 Watch out, Mark is taking a pan shot. Okay, good morning. Come in Peter. Walk fast your fingers. So, let me give you a, this is our PD demonstration. This is a demonstration of the lumbar puncture. A few quick words. This is the mannequin I was talking about. This is a digital mannequin by the company called Gaumard Limited. And the so-called patient is sitting in the lying down in the left lateral position. And I'm going to demonstrate a few things on this mannequin. But first before that, let me start with a few words about the instruments that we are going to use. This is what you see in front of you is the lumbar puncture needle. Actual lumbar puncture needle. We have procured this from Alexandra Hospital. This is called the two-heed needle. If you look at this, this is the hub of the needle. This is the needle proper, which is supposed to be sterile. And we are not supposed to touch this with our finger, even though we are wearing gloves. The hemi mannequin. As I told you, it's a digital mannequin. There's a pressure recording device here. This is the inlet. Mandeep is handling. He's the CSF handler. He is pushing in the CSF. So we are using sterile drinking water for this purpose. Ideally, we are supposed to use distal water, but we don't have the distal water here. There are two things which are inserted here. This is the spinal cord insert. And inside that, there's a spinal canal assembly, which contains the CSF. When he's pushing it here, it is going to the spinal canal. And it's been designed to look very realistic. I would suggest all of you can come even closer, because you're going to see the procedure. Okay. You can come as close as you can. So, when we pierce, this has been made very realistic and lifelike in almost every situation, except a small difference, which I'll tell you later. Once we pierce the dura-arachnoid interface, you will hear and you will feel a pop sensation, which is lifelike. And that's when you know you are in the spinal canal. And that's when we remove the stillet and we see the CSF dripping out. Okay. The landmarks. You can see a shallow ridge here. So this and this, these two correspond to the highest point of the iliac crest. So therefore, when we join them with an imaginary line, that line is called the supracrystal plane. That is called the supracrystal plane. And the supracrystal plane goes exactly over the L4 spinous process. That is our landmark. So once we feel the L4 spinous process, we go one space above that, that is the L3, L4, into spinous space. Sometimes we can go one space below that, that is L4, L5, spinous. These are the usual spaces that we use. Okay. Patient is in the left lateral position. You are wearing gloves. We'll assume that you have already cleaned the area with povide and iodine, alcohol, isopropyl alcohol, etc. You have draped it and you have infiltrated local anesthesia over the skin and the subcutaneous tissue using 0.5% lignocaine. So now we are going to demonstrate the procedure. Before that, one more thing I need to tell you. Once we have entered the spinal canal and we are seeing CSF, we are sure that we have entered the spinal canal, still sometimes CSF may not come out. It happens. Sometimes what happens is a small filament of arachnoid trabeculae may block the opening. Then there are two or three things that we can do to make the CSF come out. One, in an actual living situation, we can ask the patient to cough gently. That way it increases the intrastinal pressure and CSF starts coming out. But here we cannot ask him to cough because he is not aware of it. So what we can do is, the next procedure is you can rotate the needle in its long axis. That way also it dislodges the arachnoid trabeculae and the CSF will start ripping out. And the third procedure that we can do is we can take a syringe. We can attach it because remember the stilet is already out. You can attach the needle, the syringe to the hub of the needle and you can gently aspirate. Then the CSF will start ripping out. So these are some of the procedures that we can do. One more thing, because the spaces are very narrow, normally in an living situation, what we do is we put the patient in a fetal position. That is the knees are touching the abdomen and the chin is touching the chest. That way what happens is the intrastinal spraices open up. But here we cannot do that. Quite often it happens is that as we are advancing through, the needle hits a bone. If the needle hits a bone, it is quite likely we should not proceed any further. We should not try to manipulate also. We should pull it out straight away and then again reinsert. So that is what we will be doing. If you hit the bone, we do not try to manipulate any further. So these are the few preliminaries. So when we are doing the procedure, the few things to remember. The needle, the long axis of the needle should be exactly parallel to the ground surface. In a real situation, the direction of the needle is towards the umbilicus of the patient. But here, this is one small manufacturing anomaly. It is not directed towards the umbilicus. We directed a little in the opposite direction. That is the only difference which I have noticed. But in a real situation, we always directed towards the umbilicus of the patient. The tip of the needle should hit the skin at exactly right angles. And the direction in this case is slightly opposite to the umbilicus. That is the only difference which I wanted to highlight. So let us start off. We have assumed we have cleaned and done all the preliminaries. So this is the supracrystal plane. This is the L4 spinous process. So this is the L3, L4 space. So I am going to... We are not going to touch this area. I am going to put the needle. So skin subcutaneous tissue. Supra spinous ligament. Intra spinous ligament of flavum. You heard it, you felt it. This is exactly how you would feel. I am sure I am in this space. I have not removed the stilet yet. The moment you hear and feel the pop, don't go further anymore, even one millimeter, because then you will go through. Immediately stop. And then you remove the stilet and you see the CSF dripping out. So once the CSF, you can collect the CSF for diagnostic purposes. Obviously in real life you don't let the CSF drip out so freely because you will produce low pressure headache. Remember I mentioned it yesterday. So that is why we have to put the patient flat and lift up the foot and all the rest of it. Here we can play around as much because we, Mandip has got plenty of CSF within. So we can collect the CSF for diagnostic purposes. And what is not given here to us with this model, there is a long burette which is actually the spinal manometer. It has got a three-way stopcock. We can connect it here and we can read the pressure on the burette in millimeters of water. So that way we can do the spinal manometer also, which I have told you in the class. And after the whole procedure, after you have done the diagnostics and the therapeutics, if you want to inject drugs that is therapeutic, you can inject local anesthetic agent to give regional anesthesia or you can give intraspanel injections of other agents like for example, chemotherapy agents and all the rest of it. After the whole thing is over, then we have to reinsert back the stilet. This is an important point to remember. Many of you will try to remove the needle. You will be so happy that you've got the CSF, you will immediately try to pull out the needle, reinsert back the stilet. And after you have done that, then the final step will be to put a thumb here. Give a counter pressure of the skin, otherwise the skin will tent up and there may be a subcutaneous achemosis hematoma. So give a counter pressure of the needle here and give the counter pressure of the skin here and pull the needle straight back. And after that, we put a tincture benzoin seal or autologous homographed here and you put the patient flat for 24 hours if necessary, lift up the foot tent. So that's the procedure. So all of you saw it, all of you understood it. Now, I would like all of you to one by one come here. I'm going to go that side and all of you will do it. It's not a very difficult procedure if you just pay attention to the details. Yes.