PUJ Obstruction in a Transplant Kidney: Reconstruction by Boari Flap

Abstract

Background and Aims:

Renal transplantation remains a crucial treatment for end-stage renal disease, though post-operative complications such as ureteral obstruction can jeopardise graft survival.

Methods:

Here, we report a case of a 52-year-old male with IgA nephropathy who developed ureteric complications following an ABO-compatible renal transplant.

Results:

Despite successful induction therapy and initial discharge with stable graft function, the patient experienced recurrent infections, suture site leakage, progressively worsening hydronephrosis and graft dysfunction. Imaging and nephrostomogram identified a pelviureteric junction (PUJ) obstruction with a short, non-functional ureter unsuitable for conventional reconstruction. After detailed evaluation, a Boari bladder flap reconstruction was performed, successfully establishing a direct connection between the bladder and renal pelvis. Post-surgery, the patient demonstrated stable renal function with improved creatinine levels and no complications during follow-up.

Conclusion:

This case demonstrates the Boari bladder flap’s effectiveness as a practical and efficient method of treating ureteral obstruction in patients with renal transplants whose ureters are impaired in length.

Introduction

The success of renal transplantation depends on the preservation of renal graft function and despite many advances in surgical techniques, immunosuppressive regimens and supportive therapies, many challenges still remain, including post-operative ureteral obstruction. 2%-10% of patients who receive kidney transplants experience ureteric obstruction after surgery; these cases typically manifest within the first few weeks or the first year.^[1,2] Prompt diagnosis and remedial treatment are vital to prevent graft loss.

Case Report

Here we present a case of a 52-year-old male patient. He was CKD-5 having basic renal disease of IgA nephropathy. He received an ABO-compatible renal allograft in July 2022 in Sri Lanka. He had received Basiliximab induction. He had an acute antibody-mediated rejection (biopsy proven) on the 3rd post-operative day and was treated with Plasma Exchange and IVIG. He was discharged with a creatinine of 1.3 mg/dl. On the 15th post-operative day, he developed discharge from the suture site and was re-explored. The leak was sutured and Double J (DJ) stent was re-positioned. The patient had a rising creatinine level and underwent a second kidney biopsy after 15 days at a creatinine level of 3.62 mg/dl. Biopsy showed acute cellular rejection and was treated with Pulse Methylprednisolone and ATG 125 mg for three doses. Post-treatment patient continued to have high-grade fever with chills. The urine sample sent for culture showed significant microbial growth and procalcitonin of 14.7 U. USG showed a graft kidney hydronephrosis with features of pyelonephritis. He was managed with appropriate antibiotics and a nephrostomy tube was placed in view of UTI and hydronephrosis. He was discharged with a serum creatinine of 1.4 mg/dl from the hospital after 15 days with a Foley catheter, nephrostomy tube and DJ stent in situ.

Foley’s catheter was removed after one month. In January 2023, nephrostomy tube was clamped, and removal was attempted however there was significant peri-nephrostomy leakage and nephrostomy tube was replaced.

After nine months of transplant, the patient presented to us with fever and chills. On examination, it was found that the patient had peri-nephrostomy leakage and pus discharge from the suture site. On further evaluation, the patient was found to be in sepsis and was treated with appropriate antibiotics as per the urine culture and sensitivity report. He had a serum creatinine of 2.6 mg/dl on admission. Patient underwent a nephrostomogram which showed pelviureteric junction (PUJ) obstruction with proximal gross hydronephrosis of the transplanted kidney with a non-filling ureter. The ureter length was short and was inappropriate for reconstruction. MRI showed diffuse dilatation of the pelvicalyceal system of the transplanted kidney with constriction at PUJ and the transplant ureter was not dilated.

After consultation with a urologist, patient underwent percutaneous nephroscopy in which PUJ was found to be totally stenosed and the old DJ stent was removed. Pelvis was opened over the scope, bladder tube was constructed and anastomosed to pelvis as Boari bladder flap (Boari flap) over a 6Fr DJ stent. Patient responded well with a good urine output and was discharged with a serum creatinine of 1.2 mg/dl. Patient came for a follow-up after three months with no complaints, good urine output and serum creatinine of 0.8 mg/dl. DJ stent was subsequently removed, and the patient was discharged in a stable condition.

Discussion

Almost 90% of ureteral obstructions following renal transplant have ureteral devascularisation as the primary cause, which results in the creation of intrinsic strictures.^[2] Other causes include mistakes during the ureteroneocystostomy, hematoma, oedema, lymphocele, ureterolithiasis, abscess, bending of a redundant ureter etc.^[3] In our case, ureteral obstruction was likely due to ureteral ischaemia leading to a non-viable distal ureter leaving a short ureter for re-anastomosis.

Boari flap tubularises a part of the urinary bladder roof and has been used for ureteral reconstructions since several decades. In cases when it is difficult or impossible to mobilise the transplanted kidney or in cases of absent, abnormal, short, or non-functional ureters, the Boari flap can be utilised.^[4]

The Boari bladder flap uses only the normal urinary tract, and does not harm the ipsilateral renal blood vessels or contralateral ureter.^[5]

It is a good option for ureteral reconstruction in situations where the original ureter is unavailable or when mobilising the bladder to the renal pelvis or the healthy ureter is not feasible. It is simple to anastomose the flap to the renal pelvis or ureter. In a study by Tonyani et al.^[4] in 2019, the authors found satisfactory surgical outcomes with preserved renal function in patients where ureteral reconstruction was done with a Boari flap.

When dealing with difficult complications following either an autotransplant or allogenic transplant of kidneys, the Boari bladder flap procedure can be a safe and appropriate option in patients with compromised ureters. It enables minimally invasive urologic surgery, eliminates the need for bowel segments, and poses no risk to the opposite kidney.