Intraoperative CT-DCG Navigation Guidance

Intraoperative CT guidance. The case details I have mentioned in my introduction video.

Now here, if you look at the right nasal cavity, following maxillectomy. That is a large palatal defect there with partly mucosalized bone.

And then as we go towards posterior corner, one can notice the Eustachian tube inferior and left. And there is no discernible nasal cavity structure whether it is soft tissue or bony all across except for two discharging points. And one can notice the CT-DCG here which shows a dilated lacrimal sac.

We also created a virtual model where you can see that the right lacrimal sac is abruptly cut and sharply cut at the sac duct junction. And this is expected in cases where there is an iatrogenic removal of the bony nasolacrimal duct along with maxilla.

Now I’m trying to search for the lacrimal sac here which is well delineated as a round, globular white structure. You can see that I’m still not near the lacrimal sac. Right.

So what I’m going to use now is– I’m going to use something called as look ahead protocols where a point that I use, I would get to know in the same direction 5 millimeters, 10 millimeter, and 15 millimeters the structures that I would be encountering.

Now if you look at this particular case here, from this point, the first image on top left radiological image corresponds to the point of the tracker. The top right corresponds to 5 millimeter from that point. The bottom left corresponds for 10 millimeters. And the bottom right corresponds to 15 millimeters.

So if you see here the lacrimal sac is somewhere at around 5 millimeters from this location and continues up to 10 millimeter and not beyond that. So this gives you an idea in case there is a difficulty.