IN DEPTH 3D visualization can boost laparoscopic abilities for experienced hands as well as those just entering the learning curve.

We live in a three-dimensional world, but our direct experience in minimally invasive procedures has long been limited to two dimensions on a display monitor. The development of 3D imaging in laparoscopic cameras and C-arms, however, has brought needed depth perception to a host of surgical specialties. While the technology may not have caught on as rapidly as high-definition resolution has, there are strong prospects for 3D imaging's widespread adoption. Here are 4 reasons why.

1. Improved surgical skills
Does 3D visualization improve surgical outcomes? That question is still subject to anecdotal evidence and lively debate. Does it give a boost to laparoscopic surgeons' abilities? According to a growing number of clinical studies, the answer is an unqualified yes.

My colleagues and I compared the impact of 2D and 3D visualization on laparoscopic performance for a study published in the November 2012 issue of the Journal of Laparoendoscopic & Advanced Surgical Techniques (tinyurl.com/o4oa94h). We set 33 participants with varying levels of laparoscopic experience to the task of completing 3 drills from the Fundamentals of Laparoscopic Surgery Skill Set — peg transfer, pattern cutting and suturing/knot-tying — in both conventional 2D laparoscopic view and with 3D image guidance.

The participants were randomized as to which visual modality they used first. We measured the amount of time it took them to complete the exercises and the number of attempts required for them to achieve proficiency. We also surveyed them with a questionnaire afterward.

In each of the exercises, the participants averaged greater speeds to completion with 3D visualization, by a wide margin. Regardless of their level of laparoscopic expertise, they made fewer errors in 3D. Fewer participants required multiple attempts to reach proficiency using 3D.

We found no differences in participants' reports of eye strain, headaches or other physiological side effects after using each visual modality. Subjectively speaking, nearly 88% of the participants preferred the 3D view. It stands to reason that a visualization technology that improves skill and that physicians are comfortable with can deliver more efficient and more cost-effective surgeries.

SEE THE WAY The user-friendliness of 3D imaging systems' glasses allow everyone to have a look at the procedure.

2. More information
The value of 3D surgical imaging isn't limited to training or improving techniques. In urological, general, orthopedic, spine and neuro cases, among other specialties, real-time 3D guidance provides more anatomical information and improves the navigation of anatomy.

Consider the radical prostatectomy, a delicate operation. Depth perception in the laparoscopic view can help the surgeon exercise extreme caution around the area's vascular bundles.

Or imagine how a 3D C-arm's ability to construct a pre-operative or intra-operative model of a patient's anatomy from a series of fluoroscopic images can provide immense assistance. Spine surgeons will be able to verify and correct the placement of implant screws during a procedure, for example, and not have to wait for post-op CT scans and potential reoperations. Physicians preparing to undertake a partial nephrectomy would know with greater certainty the proximity of a tumor to arteries and veins, knowledge that is critical to the extrication and reconstruction.

The power that 3D imaging brings to pre-op planning and intraop action can't be overstated. As more laparoscopic specialists become more familiar with the technology's capabilities, the situations in which it is used will expand. No matter how sophisticated the procedure, 3D will always trump a flat image.

LOOKING AHEAD
3D Without Glasses?

VISUAL AIDS New eyewear is comfortable, but surgeons would appreciate operating without it.

Can you envision video display monitors that deliver three-dimensional images without the need for glasses to appreciate the effect? Observers say that science is readying the technology for surgical prime time.

For an article appearing in the January 2013 issue of the journal Neurosurgery (tinyurl.com/o8ld9zv), a team of researchers from the School of Electrical and Computer Engineering at Indiana University-Purdue University at Indianapolis reviewed the strengths and weaknesses of autostereoscopic imaging based on video displayed from a microscope's camera.

Not only do users not have to wear polarized sunglass-style lenses, they write, but multiple users can see the effect simultaneously. Plus, its depth-rendering format can boost the efficiency and accuracy of image-guided surgery's graphic registration and overlay tasks.

While current applications of autostereoscopic imaging are bound to less-than-HD-quality imaging, and the depth perception displayed sometimes appears shallower than it really is, the researchers foresee these shortcomings being resolved in time.

— David Bernard

3. Practicality and cost-effectiveness
3D imaging is a major component of robotic surgery, but robotic surgery is not without its limits. The surgeon who sits at the console enjoys depth perception as he remotely operates the controls, but he does not have the tactile feedback that laparoscopic instruments offer.

The surgeon also relies on his assistant at tableside for endoscopic stapling and other selected tasks. This assistant, it should be noted, does not share the robotic console's 3D view, so his work is guided by a 2D view of the internal site. That's not the only concern. Ceding some tasks to the assistant, who might not have the surgeon's level of experience, may affect the procedure's outcomes.

As we come to realize the limits of robotic systems, whose 3D visualization is yoked to the loss of a certain amount of control for the surgeon, it is possible that more and more image-guided surgeons will migrate to hands-on laparoscopy for their 3D imaging needs, rather than to robotic surgery.

A recognition of the high cost of robotic systems is evidence that 3D laparoscopy is also a very cost-effective alternative to the robot.

PORT POTENTIAL 3D imaging could help further single-incision surgery.

4. User-friendliness
When early-adopting physicians began using the first generation of 3D visualization systems, some of them complained of dizziness or of having a hard time focusing on the imaging subject.

Since then, though, interface innovations have made such complaints much less common. Instead of the heavy headsets the earliest 3D systems utilized, today's leading systems feature lightweight and comfortable polarized sunglasses to see the depth effects on the monitor. As reported in our study, they induce no more side effects than conventional monitor viewing does.

The increasing user-friendliness of 3D imaging extends beyond how it is viewed to what it can view. One manufacturer's 3D laparoscope incorporates a steerable tip with articulation of up to 100 degrees in 4 directions. This provides users a wider view without moving the scope, as opposed to repositioning the scope in order to have a look around. This advance could translate into a reduction in the number of ports placed in the peritoneal cavity.