So we have time for some question and answer for our speakers, these last four abstracts before our break. So Dr. Reed, I have a question for you on the, you described the, what I'm left with is that the, there were 38 events that happened amongst all these pedicle subtraction osteotomies of which three ended up having a permanent result, which means that the surgeon's autonomic nervous system was triggered at a high level during those other 35. It's too sensitive, is essentially what I'm left with, is that, because you don't want to be dismissive of a change. At the same time, you don't want to get, it changes the atmosphere when your neurophysiologist says, I've had a decrease of 50%, 60%. Is the threshold 80, is there a better way to be doing this so that we aren't sweating unnecessarily as we're doing these procedures? Right, it's obviously disconcerting whenever you're operating and your neurophysiology person tells you that they've lost motors in any kind of significant capacity. The sensitivity may be less of an issue than being as systematic as possible about doing everything that you can do once that happens. That is, you know, at UCSF and most institutions that do these surgeries, there's a very systematic way of essentially evaluating everything that you've done, going through in a systematic way, if the blood pressure's high enough, if there's anything that you've just done that you can reverse. We essentially do everything that we can, and there is some sort of a penumbra almost of, you know, if there is something that you can correct and then you undo some of your correction, that happens relatively infrequently where you have to make a decision like that. But the most important thing is just to be systematic and ultimately, you know, it happens often enough that we're aware that it's frequently a false positive and you just do what you can and appreciate its limitations as a tool. So the three events that did occur, they're worthy of a rigorous analysis. What were the circumstances of those three that resulted in permanent injury? Right. That's typically an L5 PSO that involves a drop foot. In those cases, what we'll do is we'll systematically go through everything, raise the blood pressure, undo anything that can be redone. So all three were L5 injuries? Yeah. Essentially a persistent foot weakness, you know, a drop foot. Okay. But then we evaluate the nerve, make sure that there's nothing obvious and if there's any continuing compression, it's removed. And then we've essentially done everything that we can. Now, unfortunately, this tool sometimes is just telling you that you've done something, you know, and it's not always something that you can repair. And there was a question. Gentleman in the back. Yeah, you actually asked it. Okay. Dr. Odagwa or his surrogate, the conclusion of your abstract was to understand anemia better in the context of these large operations. What about just treating it? I mean, understanding it is very noble, but to me, what I'm left with from your abstract is don't operate on an anemic patient, get them treated, then do the surgery. Is that, I mean, is there a role for urethropoietin or is there a role for addressing that underlying anemia? Obviously, I mean, looking at your very compelling evidence to suggest that you shouldn't because you're just asking for trouble. Absolutely. Thank you for that question. And those are actually the next couple of questions that we're going to be seeking out in more prospective randomized control trials. In our experience from the literature, and of course, there's limitations to a retrospective study, we do believe it's similar to malnutrition in the sense that if you can get someone not so much at the baseline anemia right before surgery, but six weeks prior and pre-optimize them for surgery and to auto-correct their, you know, what is the reasoning for their anemia and to increase their hemoglobin, hematocrin, and so forth prior to surgery, we are hypothesizing that it will result in a better overall quality of care for these patients. However, we can't tell with what we did in a retrospective study just yet, and we hope with the future studies that we're planning as well as other studies out there that are being planned to really look at that role of pre-optimizing anemia and if that is something that we can do. Equally interesting was the statistical significance correlating anemia with durotomy. I think that's going to have to be another study as well. Since this was an institutional study that had numerous surgeons and this was retrospectively collected, we, and I think we could or we should have actually controlled for the surgeons being, who's operating, because that may be correlated to who's actually having the durotomies and who might, who might not. But with what we have, we can't make that kind of conclusion. Artifact of the statistical analysis. Yes, sir. Thank you. Unless someone else. Do you think maybe the duro just wasn't as high quality anemia in any of these situations at all? Yes, that could be. That's very possible. We think that anemia, such as malnutrition, would not be in status. There's systemic effect that impacts throughout the whole body, such as the wound healing, such as the integrity of certain tissues. And we do believe that. We don't know for sure with what we did here that, yes, maybe the duro is not as strong as it is in a healthier patient, but that is on a more molecular level that could actually be a causation. Dr. Hussain, I'm left with the impression that SINs perhaps may not be rigorous enough to select patients who would benefit from surgical intervention. Your surgical cohort certainly demonstrated a substantial decrease in pain and disability in patients with metastatic disease. But I'm left with the impression that perhaps if SINs was more rigorous in identifying those or perhaps the criteria, maybe not everyone is being captured in the current SINs scale that could potentially benefit. Am I reading too much into your data? I think that's a valid point. I would argue the opposite, that I think it still isn't even – my point of my data was to suggest that it's an even more valuable tool in assessing which patients will benefit from stabilization surgery. I think part of the reason why we're seeing a bigger correlation with preoperative symptoms, which is what I think you're getting at rather than response to stabilization, may be just because of our limited number in our cohort study. We're already in discussion with other major cancer centers in terms of pooling our data together to look at multi-center studies to see if we can power our study a little bit further that would help detect even more granular details of which patients, based on which SIN score or which SINs component score would benefit from stabilization surgery ultimately. All right, everybody. We're going to meet back at 4 o'clock. There's a beverage break with the exhibitors. So 4 o'clock to start with the Sontag lecture with Dr. Resnick.

question and answer session

complications

pedicle subtraction osteotomy surgeries

anemia

Spinal Instability Neoplastic Score (SINS)