Hi, my name is Leslie Quint and I'm from the Department of Radiology at the University of Michigan. Today, we'll be talking about image directed tissue sampling for lymph node staging in lung cancer. These lectures divided into four parts and today will start with part one, the surgical techniques. The objectives for this lecture are follows. First, I'd like to review various methods of lymph nodes sampling that are available to us. And also, I'd like to demonstrate how imaging may help direct optimal methods of sampling and individual patients. We have lots of different techniques in our armamentarium. So first of all, we have the surgical procedures which include Mediastinoscopy, Chamberlain and the VATS procedure. Then we have the medical techniques including Transbronchial needle aspiration biopsy Endobronchial ultrasonography and endoscopic ultrasonography. And finally, we have the imaged guided techniques CT guided biopsy as ultrasound guided biopsy. So what we'll be doing today is focusing on the surgical techniques, so mediasconoscopy. Chamberlain procedure and video assisted thoracoscopic surgery. Before we really get started with the lecture, let's take a look at a case, and I'll be asking you a question. This is a patient who'd had a previous left upper lobectomy for non-small cell lung cancer. We see some post surgical findings here in the paramediastinal regions of the left lung. He was doing fine. He was on surveillance and he came back a year later full for a servaillant CT scan which we see here on our right. Notice that on this scan, there is a new, enlarged paratracheal lymph node. A PET scan was obtained which we see here on the left and we notice that the lymph node is extremely FDG avid. So we were quite concerned that he had a new area of tumor recurrence. Well, we decided we needed to get a sample of this lymph node, but before we could do that, we had to decide what station this was in. And we would say this is Station 4R, right lower paratracheal, so here is your prelecture question. If we wanted to sample the Station 4R lymph node, what would be the best way to do that? Would we choose mediastinoscopy or a chamberlain procedure or video-assisted thoracoscopic surgery? So go ahead and pick your one best answer, and then we'll get back to this at the end of the lecture. Okay, well, let's get started now with the talk and we'll be going over the three surgical techniques, starting off with mediastinoscopy. Mediastinoscopy is also known as cervical mediastinoscopy. And we're starting with this technique because this procedure has traditionally been called the gold standard for mediastinal lymph node sampling. The technique is done quite often now as an outpatient, but in some institutions it does require an inpatient stay and this is how it's done. An incision is made over here at the suprasternal notch and a rigid metal tube is inserted through the incision, down into the mediastinum, anterior to the trachea. Forceps come out of the lower end of the tube, and that's what's used to get the sample of the lymph node. With these forceps entire lymph nodes can be removed or they can biopsied. This enables acquisition of large tissue samples and that's very helpful for establishing a benign diagnosis. In other words, for excluding malignancy. Think about it. If a patient has a fine needle aspiration biopsy, in other words a cytologic biopsy, and we don't get that cancer, we don't know if the lesion is non-cancerous or whether we have simply missed the malignancy due to sampling error. So again, acquisition of large tissue samples can be very helpful in this setting. What stations can be accessed with mediastinoscopy? Well, any lymph nodes that are near the trachea, lymph nodes that hug the trachea. For example, Stations 2 and 4, the upper and lower paratracheal nodes, as well as station 7, the subcarinal region. So here, we see these lymph nodes that hug the anterior lateral aspects of the trachea and these lymph nodes here. As well as this one in front of the carina, all of these lymph nodes would be potentially accessible for sampling with mediastinoscopy. Let's move on now to our second surgical technique and that is the Chamberlain procedure. A Chamberlain procedure is also known as a left median sternotomy or an anterior mediastinotomy. And this is how it's done. An incision is made over here, at the left, 2nd to 3rd intercostal space, just to the left of the sternum. And the biopsy is either done under direct vision, or under a scope, very similar to the scope used for mediastinotomy and then the samples are obtained with forceps. As with mediastinoscopy, a Chamberlain procedure enables the acquisition of large tissue samples, and again that's very helpful when we want to exclude malignancy. What stations are accessible with the Chamberlain procedure? The only stations that a Chamberlain can reach are Stations 5 and 6, as we see in this diagram. Station 5, the AP window and station 6, the anterior para-aortic region. In this patient, we see a station 5 lymph node. Here we see a station 6 lymph node and these lymph nodes would be accessible via a Chamberlain procedure. Let's now turn to our third surgical technique, and that is a VATS procedure, which stand for Video Assisted Thoracoscopic Surgery. A VATS is done with three ports in the chest wall, one for the fiber-optic scope, and two other ports for various forceps and instruments. And this is what it might look like on the inside. Here is our fiber-optic scope and here are forceps that are grabbing this lymph node. A VATS procedure requires general anesthesia and the patient must be able to tolerate single lung ventilation. The procedure can be done either as an inpatient or as an outpatient and that may vary depending on what sort of practice you're in. Generally, a VATS procedure has low morbidity only about 5% is what's reported in the literature. When morbidity does occur, that's usually due to a prolonged air leak, or a bloody plural effusion. As with the other surgical procedures, mediastinoscopy and chamberlain, a VATS procedure enables acquisition of large tissue samples. What stations can we reach with a VATS? Well, just like a Chamberlain, we can get to Stations 5 and 6. However, a Chamberlain procedure can only get to Stations 5 and 6 whereas a VATS can reach much other areas. And partly because of that it is largely supplanting the Chamberlain procedure in many surgical practices. So, with the VATS, we can get to these lymph nodes in Stations 5 and 6. But we can also get to inferior 7,8 and 9, as well as sometimes the paratracheal lymph nodes and the hilar lymph nodes. So the thing to remember is that the thoracoscope is inserted into the plural space and any lesions that touch or nearly touch the plural surface can potentially be sampled with this type of technique. So not only lymph nodes but also lung and pleural lesions can sometimes be sampled at the same sitting using a VATS procedure. Here's an example of a patient who had a central left upper lode lung cancer and an enlarged station 6 lymph node. The VATS scan showed both the lesion in the lung and the lymph node were FDG-avid and both of these lesions would be potentially accessible for biopsy using a VATS. Let's look at an example of a patient we saw at our weekly tumor board meeting. This was a 58 year old man who presented with a paraneoplastic syndrome. We obtained a CT scan to look for a primary cancer that might be the cause of his syndrome. The only thing we saw in his CT Were these enlarged lymph nodes in the mediastinum. A PET scan was obtained and only those lymph nodes were abnormal on the scan. There were no other abnormalities. So we figured we really needed to biopsy these lymph nodes and the first thing we asked was what station were these lymph nodes in. And we would label these station 5 this is the aorta pulmonary window. Okay, so here's our next question, how would we biopsy a station 5 lymphnode? Would we choose mediastinoscopy, or a chamberlain procedure, or a VATS procedure? So go ahead and pick your best choice here and actually, there are two good choices here. So you could get to a station 5 lymph node with either a Chamberlain procedure or with video assisted thoracoscopic surgery. Mediastinoscopy would not work because these lymph nodes do not hug the trachea. So this patient actually underwent a VATS procedure, and pathology came back large cell lung cancer. And that person limply was accounting for his paraneoplastic syndrome. Well, that brings us back to our pre-lecture question, which is now a post lecture question. So if you remember, we had this patient with a new right pair tracheal lymph node. He'd had previous lung cancer, we were concerned he had recurrent lung cancer and here is the question. What would be the best way to sample this station 4R lymph node. So go ahead and choose between mediastinoscopy or chamberlain or a VATS procedure. And the best answer here would be mediastinoscopy, you could not get to a station 4R lymph node with a chamberlain or with a VATS. He actually did undergo mediastinoscopy and pathology came back non necrotic granulomatous inflammation In other words, a benign diagnosis. We felt comfortable with this diagnosis because the surgical procedure gave us a large tissue sample, so we weren't too concerned about sampling error and missing a malignancy. And in fact, he has done quite well since this time, so this was actually a benign lymph node. Okay, so let's get to our take home points. First of all, surgical techniques yield large tissue samples and that can be very helpful in making a benign diagnosis. For mediastinoscopy, we can access lymph nodes that hug the trachea or the carina. A Chamberlain procedure can reach only stations five and six whereas a VATS procedure has very wide coverage, it can reach lymph nodes and other types of lesions that touch the pleural surface. Okay, well I thank you for your attention in this part 1 for the next lecture we'll be talking about medical techniques, including transbronchial needle aspiration biopsy, also known as a Wang procedure, endobronchial ultrasound and endoscopic ultrasynography. And i look forward to talking with you next time.
