Boari Flap Urinary Tract Reconstruction for Rectosigmoid Cancer with Ureteral Invasion: Report of a Case

A woman in her 50s was examined by her local physician for right lower back pain in June 2012. Abdominal contrast-enhanced computed tomography (CE-CT) scans revealed a large pelvic tumor, and the patient was referred to our institute for further investigation. She had no surgical or family history of note. Physical examination revealed a hard tumor about 10 cm in diameter in the lower abdomen. Elevated serum levels of carcinoembryonic antigen and carbohydrate antigen 19-9 level were observed (7.4 and 387 ng/mL, respectively). A type 4 tumor was detected on colonoscopy, 15 cm from the anal verge, and extending 10 cm into the oral side of sigmoid colon (Fig. 1A). Pathologically, the tumor was diagnosed as adenocarcinoma. Barium enema showed a 10-cm luminal narrowing along the long axis (Fig. 1B). CE-CT revealed an ill-defined tumor anterior to the sacrum (Fig. 2A). Right hydronephrosis was noted because of cancerous invasion to the lower two-thirds of the right ureter (Fig. 2B). No metastatic lesions were detected in the lungs, liver, or peritoneum. Contrast-enhanced magnetic resonance imaging (MRI) identified massive direct infiltration and lymphatic invasion into the right mesentery and retroperitoneum (Fig. 3A and 3B). Although extensive tumor invasion was suspected, we performed surgery without neoadjuvant chemotherapy or radiotherapy because there were no unresectable factors such as peritoneal dissemination or infiltration of major vessels. Before surgery, a double J catheter was placed in the stenotic right ureter. On laparotomy, the primary lesion was seen directly invading into the right ureter. We performed low anterior resection with right ureterectomy and regional lymph node dissection. A defect of approximately 10 cm in the ureteral tract resulted from ureteral resection. This long deficit in the ureter made end-to-end anastomosis impossible, so the Boari flap technique was applied for UTR. We made a 10-cm incision from the apex to the anterior bladder wall and performed remnant ureter-to-bladder end-to-end anastomosis (Fig. 4A). After passing a patency catheter from the bladder to the kidney, a small-bore tube was created by interrupted sutures using 4-0 bladed polyglactin (4-0 Vicryl, Ethicon Inc, Somerville, New Jersey) (Fig. 4B). Finally, instrumental colorectal anastomosis was performed. Total blood loss was 535 g, and duration of surgery was 337 minutes. The patency catheter was removed on postoperative day (POD) 13 after contrast radiography confirmed the absence of urinary leakage or stenosis. The patient was discharged on POD 20 without any complications. Macroscopic findings showed a rectal tumor with a maximum diameter of 9 cm (Fig. 4C) and direct invasion to the right ureter (Fig. 4D). Microscopic examination revealed a moderately differentiated adenocarcinoma with right ureteral infiltration. No lymph node metastases were seen in any of the 24 lymph nodes harvested. The final diagnosis was stage 2 according to the Union for International Cancer Control TNM staging system.⁵  After 5-fuluorourasil–based adjuvant treatment for a year, the patient has been followed for 9 years without recurrence or urologic dysfunction.

UTR is sometimes required in various situations of urologic and gynecologic disorders, such as ureteral lithiasis, retroperitoneal fibrosis, trauma, iatrogenic injury, and intrapelvic malignancies. Bladder wall infiltration from a rectosigmoid cancer is relatively common, but ureteral infiltration is much rarer.¹  The survival rate of these cases is reportedly comparatively lower. Russo et al² described a 3-year disease-specific survival rate of 34%, and Stief et al⁶ reported a 5-year overall survival rate of 24.4% after curative resection for urinary tract–invading colorectal cancer. Although the survival rate is far from satisfactory, curative resection is the only option to achieve cure. In such cases, UTR remains indispensable.

Various reconstruction procedures have been reported. Ureter-bladder anastomosis is an uncomplicated method used for short defects less than 3 cm in length.⁷  For deficits up to 5 cm, the psoas hitch procedure is feasible⁸ . This procedure includes ureter-bladder anastomosis with psoas muscle fixation in addition to bladder mobilization. In cases with a defect greater than 5 cm, the Boari flap technique is applicable for urinary reconstruction. The Boari flap technique was first used in 1904 on dogs and was widely applied to humans by Ockerbald.⁹  This technique is suitable for longer ureteral defects¹⁰ , especially those exceeding 10 cm. Benson et al¹¹ reported the superiority of this method from the perspectives of lower morbidity and favorable quality of life (QOL). The cancer in the present case exhibited an aggressive, infiltrating pattern with the primary rectosigmoid tumor invading to the mesentery and resulting in right ureteral infiltration. Because extensive ureteral resection was necessary to obtain curative resection, we considered the Boari flap the most suitable reconstruction for this situation.

The long-term outcomes of the Boari flap technique for urologic and gynecologic disorders have been presented from many institutions,^10–12  but only 4 case reports have described the use of this technique for reconstruction after resection of gastrointestinal malignancy.^3,4  Tan et al⁴ reported use of this reconstruction procedure for 1 primary sigmoid colon cancer case and 2 cases of recurrent colorectal cancer. Tokuoka et al³ performed single-incision laparoscopic sigmoidectomy followed by Boari flap reconstruction for sigmoid colon cancer without complications. The duration of the operation was quite long, at 572 minutes, and whether laparoscopic surgery was feasible is controversial.³ 

We evaluated serum levels of tumor markers and image studies every 4 months, and the patient remains free from recurrence as of 9 years after surgery. Moreover, we did not encounter any complications such as ureteral stenosis, hydronephrosis, urinary tract infection, or urinary incontinence. We believed that the favorable postoperative course and QOL are attributable to the selection of the Boari flap procedure. This highly reliable and safe technique is applicable to not only urologic and gynecologic surgeries but also gastrointestinal surgery.

The Boari flap method appears suitable for not only urologic and gynecologic disorders but also gastrointestinal malignancy. This technique is associated with few urinary tract complications, favorable voiding, and extremely high patient satisfaction.

The authors thank the FORTE company (www.forte-science.co.jp) for English editing. The authors of this case report have no financial and ethical conflicts to disclose.