Chronic Limb Ischaemia

Welcome to First Incision, the podcast about preparing for the General Surgery Fellowship exam. I'm your host, Amanda Nikolic. Let's get started with our team timeout. Our patient today is the arterial venous and lymphatic system module from the general surgical curriculum. And the operational topic we'll be covering today is that of chronic peripheral vascular disease. Thank you.

So chronic peripheral vascular disease is what it's called in our curriculum, but more commonly I hear it described as chronic limb ischemia. And this is a condition where atherosclerosis causes stenosis or occlusion of arteries, leading to ischemia of the limbs.

Chronic peripheral arterial disease is very common, with about 15% of patients in the elderly population having some degree of peripheral arterial disease. But a number of patients will be asymptomatic with this disease. About 7% to 15% of patients who have asymptomatic peripheral arterial disease will develop intermittent claudication over five years. And of those patients who develop intermittent claudication, 5% will deteriorate.

and require revascularization and 1% to 2% will require major amputation. And just a quick definition. There are a few of these floating around but the definition I like to remember for what is critical limb ischemia or chronic limb-threatening ischemia is chronic ischemic rest pain. so more than two weeks, with ulcers or gangrene that's attributable to a proven arterial occlusive disease. So what are some of the risk factors for chronic limb ischemia?

So our curriculum wants us to know about what systemic conditions contribute to chronic limb ischemia and for us to be able to take a history of and examine all arterial risk factors. So keeping that in mind, risk factors for peripheral arterial disease include non-modifiable risk factors such as increasing age, a higher risk in the male sex than in women. Some ethnicities have higher risks of peripheral arterial disease and a family history of peripheral arterial disease.

Some environmental or modifiable risk factors include smoking, which is the strongest risk factor for peripheral arterial disease, obesity, hypertension, hypercholesterolemia, and diabetes with poor glycemic control.

The pathophysiology of chronic limb ischemia or peripheral arterial disease is the same as arterial disease found elsewhere in the body, which is that it's a consequence of atherosclerosis. Atherosclerotic plaques form within the intima of arteries because of the risk factors that we just talked about. And the pathophysiology of this is that there's a chronic inflammatory response of the arterial wall to endothelial injury.

So this endothelial injury occurs because of the hyperlipidemia, hypertension, smoking, hemodynamic factors and immune reactions and toxins. And this leads to accumulation of lipoproteins such as low-density lipids and cholesterol within the vessel wall. This then leads to platelet adhesion. Monocytes then also adheres to the endothelium and differentiate into macrophages and foam cells. And there is lipid accumulation within these macrophages, leading to an inflammatory cytokine release.

There's then smooth muscle cell recruitment and smooth muscle cell proliferation. And this results in the formation of an atherosclerotic plaque. The complications of these plaques is that they can build up to the point that they cause a critical stenosis and reduction in blood flow peripherally.

And when the reduction in blood flow leads to tissue perfusion, which is not able to meet the increased metabolic requirements of a muscle group, then this leads to intermittent claudication. So in a resting state, patients may... not have pain, but when they try to exercise or walk, then the blood vessel is not able to open up and provide additional blood supply, so they get ischemic pain.

And then another complication of atherosclerosis is that the plaques can rupture and this leads to secondary thrombosis on that exposed plaque. And this can cause a sudden complete occlusion of the vessel. And this leads to critical limb ischemia with rest pain, tissue loss and gangrene. And this is because the... Blood vessels obviously blocked, so there's no distal perfusion and therefore the basic metabolic requirements of the tissues are not being met, resulting in tissue death and gangrene.

So how do patients with peripheral arterial disease or chronic limb ischemia present? So there's a number of different clinical syndromes that patients can present with. The first of these is intermittent claudication, which I've mentioned, which is where there's pain on walking in the muscle groups that are distal to the site of obstruction.

and this pain is brought on by exertion and usually relieved by rest. They might present with an ache, a cramp, or a tightening of the muscle group, and this usually forces patients to stop. walking or stop the exercise. And this is often the first symptom of peripheral arterial disease. The most common site is usually the calf, but it can occur in the hip or in the buttock.

Another way that peripheral arterial disease can present is with critical limb ischemia pain. And this is pain at night or at rest. And usually it's pain in the foot at night that's sufficient to disturb the patient's sleep and is relieved by hanging the leg out of the bed or by walking around. Patients' presentations may be different depending on the degree of the stenosis as well as the level of the disease. And chronic peripheral vascular disease...

plaques are often described by their anatomical distribution. So they're often termed as either aortoiliac disease, femoropopliteal disease, or tibial disease. And they can be a combination of these locations as well. When taking a history from a patient presenting with chronic limb ischemia, you're going to want to ask them questions about their presentation. So if they've presented with...

of claudication, you're going to ask them about that. And there is a classification system that classifies the different degrees of claudication. And this is called the Fontaine classification system, F-O-N-T-A-I-N-E. And this classifies claudication based on the distance at which it comes on. And so stage one is asymptomatic, so no claudication. Stage two is split up into 2A and 2B.

2A is where there is intermittent claudication after more than 200 meters of walking. And stage 2B is intermittent claudication at less than 200 meters of walking. Stage three is rest pain, especially at nighttime. And stage four is ischemic ulcers or gangrene in the limb. Your history should also ask about potential sites of vascular insufficiency elsewhere, so whether they get pain when using their upper limbs. In men, whether they have erectile dysfunction.

and also whether they have any postprandial abdominal pain that may indicate chronic mesenteric ischemia. You're also going to ask about risk factors for peripheral arterial disease, which we've already talked about. So a full history of these risk factors would include asking about smoking, diabetes, hypertension, dyslipidemia. chronic renal failure, drugs and family history.

as well as past history of any other cardiovascular-related diseases, such as ischemic heart disease with stents or bypass, cerebrovascular disease such as strokes or TIAs.

Moving on to how you would examine a patient presenting with potential limb ischemia or peripheral arterial disease. So first you'd start with their observations, so looking at their blood pressure and heart rate. You'd look generally at their body mass index and also for any signs of risk factors for atherosclerotic disease, such as cigarette staining on the fingernails or xanthalasma around the eyes.

You're going to check the blood pressure on both arms and also palpate the radial and brachial arteries, as well as perform a cardiac and pulmonary examination, so listening to the heart and the lungs. You can also auscultate the neck and feel and auscultate the abdomen and the groin for aneurysms or for bruise. So then you're going to turn your attention to the legs and...

You're going to start with your general inspection. So you're going to have a look for any scars from previous surgery, any previous amputations, as well as looking at the skin colour for any colour changes. Color changes that may indicate ischemia or peripheral arterial disease include a red color of the skin, which could represent vasodilatation of the microcirculation due to tissue ischemia.

In advanced ischemia, the skin may be white and look pale. And in irreversible ischemia, you get fixed skin staining with a purple or blue appearance. You also want to have a look for trophic changes. So in arterial disease, you'll get a shiny appearance to the skin with loss of the hair and you may see muscle wasting. You then also want to look for evidence of tissue loss, so gangrene, ulceration, previous amputations, as I've mentioned, and specifically arterial ulceration.

Arterial ulcers are found in the poorly perfused area over pressure points, including the lateral aspect of the foot and over the medial and lateral malleolais. Arterial ulcers are usually punched out and well circumscribed. And they usually don't have any granulation tissue in the base, usually a thin layer of slough. And you may be able to probe some bone underneath them. The last thing to look at in terms of inspection is to do a burgers test. Burgers, B-U-E-R-G-E-R.

And this is looking for the angle that you have to lift the leg up straight before the perfusion drops and it becomes white. So in a normal leg, you can raise it up to 90 degrees and it will still remain pink and perfused. If this angle is reduced, so less than 20 degrees, this is very severe ischemia. And if it's somewhere in between, this may indicate less severe ischemia.

And you can complete this test by then dropping the leg over the side of the bed. And initially it will become quite a deep purple red color because of the reactive hyperemia to the ischemia that it's experienced while you were lifting it. up in the sky. So the next thing you're going to do on examination is to palpate. The first thing you want to do is palpate all of the peripheral pulses and this includes the aorta, femoral, popliteal.

dorsalis pedis and posterior tibial. And you want to say whether it's present, reduced or absent. You can also feel the temperature of the limb. So a poorly perfused limb will be cool compared to the other limb. And you can test for capillary refill, which will be reduced in a poorly perfused limb. You can then auscultate over all of the vessels as well, listening for a brewery.

The next thing you can do on examination is measure the ankle brachial index. And this is a measurement that compares the systolic pressure of the brachial artery. to the systolic pressure of the dorsalis pedis and posterior tibial using a blood pressure cuff around the ankle. And typically this test is done using a Doppler probe to identify the systolic pressure as you release the blood pressure cuff. And you use the ankle pressure over the brachial.

pressure and this will give you the ankle brachial index. And if it's less than 0.9, this is suggestive of peripheral arterial disease. And if it's less than 0.5, this suggests critical ischemia. This can be affected by calcified vessels in the calves, which is more common in patients with diabetes. So that's something to be aware of. The other thing that can be done is toe pressures. And this is a good alternative if there are calcified vessels.

And it's done using a really, really tiny blood pressure cuff that goes around the toe. And if the toe pressures are less than 30 millimeters of mercury, this is consistent with chronic limb ischemia. And usually an ulcer isn't going to heal unless the toe pressures are more than 40 millimeters of mercury.

In terms of your examination, there's another classification that we can talk about called the Rutherford classification, which is a little confusing because there's also a Rutherford classification for acute limb ischemia, but this is the Rutherford. classification for chronic limb ischemia. And it's essentially the same as the Fontaine classification from zero to four. So zero is asymptomatic

One is mild claudication. Two is moderate claudication. Three is severe claudication. And four is ischemic rest pain. But then the examination comes into it where a Category 5 Rutherford chronic limb ischemia is where there's minor tissue loss with a non-healing ulcer, gangrene and diffuse pedal ischemia. And a Rutherford 6 is where there's major tissue loss extending above the transmetatarsal level or with frank gangrene.

The other classification system to be aware of for chronic limb ischemia was published in 2014 by the Society for Vascular Surgery. And the article is titled, The Society for Vascular Surgery Lower Extremity Threatened Limb Classification System. And it's a risk stratification based on wound. ischemia, and foot infection, also called the Wi-Fi criteria. So W of the Wi-Fi is wound, ischemia is eye, and foot infection is the Fi of Wi-Fi.

And the Wi-Fi system basically looks at each of these areas and gives a score out of 0 to 3 for each of these. So starting off with the W for wound, zero is no ulcer and no gangrene. One is a small shallow ulcer on the distal leg or foot with no exposed bone. Two is a deeper ulcer with exposed bone, joint or tendon or gangrene limited to the digits. And three is extensive deep ulcers involving the forefoot and or midfoot.

or deep full thickness heel ulcers with calcineal involvement, or extensive gangrene involving the forefoot or midfoot, or full thickness heel necrosis with calcineal involvement. For the eye part of Wi-Fi, this is for ischemia. And this is usually done using the ankle brachial index. So grade zero is an ABI more than 0.8. Grade one is a ABI of 0.6 to 0.8. Two is an ABI of 0.4 to 0.6. And grade three is if the ankle brachial index is less than 0.4.

And then the last one is foot infection. And it's graded as zero for none, one for mild, two for moderate, and three for severe, which might be limb or life-threatening. And they say that the clinical manifestations of infection are local swelling or induration, erythema around the ulcer, tenderness or pain, warmth, and purulent discharge.

I think I'll probably just remember the Rutherford classification of chronic limb ischemia that just makes five minor tissue loss and six major tissue loss. But I think it's worth knowing a little bit about the Wi-Fi and definitely that's how vascular surgeons can... communicate with each other about chronic limb ischemia.

So let's move on to talk about investigation for a patient presenting with peripheral vascular disease or chronic limb ischemia. So we've already talked about history and examination, which is going to give you a lot of information. But there are a number of different investigations that can be used to look at the location of the lesion as well as the degree of the stenosis. So non-invasive options include an ultrasound, and you'd be asking for an arterial Doppler ultrasound.

On a Doppler ultrasound, they look at the waveform to determine what the potential degree of stenosis is. So a normal waveform is triphasic due to elasticity in the arterial wall. A biphasic waveform indicates distal to a moderate stenosis and a monophasic waveform suggests a stenosis of at least 70%.

Duplex ultrasound is first line in most institutions, and it is a really important non-invasive imaging modality that helps to confirm and also assess the severity of the peripheral arterial disease. It also helps you identify the individual anatomical locations of any potential stenoses. The other thing that you get on a duplex ultrasound is the peak systolic velocity in centimeters per second.

and usually is measured just proximal to a stenosis. And because the blood is being squeezed through a stenotic area, the velocity actually goes up. So if there's a two times increase in the peak systolic velocity, then that suggests a 50% narrowing. And if there's a four times increase, then that suggests a really high grade stenosis.

And distal to the stenosis, the waveform usually changes shape due to dampening, and this has a reduced peak systolic velocity after the stenosis. So it can give you really good ideas about where the stenosis is and how significant it is. it is. Some potential issues with using ultrasound is that it's very difficult to view the iliacs and the aorta due to overlying bowel gas and tortuosity and also because patients breathe.

And also deep calf vessels may also be difficult to image. And they can also be difficult through vessels that have lots of calcification. So another option is a contrast enhanced CT angiogram.

Unfortunately, a lot of the patients presenting with peripheral arterial disease also have renal failure. And so you may not be able to give contrast. But if you can... do a CT angiogram, this can give you really good information in addition to the ultrasound for patients who are having surgical planning and also can give you good information about the aorta and the iliacs.

In some countries, they use MRI angiography, which obviously doesn't use any radiation and can be a really good study, but I just don't think we use that that often in Australia. Those are the non-invasive tests that we have to look at peripheral arterial disease and chronic limb ischemia. The invasive test that we have is digital subtraction angiography.

which really is the gold standard investigation. It gives you great images and also gives you the ability to actually perform both diagnostic and interventional procedures in the same setting. It is, however, an invasive test requiring cannulation of a vessel in order to put in the contrast and so it's not recommended for use just for investigation. and is reserved mostly for where there's an intention to proceed to some sort of endovascular intervention.

Some potential risks or complications of this procedure is that you can get a pseudoaneurysm or hematoma around the puncture site. It obviously uses a contrast medium, which has risk of allergy or renal impairment. The vessel can be dissected accidentally due to the puncture or wiring going down the vessels, can lead to infection, a fistula, embolization, and obviously has some radiation associated with the x-rays.

And it's expensive, often requires a day case bed and uses stuff that could be used for an interventional procedure. So I think in my exam, if I get asked what investigations I'm going to do, I'm going to start with a duplex ultrasound first. And then proceed to a CT angiogram or an MRI angiogram as the next investigation if further imaging is needed before revascularization.

I'm really going to leave the catheter angiography or digital subtraction angiography is another term for it for the vascular surgeons at the time of any endovascular intervention that may be required.

So what is the management of chronic peripheral arterial disease or chronic limb ischemia? So first is medical management. So this includes modifying patients' risk factors. And this is important not just for managing the... peripheral lesion but also because these patients have an increased risk of stroke, fatal MI and an increased risk of death from any cardiovascular cause if you've diagnosed them with peripheral arterial disease. So patients need...

Advocation for smoking, cessation, diet, weight management, exercise. And there's evidence that supervised exercise therapy is helpful for claudication symptoms. So this is usually a 30 to 60-minute treadmill walk per day, and they stop when the symptoms start and rest and then repeat.

are shown to improve claudication. Patients who have hypertension should have their blood pressure controlled. Blood pressure is greater than 140 on 90 in a patient who has diagnosed peripheral arterial disease needs treatment. And if patients are young, you'd usually start with an ACE inhibitor and then add a calcium channel blocker and then a thiazide diuretic. And if they're more than 55, you'd start with a calcium channel blocker.

then add an ACE inhibitor and then add thiazides and you're aiming to achieve a blood pressure of less than 140 on 90. Patients who have diabetes should have their diabetes managed. well and so you're aiming for a HbA1c level of less than 7%. The next thing to consider is medication therapy. Lipid modification with statin therapies are really important.

And statins, just to remind ourselves because it's been a while for me, is a HMG-CoA reductase inhibitor, which limits cholesterol synthesis in the liver. And it also has anti-inflammatory effects and helps to stabilize atherosclerotic plaques so that they have less risk of rupture. Antiplatelets should be started.

And these are indicated in all patients with peripheral arterial disease. You definitely start with aspirin. And there's some evidence that clopidogrel is better than aspirin at reducing strokes and also the risk of amputation in peripheral arterial disease.

Moving on now to interventional management. The principles of... intervention in peripheral arterial disease and chronic limb ischemia is to try to identify adequate inflow, provide a suitable conduit and establish adequate runoff. The NICE guidelines state that the indications for intervention for peripheral vascular disease are patients who have intermittent claudication where medical management has failed.

or patients presenting with critical limb ischemia, which if you remember from the start of the episode where we talked about definitions, critical limb ischemia is where you have ischemic rest pain. with presence of ischemic lesions or gangrene. And it can also be defined as an ankle brachial index of less than 0.5. For these patients, there's a number of different interventional options.

And the choice of which one you would use when I think is quite complicated and probably above the level of what we would need to know for the exam. But in general, I'll just run through what the options are. So first option are endovascular treatments. Endovascular treatments include balloon angioplasty, so ballooning open a stenosis, use of a self-expanding metal stent,

or using a covered stent graft, like in a AAA repair, for example. Risks of the endovascular options include bleeding from the puncture site or formation of a pseudoaneurysm, dissection, embolising atherosclerotic plaques down the vessel, causing a trash foot, for example, or complications related to the intervention like stent failure or misplacement. infection or stents can also occlude and patients do need contrast for this procedure so you can get contrast related nephropathy.

Options for open surgical interventions essentially include bypass grafts, which can be done with vein grafts or with a prosthetic graft material. And the choice of what particular bypass you do really depends on the anatomical distribution and location of disease.

Some of the options for iliac disease or distal aortic disease include an aorto-bifemoral bypass or axillobifemoral bypass as a last resort. Patients can also have... iliofemoral bypasses if they have iliac disease or an iliofemoral crossover if the affected limb has no inflow but the contralateral limb is relatively disease-free. And there can also be a femoro-femoral crossover for that same indication.

If you have disease in the common femoral artery, this is almost exclusively managed with open surgery because it's difficult to use stents in this location. For the profunda femoris, Often you do an endarterectomy and a patch repair and that can often be done in combination with bypasses like an aorto-femoral if there's an inflow problem or a femoropopliteal bypass if there's an outflow issue.

For superficial femoral artery disease, surgical bypass is often done. And this is typically a femoropopliteal bypass using something like a autologist vein graft or a synthetic. graft and the common ones that are used are PTFE or Dacron. And percutaneous treatment isn't used as often in a superficial femoral artery disease. Popliteal artery disease, because of the biomechanical stress put on the knee during flexion and the location is often difficult to manage.

percutaneous treatment usually isn't a good choice because stents don't really bend very well. So usually bypass is used for popliteal disease. And for infrapopliteal artery disease, which is common in diabetics, so smaller vessel disease, intervention is really performed for critical limb ischemia only, not for claudication. Usually things like balloon angioplasty, atherectomy, stents or bypasses are used in these situations.

As I mentioned, the decision making for what procedure to do and what situation is pretty complex and hopefully is in the realm of the vascular surgeon and not the general surgical exam. But they do talk about us. recognizing the indications for conservative versus interventional treatment, and also differentiate between radiological and surgical options and being able to discuss their limitations in our curriculum.

The last surgical option I wanted to discuss is major amputation. And the goals of major amputation or when you might use it is if there's extensive tissue loss. for relief of ischemic pain that can't be treated with revascularization, to achieve primary healing of wounds. and to preserve an independent ambulatory status for patients who are capable. So indications are things like pedal gangrene, overwhelming sepsis from the foot.

when all other treatment options for revascularization have been exhausted, in the setting of a late presentation of acute on chronic limb ischemia with a dead leg, or in patients who are non-ambulatory. The choice of whether you perform a below knee amputation or an above knee amputation depends on the patient's ability to walk, as well as what the perfusion is of the knee. Because if you have no perfusion below the knee, a below knee amputation isn't going to heal.

So both below knee and above knee amputations are in our operative does section of our curriculum. So I just wanted to run through these two procedures. So starting with a below knee amputation. I would perform a Burgess-style BKA with the posterior myocutaneous flap based on the rule of thirds. So I do preoperative marking and I aim for the bone transection to be... eight to ten centimeters below the tibial tuberosity. So I start by marking the skin at that level just on the anterior shin.

And I measure the circumference of the leg at this level and divide this measurement into thirds. I've used my marking on the anterior skin at the level of my bone transection and a distance of a third of the diameter of the leg, extending both medially and laterally. So I've marked out two thirds of the circumference of the leg. I then mark the posterior flap and I use the distance below the tibial incision.

to be a third of the diameter of the leg distance. And I use a gentle curve to incision heading towards the medial and lateral malleoli. And then I join that posteriorly. I then prep and drape. And I start by incising the skin and I divide the skin and subcutaneous tissues with diathermy, progressively obtaining hemostasis as I go. I ligate the great saphenous vein and nerve with a tie, and this will usually be found in the anteromedial portion of the incision in the superficial tissue.

I then incise the fascia of the leg in the same pattern as my skin markings and I do this medial to lateral. And as I'm entering into the lateral compartment fascia, I'm going to encounter the superficial perineal nerve. It should be located between peroneus longus and brevis. And distal, it pierces the fascia and goes from the lateral to the anterior compartment. So I identify it and I draw it down and transect it as high as possible.

I then elevate the muscles of the anterior compartment over Robert's clamp and I divide them slowly with diathermy, ensuring I have good hemostasis. I then identify the anterior neurovascular bundle, which I'll find on the interosseous membrane. And this is the anterior tibial artery and the deep perineal nerve, which is within the anterior compartment. And I divide this between clips and transfix it with a 2-O vicryl. I then...

Identify the fibula and I use a diathermy to clear adherent muscle to the fibula at the point of my transection. While I'm clearing the muscle, I'm mindful that just behind the fibula is the perineal vessels, which runs alongside the medial border of the fibula deep to the tibialis posterior. And so make sure that I don't damage that at this point. And I use a periosteal elevator to strip the fibula cranially. And then I divide it with bone cutters or a periosteal saw.

perpendicular to the long axis of the bone and I do this just one to two centimeters above the level of the skin incision or the level that I'm going to cut the tibia so it's just a little bit shorter. My next step is that I aim to divide the tibia. So I'm again going to use diathermy to... come down onto the bone itself and then use a periosteal elevator to clear the tibia of muscle and also to incise the interosseous membrane.

I pass a Roberts clamp under the tibia and pull a clean pack through underneath in order to protect the tissues behind it and sweep the muscle towards the knee in order to clear the surface of the tibia completely. And then I use an electric saw to divide the tibia initially at a 45 degree angle anteriorly prior to dividing at 90 degrees. So I start.

45 degrees so that it's sort of a not a straight cut through the front part of the tibia and then I go at 90 degrees to finish the division and then I use a bone rasper to smooth the edges of the tibia. The next step is to create a posterior myocutaneous flap. And so I use a scalpel and fillet the posterior and perineal compartments off the bone and I amputate the leg.

And when I say fillet, I mean that I sort of start at the bone level and I shave down towards the skin so that there's still some muscle attached to the skin flap. In the muscle bulk, I'm going to go through the perineal artery and the posterior tibial neurovascular bundles.

They should be found in the same plane between the soleus and the deep flexor group of muscles. So I identify these, clamp them individually and suture ligate the neurovascular bundles. Again, pulling gently down on the nerves and dividing. them cleanly and allowing them to retract up into the soft tissue. I routinely excise soleus because it won't really have a good blood supply anymore.

And I try to identify a plane between the gastrocnemius and soleus muscle so that I remove all of the soleus muscle bulk off the flap from the level of the tibial division downwards. The short saphenous vein is found superficially in the posterior midline. So when I remove the leg and I'm...

filleting off the skin. I'm going to identify it there and make sure that I control it and it will be accompanied by the seural nerve which again I'm going to draw down and divide. Now I ensure that I have good hemostasis. And I have to now secure my posterior flap over the bone. So again, I check that there's no spots on the bone that need to be rasped down with a rasper so that they're nice and smooth.

And I'll usually at this point put a nerve catheter up to where the tibial nerve is and also bring a drain through the muscle laterally that will be sitting in the space underneath the flap. And then in terms of closing the flap, I close two fascial layers. So the first thing that I do is that I bring the gastrocnemius fascia over the top of the tibia. And I secure this to the periosteum of the tibia. And usually I'll use a number of figure of eight vicryl sutures.

And then after I've done that, I use the fascia of the posterior flap, the superficial fascia, and I bring that over and I sew that to the fascia of the anterior compartment muscles. So this is closing fascia to fascia. And I might need to trim the posterior flap and make sure that it's gently rounded so that it does meet the anterior skin incision. I then close the skin with interrupted 3-0 proline.

mattress sutures and I put local anaesthetic into my nerve catheter as per the anaesthetist. My dressing for the wound is usually Jelinek gauze, further gauze over the top of that. And then I'll use a soft band and a crepe. And then I'll use a pre-made amputation elastic sock, which I'll put over the area. And then I'll usually make a plaster of Paris cast at the time of the surgery that will help.

control post-operative edema and protect the stump. And it's really important to make sure that patients post-operatively don't flex the knee as this can leave. to flexion contractures of the knee and difficulty with mobilization post-operatively. Usually I won't sew in the nerve catheter or the drain so that if these need to be removed... before day five which is when I do a stump check they can just be pulled out from under the dressings.

So the next operation I'm going to go through is an above knee amputation. And again, I preoperatively mark the limb. And I'm going to plan for the location of the division of the femur at the junction between the middle and distal thirds or about 10 centimetres or a hand's breadth above the patella. And based on this incision point, I mark out a transversely orientated fish mouth incision. So your lateral points of your fish mouth are going to be at your planned level of your femur transection.

And then if you measure out about a quarter of the leg circumference at that level down from that point, then. in the midline of the leg, I don't know if I'm explaining this very well, but you can look up a picture. So from your level of femur transection, a quarter of the leg circumference distally towards the patella, that point is where your lowest part of your fish mouth.

mark is going to be and so you make a curved incision from your lateral points at the level of the femur transection towards that point a quarter of the leg circumference distance down towards the knee and you do the same posteriorly but a little bit longer for your posterior flap. And I position the patient's supine and I will use a 2 and a K if they're sufficient length.

And so I start by dividing the skin with a knife and then use diathermy to incise through the fat and the fascia in the same line as my skin incision. I need to ligate the great saphenous vein, which is going to again be encountered superficially in an anteromedial location. You then divide the muscle in the line of the flaps using diathermy.

starting with the anterior and medial compartments, and you extend this all the way down to the femur. As you're doing this, you need to identify some structures you're going to go through. So you identify the femoral artery and vein, which you're going to find behind the medial intermuscular septum or behind the sartorius.

And you clamp these with Robert's clamps, divide them and suture ligate them, ideally separately if you can with a 1-0 vicryl. You also want to identify the femoral nerve and ligate it with a fine suture and then cleanly cut it. as you're pulling it down in order to allow it to retract back up into the tissues.

And you'll also find the smaller profunda femoris artery, which is going to lie between the vastus and adductor magnus, close to the medial side of the femur. And you want to again clamp and divide this. Once you've divided all the muscle, you are down to the femur and you need to clear the femur of soft tissue at the level of your amputation. And so you can use a diathermy and then use a periosteal elevator to completely clear the femur.

And you divide the femur with an oscillating saw. And you can again bevel the edges anteriorly at 45 degrees and then smooth the bone edges with a rasper. Behind the femur after you've divided it on the deep surface of the adductor magnus is the sciatic. nerve and you should be able to palpate this between your fingers but you may have to open up the fatty tissue with scissors to find it and again you identify it mobilize it pull it down

ligate it and divide it, allowing it to spring back up into the tissues. You then divide any remaining soft tissue and muscle all the way down to your posterior skin flap that you had marked out. At this point, I will take down the tourniquet and obtain hemostasis and irrigate the area thoroughly. Again, I'll place a nerve catheter next to the sciatic nerve. and a 15 French Blake strain, which will come out laterally.

Now you're going to close the skin flaps over the bone. And again, you want to perform a myodesis. So you're going to sew the muscles of the posterior and medial compartments to the periosteum. of the anterolateral femur. And then you're also going to... Pull the quadriceps muscle over the distal end of the femur and suture this to the posterior aspect of the femur. And you want to do this with the hip in full extension.

And then once you've done this, you then flex the hip to check for tension on the muscle and the skin. And if there's tension, then the femur should be shortened further. You then close the subcutaneous tissues and superficial fascia with a 2-O-vicryl. And again, close the skin with 3-O-proline mattress sutures. Again, I use the same well-padded compression dressing on the stump to make sure that it's protected and to reduce edema.

And that completes this episode on chronic limb ischemia. Please remember to rate, review and subscribe to the podcast. It makes it easier for others to find and I do love reading your reviews. It's time to close up. Thanks for listening to First Incision. If you have any comments or feedback, send us a message at firstincisionpodcast at gmail.com or follow us on Instagram at firstincision. Happy studying!