal surgery and draw a safe corridor of fenestration in the bottom of sphenoid sinus during surgical procedure to sphenopalatine region. MATERIALS AND METHODS: Computed tomographic angiography (CTA) images of PC, PVC and sphenoid sinus in 200 adults were reviewed. Multiplanar reconstruction of the CT images was performed, and the anatomical features of the PC and PVC were studied in the coronal, sagittal, and axial planes. The length, diameter and direction of PC and PVC were measured in the plane through or perpendicular to them. The anterior and posterior opening of PC and PVC were identified by the surgical landmarks such as the middle lowest point of sellar floor, the sagittal midline and the bottom of the sphenoid sinus. RESULT: Both PC and PVC can be found and identified easily on CTA image, the shape and size of the PC and PVC were in agreement with those retrieved from previous literatures, the position of them can be located by the anatomical landmarks in sphenoid sinus. CONCLUSION: Knowing the anatomical features of PC and PVC and their location based on the anatomical landmarks are helpful to the endoscopic trans-sphenoidal surgery. These data in our study will provide surgeons a better understanding of PC and PVC and their relationship to sphenoid sinus. Notably, it will not help the surgeons to avoid injuring neurovascular structures as well as provided supportive information for the choice of the appropriate endoscopic equipment.

[Imaging study of anatomical parameters related to pterygoid canal neurotomy].

Objective:Measuring the important anatomic parameters related to vidian neurectomy to locate the vidian nerve accurately and prevent the surgical complications. Methods:High resolution CT（HRCT） was used to measure the distance parameters between the important anatomic landmarks in 50 patients （100 sides） with chronic rhinosinusitis, sinus cyst or allergic rhinitis et al. The distance from the posterior opening of the palatovaginal canal to the upper edge of the sphenoidal process of palatine bone, the upper edge of the sphenoidal process of palatine bone to the external opening of the vidian canal, the external opening of the vidian canal to the greater palatine canal, and the external opening of the vidian canal to the foramen rotundus were measured. Results:The posterior opening of the palatovaginal canal, the upper edge of the sphenoidal process of palatine bone, the external opening of the vidian canal, the greater palatine canal, and the foramen rotundum are of great value in locating vidain nerve and preventing surgical complications. The distance from the posterior opening of the palatovaginal canal to the upper edge of the sphenoidal process of palatine bone, the upper edge of the sphenoidal process of palatine bone to the external opening of the vidian canal, the external opening of the vidian canal to the greater palatine canal, and the external opening of the vidian canal to the foramen rotundus were（12.46±1.19） mm, （3.23±0.36） mm, （6.09±0.75） mm and（7.6±1.16） mm respectively. Conclusion:HRCT can be used as a powerful tool for preoperative localization of the external pterygoid nerve orifice and its related important anatomical landmarks, and the preoperative distance parameters obtained are valuable for intraoperative localization of the pterygoid nerve to prevent the occurrence of complications.

[Clinical observation of highly selective vidian neurectomy guided by the palatovaginal canal].

Objective:Summarize the safety and feasibility of highly selective vidian neurectomy guided by the palatovaginal canal. Methods:Hypothermal plasma surgery was performed on 53 patients with perennial allergic rhinitis （PAR）. Remove the soft tissue covering the anterior wall of the sphenoid process of palatine bone using the Coblation system. Find the palatovaginal canal and cut off the neurovascular bundle in the palatovaginal canal. Expose the anterior orifice of the vidian canal and cut off the vidian nerve. Results:53 PAR patients have conducted the novel vidian neurectomy without sphenopalatine artery trunk damage. No secondary hemorrhage and hard palate numbness happened. The symptoms of nasal obstruction, sneeze, nasal discharge, and rhinocnesmus were relieved significantly. Conclusion:The simple and safe approach of highly selective vidian neurectomy guided by the palatovaginal canal provides an alternative surgical option for clinicians.

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.

Morphological study of the pterygoid canal with high-resolution CT.

The purpose of our study was to accurately visualize and measure the normal anatomy and size of the pterygoid canal with thin-section (0.5 mm), high-resolution computed tomography (HRCT) as well as multiplanar reconstruction (MPR) and curved planar reconstruction (CPR) technologies to obtain credible and comprehensive information for clinical management. Both axial HRCT and MPR images of the pterygopalatine fossa were obtained in 167 normal adult subjects, who exhibited variable positions of pterygoid canal relative to the sphenoid sinus floor and cavity. The morphology and size of the pterygoid canal was observed and measured, respectively. All pterygoid canals (100%, 334/334) were well delineated on HRCT images. Statistical analyses showed no significant difference between the mean length of the left (12.6 ± 2.3 mm) and right pterygoid canals (12.5 ± 2.9 mm) (P = 0.405). The mean diameter of anterior, median and posterior opening of the left and right pterygoid canals exhibited no significant differences (all P > 0.05); the bilateral median opening possessed the smallest diameter (P < 0.001). Submillimeter, thin-section HRCT scan and appropriate postprocessing reconstruction technologies could clearly visualize the morphologic features of the pterygoid canal and adjacent structures, which may be helpful for making diagnostic and therapeutic decisions.

Simultaneous observation and discrimination of palatovaginal and vomerovaginal canals by transverse CT.

This study is to palatovaginal canal and vomerovaginal canal identify by computed tomography (CT) transverse imaging and are often mislabeled by investigators. We used a probe guide method in skull specimens to establish the CT imaging features of the two canals. We also used endoscopy to look deeply into the inside structure of them. Finally, CT images of patients were used to confirm our findings. Based on our results using 20 skull specimens and 70 patients, we established a simple method that can be used to identify the two canals on CT transverse imaging. In the transverse images of skull specimens and of patients, the frequency of simultaneous observation of the two canals was 72.5% and 70.71%. We also identified several mislabeled images of the palatovaginal and vomerovaginal canals in published papers. In summary, we found that the two canals could be observed and distinguished by transverse CT imaging. Furthermore, we established a method that could distinguish them. In conclusion, our findings will have a great impact not only on the accurate identification of the pterygoid canals but also on the early detection of tumor metastasis and palatine artery embolization.