Tips and Tricks for Difficult Ureteral Stent Insertion



Figure 42.1
Insertion of ureteric catheter and retrograde in tortuous ureter ā€“ guidewire removed to allow retrograde study



After the retrograde a guidewire should be inserted through the ureteric catheter into the collecting system and the ureteric catheter exchanged with a stent. A stent inserted with a string (tether) that is left outside the patient can be removed without a further cystoscopy [1].



Difficult Stent Insertion



Vesicoureteric Junction (VUJ)


A tight VUJ may be due to a stenosis or impacted stone. If a standard guidewire will not pass beyond this a sensor wire (Boston Scientific) with a nitinol hydrophilic end or a hydrophilic guidewire (Terumo) can be used. Occasionally the stenosis needs to be dilated to allow access. This can be performed with a 6/7 Fr semi-rigid ureteroscope over a guidewire, a balloon dilator (Uromax, Boston Scientific) or with serial ureteric dilators.

Balloon dilators come in varying lengths. A 4 cm balloon should be used for the VUJ. The maximal balloon inflation pressure should not be exceeded. Dilatation is best performed over a super stiff guidewire. After wire insertion a JJ stent is passed. The VUJ may also be incised with a laser, Collins knife, bugbee electrode or occasionally resected if necessary to gain access. Dilatation is contraindicated in the septic patient with an obstructed system. An urgent nephrostomy with an interval antegrade/retrograde stent should be considered.

If the VUJ is still impassable the procedure should be abandoned and an antegrade approach used (Fig. 42.2). If the guidewire passes through the VUJ but not past the obstruction in the distal ureter I pass a short 6/7 Fr semi-rigid ureteroscope over the wire to the stone and fragment this with a holmium laser. This creates space for the wire to be placed beyond the stone and aid subsequent JJ stent insertion. The size and length of JJ stent to be inserted is dependent on the diameter of the stricture/stenosis that has been dilated and the length of the ureter [3, 6].

A306074_1_En_42_Fig2_HTML.jpg


Figure 42.2
Antegrade removal of a stent, stenotic VUJ secondary to previous ureterolithotomy


The Tortuous Ureter


A tortuous ureter, demonstrated on retrograde, can make guidewire and subsequent stent insertion difficult. A standard 6 Fr ureteric catheter with/without a curved/floppy tip can be used to try and straighten the ureter and navigate the wire around the bend. A hydrophilic tipped wire (Sensor) or hydrophilic wire (Terumo) straight/curved is best in this situation. If this does not pass, an 8/10 Fr coaxial dilator (over a wire) can be used. The stiffness of this often allows the ureter to be straightened. This can be advanced to the renal pelvis and the inner sheath removed and the JJ stent inserted through the outer 10 Fr sheath. If this fails a flexible or rigid ureteroscope can be passed over a wire to the point of curvature (Fig. 42.3). The guide wire is always advanced ahead of the scope under direct vision.

A306074_1_En_42_Fig3_HTML.jpg


Figure 42.3
Insertion of a rigid ureteroscope up tortuous ureter to help guidewire and stent insertion

Another described technique involves inserting a small (7 Fr) occlusion balloon tip catheter under direct vision to the point of curvature and inflating this and pulling the balloon distally to straighten the ureter [2].

Once a ureteric catheter is advanced into the kidney over a hydrophilic wire, the wire should be replaced with a stiffer teflon-coated wire before the ureteric catheter is removed. If these methods fail an antegrade approach will be necessary (Fig. 42.4).
Nov 21, 2017 | Posted by in UROLOGY | Comments Off on Tips and Tricks for Difficult Ureteral Stent Insertion
Premium Wordpress Themes by UFO Themes