Well, thank you for inviting me for a talk here. This project is about the impact of patient-controlled analgesia, PCAs, on clinical outcomes after posterior lumbar spinal fusion. I'm a medical student at University of Arizona College of Medicine, Phoenix. I'm my last year there. So these are the disclosures. So a little bit of introduction on this topic. The optimal postoperative pain control is pretty critical following posterior lumbar surgery. A lot of literature has shown that improper pain control following surgery can actually reduce or worsen the overall outcome of the surgery. And there's a lot of variability in what modalities as well as what avenues people use to accomplish that pain control. So one of the things that we wanted to really compare is whether patient-controlled analgesia, PCA pumps, or NCA, which we described as nurse-controlled analgesia. And that's a combination between PRN and scheduled opioids. We wanted to see if one was better than the other, if one was providing better pain control, if one was leading to more or less opiate consumption, or influencing length of stay. So some of the background literature on this topic, there's not too much out there regarding PCA usage following posterior lumbar surgery. However, the limited research that was available showed that PCA usage after posterior lumbar surgery led to increased patient satisfaction and increased preference for the use of PCA. However, it led to overall total increase in opiate consumption, as well as an increase in medication errors, and there was no difference in pain scores. So when you put all those things together, it kind of tells you that maybe you shouldn't use a PCA. So the methods that we used here were, it was a retrospective review. We looked at all patients undergoing open posterior lumbar or lumbosacral spinal fusion. We collected all consecutive patients who were undergoing the fusion for degenerative disease. A lot of patients were excluded. So if the patient was getting surgery for infection, oncology, trauma, or deformity, they were excluded from our series. We had a total of 240 patients that we looked at. And we scrutinized their records and collected all the data of what they were prescribed, how much they took, and as well as looking at the adverse outcomes. We had a lot of primary and secondary outcomes that I go over here. So all the outcomes that we looked at, we collected data, of course, on age, duration of surgery, numbers of levels fused, operative indication. And the one thing that we really looked at was their daily preoperative opiate consumption. And the way that we collected that information was that not only did we look at the clinic notes, but we referenced that information against the national databases and the PMP prescribing databases so that we could verify whether patients, you know, we get the exact number of what patients were consuming. We asked them their preoperative pain score. We also looked at ASA grades. And our primary outcomes that we wanted to measure was postoperative 72-hour opiate consumption, 24-hour pain scores, 72-hour pain scores, and then length of stay. And we wanted to compare that between patients that were prescribed PCAs and the patients that were given NCA, as well as looking at adverse outcomes between the two groups. So here's the overall results. The first table over here kind of goes over the demographics of all the patients. So like I mentioned, 240 total patients. Average age was about 64 years old. And the preoperative daily morphine equivalents of all 240 patients was 30.73. So we converted, you know, whatever opiate they were taking, we converted them to MMEs, morphine mill equivalents. And we compared them. But one of the things that we noticed was that there was a wide range in, there was a lot of variability in terms of what patients were taking preoperatively. And it made sense to use a substratified analysis after all the data was collected. So I'll go over that in a minute. But one of the common things that has been well-published in literature is that patients who have a high preoperative daily MME consumption end up consuming more opiates post-operatively. So this was an additional kind of analysis that we did just to verify and, you know, make sure our data was good. That you can see here with good correlation, with a positive correlation, patients who consumed more preoperative daily opiates ended up consuming more in the 72 hours post-op as well. And that was certainly expected. So here's some of our initial data. Like I mentioned, we substratified our data. So we broke down those 240 patients into patients who were preoperatively opiate naive, meaning they hadn't taken any opiates preoperatively. So that was zero MME. For low, we categorized that as anybody taking less than 60 MME daily. High was categorized as 60 to 90, and then very high was greater than 90. So what this shows you is there's 72, total 72-hour post-operative opiate consumption in the first 72 hours post-operatively. So if you look, here's the critical difference here. In the naive group, you can see that they consumed almost twice as much. If you prescribed a PCA to a patient who was not taking opiates preoperatively, they consumed twice as much as opiates in the three days following surgery. That difference was not only present in the opiate naive group, but every single group. So even if patients were taking low amount of opiates preoperatively, again, the PCA group, this darker orange column, they consumed more than if they were prescribed scheduled or PRN drugs. Same difference in high, same difference in very high. However, even though they consumed more opiates, the next question to ask is, was there a difference in overall pain scores? So that's the next analysis that we did here. So I have the p-values on the next slide here, but if you look at the differences, here in the naive group, that mean 24-hour post-operative pain score, they had a higher overall pain score in the opiate naive group, and this was a statistically significant difference. So we concluded that a PCA, a patient who's opiate naive preoperatively is given a PCA, they're gonna consume twice as many opiates and have a worse pain score. I think those are two great reasons to avoid PCA in that cohort of patients. For the other three cohorts, for low, high, and very high, these p-values were not statistically significant. However, the study may have been underpowered, so it wasn't powered to do this substratified analysis. So that is one of the limitations. However, we found a major difference in the naive group. And then again, like I mentioned, we looked at mean 24 to 72-hour post-operative pain scores to see if it was a little bit different after the first day. However, the same differences were present where there was a statistical significant difference in the naive group, and there wasn't one in the other three groups. So the overall outcomes, so within, like I mentioned, within the opiate naive group, patients who received PCA consumed statistically significant doubling of total post-operative opiates, and that's 152 daily equivalents versus 60, and that was a p-value of .003. And again, this difference was present in every one of the categories. So low, you had a higher opiate consumption. High, as well as very high. Everybody consumed more when they were given a PCA. However, the pain scores weren't necessarily that different. So within the opiate naive group, patients who received a PCA had a significantly higher mean operative pain score. Although this is not even a full point higher, we were considering a statistically significant and saying that they had a worse pain score. And this difference is also present in the highest post-operative pain score group as well in the first 24 hours after surgery. So the p-values for those two were .46 and .007. And we didn't find any difference in length of stay. So like I mentioned, we looked at some other outcomes as well, seeing if PCA versus NCA influenced length of stay, seeing if it influenced operative time is another one that we looked at, as well as adverse outcomes. And we didn't find any difference in any one of the substratified groups. So the summary and conclusion of this information is that post-operative PCA uses is associated with significantly more opiate consumption and equal or worse post-operative pain. So while it's a strong consideration to not use PCA because patients will consume more opiates, their pain scores aren't necessarily different. So really the next consideration is that if patients have a higher satisfaction and preference for using PCA, it may still be indicated to go ahead and do it. And in opiate-naive patients, PCA usage led to both increased opiate consumption and worse. So I think, lastly, looking at the substratified analysis, the one cohort that PCA uses may want to be avoided in is patients who are not consuming opiates preoperatively. Thank you. time of, you know, patient satisfaction, did you look at those patients that received nurse-controlled anesthesia as opposed to PCA? Which subset was happier? Which one were more satisfied? So that was something that we really wanted to include a part of our study to look at patient satisfaction surveys following their admission to see if they had a huge difference in the two groups. However, that's not something we did include in our study, at least not in the abstract. That's a part of the overall project that we're putting together for publication. It'd be interesting to see if the PCA patients are happier because they're controlled. Exactly. And the literature on that subject shows that patients who are prescribed PCAs do have higher satisfaction and higher preference for getting PCAs. So that, like I mentioned, you know, during the presentation, that I think that that alone, you know, if the pain scores aren't different, might be an indication to go ahead and do it. You may have touched on this, but your sampling of your treatment groups, was it a homogenous sample or did you take all comers? Was it a spine population? Yeah. So I mentioned a little bit about the inclusion and exclusion criteria. So the inclusion criteria were all patients who were receiving posterior spinal surgery, but we were excluding patients who were getting that posterior spinal surgery for infection or for oncologic reasons and for deformity reasons as well. Thank you.

medical student

University of Arizona College of Medicine

patient-controlled analgesia

posterior lumbar spinal fusion

clinical outcomes