The replacement of large ureteral defect remains an important challenge in urological surgery. The optimal ureteral substitute should have peristalsis to optimize drainage, a good vascularization, minimize absorption stricture and stone formation, and ideally not permit urine reflux. Many techniques have been proposed for ureteral substitution; among these, for the large and proximal defect, only intestinal ureteral replacement such as ileal ureter, Yang-Monti, appendiceal interposition, and colon substitution have been reported [1],[2],[3].

The use of appendix for ureteral defect was first reported by Melnikoff in 1912 [4], its small caliber, intrinsic peristalsis, exclusive vascularization and little tendency to dilation over time make it a suitable ureteral substitute. The earliest studies about appendiceal interposition have been published in pediatric population [5],[6],[7], and showed good long terms results. There are few retrospective studies in adult population with long-term results [8],[9], but most are for right ureter.

The authors report a case of complete left ureter replacement with appendiceal interposition in antiperistaltic position.

The patient was a 64-year-old male with a rectosigmoid adenocarcinoma discovered following abdominal pain. Abdominopelvic computed tomography (CT) revealed probable invasion of the small bowel, bladder, left iliac artery, and left ureter. No distant lesions were noted and cystoscopy was normal. Double J stent was operatively implanted to locate the ureters during surgery. The patient was initially treated with chemotherapy (6 courses of Folfox).

He underwent a large resection of the digestive tumor, which included resection of the rectosigmoid hinge mass, resection of the external iliac artery (repaired with an ilio-iliac bypass), and resection of the left ureter at renal pelvis level.

We opted for a complete left ureteral reconstruction using appendicular transposition.

The bladder and the cecum were mobilized, the appendix was resected at the base to create a tube-like appearance, and was divided from the cecum with preservation of the mesoappendix. The appendix measured approximately 12 cm. Its distal part was anastomosed to the renal pelvis with separate stitches with 4/0 resorbable monofilament. Its proximal part was anastomosed to the bladder without creating an anti-reflux system, after placement of a transparietal mono J ureteral stent, also with separate stitches with 4/0 resorbable monofilament (Figure 1 and Figure 2).

On the digestive side, the patient developed colorectal anastomosis fistula, with bleeding on contact. The patient was treated with an endoscopic clip.

Urologically, the patient developed a urinoma at day 9 (D9) post-op, which resolved with continued ureteral and bladder catheter. The ureteral catheter was removed at D32 and the bladder catheter at D36 post-op.

A follow-up computed tomography urography (CTU) was performed two months after the surgery, confirming the absence of urinary fistula and the good vascularization of the appendix (Figure 3 and Figure 4).

At the last follow-up in consultation, the patient had no backpain, and had not presented any urinary infection. The urinary creatinine was 70 µmol/mL. He had no metabolic problem either.

Because of the large and proximal defect, the options for the patient were limited. We could have discussed left nephrectomy, cutaneous ureterostomy or Bricker diversion, transureteroureterostomy, digestive ureter replacement, and renal autotransplantation.

Nephrectomy was not an option for obvious reasons of preserving renal function. The patient had specified preoperatively that he was opposed to a cutaneous urinary diversion. The autotransplantation was not considered because of the small size of the remaining ureter and the external iliac vascular bypass. As the contralateral ureter was very thin, we decided not to perform transureteroureterostomy to avoid the risk of impacting the contralateral kidney. We proposed the ureter replacement using a digestive segment. Ileum ureteral replacement or Yang-Monti has been well studied in the literature and seems to be a reasonable option for long or very complex ureteral stricture with good long-term results [10],[11],[12],[13].

In the present clinical case the appendix was quite long and well vascularized. We preferred to perform an appendicular interposition to avoid a new digestive anastomosis and a more complex procedure. Its size permits to replace the complete ureter and to perform tension free anastomosis among the proximal left ureter and the bladder dome after mobilization of the cecum without the need for a Boari flap or psoic bladder. We decided to perform an antiperistaltic anastomosis for the appendix with the distal end to the proximal ureter in order to avoid any kind of traction and distortion of the mesoappendix. Studies in pediatric population have shown that both isoperistaltic or antiperistaltic were feasible [5],[6]. In some studies, the antiperistaltic position reduces the risks of ischemia secondary to a kinking of the appendicular meso [14],[15]. Nevertheless, the length of ureter did not permit to make a Lich Gregoir ureterovesical reimplantation, the antiperistaltic position of the appendix may therefore reduce the reflux to the kidney.

In order to protect the anastomosis, we placed a transparietal mono J ureteral stent, there is actually no recommendation for stenting or not in this case. Most of the cases were using double J stent for few weeks [5],[11],[16], even if tubeless appendicular interposition has already been published with good results [17].

In our experience, appendix interposition, when available and disease free, is a feasible and safe option for complete left ureteral defect in selected patients.