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Endoscopic intraoperative endo-sphenoidal view of the right sphenoid sinus. In this case, the carotid canal is dehiscent in the sinus cavity (*).
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Alongside the past development of endoscopic sinus surgery, knowledge about the anatomy of the sinuses has become crucial for surgeons. The sphenoid sinus is one of the most variable of all sinuses. Its relations to vital vascular and nervous elements make its approach a challenge for endoscopic surgeons. These relations include the internal caroti...
Context in source publication
Context 1
... internal carotid artery is the most medial element of the cavernous sinus, and it lies in direct relation to the lateral wall of the sphenoid sinus. Depending on the pneumatization of the sphenoid, the impression of the internal carotid artery may be barely noticeable or highly noticeable. Bulging of the internal carotid artery into the sphenoid sinus appears in 34-93% of cases, with apparent differences between races [10,[23][24][25]. In some cases, the thin bone usually covering the internal carotid artery is dehiscent (Figure 3), leaving the artery exposed to the sinus cavity. This has been reported in approximately 4% of cases [23][24][25]. It is vital that the surgeon is informed about these variations in order to avoid vital complications during surgery. The sphenoid sinuses are asymmetric cavities inside the sphenoid body separated by a bony septum. Literature describes this septum as being rarely situated on the median plane but very often deviated laterally to one side or the other. When this happens, it is common that it inserts on the carotid canal (Figure 4) or the optic canal [10,26]. More often than not, the sphenoid cavity is divided by more than one septa. Multiple intersinus septae or crests were found in 80% of cases according to Sareen D et al. (2005) [10]. According to FernandezMiranda JC et al. (2009), at least one of the septa is inserted on the carotid canal in 87% of cases [26]. These results indicate that extreme care should be taken intra- operatively before fracturing or removing these septa, being safer to leave them alone, if it is not absolutely necessary to take them down. ...
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Citations
... The body of sphenoid bone is gradually pneumatized by the sphenoidal sinus. Furthermore, the sella turcica, which is located on the concave superior surface of body of sphenoid bone, is an important area for the topography of neurovascular and endocrine structures 6,7 . ...
The aim of the present study was to examine the growth dynamics of the two ossification centers of the body of sphenoid bone in the human fetus, based on their linear, planar and volumetric parameters. The examinations were carried out on 37 human fetuses of both sexes aged 18–30 weeks of gestation, which had been preserved in 10% neutral formalin solution. Using CT, digital image analysis software, 3D reconstruction and statistical methods, we evaluated the size of the presphenoid and postsphenoid ossification centers. The presphenoid ossification center grew proportionately in sagittal diameter, projection surface area and volume, and logarithmically in transverse diameter. The postsphenoid ossification center increased logarithmically in sagittal diameter, transverse diameter and projection surface area, while its volumetric growth followed proportionately. The numerical findings of the presphenoid and postsphenoid ossification centers may be considered age-specific reference values of potential relevance in monitoring the normal fetal growth and screening for congenital disorders in the fetus. The obtained results may contribute to a better understanding of the growing fetal skeleton, bringing new numerical information regarding its diagnosis and development.
... Lateral walls, which are divided into the anterior orbital area and the posterior cranial area are directly adjacent to important structures such as the internal carotid artery, the optic nerve, and the cavernous sinus. Hence making sphenoid sinus surgeries quite intricate [5]. ...
... The sphenoid sinus is the most variable of the paranasal sinuses [1]. The degree and type of pneumatization varies with regard to the number and location of intra and intersinus septa, and its relationship with the neighboring surgical risk factors (II, III, IV, V, VI and Vidian nerves, Internal carotid artery (ICA) in the cavernous sinus and pituitary gland) [2]. ...
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 ± 351.0 mm3 and 4570.9 ± 1604.9 mm2, 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.
... On the other hand, the wide range between average values given in the previous articles may be owing to differences in study populations (e.g., age, sex, region, and side) or methods (CT, cone-beam computed tomography, digital caliper, etc.). 10,20,21,40,46,49,51 In CM-I group, three different types related to OS position relative to ACP were identified from the largest to the smallest as follows: Type D (64.60%) > Type C (31.70%) > Type E (3.70%). Similarly, three different types were identified in the control group as follows: Type D (64.40%) > Type E (27.80%) > Type C (7.80%). ...
Objective This study aimed to evaluate morphological features of the anterior clinoid process (ACP) and the optic strut (OS) in Chiari malformation Type I (CM-I).
Methods The study universe consisted of computed tomography images of 41 CM-I patients and 45 normal subjects. Comparison of the parameters for CM-I and the control group was performed with the Student's t-test. A “p < 0.05” was accepted as the significance level.
Results ACP length was smaller in CM-I than the control group (p < 0.001). In contrast to ACP length, ACP angle (p < 0.001), OS length (p = 0.022), and the distance between ACP and OS (p = 0.020) were found greater in CM-I in comparison to the control group (p < 0.05). ACP width (p = 0.233) and OS width (p = 0.376) were similar in both groups. ACP pneumatization in CM-I group was found as 12.20%, whereas in the control group as 8.90%. Two different types about the pneumatization were identified in CM-I group (Type 1: 4.9% and Type 2: 7.3%), whereas three different types in the control group (Type 1: 3.3%, Type 2: 4.4%, and Type 3: 1.1%). Relative to ACP, three different types about OS position were identified in CM-I group (Type C: 31.70%, Type D: 64.60%, and Type E: 3.70%) and the control group (Type C: 7.80%, Type D: 64.40%, and Type E: 27.80%).
Conclusions Shorter ACP, wide-angled ACP, longer OS, and more anteriorly located OS were found in CM-I group compared with the normal group. Our findings showed that the pneumatization of ACP was not affected by CM-I.
... (10) Therefore, those surgeons operating in the areas of sphenoid sinus should be well informed by the radiologist about variations occurring in this region of skull in order to avoid complications during surgery. (11)(12)(13) ...
Objective: To find out the frequency of protrusion of Internal Carotid artery in sphenoid sinus and dehiscence of carotid canal in a subset of Karachi population. Study design: This was a Cross-sectional study conducted at Radiology department of Ziauddin university. Methodology: We analyzed 270 head and neck CT scans 270 Head and neck CT scans (540 sides) were analyzed. CT was performed on a 16 slice Toshiba Alexion at Ziauddin Hospital, Karachi —removed for blind review---. SPSS version 20 was used for data analysis. Results: Out of 270 CT scans analyzed, 28 (10.3) scans showed protrusion of ICA in sphenoid sinus. Out of 45 (16.6) of the subjects showed dehiscence of carotid canal. Out of total dehiscence present unilateral cases were more frequent as compared to bilateral. Unilateral protrusion was also more common as compared to bilateral protrusion of ICA. Conclusion: Knowledge of dehiscence and protrusion related to ICA and sphenoid sinus anatomy is essential to avoid complications in endoscopic sinus surgery.
... Adequate information regarding the anatomical variations of the sphenoid sinus and its adjacent critical structures can substantially lower the risk of postoperative complications (15)(16)(17). Thus, this study assessed the anatomical variations of the sphenoid sinus and its adjacent vital structures in an Iranian population using CBCT.CBCT was used in this study since this imaging modality provides highly accurate information regarding anatomical variations in the maxillofacial region, and has been extensively used in the literature (18)(19)(20)(21). ...
Background: The aim of the study was to determine the anatomical variations of the sphenoid sinus and its adjacent critical structures using Cone-Beam Computed Tomography (CBCT). Methods: This cross-sectional study was conducted on CBCT scans of 67 females and 84 males between 18 to 67 years. Presence/ absence of intersphenoid septa, sphenoid sinus pneumatization and its type (conchal, presellar, sellar, and postsellar a and b), protrusion of the optic canal and carotid canal into the sphenoid sinus, optic canal and carotid canal dehiscence, and Anterior Clinoid Process (ACP) pneumatization was evaluated on CBCT scans, and their prevalence and correlation were calculated. Data were analyzed by the Chi-square test (alpha=0.05). Results:The prevalence of intersphenoid septa was 98.68%. Postsellar type a was the most common type of sphenoid sinus pneumatization with a prevalence of 41.3%. The prevalence of conchal, presellar, sellar and postsellar b types was 0, 11, 30, and 17.7%, respectively. The prevalence of optic canal and carotid canal protrusion into the sphenoid sinus was 50 and 52.7%, respectively. The prevalence of optic canal and carotid canal dehiscence was 48.3 and 40.3%, respectively. The prevalence of ACP pneumatization was 45%. Optic canal and carotid canal protrusion had a significant correlation with ACP pneumatization (p<0.001). Also, carotid canal and optic canal protrusion and dehiscence were significantly correlated with degree of sphenoid sinus pneumatization (p<0.001). Conclusion: Sphenoid sinus pneumatization significantly increases the likelihood of carotid canal, optic canal protrusion into the sphenoid sinus and their dehiscence, therefore, a preoperative 3D imaging is strongly recommended prior to trans-sphenoidal surgical procedures.
... Several authors demonstrated that the relationships between these structures and the SS are extremely variable, as the sphenoid bone is one of the most complex and inconstant structure of the skull base. [2][3][4] A deep anatomic knowledge of SS and sella turcica (ST) is therefore essential to improve the outcome of endoscopic transsphenoidal surgeries. In the last decades the number of anatomic and morphologic research on SS has progressively increased [5][6][7][8] due to the growing application of the transnasal transsphenoidal procedures as a mean for treatment of skull base lesions. ...
... With the growing interest in clinical studies on trans-sphenoidal approaches, a sensible increase of anatomic, morphologic, and quantitative analyses has been observed in literature to better understand the surgical working space. 2,11,[16][17][18][19] Anatomy of SS is influenced by many factors, such as age, sex, and ethnicity. [5][6][7][8]12,20 In contrast, for what concerns ST, congenital and acquired conditions have proved to be of influence on sellar size: Canigur Bavbek et al 15 Surprisingly, to the best of our knowledge no study has analyzed the possible relationships between morphology and size of SS and ST. ...
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.
... Pneumatization of SS can be minimal or substantial (18). It may extend into the basisphenoid, anterior clinoid process (ACP), greater wing (GW), pterygoid process (PP), and vomer bones, in addition to the sphenoid bone (11,38). Increases in protrusion and dehiscence of the ON and ICA into the sinus cavity are directly correlated with increases in the degree of pneumatization. ...
Aim:
To determine the clinically significant association between pneumatization types of the sphenoid sinus (SS) and protrusion/dehiscence of the optic nerve (ON) and the internal carotid artery (ICA).
Material and methods:
This prospective cross-sectional study was conducted between November 2020 and April 2021 at the Dow Institute of Radiology, Dow University of Health Sciences, Karachi. This study examined 300 computed tomography (CT) PNS patients aged 18-60 years. The forms of SS pneumatization, extent of pneumatization to the greater wing (GW), anterior clinoid process (ACP), and pterygoid process (PP), as well as the protrusion/dehiscence of the ON and ICA were examined. A statistical relationship was identified between pneumatization type and protrusion/dehiscence of the ON and ICA.
Results:
The study included 171 men and 129 women with an average age of 39.28±10.9 years. The most commonly encountered pneumatization type was postsellar (63.3%), followed by sellar (27.3%), presellar (8.7%), and conchal (0.75%). The most frequent extended pneumatization was observed up to PP (44%), followed by ACP (31.33%), and GW (16.67%). The rate of dehiscence of the ON and ICA was less than that of protrusion of the same structures. The association between postsellar and sellar pneumatization types and protrusion of the ON and ICA was statistically significant (p 0.001), with the postsellar type showing more protrusions of the ON and ICA than the sellar type.
Conclusion:
The pneumatization type of SS has a significant impact on the protrusion/dehiscence of adjacent vital neurovascular structures and should be mentioned in CT reports to alert surgeons for any disastrous intraoperative complications and outcomes.
... The SS is a mucosal lined variably pneumatized posterior extension of the paranasal sinuses, it is located within the sphenoid bone in the middle cranial fossa [40] . Its relations are ethmoid air cells anteriorly, the cavernous sinus laterally, the pituitary fossa and planum sphenoidale superiorly, and the choana inferiorly [41] . Postero-superior ethmoidal air cells can grow into the body of the upper sphenoid bone and may surround the optic canal and nerve and extend to the sellar turcica, resulting in the development of an Onodi cell [42] . ...
... The sphenoid sinus is a structure that has many variations [2]; the degree of pneumatization differs from person to person, and according to the degree, it can be divided into conchal, presellar, sellar, and postsellar types [1,2]. In addition, the intersphenoid sinus septum (ISS) exists in various numbers and forms [3][4][5]. ...
... On the sagittal plane, if the posterior end of pneumatization extended to the front of the sellae, the pneumatization was considered presellar; if the end lay between the anterior and posterior ends of the sellae, the pneumatization was considered sellar; and if the end lay beyond the posterior ends of the sellae, the pneumatization was considered postsellar. Minimal pneumatization was considered conchal [1,4,5]. ...
Objective
We explored the clinical significances of the relationships among sphenoid sinus aeration, intersphenoid sinus septum (ISS), and internal carotid artery (ICA).
Methods
We retrospectively reviewed the preoperative paranasal sinus computed tomography scans and the medical charts of 490 patients who were treated by the endoscopic endonasal transsphenoidal approach. We analyzed sphenoid sinus pneumatization, number of ISS, and positional relationships between the ICA and ISS (including ICA prominence and the thickness of surrounding bone).
Results
ISS were often present in the ICAs of patients with presellar pneumatization (36.2%; p = 0.042). Sphenoid sinus pneumatization status significantly differed according to number of ISS (p < 0.001), ICA prominence (p < 0.001), ISS insertion into the ICA (p = 0.042), and distance from ISS to ICA (p = 0.004). When sphenoid sinus aeration was poor, the ICA was not prominent, and the ISS were attached to or lay close to the paraclival ICA.
Conclusions
Patients with presellar pneumatization exhibited less prominent ICAs, and more ISS attached to or near the paraclival ICA, than did other patients. Therefore, particular caution is required when using the endoscopic endonasal transsphenoidal approach to treat patients with poor sphenoid sinus aeration.
