Variant neurovascular relations of the sphenoid sinus in adult Nigerians.

Background: With the advent of endoscopic sinus surgery, the variant neurovascular relations of the sphenoid sinus are important to surgeons to minimise the iatrogenic complications. This study elucidates the variant neurovascular relations of the sphenoid sinus in adult Nigerians.

Materials And Methods: This study was conducted at the Radiology Department of Delta State University Teaching Hospital after institutional approval. Brain computed tomography images of 336 patients, aged ≥20 years and spanning over 5 years' duration were utilised. We evaluated the sphenoid sinus for protrusion and dehiscence of neurovascular structures bilaterally. The position of the optic nerve in relation to the sinus was classified from Type 0-4. The Statistical Package for the Social Sciences software version 23 was used for the data analysis. The Chi-square test was used to probe for the association between the variants with regard to side and gender. P < 0.05 was considered statistically significant.

Results: Dehiscence and protrusion of the internal carotid artery (ICA) occurred in 34, 10.1% and 83, 24.7% patients correspondingly. The dehiscence of optic, maxillary and Vidian nerves was (26, 7.7%), (60, 17.9%), and (53, 15.8%), whereas the frequency of their protrusion was (50, 14.9%), (76, 22.6%) and (87, 25.9%), respectively. All these variants except the ICA and maxillary nerve dehiscence showed a significant association with the side of occurrence (P = 0.001). Out of the 672 optic canals evaluated bilaterally, a preponderance of Type I (534, 79.5%) was observed followed by II (96, 14.3%), IV (35,5.2%), III (7, 1.0%) and Type 0 (0, 0%).

Conclusion: Our study has shown that the neurovascular relations of the sphenoid sinus vary from previously documented reports, thus confirming the need for pre-operative evaluation.