Did you account for age adjustment when you looked at the statistical benefit that you showed for the valves that you turned up and had lower revisions? So yes. Again, we noted that the youngest children were in group one, but those were not necessarily the ones that had the youngest, excuse me, the most revisions. And so we did see a difference in the age regardless of the group number. Does that answer your question? So I'm interested. I assume group one were differential pressure valves. What was their opening pressure? And then in group three, what did you turn the valves up to and what determined when you were going to stop? Excellent question. I don't have opening pressure data on most of these children, unfortunately. I meant, was it a low pressure, medium pressure, or high pressure valve? We had some of each. Most of them were medium pressure. But yes, we do have, I have that data available. In terms of, sorry, I've already forgotten the second part of your question. How did you decide to turn up the valves? What prompted? When did you stop and why? Yes, thank you. So we would see them in routine follow-up. They would come back at about one month, making sure that the incision had healed, and at that time we would get a fast MRI scan, just a T2 sequence so we didn't need sedation, and look at the size of their ventricular system. If it had come down significantly in size, then we would turn up the valve one setting, essentially. So it was a .5, 1, 1.5, 2, 2.5. And we would do that at about four-week intervals until the ventricles had stabilized. So if the ventricles were getting too big, then we would stop. If the ventricles were still getting smaller, we would keep going up. As far as ventricle consider, I mean which ventricle hole you put in the frontal or occipital, have you compared these two sites with the subdivision, I mean the subdivision has any relationship with position of the ventricle consider? I think it's entry point. Right. There has been data coming out suggesting that one entry point is more revision prone than another. The vast majority of our shunts are done parietal-occipital, so that wasn't something we looked at because of the low numbers of frontal shunts. I think we had two or three that had a frontal shunt as compared to 75 or 80 that had a parietal-occipital shunt. So that wasn't something we could look at in our data. Did you take a look at the ventricle size at a delayed time point? Can you show that this turning valve up changes the ventricle size? We did. And we have gone through that data. We're still trying to come up with the best way to analyze that particular data. I know the Toronto group has had great success with the frontal-occipital horn ratios. When we went through and did those numbers on our patients, they didn't make any sense. They did not correlate at all with the Toronto group's set of numbers. So we haven't found a good way to quantify that yet. So it's something we're working on, but haven't quite nailed down yet. We did see, ultimately, that they would stay bigger with turning the valve up.

valve adjustments

younger children

revision

opening pressure

ventricular system