Vascular sheath as an alternative technique for encrusted nephrostomy tube exchange

A 76-year-old gentleman was diagnosed with bladder pseudosarcoma following new episodes of haematuria. After resection, a follow-up magnetic resonance imaging showed recurrence, resulting in the insertion of bilateral retrograde ureteric stents followed by bilateral nephrostomies with 8-French drains. This was managed with routine nephrostomy catheter exchanges. However, at this presentation, none of the previously performed techniques were successful.

On attempting to carry out nephrostomy exchange over a guide-wire, fluoroscopy imaging revealed that nephrostomy tube encrustation at several points throughout its length (particularly the hub and the pigtail of the nephrostomy tube) prevented passage of the guide-wire. It was also not possible to use the Terumo wire to aid the exchange.

We, therefore, used a vascular sheath as an alternative technique. Inserting a vascular sheath over the existing nephrostomy tube to straighten the pigtail allowed it to be safely removed without losing access to the renal pelvis. By inserting a guide-wire through the vascular sheath, we were then able to safely position a new, up-sized 10-Fr nephrostomy drain within the renal pelvis. The final position was confirmed by an injection of contrast through the new drain.

It is important to note that the nephrostomy drain needs to be through the vascular sheath before attempting to advance the sheath over the nephrostomy drain. In our case, we cut out the valve on the vascular access sheath to allow the drainage tube through.

Background

Percutaneous nephrostomy, first described by urologist Dr Willard Goodwin in 1955, is a common procedure performed by radiologists. Its indications include relief of urinary obstruction secondary to renal calculi or tumours, infection or diversion of urinary flow [1]. Patients requiring indwelling nephrostomy tubes are at risk of tube encrustation (usually with calcium phosphate) and obstruction [1,2]. Other associated risks are infections resulting in urinary sepsis, and colonisation [3].

Clinical perspective

To prevent the risks, indwelling nephrostomy tubes are usually exchanged every three months [4]. Interestingly, despite routine catheter flushing, the only factor that has been shown to reduce the encrustation rate is adequate hydration [4]. Importantly, tube encrustation poses a real risk to safe removal and exchange. Unsuccessful removal may require further invasive procedures and even open surgery, which in turn pose further morbidity and mortality risks to patients. Some of the other methods described in the literature are extracorporeal shock-wave lithotripsy, percutaneous nephrolithotomy and others [5–7].

Outcome

Successful exchange of an encrusted nephrostomy catheter was achieved using the vascular sheath technique. The frequency of future exchanges was also increased to every two months, as compared to every three months previously, in an attempt to avoid repeated catheter blockages.

Using fluoroscopy imaging in order to guide accurate insertion of a vascular sheath and safe removal of an existing nephrostomy catheter improves the chances of a satisfactory procedural outcome. However, it is important to be mindful of the total radiation dose to patient and to skin, particularly in complicated nephrostomy exchange procedures requiring prolonged radiation exposure.

Take Home Message / Teaching Points

Nephrostomy tube encrustation can pose a challenge for radiologists performing a nephrostomy exchange, as well as for patients, resulting in potential complications, including invasive procedures or even open surgery. Using a vascular sheath by advancing it over the nephrostomy drain when other techniques fail, can serve as a safe alternative and avoid the need for further invasive procedures.

Written informed patient consent for publication has been obtained.