Robotic ureteroureterostomy for correction of a retrocaval ureter

With an incidence of 1 in 1000 and a male predominant [1], a retrocaval ureter is a rare condition in which the proximal ureter passes posterior to the inferior vena cava (IVC) [2]. This causes ureteral obstruction as the ureter is compressed between the IVC, the posterior abdominal wall and vertebral bodies [2]. More distal to the obstruction, the ureter crosses the IVC anteriorly in normal anatomical position [2]. Patients often present in the third or fourth decade of life with flank pain, nephrolithiasis, hematuria, or urinary tract infections [1]. Retrocaval ureter may also be discovered incidentally on imaging. Management for type 1 retrocaval ureter typically involves surgery to correct the hydronephrosis in patients who have symptoms or deterioration in renal function [1].

A 34-year-old male was erred for incidental right hydronephrosis observed on a CT abdomen and pelvis after a motor vehicle collision. The patient reported right flank pain following the accident. Past medical history and past surgical history were unremarkable. The patient denied hematuria, dysuria, lower urinary tract symptoms, or a history of urinary tract infections. Right costovertebral angle tenderness was present on physical examination. Urinalysis and urine culture were negative. Serum creatinine was 1.17 mg/dL, down from a previous measurement months before the motor vehicle accident of 1.77 mg/dL. A CT urogram revealed severe right hydronephrosis with possible ureteropelvic junction obstruction and diffuse thinning of the right renal parenchyma (Figure 1A and Figure 1B). A diuretic renogram was then obtained due to the thinning of the renal parenchyma and an unknown duration of hydronephrosis on the right kidney. There was a concern that the renal function may have declined over time due to prolonged obstruction. Subsequent diuretic nuclear renogram demonstrated normal uptake and a dilated right renal collecting system with delayed response to Lasix consistent with right partial high-grade obstruction (t1/2 25 minutes) (Figure 2). We then proceeded with cystoscopy with right retrograde pyelography to better detail the origin of the obstructive process. This demonstrated a tortuous proximal ureter with medial deviation and severe hydronephrosis consistent with a retrocaval ureter (Figure 3). The additional investigation using a retrograde pyelogram was performed for better diagnostic testing in case of future intraoperative planning for correction of the ureter. The retrograde pyelogram added details on the course of the proximal ureter and its’ anatomical tortuosity. A ureteral stent was placed for symptomatic relief of obstruction. The patient elected to undergo right robotic-assisted laparoscopic ureteroureterostomy. The patient was given prophylactic antibiotics. He was placed in the left lateral decubitus position with table flexion. Standard 8 mm da Vinci Xi (Intuitive Surgical, Sunnyvale, CA) trocar placement was performed for a right renal procedure (Figure 4). The robotic portion began with medial lection the hepatic flexure and exposure of the right renal pelvis in standard fashion. The renal pelvis was expectedly dilated and prominent. The proximal ureter and IVC were identified. The ureteropelvic junction was dissected and encircled with a vessel loop. The ureter was found to be coursing posterior to the IVC, confirming retrocaval ureter. Identification of the ureter distal to the level of obstruction on the medial side of the IVC in the interaortocaval space was conducted (Figure 5). The distal aspect of the ureter was isolated with a second vessel loop. Care was taken not to unduly devascularize the ureter while mobilizing it to the extent allowing for transection and transposition of the ureter ventral to the IVC. The proximal ureter was sharply transected just distal to the ureteropelvic junction. The previously placed ureteral stent was removed. The ureter was transposed anterior to the IVC without tension (Figure 6). The proximal and distal ends of the ureter were spatulated, and a standard ureteroureterostomy was performed with two running stitches of 4-0 PDS suture (Ethicon, Bridgewater, NJ). Prior to completion of the ureteral anastomosis, a new 6 French, 28 cm double-J ureteral stent was then advanced antegrade over a Sensor wire (Boston Scientific, Marlborough, MA). The proximal stent coil was placed into the renal pelvis, and the anastomosis was completed. A JP drain was placed, and a Foley catheter was kept indwelling.

The patient’s postoperative course was uneventful. His Foley catheter was removed with subsequent JP drain output remaining low and fluid creatinine at the level of serum. The patient was discharged on the first postoperative day. Two weeks later, he reported resolution of his right flank pain. Repeat serum creatinine was 1.0 mg/dL. He returned four weeks later for ureteral stent removal and continued to be pain free.

Retrocaval ureter is classified into two types. Type 1 is more common, accounting for 90% of cases, and is characterized by more distal obstruction behind the IVC at the L3–L4 level [2],[3]. This type resembles a J- or S-shape and can be associated with moderate to severe hydronephrosis [2]. Type 2 represents the remaining 10% of retrocaval ureters and causes mild or no hydronephrosis with obstruction occurring near the level of the renal pelvis [2],[3]. The patient in the present report is deemed to have had a type 1 retrocaval ureter. Imaging is fundamental in the diagnosis of retrocaval ureter, which also serves as a roadmap for surgical correction. Though renal ultrasound may be a first step as it readily identifies hydronephrosis, often it cannot differentiate the source of any distal obstruction. Historically, intravenous pyelography was used to diagnose retrocaval ureter [4],[5]. However, modern cross-sectional imaging such as CT urography provides greater anatomical detail for surgical planning purposes. Retrograde pyelography remains a useful adjunct in cases where CT urography does not sufficiently image the course of the ureter. In this case, the CT urogram failed to detail the course of the ureter posterior to the IVC. On the CT urogram findings, there was severe right hydronephrosis with possible ureteropelvic junction obstruction. The addition of the retrograde pyelogram showed the tortuous proximal ureter with medial deviation and severe hydronephrosis consistent with a retrocaval ureter. Based on the CT urogram findings alone this diagnosis would have been difficult to obtain. The additional of a retrograde pyelogram should be considered when surgeons are concerned for this rare anatomical abnormality. Our patient underwent a robotic ureteroureterostomy for surgical correction of a retrocaval leading to hydronephrosis and flank pain. He was doing well postoperatively and his symptoms improved. The surgical steps of the robotic procedure were detailed, adding a erence and review for surgeons regarding this rare disease process.

Management for type 1 retrocaval ureter typically involves surgery to correct the hydronephrosis in patients who have symptoms or deterioration in right renal function. Our patient underwent a robotic ureteroureterostomy for surgical correction of a retrocaval ureter leading to hydronephrosis and flank pain. The surgery can be performed open or laparoscopically, with or without robotic assistance, based on surgeon perence and experience. This case was performed via the robotic approached due to surgeon perence. Previous literature is sparse regarding the surgical steps for a successful robotic-assisted ureteroureterostomy as detailed in this study.