Amy E. Krambeck, MD, on choosing between CVAC and FANS for suction-based ureteroscopy

CVAC 2.0 and flexible and navigable suction ureteral access sheath (FANS) represent fundamentally different engineering philosophies for stone fragment evacuation—and understanding those differences at a mechanical and surgical-technique level matters as much as the efficacy data when deciding which platform fits a given practice, according to Amy E. Krambeck, MD, professor of urology at Northwestern University Feinberg School of Medicine.

Krambeck drew a clear distinction between the 2 platforms. CVAC is a larger scope designed to be used without a sheath or with a larger sheath, and it favors a dusting approach—laser energy is used to reduce stone to very fine particles that are then aspirated through the scope. FANS, by contrast, is scope-agnostic; the sheath can range from 10 to 15 French, and the approach aligns more naturally with fragmentation.

"You can make it into chunks and then, instead of basketing out those pieces, you're just going to pull them out with suction," Krambeck said. The practical implication is that surgeon technique preference often predicts platform affinity.

"People that were traditionally basketers tend to like FANS, and people that were traditionally dusters tend to gravitate more towards CVAC," she said. "It has a lot to do with your personality and your approach."

On intrarenal pressure—a safety consideration across both platforms—Krambeck was direct. Both systems create elevated pressure, and the mechanisms differ. With FANS, covering the side port holes while suction is off generates a high-pressure irrigation environment. With CVAC, a clogged suction port or sheath-free use combined with high inflow creates similar conditions.

"I think we're seeing more hematomas with CVAC and FANS because we're creating a lot of pressure in the kidney," she said. "We need to be cognizant of that pressure."

On ergonomics, Krambeck welcomed the question. Endourologists have historically carried a disproportionate burden of occupational musculoskeletal injury—cervical spine problems from scope eyepieces in earlier generations, now shoulder, wrist, and back issues driven by lead aprons, heavier instrumentation, and longer cases.

"I think endourologists have notoriously had a lot of orthopedic and neurologic issues," she said. "It's extremely important."

Neither suction platform is without ergonomic cost. CVAC is heavy and physically demanding on the wrist. FANS frequently requires a second person to manage suction on-off cycling and sheath stabilization to achieve efficient throughput.

"They both have positives and negatives," Krambeck said.

She was measured about the field's current posture toward surgeon ergonomics. Hospital systems are beginning to engage with the question—recognizing that surgeon longevity and daily satisfaction have downstream financial implications—but progress remains early. The long-term trajectory, in Krambeck's view, likely points toward robotic assistance for endourologic procedures, though that pathway requires capital investment and institutional buy-in that are not yet widely available.

"We need more advocacy for surgeon health and ergonomics," she said.