Image guidance, ablative therapies advance renal surgery

February 2, 2013

Advances in intraoperative imaging and minimally invasive surgery have significantly improved the surgical approach to small renal lesions.

Advances in intraoperative imaging and minimally invasive surgery have significantly improved the surgical approach to small renal lesions. In this interview, Jaime Landman, MD, discusses new imaging techniques and image-guided surgery for renal and other genitourinary tumors, cost versus benefit of these procedures, and the role of the radiologist. Dr. Landman is chairman and professor of urology and professor of radiology at the University of California, Irvine, He was interviewed by Urology Times Editorial Consultant Stephen Y. Nakada, MD, professor and chairman of urology at the University of Wisconsin, Madison.

Q:What do you see as the primary advancements in intraoperative ultrasound and other forms of intraoperative imaging?

A:When we think of advances, we often think of major leaps forward. I would rather approach this from the perspective of incremental improvements in the technology that exists. In the short time that I’ve seen ultrasound used in the OR, it’s gone from a rather crude, minimally useful tool to something that I find utterly indispensable in my own practice. As ultrasound technologies are not disposable pieces of equipment, they can be utilized regularly and in a cost-effective manner despite a relatively high initial purchase price. Incremental advances in intraoperative ultrasound include vastly improved quality of imaging, which allows for very precise understanding of anatomy; improved evaluation of vascularity via duplex technologies; and even intuitive targeting mechanisms, which allow urologists to deploy needles or probes with great precision.

Q:What should the practicing urologist embrace and consider when it comes to intraoperative imaging?

A:With contemporary technology, ultrasound is clearly the way to go. Thanks to our surgical colleagues who have wholeheartedly embraced intraoperative ultrasound, it is something that is routinely available in almost every operating theater and is easily learned. Having not had the training to use these technologies in my residency or fellowship, I would argue that there is some self teaching that needs to be addressed. Very often, collaborating with radiologists who are much more comfortable with ultrasound will help. The real key is just routine application of ultrasound during all of your laparoscopic cases. After a bit of time, and with some experience, I am confident that most urologic surgeons would find intraoperative ultrasound an indispensable tool.

During challenging cases, I have found intraoperative ultrasound critical in helping to identify anatomy. This has kept me out of trouble more than a few times. With regard to safety, I am confident that ultrasound has been under­utilized. It is a magnificent way to establish where major vasculature is located and provides an excellent roadmap for dissection, especially in those challenging cases where the anatomy is distorted or where a reactive process doesn’t let you immediately understand where you are.

Perhaps the most appealing contemporary application of intraoperative ultrasound is blood flow assessment. During renal surgery, we are increasingly interested in ­characterizing ische­mia. The early identifying vessels can help avoid complications. For years, my team and I have used intraoperative blood flow assessment to ensure optimal clamping ischemia prior to renal ­parenchymal transection. We have avoided the unpleasant surprise associated with a poorly clamped kidney during partial nephrectomy. More recently, we’ve seen the introduction of smaller inexpensive Doppler probes that can measure renal blood flow millimeter for ­millimeter with great precision, and this technology has facilitated renal segmental artery clamping for partial nephrectomy procedures. While there have been recent reports of using intravenous agents and advanced imaging to facilitate identification of segmental renal ischemia, ultrasound technologies can do this much more effectively and with less expense.

Q:Let’s shift gears a bit and talk about image-guided therapies. What do you think some of the advances are in terms of the imaging aspect of image-guided therapy?

A:Advances come from two arenas: the imaging side and the ablation side. For example, when it comes to percutaneous ablation procedures, the efficiency of contemporary CT scanners has allowed for close to real-time deployment of ablation needles. Certainly, this will improve efficacy and reduce complications. High-quality CT scanning technology makes it much easier for urologists, hopefully working in conjunction with interventional radiologists, to target tumors very precisely.

Looking at the very near-term future, ablation under MRI guidance is right around the corner. At the University of California, Irvine, we are launching an MRI-guided cryoablation program. This is particularly exciting in an era where we and our patients are starting to worry more about ionizing radiation. MRI-guided cryoablation, by eliminating ionizing radiation, is very appealing to patients. Additionally, as there is no limitation as to the amount of imaging in MRI-based image-guided therapies, we can observe the ablation process in real time.

What is particularly exciting about the application of MRI for image-guided therapies is that MR thermography will allow us to not only follow the image of tissues being ablated, but actually will facilitate precise real-time temperature monitoring to optimize the safety and efficacy of ablation.

Q:Do you think the costs merit the benefits of these treatments?

A:I actually believe that today the costs probably already justify the application of image-guided therapies. We need to look at the cost globally, which is rarely done. By considering the diminished complication rates, the short hospital stay, and all the other benefits of the very minimally invasive nature of these procedures, we would appreciate how cost effective ablation has already become. Looking at the larger picture, we also should consider that image-guided therapies get people back to work and to normal activity and productivity more quickly. Looking toward the future, of course, these technologies will only get better and become even more cost effective.

Q:In the setting of rising health care costs, should hospitals embrace new intraoperative and imaging technology or be more reactive toward it?

A:That’s a tough question. I do believe that image-guided therapies are cost effective. The limited analyses that have been done to date demonstrate that the treatments are very reasonable. As we look toward the future with new technologies, initially they will be expensive and this is where there is some cause for concern. As with all new technologies and products, as they become more common and are used more routinely, they will become more cost effective. That, of course, is the price of progress.

Q:What is the role of the radiologist in using these new technologies?

A:The role of the radiologist continues to evolve and is currently very difficult to define. In my mind, it’s clear that a collaborative relationship during image-guided therapy procedures is absolutely mandatory. Certainly, collaboration is not necessarily easy to achieve. However, the harmonious application of two skill sets, that of the urologist and the interventional radiologist, will likely result in optimal outcomes for patients. Having personally worked with two different interventional radiologists very collaboratively at two different institutions, I am confident that our outcomes are far superior as a team than they would be with either of us doing these procedures individually.

Q:How would you advise young urologists about advances in intraoperative imaging and image-guided therapies?

A:I think you have to go back to the basics. A young urologist needs to understand the biology and epidemiology of the disease that they are treating to make smart decisions about which patients are suitable for these treatments. By understanding the disease, be it a small renal cortical neoplasm, prostate cancer, or any other urologic pathology you want to treat with an image-guided therapy, you will probably make the best decisions about who should have the treatment. At that point, like any other technical exercise, good technical training, having a good handle on how to do the procedure, knowing the different options for doing the procedure, understanding the procedure’s complications, and how to manage complications are very important.

Q:For a young urologist who is just starting practice, when selecting their hospital, how aggressive should they be in terms of mandating the latest in intraoperative imaging and image-guided treatment?

A:I’ll speak to that with regard to my personal experience, which is almost entirely in the small renal cortical neoplasm arena. For me, understanding the biology and epidemiology of that particular entity has forced me to depend heavily on image-guided therapies. I would also argue that it’s forced me to depend heavily on active surveillance as a key strategy for taking good care of my patients. With that being said, I would fight vigorously to have those technologies incorporated into my clinical armamentarium. To treat small renal cortical neoplasms comprehensively in the year 2013, a urologist should incorporate image-guided therapies as a treatment strategy.

Q:What do you think are the key technologies that the young urologist should be requesting in 2013?

A:There are currently two modalities for renal ablation that are well documented as clinically successful: radiofrequency ablation and cryoablation. There are many strong opinions as to which of these technologies to apply, but looking at the situation objectively, I would argue that whichever technology you are comfortable with and know how to use well will be the technology that you use successfully for your patients.

Q:There were several abstracts presented at the 2012 AUA annual meeting on microwave therapy. Do you have a position on that?

A:I’m entirely intrigued by microwave therapy, and I think it may evolve into the third clinically acceptable ablative technology for renal applications. I have worked with microwave therapy in the laboratory and was very impressed by a number of different characteristics, including the degree of hemostasis and the size of the ablation lesions.

Having spoken to some very close colleagues who have also evaluated microwave ablation in the lab and clinically, it seems there are many details of the technology that have not been worked out. At the University of Miami, Dr. Ray Leveillee and his research team have evaluated some technologies and have seen some substantial problems with clinical applications. Having discussed this candidly with Dr. Leveillee, he believes that it’s a function of which technology is used. I’m not offering microwave ablation to my patients at present, but it’s something that our team will continue to look at in the near-term future for clinical application.

Q:To wrap up, what do you think the future directions are in intraoperative imaging, renal surgery, and image-guided treatment?

A:Regarding image-guided therapy, I think we are going to see a lot more of it used clinically. I do not think that the future will be about ablation as destroying tissue is rather easy. The future will be more about advanced targeting modalities that will help us be much more precise about how we destroy tissue. High-fidelity imaging and other information sources such as temperature monitoring, which can be achieved with MR thermography, may be extremely useful for precise targeting, and will likely revolutionize the way we target and destroy tissue.

With regard to extirpation, the application of ultrasound and the newer iterations of ultrasound technologies have already improved the ability to do traditional extirpative therapies in a very positive way.