Over the past 2 decades, the evolution of surgical video has largely centered on increasing the quality of images captured in minimally invasive procedures. "Single chip, triple chip, HD, 3D, 4K: We've spent a lot of time and energy on getting a better picture, on replicating real life," says Paresh Shah, MD, a professor of surgery and chief of the general surgery division at NYU Langone Medical Center in New York, N.Y.

Beyond higher resolution, though, beyond wider screens and depth perception, another field of imaging technology promises the ability to show more than real life, with views of anatomy that the human eye cannot naturally see. Image enhancement technologies, available as on-demand camera and control unit settings in several manufacturers' laparoscopic, endoscopic and arthroscopic video systems, deliver a heightened level of surgical visualization.

Illumination-driven options such as the fluorescence imaging of injected dye or light filtered down to selected wavelengths enable contrast-enhanced views of the mucosal surface and the vascular networks microns or millimeters beneath it. Other modes apply digital processing to captured video in order to make anatomical structures in the dark parts of an image more visible, intensify color to better highlight differences in tissue, or — co-opting military advances that have helped drone aircraft see through cloud cover — give users a clearer sight through surgical smoke and laparoscopic fog.

"We're going from trying to make the visuals better reflect reality, to developing tools that allow us to see past the visible spectrum," says Dr. Shah.

Adding to the advantage, these imaging boosters work in real time, providing physicians with an up-to-the-moment view of critical details that can ensure patient safety and even improve surgical outcomes.

SAFE ENTRY Lap chole cases demand their own culture of safety, says SAGES.

PRACTICE PRECAUTIONS
Making Lap Chole Safer

The use of image enhancement technology is a key component of the Society of American Gastrointestinal and Endoscopic Surgeons' Safe Cholecystectomy Program (osmag.net/h4uSSH), a set of guidelines that aim to minimize bile duct injuries during the laparoscopic procedure. Other steps include using the Critical View of Safety method to identify anatomy, taking an intra-operative time out before cutting ductal structures, understanding the possibility of anatomical aberrations, recognizing dangerous dissections and changing course if necessary, and calling in another surgeon for help.

— David Bernard

Karl Storz Endoscopy-America
Clara and Chroma

TEAM EFFORT Working together, Clara and Chroma make dark anatomy easier to see and intensify its color values during a Nissen fundoplication.

Bringing Brightness to the Dark and Contrast to Color
A pair of image-enhancing technologies built into the Karl Storz Image1 S endoscopic platform boosts the quality of video visualization in general surgery, orthopedic, gynecological and urological cases. Driven by proprietary algorithms, Clara and Chroma overcome obstacles to illumination in minimally invasive surgical sites.

Clara automatically identifies and evenly brightens the dark areas of an image that result from small spaces and deep cavities. It does this in real time, without a lag, and without adjusting the brightness of the light source, which — in increasing the reflection from surfaces in the foreground — creates a distracting glare.

Chroma, often used in conjunction with Clara, intensifies an image's color contrast levels. It enhances the reds while retaining the natural perception of the anatomy, in order to emphasize and differentiate key tissue areas, precisely define blood vessels and other critical landmarks, and create a greater sense of depth perception.

— David Bernard

A step up for safety
Traditionally, "doctors operate based on reflected light. That's how they can see," says Wayne Poll, MD, a urologist by training who now runs a minimally invasive surgical device manufacturer in Columbus, Ohio. "They cut a little bit into the plane of what's reflecting the light. The entire teaching of surgery is how to identify and isolate tissue while operating."

Being as sure as possible that you know what you're cutting into is the key to minimizing damage, says Dr. Poll. Keep in mind, however, that each patient's anatomy is, to a certain extent, subject to variability and ambiguity. "The entire experience of surgery is how to get out of trouble," he adds. "The ability to see things has great value."

The ability to see things, and to avoid accidentally nicking or slicing them, is image enhancement technology's contribution to reducing surgical risk and the rate of post-op complications in minimally invasive surgery. "It's a cadence to minimize damage to tissue you can't see," says Dr. Poll. The real-time road map it provides of blood vessels, ureters, the biliary tree, nerve bundles and other critical anatomy, and the electronic adjustments it provides to brighten and clear that view, offer a major safety benefit over even the soundest techniques.

Consider, for example, laparoscopic cholecystectomy's techniques. The rate of common bile duct injuries increased to 0.5% nationally following the development and introduction of the lap chole procedure, according to a survey reported in a 2001 issue of the Annals of Surgery (osmag.net/PhyAK6). Santiago Horgan, MD, chief of the minimally invasive surgery division at the University of California San Diego School of Medicine and director of its Center for the Future of Surgery, has described this complication as "the Achilles heel of laparoscopic surgery."

"These injuries occur when you don't expect them," he remarked in a demonstration of image enhancement technology at the Society of American Gastrointestinal and Endoscopic Surgeons' annual meeting in March. "Common bile duct injuries never happen when it's difficult. They happen when you think it's easy."

The solution, says Dr. Horgan, is at surgeons' fingertips. "Click a button, and that [white light] image becomes that [fluorescent-lit] image, and suddenly you have a 100% guarantee that you are not clipping the common bile duct," he says. "Now we know exactly where the anatomy is." Two minutes with intraoperative contrast imaging, he adds, gives you what X-rays take 11 minutes to do. "This could change how surgery happens in the OR," he says.

Novadaq Technologies
PINPOINT Endoscopic Fluorescence Imaging System

1. The SPY Fluorescence mode highlights a colon resection.
2. A colon resection seen through the PINPOINT Fluorescence mode.
3. The SPY CSF (color-segmented fluorescence) mode during laparoscopic cholecystectomy.

The SPY Who Improved Minimally Invasive Surgical Visualization
Novadaq's PINPOINT laparoscopic technology combines the company's SPY imaging capabilities with conventional high-definition white-light visualization in a single scope platform. The black-and-white SPY Fluorescence mode, green-contrast PINPOINT Fluorescence mode and SPY CSF (Color-Segmented Fluorescence) mode offer different variations on visible light. They enable surgeons to visualize blood flow in vessels, tissue perfusion and anatomical structures to serve a range of minimally invasive procedures in real time, without interrupting surgery, and with no radiation exposure.

What's more, they do it all at the same time. The PINPOINT imaging system provides simultaneous HD white-light views and on-demand HD fluorescence views as well. A light source designed to continuously illuminate the site with different wavelengths of the spectrum and a laparoscopic camera developed with multiple sensors that separately detect these types of light means surgeons don't have to change their operating plans or toggle between modalities in order to obtain the most effective image.

— David Bernard

A diagnostic advantage
In addition to its safety benefits, image enhancement technology elevates minimally invasive surgeons' diagnostic powers and may even improve their likelihood of achieving successful outcomes. During upper and lower GI tract screenings, for instance, specially filtered illumination or digital image processing can help to highlight subtle changes in tissue and vascular patterns that may indicate otherwise undetected pre-cancerous polyps or other mucosal malignancies.

"Flat but clearly atypical cells are not easily distinguishable, but now they stand out," says Dr. Shah, adding that the availability of image enhancement applications has changed the effectiveness of endoscopy. "The simple fact is, we missed a lot. As good as we were, we weren't as good as we are now. We're better, as the technology allows us to be better."

Surgical results might be better as well. Fluorescence imaging doesn't just help you see where not to cut, it also suggests the sites that will heal the best. Once injected, indocyanine green — the contrast dye that fluorescent light excites into visibility — binds to plasma proteins for a few minutes before being removed by the liver. While it's actively glowing green, it demonstrates where the blood flows and, consequently, the quality of its tissue perfusion.

This is extremely beneficial information when performing colorectal, esophageal and bariatric resections, says David Renton, MD, FACS, MPH, an assistant professor of surgery at the Ohio State University's Center for Minimally Invasive Surgery in Columbus, Ohio.

"You don't know how good the blood supply is to the ends," he says. "But if you switch on the filter, the fluorescence will tell you how well you'll be able to create an anastomosis. If it glows, it has good blood flow. If it doesn't glow, there is no blood supply. You can avoid any kind of leaks."

Improved visualization could even improve your physicians' efficiency, says Alexander Rosemurgy, MD, director of the Southeastern Center for Digestive Disorders at Florida Hospital Tampa. "Before, the best you could do might have been less accurate. But this changes how long it takes you to do the incision, and ultimately the length of surgery."

Olympus America
Narrow Band Imaging

BEFORE AND AFTER In comparison to white-light visualization (left), Narrow Band Imaging (right) more clearly highlights the pathology of bladder cancer.

Limiting the Light Makes Vasculature More Visible
Narrow Band Imaging, a proprietary technology incorporated into Olympus's flexible endoscopes, provides gastroenterologists and urologists with a high-contrast view of mucosal surfaces, their blood vessels and even the boundaries of lesions lurking there, without the use of contrast agents. How? Its insights are powered by selective illumination.

In a laparoscopic view of anatomy, white light — which is made up of all the colors of the spectrum — reflects off the subject, enabling its visualization. Specific wavelengths of light, however, are capable of penetrating the surface. And hemoglobin absorbs blue and green wavelengths. So when Olympus's scopes are activated to filter their light sources from white light down to narrow bands of blue and green, the resulting illumination emphasizes the blood vessels over the mucosa's non-vascular feature. Capillary networks on the surface appear brown, while deeper veins appear cyan.

While Narrow Band Imaging uses direct illumination to deliver contrast imaging, other scope manufacturers' proprietary electronic chromoendoscopy systems employ software-driven digital image processing to enhance their views. Fujifilm's FICE (Flexible Spectral Imaging Color Enhancement), Pentax's i-SCAN and EndoChoice's recently announced Lumos Adaptive Matrix Imaging (awaiting FDA approval for the company's Fuse scope) analyze white light to selectively highlight specific wavelengths of reflected light and anatomical features.

— David Bernard

Nice or necessary?
Image enhancement technology clearly offers advantages to surgeons performing minimally invasive procedures. But are those advantages essential to the safety of surgery and the success of its outcomes? After all, laparoscopic techniques flourished before the development of these real-time visualization improvements.

"It is nice, yes, but you can do procedures without it," says Sharona Ross, MD, director of minimally invasive surgery and surgical endoscopy at the Southeastern Center for Digestive Disorders at Florida Hospital Tampa. She admits that it makes training easier, as well as cases that involve advanced illness or inflammation. In general, though, "it's not that hard to cut. If you follow standard steps and techniques, you're not likely to cause injury."

"We're far from it being standard. We're not there yet, but the scope of applications is growing rapidly," says Dr. Shah. "Frankly, they're still relatively young technologies, and the clinical data is lagging behind the technical data. Just because the imaging looks different and looks better, does it bring value? These are meaningful metrics we're trying to move."

For example, while surgeons resecting the colon believe that a better blood supply — and as a result, contrast imaging of the colon — leads to a lower risk of leaks, there isn't enough rigorous data to conclusively prove the point, he says.

As with high-definition cameras and displays, image enhancement's clinical benefits might be unverified, but its practical benefits are unquestioned. "The stuff works," says Dr. Shah. "Does its working translate into better outcomes? We don't know yet. Can you work better if you see better? Yes."

Of course, any facility considering adopting image enhancement options will inevitably face the issue of cost, since it's not a plug-and-play software upgrade. "It's a great technology, but you have to buy the entire tower and their scope to use it," says Dr. Ross. "Surgical robotics has it integrated in, and it's very useful there, but you wouldn't buy a whole new platform just to do gall bladders."

As Dr. Poll notes, however, "every have-to-have product in medicine started out as a you-don't-really-need-that, from laparoscopy to lithotripsy to the CAT scan." OSM

Stryker
1588 AIM Platform

AIM IN ACTION Clockwise from top left: the ENV, IRIS, DRE, Desaturation and Clarity modes of Stryker's 1588 AIM Platform.

One Tower, 5 Ways to Enhance Video Images
Stryker's 1588 AIM (Advanced Imaging Modalities) Platform offers 5 visualization modes to upgrade minimally invasive views:

• ENV (Endoscopic Near-Infrared Visualization). Contrast-dye-aided fluorescence imaging that allows surgeons to visually assess blood flow, tissue perfusion and the locations of biliary ducts.
• IRIS (infrared Illumination System). Increasing the visibility of the ureters can help to reduce the risk of damaging them. A lighted stent integrated into the system's light source illuminates the ureters without generating heat.
• Clarity employs image-processing algorithms to eliminate visual "noise," sharpen image details and intensify color contrast when surgical smoke, fog, moisture or debris degrade the view.
• DRE (Dynamic Range Enhancement). When the darkness of posterior compartments in the abdomen, joints or other small cavities impairs visual quality, the DRE mode creates a brighter image.
• Desaturation mode allows surgeons to incrementally adjust an image's color saturation — specifically the saturation of reds — ?to their preference in order to respond intraoperatively and immediately to the need to see through an influx of blood or beyond inflammation.

— David Bernard