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Deep Vein Thrombosis – A Preventable Complication

One of the biggest worries for anyone undergoing surgery is the chance of post-op complications. This is also a major worry of your surgeon.

One complication of major surgery, especially a long (greater than 2 hours) surgery, a recovery time that requires bedrest, or a procedure that requires a blood transfusion, is a deep vein thrombosis.

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Deep vein thrombosis (DVT) is clotting of blood in a deep vein of an extremity (usually calf or thigh) or the pelvis.  It is usually the primary cause of pulmonary embolism (PE) which is when the clot (thrombosis) travels to the lungs and immediately affects the breathing of the patient.  DVT results from conditions that impair venous return, lead to endothelial injury or dysfunction, or cause hypercoagulability (blood more likely to clot easily).  DVT may be asymptomatic or cause pain and swelling in an extremity. Symptoms of a PE are chest pain, shortness of breath and a decrease in the oxygenation of the blood.

There is always a chance of developing a DVT , so something must be done before, during and after surgery to prevent it. Long surgeries and recoveries are often unavoidable, so most hospitals and surgery centers have protocols set up.

Protocols generally include mechanical therapy (e.g. Compression devices or stockings, venous filters), and drug therapy.
Mechanical devices are SCD’s (Sequential compression devices) and these are the pumps that are wrapped around your calves and are on constantly during the surgery and recovery, when not ambulating. Venous filters are generally put in the patient’s vena cava (small invasive procedure usually done in the x-ray department) and “catch” any clots that may be headed for the lungs. This does not prevent DVT, but hopefully prevents a DVT from becoming a pulmonary embolism.

Drug therapy can include low dose unfractionated heparin (1 injection 2 hours preop and every 8-12 hours for 7-10 days or until ambulatory), low molecular weight heparins (more effective and much more expensive) or Fondaparinux (which is possibly more effective with orthopedic surgeries). People who are already on a blood thinner such as Warfarin are generally taken off that and put on the previous drugs as they make the chance of hemorrhage during surgery less likely. Warfarin would be restarted at least a day post-op once the chance of bleeding is low.

Early mobilization, leg elevation, compression devices, elastic stockings and anticoagulants are all recommended preventative measures.  Patients who should not receive anticoagulants may benefit from the mechanical measures alone.

Discussing news and issues in orthopedics and spine healthcare. This is Spine Talk. Hi, this is Dr. John Shim, and today we're gonna talk about the topic of deep venous thrombosis and spinal surgery. I have Jason Mazza orthopaedic assistant here with me, and he's going to review an article called "Risk factors and pharmacologic prophylaxis for venous thromboembolism and elective spinal surgery" published in a Journal of Spine in 2018. Jason, can you tell us about this article? Yeah, so this study comes to us from from Yale University. This was a retrospective study that was performed. The authors of the study took a look at a huge database of a hundred and nine thousand plus patients from elective spine surgery over the course of about a nine year period. In addition to looking at one institution of twenty eight hundred and fifty-five patients over a course of a three-year period the incidence of venous thromboembolism in the database was 0.61%. At the academic center It was twice that. It was 1.23%. At the academic center they did point out that all of the patients were also given sequential compression devices and early emulation to help again minimize the risk of VTE. The results of studies somewhat interesting they're independent risk factors for VTE were determined to be greater age, male gender, increased body mass index, dependent functional status, lumbar spine surgery, longer operative times, longer length of stay, and other post-operative complications. Kind of the bottom line from this though is that Pharmacologic prophylaxis did not significantly influence the rate of VTE with associated increase though in risk of epidural hematoma following surgery and returned back to the operating room. So, Dr. Shim this again it kind of a little bit controversial issue with this. When we talk about general orthopedic surgery when we talk about like hips and knee replacements and hip fractures we know that the risk of VTE is very high and there is a kind of a standard set of guidelines or Kind of a general standard that we follow in providing patients prophylaxis. When it comes to spine surgery though the risk a little bit lower, but we're doing a kind of multitude of different types of cases where the risks may vary, and there is no standard present. So, it comes down I guess to the surgeon determining if pharmacologic therapy or prophylaxis is necessary. From your perspective, what do you look at in a patient's history or what other factors do you consider whether to determine if the patient needs Prophylaxis or not? Well, I think we got to go back a few steps to have this discussion for our listening audience and for our patients. VTE, we're going to use medical jargon, but really what we're talking about blood clots that typically come from your legs and those blood clots can travel. They can travel to your lungs and cause some pretty bad things. You can have something called a pulmonary embolus. Where the blood clot basically stops the blood flow into your lungs and it could be a really bad problem, and actually some people can die from that process. So this is a really significant problem. As orthopedic surgeons doing hip replacements, knee replacements, and trauma care it's a big problem. Because the number of people who develop these blood clots through the legs are pretty significant. That's why there's lots of information about how to prevent it, what kind of treatments we can do, we can give medications, we can get blood thinners. We can even for some really sick patients they even talk about putting these things called umbrella devices to try to capture the blood clots as they travel up towards your lungs. We know it's a problem in orthopedics. Is it a problem in spinal surgery? I think one of the things that's coming out of the study is there are risk factors. Well, these are the same risk factors that anybody has to develop blood clots. I mean, I'm sure we've taken care of patients before. There are certain patients who are susceptible to blood clots, and we're very concerned about it. We know that ahead of time. So the question is how do you counsel these people, and what do we do for them? So, what is your perspective on this Jason? Because for me it tells me it's more about patient selection than anything else. We have to choose people with the lowest risk to perform the surgeries to decrease the chance of having these problems. If they're higher risk, we have to spend a fair amount of time counseling them. What is your takeaway when you read this? No, I agree that that is it's kind of a more of a individualized approach, especially when it comes to elective spine surgery. By kind of doing a standard set of guidelines I don't think it would ever work even just across if we look at just like lumbar surgeries. There are certain procedures regular general healthy patients. Yes, there's always going to be a risk of VTE, but the risk may be greater in trying to prevent that risk. So, I think that to me from from reading the ...just this article not looking at the other literature, I would take away from this that it has to be an individualized approach again. And as you mentioned there there are certain risk factors that we know Raise those risks up considerably and those are the people that we really have to to look at closely. Well, the other thing that the article also points out is there's risks associated with using these pharmacologic agents. These are blood thinners. So, as spinal surgeons, one of the biggest concerns we have is development of blood clots near the nerves near the spinal cord, and that blood clot expands and causes more pressure, and then causes another set of complications and problems. The study does show that there are some risks to using these pharmacologic agents. So again, we have to weigh the risks. There's a risk of developing blood clots, there's a risk of having complications. Again, a lot of this comes down to patient selection. In other words, what is that person like? If they're.. if they have an increased age, if they're obese, if they've had a history of blood clots, if they have a history of some sort of condition like cancer for instance. Cancer has an increased rates of blood clots whatnot, but we have to consider all these things while we have the discussion with patients about doing surgery. A lot of the surgeries we do are elective. In other words, there's a choice. So, are patients being properly counseled? Are they going in with eyes wide open about these risk factors? Let alone to standard risk factors of any surgery. Now, there's also risk factors of blood clots. Again, it's always to me a discussion about their overall patient status. It's individualized to the patient. The science is never perfect in that the science experiments that are being done are perfect scenarios where you have everything exactly the same step one condition and you try to differentiate that one condition. Taking care of patients, we know that doesn't actually exist. So to me that's where the art of medicine versus the science of research kind of has to intersect. So, from your standpoint reading this. You see our patient population. We haven't really done this chemical prophylaxis in our patients because we're taking care of healthier patients or we're doing smaller surgeries. Do you see anywhere where we probably could consider or should consider using these medications? I guess for potentially if we were kind of going outside of our patient population. Maybe the large lumbar cases again where they have some of these known risk factors then it would have to be again, a discussion of risks and benefits. Does the the risk of giving them prophylaxis outweigh, or the benefit.. excuse me, of giving them proflex outweigh that risk of them developing some post-op interoperative or post-operative complications. One of the things that I was kind of looking forward to studyi, and I didn't quite see is dissecting out "Are nonpharmacologic treatments actually beneficial"? A lot of patients have what's called SCD's. Sequential Compression Devices applied to their legs. It actually squeezes their legs, and had the blood flow through their veins. So, theoretically allows more circulation. So, less development of blood clots. A certain number of patients in these studies were using those mechanical compression devices, and some were not. I don't recall them stripping this out for us to really understand is that an independent factor? We can share with our patients that we actually use SCD devices on most of our patients who require lumbar surgery. Not so much for the smaller ones, but certainly the longer operations. It's pretty standard for us to do. I was surprised they actually didn't dissect that down. So, you know and my concern is we do things for patients because we've always done it that way. The question is Is that actually, really what happens? Is that really benefit people or not? So, you know, we have to think of ourselves and be retrospective in what we do and hope that our conventions are still beneficial to patients. All right, so this is Dr. Shim here with Jason Mazza, talking about deep venous thrombosis and spinal surgery and the ramifications of using medications to try to control it. I hope this is informative. If you have any issues about this and have concerns, please discuss this with your surgeon before you have your operation. Have a good day.

Last modified: April 1, 2019

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