Oncology Convention

6 - 7 July 2022
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31 Mar 2021

Write Up: Image Guidance for Bronchoscopy and Lung Surgery

Adam Randall

On the 12th of March, we were pleased to host Dr. Kelvin Lau’s talk “Image Guidance for Bronchoscopy” as part of Oncology Convention Virtual. The webinar, which was sponsored by Philips, contained Kelvin’s perspectives on his use of a hybrid theatre and how it could revolutionise the removal of nodules from the lungs. 

Kelvin is a distinguished thoracic surgeon and in 2015, his team was the first in Europe to successfully use the latest version of navigational bronchoscopy. In 2018 he was the first person in the world to perform a microwave bronchial ablation on a lung tumor. These were just a few of his many accomplishments from his storied career and he used this talk as an opportunity to share his expertise with other surgeons. 

It’s becoming more and more challenging for surgeons to remove lung lesions because as medical techniques advance, preventative cancer treatments start much sooner. Today the lung lesions which are detected tend to be very tiny, very deep in the lung and often not even solid. This presents a challenge to surgeons. 

The percutaneous method 

Traditionally, the solution to this problem was to biopsy the lesions using a CT scanner. The patient would have a needle stuck through their chest to the point of the lesion. This is called the percutaneous method. While it is very straightforward, it comes with risks: 

  • This is an unanatomical method and the breaching of the chest and lung to reach the lesion is a cause of trauma for the patient. 

  • 40-50% of patients who undergo this treatment will suffer from a collapsed lung. 

Other fields of medicine have moved away from the percutaneous method and towards endoscopy, which is good for both biopsies and therapeutic procedures and Kelvin firmly believes that this is the future for treating lung cancers too. 

Navigational bronchoscopy 

With so many pathways within the lungs, it is understandable that finding the lesion within them could be an intimidating task. Additionally, with so many narrow passages within the lungs, another concern is that the bronchoscope will get stuck and be unable to proceed deeper into the lung to reach the lesion. 

These problems can be avoided through the following method: 

  • Start with a CT scan of the patient’s lungs. 

  • Highlight the location of the tumor on a computer. 

  • Press the “find airway” function to calculate a path to and from the lesion. 

  • The computer will create a simulation to allow you to do a practice trial run. 

  • On the day of the procedure, the CT needs to be mapped onto the patient. 

  • The computer than matches the CT to the trajectory of your movement. 

  • You’ll then be able to see both, side by side, as you make your way through the lungs. 

  • When and if the bronchoscope gets stuck in any passage, a channel with a sensor comes out of the end of the bronchoscope and navigates its way through the tight bronchus to the tumor. 

  • Additionally, if you get stuck and there’s no source of light when controlling the channel with the sensor, you can depend entirely on the computer imaging to find your path, though this can be challenging. 

This process avoids a great deal of pain, discomfort and later complications for patients, while providing the added benefit of making it possible to biopsy multiple nodules in one session. It is hoped that, in future, navigational bronchoscopy will completely replace percutaneous biopsies. 

Overcoming the weaknesses of navigational bronchoscopy 

The one weakness of navigational bronchoscopy is the reliance on a CT overlay. For this procedure, absolute certainty is required. To get around this problem, Kelvin uses cone beam CT which gives him real-time image guidance. It creates a 3D rendition so that even if you struggle to interpret the imaging, you can see the biopsy force reaching the nodule. The technology provides absolute certainty, helping you to avoid the needless distress to the patient and eliminating the risk of having to repeat the procedure. 

Cone beam CT uses fluoroscopy to turn a 2D image into a multiplanar CT scan. Once this has been done, you are left with a 3D rendition which gives you a clear idea of how to navigate through the lungs. The nodule can then be overlaid onto the fluoroscopy so that even though you can’t see it on the normal x-ray, you know where it is because it can be highlighted and superimposed onto the CT. This process is called augmented fluoroscopy. This is particularly useful when dealing with nodules which are hard to locate. This process provides a method for dealing with cancers which doesn’t involve exposing the patient to radiation. 

Localising pulmonary nodules for resection 

Sometimes, lesions cannot be seen on the surface of the lung. Historically, surgeons would approach this challenge using something called the hook wire method: 

  • A radiologist would be asked to breach the lesion with a wire. 

  • The patient would then be lifted with the wire sticking out of their chest. 

  • The surgeon can then see where they would need to make an incision. 

  • Unfortunately, this process would often fail due to wire breakages. 

Kelvin believes that it is much better to solve this problem with an endoscopic method, rather than a percutaneous one as it is more effective and avoids bodily breaches. The endoscopic approach consists of the following steps: 

  • Start with a navigational bronchoscopy to find the lesion. 

  • Insert a fiducial (a.k.a. gold seed marker) which will help turn an invisible, impalpable lesion into one which is visible with a surrogate marker. 

  • Get the patient set up in the hybrid theatre immediately after the bronchoscopy so that the surgeon can see where to go on the x-ray, find it and then clamp it. 

  • Put a staple below it, ready for it to be sent off to the lab. 

The process above can also be extended to image-guided robotic surgery. Sometimes, a segmentectomy must be performed due to the small size of the lesion. What this involves is removing a small segment of the lobe, rather than the whole lobe itself. 

The robot provides what is essentially a microscope inside the chest, which means that you can conduct a very detailed and accurate segmental dissection. Unfortunately, there have been times when surgeons have performed this procedure, only to find that they have not actually removed the nodule or that it was crushed by the staple line. Here’s an example of how Kelvin was able to avoid this problem: 

  • As always, he started with a navigational bronchoscopy, locating the nodules and performing a biopsy. 

  • He identified whether or not they were cancerous and in need of removal. 

  • He inserted a fiducial. 

  • Due to the size, a lateral segmentectomy had to be performed. 

  • The robot gave Kelvin a view of the nodule. He positions one of his instruments on the intersegmental plane between the apical segment of the lower lobe and the basilar segment and the other instrument between the lateral segment and the anterior segment. 

  • He moved them around so that he could get an inter-operative view and triangulate the location of the nodule. 

Once he had completed this process, he could proceed without any element doubt. He had diagnostic certainty and could see exactly where the nodule where he was. This allowed him to complete the procedure with confidence.  

Ablating cancers which cannot be resected 

In some instances, it is not possible to resect cancerous tumors. This usually happens in the case of patients who have been life-long smokers and, as a result, have very poor lung function and will not be able to tolerate the stress of lung surgery. There are three main solutions available in these instances: 

  • Percutaneous ablation: as described above, though this method can be successful, it still presents significant risk to the patient. 

  • Radiotherapy: Though this has the distinctive benefit of being non-invasive, it also requires the patient to make numerous visits to the hospital and has all of the risks associated with exposure to high levels of radiation. 

  • Endoscopic: Once again, Kelvin believes this to be the superior procedure in this situation. 

When using the endoscopic route to solve this problem, Kelvin would start the process using navigational bronchoscopy. Once the nodule has been located, he would then simply burn it off. This can be completed in just ten minutes. 

In an incident where a patient who had previously had a lower lobectomy and now had a nodule right in the middle of a lobe, Kelvin performed a navigational bronchoscopy and inserted an ablation catheter. Kelvin’s computer system was able to recognise the catheter’s characteristics immediately as the data was already stored within. The computer was then able to tell him what the ablation zone for the module was and the system found the borders of the lesion in mere seconds. To ensure that he had good ablation adequacy, he had the computer add a one-centimetre margin. He was able to view a 3D rendition of everything for added clarity. 

Beyond the lungs 

Though Kelvin's primary focus was on the benefits of navigational bronchoscopy for the use of removing nodules from the lungs, he wanted to bring the webinar to a close by talking a little bit about applications in other parts of the body, particularly those that present similar challenges to surgeons trying to locate lesions.  Here are a few examples: 

The chest wall 

Kelvin was once able to remove a metastasis from a patient’s chest. He performed a CT scan in order to locate the rib on which the metastasis was located and placed a pin in the patient’s chest at either side of the metastasis, including a small margin. It could then be removed with just a small incision.  

One patient with breast cancer had a hot and sclerotic segment of marrow, but scans had no stigmata to help them identify which rib it was on. Using augmented fluoroscopy, he localised the lesion then overlaid it on the fluoroscope, which allowed him to identify the exact rib. He then inserted a needle to mark the location. This process is minimally invasive and can be done with certainty with just one small perfectly placed incision. Ideal for anything just under the ribcage. 

Lower chest 

Kelvin once had a case where an abnormal mass was located between a patient’s liver, diaphragm and chest wall. He segmented out the lesion and the computer helped him to identify the exact location upon which he should insert the needle. Once he had made a small incision, this otherwise difficult to reach mass could be removed with ease. The patient was even able to return home the very same day. 

Kelvin admits that none of this would have been possible without the Hybrid Theatre. In his own words:

This has opened my eyes, literally, to a lot of things, that in the past would have required using visible light and looking at the surface of the organs, limiting me.... It gives you the ability to expand your senses so that you can see things that you can’t normally see. 

 

 

He closed the webinar with a live Q & A session with the audience. If you would like to watch the full webinar, it is available via our on demand service until the 12th of April. Watch it to get lots of extra details from Kelvin and to see photographs and imaging from cases Kelvin has worked on previously. Watch it now! 

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