Robotic pyeloplasty

What UPJ obstruction is

The renal pelvis is the collecting funnel of the kidney; urine drains out of it into the ureter. Narrowing at the junction of these two structures - the pelvi-ureteric (ureteropelvic) junction, UPJ - causes urine to back up inside the kidney. Over time this can cause pain, recurrent infection, stones or progressive loss of function in that kidney. See UPJ obstruction for the clinical picture.

Who it suits

• Symptomatic UPJ obstruction - pain, recurrent infection, stones.
• Deteriorating function of the affected kidney on serial imaging or renogram.
• UPJ obstruction of any cause - congenital, post-traumatic, post-surgical, or stricture after stone treatment.
• Revision pyeloplasty after a previous procedure where short stenoses are technically suitable.

What the operation involves

The standard technique is the dismembered Anderson-Hynes pyeloplasty performed through the robot. In summary:

1. Positioning in a modified flank position; ports placed; robot docked.
2. Identification of the renal pelvis and the proximal ureter.
3. An aberrant (crossing) renal vessel, if present, is noted and the reconstruction is planned to avoid it.
4. The narrowed segment of the UPJ is excised ("dismembered").
5. The proximal ureter is spatulated.
6. The redundant renal pelvis, if any, is trimmed.
7. A tension-free, water-tight anastomosis is sutured between the pelvis and the spatulated ureter. A ureteric stent is placed across the repair.
8. A drain is placed and the ports are closed.

Dr Kooner's early contribution was the use of the robotic fourth arm as a dedicated retractor, keeping the renal pelvis presented without needing a second bedside assistant for that task.⁶

Hospital stay and stent

Typical hospital stay is one to two nights. The ureteric stent stays in for approximately four to six weeks and is removed at a short cystoscopic procedure. A follow-up renogram is usually performed around three months after surgery to confirm that the repaired UPJ is draining as expected.

Expected outcomes

• Published long-term patency of robotic dismembered pyeloplasty is consistently > 95%.
• Blood loss and length of stay are lower than equivalent open pyeloplasty; cosmesis is improved.
• Recurrent pain and recurrent infection typically resolve after successful reconstruction.

Potential complications

• Urinary leak from the anastomosis - usually resolves with longer stent drainage.
• Re-stenosis - uncommon in primary cases.
• Stent discomfort while the stent is in place.
• Bleeding, infection and standard risks of abdominal surgery (all uncommon).

Alternatives

• Endopyelotomy (an endoscopic incision of the UPJ from inside the ureter) - historically used for short strictures; lower long-term success than dismembered pyeloplasty.
• Laparoscopic or open pyeloplasty where a robot is unavailable.
• Long-term ureteric stent or percutaneous nephrostomy - only appropriate for patients who are not surgical candidates.

Resources