迷走血管造成腎盂輸尿管接合處阻塞:病例報告

李允仁、樊樂威、李威昌、劉忠一、張英勛

新北市立土城醫院泌尿科

Ureteropelvic junction obstruction by an aberrant vessel: A case report

Yun-Ren Li, Le-Wei Fan, Wei-Chang Li, Chung-Yi Liu, Ying-Hsu Chang

 Department of Urology, New Taipei Municipal Tu Cheng Hospital and Chang Gung University, New Taipei City, Taiwan

Case presentation: A 50-year-old woman with underlying disease of bipolar disorder referred to our clinic with complaints of right lower quadrant of abdominal pain for one month. The pain was dull pain without rebound pain or radiation pain. There was no bowel habit change, no infectious signs or skin lesion. Sonography exam showed right side moderate hydronephrosis with mild increased of cortical echogenicity and normal corticomedullary thickness. Abdominal CT with contrast study showed right hydronephrosis with dilated renal pelvis. One aberrant vessel derived from aorta compression the renal pelvis, which may cause the obstruction. The blood laboratory analyses revealed a concentration of blood urea nitrogen of 22.6 mg/dl, and a level of creatinine of 1.59 mg/dl (eGFR 34 mL/min/1.73m3). The level of hemoglobin was 12.8 g/dl, and the hematocrit was determined to be 39%. The results of the urine analysis revealed a red blood cell count of 3/high power field (HPF) and a white blood cell count of 0/HPF. Blood sugar, phosphate, liver function, serum calcium and electrolyte analyses all yielded results within the normal limits

Under general anesthesia and supine position, a midline incision wound was made. After gentle dissection, an engorged right renal and upper ureter severe adhered to surrounding tissues were noted (Figure2). After adhesiolysis, no obvious compression noted and one accessory artery below ureter was identified. An ureteral stricture site about 1 cm was noted after cut down the ureter. Ureteroureterostomy was done smoothly without any complication.

Discussion: aberrant vessel crossing the UPJ may be the most common extrinsic cause of UPJO above all in older children. These aberrant vessels are thought to cause from 40% to over 50% of extrinsic-UPJO in adults; they are more often ventrally located than dorsally to the UPJ. These aberrant vessels are usually normal morphologic vessels of the lower pole segment, which may be branches from the main renal artery or arise directly from the aorta. Keeley et al reported improvement in the patients undergoing only ligation of crossing vessels. However, there were controversy regarding the potential role of aberrant vessels in the etiology of UPJO. Study using three-dimensional multi-detector row CT demonstrated that the precise location of crossing vessels did not correspond to the obstructive transition point in patients with UPJO. In fact, the true cause is an intrinsic lesion at the UPJ or proximal ureter that causes dilation and ballooning of the renal pelvis over the polar or aberrant vessel.

Back to our scenario, the preoperative image revealed an aberrant vessel crossing the UPJ which seems causing the obstruction. However, intraoperative finding showed marked adhesion over the UPJ and the aberrant vessel goes dorsally and 2cm away from the transitional zone. Aberrant vessel compression may cannot fully explain the cause of obstruction. The resected specimen showed luminal stricture and fibrosis, which more supported to be an intrinsic cause. Therefore, the cause of UPJO in this case may be both intrinsic and extrinsic.