We're going to keep moving on. It's my honor to introduce Dr. Melling from Norway. He's going to take us through meningioma surgery. Are we making progress? Thank you. Let's see if we can change it. Well, thank you for the honor to be here. A bit of a self-congratulatory talk, I guess. So, and are we making progress? Not we as in myself, but we as neurosurgeons. Only disclaimer I have, I guess, would be some p-values. So what is progress? What do we mean by progress? And this is also something we actually should think about. I would like to define it or talk about the primary end points, what is of primary importance. Then we talk about overall survival, re-treatment, free survival, and complications. We can have secondary end points, like Simpson grade or cosmetics. Is it a small or tiny or large craniotomy, for instance? Temporal muscle atrophy. This is not the same as to say that these are unimportant, but they are unimportant relative to the primary end points. And lastly, as we've heard now, the tertiary end points, I would call them treatment costs and length of stay in hospital. At the end, this is not the most important thing in what we do, even though we have outside pressures to make this our primary objective. So how do we study progress? Also, there are many ways to skin a cat. We can have quality improvement projects. And this is like the Japanese, the Toyota story. Process evaluations, effectiveness studies, economic evaluations, and quality of studies. But if we look at the effectiveness studies, this is probably what we're most familiar with. Randomized controlled trials, sort of top of the pyramid. We have quasi-experimental designs, i.e. you can have two surgeons in one department doing two different procedures for the same disease and compare the results, for instance. Observational studies that we're mostly used to with retrospective series and systematic reviews. So meningioma surgery, are we making progress? So if we looked at 30-day mortality rate, and these are papers on meningiomas published from 1990 to 2010, containing more than 20 patients. And you can see the mean 30-day mortality rate, as far as I could tease out from these papers, 3.4%. But of course, there will be larger or smaller series, even though they all have more than 20. So if we have this weighted mean, i.e. you weight according to the number of patients included, we have 2.2%. OK? But the important thing here is the linear fit. We can see it is decreasing over time. So yes, we are. In terms of resection grade, if we define gross total resection as Simpson 1 or 2, some define as 1 to 3. But anyways, you can see here a mean of 74. Slight increase, but not so much. Weighted mean, also the same. So there is an improvement over time in the literature. Then we have the observational studies, and this is what we have done. The strength of this technique is to basically study and practice what we do, as opposed to some of the limitations that we have with randomized control trials, for instance. And it's especially useful when evaluating our sustainability of intervention. You know, changes over time. But of course, the problem is that we cannot make inferences to causality, although at the end of the talk, I will try to make some inferences. So I used our meningioma database in Oslo, 2,000 patients included here, with like 1,500, and compared two time periods, 1990 to 1999, and 2000, 2010. So these were the patients. The female, of course, preponderance, as we know. Mean age, 58 years, and median follow-up of seven years. So not these one or two years, whatever. It's problematic. T knows all about this. We need to follow this patient. One patient lost a follow-up, moved abroad, unfortunately, but otherwise complete. Anyways, location, skull base, non-skull base. So what is skull base? Definition I've used is the Al Mefti in his book. And non-skull base, or what is not skull base is then skull top, will be the rest. So compare the two time periods, as I said, patient characteristics. Do we choose different patients, outcomes, and survival? Do we operate more elderly patients now in the modern series? The answer is yes. Not a big difference, statistically significant, but 2 and 1⁄2 years. But you can see that there are more here in the 80s and 90s than in the past. So yes, we do operate slightly more. If you see here above 70, you can see that the proportion is larger in the more modern series. And we all have experienced this. Do we operate better functioning patients? Are we cherry-picking? Not if by better functioning we use, as here, the Karnofsky performance score. Operate more asymptomatic patients? Yes. You can see in the green here, these are patients that are basically asymptomatic or oligosymptomatic but have imaging, serial imaging, showing documented growth. And of course, this is also a reflection of better access to this follow-up documentation in terms of MRI, of course. Are we obtaining higher Simpson grades? Also yes. If we further sort of subdivide the two groups into four, you can see there is also a trend towards better surgery over time. 30-day mortality is reduced. So the safety of what we do is improving. And again, you can see, although this is not significant, we break it down in four, but you can see a clear trend towards lower mortality. Causing less harm? Absolutely. Relative risk of new onset neurodeficit or coming out worse neurologically than pre-op has decreased. And it's 0.5 relative risk. And again, you can see a clear trend towards better and better. So in these terms, we are improving. Infections, no difference. These are very low figures, and therefore, you would really not expect to be able to detect a difference with only 1,500 patients. And the same with the post-op hemorrhages. Retreatment-free survival is interesting. You can see here clearly that there is a significant improvement in retreatment-free survival. And the same goes for overall survival. So three major findings. We do have increased gross total resection. This has not come at the cost of increased morbidity or mortality. Rather, on the contrary, we have a decrease, and we have improved survival. And now I will try to make some inferences. So why do we see this improvement in overall survival? Is it an effect of the general improvement in health in the population? You could argue that, and it's probably a part of it. But that should not affect the retreatment-free survival. Patients, the population has not been operating in general. But you can see here, it's quite a dramatic increase, 2.3 years over this study period of 20 years. The average life expectancy in Norway has increased at 2.3 years. Is it an effect of increased health care spending? Perhaps. We do spend a lot more. Look here, Norway and the United States, again during the study period. It's a massive increase. And of course, value for money. Perhaps we are getting value for money. And as we've seen, we do have improvements. Is there an effect of some improvement of all these tiny things, improvements that we do in imaging and neuroanesthesia, microscopes, instruments, et cetera? Probably. But also, that's my last point, subspecialty training. So here is retreatment-free survival, the four time periods. And you can see that we do make progress in retreatment-free survival for every five year period. And the same is actually true for the overall survival. So not only every decade, but every five years, we have gained some tiny improvements. Is there an effect of subspecialization? This is not to pick out any favorites. I did a PubMed search, search term skull base, and publications in 1990, because this was when the study period was. And these chaps will then be sort of representative for this push into developing skull base as a subspecialization. And it's not only them doing great surgery, but it's also them pushing this subspecialization courses. So this is interesting. Here is a number of publications in Medline. So meningioma in general, meningioma in neurosurgery, and meningioma in skull base. Of course, skull base is a tiny proportion of this. But you can see here that during the two time periods, we see a dramatic increase in publications as an inference of interest in the field. If we zoom in on subspecialization, this is very interesting, because you can see some dips here. And this is where Almefti had summer holidays. But you can see the trend towards more and more publications. And actually, for every 10-year period, we have a doubling of number of publications. And again, I think this reflects the interest in subspecialization and perhaps a driver for improvement. So if we look at overall survival, we see this curve. We've seen this. This is the younger, or this is the older. If we split into skull top, there's no significant difference. Skull base, highly significant. And this might be an argument saying that the primary driver of this improvement has actually been in the skull base surgery and not the skull top surgery. A reviewer commented that we should also look at the combined effect of location. There might be differences in location between the two study groups. You can see it's also the interaction here in the cocks is also significant. And here you can see re-treatment, free survival, four periods. It's a bit complicated. Of course, this is skull base older. This is non-skull base or skull top older. But you can see this is skull base now. And this massive jump from green to orange. And this is larger than from red to blue. And again, we have the same phenomenon in overall survival. So take-home messages. We have seen quite dramatic, I would say, improvements in overall survival and re-treatment free survival since 2000. We have obtained higher resection rates without an increase in complications during this period. I think, as I've argued, that one of the primary drivers for this improvement is skull base surgery. And I think that we do see an effect of subspecialization in our results. Thank you. Thank you. All right. Great presentation. Really stimulates the thinking. I would like to ask you a question. I'm also Dr. Almefti. Is meningioma really a benign tumor? I might add, he looks the same. I'll let Almefti answer. He looks the same as he did in 1990. So the summer holidays must have worked. So this is a beautiful, scientific, conclusive study. And thank you, thank you, thank you. Now, these are a study on the surgical treated meningioma. Yeah. Because if we want to say, during that same period of time, have we made the progress in treating meningiomas, I think you're going to find totally different conclusions. Because during that period of time, you study the devilish of radiation came to treat meningioma very widely. And I think if you make that study the same study on the patient who treated by radiation, I think we're going to see a totally different picture. Do you know of anybody look at it from that? That's a beautiful study of what surgery did really with meningiomas. Do we have to compare this with what radiation did with meningiomas? And the question is good and timely. I don't have data on that. Because this database is prospective from 2003 onwards, as I said, but retrospective from 1990 to 2002. And I do have data on post-operative treatment, but the entrance ticket to the database is surgery. So I don't have the complete, let's say, meningioma management data. I don't. I cannot answer. That's a beautiful study. Thank you. Thank you. This is not the first time that you didn't answer my question, but that's OK.

meningioma surgery

progress

overall survival

re-treatment-free survival

complications