Nephrostomy
Suction Access SheathManawa™ Nephrostomy Suction

Why PCNL Tracts Obstruct and What Suction Changes

A percutaneous tract is a short, wide conduit, which sounds like it should drain freely. In practice it is the fragments that close it. During lithotripsy, pieces large enough to lodge accumulate in the sheath lumen around the nephroscope, and once the outflow path is packed, the irrigation still going in has nowhere to go.

That is the moment intrarenal pressure rises sharply in PCNL — not steadily through the case, but in spikes while the tract is obstructed and the lithotripter is still running. A suction-integrated sheath clears the lumen continuously instead of waiting for the surgeon to notice and withdraw, so the obstruction that drives those spikes does not form.

The secondary benefit is time. Fragments evacuated through the sheath are fragments that do not need to be grasped and withdrawn individually. For the clinical framework around pressure thresholds and monitoring, see our guide to optimising intrarenal pressure.

Standard PCNL and Mini-PCNL

The case for suction is not the same at both ends of the tract-size range, and it is worth being clear about why.

In standard PCNL, the tract is wide enough that passive outflow is usually adequate until fragments pack it. Suction here is about preventing the obstruction events rather than about baseline drainage — the pressure problem is intermittent and tied to lithotripsy activity.

In mini-PCNL, the arithmetic changes. A smaller tract means a smaller annular space around the nephroscope, so the irrigation-to-outflow ratio is unfavourable from the start and pressure is elevated for much of the case rather than in spikes. Active suction is doing continuous work, not occasional rescue, which is why it matters more as tract size comes down.

The same funnel-cone entry, leak-free valve and manual pressure-ventilation slider are used across the range, so the handling is consistent whichever tract size the case calls for.