Correlation of optic nerve sheath diameter with height, weight, body mass index and age

Abstract: The study was conducted to determine the relationship or association between optic nerve sheath diameter and age, weight, sex, height, and Body mass index (BMI) in children of the South West Nigeria extraction. A cross-sectional study was carried out among 2-14-year-old children of the selected school in a suburban town in Southwest Nigeria. Approval was obtained from the institutional Human Research Ethics Research Committee, and consent was obtained from parents of the children. Where indicated, assent was obtained from the children. A pediatric ophthalmologist ascertained the normalcy of the eyes with visual acuity, refraction and fundoscopy. Height and weight were measured according to standard protocol and BMI was calculated from weight and height. The scanning was done by a radiologist with 4-12MHz Linear transducer on a gently closed upper eyelid with a B-mode ultrasound machine (Clear Vue 550 Phillips Model). No sedation was involved. The mean ONSD for the right eye was 0.54±0.07cm (5.4mm), while the left eye was 0.56±0.07cm (5.6mm). The optic nerve sheath diameter was longer in the left eye for all subjects, and this may be due to the fact that females have shorter diameter in the right eyes. ONSD did not correlate with height, weight and BMI. The mean ONSD is affected by sex in the right eye. This may be indicative of a relatively lower intraocular pressure in the right eyes of the girls. Therefore, in the use of the optic nerve sheath diameter as surrogate for intraocular pressure, it is preferable to use the left eye in which there is no sex difference

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