Magnetically guided camera shows early promise in single-port surgery

Dallas-Use of magnetic anchoring guidance systems (MAGS) to facilitate single-port and natural orifice surgery yielded success in human subjects, according to research presented at the AUA annual meeting in Chicago and subsequently published in Surgical Endoscopy (2009; 23:1894-9).

The technology allows surgery to be performed through a single site but with the technical advantages afforded by a standard laparoscopic approach and without entry restricted to the umbilicus or vagina, said co-author Chad R. Tracy, MD, an endourology fellow at the University of Texas Southwestern Medical Center, Dallas, working with Jeffrey Cadeddu, MD and colleagues. UT Southwestern is co-developing the technology with Ethicon Endo-Surgery, Inc., Cincinnati.

Use of such innovative technologies as laparoendoscopic single-site surgery (LESS) and natural orifice transluminal endoscopic surgery (NOTES) "is increasing dramatically, but because multiple instruments must be introduced through a single incision, these procedures have significant limitations," Dr. Tracy explained.

Outcomes similar to conventional lap

Dr. Tracy presented two cases. One was a nephrectomy in a 50-year-old female with a nonfunctioning right kidney and the other, an appendectomy in a 12-year-old male with acute appendicitis. The procedures were performed using a single-incision working port and a MAGS camera system for the entire dissection. Both procedures were completed successfully, with favorable perioperative outcomes relative to conventional laparoscopic procedures.

The camera used was a commercially available miniature imager placed in a custom-designed magnetic enclosure so it could be controlled within the abdominal cavity by a stacked magnet element placed externally on the abdominal wall. Instrument movement was achieved using variable abdominal wall compression.

"With this technology, instruments can be moved freely during the procedure without limitations associated with initial port placement," Dr. Tracy said.

The system also features an optional needle anchor that is introduced percutaneously and screwed into the upper portion of the camera. The anchor allows the external components to be removed to avoid unintended magnetic attraction between magnetic devices. Since the first procedures were performed, the needle anchor has been downsized to 20-gauge.

Ongoing development aims to improve the coupling of the internal device to the external magnet. Both of the patients described had a very thin abdominal wall (≤2.5 cm), as the forces allow suspension of current instrumentation across the abdominal wall just in excess of 3 cm. Plans also include expanding the system to other surgical tools, such as cautery devices and/or retractors.