Podium 01
病例報告-18歲男性與環繞腔靜脈輸尿管
江衍諭、黃景榆1、蔡佳龍1
義大醫療財團法人義大醫院 外科部 泌尿科；義大醫療財團法人義大大昌醫院 外科部 泌尿科1
A Case report of 18-year-old man with Circumcaval ureter
Yen-Yu Chiang, Ching-Yu Hung1, Chia-lung, Tsai1.
Divisions of Urology, Department of Surgery, E-Da Hospital, Kaohsiung, Taiwan; Divisions of Urology, Department of Surgery, E-Da Dachang Hospital, Kaohsiung, Taiwan1.
Introduction:
Circumcaval ureter, also known as retrocaval ureter or preureteral vena cava, is a rare congenital anatomical anomaly typically associated with upper urinary tract stasis, in which the ureter passes behind the inferior vena cava. Since Hochstetter's initial report in 1893, slightly over 200 cases have been reported worldwide. Furthermore, there are very few documented cases in Taiwan.
Case Description:
We present the case of an 18-year-old male who had a one-year history of a weak urinary stream and hesitancy. He was diagnosed with a right circumcaval ureter, and the kidney function remained unaffected. The condition was successfully managed with a robotic-assisted right ureteroureterostomy, and the postoperative course was uneventful.
Discussion:
Circumcaval ureter can result in varying degrees of hydronephrosis, leading to a non-specific clinical presentation. In most cases, the condition is asymptomatic and is discovered only during imaging, unrelated surgical procedures, or post-mortem examinations. A late diagnosis can lead to severe hydroureteronephrosis, further damaging the kidney and causing a deterioration in renal function.
Conclusion:
While retrocaval ureter is relatively rare, a timely diagnosis is essential and should be considered when evaluating any case of hydronephrosis. CT is the preferred diagnostic procedure, and surgical intervention is warranted in the presence of obstructive uropathy. Compared to the two major datasets available in the literature using open or laparoscopic approaches, robotic repair of retrocaval ureter is also a safe procedure that can be offered to patients.
Introduction
Circumcaval ureter, also known as retrocaval ureter or preureteral vena cava, is a rare congenital anatomical anomaly of the urinary system.
It involves the abnormal positioning of the ureter around the inferior vena cava (IVC) and is present at birth, resulting from the abnormal persistence of the right subcardinal vein ventral to the ureter during IVC embryogenesis. The developing right ureter courses behind and medial to the IVC over the pedicle of the L3-L4 vertebrae, then exits between the IVC and aorta to return to its normal position. This condition can lead to the compression and obstruction of the ureter, potentially causing urinary flow issues, resulting in varying degrees of hydroureteronephrosis (HDNU) and a deterioration in renal function.
The incidence of circumcaval ureter is estimated to be approximately 0.06-0.17% worldwide, making it a relatively rare anatomical variation. However, the actual prevalence may vary in different populations due to the fact that most cases are diagnosed post-mortem, during autopsies. The post-mortem incidence ranges between 1 in 1500 cases and 2 in 1000 cases. One notable trend is that circumcaval ureter is more commonly found in men, with a male-to-female ratio ranging from 2.8:1 to 4:1.
Most cases occur on the right side, except insitus inversus or duplication of the IVC or a persistent left subcardinal vein. Circumcaval ureter typically presents in the third to the fourth decade of life, although some cases have been reported in the first decade and after the fourth decade. The most common presenting features are flank pain and/or recurrent urinary tract infections due to urinary stasis.
Case presentation
An 18-year-old non-diabetic man from a rural background presented at the outpatient department of our institute on November 5, 2018, with complaints of a weak stream and hesitancy persisting for 1 year. He had no history of fever, dysuria, hematuria, or weight loss. Physical examination findings were unremarkable. A complete laboratory evaluation, including urinalysis, a complete blood count, urea, creatinine, and electrolytes, all fell within normal limits.
Ultrasonography (USG) of the kidney, ureters, and bladder showed right-sided hydronephrosis, right proximal ureteral dilation, and pyelocalic dilatation with thinning of the renal parenchyma. This was classified as moderate to severe hydroureteronephrosis (HDUN), designated as SFU-III according to the Society for Fetal Urology grading system (SFU) (Figure 1).
Retrograde Pyelography (RP) revealed a dilated right renal pelvicalyceal system and upper ureter with an abrupt S-shaped turn of the ureter at the level of the L4 vertebra (Figure 2). The RP findings strongly indicated retrocaval ureter. Non-contrast CT urography confirmed proximal HDUN and the characteristic S-shaped loop of the ureter behind the IVC (Figure 3). Magnetic resonance urography (MRU) was subsequently performed with 3D reconstruction, which clearly showed the right ureteral anomaly with the abrupt S-shaped turn of the ureter (Figure 4).
We explained the patient's condition to the patient and his family. After ensuring their understanding and receiving their consent for surgical intervention, we obtained a full informed consent. Subsequently, the patient was admitted to the surgical department of our institute. Pre-operative workup indicated values within normal ranges, and we proceeded with the arrangement for a robotic-assisted right ureteroureterostomy.
Discussion
Since Hochstetter's initial report in 1893, slightly over 200 cases of retrocaval ureter (RCU) have been reported worldwide. In 1935, Kimbrough examined the first case using urography and performed the first successful surgical correction. In 1940, Harrill became the first to diagnose the condition preoperatively. The youngest and oldest cases of RCU, a stillborn acardiac infant, and an 84-year-old male, were reported by Gladstone, both of which were autopsy cases.
Various diagnostic modalities, including intravenous pyelography, retrograde pyelography (RP), inferior vena cavagraphy, abdominal sonography, abdominal CT, and MRI, have been employed for RCU diagnosis. In terms of cost-effectiveness and reduced invasiveness, abdominal CT may be the preferred diagnostic procedure. MRI can be used if the patient has compromised renal function.
In 1982, Bergman classified retrocaval ureter into two clinical types:
Type 1: This is the most common type and is associated with moderate to severe hydronephrosis in about 50% of cases. It exhibits an extreme medial deviation of the middle ureteric segment, resulting in an S or 'fishhook' deformity.
Type 2: This type displays less medial deviation of the ureter, with mild or no associated hydronephrosis, and it constitutes around 10% of cases.
Surgical management is typically reserved for Type 1 cases, which are more likely to be symptomatic. Surgical correction commonly involves ureteral division, resection of stenotic and redundant ureter, relocation, and either ureteroureteral or uretero-pelvic re-anastomosis. This can be accomplished through various approaches, including conventional intra-abdominal or retroperitoneal methods, laparoscopic techniques, or the newly developed robotic-assisted laparoscopic approach.
Circumcaval ureter may co-exist with a solitary kidney or other congenital anomalies. These anomalies can include right double inferior cava, ipsilateral ureterocele, glandular hypospadias, supernumerary lumbar vertebrae, syndactylia, partial situs inversus, solitary kidney, contralateral renal hypoplasia or ectopia, horseshoe kidney, aberrant renal artery, cardiac defects, Turner's syndrome, Goldenhar syndrome, retroperitoneal fibrosis, and polycystic kidney disease. In our cases, no concomitant anomalies were found.
There have been very few reported cases of circumcaval ureter in Taiwan, and no reported cases of surgical intervention utilizing robotic-assisted surgery. In our case, we performed robotic-assisted right ureteroureterostomy, which resulted in rapid patient recovery and short hospital admission days. Our follow-up duration at the hospital extended to 18 months post-surgical intervention, with kidney ultrasonography examinations conducted every 6 months. During the follow-up, kidney ultrasonography revealed a significant improvement in hydroureteronephrosis, with the SFU grading dropping from grade 3 to 0. Renal function remained stable during this period.
Conclusion
While retrocaval ureter is relatively rare, a timely diagnosis is essential and should be considered when evaluating any case of hydronephrosis. CT is the preferred diagnostic procedure, and surgical intervention is warranted in the presence of obstructive uropathy.
Compared to the two major datasets available in the literature that focus on outcomes of retrocaval ureter treatment using open or laparoscopic approaches, robotic repair of retrocaval ureter is also a safe procedure that can be offered to patients.