3. Tissue Healing Stages

Remember these terms? Hemostasis, Inflammation, Proliferation, and Tissue Remodeling? Here, we cover a brief overview of what these stages are all about so that we can understand what normal healing looks like in case we need to recognize when abnormal healing is taking place. 

The purpose of this podcast is to provide useful, condensed information for exhausted, time-crunched Physical Therapists and Student Physical Therapists who looking to build confidence in their foundational knowledge base and still have time to focus on other important aspects of life. 

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Transcript

 Hi, welcome to PT Snacks Podcast. I'm Dr. Kasey Hogan, and I'm so glad that you could join me today. This podcast is meant for physical therapists and physical therapist students who are short on time but need bite-sized snippets of information to help them really bring out the best in their practice. Hey, welcome back to PT Snacks Podcast. This is Kasey Hogan, your host. So last week we covered red flags, which are extremely important to master in your practice. So if you missed it, go ahead, skip back one episode, review it. It's going to come in handy, I promise. But this week we have coming at you the enthralling subject of wound healing. Why? Because we heal people, that's why. No, I'm just kidding. Because the body is really good at healing itself until it isn't, and usually when it isn't, people need a little help getting there. But we have to know what normal is in order to be able to recognize what's not normal. Chances are you'll treat someone who has a wound, whether it's from an injury, surgery, or whatever. Not everyone heals the same at the same rate, so understanding the healing process can help us to help someone that much faster if something just doesn't seem right. So what are some of ... some factors associated with tissue healing timeframes? We'll cover this in a future episode, so stay tuned, and, uh, let's dive into it. So the healing process, four phases of wound healing, so that's hemostasis, inflammation, proliferation, and tissue remodeling. It's not typically something I personally think about on a normal dai- basis, so we're gonna review it a little bit so we can get more into how that process is affected, because not everyone goes through each of these stages at the same rate. So for a brief review, we'll go over each stage. Keep in mind, though, this is just an overview. I'm simplifying a lot of things here, so there's a lot of details we won't get into on this episode. So back into it. First, we have hemostasis. So this starts immediately when someone gets a wound. In this, we're basically trying to make sure that we stop bleeding. So the body tells the vessels to tighten up so less blood can leak out through a process called vasospasm, and then it tries to basically plug up the wound with a platelet plug formation. Next, the body has clotting factors to deposit fibrin on the platelet plug, and then it creates a blood clot. And now that we have a blood clot, the wound is temporarily stabilized to at least make sure that we don't bleed to death. So we've met the goal of our first priority. Don't bleed to death. Boom. Hemostasis. Now what? Step two, inflammation. There's probably some nice, lovely necrotic tissue that needs to get out of that space so we actually have space to rebuild our new tissue. The body uses inflammatory cells, neutrophils, and macrophages to instigate this process of breaking down and removing necrotic tissue. It also uses the macrophages to secrete chemical mediators and growth factors so we can get into the proliferative phase. So that would be the next one. So now we've moved on to the proliferative stage of healing. That's number three. So far, we've stabilized the bleeding through hemostasis. We've created an inflammatory process to signal the body to clear out the dead tissue and get us ready for the next step. Now let's rebuild. The body has started multiplying cells like crazy to replace the damaged tissue because our lovely little blood clot is not meant to be a long-term fix. But you know what? To support this process, the body's gonna need nutrition and oxygen, and the best way for it to get through is a process called angiogenesis. So basically, we're rebuilding the supply channels we're going to need to transport the goods to our new construction site. AKA, your body is going to be forming new blood vessels, whether through the tissue or branches of the old vessels. So at this point, we're starting to form granulation tissue with its new capillaries, its fibroblasts, and residual inflammatory cells from the last step. Then we have remodeling. So the body is undergoing a lot of collagen synthesis that starts a few days after the injury, but it actually keeps going on for weeks. The body only needs so much, so cellularity and vascularity are going to decrease. It's kind of like when you see a house being built. Initially, you see a lot of big equipment laying around and supplies, but as the outside gets finished, you need less and less big equipment and manpower and more so the finesse inside to be finished. So somebody has to be able to install the light fixtures, put up the backsplash, et cetera. It's the same with our bodies. We've already got the bigger scaffolding up and finished, so we don't need as much of the big guns. We can step away from that for a little bit. Now it's time for the finesse. The scar is going to start to contract, and the body will start replacing the initial Type III collagen fibers with Type I, which are a little bit stronger and has more crosslinks. This process can be months or years after initial injury, but eventually, we ideally end up at some version of healed. So again, that's hemostasis, inflammation, proliferation, and tissue remodeling. Depending on where you read about this in different articles or books, they're going to group them slightly differently, but the process is still the same. The body tries to stop imminent death by plugging up the open wound and clearing out the damaged tissue to make room for brand new tissue that will have to be trained into its final masterpiece. So hope that was helpful to you because this is going to be a foundation for building on with things that can go wrong with healing, tissue healing timeframes and different tissues and all that fun stuff. So if you liked what you heard, do me a favor and write a review, share this with your friends, all that good stuff. Reach out to me if you have any questions or things you want to share. You can find me at ptsnackspodcast.com. Otherwise, thank you so much for listening and until next time, friends.