What is the recommended treatment for patients with ureteropelvic junction obstruction (UPJO) using bypass pyeloplasty?

Management of Ureteropelvic Junction Obstruction (UPJO) Using Bypass Pyeloplasty

Bypass pyeloplasty is an effective surgical technique for ureteropelvic junction obstruction (UPJO), particularly suitable for patients with high inserting ureters, creating a side-to-side anastomosis between the dilated ureter and lower portion of the hydronephrotic renal pelvis. 1

Indications for Surgical Intervention in UPJO

• Surgical intervention for UPJO is indicated when there is evidence of obstruction with deteriorating renal function (>5% decrease in differential renal function), T1/2 >20 minutes on renal scan, decreased renal function (<40% differential function), or worsening drainage on serial imaging 2
• Additional indications include symptomatic obstruction (pain), recurrent urinary tract infections, and pyelonephritis 1, 3
• Preoperative evaluation should include functional renal scans (MAG3 or DTPA) to assess differential renal function and drainage patterns 2

Bypass Pyeloplasty Technique

• Bypass pyeloplasty creates a wide 1-2 cm side-to-side anastomosis between the dilated ureter (just distal to the UPJO) and the lower, dependent portion of the hydronephrotic renal pelvis 1
• Unlike traditional dismembered pyeloplasty, the UPJ remains undisturbed and the renal pelvis is not surgically reduced 1
• This technique is particularly advantageous for patients with mid to high insertion of the ureter 1

Surgical Approaches

• Bypass pyeloplasty can be performed via open, laparoscopic, or robot-assisted approaches 1
• Laparoscopic approaches have shown excellent outcomes with success rates comparable to open surgery, with benefits of shorter hospital stays (mean 3.6 days) 4
• A safety guidewire should be used during the procedure to facilitate rapid re-access to the collecting system if needed 2
• Antimicrobial prophylaxis should be administered prior to the procedure based on prior urine culture results and local antibiogram 2

Outcomes and Efficacy

• Clinical studies show significant improvement in pain scores in up to 92% of patients following laparoscopic pyeloplasty 4
• Improvement in renal scan drainage occurs in approximately 47% of patients 4
• Renal function typically improves (>10% increase) in 23% of patients, remains stable in 66%, and deteriorates in only 11% 4
• Initial results with bypass pyeloplasty specifically show a mean 55% decrease in anteroposterior diameter of the repaired kidney during follow-up 1

Special Considerations

• Low preoperative differential renal function (even <10%) is not a contraindication to pyeloplasty, as studies show no difference in success rates or complications compared to kidneys with better function 3
• In cases of complete avulsion of the ureteropelvic junction, immediate or delayed endoscopic or open repair may be required 2
• If purulent urine is encountered during the procedure, the operation should be aborted, appropriate drainage established, and antibiotic therapy continued 2

Management of Complications

• Potential complications include anastomotic leakage, urinary tract infection, and non-resolving urinomas 5
• Non-resolving urinomas may require ureteric stenting or percutaneous drainage 2
• If stent occlusion occurs, percutaneous nephrostomy may be required to relieve obstruction 6
• In cases of failed primary repair, laparoscopic pyeloplasty has shown 89% objective success rates for secondary UPJO 5

Follow-up Protocol

• Postoperative imaging is essential to evaluate surgical success 2
• Ultrasound and contrast-enhanced ultrasound are recommended for initial follow-up 2
• For more detailed assessment, CT scan with excretory phase or MAG3 renal scan should be performed to evaluate drainage and renal function 2
• Long-term monitoring is recommended to ensure continued patency and improved or stable renal function 4