 Good morning all. I'm Dr. V.B. Raseefa, PT resident from Bushfugli Institute of Medical Sciences and Research Centre, Theravilla, K.L. My discussion topic is relationship of optic nerve canal to the posterior panacea sciences on computer tomography in Indian population. So, let us have a brief introduction. We all know that posterior ethmoid and the sphenoid sciences constitute posterior panacea sciences. The optic nerve develops prior to the development of the panacea sciences and hence, it is responsible for congenital variations along the wall of the sciences. The most common position of optic nerve canal with sphenoid sciences is the supra-largeu position. So, these sciences show varying degree of pneumatization and extensive pneumatization of the sinus and body dehiscence predisposes to the optic nerve injury. The posterior ethmoid cell, that is the onodic cell, is of great surgical importance when the optic nerve is seen along its lateral wall and surrounds the nerve. Therefore, detailed knowledge of identification of the structures and relationship of the ONC with the posterior panacea sciences is the roadmap for the preoperative evaluation of FES, which is the accepted technique for treatment of sinusitis and hence, to avoid unintentional complications of the optic nerve. Now, the aim of my study is to determine the patterns of relationship of optic nerve canal with the posterior panacea sciences in Indian population. Now, the method. It was a retrospective study that was done on 100 individuals, that is 36 females and 64 males using 128 slice multi-detector computer tomography, that is GE optima. And it was done with a section thickness of 0.625 mm in a coronal section of bone window. And the study period was extending from June 2021 to September. All patients who underwent computer tomography of the perinus sinus with multi-planar reformation were included in the study. And the exclusion criteria was for patients with history of trauma to the sinus and children below the age of 13 years. So, a total of 200 ONC and their relationship with the posterior panacea sciences were evaluated. Bony dehiscence and dermatization of the anterior canal process were also evaluated separately. The types of optic nerve canal was classified based on modified Delano et al classification. And this Delano classification was modified in the study conducted by Itaghi, where type 1 and 4 mean the same, but type 2 and 3 were classified based on the degree of projection into the sphenous sinus. That is, if it is less than 50% projection, that is designated as type 2. And if it is more than 50%, it is designated as type 3. Now, type 1 where the canal is super lateral to the sphenous sinus without indentation on the sinus wall. And type 2, when there is indentation on the sinus wall, which is a 4-wall condo with less than 50% protrusion of the nerve. And type 3, where the optic nerve was traversing through the sphenous sinus with more than 50% protrusion of the nerve circumference into the sinus. And type 4, where the canal is adjacent to the sphenous and the posterior to the sinus or the presence of an odyssal, designated as type 4. Now, the result of my study came out as the most common ONC was the type 1. That is, the condom for nearly 62% followed by type 2 and 3. That is 15 and 13.5% and least was type 4, that is 9.5%. And borne dehesants were seen in 12% of the cases and neumatization of anti-diacrylonal process in 11%. Borne dehesants and neumatization of the anti-diacrylonal process were mostly seen in type 3. Now, this is a pictorial representation of the prevalence of the types of ONC. In this also, we can see that type 1 was the most common one either in on right and left, nearly 62% as a total. And type 4 was the least one, that is 9.5%. And next, this is a block presentation of the same. And next is the prevalence of borne dehesants and the posterior, the neumatization of the anti-diacrylonal process. This, we can see that out of the total types of ONC, the borne dehesants was most common with type 3, that is accounting for nearly 59.3% of the cases. That is nearly, we have type 3 nearly 27 ONC, it's where identified. And neumatization of the anti-diacrylonal process was also most common in type 3, nearly accounted for 48%. This is a block presentation of the same. So optic neumatization is one of the most catastrophic complication of sinus surgeries. Hence CT imaging prior to the surgery is an excellent modality, as it is not only to demonstrate the bone but also the air pockets and the soft tissue. Optic neumatization is usually protected by the bohe covering of the spina and vertebrae. Excessive neumatization with extension into the angitirine posterior cleaner processes, another risk factor for complications during sinus surgeries. Increased neumatization of the posterior etymodiasis that you own or resell forms the boundary of the ONC causing optic nerve injuries during the FES procedure. So in our study out of the 200 optic nerve canals evaluated and already discussed we have 124 that is nearly 62% of the cases were type 1 and the least was type 2, 9.5%. As well as the prevalence was of morning dehesants and neumatization of the anti-diacrylonal process was most common in the type 3. So we can see this is the type 1, we can see the indentation of the optic nerve. Not indentation, just to just seeing this adjacent to the spina sense on the right side, you can see the type 1. Next is type 2 with mild indentation less than 50% indentation and type 3 with a small than 50% involving the surrounding the nerve and type 4 with bilateral onodic cells and you can see the neumatization of the anti-diacrylonal process and the morning dehesants and thinning off. So to conclude the relationship of optic nerve canal to the posterior patterns of sinus varies in different individuals with type 1 being the most common type 2 and 3 with morning dehesants and neumatization of the anti-diacrylonal process and type 4 tend to cause complications like optic nerve injuries during sinus surgeries and surgeons being aware of this and avoid serious injuries to the optic nerve. So preoperative empty CT help radiologists to identify the type 4 and C and it is beneficial for the surgery surgeons so as to prevent atrogenic nerve injury during FES. Thank you.