Anatomical variations of sphenoid sinus among patients undergoing computed tomography of paranasal sinus

Abstract

Background:The approach to sphenoid sinus still remains a clinical challenge, despite the arrival of endoscopy, computed tomography (CT) and functional endoscopic sinus surgery (FESS). The complex and variable anatomy of the sphenoid sinus can be difficult to appreciate with standard axial or coronal CT images of the sinus. The study was done with the objective to study the anatomy of the sphenoid sinus and its variations, and to compare the prevalence of variants obtained in our study with the reported cases in the literature. Methods: The CT scans of 168 normal slides obtained from 84 patients with paranasal sinus were analysed using triplanar imaging provided by 64-slice spiral CT. The prevalence of each of the sphenoid sinus variation was also analysed. Results: Results showed that the prevalence of pneumatization of the anterior clinoid process, greater wing of the sphenoid, and the pterygoid process was 17.85%, 22.61% and 32.14%, respectively. Protrusion of the internal carotid artery, optic nerve, maxillary nerve, and the vidian nerve was 47.61%, 36.90%, 25% and 26.19%, respectively. Dehiscence of internal carotid artery, optic nerve, maxillary nerve, and the vidian nerve was 30.95%, 29.76%, 14.28% and 22.61%, respectively. The prevalence of pneumatization in the Onodi cells was seen in 17.85% of the cases. Association of septa with an internal carotid artery was seen in 29.7% of the cases. Septa attachment to the optic nerve was also observed in 27.3% of the cases. Conclusions: The triplanar imaging (section thickness of 1 mm) is a better three-dimensional image of the sphenoid sinus, compared to coronal imaging. Triplanar imaging guides the surgical approach of the sphenoid sinus with mentally reconstructed three-dimensional images.

Pneumatization Patterns of the Sphenoid Sinus in Adult Nigerians and Their Clinical Implications

“…The prevalence of the pneumatized anterior clinoid process (22.6%) was higher than the reports in previous Nigerian studies by Fasunla et al, Onwuchekwa and Alazigha, Famurewa et al, and other studies outside Nigeria ( 5 , 6 , 7 , 12 , 18 ) ( Table 4 ). However, Joghataei et al and Gungor and Okur documented higher frequencies in Iran and Turkey respectively ( 2 , 19 ) ( Table 4 ).…”

“…Pneumatization of the greater wing of sphenoid and pterygoid process is important to surgeons since it renders the maxillary nerve, vidian nerve, and ICA susceptible to iatrogenic injury and neuralgia in sphenoid sinusitis ( 4 ). The endoscopic endonasal transpterygoid approach to the central skull base uses a pneumatized pterygoid process to access the middle and posterior skull base for biopsy of lesions or repair of CSF leaks ( 7 , 19 ).…”

“…The sphenoid sinus is bounded by the hypophyseal fossa superiorly, the nasopharynx inferiorly, the cavernous sinus laterally, the ethmoidal sinus anteriorly, and the brainstem posteriorly ( 1 , 7 ). It is abutted by vital nerves and vessels such as the internal carotid artery and optic nerve whose positions in relation to the sphenoid sinus vary due to high interindividual variability in its pneumatization ( 8 , 9 ).…”

Anatomical Analysis of Sphenoid Sinus and its Surrounding Structures in Cone-beam Computed Tomography Images: A Retrospective Cross-sectional Study

“…Singh (2019) examined 84 CT images and reported the prevalence of pneumatization to the greater wing of the sphenoid and the pterygoid process to be 22.61% and 32.14%, respectively (22).…”

Anatomical relationship of pterygoid process pneumatization and vidian canal

“…Of particular note, among limited studies reported from India, Kirtane et al have evaluated the use of vidian neurectomy for crocodile tears, a sequelae lesion of the facial nerve. 24 Bhanu Pratap Singh et al, 25 Sushil Kumar Kashyap et al 26 and Prabu SS 27 have noted protruded and dehiscent vidian canal while studying variations in sphenoid sinus. They have not evaluated the degree of pterygoid process pneumatization.…”