Minimally invasive relief of uretero-pelvic junction obstruction, especially in conjunction with renal pelvic stones.

• On preoperative day #1 –Placement of ipsilateral ureteral and bladder catheter.
• Positioning of patient (prone position, bolsters elevating flank).
• Opacification of upper urinary tract and identification of obstructed UPJ and possible stones.
• Planning of access route with fluoroscopy head at 90°.
• Puncture of collecting system with fluoroscopy head at 30° using 18 Ga needle (“bull’s eye”–needle tip and hub superimposition), ideally through upper or middle calyceal group, for easier visualization and access to UPJ. Assessment of depth of puncture with fluoroscopy head at 90°.
• Introduction of hydrophilic guidewire (0.035) through needle sheath and passage past obstructed UPJ.
• Skin incision at puncture site and dilation of access tract using axial dilators (Amplatz) or dilation balloon (Nephromax) to 30Fr.
• Introduction of nephroscope, inspection of pelvicalyceal system and obstructed UPJ.
• Retrieval of proximal end of ureteral catheter with forceps, and introduction of stiff guide wire (0.035) through it.
• Advancement of stiff guidewire to exteriorization through distal tip of ureteral catheter, and removal of catheter over wire. Stiff guidewire now provides maximum safety and access to urinary tract through distal (urethra) and proximal points (nephrostomy tract).
• Introduction of endoscopic scissors through nephroscope, full thickness section of obstructed UPJ at lateral aspect.
• Placement of 14/7Fr endopyelotomy double J stent over guidewire.
• Placement of nephrostomy tube for adequate urine drainage.