Protrusion Of Internal Carotid Artery Research Articles

Anatomical variations of sphenoid sinus in terms of volume and protrusions of optic nerve/internal carotid artery in a subgroup of Pakistani population.

To compare the volume of sphenoid sinus with protrusions of optic nerve and internal carotid artery in both males and females. The cross-sectional study was conducted from October 2020 to February 2021 at the Radiology Department of Dow University of Health Sciences, Karachi, and comprised males and females aged 20-60 years having no sphenoid sinus bony abnormality. Sphenoid volume and optic nerve and internal carotid artery protrusions were examined in the computed tomography scans of the paranasal sinus. Based on the protrusions, the scan findings were split into four groups: Group 1 had no protrusion, Group 2 had optic nerve protrusion, Group 3 had internal carotid artery protrusion, and Group 4 had protrusions of both the optic nerve and the internal carotid artery. Data was analysed using GraphPad Prism 9. Of the 300 subjects, 171(57%) were males and 129(43%) were females. The overall mean age was 39.27±10.9 years. There were 147(49%) subjects in group 4, followed by 72(24%) in group 3, 42(14%) in group 2 and 39(13%) in group 1. Statistically significant difference was observed between sphenoid volume across the study groups for both male and female subjects (p<0.001). There was significant relationship between internal carotid artery and optic nerve protrusions and sphenoid volume.

Unravelling the Complex Relationship Between Frontal Sinus Pneumatization and Paranasal Sinus Anatomical Variants: Insights from CT Imaging.

The aim of this study was to analyse the relationship between frontal sinus pneumatization and its effect on various variations of paranasal sinuses on paranasal sinus CT scan. A total number of 100 patients (51 males, 49 females) were included in this study. Patients were divided into three groups on the basis of their frontal sinus pneumatization extent on paranasal sinus CT as Type 1 pneumatization (aplasia and hypoplasia), Type 2 pneumatization (medium) and Type 3 pneumatization (hyperplasia). The prevalence of various variations like pneumatization of upper and middle turbinate, presence of agger nasi, Haller and Onodi cell, maxillary sinus hypoplasia, extent of sphenoid sinus pneumatization, pneumatization of anterior clinoid process, pterygoid process and greater wing of sphenoid sinus, dehiscence and protrusion of internal carotid artery and optic nerve types were ascertained and compared within each group. The prevalence of Onodi cell, anterior clinoid process and greater wing of sphenoid pneumatization and optic nerves type 3 and 4 were higher in Type 3 frontal sinus pneumatization group as compared with other groups. Excessive pneumatization of frontal sinus has various effects on paranasal sinus variations. Surgeons dealing with endoscopic sinus surgery, maxillofacial and skull base surgery must be vigilant of association between these variations preoperatively for avoiding complications.

Evaluation of the relationship between sphenoid sinus morphology and area and volume by computed tomography.

The aim of this study is to investigate the effect of sphenoid sinus pneumatization types, Onodi cell (OC), internal carotid artery (ICA), optic nerve (ON) on sinus volume and area on computed tomography (CT) images. The CT images of 150 patients were evaluated. Sphenoid sinus pneumatization types, OC prevalence, protrusion and dehiscence of ICA and ON, the volume and area were evaluated. The sinus volume and area were statistically higher in patients with bilateral protrusion of ICA and ON then patients without protrusion of ICA and ON. The mean volume and area of sinus were 9949.4 ± 351.0mm3 and 4570.9 ± 1604.9mm2, respectively. The volume and area of sphenoid sinus did not differ significantly between groups with and without OC. The postsellar b type sphenoid sinus had the highest volume, while conchal type has the least volume. Bilateral protrusion and dehiscence of ICA and bilateral protrusion of ON caused a significant increase in the sphenoid sinus volume and area. The presence of ICA and ON, the pneumatization of the sinus is an anatomical structure that can affect the sinus volume and area. Before the operation, three-dimensional evaluation should be performed to determine whether these structures are bilateral/unilateral and it should be remembered that the sinus volume and area can change.

Association of accessory sphenoidal septum with protrusions of sphenoid sinus.

Accessory sphenoidal septum (ASS) is a septal variation that exists in addition to the primary septum of the sphenoid sinus and can be found in or near anatomically essential structures. This study aimed to investigate the relationships between protrusions of vital structures around the sphenoid sinus and the ASSs. This cross-sectional retrospective study is based on the analysis of CBCT scans of 314 patients in axial, coronal, and sagittal planes with 0.2-0.3 slice thicknesses. Optic nerve (ON), internal carotid artery (ICA), both ON and ICA, maxillary nerve (MN), vidian canal (VN) and ASSs were detected, and the relationship between protrusions of these vital anatomical structures and ASS was evaluated. Statistically significant relationship was observed between the right Type 1 ON protrusion (p < 0.05) and left Type 1 ON protrusion (p = 0.001); left Type 3 ON protrusion (p < 0.05); right Type 4 ON protrusion (p < 0.05) and ASS. Statistically significant relationship was also observed between the right ICA protrusion and ASS (p < 0.05). The right Type 1 VN protrusion (p = 0.001); left Type 2 VN protrusion (p < 0.001); right and left Type 3 VN protrusions (p < 0.001) were found to be significantly associated with the ASS. ASSs have significant associations with some protrusions, and they tend to cause potentially severe complications in endoscopic sinus surgery. This variability requires a comprehensive understanding of regional sphenoid sinus anatomy with detailed three-dimensional tomographic imaging.

A comparative study of paranasal sinus and nasal cavity anatomic variations between the Polish and Turkish Cypriot Population with CBCT

BackgroundGenetic and environmental factors especially climatic conditions are thought to influence the shape and size of the paranasal sinuses and anatomic variations may create both a diagnostic and therapeutic challenge. However, no study has been published about the climatic adaptation of the paranasal sinus region in different populations. This study aimed to compare the prevalence of anatomical variants in the paranasal sinus and nasal cavity using Cone-Beam Computed Tomography (CBCT) between Polish and Turkish Cypriot populations.MethodsThe material consisted of volumes acquired utilizing Galileos (Sirona, Germany) as well as Newtom 3G (QR Verona, Newtom, Italy) CBCT units. There were examined 356 Polish and 359 Turkish Cypriot patients in whom paranasal sinuses were included in the field of view. Paranasal sinus anatomic variations were assessed in both populations.ResultsIn the Polish population, the most common anatomic variation was septum deviation followed by the Agger nasi cell and concha bullosa with a prevalence of 87.7%, 83.2%, and 54.8% respectively. For the Turkish Cypriot population, the most common anatomic variation was Agger nasi cell followed by concha bullosa and supraorbital ethmoid cells with a prevalence of 81.6%, 68%, and 57.8% respectively. Many anatomic variations were found to show substantial differences among both populations. Incidence rates of hyperpneumatization of the frontal sinus, septum pneumatization, supraorbital ethmoid cells, concha bullosa, uncinate bulla, and internal carotid artery protrusion into the sphenoid sinus were significantly higher in the Turkish Cypriot group, while the incidence of Haller cell, frontal sinus hypoplasia, maxillary sinus hypoplasia, ethmomaxillary sinus, sphenomaxillary plate, and septum deviation were significantly higher in Polish population.ConclusionAccording to the Köppen-Geiger world climatic map, the climate is warmer and drier in Turkish Cypriote populations than in the Polish population. These climatic differences influence the paranasal sinus variations between the Turkish Cypriot and Polish populations that must be taken into account by rhinologic surgeons especially when performing frontal and sphenoid sinus surgery.

Clinico-anatomical relationships between the internal carotid artery and sphenoid sinus usingcomputed tomography

Unexpected and sometimes inexplicable massive haemorrhage arising from intracranial injury to the internal carotid artery (ICA) is a life- threatening complication of endoscopic transsphenoidal skull base surgeries. Pre-interventional computed tomography (CT) assessment of the anatomical relationships between the ICA and the sphenoid sinus is necessary to understand and prevent this complication. The aim of this study was to determine the normal anatomical variations between the sphenoid sinus and internal carotid artery using CT and evaluate their relationship with sinus dimensions. The CT scans of 323 sphenoid sinuses of patients aged 18 to 80 years were retrospectively studied. The images were taken with a GE Bright Speed Multi detector Helical CT Scanner and viewed using the Digital Imaging and Communication in Medicine (DICOM) viewer. The anteroposterior, craniocaudal and transverse diameters were measured and used to determine sinus volume. Protrusion of the ICA into the sinus cavity, dehiscence, and presence of septal ttachments to the sinus walls bordering the ICA were studied. The prevalence of ICA protrusion, dehiscence of sinus wall, and septal attachment were 28.48%, 17.34% and 13.93% respectively. There was a statistically significant relationship between protrusion of ICA and the anteroposterior and transverse sinus diameters. The relationship between dehiscence of the wall over the ICA and sinus volume as well as the transverse diameter was statistically significant. A careful CT identification of these normal but potentially dangerous variations between the ICA and the wall of the sphenoid sinus prior to surgery is essential for a safe cranial base endoscopic transsphenoidal procedure.

Evaluation of anatomical variants of sphenoid sinus by multidetector computed tomography

Background: Para nasal sinuses are air-filled cavities present in facial bones. Sinusitis is a common medical problem affecting millions of people annually. CT screening of paranasal sinuses has the advantages of showing bony details and good soft tissue outlines. CT is valuable in the identification of variations in pneumatisation of sphenoid sinuses and characterization of sphenoid variations prior to FESS and trans-sphenoidal surgeries. Materials and Methods: This was a cross-sectional study conducted at Dr. PSIMS & RF, Chinnavutapalli. This study was done on SIEMENS SOMATOM EMOTION 16 slice spiral CT machine. We included a total of 100 patients clinically diagnosed with chronic sinusitis, who were referred for CT scan of PNS in our hospital. Results: Out of 100 patients, 52 males and 48 females. Most of the patients were in the 20-30 years age group comprising 55% of the study population. Presellar type of pneumatisation found in (83%), Postsellar type of pneumatisation (11%). Pneumatisation of pterygoid process (42%), anterior clinoid process (28%), greater wing of sphenoid (22%). Bilateral protrusion of internal carotid artery (19 cases), right side (5 cases) and on left side (3 cases). Protrusion of optic nerve noted in 21 cases, among these 14 bilaterally, (4) right N and (3) left side, maxillary nerve protrusion (16 cases), among these 8 (bilaterally), (5) right and (3) left side, Vidian nerve protrusion (20 cases), among these (8) bilaterally, (7) right and (5) left side. Conclusion: Computed Tomography plays an important role in visualization of variation in sphenoid sinus and its pneumatisation patterns and has re-emphasized the concept that variations especially in the sphenoid sinus region is the key factor in the causation of accidental damage to vital structures like ICA, Optic nerve, Maxillary nerve and Vidian nerve.

Cone Beam Computed Tomography Analysis of Sphenoid Sinus Pneumatization and Relationship with Neurovascular Structures.

The sphenoid sinus is considered as the most variable pneumatized structure of the skull. The aim of the present study was to determine the prevalence of the Onodi cell as well as to evaluate the relationship between the sphenoid sinus type of pneumatization and the presence of surrounding neurovascular protrusion using cone beam computed tomography (CBCT). The CBCT images of 500 patients/996 sides [203 males (40.6%) and 297 females (59.4%)] were analyzed in this study. The type of sphenoid sinus pneumatization, prevalence of internal carotid artery (ICA) and optic nerve (ON) protrusion and dehiscence, and also the frequency of Onodi cell were assessed. The percentages of the conchal, presellar, sellar, postsellar (a), and postsellar (b) types of pneumatization were 1%, 11.5%, 35.5%, 38.9%, and 13.1%, respectively. The more the sphenoid sinuses pneumatized, the greater the frequency of ON and ICA protrusion and dehiscence of their wall to the sinus. The prevalence of Onodi cell was 38.8%. A significant correlation was found between ON dehiscence and the presence of Onodi cells. The present study demonstrated a significant relationship between the sinus type and frequency of neurovascular protrusions. Therefore, the sphenoid sinus extent of pneumatization might be useful in predicting the risk of iatrogenic damage to the surrounding structures.

Variations in the Anatomy of Sphenoid Sinus: A Computed Tomography Investigation

Aims: The sphenoid sinus is surrounded by many neurovascular structures which are very vulnerable to intrasphenoid sinus surgeries. The purpose of this study is to investigate the variation of sphenoid sinus structure by CT scan imaging.&#x0D; Methodology: This is a retrospective study of 3D images of a paranasal sinus in 129 cases. In this study, three-way metering of the sphenoid sinus, additional septum, pneumatization of the period process (PP), anterior clinoid process (ACP) and greater wing of sphenoid and protrusion and dehiscence of adjacent structures will be assessed.&#x0D; Results: Protrusion of internal carotid artery (ICA), a vidian nerve, maxillary nerve (V2) and optical canal were seen respectively 50.4%, 57.36%, 62.5% and 54.3% but dehiscence of this structure was seen 8.5%, 7%, 3.9% and 6.2%. penumtazition of PP, ACP and greater wing of sphenoid were seen 96.87%, 43.9% and 41.1%. Additional septum also is seen in 76% of the population.&#x0D; Conclusion: This study demonstrates numerous variations in sphenoid sinus structure. Some of the variations cause many problems during intrasphenoidal surgery. Therefore, physicians should evaluate patients completely before surgery.

Relationship between sphenoid sinus volume and protrusion of internal carotid artery and optic nerve: a 3D segmentation study on maxillofacial CT-scans

Anatomy of sphenoid sinuses has acquired a growing importance with the diffusion of transsphenoidal surgical procedures. A common risk in these practices is the damage of internal carotid artery (ICA) and optic nerve (ON), which may protrude into the sphenoid air cavities. This study aims at analysing the relationships between sphenoid sinuses volume and protrusion of ICA and ON. 260 head CT-scans were retrospectively analysed (equally divided among males and females, age range 20-92years). Volume was segmented through ITK-SNAP software. In addition, the subjects were classified into four groups: no protrusion of any structure (group 1), protrusion of ICA (group 2), protrusion of ON (group 3), protrusion of both ICA and ON (group 4). Possible statistically significant differences in prevalence of the four groups according to gender were assessed through Chi-squared test (p < 0.05). Differences in volume between the four groups were assessed through one-way ANOVA test (p < 0.05), separately for males and females. Group 1 was the most frequent (40.0%), followed by group 4 (27.7%) and group 2 (18.5%), without any difference according to gender. For what concerns volume, cases of ICA and concomitant ICA + ON protrusion had significantly larger sinuses, whereas isolated ON protrusion did not modify sinus volume. Results show that protrusion of ICA is positively related with the volume of sphenoid sinuses, whereas the same relation was not verified for ON: surgeons should accurately consider possible ON protrusion in each case, as it may occur independently from sphenoid sinuses volume.

The effect of frontal sinus pneumatization on anatomic variants of paranasal sinuses.

The aim of this study is to determine the effect of frontal sinus pneumatization on various variations of paranasal sinuses on maxillofacial CT. A total number of 120 patients (62 females, 58 males) were included in this study. Patients were divided into three groups regarding their frontal sinus pneumatization extent on paranasal sinus CT as Type 1 pneumatization (aplasia and hypoplasia), Type 2 pneumatization (medium) and Type 3 pneumatization (hyperplasia). The prevalence of various variations on paranasal sinus CT like pneumatization of upper and middle concha, presence of agger nasi, Haller and Onodi cell, maxillary sinus and sphenoid sinus hypoplasia, pneumatization of anterior clinoid process, pterygoid process and greater wing of sphenoid sinus, dehiscence and protrusion of internal carotid artery and optic nerve and vidian canal types were ascertained and compared within each group. The prevalence of upper and middle concha pneumatization, Haller cell, pneumatization of anterior clinoid process, pterygoid process and greater wing of sphenoid and internal carotid artery dehiscence and protrusion was higher in Type 3 group compared with other groups. Excessive pneumatization of frontal sinus has various effects on paranasal sinus variations at maxillofacial CT. Surgeons dealing with endoscopic sinus surgery, maxillofacial and skull base surgery must be vigilant of association between certain variations when analyzing CT scan preoperatively for avoiding complications.

Sphenoid Sinus Pneumatization, Septation, and the Internal Carotid Artery: A Computed Tomography Study.

Background:The air spaces of the nasal cavity and the sphenoid sinus (SS) constitute a convenient corridor to access lesions of the skull base using the endoscopic endonasal transsphenoidal approach (EETA). Safe EETA depends on the SS and skull base anatomy of the patient. Individual variations exist in the degree and pattern of SS pneumatization. This study aims to examine the variations in SS pneumatization, the inter-sphenoid septum (ISS), and their relationship with the internal carotid artery (ICA) among adult Nigerians.Materials and Methods:We reviewed computerized tomography (CT) images of 320 adult patients that had imaging for various indications. This excluded those with traumatic, inflammatory, or neoplastic process that may alter anatomical landmarks. The images were evaluated for the types of SS pneumatization, number and insertion of ISS, and the protrusion of ICA into the sinus cavity.Results:Prevalence of SS pneumatization types: 1.9% conchal, 1.2% presellar, 56.6% sellar, and 40.2% postsellar. The lateral extension of SS occurred into the pterygoid in 138 patients (45.1%), greater wing 112 (35%), lesser wing 37 (11.6%), the full lateral type was seen in 97 (30.3%) patients. One ISS occurred in 150 (46.9%) patients, 162 (50.6%) had multiple, and 8 (2.5%) had none. ISS insertion into ICA bony covering occurred in 101 (31.6%) patients, whereas protrusion of ICA into SS cavity occurred in 110 (34.4%) patients.Conclusion:Variations of the SS, ISS, and ICA anatomy are present among native Africans. Detailed imaging evaluation of each patient is considered for EETA is mandatory.

Anatomical variants of surgically important landmarks in the sphenoid sinus: a radiologic study in Southeast Asian patients.

Failure of a surgeon to understand the local variations of the anatomical landmarks of the sphenoid sinus is a potential risk factor to cause damage to the optic nerve (ON) or internal carotid artery (ICA) that lies on the walls of the sphenoid sinus. The aim of this study was to identify the anatomical variants of the sphenoid sinus and its related surrounding structures among the Southeast Asian (SEA) population, based on computed tomography (CT) scans. This cross-sectional study analyzed 300 CT scans of the brain, paranasal sinuses (PNS), and head and neck (H&N) at a tertiary referral centre in Malaysia utilizing the Osirix software. The images were reconstructed into 1 mm cuts on bone window. Demographic details and scan findings were documented in a standardized data collection sheet. The rates of ON dehiscence, ICA dehiscence and ICA protrusion in the SEA population were 7.0, 3.0 and 10.0 %, respectively. The rate of ON protrusion was 2.3 %. There was no statistically significant relationship (p > 0.05) noted on Chi-square test, between anterior clinoid process (ACP) pneumatization and ON protrusion. The rate of Onodi cells in our population was 14.3 %. The average vertical distance of the ostia from the roof of the posterior choanae was 1.42 cm (±0.32). The horizontal distance of the ostia from the anterior end of the superior turbinate was 1.58 cm (±0.41) and the oblique distance of the ostia from the anterior nasal spine was 5.35 cm (±0.48). Independent t tests showed that there is a statistically significant difference between the means of each of these parameters (p < 0.001) and their international averages. The rate of ON protrusion is lower in the SEA population, whereas the rates of ON dehiscence, ICA dehiscence and ICA protrusion fall within the range of international averages. In our population, ACP pneumatization is not related to ON protrusion. The distance of the ostia from given landmarks was significantly shorter than in other studies.

Study of the relationship between sphenoid sinus volume and protrusions in the sphenoid sinus

The relationship between the volume of sphenoid sinus (SS) and the prevalence of internal carotid artery (ICA) and optic nerve (ON) protrusions in the SS was studied by using high-resolution CT imaging. The ICA and ON protrusions in SS were observed in randomly selected normal head CT scanning images from 350 adult subjects. Ac-cording to the incidence of ICA protrusion, three groups were divided into no ICA protrusion (70.75%), unilateral protrusion (8.68%) and bi-lateral protrusions (20.57%). The ON protrusion accounted for 16% in 350 subjects and accom-panied absolutely with ICA protrusion, but ICA protrusion appeared without accompanying with ON protrusion. The SS volume depended upon the protrusions in it and showed statistical dif-ferences, without ICA protrusion, the smallest size (11.16 ± 1.60) cm3; the unilateral protrusion, medium size (14.20 ± 1.80) cm3 and the bilateral protrusion, the largest size (25.03 ± 2.21) cm3. By observing 3D reconstructed models of ON and SS, we found ON was adjacent to SS (46%) and to posterior ethmoid sinuses (44%). The current study indicates that SS volume is varied with numbers of the protrusions and that ON location varies with the pneumatization of SS. Our results provide an anatomical basis to the surgeries for SS and its surrounding structures.

High-Resolution Computed Tomography Analysis of Variations of the Sphenoid Sinus

Purpose The sphenoid sinus is a complex structure with key variations that are important for endoscopic parasellar approaches. In this study, high-resolution computed tomography (HRCT) scans were analyzed for the frequency of these variations. Methods A retrospective radiographic analysis was conducted on patients undergoing HRCT between July 2008 and September 2010. Results Sphenoid sinus pneumatization was defined as conchal, presellar, sellar, and postsellar based on pneumatization relative to the anterior and posterior face of the sella. The distribution ranged from 1.8%, 7.3%, 47.6%, and 43.3%, respectively. We found a greater preponderance of sellar and postsellar variation than previously reported. No differences were found in regard to age, gender, and ethnicity (African American, Caucasian, Asian, and Hispanic) (p > 0.05). The prevalence of optic nerve, maxillary nerve, and internal carotid artery protrusion was 26.1%, 25.9%, and 28.2%, respectively, and dehiscence was 2.1%, 7.4%, and 2.9%, respectively. Accessory septae were present in 43.5% of cases. A lateral recess was identified in 72.4% and clinoid pneumatization in 20% of patients. Conclusion This study demonstrates a greater prevalence of sphenoid sinus pneumatization and variations than previously reported. This has important implications in terms of preparation and anticipation of possible variations to avoid complications.

Role of magnetic resonance imaging in evaluating sphenoid sinus and internal carotid artery

This study aimed to determine whether magnetic resonance imaging has a role in the evaluation of the sphenoid sinus and internal carotid artery. In addition, we aimed to establish reference measurements for the minimal distance between the internal carotid arteries. The sphenoid sinuses and neighbouring internal carotid arteries of 90 patients were evaluated using sagittal T1-weighted and axial and coronal T2-weighted magnetic resonance images. Sphenoid sinus pneumatisation was categorised as occipitosphenoidal (0 per cent), conchal (3.3 per cent), presellar (14.4 per cent) or sellar (82.2 per cent). The internal carotid artery protruded into the sphenoid sinus in 32.8 per cent, with a septum in 9.4 per cent. The incidence of sellar-type sphenoid sinus pneumatisation was higher in patients with protrusion of the internal carotid artery into the sphenoid sinus (p < 0.001). The incidence of presellar pneumatisation was higher in patients without internal carotid artery protrusion (p < 0.001). The minimal distance between the internal carotid arteries varied between 9.04 and 24.26 mm (mean, 15.94 mm). Magnetic resonance imaging can provide useful information about the sphenoid sinus and internal carotid artery, prior to endoscopic sphenoidotomy and trans-sphenoidal hypophysectomy.

Anatomical Variations of Neurovascular Structures Adjacent Sphenoid Sinus by using CT Scan

The aim of this research was to study of the relationship between anatomical variations of neurovascular structures adjacent sphenoid sinus with sex and position of appearance by using CT scan. In this retrospective study paranasal sinuses CT scan has been taken from 399 patients (210 male, 189 female) that referred to Imam Khomeini and Apadana Hospitals, Ahwaz, Iran. Furthermore, protrusion and dehiscence of Internal Carotid Artery (ICA), Maxillary Nerve (MN), Vidian Nerve (VN) and Optic Nerve (ON) into the sphenoid sinuses cavity have been investigated by using CT scan results. In 210 male patients the protrusion of interested variables were noticed as: ICA in 102 (48.5%) cases, ON in 80 (38%) cases, MN in 74 (35.5%) cases, and VN in 60 (28.5%) cases, respectively. Also in 189 female patients group the protrusion of ICA, ON, MN, VN were noticed in 65 (34.3%), 66 (34.9%), 62 (32.8%) and 43 (22.7%) cases, respectively. The statistical analysis show significant difference (p = 0.001) of protrusion of ICA between male and female groups. In 210 male patients the dehiscence of ICA, ON, MN, VN were noticed in 82 (39%), 60 (28.5%), 60 (28.5%) and 66 (31.4%) cases, respectively. Also in 189 female patients the dehiscence of interested variables were noticed as: ICA in 85 (44.9%), ON in 87 (46%), MN in 69 (36.5%), VN in 71 (37.5%) cases, respectively. The statistical analysis show significant difference (p = 0.03) of dehiscence of on variable in male and female groups. In order to increase the risk of intra-operative complications detailed preoperative investigation of neurovascular structures in sphenoid sinuses by use of CT scan images should be done properly.

Anatomic Variation of Sphenoid Sinus and Related Structures in Libyan Population: CT Scan Study

Background: Sphenoid sinus is the most inaccessible paranasal sinus, enclosed within the sphenoid bone and intimately related to numerous vital neural and vascular structures. Anatomic variation of the sphenoid sinus is well documented and may complicate surgery in such a place. Objective: To outline the surgically risky anatomic variants of the sphenoid sinus as well as the variable relationships between the sinus and related neurovascular structures, for the safe removal of intrasphenoid and pituitary lesions. Materials and Methods: We undertook a prospective review of 300 paranasal sinus CT scans of Libyan patients; coronal CT scans were obtained by special parameter techniques. We assessed pneumatization of pterygoid process (PP), anterior clinoid process (ACP), and greater wing of sphenoid (GWS); we also examined protrusion and dehiscence of internal carotid artery (ICA), optic nerve (ON), maxillary nerve (MN), and vidian nerve (VN) into the sphenoid sinus cavity. Results: Pneumatization of PP, ACP, and GWS were seen in 87 (29%), 46 (15.3%), and 60 patients (20%), respectively. Protrusion of ICA, ON, MN, and VN were noticed in 123 (41%), 107 (35.6%), 73 (24.3%), and 81 patients (27%), respectively; dehiscence of these structures was encountered in 90 (30%), 92 (30.6%), 39 (13%), and 111 patients (37%), respectively. Statistically, there was a highly significant association between ACP pneumatization and ICA protrusion, ACP pneumatization and ON protrusion, PP pneumatization and VN protrusion; and GWS pneumatization and MN protrusion (p-value < 0.001). Conclusion: The sphenoid sinus is highly variable; this variability necessitates a comprehensive understanding of the regional sphenoid sinus anatomy by a detailed CT scan sinus examination before surgery in and around the sinus. This study indicates the possibility of a racial anatomical variation of the sphenoid sinus in the Libyan population.

Anatomic Variation of Sphenoid Sinus and Related Structures in Libyan Population: CT Scan Study

BackgroundSphenoid sinus is the most inaccessible paranasal sinus, enclosed within the sphenoid bone and intimately related to numerous vital neural and vascular structures. Anatomic variation of the sphenoid sinus is well documented and may complicate surgery in such a place.ObjectiveTo outline the surgically risky anatomic variants of the sphenoid sinus as well as the variable relationships between the sinus and related neurovascular structures, for the safe removal of intrasphenoid and pituitary lesions.Materials and MethodsWe undertook a prospective review of 300 paranasal sinus CT scans of Libyan patients; coronal CT scans were obtained by special parameter techniques. We assessed pneumatization of pterygoid process (PP), anterior clinoid process (ACP), and greater wing of sphenoid (GWS); we also examined protrusion and dehiscence of internal carotid artery (ICA), optic nerve (ON), maxillary nerve (MN), and vidian nerve (VN) into the sphenoid sinus cavity.ResultsPneumatization of PP, ACP, and GWS were seen in 87 (29%), 46 (15.3%), and 60 patients (20%), respectively. Protrusion of ICA, ON, MN, and VN were noticed in 123 (41%), 107 (35.6%), 73 (24.3%), and 81 patients (27%), respectively; dehiscence of these structures was encountered in 90 (30%), 92 (30.6%), 39 (13%), and 111 patients (37%), respectively. Statistically, there was a highly significant association between ACP pneumatization and ICA protrusion, ACP pneumatization and ON protrusion, PP pneumatization and VN protrusion; and GWS pneumatization and MN protrusion (p-value < 0.001).ConclusionThe sphenoid sinus is highly variable; this variability necessitates a comprehensive understanding of the regional sphenoid sinus anatomy by a detailed CT scan sinus examination before surgery in and around the sinus. This study indicates the possibility of a racial anatomical variation of the sphenoid sinus in the Libyan population.

Variations of sphenoid and related structures.

The aim of this study was to delineate the precise relationship between the sphenoid sinus and internal carotid artery and the optic nerve, as well as to assess incidence of the anatomic variations of these structures. A review of 92 paranasal sinus tomographic scans was made for anatomic variations of the sphenoid sinus and related bony and neurovascular structures. Coronal and axial tomographic sections were obtained with 2.5-mm section thickness. We assessed the protrusion of the internal carotid artery (ICA) and the optic nerve (ON) into the sphenoid sinus, bone dehiscence of these structures, and pneumatization of the anterior clinoid process (ACP) and pterygoid recess (PR), as well as the variations of the sphenoid sinus septum. The protrusion of the ICA into the sphenoid sinus was found in 24 (26.1%) patients. An ON protrusion was present in 29 (31.5%) patients. Pneumatization of the PR was encountered in 27 (29.3%) patients. There was not a statistically significant relationship between the pneumatization of the PR and ICA protrusion into the sphenoid sinus (chi2 = 0.258, p = 0.168). A significant relationship between the ACP pneumatization and protrusion of the ON into the sphenoid sinus was found (chi2= 0.481,p = 0.007). Preoperative recognition of the anatomic variations by the radiologist is beneficial for identification of the limits of dissection. This is particularly important in the sphenoid sinus area where extensive pneumatization of the skull base bones may distort the anatomic configuration. Therefore, axial and coronal CT sections should always be obtained prior to any surgery in the sphenoid sinus area.