SURGERY THROUGH THE KEYHOLE The cost of access of minimally invasive surgery is that surgeons can only see the surface of internal organs and "feel" the texture indirectly through long instruments, says SAGES President Gerald Fried, MD.

Most elective surgery today is carried out using laparoscopic techniques. Nobody can question the benefits of minimally invasive surgery for the patient. There's less pain, nearly invisible scars, improved surgical precision and a markedly accelerated recovery. But what about the surgeon? For all of laparoscopy's benefits, aptly named keyhole surgery poses some very real and often overlooked visualization challenges to the surgeon. Yes, working through puncture-size incisions limits what we can see and feel.

We've done a great job of minimizing the cost of surgical access for the patient, but at some expense. We're left flying somewhat blind, performing surgery without being able to directly see beyond the surface of internal organs and feeling tissues with the tips of long instruments that we've placed through ports in the abdominal wall. We must rely instead on a flat image projected on a monitor generated by the tip of our scope.

Depth perception can be a problem during MIS. We're limited to visualizing internal structures through a 2-dimensional optical system that diminishes depth perception. We must acquire new cues to know where we are in 3-dimensional space. Decreased tactile sensation is another challenge. We're using long instruments interposed between the surgeon's hands and the target to access the organs or tissues being operated on. We also have to contend with limited range of motion that results from passing instruments through trocars and the "Fulcrum Effect." To make the laparoscope tip go in one direction, the surgeon's hands must move the handle of the instrument in the mirror-image direction. Last but not least, nothing can impair the view like a lens coated with blood or mucus.

Technology to the rescue
Thanks to great advances in technology, laparoscopic surgeons can now overcome most of these obstacles. Here are 6 milestones that have helped advance the quality of the image that we work with.

• High definition. The move from standard definition to high definition has greatly improved the quality of the image that we see. HD gives us a startling amount of information — magnified, bright and shadow-free visualization of internal structures. You see things that you simply weren't seeing in the past.
• Smaller, more light-sensitive scopes. You've probably noticed that as scopes are getting thinner and thinner, the quality of the image is getting better and better. We have improved light sensitivity to thank for this. A benefit of thinner scopes is that we create smaller openings in the abdominal wall to see inside, further reducing the injury of access.
• Flexible tips. Original laparoscopes had fixed angles of view. The scopes' fixed view made it difficult to see the top or bottom of tissue. Thanks to our industry partners that have developed endoscopes with flexible tips at the end, we're able to look at our target from different angles. We can direct the tip up, down, left and right with the press of a tiny lever. A tremendously helpful advance for some surgical procedures, yes, but one that added a bit of a learning curve and required additional training.
• Prisms. A recent innovation is a rigid scope with a prism at the end of it that lets you click your way to a different angle of view. Prisms offer a great way to look at things from different perspectives. You can change the angle of the lens with a dial. You can get either a straight-on view or a 30-degree view with a single scope, for example.
• Binocular optics. The development of binocular telescopes that deliver 3-dimensional, high-resolution images marks the next evolution in optics. These scopes offer really good depth perception. These binocular optical systems come with 2 lenses, each providing an image to each eye. Some surgeons have a hard time getting oriented in 3D space with a monocular optical system, while others make that leap seamlessly and find it extremely enabling. It's too early to know whether this is a game-changer, but it has the potential to be so.
• Ultrasound. With laparoscopy, you only get visual information about the surface of internal structures. But that tumor you see from the surface might be the tip of the iceberg. It would be nice to get a view of what's underneath the surface of our target tissue. An experimental concept worth tracking is a scope that would provide traditional laparoscopic views with real-time ultrasound to see beneath the surface. It would fuse volumetric (3D) with surface views. We could evaluate a tissue's density and its characteristics in conjunction with the surface view provided by the scopes.

None of these developments require larger incisions or increase the risks of surgery, yet they all enhance the surgeon's capabilities to see more and to see better.