Robotic ureteral reconstruction

The surgical goal of ureteral stricture therapy is to restore a non-obstructive ureter while preserving kidney function. Management includes various treatment options, ranging from procedures such as ureteroneocystostomy to the use of bowel interpositions and buccal mucosa for ureteral reconstruction.

The development of robot-assisted laparoscopic technologies and techniques has led to significant advancements in the minimally invasive treatment of strictures throughout the ureter.

Simultaneous image display enables prompt identification of the ureter in challenging surgical fields when combining a robotic approach with concurrent ureteroscopy. Indocyanine green (ICG) helps delineate vascularized tissue, aiding in the accurate identification of ureteral stenoses. Additionally, a single site surgical system has been introduced, minimising pain and disfigurement associated with surgery.

Benefits and challenges of robotic surgery
The use of robotics facilitates access to the deep pelvis and retroperitoneum, and allows for precise mucosal-to-mucosal anastomosis. This is due to the stable movements, the degrees of freedom provided by robotic wrists, and the magnification from the robotic camera. Recently, there has been a rapid expansion of ureteral reconstructive techniques. Collaborative groups of robotic ureteral surgeons are pooling their experiences to advance the field.

Their collective expertise is helping to define optimal approaches and success rates for rare procedures. Extensive retrospective series have demonstrated comparable success rates of robotic-assisted ureteral reconstruction compared to laparoscopic and open approaches for key procedures such as pyeloplasty and ureteral reimplantation with a shorter hospital stay, reduced blood loss, and better pain control.

Identifying the ureter can be one of the most challenging aspects of the procedure, especially in robotic surgery where there is no tactile feedback. Ureteral inflammation due to the underlying pathology and periureteral fibrosis can further complicate identification by distorting the surgical planes. Successful outcomes in ureteral stricture cases hinge on accurate identification.

Preoperative imaging is important for mapping the ureter's location relative to surrounding structures. Identification manoeuvres, such as clamping the preoperatively placed Foley catheter and administering a diuretic, can enhance ureteral distention and peristalsis, aiding identification.

Several techniques can assist the surgeon. Before the robotic phase, concurrent ureteroscopy can be performed, guiding an open-ended catheter to the illuminated level. Injecting indocyanine green intraureterally allows visualisation of the ureter under near-infrared fluorescence, effectively identifying the proximal and distal limits of a stricture.

Pyeloplasty
The surgical management of ureteropelvic junction obstruction (UPJO) has traditionally been performed with open dismembered pyeloplasty (OP), following the Anderson-Hynes technique, which was long considered the gold standard treatment for UPJO, boasting a success rate of over 90%. An omental or peri-nephric fat flap may be wrapped around the reconstructed ureter and pexed in place.

The laparoscopic approach was introduced by Schuessler et al. in 1993 and quickly became a globally accepted alternative to OP. This minimally invasive technique offered benefits such as shorter hospital stays, lower morbidity, and reduced need for analgesics. Robot-assisted laparoscopic pyeloplasty (RALP), first described in 1999, has since been recognised as an effective and reliable minimally invasive treatment for UPJO.

Gettman et al. published the first series of nine RALP patients in 2002, reporting a 100% successrate. The robotic surgical platform presents a viable alternative for UPJO treatment, offering advantages such as 3D visualisation, magnification of the operative field, enhanced dexterity and ergonomics, and motion scaling with tremor reduction systems that facilitate precise dissection and intracorporeal suturing.

The Da Vinci robotic system retains the benefits of minimally invasive techniques, including reduced postoperative pain, shorter hospital stays, and improved cosmetic outcomes. Additionally, the
learning curve in RALP seems to be shorter compared to laparoscopic pyeloplasty.

Proximal and mid ureter
For short strictures measuring 2-3 cm in the proximal and mid ureter, ureteroureterostomy is utilised. This procedure involves excising the narrowed segment of the ureter, spatulating the ureter, and performing an end-to-end reanastomosis. Typically, as with pyeloplasty, a double-J stent is placed intraoperatively to bridge the anastomosis and is left in place for approximately four weeks postoperatively.

Additionally, a peritoneal or omental flap can be used to improve blood supply at the anastomosis site. Due to its proximity to the kidney, a pyeloplasty can also be performed for proximal strictures. Complete mobilisation of the kidney and caudal nephropexy can create additional space for a tension-free reconstruction. An open surgical approach is usually conducted via a lumbar flank incision for proximal strictures or an extraperitoneal transversus abdominis incision for mid-ureteral strictures.

When using the robotic-assisted technique, the patient is positioned in a modified 60-degree flank position. The ipsilateral arm is secured at the patient's side to prevent interference with the robotic arms. Ports are arranged in a straight-line configuration along the lateral border of the rectus muscle.

For long ureteral defects, surgical options such as transureteroureterostomy, renal autotransplantation, or ureteral replacement may be indicated. Ureteral replacement using reconfigured ileal segments following the Yang-Monti procedure has shown good results.

Replacing long ureteral segments remains a significant challenge and is typically chosen as a last resort when other methods are not feasible. Various techniques have been tested in the past, including the interposition of free or pedicled grafts and artificial materials. Among these techniques, intestinal ureteral replacement, including ileum, colon, and appendix interposition, as well as the more recently used buccal mucosa grafts, have proven to be effective.

The use of an ileal interposition was first described in 1906 for treating long strictures in urogenital tuberculosis and has since become an established method for managing extensive strictures. The small bowel segment is taken about 30 cm distal to the ileocecal valve and can be anastomosed either proximally and distally to the ureter or as a complete replacement directly to the renal pelvis and bladder. Robot-assisted procedures are also possible, offering similar functional outcomes with faster patient recovery and reduced need for analgesics.

Buccal mucosa graft (BMG) ureteroplasty
The first human use of BMG for ureteral reconstruction was described in 1999, and since then, several case series have reported the use of BMG in the open repair of ureteral strictures. For robot-assisted ureteral reconstruction with buccal mucosa grafts (RU-BMG), there are two main techniques. The onlay technique involves making a longitudinal incision in the strictured ureter and attaching a BMG to the defect with absorbable sutures. The augmented anastomotic technique entails excising the strictured portion of the ureter, anastomosing a posterior plate of healthy ureter with absorbable sutures, and attaching a BMG to the remaining defect using absorbable sutures. The onlay technique is mainly used for narrowed strictures, while the augmented anastomotic technique is employed for obliterative strictures. The BMG is harvested by hydrodissecting the buccal mucosa with lidocaine and epinephrine and then excising it from the buccinator muscle. The graft length is determined by measuring the ureteral defect intracorporeally, and the graft width is 10-15mm.

Few reports exist on robot-assisted ureteroplasty using BMG. Zhao et al. reported a 100% success rate in four patients, with no extravasation on pyelogram and no hydronephrosis on follow-up ultrasound over a period of 10.7–18.6 months. Techniques include dorsal and ventral onlays as well as augmented anastomotic ureteroplasty for obliterated segments of the proximal ureter. Zhao et al. also reported a multi-institutional study of robotic BMG ureteroplasty in seven patients, all showing no ureteral obstruction on follow-up.

Distal ureter
Reconstruction of the distal ureter is a common urological procedure. Due to the high risk of fistula formation and an increased risk of recurrence,end-to-end anastomosis is rarely chosen in this context. Ureteroneocystostomy is suitable for treating distal ureteral strictures and is often combined with a Boari flap and/or a psoas hitch.

For an open surgical approach, an extraperitoneal Pfannenstiel incision, a Gibson incision, or an extraperitoneal laparotomy in the lower abdomen is typically used. In recent years, laparoscopic and robot assisted surgery have gained increasing importance in this area.

The efficacy of minimally invasive robotic surgery for ureteral reimplantation has gained wide acceptance. Patil et al. described 12 patients operated on by three surgeons, with a mean operative time of 208 minutes and mean estimated blood loss of 48 mL, reporting no intraoperative or postoperative complications. Lee et al. similarly reported successful stricture treatment in all patients without postoperative complications.

In a contemporary series by Wason et al., all patients had successful robotic ureteral reimplantation with a mean follow-up of 10 months, showing resolution of hydronephrosis due to benign stricture disease. These studies demonstrate that robotic ureteral reimplantation is feasible and produces comparable outcomes to open repair. Few comparative studies evaluate the differences between open and robotic ureteral reimplantation finding decreased estimated blood loss in the laparoscopic and robotic groups compared to the open group.

Indocyanine green (ICG)
With the integration of near-infrared fluorescence (NIRF) imaging using ICG into robotic platforms, the application of this imaging technology has significantly advanced for reconstructive procedures. Intraoperative localisation of the ureteral stricture is achieved through instilling ICG above and below the stenosis through a ureteral catheter, a percutaneous nephrostomy tube, or both. The fluorescent tracer appears as a green colour and helps to identify the ureter course to improve the success of robotic ureteral repair. Administering ICG helps distinguish healthy ureter tissue from diseased tissue especially in complex reconstructive cases to reduce the risk of iatrogenic damage, protect the ureteral blood supply and helps to perform tension-free ureteral anastomosis.

Single port (SP)
The da Vinci SP® robotic system allows for the insertion of three double-jointed wristed instruments and a fully wristed 3D camera through a single port. For ureteral reconstruction within the pelvic cavity, where the target area is deep, the working space is narrow, and the operative field is small, the SP system offers potential advantages. Additionally, the cosmetic outcome of the SP system is superior to multiport robotic surgery because the SP trocar is inserted through an umbilical incision.

Various studies have shown that the SP system has the potential to be used for various types of robotic ureteral reconstruction.

Conclusion
The treatment planning for ureteral strictures requires a detailed consideration of stricture and patient characteristics. Given the diverse options for ureteral reconstruction, various methods must be considered for each patient.

Robotic-assisted laparoscopic surgery is rapidly gaining popularity, likely due to the shorter learning curve, greater surgeon comfort, and easier intracorporal suturing. This has allowed a lot more surgeons to perform the procedure. By using the surgical robot, minimally invasive procedures can also be offered to patients who previously required open surgery with a larger incision. Smaller incisions lead to less stress and restriction. In addition, the extremely high precision of the movements of the robotic instruments makes it easier to perform a gentle and safe procedure.

Robotic surgery can reduce surgery-related pain and intraoperative blood loss. Patients benefit from smaller and cosmetically more favourable wounds, which lead to faster healing and discharge from the hospital.