Spinal Anesthesia for Ambulatory Hip and Knee Arthroplasty Procedures

CHAPTER 1

Hi, I am Bruna Oliveira. I'm an anesthesiologist at Massachusetts General Hospital and today, we're gonna be filming spinal anesthesia for hip and knee arthroplasty procedures for ambulatory surgery. Before we start the procedure, we see the patient's consent, then we place an IV for the procedure. Prior to walking back to the room, we start some mild sedation. When the patient gets in the room, we have two options for positioning. After the monitors go on, the patient can be in the sit up position, which is what we're gonna see in the videos today. And lateral decubitus is also an option for patients that are not able to sit up. Once the patient is positioned, we do a safety pause to make sure that we are operating on the correct side. We check on allergies and check for any blood thinning medications and make sure that platelets and PTT and INR are within our guideline range for the procedure. So once all the checklist is checked, we proceed with cleaning the patient's back with a sterile solution. We put a sterile drape on the patient's back and then we start with the numbing medication. We usually use lidocaine. We can do this procedure that we're gonna see in the videos today. We're gonna use the landmark technique. The landmark technique is preferable in this situation because it's efficient and it doesn't require additional equipment like ultrasound or fluoroscopy that might not be available in every hospital setting. So once the patient is numb, we go ahead with the introducer needle and then the spinal needle. Once we find the intrathecal space, we get the local anesthetic, which in this case is gonna be bupivacaine, 0.5% isobaric, and we gently inject on the patient. Once the spinal procedure is done, we start positioning the patient for the procedure and at the same time, we start giving the patient sedation. So after the mild sedation for the spinal procedure, we proceed with the heavier sedation, which we use propofol for.

CHAPTER 2

So here we have our standard spinal tray. Inside of it, we have an introducer needle, 20 gauge, and we also have the spinal needle, which is a Whitacre 25-gauge, standard size. Other than the Whitacre, we have other types of spinal needle. We have the cutting and the non-cutting spinal needles. So the Whitacre is non-cutting. This one is Sprotte, which is a non-cutting needle as well. That's preferable 'cause it causes less damage to the dura as we try to enter the subarachnoid space. So those are the preferable ones. And here, we have the Quincke needle, which is a cutting needle. You can see that the tip has this like edge and it goes through the dura and it cuts it. So, we prefer not to use this. And as you can see, this is a 22-gauge needle, which is a bigger needle. So we try to use the smaller gauge and the non-cutting needles.

CHAPTER 3

The next thing you're gonna feel is cold soap on your back. This is just a sterile soap to keep everything clean, okay? Second time. There we go. And the next thing you're gonna feel is a sterile drape. It's like a shower curtain that will go on your back as well, okay? I'm gonna finish setting up the kit. So here we have lidocaine 1% that's gonna go on the skin. I'm gonna label it. I'm gonna start preparing. This is our introducer needle. It's a 19-gauge needle that helps us go through the skin. This is the glass syringe where we're gonna have the medication. This is bupivacaine isobaric 0.5% and I use about 1.5 cc of that. Make sure that there are no bubbles inside. And this is our spinal needle. This is a Whitacre needle, 25 gauge, it's a non-cutting needle, which is preferred for these kinds of procedures.

CHAPTER 4

All right, so the next thing you're gonna feel is a pinch and burn, okay? This is just a lidocaine. So here's a landmark technique. We feel for the spinal crest and we pretend there is a line here. It's gonna leave us at L4-L5 ideally. And then you try to palpate for the spinal processes. Some patients you can palpate and then you just have to put a little bit of pressure. Some, you can't. But the idea here is to be on midline. All right, pinch and burn. One, two, three, pinch. You create a skin wheal and then you go in. What I do with the local needle is I try to create a 3D image in my head of what the spine is gonna feel like. Try to feel for spinous processes.

CHAPTER 5

Once it's nice and numb, we're gonna use the introducer needle. It can go all the way in. And the goal of the introducer needle is just to help us get this needle through the skin and subcutaneous tissue.

CHAPTER 6

So here, once the needle goes in, we're gonna start feeling a difference in tissue. We actually landed right at the space. So we go through supraspinous, interspinous, ligamentum flavum, and then we land in the subarachnoid space.

CHAPTER 7

And here we have CSF that is flowing pretty well. You attach the needle, make sure it's nice and tight. You pull back on the plunge gently to make sure you have CSF free flowing. And then you start injecting gently. Check one more time. So, done, and then you remove everything altogether.

CHAPTER 8

Now we have the patient sitting up. We have him all monitored. The first thing we're gonna do is clean his back. We are gonna palpate his iliac crests to be at the level five or four of the lumbar spine. You're gonna feel some cold soap on your back. And we're gonna do it a second time. He has received mild sedation prior to the spinal placement. I'm gonna place sterile gloves. And the next thing you're gonna feel is a plastic drape going on your back, okay? It's just to help everything to stay nice and sterile. So we are gonna use the lidocaine. I'm gonna try to identify spinous processes here. It might be a little challenging to palpate, but let's imagine this is midline. So for this procedure, I'm gonna use the paramedian technique. So if this is midline and this is spinous process, we are gonna go like a centimeter to the right. Pinch and burn. And try to locate lamina here. Then we are gonna place the introducer needle. And then we're gonna put the tip of the needle towards what we think midline is. Get our spinal needle. And then the introducer already went through skin, soft tissue. Now we're gonna go through the ligaments. And as you progress, it's good to check for CSF just 'cause the resistance with this small needle is not very easy to feel. Always anchor your hand on the patient's back so you can have support. And you can feel the changes in resistance from the tissues that we're going through. So this is bone. When you feel bone, it's like you can't really progress your needle anymore, so you have to redirect your introducer and your needle. This is bone again. And then in your head, you start drawing a 3D picture. So that was bone, very shallow. So this is the spinous process. Bone again. And you keep re-approaching until you find a clear path. This is, oops, needle bent a little bit. Can you push your lower back towards me a little bit? The other way? The other way. That posture, perfect, this is great. This is spinous process. I'm just gonna go to a different level now. So here we had spinous process. I'm just gonna go a level up, little pinch, little bit of burn, and then we're gonna repeat the same thing all over again. So here, I'm feeling bone. This is the spinous process. And this is clear. I'm trying just to find a clear path with this needle. Go through, this feels pretty engaged, meaning we are on ligament now. And then you start checking for CSF as we go. So we're in the right place. You can see CSF flowing through the needle. Hold the needle firmly and then you attach the syringe, twist it a little bit clockwise to make sure no medication is gonna drop. You can see the syringe filling up with CSF. I'm pulling on the plunge gently, confirming the location one more time.

CHAPTER 9

Post-op, things we look for after the patient is out of the room. One, the resolution of the sensory and the motor block. Make sure that there are no deficits. And one of the common but not so common complications is described in the literature of spinal anesthesia is post-dural puncture headache. It's very rare, especially in the patient population we work with for hip and knee arthroplasty, which are older patients. And it's just a headache that can happen two weeks-ish after the procedure is done and it's positional. If that happens, the patients will contact us and we will move forward with the treatment that is usually fluids, pain medications for headaches, and wait for it to resolve. And if it doesn't, there are other procedures that we can do like a blood patch that can help the patients with the pain. But again, it's very unusual that those patients will have post-dural puncture headaches, especially when we use the small-gauge needles, the non-cutting tip needles, very rare that it happens.