Despite all of the breathless praise being heaped on NOTES at this year’s SAGES, there was still considerable excitement about single port access laparoscopy, another kind of über-minimally invasive surgery that has made great strides over the past year. In this two-part series, we’ll take a look at some of the devices that have made this platform possible.

In SPA procedures, all of the cameras and instrumentation pass through a single trocar, and traction is achieved using deflectable tips on each instrument. Since traditional trocars don’t quite cut it for this application, several new systems have been created that can accommodate multiple instruments while still maintaining pneumoperitoneum.

The first, from Pnavel systems, features three 5mm sleeves and looks like a cow’s udder. There’s room for a camera and two instruments.

The device has already been used to perform successful human procedures: during the emerging technologies session, Dr. Feza Remzi of the Cleveland Clinic described using the Pnavel to perform a right hemicolectomy through a single 3.5cm umbilical incision.

Total operative time was 115 minutes, and the patient was discharged on post-op day 4.

A new device from SurgiQuest technologies, called the AirSeal, takes a different approach: instead of establishing a seal around each instrument, this trocar offers a totally open passage from the outside to the intraabdominal space  – i.e. no diaphragm, gaskets, valves, gels, etc. — and maintains pneumoperitoneum using a pressure barrier. 

The pump, shown in the back here, collects air from the intraabdominal space, warms it, and then recirculates it to create the pressure barrier, as diagrammed below. An analogy was drawn to the air vents that point down over storefronts in the summertime to keep the cool air in and the warm air out.

The pressure barrier is just strong enough to maintain the desired intraabdominal pressure, so if the patient bucks, excess air just comes out.

Dr. David Earle, who presented the device, talked up its ability to prevent camera fogging (because it recirculates warm air) and smudging (because the lens doesn’t touch anything on the way in), but we were more intrigued by its possibilites for single port access. Indeed, Dr. Earle reported performing a successful single-port cholecystectomy on a human using the device, although he didn’t mention how long the procedure ran.

One major advantage of the AirSeal is that, unlike the Pnavel device, it will accommodate as many instruments as can fit in the port, which comes in 12, 18, and 25mm varieties. Moreover, the surgeon is not limited to 5mm devices, which should prove an advantage to those working with bulkier experimental tools.

There are a few areas, however, in which the Pnavel system still comes out on top. Its sleeves, for example, do keep the instruments in a logical orientation with some separation between them. When using the AirSeal, in contrast, it may be harder to find a fulcrum for each instrument, and tools are more likely to bump into and rub against each other. Although Surgiquest has introduced an oval-shaped AirSeal to address the latter problem, it’s not clear how much that will help. In addition, the Pnavel’s cone-shaped opening allows a wide range of normal instrument motion; the AirSeal’s narrow opening, in contrast, may force surgeons to rely more heavily on the instruments’ deflectable tips.

Despite these current shortcomings, we remain optimistic that as people actually use these devices, most of the issues will be identified and resolved.

Stay tuned for our next update on single port access, in which we’ll examine the design and efficacy of the most popular deflectable tip instruments and laparoscopes.