by Stuart Enoch, PhD

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    00:01 Now if you...

    00:03 if you understood the important basis of fluid resuscitation, the depth, this is what is going to be asked, there is no absolutely nothing else they can test you.

    00:19 No, I think no, that's the sort of moral in mainstream.

    00:23 That would be under the wound healing, wound healing is a syllabus in your exam, and that can be around three to four questions.

    00:31 So there may be questions wound healing, they'd be one on skin graft, then one later, is it plasty or the types of flaps? I haven't got slides on that though.

    00:42 There are be reason I thought, I thought you guys will know it.

    00:49 It's not a big topic, but you need to know is, are you all sure about those areas? Not really, not really, anyone, not really.

    01:00 You're okay with the different things? I can spend about 10 minutes to go through the importance through slides.

    01:05 Otherwise? Okay.

    01:13 I'll do the local anesthetic as a presentation, then we'll go through the other bit.

    01:19 Or maybe to take a break, we'll do something else.

    01:25 Okay, so the questions, I'll just discuss the questions.

    01:33 You know the Oxford University first used to have a passage syllabus.

    01:37 Remember that? Have anybody use that? They had to a mass is part A resource.

    01:42 Is called pass it down OUP.

    01:44 Nobody's used it.

    01:45 No, no, that has been shut down.

    01:48 Anyway, I used to moderate questions for that.

    01:50 So I know pretty much what has been asked.

    01:53 So I'll just cover wound healing, what comes up? Types of wound healing and the phases of wound healing.

    02:01 Okay.

    02:01 So the four phases of wound healing.

    02:04 So let's say you have a arm leg trauma laceration.

    02:12 What happens immediately? Hemostasis, what are the components of hemostasis? What's the first thing that happens? Before that? What's the first thing? Endothelial Injury.

    02:26 The first thing that happens is sympathetic response based on constriction.

    02:31 Yeah.

    02:31 The first thing is basic constriction, followed by platelet aggregation.

    02:36 You have platelet aggregation.

    02:38 Then you have the intrinsic and extrinsic coagulation pathways.

    02:42 So, three things happen, basic constriction, platelet aggregation, and coagulation pathways activated.

    02:49 So, this is why when the patient is on aspirin, platelets are affected.

    02:54 Okay, the next thing.

    02:56 What's after hemostasis? Inflammation.

    03:01 Okay, questions in your exam.

    03:04 What are the cell types you see in inflammation? What's the first one? Neutrophils.

    03:10 First is neutrophils.

    03:12 In the first 24 hours, 24 to 72 hours, you get lymphocytes and macrophages.

    03:18 Another question.

    03:19 Where'd you get macrophages from? What are macrophages? You're right.

    03:24 So, they are normally present in the blood.

    03:28 The undergo a phenotypic transcription when they come to an injured site to become...

    03:34 to convert, to change from monocytes to macrophages.

    03:38 What's the next stage in wound healing? So hemostasis, inflammation, third one? What's a space called? Proliferation.

    03:48 Okay, so hemostatic phase inflammatory phase, proliferative phase.

    03:54 What happens during proliferative phase? So during the proliferative phase were...

    04:01 you can even imagine, you have a wound that bleeding has stopped the neutrophils have come in.

    04:09 It is cleaning up the wound, macrophages are coming to clean up the wound.

    04:12 So, they're essentially laid the groundwork for new blood vessel formation, new fibroblasts coming in, new extracellular matrix, new collagen.

    04:22 So this is all part of proliferation.

    04:24 So the five components of proliferation are angiogenesis, fibroblast proliferation and migration, extracellular matrix deposition along with collagen deposition.

    04:39 Sorry, okay.

    04:41 Proliferation...

    04:45 angiogenesis, fibroblasts proliferation and migration.

    04:51 Before that you get the extra cellular matrix coming in which acts as a scaffold, and the fibroblasts are lying in that.

    05:00 Okay? This essentially forms a granulation tissue.

    05:05 The last phase of this is your epithelialization.

    05:08 The epithelium from the epidermal cells coming in, closing the wound.

    05:13 So, this is your third stage of the wound healing.

    05:16 And the final stage is remodeling.

    05:19 So, now you have got a granulation tissue.

    05:22 Now, the wound has to shrink, shrink, shrink, shrink, shrink and became a scar.

    05:27 So, if it all goes smoothly, you end up with a nice linear scar.

    05:32 But if you have any imbalance between proliferation, and degradation of the collagen you will end up with a hypertrophic scar or a keloid scar or a non-healing wound.

    05:45 Okay.

    05:45 Another question they will ask you is MMP? What is MMP stand for? Matrix metalloproteinases.

    05:55 So, the matrix metalloproteinases, and the the opposite of this tissue inhabitants of metalloproteases, these two enzymes, pretty much breaks down all the collagen.

    06:10 So, the collagen is forming.

    06:12 If the collagen continues to form without any inhibition, it will become overgrown scar.

    06:19 That's the keloid or hypertrophic.

    06:20 So, these are secreted into the wound to balance it out.

    06:24 And the final phase is remodeling phase, where all this thing is happening.

    06:31 So how long does a remodeling phase last? It starts from approximately...

    06:36 When, when does the remodeling phase start? Approximately, two weeks to around six weeks, but it can go all the way up to year.

    06:44 So, even after 1 year, the scar has achieved only about 80% of its normal tensile strength.

    06:51 A scar will never achieve a hundred percent of the strength.

    06:55 Even after one year, it's only about 80% strong.

    06:59 Okay? So, that is all part of the remodeling phase.

    07:02 So, the remodeling in the scar maturation is one phase.

    07:06 So, hemostasis, inflammation, proliferation and remodeling.

    07:12 These are four phases of wound healing, and they'll ask you what cell type is involved in each.

    07:19 Okay, then the types of wound healing.

    07:21 So if you have a linear scar, what do you do? You approximate with the wound, either with sutures, staples, glue, etc.

    07:31 And that is healing by primary intention.

    07:34 But imagine if that is a dog bite or a human bite, you leave it maybe for 24 hours, 48 hours and close it by delayed primary intention.

    07:45 Now, there is a question or it's been asked before, in the UK, so many of you will know in specialized orthopedic or plastics units.

    07:53 We are more than happy to excise it primarily, and close it even if it is a dog bite.

    08:00 So, it used to be the norm that a dog bite, you never close it in the first 24 hours.

    08:05 But imagine a child, two-year-old, with a bite in the face, small bite.

    08:10 You don't want to take the child back to theater after 48 hours for a GA.

    08:15 So, the safest thing to do is you excise the wound, clean it up and close it primarily.

    08:22 So, you're converting it that in do a primary intention wound.

    08:29 You do it in adult as well, you can do it on adult as well, but the classical example is in a child, what you do? Yeah.

    08:36 So, traditionally, you leave to heal, leave it for 24-48 hours and then close it.

    08:43 So, that is healing by delayed primary intention.

    08:46 Okay, the second other type healing by secondary intention.

    08:50 When do we do that? Infected wounds, okay, give me some clinical scenarios.

    08:57 Abscess.

    08:58 Abscess, very good.

    09:00 Ulcers also pressure ulcers.

    09:03 A laparostomy wounds, which you really can't close it.

    09:07 The only option you have is to put dressing on, put some back on, and help it to granulates and close it from the edges.

    09:16 Now, the cell type which is involved in that type of feeling is myofibroblasts, not the fibroblasts.

    09:22 The myofibroblasts is a type of fibroblasts which helps in wound contracture.

    09:27 Those wounds, the scarring is bad because it heals by contraction not by the normal healing process.

    09:34 Okay, what's other type of healing? So, we discuss true healing by primary intention, delayed primary, healing by secondary and healing by one more.

    09:47 Yeah, go on, before that.

    09:49 Let's say, if somebody if you sustain an aberration, like this just scrape, how does it heal? Does it go through all the wound healing status? There doesn't scar.

    10:01 Okay, another example, split skin graft, that heals without a scar.

    10:06 How does that happen? Yes, healing by re-epithelialization.

    10:15 So, that is another phase of type of wound healing, where it is not going through any of these stages because all the adnexal structures are still intact.

    10:24 All you have done is shaving off the superficial breath epidermis, maybe a little bit of the dermis, but all your sweat glands, hair follicles, the rest of the dermis is all intact, so they just re-epithelialized.

    10:38 So, that's why they heal without a scar.

    10:42 So, that is the fourth of the type of wound healing.

    10:45 Okay? Healing by re-epithelialization.

    10:47 The classically seen in operation, split skin donor graft site.

    10:55 Okay.

    10:56 So, that's that and what about the other questions you are asking is related to do the reconstructive ladder.

    11:03 So, you have...

    11:11 let's say somebody had an abscess, in the chest and it ends up with this sort of wound.

    11:21 Okay? You have is just a healthy normal fit and healthy patient.

    11:28 What are your options to close this? Primary closure.

    11:32 Okay, so that's your simplest form of healing by primary intention or primary closure.

    11:41 Okay, I'm still telling you I can't do it because it's too wide what's your next option? Delayed primary closure fine, but again delayed primary closure has contracted it, but still not good enough.

    11:54 I still can't close it, it's still big.

    11:57 One minute, just one minute before that.

    12:00 Before that, you can try the secondary intention is the lowest form because you can put a back on it and go for this closure, but that is not ideal.

    12:09 This will end up with a bad scar.

    12:11 Okay, so healing by secondary intention is probably the lowest form of closure is more of a primitive, form if you look at in an evolutionary perspective.

    12:20 If you are got bitten by a tiger for million years ago, you didn't have any of these options.

    12:26 You left it to heal by secondary intention, so that is a most primitive form.

    12:31 Slightly advanced is primary closure, then you said delayed primary.

    12:40 Before that, before the flap, correct, skin graft.

    12:43 Okay, now...

    12:46 how do you decide, she mentions local flap, you mentioned skin graft.

    12:51 When do you decide skin graft to local flap or graft? Well, it seems on the chest here.

    13:07 You can put the split skin on the dermis.

    13:09 What are they contraindications for a split skin graft? Bare tendon, bare tendon, barebone.

    13:17 So, if you if you don't have the periosteum or if you don't have the paratenon, then you can't put a skin graft.

    13:23 However, if you have a exposed tendon or an exposed bone, but the periosteum is intact.

    13:29 You can put a skin graft.

    13:31 Okay.

    13:31 So, this is your absolute...

    13:34 So, for example here, let's take the same wound on the chest, is on the pectoralis major muscle, your first option will be to primary close it, delayed primary, then, the next thing you are considering is split skin graft.

    13:49 So, you mentioned skin graft that is split into full thickness, and split skin graft.

    13:55 Split is the the first option you consider because you're not leaving a donor site wound.

    14:03 So because it heals by re-epithelialization.

    14:05 You shave a piece of skin from here place it on this, that's a good option.

    14:12 Now, if this, you can't participate skin graft because let's say this wound is on the hand, where the tendon is exposed there is no paratenon, the periosteum is stripped off, then you can't put a split skin graft.

    14:28 Then you have to go for a full thickness.

    14:31 Okay, even then it's risky.

    14:35 It might not take, anything to do with a graft is dependent on recipient blood supply.

    14:43 Okay? So, you probably don't want to take any of this option, if you think, the recipient blood supply is compromised.

    14:51 What other example I gave you two, paratenon.

    14:54 No periosteum, no paratenon.

    14:57 Where else would you not use a skin graft clinically? Radiotherapy, treated areas.

    15:02 Because if you have an area treated with radiotherapy, there is no blood vessel in that area that is all dead, that's all killed off.

    15:09 So, you can't put a skin graft.

    15:11 Okay? What's the difference between a split and a full thickness skin graft? Split thickness skin graft takes only, will not dermis.

    15:20 This epidermis and different level of the dermis.

    15:23 It could have a thick skin graft or a thin one, so depends on the level.

    15:30 But the most important thing is, the donor site is left to heal by re-epithelialization.

    15:37 Full thickness skin graft, you take the whole of the dermis and the donor site is closed primarily.

    15:44 So, the common sides for full thickness graft donor sites are preauricular, post auricular, supraclavicular, and the inner aspect of the arm and as well as the groin.

    15:56 These are the common size for a donor sets of full thickness.

    16:00 For a split, it is usually that last bit of thigh buttock and the back.

    16:04 Okay, So, we come to the situation where you can't use any of this.

    16:09 That's when you go for a local flap.

    16:14 So, you have a whole.

    16:17 You can't put a graph here, you can't close it.

    16:19 Then, the only option is to do a local flap.

    16:22 So for example, what you can do is you can make this into a rhombus shape, and then you put a local flap.

    16:29 This is a rhomboid flap.

    16:32 Okay, so this goes into that.

    16:35 So here, the blood supply is taken from there and rotated and pushed in here.

    16:41 Okay, so that's your local flap.

    16:44 Now, let's say the wound is very big.

    16:47 You can't put a local flap.

    16:49 What's next option? Pedicle flap.

    16:51 So that's your classic example is mastectomy.

    16:54 Okay? So, a mastectomy say for stage 3, no, you didn't have to actually know clearance, then use latissimus dorsi muscle as a pedicle flap to cover it.

    17:08 So that is a classical pedicle flap.

    17:18 Okay.

    17:21 We'll stay on the same example.

    17:23 Mastectomy, patient is not suitable for a particular flap because of maybe because of radiotherapy, axillary node clearance, or the latissimus dorsi muscle is not big enough, whatever reason or the vessel is not big enough.

    17:37 Then you go for the free flap.

    17:44 So, this is your reconciling ladder, going from the simplest one to the most complex.

    17:50 So, the free flap for a breast, you could take from the abdomen like the in deep inferior epigastric perforator, superior gluteal artery perforator flaps or any of the perforator flaps, or any of the free flaps, but the concept is you are detaching blood vessel.

    18:07 And reattaching it.

    18:09 In these two, you're not detaching the blood vessel.

    18:13 You are just moving the blood vessel.

    18:16 Okay, and in these two, you are dependent on the recipient blood vessel.

    18:36 So in the in terms of flaps, you can be asked two flaps, you should ask about rhomboid flaps.

    18:41 Rhomboid flap is a type of local flap.

    18:44 It is the rhomboid, the angle you need to remember is, this angle is 120 degrees and this is 60 degrees.

    18:53 You know, that's the only number you need to remember 120 and 60, and shape of rhomboid and you make a flap and push it in.

    19:01 Okay, so that's a rhomboid flap.

    19:04 The other one they ask is, 'is that plasty?' Have come across, 'is that plasty?' When do you do if it's plasty? And what is it? It's okay, done it.

    19:22 You can do pretty much at anywhere but usually, you have a long scar.

    19:27 Imagine this is a very, very tight scar, and say it's on the axilla here.

    19:32 The only way to release a scar is to reorient the direction of the scar.

    19:37 Okay, so you turn the direction of the scar to slightly different.

    19:40 So, that you get much more external rotation or friction.

    19:44 So, plasty is a technique whereby that's exit.

    19:49 Okay, this is the exit.

    19:53 So, you make a incision here, you make an incision there, and then you move these flaps around, you move that flap, one flap to here.

    20:02 So are essentially reorienting the direction of the scar and you are leasing the contraction.

    20:07 So, that's the principle.

    20:11 Now depending on how you make the angle, you get more or less release.

    20:17 So, you can make a very obtuse is it or on very acute is it.

    20:25 Clearly with this you can more recruitment of tissue because you are taking more tissue and bringing it in.

    20:30 So, the answer to your MCQs will be, it is to reorient the scar as well as to release the contraction.

    20:38 Okay.

    20:38 So, this is not a type of flap but it is a type of flap, but it is that plasty is a technique.

    20:49 They may ask you.

    20:52 Okay, anything you want to ask? I think that's all about wound healing.

    20:59 Any question on those that have you been asked, have you seen any other question in this.

    21:03 You have? On what? On flap, sorry anything apart from this? No.

    21:11 Okay.

    21:11 Two things I need to cover because it always comes a bonus biopsy and the second was local anesthetic.

    About the Lecture

    The lecture Questions by Stuart Enoch, PhD is from the course Trauma and Post-OP Management.

    Author of lecture Questions

     Stuart Enoch, PhD

    Stuart Enoch, PhD

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