Surgeons making decisions regarding the appropriate treatment strategy for ureteral stricture or defects should consider the stricture or defect length, location, and etiology; previous treatments; and the patient’s general health status.
For patients with short ureteral strictures or defects, treatment can usually be carried out by endoscopic retrograde or antegrade dilation and resection of the stenosed segment followed by ureteroureterostomy or ureteroneocystostomy. These are widely accepted surgical techniques.
At present, the most difficult problems in clinical treatment are long ureteral strictures or defects such as full-length ureteral avulsion and recurrent adhesion strictures after multiple operations making direct anastomosis impossible. Such lesions lead to challenging clinical management and poor outcomes.
In this study, seven patients, depending on the length of their stricture or defect, were managed with either a bladder muscle flap or a dilated ureter or renal pelvis flap proximal to the stricture, specially designed and used for ureteral reconstruction. The local injury was relatively small, and bowel function was normal. After long-term follow-up, the surgical outcome was satisfactory.
For long-segment ureteral lesions, the simplest approach is to create a cutaneous ureterostomy; however, this is associated with complications including recurrent retrograde infection, peristomal skin infection, and poor quality of life. Thus, this method is not readily accepted by patients except in cases of temporary or palliative treatment. Ureteral replacement with a bowel segment is a surgical option, but the procedure is challenging and complex. The procedure not only disrupts the normal digestive tract but can also cause mucus obstruction of the urinary tract secondary to intestinal fluid secretion, metabolic and electrolyte disorders due to intestinal absorption of urine components, recurrent infection, decreased renal function, and other complications. Among these, the incidence rate of hyperchloremic metabolic acidosis is as high as 19.5%【2,7–9】 .
Although autologous renal transplantation has been used in the treatment of long ureteral defects, the surgical incision is long and the procedure is complex. Kidney transplantation into the patient’s iliac fossa also affects the patient’s quality of life【1】. The buccal mucosa can also be used to repair ureteral strictures or defects, but tissue harvest is limited and usually suited for ureteral lesions shorter than 8 cm【10】.
Using autologous urinary tract tissue for ureteral reconstruction is more reasonable from the viewpoint of anatomical structure and histocompatibility, with the bladder muscle flap being the most widely used.
The bladder blood supply is abundant and has a meshwork-like pattern; thus, the survival rate of bladder flaps for replacement of ureteral defects is high. In 1894, Boari first described the use of a bladder flap for ureteral reconstruction in experimental animals, and in 1947 reported its use in humans with good results【3】. With the advent of minimally invasive surgery, laparoscopic ureteroplasty using a bladder flap is becoming more widely developed【4,5】. However, the above studies reported limitations with the use of bladder flaps to treat long ureteral strictures or defects because such flaps are usually used for ureteral strictures or defects ranging in length from 8 to 12 cm. The conventional use of bladder flaps for ureteral reconstruction of nearly full-length defects is difficult. In four patients of the present study, a spiral bladder flap combined with the psoas hitch technique was used to treat long ureteral strictures or defects, with an innovation to the conventional technique. During the preoperative assessment, a sufficient bladder capacity and an adequate amount of bladder wall for the bladder flap design should be ensured. The bladder capacity should be more than 500 to 600 mL. The bladder needs to be fully mobilized while protecting the bladder flap blood supply. Using the psoas hitch technique, the length of the ureteral defect can be shortened. The bladder flap is designed spirally starting from the highest point of the bladder flap anchorage on the bladder wall and then extending in an anterior, lateral, and posterior direction to ensure a sufficiently long pedicle muscle flap for anastomosis. The bladder flap is fixed at multiple points to the psoas muscle along the ureteral route to reduce tension during ureteroureterostomy. In some patients, the affected kidney can be mobilized and lowered, which can reduce the anastomosis length by about 3 to 5 cm【11】. In addition, studies have shown a reduction in the incidence of ischemic necrosis by using a pedicled greater omentum graft to cover the bladder flap【12,13】.
For patients with an insufficient bladder capacity and a risk of an insufficient bladder flap length, the bowels can be prepared preoperatively so that a procedure involving a combination of a spiral bladder flap, the hitch technique, and an ileal segment for ureteral replacement can be used if necessary 【14】.
In one patient with recurrent lower ureteral stricture following sigmoid bladder augmentation, the pedicled bowel was rolled into a tubular shape and anastomosed with the proximal part of the ureteral stenosed segment.
Other than using a pedicled bladder flap, the significantly dilated pelvis and ureteral segments proximal to the stricture can be used as pedicled urinary muscle flaps for ureteral reconstruction. In one patient with recurrent middle ureteral stenosis with severe local adhesion, insufficient bladder capacity, and a stenosed segment distant from the bladder, the use of a bladder flap was relatively difficult. A dilated ureteral segment pedicle flap proximal to the stricture was chosen for ureteral reconstruction, yielding satisfactory results.
In one patient with recurrent ureteropelvic stricture following surgery, the significantly dilated renal pelvis was used. A spiral renal pelvis flap was designed according to the measured length of the ureteral stricture and then trimmed to size. The flap had a broad base to guarantee an adequate blood supply, which was used for ureteral reconstruction. The postoperative results were satisfactory. In addition, in a study by Kumar et al., the significantly dilated renal pelvis segment was used in the management of hydronephrosis secondary to ureteropelvic obstruction. Renal function was normal at 5 months postoperatively, and urinary tract contrast CT revealed good contrast excretion【15】.
In conclusion, for long-segment, complex ureteral strictures or defects, the adjacent bladder wall, dilated renal pelvis, or ureteral segment wall can be used depending on the etiology, location and length of the lesion. Ureteral reconstruction can be accomplished with accurate measurement and flap design. In the present study, long-term follow-up revealed satisfactory results; therefore, treatment of ureteral strictures or defects with autologous urinary tract muscle flaps can be performed in some complicated cases with good results.