Ureterocalicostomy

Originally described by Neuwirt in 1947,[1] ureterocalicostomy was slow to gain popularity. The small number of cases was due, in part, to the limited number of appropriate cases and the high restricture rate. Modern ureterocalicostomy was described by Hawthorne et al in 1976.[2] Prior to these authors' innovations, ureterocalicostomy was performed with minimal resection of lower-pole tissue and was prone to anastomotic stricture and obstruction. Hawthorne et al introduced the importance of generous resection of the lower pole, extending cephalad to the intended calyx to be anastomosed to the ureter, in order to free the ureterocaliceal anastomosis from the surrounding cortical tissue. As prenatal ultrasonography has increased the number of UPJ obstruction diagnoses and subsequent procedures used to correct the condition, complications of pyeloplasty have increased the need for this procedure.

Peripelvic fibrosis, a scarred contracted renal pelvis, or an intrarenal pelvis in combination with a proximal ureteral stricture may prevent UPJ reconstruction by standard pyeloplasty or endopyelotomy. Two surgical options remain in this situation: ureteropyelostomy and ureterocalicostomy. Ureteropyelostomy (anastomosing the healthy ureter to the renal pelvis) is preferred, but, if ureteral length is insufficient to perform a tension-free anastomosis (even when combined with a psoas hitch and/or nephropexy), ureterocalicostomy is an option. The kidney is doomed without surgical correction of the obstruction. With the advent of endoscopic surgical procedures, ureterocalicostomy is also used to manage failed endourological procedures or complications caused by them.

Peripelvic fibrosis with long proximal ureteral strictures is usually the result of a failed pyeloplasty or other surgical procedures, stone disease, inflammatory processes, or trauma. Occasionally, similar severe obstruction can be observed in transplanted kidneys in which the transplanted ureter became devascularized during harvest. Horseshoe kidneys have also been salvaged with ureterocalicostomy.

Histologic findings of benign proximal ureteral strictures are nonspecific. Scar formation with collagen deposition and inflammatory infiltrate may be prominent. The obstruction can result in impairment of renal function, pain, infection, and/or stones.

The most common indication for ureterocalicostomy is proximal ureteral stricture in combination with pelvic fibrosis or intrarenal pelvis occurring after multiple failed pyeloplasty attempts. Fortunately, this is extremely rare. Fewer than 0.5% of patients who undergo pyeloplasty subsequently require salvage with ureterocalicostomy. Even more scarce are cases requiring ureterocalicostomy for a horseshoe kidney, ischemic fibrosis of the renal pelvis/ureter in renal transplants, traumatic avulsion of the proximal ureter and/or renal pelvis, extensive fibrosis following surgery for upper urinary tract stone disease, or following ablative techniques such as cryotherapy and radiofrequency ablation of lower pole renal masses.

Clinical symptoms of obstruction include urosepsis, failure to thrive, flank pain or mass, and hematuria. As first described by Dietl, the episodes of flank pain, nausea, and vomiting may present during periods of rapid diuresis with large volumes of liquid intake (so-called Dietl crisis). This may manifest only after consumption of liquids that promote brisk diuresis, such as beer or coffee.

Most patients who require ureterocalicostomy have a history of pyeloplasty, other urinary tract surgery (including ureteroscopy and endopyelotomy), stones, cancer, or trauma.

When pyeloplasty attempts for UPJ obstruction have failed and result in significant peripelvic fibrosis or a relatively long gap between the renal pelvis and the nonobstructed proximal ureter, the kidney can be salvaged with anastomosis of the proximal ureter directly to the lower calyceal system.[3] This technique (ie, ureterocalicostomy) may also be used as the primary reconstructive procedure when a UPJ obstruction or proximal ureteral stricture is associated with a relatively small intrarenal pelvis. In this situation, repeat open or percutaneous pyeloplasty and balloon dilation carry high restricture rates. If an extended length of ureter is not involved in the fibrotic/stenotic process, retrograde endopyelotomy with an Accusize catheter or ureteropyelostomy should be attempted before resorting to other types of repair, including ureterocalicostomy, ileal interposition, buccal ureteroplasty, and autotransplantation.

Ureterocalicostomy is also a useful option when the UPJ is associated with a horseshoe or malrotated kidney in which a standard pyeloplasty does not result in dependent drainage of the collecting system.

Alternatives to ureterocalicostomy include autotransplantation with or without a Boari flap pyelovesicostomy[4, 5] ; ileal interposition graft; long-term nephrostomy tube or ureteral stent placement; renal capsule, peritoneal, or pericardial flap[6] ; Davis intubated ureterotomy,[7]  buccal mucosa graft,[8, 9] and nephrectomy. The decision to perform a nephrectomy must be based on the level of function in the obstructed kidney and the function of the contralateral kidney. If the renal function of the affected kidney is less than 25%, surgical correction has a high risk for failure, and nephrectomy may ultimately be required. If the patient's renal function is less than 10%, recovery is unlikely and initial nephrectomy may be most appropriate.

The ureteral length is 20-30 cm, depending on the individual's height. The lumen size is 4-10 mm in circumference, depending on its location. The narrowest areas are the UPJ, the overpass by the ureter where it crosses over the bifurcation of the iliac arteries, and the ureterovesical junction (UVJ).

In both men and women, the ureter courses posterior to the gonadal vessels and anterior to the iliopsoas muscles, crosses the common iliac artery and vein, and enters inferiorly into the pelvis. In men, the vas deferens loops anterior to the ureter prior to the ureter entering the bladder. In women, the ureter courses posterior to the uterine arteries (hence the "water under the bridge" analogy) and is in close proximity to the uterine cervix prior to reaching the intramural bladder.

The ureteral blood supply comes from multiple sources. Superiorly, the renal artery may branch and supply the ureter, along with the gonadal artery. As the ureter courses through the retroperitoneum, the aorta contributes numerous small branches. In the pelvis, the iliac, vesical, uterine, and hemorrhoidal arteries also contribute to the blood supply of the ureter.

The venous drainage is paired with the arteries. Knowledge of this vascular supply is crucial in ureteral surgery, because a devascularized ureter is subject to complications of stricture and leak. Lymphatic drainage of the upper ureter joins the renal lymphatics to the lumbar nodes. The middle ureter drains to the common and internal iliac nodes. The lymphatic vessels of the pelvic ureter drain to the internal iliac and vesical nodes. For more information about the relevant anatomy, see Ureter Anatomy and Kidney Anatomy.

Contraindications include the following:

• The major contraindication to any ureteral stricture surgery is an active and untreated urinary tract infection.

• A relative contraindication is uncorrected bleeding diathesis.

• If the patient has a terminal malignancy, is extremely elderly, or has a high surgical risk and tolerates internal stenting well, then long-term stenting may be most appropriate.

• If the patient's renal function is less than 10%, then recovery is unlikely and initial nephrectomy may be most appropriate.

• Ureteral obstruction due to retroperitoneal malignancy, lymphadenopathy, or retroperitoneal fibrosis is a relative contraindication to ureterocalicostomy.

• Strictures due to urinary tuberculosis that have not been treated medically and have been stable for less than 3-6 months are also a contraindication because postinflammatory scarring may continue to develop.

• If the length of the ureteral defect prohibits performance of a tension-free ureterocalyceal anastomosis, buccal ureteroplasty, autotransplantation, or ileal interposition is more appropriate.

• The presence of malignancy, primarily transitional cell carcinoma, is a contraindication to ureterocalicostomy. However, peripelvic and focal proximal ureteral fibrosis resulting from endoscopic resection of transitional cell carcinoma or curative chemotherapy and/or radiation for retroperitoneal malignancy may be amenable to ureterocalicostomy, but such cases are rare.

Laboratory studies in the evaluation of candidates for ureterocalicostomy include the following:

• Serum electrolytes/hematology: Standard preoperative laboratory testing is advised, including serum electrolytes and blood counts to help rule out any uncorrected physiologic abnormalities (eg, anemia, hyperkalemia, hypokalemia) that might increase the risks of anesthesia. One would not expect abnormalities in the CBC count directly related to the obstruction unless severe compromise of kidney function or active infection is present. Measures should be taken to correct any abnormality prior to surgical repair.

• Serum blood urea nitrogen (BUN) and creatinine (Cr): Kidney function as indicated by the BUN and Cr values may be normal or elevated (indicating impairment of renal function) depending on the function of the affected and contralateral kidney. Nuclear differential renal function studies, which provide a very accurate measure of renal function, should be performed prior to surgery. However, serum BUN and Cr measurements should be obtained immediately prior to surgery to confirm that no acute change in renal function has occurred and to provide a baseline for postoperative follow-up evaluations.

• Coagulation studies: Coagulation studies, including prothrombin time and activated partial thromboplastin time, should be performed because of the risk of excessive bleeding during resection of the extremely vascular renal parenchyma. Uncorrected coagulopathy is a contraindication to surgical repair. Abnormalities of coagulation parameters most likely would be unrelated to the obstruction. Referral to an internist or hematologist would be appropriate before undertaking surgical treatment. In patients with an elevated serum BUN value, bleeding time should also be evaluated to confirm adequate platelet function.

• Urine studies: Urinary tract infection is a contraindication to ureteral reconstructive surgery. If the patient has a positive urine culture but lacks symptoms of a urinary tract infection, the surgeon should consider a preoperative course of antibiotics to reduce bacterial load in hopes of reducing the chance of postoperative infectious complications. 

Nuclear medicine diuretic scanning is the most widely used test to measure the degree of obstruction and to quantify relative renal function.

The diuretic renal scan allows the measurement of clearance of the radiopharmaceutical over time and the calculation of renal blood flow, which correlates with relative renal function. The most common radiopharmaceuticals currently used to evaluate relative function and obstruction include technetium Tc 99m mercaptotriglycylglycine, which primarily is a tubular agent, and Tc 99m diethylenetriamine pentaacetic acid, which is primarily a glomerular agent. At the peak uptake of radiopharmaceutical, intravenous furosemide, usually 20 mg, is given to induce diuresis and to allow the assessment of urinary clearance.

Diuretic renography showing residual obstruction after a ureteropelvic junction (UPJ) repair should prepare the surgeon for the possible need for ureterocalicostomy. This study also allows determination of differential renal function, assisting in the decision regarding whether the affected kidney has sufficient function (≥ 25% of total renal function) for salvage or whether a nephrectomy is warranted.

An intravenous pyelography (IVP) or CT with excretory phase following intravenous contrast with coronal reconstruction (in institutions where this is available) may be performed to delineate the anatomy of the UPJ. If the patient has poor overall renal function, contrast administration for these studies may cause significant nephrotoxicity. In a completely obstructed system, contrast excretion may be insufficient to clarify the collecting system anatomy.

Antegrade nephrostography often very clearly delineates the renal pelvic anatomy and is generally easily performed, as many candidates for ureterocalicostomy already have a nephrostomy tube in place for temporary drainage. Nephrostography provides as much anatomic information as an IVP or contrast CT scan but without the potential nephrotoxicity of intravenously administered contrast in a kidney that is already at risk for decreased function owing to long-standing obstruction. See images below. Antegrade nephrostography may not accurately delineate ureteral anatomy well depending on the ability of contrast to pass antegrade. In high grade obstructions, the proximal extent of the stricture is all that will be depicted. 

Retrograde pyelography is useful to help delineate the anatomy of the lower ureter when high-grade obstruction has prevented opacification of the portion of the ureter distal to the obstruction. This study also allows placement of a ureteral stent in order to temporarily relieve obstruction and to preserve or to improve renal function and to facilitate localization and dissection of the ureter during ureterocalicostomy. Simultaneous retrograde pyelography and antegrade nephrostography bests delineates the length of the ureteral defect. See images below.

Renal ultrasonography provides excellent anatomical information, including renal parenchymal thickness, echogenicity, and renal growth. Ultrasonography is minimally invasive and is thus useful in monitoring patients after pyeloplasty or ureterocalicostomy. The main drawback is that this modality does not provide any functional data regarding the drainage of the kidney. Thus, nuclear renography may be more useful initially, and renal ultrasonography should be used for long-term follow-up.

Histologic findings of a proximal ureteral stricture and fibrotic renal pelvis are nonspecific. Scar formation with collagen deposition and inflammatory infiltrate may be prominent. In cases of radiation-induced fibrosis, a lack of cellularity and vascular hypertrophy with acellular matrix may be present. Malignant obstruction displays characteristics of the specific carcinoma pathology, most commonly transitional cell carcinoma but occasionally other retroperitoneal tumors such as lymphoma or sarcoma.

Ureteral strictures may be staged based on location, length, and severity. Location is classified as proximal (UPJ to lower pole of the kidney), mid (lower pole of the kidney to the iliac vessels), overlying the iliac vessels, or distal (below the iliac vessels to the ureterovesical junction [UVJ]). Length is the length of the stricture from the proximal to distal extent. For multifocal strictures, this should be measured from the cephalad end of the proximal stricture to the caudad end of the distal stricture, since intervening healthy ureter cannot be salvaged. Severity commonly refers to the patient's degree of obstruction (ie, mild, moderate, severe). Candidates for ureterocalicostomy are predominately those with proximal severe obstruction.

Medical therapy

No medical therapy is available for ureteral stenosis or ureteropelvic junction (UPJ) obstruction.

Surgical therapy

Alternatives to ureterocalicostomy include autotransplantation with a pyelovesicostomy, ureteroileal interposition, buccal ureteroplasty, long-term nephrostomy tube or ureteral stent, renal capsule flap, and nephrectomy. The decision to perform a nephrectomy must be based on the level of function in the obstructed kidney, future risk of chronic kidney disease based on comorbidities, and on the function of the contralateral kidney. If the obstructed kidney is contributing 25% or more of the total renal function, nephrectomy should be avoided, if possible.

Preoperative drainage of an obstructed kidney is recommended if concomitant infection, renal insufficiency, or severe pain is present. A ureteral stent is an option as it allows the patient to avoid external drainage. Although a ureteral stent can facilitate ureteral dissection of the ureter during surgery, it can lead to additional peri-ureteral fibrosis of the non-strictured ureter that may reduce the laxity of the ureter and make reconstruction more challenging. This can improve with 2-4 weeks of stent removal prior to surgery. If the obstruction is of such severity that passage of a stent is not possible or avoidance of ureteral stent is required, percutaneous nephrostomy placement may be necessary.

If the degree of renal function is low enough that nephrectomy is considered, measurements of differential renal function using 24-hour urine collection or nuclear renal scan should be repeated several weeks after temporary drainage is established to determine whether any recovery of function has taken place that would render the kidney salvageable. This also allows documentation of actual baseline kidney function.

Preliminary cystoscopic or antegrade placement of a ureteral catheter can aid in dissection of the ureter and renal pelvis. If near infrared fluoroscence (NIRF) imaging is available, the indocyanine green (ICG) can be instilled in the ureter to aid in ureteral dissection[10] . Surgery can be performed via an open, laparoscopic, or robotic approach based on the surgeon's preferred approach. The ureter is isolated in the retroperitoneum and dissected proximally as far as possible, taking care to preserve a large amount of periureteral tissue. The ureter is then divided just distal to the area of fibrosis (see image below). The proximal ureteral stump is ligated with absorbable suture, even if complete obstruction is present radiologically, to prevent potential leakage into the retroperitoneum.

The kidney is then mobilized to allow access to the lower pole. If the length of ureter is inadequate to reach the lower pole, the kidney can be more thoroughly mobilized to allow it to be displaced downward. The parenchyma over the lower-pole calyx is then resected to reveal the lower pole calyx. The amount of parenchyma to be removed varies with the extent of cortical thinning. Simple incision of the parenchyma, instead of resection, results in postoperative stricture of the ureterocaliceal anastomosis. If substantial parenchymal tissue is present over the lower calyx, the technique may require more careful control of the parenchymal blood supply and maintenance of hemostasis (see Partial Nephrectomy). In a horseshoe kidney, this resection may include removal of the entire isthmus joining the two moieties. See images below.

The proximal ureter is then spatulated laterally, and the ureterocaliceal anastomosis is performed over an internal stent (see image below). An initial interrupted suture of small-diameter (eg, 4-0 or 5-0) absorbable suture material is placed from the apex of the ureteral spatulation to the lateral wall of the calyx. A second interrupted suture is placed from the medial unspatulated wall of the ureter to the medial wall of the calyx, 180° from the initial suture. Approximately 6-10 additional sutures are placed in an interrupted fashion, joining the posterior and anterior aspect of the ureter and calyx. No sutures are tied until all sutures are placed in order to facilitate visualization and careful placement of subsequent sutures. Once sutures are placed circumferentially, they are secured.

If possible, close the renal capsule over the cut surface of the parenchyma, taking care to not compress the ureterocaliceal anastomosis. The anastomosis should be surrounded by viable perinephric fat or omentum (see image below). Consider the placement of a nephrostomy tube and an external drain.

Both a transperitoneal and a retroperitoneal minimially-invasive approach have been described. In the transperitoneal approach, the patient is placed in the 45-60° flank position, and 3-4 ports are placed in the abdomen. The colon is mobilized to gain access to the renal hilum. A 2-cm circular rim of the tip of the lower pole renal parenchyma is excised. The UPJ is then transected, and the ureter is spatulated laterally. End-to-end ureterocaliceal anastomosis is performed in a mucosa-to-mucosa fashion using running 3-0 polyglactin suture. Transperitoneal robotic approaches to ureterocalicostomy have been described, with and without hilar clamping.  In the retroperitoneal approach, the patient is placed in the lateral position with hyperextension. Typically four ports are placed in the retroperitoneum. The perirenal fat is dissected off the kidney circumferentially. The ureter is dissected with periureteral tissues intact from the ureteropelvic junction. Healthy appearing ureteral tissue distal to the level of stenosis is transected and spatulated along its posterolateral border. End-to-end anastomosis ureterocaliceal anastomosis is performed in a mucosa-to-mucosa fashion using running 3-0 polyglactin suture.

External drains are advanced and removed 24-48 hours after any urinary drainage has ceased. If a nephrostomy tube has been placed, nephrostography is performed at least 7-10 days postoperatively. If the study findings show no obstruction or extravasation, the tube is clamped for 12-24 hours and then removed as long as there is no flank pain, fever, or leakage.

Internal stents are removed in an outpatient setting in 4-6 weeks. Perform follow-up evaluations of the functional results with intravenous urography or nuclear renography approximately 2 weeks after stents or nephrostomy tubes have been removed. If the patient becomes symptomatic, performing studies earlier may be indicated. Postoperative study findings should show improvement when compared to preoperative study findings. See the image below.

For excellent patient education resources, see eMedicineHealth's patient education article Intravenous Pyelogram.

Prolonged leakage usually resolves spontaneously. If a ureteral stent is not placed intraoperatively, is removed prematurely, becomes obstructed, or migrates distally with resulting anastomotic drainage persisting for 7-10 days postoperatively or recurring after the external drain has been removed, perform retrograde studies and replace the internal stent.

Urinoma formation secondary to extravasation can occur even with adequate placement of drains, stents, and nephrostomy tubes. This is managed best with direct percutaneous drainage of the fluid collection using ultrasound or CT guidance.

Recurrent stenosis occurs in up to 30% of patients.[3]  If it occurs, options include autotransplantation with a Boari flap pyelovesicostomy, ureteroileal interposition, long-term nephrostomy tube/ureteral stent, and nephrectomy.

Success rates of 70-90% have been reported following ureterocalicostomy. In the largest series reported, 72 patients with a 60-month follow-up demonstrated a success rate of 69.5%.[3] Many patients in whom ureterocalicostomy fails eventually lose the kidney. 

Although the studies involving laparoscopic ureterocalicostomy have been relatively scarce, reported success rates are similar to those of open ureterocalicostomy. Gill et al reported on 2 patients undergoing transperitoneal laparoscopic ureterocalicostomy with documented improvement in renal drainage, although one patient did ultimately undergo nephrectomy because of persistent flank pain.[11] Terai et al reported on one case of a patient undergoing retroperitoneal laparoscopic ureterocalicostomy, with no recurrence at 2-year follow-up.[12]  

According to Radford et al, ureterocalicostomy helps relieve obstruction in children for various indications, including gross pelviureteric junction obstruction with unfavorable anatomy.[13]  Osman et al reached a similar conclusion for the treatment of complex cases of pelviureteric junction obstruction in adults.[14]

More recently, robotic ureterocalicostomy has been reported as successful in the adult and pediatric literature. Mufarrij et al reported his experience with upper urinary tract reconstruction, including one patient treated with robotic ureterocalicostomy.[15] Patient positioning and transperitoneal approach are similar to those used in the laparoscopic approach. The patient remained asymptomatic at 6 months’ follow-up. Casale et al reported on their vast experience of robotic ureterocalicostomy in 9 pediatric patients aged 3-15 years. At 12 months’ follow-up, none of these patients had persistent obstruction as evaluated with nuclear renal scanning, and no major complications were reported. In both adult and pediatric patients, concomitant pyelolithotomy was also performed during the same session.[16] The most extensive cases series focused on the adult population to date was recently published by Chabhra et al, who reported on a series of 6 procedures in 5 patients who underwent robotic ureterocalicostomy,  including a bilateral robotic ureterocalicostomy, at a single center between 2011 and 2015. At a median follow-up of 11 months, there was only one incident of recurrent obstruction.[17]

An element of controversy exists in all salvage procedures for previous surgical failures. Because these severe cases are uncommon and exhibit an array of anatomic findings, direct comparisons of the techniques available for salvage are unavailable. In the absence of such data, urologists usually perform the salvage procedure with which they have the highest comfort level.

The future of urinary tract reconstruction may involve extra–urinary-tract tissue used as grafts or vascular pedicle flaps to replace damaged portions of ureter. Naude reported the successful use of buccal mucosal grafts with omental wrap in 4 patients with segmental ureteric loss,[18] and Tsaturyan et al reported favorable results with the use of buccal mucosa grafts with omental wraps in a series of 5 patients with long ureteral strictures.[19]  Innovative tissue engineering technology may produce ureteral tissue that closely mimics native ureter for ureteral replacement. Similar technology is being used by Atala to engineer bladder, cavernosal, urethral, and ureteral tissue.[20]