Although the ureter is functionally simply a tube to transport urine, ureteric surgery requires detailed anatomical knowledge and advanced surgical skills, because the ureter has a delicate blood supply. Therefore, the urological surgeon must have distinct strategies available to bridge ureteric defects of various sites and lengths. Furthermore, handling during and after surgery should be individualized to the patient's pre- and intraoperative situation. In this review, the indications for reconstruction of a specific ureteric defect, the required techniques and postoperative recommendations are discussed.
The ureter is a tube-like structure that connects the renal pelvis to the bladder, transporting the urine from its site of production to its site of storage. The urine is transported by active antegrade peristalsis, ensuring the antegrade passage of urine in all positions of the body. The ureter is composed of three distinct histomorphological layers, the inner mucosa with the lamina propria, the muscularis and the adventitia. The smooth muscle bundles of the tunica muscularis are again arranged in three layers, with an inner longitudinal, a middle circular and an outer longitudinal layer. However, these three layers are arranged in interlacing helices that allow for antegrade peristaltic waves from the PUJ down to the ureteric orifice. The adventitia contains the small penetrating vascular branches for the ureter [1,2].
Most important for the ureter is the surrounding ureteric sheath, a specific layer of the retroperitoneal connective tissue. This sheath both allows the ureter its wide peristaltic movements and a sufficient blood supply. The integrity of the ureteric sheath is of utmost functional importance as its destruction, e.g. during dissection to mobilize the ureter, creates a significant risk of subsequent anatomical or functional ureteric obstruction.
The ureteric vascular supply is ensured by the uretero-subperitoneal arteries, embedded within the ureteric sheath. This vascular plexus receives its arterial supply from various sources, i.e. cranial from the renal artery, the aorta and the gonadal arteries. In the mid-ureter the external supply is sparse and mostly depends on the cranial and caudal inflow. Caudally, the arterial supply emerges from the superior and inferior vesical arteries, and from the internal iliac arteries [1,2].
GENERAL REMARKS ON SURGICAL STRATEGY
Because of the delicate arterial supply of the ureter, no attempt should be made to preserve a (part of the) ureter that has lost both the cranial and the caudal arterial supply. This is obvious for complete ureteric transection, but irreversible damage (at least from one side) to the arterial supply should also be considered in patients with extensive irradiation or fibrosis. Furthermore, the arterial supply may be severely hampered by inadvertent coagulation, ligation or clamping of the ureter, the ureteric sheath or adjacent tissues.
This fragile arterial situation requires caution by the surgeon even in the situation of a ‘simple inadvertent ureteric transection’ in otherwise healthy surrounding tissue. The ureteric ends will retract and ureteric mobilization will be necessary to a allow tension-free anastomosis (a prerequisite for any stricture-free anastomosis). Even in such an ‘easy case’ scenario, the surgeon must pay utmost attention to mobilize both the ureter within its intact ureteric sheath and to limit the length of mobilization to the minimum required to avoid unnecessary disruption of supplying vessels.
Because of the intimate anatomical relationship of the gastrointestinal tract and gynaecological and urological organs with the ureter, advanced carcinomas of the colorectum, the corpus or collum uteri, the vagina or the urothelium often necessitate partial (and sometimes complete) ureteric removal. Given the appropriate indication, these advanced primary or recurrent carcinomas have to be completely extirpated (R0) en bloc to avoid tumour-cell spillage dramatically increasing the risk of a recurrent tumour, with an ominous prognosis. Therefore, intraoperative distinction between tumorous infiltration or inflammatory adhesion should not be attempted, but these organs plus the involved parts of the ureter must be removed with the tumour to ensure an optimal prognosis for the patient. Considering these arguments, resection of the ureter or parts of it must frequently be planned beforehand and often undertaken during surgery for advanced tumours of the small pelvis or the gastrointestinal tract .
PREOPERATIVE DIAGNOSTICS AND PREPARATION
If involvement of the urological organs by an advanced tumour was suspected in the 1980s or early 1990s by bimanual examination, ultrasonography, IVU or CT, there was an attempt to corroborate the diagnosis by invasive diagnostic approaches, e.g. ureteric biopsy or ureterorenoscopy. However, these preoperative findings often did not correlate with the definitive intraoperative situation. These experiences, combined with the constantly improving imaging techniques of colour-coded ultrasonography, CT and MRI, prompted us to dramatically reduce the number of preoperative invasive diagnostic investigations in patients with advanced carcinomas. Currently, if the patient is suitable for surgical resection with suspected involvement of the ureter on CT or MRI, we plan an interdisciplinary surgical approach with no further invasive urological diagnostics.
The patient is informed in detail about the findings and the possible consequences during and after surgery, including the various options for ureteric stenting and/or reconstruction. Written informed consent is obtained that includes the various surgical options available and the specific procedure preferred by the patient, their disadvantages and limitations, and typical complications before and after surgery (see the specific procedures for details).
We consider bowel preparation a necessity for all patients possibly undergoing ileal or colonic surgery, to reduce the incidence of complications like fistula formation or infection. After a day on a low-residue diet, the patient drinks a bowel-cleansing solution until clear stools are obtained (3–4 L). We do not advocate the use of oral antibiotics, but strongly suggest intravenous antibiotics during and after surgery (cephalosporin plus metronidazole) for 3 days.
URETERIC INJURY WITH NO DISRUPTION OF ITS ANATOMICAL INTEGRITY
In many cases of advanced retroperitoneal or pelvic disease, ureteric dissection is necessary over a considerable length, leaving a whitish tube with an obviously questionable blood supply. In this situation at least, the ureter should be stented with an endoscopically placed JJ catheter. As endoscopy is often unrealistic in these surgical cases, we mostly use a small anterior vertical incision of the bladder and place a retrograde ureteric stent, if the duration of stenting is presumed to be brief, or a JJ stent when the stenting is assumed to be for> 2 weeks .
If the blood supply of the ureter is considered inadequate, even in a very localized manner (e.g. after inadvertent coagulation or clamping), and even considering a presumed phase of regeneration, excision of this ureteric part is necessary.
SHORT URETERIC DEFECTS
Most short ureteric defects are caused by simple inadvertent transection of the ureter and subsequent retraction of both ends. In these circumstances with no or only a short deficit in length and atraumatic ureteric ends, an end-to-end anastomosis should be attempted. To gain adequate ureteric length, both ends should be carefully dissected leaving the ureteric sheath intact to ensure an adequate blood supply. Ureteric dissection is sufficient if a tension-free anastomosis can be created safely.
Both ends of the ureter should be incised for 10–15 mm (‘spatulated’) with the incisions on opposite sides (Fig. 1a) and a JJ stent placed (checking that there is adequate insertion into the bladder lumen, by filling the bladder via the indwelling catheter). The edges of the spatulated ureteric ends are slightly trimmed (Fig. 1b) to better fit the opposite ureteric incision. The ends of the ureter are anastomosed with interrupted 4/0 or 5/0 absorbable monofilament sutures, depending on the wall thickness [2,5–7] (Fig. 1c). The suprapubic bladder drain or the indwelling bladder catheter remains in situ for at least 3 days, and the JJ stent for at least 14 days [4,8]. Given a pre-irradiated ureter or otherwise difficult vascular conditions, the JJ remains in place for at least 3 weeks.
DISTAL URETERIC DEFECTS
Although short distal ureteric defects can easily be managed by end-to-end anastomosis or reimplantation, wider distal defects or a questionable distal ureteric blood supply usually require the use of bladder wall. This use of bladder wall tissue enables the surgeon to attend to both the delicate blood supply of the ureter, necessitating a tension-free anastomosis, and the need to prevent urinary reflux.
For defects of up to ≈ 7 cm (crossing of iliac vessels), the ‘psoas hitch’ technique is the most reliable approach. After adequately mobilising the bladder, a horizontal incision is made in the anterior bladder dome. With the aid of two fingers, the dorsolateral bladder wall is elevated above the iliac vessels and this region fixed with absorbable 2/0 traction sutures through the tendon of the psoas minor muscle (Fig. 2a) .
The distal ureter then is implanted to prevent reflux in this bladder ‘horn’ using a submucosal tunnel (Fig. 2b). To create the tunnel a submucosal injection with saline through a fine needle is helpful; the tunnel is then created with fine scissors and the ureter pulled through with the aid of a fine overhold clamp, grasping the ureteric end at the dorsal edge of the ureter. The ureteric end is incised ventrally for ≈ 15 mm and two traction sutures of 4/0 monofilament absorbable material are placed on both edges of the ureter through the bladder muscularis. Then, mucosal sutures are placed with interrupted 4/0 or 5/0 monofilament absorbable sutures.
For wider defects, a pedicled flap of bladder wall (Boari flap) should be considered. This technique allows the bridging of defects up to 12 cm when using spiral bladder flaps (ignoring the vascularization!); combined with the psoas hitch, up to 18 cm of missing ureter may be replaced using a Boari flap. After full bladder mobilization, the bladder is filled almost to capacity and an ipsilateral-based flap (Fig. 3a) cut from the bladder wall. The distal ureter then is implanted to prevent reflux after fixing the flap to the psoas minor muscle (Fig. 3b) with interrupted 2/0 absorbable sutures.
The tunnel and the bladder are closed by a running (2/0 or 3/0) monofilament absorbable suture (Fig. 3c,d). For the Boari and for the psoas hitch technique, we place a 6–10 F stent (depending on the size of the ureter) both in the reimplanted ureter and in the contralateral ureter, and a suprapubic tube in the bladder dome. The stents are left in place for 10 days and the suprapubic tube for 11–12 days, allowing 4–7 days longer in pre-irradiated patients [2,5–7,9,10].
WIDE OR COMPLETE URETERIC DEFECTS
If 15–18 cm of ureter (or even more) is lost, using the bladder wall will not be sufficient to bridge the gap up the proximal ureteric end or even up to the renal pelvis. Four alternatives may be considered in this case, i.e. nephrectomy, renal mobilization (only efficient in rare cases and with one of the above techniques), renal autotransplantation and ureteric replacement with small bowel. These should be explained to the patient in detail with specific emphasis on the individual's general socio-economic and health situation. A fifth alternative, transuretero-ureterostomy, carries a significant risk of compromising adequate urinary transport or causing functional or anatomical ureteric stenosis of the contralateral ureter, and has thus been eliminated from the therapeutic options in most centres.
If small bowel is used for ureteric replacement a distal ileal segment (leaving the distal 15 cm in place and using a more orally situated segment) of appropriate length and sufficient mobility is adequate for most cases. An incision is made into the mesocolon, avoiding vascular damage to the large bowel's blood supply (remembering that this blood supply is different to that of the small bowel, and runs in much wider arcades with the vessels close to the large bowel; as only a few arcades within the mesocolon supply these vessels, care must be taken not to compromise the blood supply) and the segment of ileum pulled through. The stented anastomosis to the proximal end of the ureter or the renal pelvis is made by interrupted monofilament absorbable sutures (Fig. 4a,b). If sufficient bladder capacity is available, we advise a Boari flap to reduce the required bowel length to a minimum. In that case the distal anastomosis is made with 4/0 interrupted absorbable monofilament sutures.
A 6–10 F stent (depending on the size of the ureter) is placed both in the ileal ureter and in the contralateral ureter, and a suprapubic tube in the bladder dome. The stents are left in place for 10 days in the contralateral and for 14 days in the ileal ureter; the suprapubic tube remains for one more day. If the surgical situation was difficult and one or both of the anastomoses not optimal, retrograde opacification should be attempted to visualize the anastomoses before the stents are removed. Allow 4–7 days longer in pre-irradiated patients [2,5–7,10].
COMBINED DEFECTS OF THE DISTAL URETER AND CRANIAL PARTS OF THE BLADDER
Especially in patients with advanced primary recurrent sigmoid or cranial rectal carcinoma, or patients with recurrent cervical carcinoma, a combined defect of the distal ureter(s) and the cranial part of the bladder may occur after en bloc extirpation of the tumour. Here the ureter can be reconstructed in most cases with preservation of the caudal parts of the bladder, leaving the sphincteric zone intact, as the nerve supply is rarely damaged in these tumours of the cranial small pelvis.
To reconstruct a combined defect of the distal ureter(s) and the cranial part of the bladder, a segment of terminal ileum may be preferred over large bowel, as it satisfies both the ureteric and the bladder substitution. Depending on the size of the bladder defect, 30–45 cm of terminal ileum are sufficient. If the centre prefers Studer's ureteric implantation , the oral 8–10 cm is left intact and the remaining segment incised antemesenterically (Fig. 5a). Using the Wallace technique, the ureteric endings are anastomosed to the oral end of the small bowel segment. Depending on the defect of the bladder, the antemesenterically incised part is either sutured to the remaining bladder ‘as is’ or fashioned in a U-shape and then anastomosed to the bladder (Fig. 5b,c). If the centre or the surgeon prefers independent ureteric implantation, both ends of the small bowel segment are left intact for 6–8 cm with the mid-portion incised antemesenterically. Stents are left in place for 10 days in both ureters; the suprapubic tube stays for one more day, allowing 4–7 days longer in pre-irradiated patients.
We deeply appreciate the productive collaboration with Helmut Kreczik, Medical Illustrator, who drew the schematic illustrations.